Turbulent kinetics of a large wind farm and their impact in the neutral boundary layer

DOE PAGES

Na, Ji Sung; Koo, Eunmo; Munoz-Esparza, Domingo; ...

2015-12-28

High-resolution large-eddy simulation of the flow over a large wind farm (64 wind turbines) is performed using the HIGRAD/FIRETEC-WindBlade model, which is a high-performance computing wind turbine–atmosphere interaction model that uses the Lagrangian actuator line method to represent rotating turbine blades. These high-resolution large-eddy simulation results are used to parameterize the thrust and power coefficients that contain information about turbine interference effects within the wind farm. Those coefficients are then incorporated into the WRF (Weather Research and Forecasting) model in order to evaluate interference effects in larger-scale models. In the high-resolution WindBlade wind farm simulation, insufficient distance between turbines createsmore » the interference between turbines, including significant vertical variations in momentum and turbulent intensity. The characteristics of the wake are further investigated by analyzing the distribution of the vorticity and turbulent intensity. Quadrant analysis in the turbine and post-turbine areas reveals that the ejection motion induced by the presence of the wind turbines is dominant compared to that in the other quadrants, indicating that the sweep motion is increased at the location where strong wake recovery occurs. Regional-scale WRF simulations reveal that although the turbulent mixing induced by the wind farm is partly diffused to the upper region, there is no significant change in the boundary layer depth. The velocity deficit does not appear to be very sensitive to the local distribution of turbine coefficients. However, differences of about 5% on parameterized turbulent kinetic energy were found depending on the turbine coefficient distribution. Furthermore, turbine coefficients that consider interference in the wind farm should be used in wind farm parameterization for larger-scale models to better describe sub-grid scale turbulent processes.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Na, Ji Sung; Koo, Eunmo; Munoz-Esparza, Domingo

High-resolution large-eddy simulation of the flow over a large wind farm (64 wind turbines) is performed using the HIGRAD/FIRETEC-WindBlade model, which is a high-performance computing wind turbine–atmosphere interaction model that uses the Lagrangian actuator line method to represent rotating turbine blades. These high-resolution large-eddy simulation results are used to parameterize the thrust and power coefficients that contain information about turbine interference effects within the wind farm. Those coefficients are then incorporated into the WRF (Weather Research and Forecasting) model in order to evaluate interference effects in larger-scale models. In the high-resolution WindBlade wind farm simulation, insufficient distance between turbines createsmore » the interference between turbines, including significant vertical variations in momentum and turbulent intensity. The characteristics of the wake are further investigated by analyzing the distribution of the vorticity and turbulent intensity. Quadrant analysis in the turbine and post-turbine areas reveals that the ejection motion induced by the presence of the wind turbines is dominant compared to that in the other quadrants, indicating that the sweep motion is increased at the location where strong wake recovery occurs. Regional-scale WRF simulations reveal that although the turbulent mixing induced by the wind farm is partly diffused to the upper region, there is no significant change in the boundary layer depth. The velocity deficit does not appear to be very sensitive to the local distribution of turbine coefficients. However, differences of about 5% on parameterized turbulent kinetic energy were found depending on the turbine coefficient distribution. Furthermore, turbine coefficients that consider interference in the wind farm should be used in wind farm parameterization for larger-scale models to better describe sub-grid scale turbulent processes.« less

Experimental study of thin film sensor networks for wind turbine blade damage detection

NASA Astrophysics Data System (ADS)

Downey, A.; Laflamme, S.; Ubertini, F.; Sauder, H.; Sarkar, P.

2017-02-01

Damage detection of wind turbine blades is difficult due to their complex geometry and large size, for which large deployment of sensing systems is typically not economical. A solution is to develop and deploy dedicated sensor networks fabricated from inexpensive materials and electronics. The authors have recently developed a novel skin-type strain gauge for measuring strain over very large surfaces. The skin, a type of large-area electronics, is constituted from a network of soft elastomeric capacitors. The sensing system is analogous to a biological skin, where local strain can be monitored over a global area. In this paper, we propose the utilization of a dense network of soft elastomeric capacitors to detect, localize, and quantify damage on wind turbine blades. We also leverage mature off-the-shelf technologies, in particular resistive strain gauges, to augment such dense sensor network with high accuracy data at key locations, therefore constituting a hybrid dense sensor network. The proposed hybrid dense sensor network is installed inside a wind turbine blade model, and tested in a wind tunnel to simulate an operational environment. Results demonstrate the ability of the hybrid dense sensor network to detect, localize, and quantify damage.

Computational analysis of vertical axis wind turbine arrays

NASA Astrophysics Data System (ADS)

Bremseth, J.; Duraisamy, K.

2016-10-01

Canonical problems involving single, pairs, and arrays of vertical axis wind turbines (VAWTs) are investigated numerically with the objective of understanding the underlying flow structures and their implications on energy production. Experimental studies by Dabiri (J Renew Sustain Energy 3, 2011) suggest that VAWTs demand less stringent spacing requirements than their horizontal axis counterparts and additional benefits may be obtained by optimizing the placement and rotational direction of VAWTs. The flowfield of pairs of co-/counter-rotating VAWTs shows some similarities with pairs of cylinders in terms of wake structure and vortex shedding. When multiple VAWTs are placed in a column, the extent of the wake is seen to spread further downstream, irrespective of the direction of rotation of individual turbines. However, the aerodynamic interference between turbines gives rise to regions of excess momentum between the turbines which lead to significant power augmentations. Studies of VAWTs arranged in multiple columns show that the downstream columns can actually be more efficient than the leading column, a proposition that could lead to radical improvements in wind farm productivity.

Stability Augmentation of Wind Farm using Variable Speed Permanent Magnet Synchronous Generator

NASA Astrophysics Data System (ADS)

Rosyadi, Marwan; Muyeen, S. M.; Takahashi, Rion; Tamura, Junji

This paper presents a new control strategy of variable speed permanent magnet wind generator for stability augmentation of wind farm including fixed speed wind turbine with Induction Generator (IG). A new control scheme is developed for two levels back-to-back converters of Permanent Magnet Synchronous Generator (PMSG), by which both active and reactive powers delivered to the grid can be controlled easily. To avoid the converter damage, the DC link protection controller is also proposed in order to protect the dc link circuit during fault condition. To evaluate the control capability of the proposed controllers, simulations are performed on two model systems composed of wind farms connected to an infinite bus. From transient and steady state analyses by using PSCAD/EMTDC, it is concluded that the proposed control scheme is very effective to improve the stability of wind farm for severe network disturbance and randomly fluctuating wind speed.

Design and Analysis of Horizontal Axial Flow Motor Shroud

NASA Astrophysics Data System (ADS)

Wang, Shiming; Shen, Yu

2018-01-01

The wind turbine diffuser can increase the wind energy utilization coefficient of the wind turbine, and the addition of the shroud to the horizontal axis wind turbine also plays a role of accelerating the flow of the condensate. First, the structure of the shroud was designed and then modeled in gambit. The fluent software was used to establish the mathematical model for simulation. The length of the shroud and the opening angle of the shroud are analyzed to determine the best shape of the shroud. Then compared the efficiency with or without the shroud, through the simulation and the experiment of the water tank, it is confirmed that the horizontal axis of the shroud can improve the hydrodynamic performance.

Methodology of shell structure reinforcement layout optimization

NASA Astrophysics Data System (ADS)

Szafrański, Tomasz; Małachowski, Jerzy; Damaziak, Krzysztof

2018-01-01

This paper presents an optimization process of a reinforced shell diffuser intended for a small wind turbine (rated power of 3 kW). The diffuser structure consists of multiple reinforcement and metal skin. This kind of structure is suitable for optimization in terms of selection of reinforcement density, stringers cross sections, sheet thickness, etc. The optimisation approach assumes the reduction of the amount of work to be done between the optimization process and the final product design. The proposed optimization methodology is based on application of a genetic algorithm to generate the optimal reinforcement layout. The obtained results are the basis for modifying the existing Small Wind Turbine (SWT) design.

Dynamic wake model with coordinated pitch and torque control of wind farms for power tracking

NASA Astrophysics Data System (ADS)

Shapiro, Carl; Meyers, Johan; Meneveau, Charles; Gayme, Dennice

2017-11-01

Control of wind farm power production, where wind turbines within a wind farm coordinate to follow a time-varying power set point, is vital for increasing renewable energy participation in the power grid. Previous work developed a one-dimensional convection-diffusion equation describing the advection of the velocity deficit behind each turbine (wake) as well the turbulent mixing of the wake with the surrounding fluid. Proof-of-concept simulations demonstrated that a receding horizon controller built around this time-dependent model can effectively provide power tracking services by modulating the thrust coefficients of individual wind turbines. In this work, we extend this model-based controller to include pitch angle and generator torque control and the first-order dynamics of the drive train. Including these dynamics allows us to investigate control strategies for providing kinetic energy reserves to the grid, i.e. storing kinetic energy from the wind in the rotating mass of the wind turbine rotor for later use. CS, CM, and DG are supported by NSF (ECCS-1230788, CMMI 1635430, and OISE-1243482, the WINDINSPIRE project). JM is supported by ERC (ActiveWindFarms, 306471). This research was conducted using computational resources at MARCC.

Fusion of a FBG-based health monitoring system for wind turbines with a fiber-optic lightning detection system

NASA Astrophysics Data System (ADS)

Krämer, Sebastian G. M.; Wiesent, Benjamin; Müller, Mathias S.; Puente León, Fernando; Méndez Hernández, Yarú

2008-04-01

Wind turbine blades are made of composite materials and reach a length of more than 42 meters. Developments for modern offshore turbines are working on about 60 meters long blades. Hence, with the increasing height of the turbines and the remote locations of the structures, health monitoring systems are becoming more and more important. Therefore, fiber-optic sensor systems are well-suited, as they are lightweight, immune against electromagnetic interference (EMI), and as they can be multiplexed. Based on two separately existing concepts for strain measurements and lightning detection on wind turbines, a fused system is presented. The strain measurement system is based on a reflective fiber-Bragg-grating (FBG) network embedded in the composite structure of the blade. For lightning detection, transmissive &fiber-optic magnetic field sensors based on the Faraday effect are used to register the lightning parameters and estimate the impact point. Hence, an existing lightning detection system will be augmented, due to the fusion, by the capability to measure strain, temperature and vibration. Load, strain, temperature and impact detection information can be incorporated into the turbine's monitoring or SCADA system and remote controlled by operators. Data analysis techniques allow dynamic maintenance scheduling to become a reality, what is of special interest for the cost-effective maintenance of large offshore or badly attainable onshore wind parks. To prove the feasibility of this sensor fusion on one optical fiber, interferences between both sensor systems are investigated and evaluated.

The dynamic inducer as a cost-effective wind turbine system

NASA Astrophysics Data System (ADS)

Gyatt, G.; Zalay, A.

The efficacy of dynamic inducer tip vanes, short airfoil sections attached perpendicularly at the outer end of wind turbine rotors, were investigated analytically and experimentally. The airfoil section is oriented to lift toward the center of the rotor, thereby forcing a greater flow toward the center of the actuator disk. Also, since the vortex shed by one tip vane posterior edge is exactly opposite in sign to the vortex produced at the anterior edge of the immediately preceeding vane, a synchronous state arises wherein drag on the tip vanes is eliminated. A numerical model was developed for the wind turbine power coefficient in a synchronous state. The simulation indicated that more kinetic energy than present in the actuator disk alone can be captured. Design features of the blades and fairing are described. Dynamic inducer WECS were projected to cost 20% less than equivalent conventional horizontal axis machines, while power augmentation can approach 70%, thus exceeding the Betz limit.

Solution of the Fokker-Planck equation in a wind turbine array boundary layer

NASA Astrophysics Data System (ADS)

Melius, Matthew S.; Tutkun, Murat; Cal, Raúl Bayoán

2014-07-01

Hot-wire velocity signals from a model wind turbine array boundary layer flow wind tunnel experiment are analyzed. In confirming Markovian properties, a description of the evolution of the probability density function of velocity increments via the Fokker-Planck equation is attained. Solution of the Fokker-Planck equation is possible due to the direct computation of the drift and diffusion coefficients from the experimental measurement data which were acquired within the turbine canopy. A good agreement is observed in the probability density functions between the experimental data and numerical solutions resulting from the Fokker-Planck equation, especially in the far-wake region. The results serve as a tool for improved estimation of wind velocity within the array and provide evidence that the evolution of such a complex and turbulent flow is also governed by a Fokker-Planck equation at certain scales.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karr, Dale G.; Yu, Bingbin; Sirnivas, Senu

To create long-term solutions for offshore wind turbines in a variety of environmental conditions, CAE tools are needed to model the design-driving loads that interact with an offshore wind turbine system during operation. This report describes our efforts in augmenting existing CAE tools used for offshore wind turbine analysis with a new module that can provide simulation capabilities for ice loading on the system. This augmentation was accomplished by creating an ice-loading module coupled to FAST8, the CAE tool maintained by the NREL for simulating land-based and offshore wind turbine dynamics. The new module includes both static and dynamic icemore » loading that can be applied during a dynamic simulation of the response of an offshore wind turbine. The ice forces can be prescribed, or influenced by the structure’s compliant response, or by the dynamics of both the structure and the ice floe. The new module covers ice failure modes of spalling, buckling, crushing, splitting, and bending. The supporting structure of wind turbines can be modeled as a vertical or sloping form at the waterline. The Inward Battered Guide Structure (IBGS) foundation designed by Keystone Engineering for the Great Lakes was used to study the ice models coupled to FAST8. The IBGS foundation ice loading simulations in FAST8 were compared to the baseline simulation case without ice loading. The ice conditions reflecting those from Lake Huron at Port Huron and Lake Michigan at North Manitou were studied under near rated wind speed of 12 m/s for the NREL 5-MW reference turbine. Simulations were performed on ice loading models 1 through 4 and ice model 6 with their respective sub-models. The purpose of ice model 5 is to investigate ice loading on sloping structures such as ice-cones on a monopile and is not suitable for multi-membered jacketed structures like the IBGS foundation. The key response parameters from the simulations, shear forces and moments from the tower base and IBGS foundation base, were compared. Ice models 1 and 6 do not significantly affect the tower fore-aft shear and moment. However, ice model 2 (dynamic analyses), model 3 (random ice loading), and model 4 (multiple ice failure zone loading) show increased effect on the tower fore-aft shear and moment with significant effect from ice model 3.1. In general ice loading creates large reaction forces and moments at the base of the IBGS foundation; the largest occurred in model 1.1 (steady creep ice indentation loading) followed by model 3.1 (random creep ice indentation loading). In general the power production from the ice loading cases had little deviation from the baseline case without ice loading. For ultimate limit state (ULS), ice model 1.1 ice and 3.1 appear to be the ice most critical models to consider at an early stage of design. Ice model 4 is an important tool for assessing structural fatigue.« less

Modeling dynamic stall on wind turbine blades under rotationally augmented flow fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guntur, S.; Schreck, S.; Sorensen, N. N.

It is well known that airfoils under unsteady flow conditions with a periodically varying angle of attack exhibit aerodynamic characteristics different from those under steady flow conditions, a phenomenon commonly known as dynamic stall. It is also well known that the steady aerodynamic characteristics of airfoils in the inboard region of a rotating blade differ from those under steady two-dimensional (2D) flow conditions, a phenomenon commonly known as rotational augmentation. This paper presents an investigation of these two phenomena together in the inboard parts of wind turbine blades. This analysis is carried out using data from three sources: (1) themore » National Renewable Energy Laboratory’s Unsteady Aerodynamics Experiment Phase VI experimental data, including constant as well as continuously pitching blade conditions during axial operation, (2) data from unsteady Delayed Detached Eddy Simulations (DDES) carried out using the Technical University of Denmark’s in-house flow solver Ellipsys3D, and (3) data from a simplified model based on the blade element momentum method with a dynamic stall subroutine that uses rotationally augmented steady-state polars obtained from steady Phase VI experimental sequences, instead of the traditional 2D nonrotating data. The aim of this work is twofold. First, the blade loads estimated by the DDES simulations are compared to three select cases of the N sequence experimental data, which serves as a validation of the DDES method. Results show reasonable agreement between the two data in two out of three cases studied. Second, the dynamic time series of the lift and the moment polars obtained from the experiments are compared to those from the dynamic stall subroutine that uses the rotationally augmented steady polars. This allowed the differences between the stall phenomenon on the inboard parts of harmonically pitching blades on a rotating wind turbine and the classic dynamic stall representation in 2D flow to be investigated. Results from the dynamic stall subroutine indicated a good qualitative agreement between the model and the experimental data in many cases, which suggests that the current 2D dynamic stall model as used in BEM-based aeroelastic codes may provide a reasonably accurate representation of three-dimensional rotor aerodynamics when used in combination with a robust rotational augmentation model.« less

Wind turbine blade fatigue tests: lessons learned and application to SHM system development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, Stuart G.; Farinholt, Kevin M.; Jeong, Hyomi

2012-06-28

This paper presents experimental results of several structural health monitoring (SHM) methods applied to a 9-meter CX-100 wind turbine blade that underwent fatigue loading. The blade was instrumented with piezoelectric transducers, accelerometers, acoustic emission sensors, and foil strain gauges. It underwent harmonic excitation at its first natural frequency using a hydraulically actuated resonant excitation system. The blade was initially excited at 25% of its design load, and then with steadily increasing loads until it failed. Various data were collected between and during fatigue loading sessions. The data were measured over multiple frequency ranges using a variety of acquisition equipment, includingmore » off-the-shelf systems and specially designed hardware developed by the authors. Modal response, diffuse wave-field transfer functions, and ultrasonic guided wave methods were applied to assess the condition of the wind turbine blade. The piezoelectric sensors themselves were also monitored using a sensor diagnostics procedure. This paper summarizes experimental procedures and results, focusing particularly on fatigue crack detection, and concludes with considerations for implementing such damage identification systems, which will be used as a guideline for future SHM system development for operating wind turbine blades.« less

Experimental damage detection of wind turbine blade using thin film sensor array

NASA Astrophysics Data System (ADS)

Downey, Austin; Laflamme, Simon; Ubertini, Filippo; Sarkar, Partha

2017-04-01

Damage detection of wind turbine blades is difficult due to their large sizes and complex geometries. Additionally, economic restraints limit the viability of high-cost monitoring methods. While it is possible to monitor certain global signatures through modal analysis, obtaining useful measurements over a blade's surface using off-the-shelf sensing technologies is difficult and typically not economical. A solution is to deploy dedicated sensor networks fabricated from inexpensive materials and electronics. The authors have recently developed a novel large-area electronic sensor measuring strain over very large surfaces. The sensing system is analogous to a biological skin, where local strain can be monitored over a global area. In this paper, we propose the utilization of a hybrid dense sensor network of soft elastomeric capacitors to detect, localize, and quantify damage, and resistive strain gauges to augment such dense sensor network with high accuracy data at key locations. The proposed hybrid dense sensor network is installed inside a wind turbine blade model and tested in a wind tunnel to simulate an operational environment. Damage in the form of changing boundary conditions is introduced into the monitored section of the blade. Results demonstrate the ability of the hybrid dense sensor network, and associated algorithms, to detect, localize, and quantify damage.

Experimental wind tunnel study of a smart sensing skin for condition evaluation of a wind turbine blade

NASA Astrophysics Data System (ADS)

Downey, Austin; Laflamme, Simon; Ubertini, Filippo

2017-12-01

Condition evaluation of wind turbine blades is difficult due to their large size, complex geometry and lack of economic and scalable sensing technologies capable of detecting, localizing, and quantifying faults over a blade’s global area. A solution is to deploy inexpensive large area electronics over strategic areas of the monitored component, analogous to sensing skin. The authors have previously proposed a large area electronic consisting of a soft elastomeric capacitor (SEC). The SEC is highly scalable due to its low cost and ease of fabrication, and can, therefore, be used for monitoring large-scale components. A single SEC is a strain sensor that measures the additive strain over a surface. Recently, its application in a hybrid dense sensor network (HDSN) configuration has been studied, where a network of SECs is augmented with a few off-the-shelf strain gauges to measure boundary conditions and decompose the additive strain to obtain unidirectional surface strain maps. These maps can be analyzed to detect, localize, and quantify faults. In this work, we study the performance of the proposed sensing skin at conducting condition evaluation of a wind turbine blade model in an operational environment. Damage in the form of changing boundary conditions and cuts in the monitored substrate are induced into the blade. An HDSN is deployed onto the interior surface of the substrate, and the blade excited in a wind tunnel. Results demonstrate the capability of the HDSN and associated algorithms to detect, localize, and quantify damage. These results show promise for the future deployment of fully integrated sensing skins deployed inside wind turbine blades for condition evaluation.

Device for passive flow control around vertical axis marine turbine

NASA Astrophysics Data System (ADS)

Coşoiu, C. I.; Georgescu, A. M.; Degeratu, M.; Haşegan, L.; Hlevca, D.

2012-11-01

The power supplied by a turbine with the rotor placed in a free stream flow may be increased by augmenting the velocity in the rotor area. The energy of the free flow is dispersed and it may be concentrated by placing a profiled structure around the bare turbine in order to concentrate more energy in the rotor zone. At the Aerodynamic and Wind Engineering Laboratory (LAIV) of the Technical University of Civil Engineering of Bucharest (UTCB) it was developed a concentrating housing to be used for hydro or aeolian horizontal axis wind turbines, in order to increase the available energy in the active section of turbine rotor. The shape of the concentrating housing results by superposing several aero/hydro dynamic effects, the most important being the one generated by the passive flow control devices that were included in the housing structure. Those concentrating housings may be also adapted for hydro or aeolian turbines with vertical axis. The present paper details the numerical research effectuated at the LAIV to determine the performances of a vertical axis marine turbine equipped with such a concentrating device, in order to increase the energy quantity extracted from the main flow. The turbine is a Darrieus type one with three vertical straight blades, symmetric with respect to the axis of rotation, generated using a NACA4518 airfoil. The global performances of the turbine equipped with the concentrating housing were compared to the same characteristics of the bare turbine. In order to validate the numerical approach used in this paper, test cases from the literature resulting from experimental and numerical simulations for similar situations, were used.

Altitude Performance Characteristics of Tail-pipe Burner with Variable-area Exhaust Nozzle

NASA Technical Reports Server (NTRS)

Jansen, Emmert T; Thorman, H Carl

1950-01-01

An investigation was conducted in the NACA Lewis altitude wind tunnel to determine effect of altitude and flight Mach number on performance of tail-pipe burner equipped with variable-area exhaust nozzle and installed on full-scale turbojet engine. At a given flight Mach number, with constant exhaust-gas and turbine-outlet temperatures, increasing altitude lowered the tail-pipe combustion efficiency and raised the specific fuel consumption while the augmented thrust ratio remained approximately constant. At a given altitude, increasing flight Mach number raised the combustion efficiency and augmented thrust ratio and lowered the specific fuel consumption.

Towards uncovering the structure of power fluctuations of wind farms

NASA Astrophysics Data System (ADS)

Liu, Huiwen; Jin, Yaqing; Tobin, Nicolas; Chamorro, Leonardo P.

2017-12-01

The structure of the turbulence-driven power fluctuations in a wind farm is fundamentally described from basic concepts. A derived tuning-free model, supported with experiments, reveals the underlying spectral content of the power fluctuations of a wind farm. It contains two power-law trends and oscillations in the relatively low- and high-frequency ranges. The former is mostly due to the turbulent interaction between the flow and the turbine properties, whereas the latter is due to the advection between turbine pairs. The spectral wind-farm scale power fluctuations ΦP exhibit a power-law decay proportional to f-5 /3 -2 in the region corresponding to the turbulence inertial subrange and at relatively large scales, ΦP˜f-2 . Due to the advection and turbulent diffusion of large-scale structures, a spectral oscillation exists with the product of a sinusoidal behavior and an exponential decay in the frequency domain.

Towards uncovering the structure of power fluctuations of wind farms.

PubMed

Liu, Huiwen; Jin, Yaqing; Tobin, Nicolas; Chamorro, Leonardo P

2017-12-01

The structure of the turbulence-driven power fluctuations in a wind farm is fundamentally described from basic concepts. A derived tuning-free model, supported with experiments, reveals the underlying spectral content of the power fluctuations of a wind farm. It contains two power-law trends and oscillations in the relatively low- and high-frequency ranges. The former is mostly due to the turbulent interaction between the flow and the turbine properties, whereas the latter is due to the advection between turbine pairs. The spectral wind-farm scale power fluctuations Φ_{P} exhibit a power-law decay proportional to f^{-5/3-2} in the region corresponding to the turbulence inertial subrange and at relatively large scales, Φ_{P}∼f^{-2}. Due to the advection and turbulent diffusion of large-scale structures, a spectral oscillation exists with the product of a sinusoidal behavior and an exponential decay in the frequency domain.

Tail Shape Design of Boat Wind Turbines

NASA Astrophysics Data System (ADS)

Singamsitty, Venkatesh

Wind energy is a standout among the most generally utilized sustainable power source assets. A great deal of research and improvements have been happening in the wind energy field. Wind turbines are mechanical devices that convert kinetic energy into electrical power. Boat wind turbines are for the small-scale generation of electric power. In order to catch wind energy effectively, boat wind turbines need to face wind direction. Tails are used in boat wind turbines to alter the wind turbine direction and receive the variation of the incoming direction of wind. Tails are used to change the performance of boat wind turbines in an effective way. They are required to generate a quick and steady response as per change in wind direction. Tails can have various shapes, and their effects on boat wind turbines are different. However, the effects of tail shapes on the performance of boat wind turbines are not thoroughly studied yet. In this thesis, five tail shapes were studied. Their effects on boat wind turbines were investigated. The power extracted by the turbines from the air and the force acting on the boat wind turbine tail were analyzed. The results of this thesis provide a guideline of tail shape design for boat wind turbines.

The system design and performance test of hybrid vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Dwiyantoro, Bambang Arip; Suphandani, Vivien

2017-04-01

Vertical axis wind turbine is a tool that is being developed to generate energy from wind. One cause is still little use of wind energy is the design of wind turbines that are less precise. Therefore in this study will be developed the system design of hybrid vertical axis wind turbine and tested performance with experimental methods. The design of hybrid turbine based on a straight bladed Darrieus turbine along with a double step Savonius turbine. The method used to design wind turbines is by studying literature, analyzing the critical parts of a wind turbine and the structure of the optimal design. Wind turbine prototype of the optimal design characteristic tests in the wind tunnel experimentally by varying the speed of the wind. From the experimental results show that the greater the wind speed, the greater the wind turbine rotation and torque is raised. The hybrid vertical axis wind turbine has much better self-starting and better conversion efficiency.

Adaptive Control Using Residual Mode Filters Applied to Wind Turbines

NASA Technical Reports Server (NTRS)

Frost, Susan A.; Balas, Mark J.

2011-01-01

Many dynamic systems containing a large number of modes can benefit from adaptive control techniques, which are well suited to applications that have unknown parameters and poorly known operating conditions. In this paper, we focus on a model reference direct adaptive control approach that has been extended to handle adaptive rejection of persistent disturbances. We extend this adaptive control theory to accommodate problematic modal subsystems of a plant that inhibit the adaptive controller by causing the open-loop plant to be non-minimum phase. We will augment the adaptive controller using a Residual Mode Filter (RMF) to compensate for problematic modal subsystems, thereby allowing the system to satisfy the requirements for the adaptive controller to have guaranteed convergence and bounded gains. We apply these theoretical results to design an adaptive collective pitch controller for a high-fidelity simulation of a utility-scale, variable-speed wind turbine that has minimum phase zeros.

Wind Turbine Control Systems | Wind | NREL

Science.gov Websites

Turbine Control Systems Wind Turbine Control Systems Advanced wind turbine controls can reduce the loads on wind turbine components while capturing more wind energy and converting it into electricity turbines. A photo of a wind turbine against blue sky with white blades on their sides in the foreground

Data-driven RANS for simulations of large wind farms

NASA Astrophysics Data System (ADS)

Iungo, G. V.; Viola, F.; Ciri, U.; Rotea, M. A.; Leonardi, S.

2015-06-01

In the wind energy industry there is a growing need for real-time predictions of wind turbine wake flows in order to optimize power plant control and inhibit detrimental wake interactions. To this aim, a data-driven RANS approach is proposed in order to achieve very low computational costs and adequate accuracy through the data assimilation procedure. The RANS simulations are implemented with a classical Boussinesq hypothesis and a mixing length turbulence closure model, which is calibrated through the available data. High-fidelity LES simulations of a utility-scale wind turbine operating with different tip speed ratios are used as database. It is shown that the mixing length model for the RANS simulations can be calibrated accurately through the Reynolds stress of the axial and radial velocity components, and the gradient of the axial velocity in the radial direction. It is found that the mixing length is roughly invariant in the very near wake, then it increases linearly with the downstream distance in the diffusive region. The variation rate of the mixing length in the downstream direction is proposed as a criterion to detect the transition between near wake and transition region of a wind turbine wake. Finally, RANS simulations were performed with the calibrated mixing length model, and a good agreement with the LES simulations is observed.

Potential of neuro-fuzzy methodology to estimate noise level of wind turbines

NASA Astrophysics Data System (ADS)

Nikolić, Vlastimir; Petković, Dalibor; Por, Lip Yee; Shamshirband, Shahaboddin; Zamani, Mazdak; Ćojbašić, Žarko; Motamedi, Shervin

2016-01-01

Wind turbines noise effect became large problem because of increasing of wind farms numbers since renewable energy becomes the most influential energy sources. However, wind turbine noise generation and propagation is not understandable in all aspects. Mechanical noise of wind turbines can be ignored since aerodynamic noise of wind turbine blades is the main source of the noise generation. Numerical simulations of the noise effects of the wind turbine can be very challenging task. Therefore in this article soft computing method is used to evaluate noise level of wind turbines. The main goal of the study is to estimate wind turbine noise in regard of wind speed at different heights and for different sound frequency. Adaptive neuro-fuzzy inference system (ANFIS) is used to estimate the wind turbine noise levels.

Bistable flow occurrence in the 2D model of a steam turbine valve

NASA Astrophysics Data System (ADS)

Pavel, Procházka; Václav, Uruba

2017-09-01

The internal flow inside a steam turbine valve was investigated experimentally using PIV measurement. The valve model was proposed to be two-dimensional. The model was connected to the blow-down wind tunnel. The flow conditions were set by the different position of the valve plug. Several angles of the diffuser by diverse radii were investigated concerning flow separation and flow dynamics. It was found that the flow takes one of two possible bistable modes. The first regime is characterized by a massive flow separation just at the beginning of the diffuser section on the one side. The second regime is axisymmetric and the flow separation is not detected at all.

CFD analysis of a Darrieus wind turbine

NASA Astrophysics Data System (ADS)

Niculescu, M. L.; Cojocaru, M. G.; Pricop, M. V.; Pepelea, D.; Dumitrache, A.; Crunteanu, D. E.

2017-07-01

The Darrieus wind turbine has some advantages over the horizontal-axis wind turbine. Firstly, its tip speed ratio is lower than that of the horizontal-axis wind turbine and, therefore, its noise is smaller, privileging their placement near populated areas. Secondly, the Darrieus wind turbine does needs no orientation mechanism with respect to wind direction in contrast to the horizontal-axis wind turbine. However, the efficiency of the Darrieus wind turbine is lower than that of the horizontal-axis wind turbine since its aerodynamics is much more complex. With the advances in computational fluids and computers, it is possible to simulate the Darrieus wind turbine more accurately to understand better its aerodynamics. For these reasons, the present papers deals with the computational aerodynamics of a Darrieus wind turbine applying the state of the art of CFD methods (anisotropic turbulence models, transition from laminar to turbulent, scale adaptive simulation) to better understand its unsteady behavior.

Research Needs for Wind Resource Characterization

NASA Astrophysics Data System (ADS)

Schreck, S. J.; Lundquist, J. K.; Shaw, W. J.

2008-12-01

Currently, wind energy provides about 1 percent of U.S. electricity generation. A recent analysis by DOE, NREL, and AWEA showed the feasibility of expanding U.S. wind energy capacity to 20 percent, comprising approximately 300 gigawatts. Though not a prediction of the future, this represents a plausible scenario for U.S. wind energy. To exploit these opportunities, a workshop on Research Needs for Wind Resource Characterization was held during January 2008. This event was organized on behalf of two DOE organizations; the Office of Biological and Environmental Research and the Office of Energy Efficiency and Renewable Energy. Over 120 atmospheric science and wind energy researchers attended the workshop from industry, academia, and federal laboratories in North America and Europe. Attendees identified problems that could impede achieving the 20 percent wind scenario and formulated research recommendations to attack these problems. Findings were structured into four focus areas: 1) Turbine Dynamics, 2) Micrositing and Array Effects, 3) Mesoscale Processes, and 4) Climate Effects. In the Turbine Dynamics area, detailed characterizations of inflows and turbine flow fields were deemed crucial to attaining accuracy levels in aerodynamics loads required for future designs. To address the complexities inherent in this area, an incremental approach involving hierarchical computational modeling and detailed measurements was recommended. Also recommended was work to model extreme and anomalous atmospheric inflow events and aerostructural responses of turbines to these events. The Micrositing and Array Effects area considered improved wake models important for large, multiple row wind plants. Planetary boundary layer research was deemed necessary to accurately determine inflow characteristics in the presence of atmospheric stability effects and complex surface characteristics. Finally, a need was identified to acquire and exploit large wind inflow data sets, covering heights to 200 meters and encompassing spatial and temporal resolution ranges unique to wind energy. The Mesoscale Processes area deemed improved understanding of mesoscale and local flows crucial to providing enhanced model outputs for wind energy production forecasts and wind plant siting. Modeling approaches need to be developed to resolve spatial scales in the 100 to 1000 meter range, a notable gap in current capabilities. Validation of these models will require new instruments and observational strategies, including augmented analyses of existing measurements. In the Climate Effects area, research was recommended to understand historical trends in wind resource variability. This was considered a prerequisite for improved predictions of future wind climate and resources, which would enable reliable wind resource estimation for future planning. Participants also considered it important to characterize interactions between wind plants and climates through modeling and observations that suitably emphasize atmospheric boundary layer dynamics. High-penetration wind energy deployment represents a crucial and attainable U.S. strategic objective. Achieving the 20 percent wind scenario will require an unprecedented ability for characterizing large wind turbines arrayed in gigawatt wind plants and extracting elevated energy levels from the atmosphere. DOE national laboratories, with industry and academia, represents a formidable capability for attaining these objectives.

Wind Energy Modeling and Simulation | Wind | NREL

Science.gov Websites

Wind Energy Modeling and Simulation Wind Turbine Modeling and Simulation Wind turbines are unique wind turbines. It enables the analysis of a range of wind turbine configurations, including: Two- or (SOWFA) employs computational fluid dynamics to allow users to investigate wind turbine and wind power

Computational examination of utility scale wind turbine wake interactions

DOE PAGES

Okosun, Tyamo; Zhou, Chenn Q.

2015-07-14

We performed numerical simulations of small, utility scale wind turbine groupings to determine how wakes generated by upstream turbines affect the performance of the small turbine group as a whole. Specifically, various wind turbine arrangements were simulated to better understand how turbine location influences small group wake interactions. The minimization of power losses due to wake interactions certainly plays a significant role in the optimization of wind farms. Since wind turbines extract kinetic energy from the wind, the air passing through a wind turbine decreases in velocity, and turbines downstream of the initial turbine experience flows of lower energy, resultingmore » in reduced power output. Our study proposes two arrangements of turbines that could generate more power by exploiting the momentum of the wind to increase velocity at downstream turbines, while maintaining low wake interactions at the same time. Furthermore, simulations using Computational Fluid Dynamics are used to obtain results much more quickly than methods requiring wind tunnel models or a large scale experimental test.« less

Scanning of wind turbine upwind conditions: numerical algorithm and first applications

NASA Astrophysics Data System (ADS)

Calaf, Marc; Cortina, Gerard; Sharma, Varun; Parlange, Marc B.

2014-11-01

Wind turbines still obtain in-situ meteorological information by means of traditional wind vane and cup anemometers installed at the turbine's nacelle, right behind the blades. This has two important drawbacks: 1-turbine misalignment with the mean wind direction is common and energy losses are experienced; 2-the near-blade monitoring does not provide any time to readjust the profile of the wind turbine to incoming turbulence gusts. A solution is to install wind Lidar devices on the turbine's nacelle. This technique is currently under development as an alternative to traditional in-situ wind anemometry because it can measure the wind vector at substantial distances upwind. However, at what upwind distance should they interrogate the atmosphere? A new flexible wind turbine algorithm for large eddy simulations of wind farms that allows answering this question, will be presented. The new wind turbine algorithm timely corrects the turbines' yaw misalignment with the changing wind. The upwind scanning flexibility of the algorithm also allows to track the wind vector and turbulent kinetic energy as they approach the wind turbine's rotor blades. Results will illustrate the spatiotemporal evolution of the wind vector and the turbulent kinetic energy as the incoming flow approaches the wind turbine under different atmospheric stability conditions. Results will also show that the available atmospheric wind power is larger during daytime periods at the cost of an increased variance.

Use of 3D Printing for Custom Wind Tunnel Fabrication

NASA Astrophysics Data System (ADS)

Gagorik, Paul; Bates, Zachary; Issakhanian, Emin

2016-11-01

Small-scale wind tunnels for the most part are fairly simple to produce with standard building equipment. However, the intricate bell housing and inlet shape of an Eiffel type wind tunnel, as well as the transition from diffuser to fan in a rectangular tunnel can present design and construction obstacles. With the help of 3D printing, these shapes can be custom designed in CAD models and printed in the lab at very low cost. The undergraduate team at Loyola Marymount University has built a custom benchtop tunnel for gas turbine film cooling experiments. 3D printing is combined with conventional construction methods to build the tunnel. 3D printing is also used to build the custom tunnel floor and interchangeable experimental pieces for various experimental shapes. This simple and low-cost tunnel is a custom solution for specific engineering experiments for gas turbine technology research.

Investigation of turbine ventilator performance after added wind cup for room exhaust air applications

NASA Astrophysics Data System (ADS)

Harun, D.; Zulfadhli; Akhyar, H.

2018-05-01

The turbine ventilator is a wind turbine with a vertical axis that has a combined function of the wind turbine and a suction fan. In this study, the turbine ventilator modified by adding a wind cup on the top (cap) turbine ventilator. The purpose of this experiment is to investigated the effect of the addition of wind cup on the turbine ventilator. Turbine ventilator used is type v30 and wind cup with diameter 77 mm. The experiment was conducted using a triangular pentagon model space chamber which was cut off to place the ventilator turbine ventilation cup with a volume of 0.983 m3 (equivalent to 1 mm3). The results of this study indicate that at an average wind speed of 1.8 m/s, the rotation of the turbine produced without a wind cup is 60.6 rpm while with the addition of a wind cup in the turbine ventilator is 69 rpm. The average increase of rotation turbine after added win cup is 8.4 rpm and the efficiency improvement of turbine ventilator is 1.7 %.

An integrated modeling method for wind turbines

NASA Astrophysics Data System (ADS)

Fadaeinedjad, Roohollah

To study the interaction of the electrical, mechanical, and aerodynamic aspects of a wind turbine, a detailed model that considers all these aspects must be used. A drawback of many studies in the area of wind turbine simulation is that either a very simple mechanical model is used with a detailed electrical model, or vice versa. Hence the interactions between electrical and mechanical aspects of wind turbine operation are not accurately taken into account. In this research, it will be shown that a combination of different simulation packages, namely TurbSim, FAST, and Simulink can be used to model the aerodynamic, mechanical, and electrical aspects of a wind turbine in detail. In this thesis, after a review of some wind turbine concepts and software tools, a simulation structure is proposed for studying wind turbines that integrates the mechanical and electrical components of a wind energy conversion device. Based on the simulation structure, a comprehensive model for a three-bladed variable speed wind turbine with doubly-fed induction generator is developed. Using the model, the impact of a voltage sag on the wind turbine tower vibration is investigated under various operating conditions such as power system short circuit level, mechanical parameters, and wind turbine operating conditions. It is shown how an electrical disturbance can cause more sustainable tower vibrations under high speed and turbulent wind conditions, which may disrupt the operation of pitch control system. A similar simulation structure is used to model a two-bladed fixed speed wind turbine with an induction generator. An extension of the concept is introduced by adding a diesel generator system. The model is utilized to study the impact of the aeroelastic aspects of wind turbine (i.e. tower shadow, wind shears, yaw error, turbulence, and mechanical vibrations) on the power quality of a stand-alone wind-diesel system. Furthermore, an IEEE standard flickermeter model is implemented in a Simulink environment to study the flicker contribution of the wind turbine in the wind-diesel system. By using a new wind power plant representation method, a large wind farm (consisting of 96 fixed speed wind turbines) is modelled to study the power quality of wind power system. The flicker contribution of wind farm is also studied with different wind turbine numbers, using the flickermeter model. Keywords. Simulink, FAST, TurbSim, AreoDyn, wind energy, doubly-fed induction generator, variable speed wind turbine, voltage sag, tower vibration, power quality, flicker, fixed speed wind turbine, wind shear, tower shadow, and yaw error.

On the Effect of Offshore Wind Parks on Ocean Dynamics

NASA Astrophysics Data System (ADS)

Ludewig, E.; Pohlmann, T.

2012-12-01

Nowadays renewable energy resources play a key role in the energy supply discussion and especially an increasingly interest in wind energy induces intensified installations of wind parks. At this offshore wind energy gains in popularity in the course of higher and more consistent energy availability than over land. For example Germany's government adopted a national interurban offshore wind energy program comprising the construction of hundreds of wind turbines within Germany's Exclusive Economic Zone to ensure up to 50% of Germany's renewable energy supply. The large number of installation in coastal regions asks for analyzing the impact of offshore wind parks (OWPs) on the atmosphere and the ocean. As known from literature such wind parks excite also-called wake-effect and such an influence on the wind field in turn affects ocean circulation. To cover OWP's impact on ocean dynamics we evaluate model simulations using the Hamburg Shelf-Ocean-Model (HAMSOM). All simulations were driven with a wind forcing produced by the Mesoscale Atmosphere Model of the Hamburg University (METRAS) which has implemented wind turbines. Wind forcing data were generated in collaboration with and by courtesy of the Meteorological Institute of the University of Hamburg, Department Technical Meteorology, Numeric Modeling-METRAS. To evaluate dynamical changes forced by the OWP's wind wake-effect we did a sensitivity study with a theoretical setup of a virtual ocean of 60m depth with a flat bottom and a temperature and salinity stratification according to common North Sea's conditions. Here our results show that already a small OWP of 12 wind turbines, placed in an area of 4 km^2, lead to a complex change in ocean dynamics. Due to the wake-effect zones of upwelling and downwelling are formed within a minute after turning-on wind turbines. The evolving vertical cells have a size of around 15x15 kilometers with a vertical velocity in order of 10^-2 mm/sec influencing the dynamic of an area being hundred times bigger than the wind park itself. The emerged vertical structure is generated due to a newly created geostrophic balance resulting in a redistribution of the ocean mass field. A number of additional upwelling and downwelling cells around the wind park support an intensified vertical dispersion through all layers and incline the thermocline which also influences the lower levels. The disturbances of mass show a dipole structure across the main wind direction with a maximum change in thermocline depth of some meters close to the OWP. Diffusion, mostly driven by direct wind induced surface shear is also modified by the wind turbines and supports a further modification of the vertical patterns. Considering that wind turbines operate only in a special window of wind speed, i.e. wind turbines will stop in case of too weak or too strong wind speeds as well as in case of technical issues, the averaged dimension and intensity of occurring vertical cells depend on the number of rotors and expected wind speeds. Finally we will focus on scenario runs for the North Sea under fully realistic conditions to estimate possible changes in ocean dynamics due to OWPs in future and these results will be further used for process analyzes of the ecosystem. If we assume a continuous operation of North Sea's OWPs in future we expect a fundamental constant change in ocean dynamics and moreover in the ecosystem in its vicinity.

Review of fluid and control technology of hydraulic wind turbines

NASA Astrophysics Data System (ADS)

Cai, Maolin; Wang, Yixuan; Jiao, Zongxia; Shi, Yan

2017-09-01

This study examines the development of the fluid and control technology of hydraulic wind turbines. The current state of hydraulic wind turbines as a new technology is described, and its basic fluid model and typical control method are expounded by comparing various study results. Finally, the advantages of hydraulic wind turbines are enumerated. Hydraulic wind turbines are expected to become the main development direction of wind turbines.

An experimental investigation on wind turbine aeromechanics and wake interferences among multiple wind turbines

NASA Astrophysics Data System (ADS)

Ozbay, Ahmet

A comprehensive experimental study was conducted to investigate wind turbine aeromechanics and wake interferences among multiple wind turbines sited in onshore and offshore wind farms. The experiments were carried out in a large-scale Aerodynamic/Atmospheric Boundary Layer (AABL) Wind Tunnel available at Iowa State University. An array of scaled three-blade Horizontal Axial Wind Turbine (HAWT) models were placed in atmospheric boundary layer winds with different mean and turbulence characteristics to simulate the situations in onshore and offshore wind farms. The effects of the important design parameters for wind farm layout optimization, which include the mean and turbulence characteristics of the oncoming surface winds, the yaw angles of the turbines with respect to the oncoming surface winds, the array spacing and layout pattern, and the terrain topology of wind farms on the turbine performances (i.e., both power output and dynamic wind loadings) and the wake interferences among multiple wind turbines, were assessed in detail. The aeromechanic performance and near wake characteristics of a novel dual-rotor wind turbine (DRWT) design with co-rotating or counter-rotating configuration were also investigated, in comparison to a conventional single rotor wind turbine (SRWT). During the experiments, in addition to measuring dynamic wind loads (both forces and moments) and the power outputs of the scaled turbine models, a high-resolution Particle Image Velocity (PIV) system was used to conduct detailed flow field measurements (i.e., both free-run and phase-locked flow fields measurements) to reveal the transient behavior of the unsteady wake vortices and turbulent flow structures behind wind turbines and to quantify the characteristics of the wake interferences among the wind turbines sited in non-homogenous surface winds. A miniature cobra anemometer was also used to provide high-temporal-resolution data at points of interest to supplement the full field PIV measurement results. The detailed flow field measurements are correlated with the dynamic wind loads and power output measurements to elucidate underlying physics in order to gain further insight into the characteristics of the power generation performance, dynamic wind loads and wake interferences of the wind turbines for higher total power yield and better durability of the wind turbines sited in atmospheric boundary layer (ABL) winds.

Wind farm electrical system

DOEpatents

Erdman, William L.; Lettenmaier, Terry M.

2006-07-04

An approach to wind farm design using variable speed wind turbines with low pulse number electrical output. The output of multiple wind turbines are aggregated to create a high pulse number electrical output at a point of common coupling with a utility grid network. Power quality at each individual wind turbine falls short of utility standards, but the aggregated output at the point of common coupling is within acceptable tolerances for utility power quality. The approach for aggregating low pulse number electrical output from multiple wind turbines relies upon a pad mounted transformer at each wind turbine that performs phase multiplication on the output of each wind turbine. Phase multiplication converts a modified square wave from the wind turbine into a 6 pulse output. Phase shifting of the 6 pulse output from each wind turbine allows the aggregated output of multiple wind turbines to be a 24 pulse approximation of a sine wave. Additional filtering and VAR control is embedded within the wind farm to take advantage of the wind farm's electrical impedence characteristics to further enhance power quality at the point of common coupling.

Wind Turbine Research Validation | Wind | NREL

Science.gov Websites

Wind Turbine Research Validation Wind Turbine Research Validation Photo of a large wind turbine operators with turbine and component research validation that ensures performance and reliability. Prototype research is especially important to capture manufacturing flaws. The NWTC staff conducts research on

Performance characteristics of aerodynamically optimum turbines for wind energy generators

NASA Technical Reports Server (NTRS)

Rohrbach, C.; Worobel, R.

1975-01-01

This paper presents a brief discussion of the aerodynamic methodology for wind energy generator turbines, an approach to the design of aerodynamically optimum wind turbines covering a broad range of design parameters, some insight on the effect on performance of nonoptimum blade shapes which may represent lower fabrication costs, the annual wind turbine energy for a family of optimum wind turbines, and areas of needed research. On the basis of the investigation, it is concluded that optimum wind turbines show high performance over a wide range of design velocity ratios; that structural requirements impose constraints on blade geometry; that variable pitch wind turbines provide excellent power regulation and that annual energy output is insensitive to design rpm and solidity of optimum wind turbines.

77 FR 22569 - Interconnection of the Grande Prairie Wind Farm, Holt County, NE

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-16

... operations and maintenance building. Grande Prairie Wind would site wind turbine generators and supporting... wind turbines. Permanent disturbance for each wind turbine generator location would be approximately 0.25 acres. Grande Prairie Wind is considering a variety of wind turbine generator types, with...

Net energy payback and CO2 emissions from three midwestern wind farms: An update

USGS Publications Warehouse

White, S.W.

2006-01-01

This paper updates a life-cycle net energy analysis and carbon dioxide emissions analysis of three Midwestern utility-scale wind systems. Both the Energy Payback Ratio (EPR) and CO2 analysis results provide useful data for policy discussions regarding an efficient and low-carbon energy mix. The EPR is the amount of electrical energy produced for the lifetime of the power plant divided by the total amount of energy required to procure and transport the materials, build, operate, and decommission the power plants. The CO2 analysis for each power plant was calculated from the life-cycle energy input data. A previous study also analyzed coal and nuclear fission power plants. At the time of that study, two of the three wind systems had less than a full year of generation data to project the life-cycle energy production. This study updates the analysis of three wind systems with an additional four to eight years of operating data. The EPR for the utility-scale wind systems ranges from a low of 11 for a two-turbine system in Wisconsin to 28 for a 143-turbine system in southwestern Minnesota. The EPR is 11 for coal, 25 for fission with gas centrifuge enriched uranium and 7 for gaseous diffusion enriched uranium. The normalized CO2 emissions, in tonnes of CO2 per GW eh, ranges from 14 to 33 for the wind systems, 974 for coal, and 10 and 34 for nuclear fission using gas centrifuge and gaseous diffusion enriched uranium, respectively. ?? Springer Science+Business Media, LLC 2007.

Effects of setting angle and chord length on performance of four blades bionic wind turbine

NASA Astrophysics Data System (ADS)

Yang, Z. X.; Li, G. S.; Song, L.; Bai, Y. F.

2017-11-01

With the energy crisis and the increasing environmental pollution, more and more efforts have been made about wind power development. In this paper, a four blades bionic wind turbine was proposed, and the outline of wind turbine was constructed by the fitted curve. This paper attempted to research the effects of setting angle and chord length on performance of four blades bionic wind turbine by computational fluid dynamics (CFD) simulation. The results showed that the setting angle and chord length of the bionic wind turbine has some significant effects on the efficiency of the wind turbine, and within the range of wind speed from 7 m/s to 15 m/s, the wind turbine achieved maximum efficiency when the setting angle is 31 degree and the chord length is 125 mm. The conclusion will work as a guideline for the improvement of wind turbine design

Methods and apparatus for reducing peak wind turbine loads

DOEpatents

Moroz, Emilian Mieczyslaw

2007-02-13

A method for reducing peak loads of wind turbines in a changing wind environment includes measuring or estimating an instantaneous wind speed and direction at the wind turbine and determining a yaw error of the wind turbine relative to the measured instantaneous wind direction. The method further includes comparing the yaw error to a yaw error trigger that has different values at different wind speeds and shutting down the wind turbine when the yaw error exceeds the yaw error trigger corresponding to the measured or estimated instantaneous wind speed.

First International Workshop on Grid Simulator Testing of Wind Turbine

Science.gov Websites

of Wind Turbine Drivetrains First International Workshop on Grid Simulator Testing of Wind Turbine Wind Turbine Drivetrains June 13-14, 2013, at the National Wind Technology Center near Boulder apparatuses involved in grid compliance testing of utility-scale wind turbine generators. This includes both

A wind turbine hybrid simulation framework considering aeroelastic effects

NASA Astrophysics Data System (ADS)

Song, Wei; Su, Weihua

2015-04-01

In performing an effective structural analysis for wind turbine, the simulation of turbine aerodynamic loads is of great importance. The interaction between the wake flow and the blades may impact turbine blades loading condition, energy yield and operational behavior. Direct experimental measurement of wind flow field and wind profiles around wind turbines is very helpful to support the wind turbine design. However, with the growth of the size of wind turbines for higher energy output, it is not convenient to obtain all the desired data in wind-tunnel and field tests. In this paper, firstly the modeling of dynamic responses of large-span wind turbine blades will consider nonlinear aeroelastic effects. A strain-based geometrically nonlinear beam formulation will be used for the basic structural dynamic modeling, which will be coupled with unsteady aerodynamic equations and rigid-body rotations of the rotor. Full wind turbines can be modeled by using the multi-connected beams. Then, a hybrid simulation experimental framework is proposed to potentially address this issue. The aerodynamic-dominant components, such as the turbine blades and rotor, are simulated as numerical components using the nonlinear aeroelastic model; while the turbine tower, where the collapse of failure may occur under high level of wind load, is simulated separately as the physical component. With the proposed framework, dynamic behavior of NREL's 5MW wind turbine blades will be studied and correlated with available numerical data. The current work will be the basis of the authors' further studies on flow control and hazard mitigation on wind turbine blades and towers.

Doubly fed induction generator wind turbines with fuzzy controller: a survey.

PubMed

Sathiyanarayanan, J S; Kumar, A Senthil

2014-01-01

Wind energy is one of the extraordinary sources of renewable energy due to its clean character and free availability. With the increasing wind power penetration, the wind farms are directly influencing the power systems. The majority of wind farms are using variable speed wind turbines equipped with doubly fed induction generators (DFIG) due to their advantages over other wind turbine generators (WTGs). Therefore, the analysis of wind power dynamics with the DFIG wind turbines has become a very important research issue, especially during transient faults. This paper presents fuzzy logic control of doubly fed induction generator (DFIG) wind turbine in a sample power system. Fuzzy logic controller is applied to rotor side converter for active power control and voltage regulation of wind turbine.

Experimental investigation on performance of crossflow wind turbine as effect of blades number

NASA Astrophysics Data System (ADS)

Kurniawati, Diniar Mungil; Tjahjana, Dominicus Danardono Dwi Prija; Santoso, Budi

2018-02-01

Urban living is one of the areas with large electrical power consumption that requires a power supply that is more than rural areas. The number of multi-storey buildings such as offices, hotels and several other buildings that caused electricity power consumption in urban living is very high. Therefore, energy alternative is needed to replace the electricity power consumption from government. One of the utilization of renewable energy in accordance with these conditions is the installation of wind turbines. One type of wind turbine that is now widely studied is a crossflow wind turbines. Crossflow wind turbine is one of vertical axis wind turbine which has good self starting at low wind speed condition. Therefore, the turbine design parameter is necessary to know in order to improve turbine performance. One of wind turbine performance parameter is blades number. The main purpose of this research to investigate the effect of blades number on crossflow wind turbine performance. The design of turbine was 0.4 × 0.4 m2 tested by experimental method with configuration on three kinds of blades number were 8,16 and 20. The turbine investigated at low wind speed on 2 - 5 m/s. The result showed that best performance on 16 blade number.

Wind Turbine Contingency Control Through Generator De-Rating

NASA Technical Reports Server (NTRS)

Frost, Susan; Goebel, Kai; Balas, Mark

2013-01-01

Maximizing turbine up-time and reducing maintenance costs are key technology drivers for wind turbine operators. Components within wind turbines are subject to considerable stresses due to unpredictable environmental conditions resulting from rapidly changing local dynamics. In that context, systems health management has the aim to assess the state-of-health of components within a wind turbine, to estimate remaining life, and to aid in autonomous decision-making to minimize damage to the turbine. Advanced contingency control is one way to enable autonomous decision-making by providing the mechanism to enable safe and efficient turbine operation. The work reported herein explores the integration of condition monitoring of wind turbines with contingency control to balance the trade-offs between maintaining system health and energy capture. The contingency control involves de-rating the generator operating point to achieve reduced loads on the wind turbine. Results are demonstrated using a high fidelity simulator of a utility-scale wind turbine.

Mixer-Ejector Wind Turbine: Breakthrough High Efficiency Shrouded Wind Turbine

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-02-22

Broad Funding Opportunity Announcement Project: FloDesign Wind Turbine’s innovative wind turbine, inspired by the design of jet engines, could deliver 300% more power than existing wind turbines of the same rotor diameter by extracting more energy over a larger area. FloDesign Wind Turbine’s unique shrouded design expands the wind capture area, and the mixing vortex downstream allows more energy to flow through the rotor without stalling the turbine. The unique rotor and shrouded design also provide significant opportunity for mass production and simplified assembly, enabling mid-scale turbines (approximately 100 kW) to produce power at a cost that is comparable tomore » larger-scale conventional turbines.« less

Doubly Fed Induction Generator Wind Turbines with Fuzzy Controller: A Survey

PubMed Central

Sathiyanarayanan, J. S.; Senthil Kumar, A.

2014-01-01

Wind energy is one of the extraordinary sources of renewable energy due to its clean character and free availability. With the increasing wind power penetration, the wind farms are directly influencing the power systems. The majority of wind farms are using variable speed wind turbines equipped with doubly fed induction generators (DFIG) due to their advantages over other wind turbine generators (WTGs). Therefore, the analysis of wind power dynamics with the DFIG wind turbines has become a very important research issue, especially during transient faults. This paper presents fuzzy logic control of doubly fed induction generator (DFIG) wind turbine in a sample power system. Fuzzy logic controller is applied to rotor side converter for active power control and voltage regulation of wind turbine. PMID:25028677

NWTC Aerodynamics Studies Improve Energy Capture and Lower Costs of Wind-Generated Electricity

DOE Office of Scientific and Technical Information (OSTI.GOV)

2015-08-01

Researchers at the National Wind Technology Center (NWTC) at the National Renewable Energy Laboratory (NREL) have expanded wind turbine aerodynamic research from blade and rotor aerodynamics to wind plant and atmospheric inflow effects. The energy capture from wind plants is dependent on all of these aerodynamic interactions. Research at the NWTC is crucial to understanding how wind turbines function in large, multiple-row wind plants. These conditions impact the cumulative fatigue damage of turbine structural components that ultimately effect the useful lifetime of wind turbines. This work also is essential for understanding and maximizing turbine and wind plant energy production. Bothmore » turbine lifetime and wind plant energy production are key determinants of the cost of wind-generated electricity.« less

Materials for Wind Turbine Blades: An Overview.

PubMed

Mishnaevsky, Leon; Branner, Kim; Petersen, Helga Nørgaard; Beauson, Justine; McGugan, Malcolm; Sørensen, Bent F

2017-11-09

A short overview of composite materials for wind turbine applications is presented here. Requirements toward the wind turbine materials, loads, as well as available materials are reviewed. Apart from the traditional composites for wind turbine blades (glass fibers/epoxy matrix composites), natural composites, hybrid and nanoengineered composites are discussed. Manufacturing technologies for wind turbine composites, as well their testing and modelling approaches are reviewed.

77 FR 74865 - Notice of Availability of the Final Environmental Impact Statement for the Searchlight Wind...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-18

... Record of Decision. The proposed wind turbines located on the SWE project would be up to 262-feet tall... up to 415 feet. In addition to the wind turbines, the proposed project would require the construction... turbine layout, an 87 wind turbine layout, and a no-action alternative. The 87 wind turbine alternative is...

Tacholess order-tracking approach for wind turbine gearbox fault detection

NASA Astrophysics Data System (ADS)

Wang, Yi; Xie, Yong; Xu, Guanghua; Zhang, Sicong; Hou, Chenggang

2017-09-01

Monitoring of wind turbines under variable-speed operating conditions has become an important issue in recent years. The gearbox of a wind turbine is the most important transmission unit; it generally exhibits complex vibration signatures due to random variations in operating conditions. Spectral analysis is one of the main approaches in vibration signal processing. However, spectral analysis is based on a stationary assumption and thus inapplicable to the fault diagnosis of wind turbines under variable-speed operating conditions. This constraint limits the application of spectral analysis to wind turbine diagnosis in industrial applications. Although order-tracking methods have been proposed for wind turbine fault detection in recent years, current methods are only applicable to cases in which the instantaneous shaft phase is available. For wind turbines with limited structural spaces, collecting phase signals with tachometers or encoders is difficult. In this study, a tacholess order-tracking method for wind turbines is proposed to overcome the limitations of traditional techniques. The proposed method extracts the instantaneous phase from the vibration signal, resamples the signal at equiangular increments, and calculates the order spectrum for wind turbine fault identification. The effectiveness of the proposed method is experimentally validated with the vibration signals of wind turbines.

Small Horizontal Axis Wind Turbine under High Speed Operation: Study of Power Evaluation

NASA Astrophysics Data System (ADS)

Moh. M. Saad, Magedi; Mohd, Sofian Bin; Zulkafli, Mohd Fadhli Bin; Abdullah, Aslam Bin; Rahim, Mohammad Zulafif Bin; Subari, Zulkhairi Bin; Rosly, Nurhayati Binti

2017-10-01

Mechanical energy is produced through the rotation of wind turbine blades by air that convert the mechanical energy into electrical energy. Wind turbines are usually designed to be use for particular applications and design characteristics may vary depending on the area of use. The variety of applications is reflected on the size of turbines and their infrastructures, however, performance enhancement of wind turbine may start by analyzing the small horizontal axis wind turbine (SHAWT) under high wind speed operation. This paper analyzes the implementations of SHAWT turbines and investigates their performance in both simulation and real life. Depending on the real structure of the rotor geometry and aerodynamic test, the power performance of the SHAWT was simulated using ANSYS-FLUENT software at different wind speed up to 33.33 m/s (120km/h) in order to numerically investigate the actual turbine operation. Dynamic mesh and user define function (UDF) was used for revolving the rotor turbine via wind. Simulation results were further validated by experimental data and hence good matching was yielded. And for reducing the energy producing cost, car alternator was formed to be used as a small horizontal wind turbine. As a result, alternator-based turbine system was found to be a low-cost solution for exploitation of wind energy.

Design and aero-acoustic analysis of a counter-rotating wind turbine

NASA Astrophysics Data System (ADS)

Agrawal, Vineesh V.

Wind turbines have become an integral part of the energy business because they are one of the most economical and reliable sources of renewable energy. Conventional wind turbines are capable of capturing less than half of the energy present in the wind. Hence, to make the wind turbines more efficient, it is important to increase their performance. A horizontal axis wind turbine with multiple rotors is one concept that can achieve a higher power conversion rate. Also, a concern for wind energy is the noise generated by wind turbines. Hence, an investigation into the acoustic behavior of a multi-rotor horizontal axis wind turbine is required. In response to the need of a wind turbine design with higher power coefficient, a unique design of a counter-rotating horizontal axis wind turbine (CR-HAWT) is proposed. The Blade Element Momentum (BEM) theory is used to aerodynamically design the blades of the two rotors. Modifications are made to the BEM theory to accommodate the interaction of the two rotors. The tower effect on the noise generation of the downwind rotor is investigated. Predictions are made for the total noise generated by the wind turbine at its design operating conditions. A total power coefficient of 65.2% is predicted for the proposed CR-HAWT design. A low tip speed ratio is chosen to minimize the noise generation. The aeroacoustic analysis of the CR-HAWT shows that the noise generated at its design operating conditions is within an acceptable range. Thus, the CR-HAWT is predicted to be a quiet wind turbine with a high power coefficient, making it highly desirable for small wind turbine applications.

Health Effects Related to Wind Turbine Noise Exposure: A Systematic Review

PubMed Central

Schmidt, Jesper Hvass; Klokker, Mads

2014-01-01

Background Wind turbine noise exposure and suspected health-related effects thereof have attracted substantial attention. Various symptoms such as sleep-related problems, headache, tinnitus and vertigo have been described by subjects suspected of having been exposed to wind turbine noise. Objective This review was conducted systematically with the purpose of identifying any reported associations between wind turbine noise exposure and suspected health-related effects. Data Sources A search of the scientific literature concerning the health-related effects of wind turbine noise was conducted on PubMed, Web of Science, Google Scholar and various other Internet sources. Study Eligibility Criteria All studies investigating suspected health-related outcomes associated with wind turbine noise exposure were included. Results Wind turbines emit noise, including low-frequency noise, which decreases incrementally with increases in distance from the wind turbines. Likewise, evidence of a dose-response relationship between wind turbine noise linked to noise annoyance, sleep disturbance and possibly even psychological distress was present in the literature. Currently, there is no further existing statistically-significant evidence indicating any association between wind turbine noise exposure and tinnitus, hearing loss, vertigo or headache. Limitations Selection bias and information bias of differing magnitudes were found to be present in all current studies investigating wind turbine noise exposure and adverse health effects. Only articles published in English, German or Scandinavian languages were reviewed. Conclusions Exposure to wind turbines does seem to increase the risk of annoyance and self-reported sleep disturbance in a dose-response relationship. There appears, though, to be a tolerable level of around LAeq of 35 dB. Of the many other claimed health effects of wind turbine noise exposure reported in the literature, however, no conclusive evidence could be found. Future studies should focus on investigations aimed at objectively demonstrating whether or not measureable health-related outcomes can be proven to fluctuate depending on exposure to wind turbines. PMID:25474326

Health effects related to wind turbine noise exposure: a systematic review.

PubMed

Schmidt, Jesper Hvass; Klokker, Mads

2014-01-01

Wind turbine noise exposure and suspected health-related effects thereof have attracted substantial attention. Various symptoms such as sleep-related problems, headache, tinnitus and vertigo have been described by subjects suspected of having been exposed to wind turbine noise. This review was conducted systematically with the purpose of identifying any reported associations between wind turbine noise exposure and suspected health-related effects. A search of the scientific literature concerning the health-related effects of wind turbine noise was conducted on PubMed, Web of Science, Google Scholar and various other Internet sources. All studies investigating suspected health-related outcomes associated with wind turbine noise exposure were included. Wind turbines emit noise, including low-frequency noise, which decreases incrementally with increases in distance from the wind turbines. Likewise, evidence of a dose-response relationship between wind turbine noise linked to noise annoyance, sleep disturbance and possibly even psychological distress was present in the literature. Currently, there is no further existing statistically-significant evidence indicating any association between wind turbine noise exposure and tinnitus, hearing loss, vertigo or headache. Selection bias and information bias of differing magnitudes were found to be present in all current studies investigating wind turbine noise exposure and adverse health effects. Only articles published in English, German or Scandinavian languages were reviewed. Exposure to wind turbines does seem to increase the risk of annoyance and self-reported sleep disturbance in a dose-response relationship. There appears, though, to be a tolerable level of around LAeq of 35 dB. Of the many other claimed health effects of wind turbine noise exposure reported in the literature, however, no conclusive evidence could be found. Future studies should focus on investigations aimed at objectively demonstrating whether or not measureable health-related outcomes can be proven to fluctuate depending on exposure to wind turbines.

A review of damage detection methods for wind turbine blades

NASA Astrophysics Data System (ADS)

Li, Dongsheng; Ho, Siu-Chun M.; Song, Gangbing; Ren, Liang; Li, Hongnan

2015-03-01

Wind energy is one of the most important renewable energy sources and many countries are predicted to increase wind energy portion of their whole national energy supply to about twenty percent in the next decade. One potential obstacle in the use of wind turbines to harvest wind energy is the maintenance of the wind turbine blades. The blades are a crucial and costly part of a wind turbine and over their service life can suffer from factors such as material degradation and fatigue, which can limit their effectiveness and safety. Thus, the ability to detect damage in wind turbine blades is of great significance for planning maintenance and continued operation of the wind turbine. This paper presents a review of recent research and development in the field of damage detection for wind turbine blades. Specifically, this paper reviews frequently employed sensors including fiber optic and piezoelectric sensors, and four promising damage detection methods, namely, transmittance function, wave propagation, impedance and vibration based methods. As a note towards the future development trend for wind turbine sensing systems, the necessity for wireless sensing and energy harvesting is briefly presented. Finally, existing problems and promising research efforts for online damage detection of turbine blades are discussed.

A study of two subgrid-scale models and their effects on wake breakdown behind a wind turbine in uniform inflow

NASA Astrophysics Data System (ADS)

Martinez, Luis; Meneveau, Charles

2014-11-01

Large Eddy Simulations (LES) of the flow past a single wind turbine with uniform inflow have been performed. A goal of the simulations is to compare two turbulence subgrid-scale models and their effects in predicting the initial breakdown, transition and evolution of the wake behind the turbine. Prior works have often observed negligible sensitivities to subgrid-scale models. The flow is modeled using an in-house LES with pseudo-spectral discretization in horizontal planes and centered finite differencing in the vertical direction. Turbines are represented using the actuator line model. We compare the standard constant-coefficient Smagorinsky subgrid-scale model with the Lagrangian Scale Dependent Dynamic model (LSDM). The LSDM model predicts faster transition to turbulence in the wake, whereas the standard Smagorinsky model predicts significantly delayed transition. The specified Smagorinsky coefficient is larger than the dynamic one on average, increasing diffusion thus delaying transition. A second goal is to compare the resulting near-blade properties such as local aerodynamic forces from the LES with Blade Element Momentum Theory. Results will also be compared with those of the SOWFA package, the wind energy CFD framework from NREL. This work is supported by NSF (IGERT and IIA-1243482) and computations use XSEDE resources, and has benefitted from interactions with Dr. M. Churchfield of NREL.

Impacts | Wind | NREL

Science.gov Websites

in hard hats standing on top of a large wind turbine overlooking several other wind turbines in the Framework Transforms FAST Wind Turbine Modeling Tool NREL Assesses National Design Standards for Offshore Wind Resource NREL Identifies Investments for Wind Turbine Drivetrain Technologies Awards R&D 100

Benefits of Two Turbine Rotor Diameters and Hub Heights in the Same Wind Farm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dykes, Katherine L; Stanley, Andrew P. J.; Ning, Andrew

Significant turbine-wake interactions greatly reduce power output in a wind farm. If different turbine hub heights and rotor diameters are included in the same wind farm, the wake interference in the farm will be reduced, resulting in a lower cost of energy (COE) than a farm with identical turbines. In this paper, we present a method to model wind farm COE in farms with hub heights and rotor diameters that vary across the wind farm. We also demonstrate how to optimize these wind farms to minimize COE. The results show that COE can be greatly reduced in wind farms withmore » non-homogeneous turbines, especially when the turbines are spaced close together. For a unidirectional wind rose, including different turbine design in the wind farm has a similar decrease in COE to spreading the wind turbines farther apart. When the rotor diameter and hub height of the wind turbines in a farm are optimized uniformly, a COE decrease of 4% to 13% (depending on the grid spacing and wind shear exponent) is achieved compared to the baseline. When the rotor diameter and turbine heights are optimized non-uniformly, with two different diameters and heights throughout the farm, there is a COE decrease of 22% to 41% compared to the baseline. For a more spread wind rose with a dominant probability from the west, there is a COE decrease between 3% and 10% for uniformly optimized rotor diameter and height compared to the baseline. With two optimized rotor diameters and heights through the farm, a COE decrease of 3% to 19% is achieved. For a similar wind rose shifted such that the dominant wind direction is from the northwest, a COE decrease between 3% and 10% results from uniformly optimized wind turbines compared to the baseline. A COE decrease of 3% to 17% compared to the baseline occurs with two different turbines are optimized throughout the wind farm.« less

Materials for Wind Turbine Blades: An Overview

PubMed Central

Branner, Kim; Petersen, Helga Nørgaard; Beauson, Justine; McGugan, Malcolm; Sørensen, Bent F.

2017-01-01

A short overview of composite materials for wind turbine applications is presented here. Requirements toward the wind turbine materials, loads, as well as available materials are reviewed. Apart from the traditional composites for wind turbine blades (glass fibers/epoxy matrix composites), natural composites, hybrid and nanoengineered composites are discussed. Manufacturing technologies for wind turbine composites, as well their testing and modelling approaches are reviewed. PMID:29120396

Radar Cross Section (RCS) Simulation for Wind Turbines

DTIC Science & Technology

2013-06-01

SECTION (RCS) SIMULATION FOR WIND TURBINES by Cuong Ton June 2013 Thesis Advisor: David C. Jenn Second Reader: Ric Romero THIS PAGE...TITLE AND SUBTITLE RADAR CROSS SECTION (RCS) SIMULATION FOR WIND TURBINES 5. FUNDING NUMBERS 6. AUTHOR(S) Cuong Ton 7. PERFORMING ORGANIZATION...ABSTRACT (maximum 200 words) Wind - turbine power provides energy-independence and greenhouse-gas reduction benefits, but if wind turbines are built

Adaptive neuro-fuzzy methodology for noise assessment of wind turbine.

PubMed

Shamshirband, Shahaboddin; Petković, Dalibor; Hashim, Roslan; Motamedi, Shervin

2014-01-01

Wind turbine noise is one of the major obstacles for the widespread use of wind energy. Noise tone can greatly increase the annoyance factor and the negative impact on human health. Noise annoyance caused by wind turbines has become an emerging problem in recent years, due to the rapid increase in number of wind turbines, triggered by sustainable energy goals set forward at the national and international level. Up to now, not all aspects of the generation, propagation and perception of wind turbine noise are well understood. For a modern large wind turbine, aerodynamic noise from the blades is generally considered to be the dominant noise source, provided that mechanical noise is adequately eliminated. The sources of aerodynamic noise can be divided into tonal noise, inflow turbulence noise, and airfoil self-noise. Many analytical and experimental acoustical studies performed the wind turbines. Since the wind turbine noise level analyzing by numerical methods or computational fluid dynamics (CFD) could be very challenging and time consuming, soft computing techniques are preferred. To estimate noise level of wind turbine, this paper constructed a process which simulates the wind turbine noise levels in regard to wind speed and sound frequency with adaptive neuro-fuzzy inference system (ANFIS). This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method.

Adaptive Neuro-Fuzzy Methodology for Noise Assessment of Wind Turbine

PubMed Central

Shamshirband, Shahaboddin; Petković, Dalibor; Hashim, Roslan; Motamedi, Shervin

2014-01-01

Wind turbine noise is one of the major obstacles for the widespread use of wind energy. Noise tone can greatly increase the annoyance factor and the negative impact on human health. Noise annoyance caused by wind turbines has become an emerging problem in recent years, due to the rapid increase in number of wind turbines, triggered by sustainable energy goals set forward at the national and international level. Up to now, not all aspects of the generation, propagation and perception of wind turbine noise are well understood. For a modern large wind turbine, aerodynamic noise from the blades is generally considered to be the dominant noise source, provided that mechanical noise is adequately eliminated. The sources of aerodynamic noise can be divided into tonal noise, inflow turbulence noise, and airfoil self-noise. Many analytical and experimental acoustical studies performed the wind turbines. Since the wind turbine noise level analyzing by numerical methods or computational fluid dynamics (CFD) could be very challenging and time consuming, soft computing techniques are preferred. To estimate noise level of wind turbine, this paper constructed a process which simulates the wind turbine noise levels in regard to wind speed and sound frequency with adaptive neuro-fuzzy inference system (ANFIS). This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method. PMID:25075621

Lidar-Enhanced Wind Turbine Control: Past, Present, and Future

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scholbrock, Andrew; Fleming, Paul; Schlipf, David

The main challenges in harvesting energy from the wind arise from the unknown incoming turbulent wind field. Balancing the competing interests of reduction in structural loads and increasing energy production is the goal of a wind turbine controller to reduce the cost of producing wind energy. Conventional wind turbines use feedback methods to optimize these goals, reacting to wind disturbances after they have already impacted the wind turbine. Lidar sensors offer a means to provide additional inputs to a wind turbine controller, enabling new techniques to improve control methods, allowing a controller to actuate a wind turbine in anticipation ofmore » an incoming wind disturbance. This paper will look at the development of lidar-enhanced controls and how they have been used for various turbine load reductions with pitch actuation, as well as increased energy production with improved yaw control. Ongoing work will also be discussed to show that combining pitch and torque control using feedforward nonlinear model predictive control can lead to both reduced loads and increased energy production. Future work is also proposed on extending individual wind turbine controls to the wind plant level and determining how lidars can be used for control methods to further lower the cost of wind energy by minimizing wake impacts in a wind farm.« less

NREL to Lead Novel Field Demonstration of Wind Turbine Control at the Wind

Science.gov Websites

Power Plant Level | News | NREL to Lead Novel Field Demonstration of Wind Turbine Control at the Wind Power Plant Level NREL to Lead Novel Field Demonstration of Wind Turbine Control at the Wind to test wind turbine technology controls at the overall wind power plant level. This is a significant

Large, horizontal-axis wind turbines

NASA Technical Reports Server (NTRS)

Linscott, B. S.; Perkins, P.; Dennett, J. T.

1984-01-01

Development of the technology for safe, reliable, environmentally acceptable large wind turbines that have the potential to generate a significant amount of electricity at costs competitive with conventional electric generating systems are presented. In addition, these large wind turbines must be fully compatible with electric utility operations and interface requirements. There are several ongoing large wind system development projects and applied research efforts directed toward meeting the technology requirements for utility applications. Detailed information on these projects is provided. The Mod-O research facility and current applied research effort in aerodynamics, structural dynamics and aeroelasticity, composite and hybrid composite materials, and multiple system interaction are described. A chronology of component research and technology development for large, horizontal axis wind turbines is presented. Wind characteristics, wind turbine economics, and the impact of wind turbines on the environment are reported. The need for continued wind turbine research and technology development is explored. Over 40 references are sited and a bibliography is included.

Wind Energy Conference, Boulder, Colo., April 9-11, 1980, Technical Papers

NASA Astrophysics Data System (ADS)

1980-03-01

Papers are presented concerning the technology, and economics of wind energy conversion systems. Specific topics include the aerodynamic analysis of the Darrieus rotor, the numerical calculation of the flow near horizontal-axis wind turbine rotors, the calculation of dynamic wind turbine rotor loads, markets for wind energy systems, an oscillating-wing windmill, wind tunnel tests of wind rotors, wind turbine generator wakes, the application of a multi-speed electrical generator to wind turbines, the feasibility of wind-powered systems for dairy farms, and wind characteristics over uniform and complex terrain. Attention is also given to performance tests of the DOE/NASA MOD-1 2000-kW wind turbine generator, the assessment of utility-related test data, offshore wind energy conversion systems, and the optimization of wind energy utilization economics through load management.

78 FR 2423 - Draft Environmental Impact Statement (DEIS) for the Proposed Shu'luuk Wind Project on the Campo...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-11

... turbines installed by Invenergy. The manufacturer and model of the wind turbines have not yet been selected... to 85 3-MW wind turbines. Each turbine would have a hub height up to 309 feet, rotor diameter up to... to 80 2-MW wind turbines (totaling 160 MW from wind) in combination with up to 40 1-MW solar...

NREL Leads Wind Farm Modeling Research - Continuum Magazine | NREL

Science.gov Websites

ten 2-MW Bonus wind turbines. Photo provided by HC Sorensen, Middelgrunden Wind Turbine Cooperative ) has created complex computer modeling tools to improve wind turbine design and overall wind farm activity surrounding a multi-megawatt wind turbine. In addition to its work with Doppler LIDAR, the

75 FR 16827 - Notice of Availability of the Draft Granite Mountain Wind, LLC Wind Energy Generation Project...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-02

... wind turbine tower, a maintenance road, and underground electrical and communication lines. Two... to twenty-eight 2.3-megawatt (MW) Siemens wind turbines (or a similar model of wind turbine with a 2... up to 428 feet above the ground. Twenty of the wind turbines would be located on Federal lands...

Using Reconstructed POD Modes as Turbulent Inflow for LES Wind Turbine Simulations

NASA Astrophysics Data System (ADS)

Nielson, Jordan; Bhaganagar, Kiran; Juttijudata, Vejapong; Sirisup, Sirod

2016-11-01

Currently, in order to get realistic atmospheric effects of turbulence, wind turbine LES simulations require computationally expensive precursor simulations. At times, the precursor simulation is more computationally expensive than the wind turbine simulation. The precursor simulations are important because they capture turbulence in the atmosphere and as stated above, turbulence impacts the power production estimation. On the other hand, POD analysis has been shown to be capable of capturing turbulent structures. The current study was performed to determine the plausibility of using lower dimension models from POD analysis of LES simulations as turbulent inflow to wind turbine LES simulations. The study will aid the wind energy community by lowering the computational cost of full scale wind turbine LES simulations, while maintaining a high level of turbulent information and being able to quickly apply the turbulent inflow to multi turbine wind farms. This will be done by comparing a pure LES precursor wind turbine simulation with simulations that use reduced POD mod inflow conditions. The study shows the feasibility of using lower dimension models as turbulent inflow of LES wind turbine simulations. Overall the power production estimation and velocity field of the wind turbine wake are well captured with small errors.

Wind Turbine Structural Dynamics

NASA Technical Reports Server (NTRS)

Miller, D. R. (Editor)

1978-01-01

A workshop on wind turbine structural dynamics was held to review and document current United States work on the dynamic behavior of large wind turbines, primarily of the horizontal-axis type, and to identify and discuss other wind turbine configurations that may have lower cost and weight. Information was exchanged on the following topics: (1) Methods for calculating dynamic loads; (2) Aeroelasticity stability (3) Wind loads, both steady and transient; (4) Critical design conditions; (5) Drive train dynamics; and (6) Behavior of operating wind turbines.

Wind flow characteristics in the wakes of large wind turbines. Volume 1: Analytical model development

NASA Technical Reports Server (NTRS)

Eberle, W. R.

1981-01-01

A computer program to calculate the wake downwind of a wind turbine was developed. Turbine wake characteristics are useful for determining optimum arrays for wind turbine farms. The analytical model is based on the characteristics of a turbulent coflowing jet with modification for the effects of atmospheric turbulence. The program calculates overall wake characteristics, wind profiles, and power recovery for a wind turbine directly in the wake of another turbine, as functions of distance downwind of the turbine. The calculation procedure is described in detail, and sample results are presented to illustrate the general behavior of the wake and the effects of principal input parameters.

Large experimental wind turbines: Where we are now

NASA Technical Reports Server (NTRS)

Thomas, R. L.

1976-01-01

Several large wind turbine projects have been initiated by NASA-Lewis as part of the ERDA wind energy program. The projects consist of progressively large wind turbine ranging from 100 kW with a rotor diameter of 125 feet to 1500 kW with rotor diameters of 200 to 300 feet. Also included is supporting research and technology for large wind turbines and for lowering the costs and increasing the reliability of the major wind turbine components. The results and status of the above projects are briefly discussed in this report. In addition, a brief summary and status of the plans for selecting the utility sites for the experimental wind turbines is also discussed.

Methods and apparatus for rotor load control in wind turbines

DOEpatents

Moroz, Emilian Mieczyslaw

2006-08-22

A wind turbine having a rotor, at least one rotor blade, and a plurality of generators, of which a first generator is configured to provide power to an electric grid and a second generator is configured to provide power to the wind turbine during times of grid loss. The wind turbine is configured to utilize power provided by the second generator to reduce loads on the wind turbine during times of grid loss.

Simulations of an Offshore Wind Farm Using Large-Eddy Simulation and a Torque-Controlled Actuator Disc Model

NASA Astrophysics Data System (ADS)

Creech, Angus; Früh, Wolf-Gerrit; Maguire, A. Eoghan

2015-05-01

We present here a computational fluid dynamics (CFD) simulation of Lillgrund offshore wind farm, which is located in the Øresund Strait between Sweden and Denmark. The simulation combines a dynamic representation of wind turbines embedded within a large-eddy simulation CFD solver and uses hr-adaptive meshing to increase or decrease mesh resolution where required. This allows the resolution of both large-scale flow structures around the wind farm, and the local flow conditions at individual turbines; consequently, the response of each turbine to local conditions can be modelled, as well as the resulting evolution of the turbine wakes. This paper provides a detailed description of the turbine model which simulates the interaction between the wind, the turbine rotors, and the turbine generators by calculating the forces on the rotor, the body forces on the air, and instantaneous power output. This model was used to investigate a selection of key wind speeds and directions, investigating cases where a row of turbines would be fully aligned with the wind or at specific angles to the wind. Results shown here include presentations of the spin-up of turbines, the observation of eddies moving through the turbine array, meandering turbine wakes, and an extensive wind farm wake several kilometres in length. The key measurement available for cross-validation with operational wind farm data is the power output from the individual turbines, where the effect of unsteady turbine wakes on the performance of downstream turbines was a main point of interest. The results from the simulations were compared to the performance measurements from the real wind farm to provide a firm quantitative validation of this methodology. Having achieved good agreement between the model results and actual wind farm measurements, the potential of the methodology to provide a tool for further investigations of engineering and atmospheric science problems is outlined.

Publications | Wind | NREL

Science.gov Websites

-specific analysis can be used to assess the risk induced by loss of a wind turbine blade. The study used for different wind turbine configurations. The authors used assumptions specific to the National Wind ., failure rate for wind turbine rotors) are based on a 13-year-old report on wind turbines installed in

Markovian properties of wind turbine wakes within a 3x3 array

NASA Astrophysics Data System (ADS)

Melius, Matthew; Tutkun, Murat; Cal, Raúl Bayoán

2012-11-01

Wind turbine arrays have proven to be significant sources of renewable energy. Accurate projections of energy production is difficult to achieve because the wake of a wind turbine is highly intermittent and turbulent. Seeking to further the understanding of the downstream propagation of wind turbine wakes, a stochastic analysis of experimentally obtained turbulent flow data behind a wind turbine was performed. A 3x3 wind turbine array was constructed in the test section of a recirculating wind tunnel where X-wire anemometers were used to collect point velocity statistics. In this work, mathematics of the theory of Markovian processes are applied to obtain a statistical description of longitudinal velocity increments inside the turbine wake using conditional probability density functions. Our results indicate an existence of Markovian properties at scales on the order of the Taylor microscale, λ, which has also been observed and documented in different turbulent flows. This leads to characterization of the multi-point description of the wind turbine wakes using the most recent states of the flow.

Offshore Wind Research | Wind | NREL

Science.gov Websites

validation and certification. A photo of an offshore wind turbine with a yellow foundation floating in the wind turbine with three turbines and blue ocean in the background. Design Methods, Tools, and Standards Applying 35 years of wind turbine validation expertise, NREL has developed instrumentation for high

Preliminary results of the large experimental wind turbine phase of the national wind energy program

NASA Technical Reports Server (NTRS)

Thomas, R. L.; Sholes, T.; Sholes, J. E.

1975-01-01

The preliminary results of two projects in the development phase of reliable wind turbines designed to supply cost-competitive electrical energy were discussed. An experimental 100 kW wind turbine design and its status are first reviewed. The results of two parallel design studies for determining the configurations and power levels for wind turbines with minimum energy costs are also discussed. These studies predict wind energy costs of 1.5 to 7 cents per kW-h for wind turbines produced in quantities of 100 to 1000 per year and located at sites having average winds of 12 to 18 mph.

Physical Model Study of the Fully Developed Wind Turbine Array Boundary Layer in the UNH Flow Physics Facility

NASA Astrophysics Data System (ADS)

Turner, John; Wosnik, Martin

2015-11-01

Results from an experimental study of an array of up to 100 model wind turbines with 0.25 m diameter are reported. The study was conducted in the UNH Flow Physics Facility (FPF), which has test section dimensions of 6.0 m wide, 2.7 m high and 72.0 m long. For a given configuration (spacing, initial conditions, etc.), the model wind farm reaches a ``fully developed'' condition, in which turbulence statistics remain the same from one row to the next within and above the wind turbine array. Of interest is the transport of kinetic energy within the wind turbine array boundary layer (WTABL). Model wind farms of up to 20 rows are possible in the FPF at the wind turbine scale used. The present studies in the FPF are able to achieve the fully developed WTABL condition, which can provide valuable insight to the optimization of wind farm energy production. The FPF can achieve a boundary layer height on the order of 1 m at the beginning of the wind turbine array. The wind turbine array was constructed of porous disks, which where drag (thrust) matched to wind turbines at typical operating conditions and therefore act as momentum sinks similar to wind turbines. The flow in the WTABL was measured with constant temperature anemometry using an X-wire.

Preliminary results of the large experimental wind turbine phase of the national wind energy program

NASA Technical Reports Server (NTRS)

Thomas, R. L.; Sholes, J. E.

1975-01-01

A major phase of the wind energy program is the development of reliable wind turbines for supplying cost-competitive electrical energy. This paper discusses the preliminary results of two projects in this phase of the program. First an experimental 100 kW wind turbine design and its status are reviewed. Also discussed are the results of two parallel design studies for determining the configurations and power levels for wind turbines with minimum energy costs. These studies show wind energy costs of 7 to 1.5 c/kWH for wind turbines produced in quantities of 100 to 1000 a year and located at sites having average winds of 12 to 18 mph.

Analysis of the Environmental Impact on Remanufacturing Wind Turbines

NASA Astrophysics Data System (ADS)

Sosa Skrainka, Manuel R.

To deliver clean energy the use of wind turbines is essential. In June 2011 there was an installed wind capacity equivalent to 211,000MW world-wide (WWEA, 2011). By the end of the year 2009 the U.S. had 35,100MW of wind energy installed capacity to generate electricity (AWEA, 2010). This industry has grown in recent years and is expected to grow even more in the future. The environmental impacts that will arise from the increased number of wind turbines and their end-of-life should be addressed, as large amounts of resources will be required to satisfy the current and future market demands for wind turbines. Since future 10MW wind turbines are expected to be as heavy as 1000 tons each, the study of the environmental response of profitable retirement strategies, such as remanufacturing for these machines, must be considered. Because of the increased number of wind turbines and the materials used, this study provides a comparison between the environmental impacts from remanufacturing the components installed inside the nacelle of multi-megawatt wind turbines and wind turbines manufactured using new components. The study methodology is the following: • Describe the life-cycle and the materials and processes employed for the manufacture and remanufacturing for components inside the nacelle. • Identify remanufacturing alternatives for the components inside the nacelle at the end of the expected life-time service of wind turbines. • Evaluate the environmental impacts from the remanufactured components and compare the results with the impacts of the manufacturing of new components using SimaPro. • Conduct sensitivity analysis over the critical parameters of the life cycle assessment • Propose the most environmentally friendly options for the retirement of each major component of wind turbines. After an analysis of the scenarios the goal of the study is to evaluate remanufacturing as an end-of-life option from an environmental perspective for commercial multi-megawatt wind turbines targeted for secondary wind turbine markets.

Effects of incoming surface wind conditions on the wake characteristics and dynamic wind loads acting on a wind turbine model

NASA Astrophysics Data System (ADS)

Tian, Wei; Ozbay, Ahmet; Hu, Hui

2014-12-01

An experimental investigation was conducted to examine the effects of incoming surface wind conditions on the wake characteristics and dynamic wind loads acting on a wind turbine model. The experimental study was performed in a large-scale wind tunnel with a scaled three-blade Horizontal Axial Wind Turbine model placed in two different types of Atmospheric Boundary Layer (ABL) winds with distinct mean and turbulence characteristics. In addition to measuring dynamic wind loads acting on the model turbine by using a force-moment sensor, a high-resolution Particle Image Velocimetry system was used to achieve detailed flow field measurements to characterize the turbulent wake flows behind the model turbine. The measurement results reveal clearly that the discrepancies in the incoming surface winds would affect the wake characteristics and dynamic wind loads acting on the model turbine dramatically. The dynamic wind loads acting on the model turbine were found to fluctuate much more significantly, thereby, much larger fatigue loads, for the case with the wind turbine model sited in the incoming ABL wind with higher turbulence intensity levels. The turbulent kinetic energy and Reynolds stress levels in the wake behind the model turbine were also found to be significantly higher for the high turbulence inflow case, in comparison to those of the low turbulence inflow case. The flow characteristics in the turbine wake were found to be dominated by the formation, shedding, and breakdown of various unsteady wake vortices. In comparison with the case with relatively low turbulence intensities in the incoming ABL wind, much more turbulent and randomly shedding, faster dissipation, and earlier breakdown of the wake vortices were observed for the high turbulence inflow case, which would promote the vertical transport of kinetic energy by entraining more high-speed airflow from above to re-charge the wake flow and result in a much faster recovery of the velocity deficits in the turbine wake.

A wind tunnel study on the effects of complex topography on wind turbine performance

NASA Astrophysics Data System (ADS)

Howard, Kevin; Hu, Stephen; Chamorro, Leonardo; Guala, Michele

2012-11-01

A set of wind tunnel experiments were conducted to study the response of a wind turbine under flow conditions typically observed at the wind farm scale, in complex terrain. A scale model wind turbine was placed in a fully developed turbulent boundary layer flow obtained in the SAFL Wind Tunnel. Experiments focused on the performance of a turbine model, under the effects induced by a second upwind turbine or a by three-dimensional, sinusoidal hill, peaking at the turbine hub height. High frequency measurements of fluctuating streamwise and wall normal velocities were obtained with a X-wire anemometer simultaneously with the rotor angular velocity and the turbine(s) voltage output. Velocity measurements in the wake of the first turbine and of the hill were used to determine the inflow conditions for the downwind test turbine. Turbine performance was inferred by the mean and fluctuating voltage statistics. Specific experiments were devoted to relate the mean voltage to the mean hub velocity, and the fluctuating voltage to the unsteadiness in the rotor kinematics induced by the perturbed (hill or turbine) or unperturbed (boundary layer) large scales of the incoming turbulent flow. Results show that the voltage signal can be used to assess turbine performance in complex flows.

Visualization and analysis of vortex-turbine intersections in wind farms.

PubMed

Shafii, Sohail; Obermaier, Herald; Linn, Rodman; Koo, Eunmo; Hlawitschka, Mario; Garth, Christoph; Hamann, Bernd; Joy, Kenneth I

2013-09-01

Characterizing the interplay between the vortices and forces acting on a wind turbine's blades in a qualitative and quantitative way holds the potential for significantly improving large wind turbine design. This paper introduces an integrated pipeline for highly effective wind and force field analysis and visualization. We extract vortices induced by a turbine's rotation in a wind field, and characterize vortices in conjunction with numerically simulated forces on the blade surfaces as these vortices strike another turbine's blades downstream. The scientifically relevant issue to be studied is the relationship between the extracted, approximate locations on the blades where vortices strike the blades and the forces that exist in those locations. This integrated approach is used to detect and analyze turbulent flow that causes local impact on the wind turbine blade structure. The results that we present are based on analyzing the wind and force field data sets generated by numerical simulations, and allow domain scientists to relate vortex-blade interactions with power output loss in turbines and turbine life expectancy. Our methods have the potential to improve turbine design to save costs related to turbine operation and maintenance.

Aerodynamic study of a stall regulated horizontal-axis wind turbine

NASA Astrophysics Data System (ADS)

Constantinescu, S. G.; Crunteanu, D. E.; Niculescu, M. L.

2013-10-01

The wind energy is deemed as one of the most durable energetic variants of the future because the wind resources are immense. Furthermore, one predicts that the small wind turbines will play a vital role in the urban environment. Unfortunately, the complexity and the price of pitch regulated small horizontal-axis wind turbines represent ones of the main obstacles to widespread the use in populated zones. Moreover, the energetic efficiency of small stall regulated wind turbines has to be high even at low and medium wind velocities because, usually the cities are not windy places. During the running stall regulated wind turbines, due to the extremely broad range of the wind velocity, the angle of attack can reach high values and some regions of the blade will show stall and post-stall behavior. This paper deals with stall and post-stall regimes because they can induce significant vibrations, fatigue and even the wind turbine failure.

System Identification for the Clipper Liberty C96 Wind Turbine

NASA Astrophysics Data System (ADS)

Showers, Daniel

System identification techniques are powerful tools that help improve modeling capabilities of real world dynamic systems. These techniques are well established and have been successfully used on countless systems in many areas. However, wind turbines provide a unique challenge for system identification because of the difficulty in measuring its primary input: wind. This thesis first motivates the problem by demonstrating the challenges with wind turbine system identification using both simulations and real data. It then suggests techniques toward successfully identifying a dynamic wind turbine model including the notion of an effective wind speed and how it might be measured. Various levels of simulation complexity are explored for insights into calculating an effective wind speed. In addition, measurements taken from the University of Minnesota's Clipper Liberty C96 research wind turbine are used for a preliminary investigation into the effective wind speed calculation and system identification of a real world wind turbine.

Field investigation of a wake structure downwind of a VANT (Vertical-Axis Wind Turbine) in a wind farm array

NASA Astrophysics Data System (ADS)

Liu, H. T.; Buck, J. W.; Germain, A. C.; Hinchee, M. E.; Solt, T. S.; Leroy, G. M.; Srnsky, R. A.

1988-09-01

The effects of upwind turbine wakes on the performance of a FloWind 17-m vertical-axis wind turbine (VAWT) were investigated through a series of field experiments conducted at the FloWind wind farm on Cameron Ridge, Tehachapi, California. From the field measurements, we derived the velocity and power/energy deficits under various turbine on/off configurations. Much information was provided to characterize the structure of VAWT wakes and to assess their effects on the performance of downwind turbines. A method to estimate the energy deficit was developed based on the measured power deficit and the wind speed distributions. This method may be adopted for other turbine types and sites. Recommendations are made for optimizing wind farm design and operations, as well as for wind energy management.

Numerical simulations with a FSI-calibrated actuator disk model of wind turbines operating in stratified ABLs

NASA Astrophysics Data System (ADS)

Gohari, S. M. Iman; Sarkar, Sutanu; Korobenko, Artem; Bazilevs, Yuri

2017-11-01

Numerical simulations of wind turbines operating under different regimes of stability are performed using LES. A reduced model, based on the generalized actuator disk model (ADM), is implemented to represent the wind turbines within the ABL. Data from the fluid-solid interaction (FSI) simulations of wind turbines have been used to calibrate and validate the reduced model. The computational cost of this method to include wind turbines is affordable and incurs an overhead as low as 1.45%. Using this reduced model, we study the coupling of unsteady turbulent flow with the wind turbine under different ABL conditions: (i) A neutral ABL with zero heat-flux and inversion layer at 350m, in which the incoming wind has the maximum mean shear between the heights of upper-tip and lower-tip; (2) A shallow ABL with surface cooling rate of -1 K/hr wherein the low level jet occurs at the wind turbine hub height. We will discuss how the differences in the unsteady flow between the two ABL regimes impact the wind turbine performance.

Aerodynamic design and analysis of small horizontal axis wind turbine blades

NASA Astrophysics Data System (ADS)

Tang, Xinzi

This work investigates the aerodynamic design and analysis of small horizontal axis wind turbine blades via the blade element momentum (BEM) based approach and the computational fluid dynamics (CFD) based approach. From this research, it is possible to draw a series of detailed guidelines on small wind turbine blade design and analysis. The research also provides a platform for further comprehensive study using these two approaches. The wake induction corrections and stall corrections of the BEM method were examined through a case study of the NREL/NASA Phase VI wind turbine. A hybrid stall correction model was proposed to analyse wind turbine power performance. The proposed model shows improvement in power prediction for the validation case, compared with the existing stall correction models. The effects of the key rotor parameters of a small wind turbine as well as the blade chord and twist angle distributions on power performance were investigated through two typical wind turbines, i.e. a fixed-pitch variable-speed (FPVS) wind turbine and a fixed-pitch fixed-speed (FPFS) wind turbine. An engineering blade design and analysis code was developed in MATLAB to accommodate aerodynamic design and analysis of the blades.. The linearisation for radial profiles of blade chord and twist angle for the FPFS wind turbine blade design was discussed. Results show that, the proposed linearisation approach leads to reduced manufacturing cost and higher annual energy production (AEP), with minimal effects on the low wind speed performance. Comparative studies of mesh and turbulence models in 2D and 3D CFD modelling were conducted. The CFD predicted lift and drag coefficients of the airfoil S809 were compared with wind tunnel test data and the 3D CFD modelling method of the NREL/NASA Phase VI wind turbine were validated against measurements. Airfoil aerodynamic characterisation and wind turbine power performance as well as 3D flow details were studied. The detailed flow characteristics from the CFD modelling are quantitatively comparable to the measurements, such as blade surface pressure distribution and integrated forces and moments. It is confirmed that the CFD approach is able to provide a more detailed qualitative and quantitative analysis for wind turbine airfoils and rotors..

Smart structure for small wind turbine blade

NASA Astrophysics Data System (ADS)

Supeni, E. E.; Epaarachchi, J. A.; Islam, M. M.; Lau, K. T.

2013-08-01

Wind energy is seen as a viable alternative energy option for future energy demand. The blades of wind turbines are generally regarded as the most critical component of the wind turbine system. Ultimately, the blades act as the prime mover of the whole system which interacts with the wind flow during the production of energy. During wind turbine operation the wind loading cause the deflection of the wind turbine blade which can be significant and affect the turbine efficiency. Such a deflection in wind blade not only will result in lower performance in electrical power generation but also increase of material degradation due high fatigue life and can significantly shorten the longevity for the wind turbine material. In harnessing stiffness of the blade will contribute massive weight factor and consequently excessive bending moment. To overcome this excessive deflection due to wind loading on the blade, it is feasible to use shape memory alloy (SMA) wires which has ability take the blade back to its optimal operational shape. This paper details analytical and experimental work being carried out to minimize blade flapping deflection using SMA.

University of Washington/ Northwest National Marine Renewable Energy Center Tidal Current Technology Test Protocol, Instrumentation, Design Code, and Oceanographic Modeling Collaboration: Cooperative Research and Development Final Report, CRADA Number CRD-11-452

DOE Office of Scientific and Technical Information (OSTI.GOV)

Driscoll, Frederick R.

The University of Washington (UW) - Northwest National Marine Renewable Energy Center (UW-NNMREC) and the National Renewable Energy Laboratory (NREL) will collaborate to advance research and development (R&D) of Marine Hydrokinetic (MHK) renewable energy technology, specifically renewable energy captured from ocean tidal currents. UW-NNMREC is endeavoring to establish infrastructure, capabilities and tools to support in-water testing of marine energy technology. NREL is leveraging its experience and capabilities in field testing of wind systems to develop protocols and instrumentation to advance field testing of MHK systems. Under this work, UW-NNMREC and NREL will work together to develop a common instrumentation systemmore » and testing methodologies, standards and protocols. UW-NNMREC is also establishing simulation capabilities for MHK turbine and turbine arrays. NREL has extensive experience in wind turbine array modeling and is developing several computer based numerical simulation capabilities for MHK systems. Under this CRADA, UW-NNMREC and NREL will work together to augment single device and array modeling codes. As part of this effort UW NNMREC will also work with NREL to run simulations on NREL's high performance computer system.« less

Common Risk Criteria Standards for National Test Ranges

DTIC Science & Technology

2017-09-01

critical assets. Equipment and facilities that comprise part of an on- or off-base renewable energy system, such as wind turbine generation facilities...to be protected. As an example, for a wind turbine farm, the unit component would be a single wind turbine . A unit component can be considered...functionality of the larger system to which the unit component belongs. For example, a single wind turbine is a unit component of a wind turbine farm. A

Measuring wind turbine wakes and unsteady loading in a micro wind farm model

NASA Astrophysics Data System (ADS)

Bossuyt, Juliaan; Meneveau, Charles; Meyers, Johan

2014-11-01

Very large wind farms, approximating the ``infinite'' asymptotic limit, are often studied with LES using periodic boundary conditions. In order to create an experimental realization of such large wind-turbine arrays in a wind tunnel experiment including over 100 turbines, a very small-scale turbine model based on a 3 cm diameter porous disk is designed. The porous disc matches a realistic thrust coefficient between 0.75--0.85, and the far wake flow characteristics of a rotating wind turbine. As a first step, we characterize the properties of a single model turbine. Hot-wire measurements are performed for uniform inflow conditions with different background turbulence intensity levels. Strain gage measurements are used to measure the mean value and power spectra of the thrust force, power output and wind velocity in front of the turbine. The dynamics of the wind turbine are modeled making it possible to measure force spectra at least up to the natural frequency of the model. This is shown by reproducing the -5/3 spectrum from the incoming flow and the vortex shedding signatures of an upstream obstruction. An array with a large number of these instrumented model turbines is placed in JHU's Corrsin wind tunnel, to study effects of farm layout on total power output and turbine loading. Work supported by ERC (ActiveWindFarms, Grant No: 306471), and by NSF (CBET-113380 and IIA-1243482).

Wind Turbine Wakes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelley, Christopher Lee; Maniaci, David Charles; Resor, Brian R.

2015-10-01

The total energy produced by a wind farm depends on the complex interaction of many wind turbines operating in proximity with the turbulent atmosphere. Sometimes, the unsteady forces associated with wind negatively influence power production, causing damage and increasing the cost of producing energy associated with wind power. Wakes and the motion of air generated by rotating blades need to be better understood. Predicting wakes and other wind forces could lead to more effective wind turbine designs and farm layouts, thereby reducing the cost of energy, allowing the United States to increase the installed capacity of wind energy. The Windmore » Energy Technologies Department at Sandia has collaborated with the University of Minnesota to simulate the interaction of multiple wind turbines. By combining the validated, large-eddy simulation code with Sandia’s HPC capability, this consortium has improved its ability to predict unsteady forces and the electrical power generated by an array of wind turbines. The array of wind turbines simulated were specifically those at the Sandia Scaled Wind Farm Testbed (SWiFT) site which aided the design of new wind turbine blades being manufactured as part of the National Rotor Testbed project with the Department of Energy.« less

Assessment of C-Type Darrieus Wind Turbine Under Low Wind Speed Condition

NASA Astrophysics Data System (ADS)

Misaran, M. S.; Rahman, Md. M.; Muzammil, W. K.; Ismail, M. A.

2017-07-01

Harvesting wind energy in in a low wind speed region is deem un-economical if not daunting task. Study shows that a minimum cut in speed of 3.5 m/s is required to extract a meaningful wind energy for electricity while a mean speed of 6 m/s is preferred. However, in Malaysia the mean speed is at 2 m/s with certain potential areas having 3 m/s mean speed. Thus, this work aims to develop a wind turbine that able to operate at lower cut-in speed and produce meaningful power for electricity generation. A C-type Darrieus blade is selected as it shows good potential to operate in arbitrary wind speed condition. The wind turbine is designed and fabricated in UMS labs while the performance of the wind turbine is evaluated in a simulated wind condition. Test result shows that the wind turbine started to rotate at 1 m/s compared to a NACA 0012 Darrieus turbine that started to rotate at 3 m/s. The performance of the turbine shows that it have good potential to be used in an intermittent arbitrary wind speed condition as well as low mean wind speed condition.

Study on the abnormal data rejection and normal condition evaluation applied in wind turbine farm

NASA Astrophysics Data System (ADS)

Zhang, Ying; Qian, Zheng; Tian, Shuangshu

2016-01-01

The condition detection of wind turbine is always an important issue which attract more and more attentions because of the rapid development of wind farm. And the on-line data analysis is also difficult since a lot of measured data is collected. In this paper, the abnormal data rejection and normal condition evaluation of wind turbine is processed. At first, since there are large amounts of abnormal data in the normal operation of wind turbine, which is probably caused by fault, maintenance downtime, power-limited operation and failure of wind speed sensor, a novel method is proposed to reject abnormal data in order to make more accurate analysis for the wind turbine condition. The core principle of this method is to fit the wind power curves by using the scatter diagram. The data outside the area covered by wind power curves is the abnormal data. The calculation shows that the abnormal data is rejected effectively. After the rejection, the vibration signals of wind turbine bearing which is a critical component are analyzed and the relationship between the vibration characteristic value and the operating condition of wind turbine is discussed. It will provide powerful support for the accurate fault analysis of wind turbine.

Towers for Offshore Wind Turbines

NASA Astrophysics Data System (ADS)

Kurian, V. J.; Narayanan, S. P.; Ganapathy, C.

2010-06-01

Increasing energy demand coupled with pollution free production of energy has found a viable solution in wind energy. Land based windmills have been utilized for power generation for more than two thousand years. In modern times wind generated power has become popular in many countries. Offshore wind turbines are being used in a number of countries to tap the energy from wind over the oceans and convert to electric energy. The advantages of offshore wind turbines as compared to land are that offshore winds flow at higher speed than onshore winds and the more available space. In some land based settings, for better efficiency, turbines are separated as much as 10 rotor diameters from each other. In offshore applications where only two wind directions are likely to predominate, the distances between the turbines arranged in a line can be shortened to as little as two or four rotor diameters. Today, more than a dozen offshore European wind facilities with turbine ratings of 450 kw to 3.6 MW exist offshore in very shallow waters of 5 to 12 m. Compared to onshore wind turbines, offshore wind turbines are bigger and the tower height in offshore are in the range of 60 to 80 m. The water depths in oceans where offshore turbines can be located are within 30 m. However as the distance from land increases, the costs of building and maintaining the turbines and transmitting the power back to shore also increase sharply. The objective of this paper is to review the parameters of design for the maximum efficiency of offshore wind turbines and to develop types offshore towers to support the wind turbines. The methodology of design of offshore towers to support the wind turbine would be given and the environmental loads for the design of the towers would be calculated for specific cases. The marine corrosion on the towers and the methods to control the corrosion also would be briefly presented. As the wind speeds tend to increase with distance from the shore, turbines build father offshore will be able to capture more wind energy. Currently two types of towers are considered. Cylindrical tubular structures and truss type structures. But truss type structures have less weight and flexibility in design. The construction of the offshore towers to harness the wind energy is also presented. The results will include the calculation of wind and wave forces on the tower and the design details for the tower.

Investigation of Wind Turbine Rotor Concepts for Offshore Wind Farms

NASA Astrophysics Data System (ADS)

Ceyhan, Özlem; Grasso, Francesco

2014-06-01

Current plans in offshore wind energy developments call for further reduction of cost of energy. In order to contribute to this goal, several wind turbine rotor concepts have been investigated. Assuming the future offshore wind turbines will operate only in the offshore wind farms, the rotor concepts are not only evaluated for their stand-alone performances and their potential in reducing the loads, but also for their performance in an offshore wind farm. In order to do that, the 10MW reference wind turbine designed in Innwind.EU project is chosen as baseline. Several rotor parameters have been modified and their influences are investigated for offshore wind turbine design purposes. This investigation is carried out as a conceptual parametrical study. All concepts are evaluated numerically with BOT (Blade optimisation tool) software in wind turbine level and with Farmflow software in wind farm level for two wind farm layouts. At the end, all these concepts are compared with each other in terms of their advantages and disadvantages.

Habitat use of bats in relation to wind turbines revealed by GPS tracking

PubMed Central

Roeleke, Manuel; Blohm, Torsten; Kramer-Schadt, Stephanie; Yovel, Yossi; Voigt, Christian C.

2016-01-01

Worldwide, many countries aim at countering global climate change by promoting renewable energy. Yet, recent studies highlight that so-called green energy, such as wind energy, may come at environmental costs, for example when wind turbines kill birds and bats. Using miniaturized GPS loggers, we studied how an open-space foraging bat with high collision risk with wind turbines, the common noctule Nyctalus noctula (Schreber, 1774), interacts with wind turbines. We compared actual flight trajectories to correlated random walks to identify habitat variables explaining the movements of bats. Both sexes preferred wetlands but used conventionally managed cropland less than expected based on availability. During midsummer, females traversed the land on relatively long flight paths and repeatedly came close to wind turbines. Their flight heights above ground suggested a high risk of colliding with wind turbines. In contrast, males recorded in early summer commuted straight between roosts and foraging areas and overall flew lower than the operating range of most turbine blades, suggesting a lower collision risk. Flight heights of bats suggest that during summer the risk of collision with wind turbines was high for most studied bats at the majority of currently installed wind turbines. For siting of wind parks, preferred bat habitats and commuting routes should be identified and avoided. PMID:27373219

Design and development of nautilus whorl-wind turbine

NASA Astrophysics Data System (ADS)

R, Pramod; Kumar, G. B. Veeresh; Harsha, P. Sai Sri; Kumar, K. A. Udaya

2017-07-01

Our life is directly related to energy and its consumption, and the issues of energy research are extremely important and highly sensitive. Scientists and researchers attempt to accelerate solutions for wind energy generation, design parameters under the influence of novel policies adopted for energy management and the concerns for global warming and climate change. The objective of this study is to design a small wind turbine that is optimized for the constraints that come with residential use. The study is aimed at designing a wind turbine for tapping the low speed wind in urban locations. The design process includes the selection of the wind turbine type and the determination of the blade airfoil, finding the maximum drag model and manufacturing of the turbine economically. In this study, the Nautilus turbine is modeled, simulated and the characteristic curves are plotted. The cutting in wind speed for the turbine is around 1m/s. The turbine rotates in a range of 20 rpm to 500 rpm at wind speeds 1m/s to 10m/s On a below average day at noon where the wind speed are usually low the turbine recorded an rpm of 120 (average value) at 4m/s wind speeds. This study focuses on a computational fluid dynamics analysis of compressible radially outward flow.

Habitat use of bats in relation to wind turbines revealed by GPS tracking

NASA Astrophysics Data System (ADS)

Roeleke, Manuel; Blohm, Torsten; Kramer-Schadt, Stephanie; Yovel, Yossi; Voigt, Christian C.

2016-07-01

Worldwide, many countries aim at countering global climate change by promoting renewable energy. Yet, recent studies highlight that so-called green energy, such as wind energy, may come at environmental costs, for example when wind turbines kill birds and bats. Using miniaturized GPS loggers, we studied how an open-space foraging bat with high collision risk with wind turbines, the common noctule Nyctalus noctula (Schreber, 1774), interacts with wind turbines. We compared actual flight trajectories to correlated random walks to identify habitat variables explaining the movements of bats. Both sexes preferred wetlands but used conventionally managed cropland less than expected based on availability. During midsummer, females traversed the land on relatively long flight paths and repeatedly came close to wind turbines. Their flight heights above ground suggested a high risk of colliding with wind turbines. In contrast, males recorded in early summer commuted straight between roosts and foraging areas and overall flew lower than the operating range of most turbine blades, suggesting a lower collision risk. Flight heights of bats suggest that during summer the risk of collision with wind turbines was high for most studied bats at the majority of currently installed wind turbines. For siting of wind parks, preferred bat habitats and commuting routes should be identified and avoided.

Habitat use of bats in relation to wind turbines revealed by GPS tracking.

PubMed

Roeleke, Manuel; Blohm, Torsten; Kramer-Schadt, Stephanie; Yovel, Yossi; Voigt, Christian C

2016-07-04

Worldwide, many countries aim at countering global climate change by promoting renewable energy. Yet, recent studies highlight that so-called green energy, such as wind energy, may come at environmental costs, for example when wind turbines kill birds and bats. Using miniaturized GPS loggers, we studied how an open-space foraging bat with high collision risk with wind turbines, the common noctule Nyctalus noctula (Schreber, 1774), interacts with wind turbines. We compared actual flight trajectories to correlated random walks to identify habitat variables explaining the movements of bats. Both sexes preferred wetlands but used conventionally managed cropland less than expected based on availability. During midsummer, females traversed the land on relatively long flight paths and repeatedly came close to wind turbines. Their flight heights above ground suggested a high risk of colliding with wind turbines. In contrast, males recorded in early summer commuted straight between roosts and foraging areas and overall flew lower than the operating range of most turbine blades, suggesting a lower collision risk. Flight heights of bats suggest that during summer the risk of collision with wind turbines was high for most studied bats at the majority of currently installed wind turbines. For siting of wind parks, preferred bat habitats and commuting routes should be identified and avoided.

Onshore industrial wind turbine locations for the United States

USGS Publications Warehouse

Diffendorfer, Jay E.; Compton, Roger; Kramer, Louisa; Ancona, Zach; Norton, Donna

2017-01-01

This dataset provides industrial-scale onshore wind turbine locations in the United States, corresponding facility information, and turbine technical specifications. The database has wind turbine records that have been collected, digitized, locationally verified, and internally quality controlled. Turbines from the Federal Aviation Administration Digital Obstacles File, through product release date July 22, 2013, were used as the primary source of turbine data points. The dataset was subsequently revised and reposted as described in the revision histories for the report. Verification of the turbine positions was done by visual interpretation using high-resolution aerial imagery in Environmental Systems Research Institute (Esri) ArcGIS Desktop. Turbines without Federal Aviation Administration Obstacles Repository System numbers were visually identified and point locations were added to the collection. We estimated a locational error of plus or minus 10 meters for turbine locations. Wind farm facility names were identified from publicly available facility datasets. Facility names were then used in a Web search of additional industry publications and press releases to attribute additional turbine information (such as manufacturer, model, and technical specifications of wind turbines). Wind farm facility location data from various wind and energy industry sources were used to search for and digitize turbines not in existing databases. Technical specifications for turbines were assigned based on the wind turbine make and model as described in literature, specifications listed in the Federal Aviation Administration Digital Obstacles File, and information on the turbine manufacturer’s Web site. Some facility and turbine information on make and model did not exist or was difficult to obtain. Thus, uncertainty may exist for certain turbine specifications. That uncertainty was rated and a confidence was recorded for both location and attribution data quality.

Annoyance, detection and recognition of wind turbine noise.

PubMed

Van Renterghem, Timothy; Bockstael, Annelies; De Weirt, Valentine; Botteldooren, Dick

2013-07-01

Annoyance, recognition and detection of noise from a single wind turbine were studied by means of a two-stage listening experiment with 50 participants with normal hearing abilities. In-situ recordings made at close distance from a 1.8-MW wind turbine operating at 22 rpm were mixed with road traffic noise, and processed to simulate indoor sound pressure levels at LAeq 40 dBA. In a first part, where people were unaware of the true purpose of the experiment, samples were played during a quiet leisure activity. Under these conditions, pure wind turbine noise gave very similar annoyance ratings as unmixed highway noise at the same equivalent level, while annoyance by local road traffic noise was significantly higher. In a second experiment, listeners were asked to identify the sample containing wind turbine noise in a paired comparison test. The detection limit of wind turbine noise in presence of highway noise was estimated to be as low as a signal-to-noise ratio of -23 dBA. When mixed with local road traffic, such a detection limit could not be determined. These findings support that noticing the sound could be an important aspect of wind turbine noise annoyance at the low equivalent levels typically observed indoors in practice. Participants that easily recognized wind-turbine(-like) sounds could detect wind turbine noise better when submersed in road traffic noise. Recognition of wind turbine sounds is also linked to higher annoyance. Awareness of the source is therefore a relevant aspect of wind turbine noise perception which is consistent with previous research. Copyright © 2013 Elsevier B.V. All rights reserved.

Evaluation of Wind Energy Production in Texas using Geographic Information Systems (GIS)

NASA Astrophysics Data System (ADS)

Ferrer, L. M.

2017-12-01

Texas has the highest installed wind capacity in the United States. The purpose of this research was to estimate the theoretical wind turbine energy production and the utilization ratio of wind turbines in Texas. Windfarm data was combined applying Geographic Information System (GIS) methodology to create an updated GIS wind turbine database, including location and technical specifications. Applying GIS diverse tools, the windfarm data was spatially joined with National Renewable Energy Laboratory (NREL) wind data to calculate the wind speed at each turbine hub. The power output for each turbine at the hub wind speed was evaluated by the GIS system according the respective turbine model power curve. In total over 11,700 turbines are installed in Texas with an estimated energy output of 60 GWh per year and an average utilization ratio of 0.32. This research indicates that applying GIS methodologies will be crucial in the growth of wind energy and efficiency in Texas.

? stability of wind turbine switching control

NASA Astrophysics Data System (ADS)

Palejiya, Dushyant; Shaltout, Mohamed; Yan, Zeyu; Chen, Dongmei

2015-01-01

In order to maximise the wind energy capture, wind turbines are operated at variable speeds. Depending on the wind speed, a turbine switches between two operating modes: a low wind speed mode and a high wind speed mode. During the low wind speed mode, the control objective is to maximise wind energy capture by controlling both the blade pitch angle and the electrical generator torque. During the high wind speed mode, the control goal is to maintain the rated power generation by only adjusting the blade pitch angle. This paper establishes the stability criteria for the switching operation of wind turbines using ? gain under the nonlinear control framework. Also, the performance of the wind turbine system is analysed by using the step response, a well-known measure for second-order linear systems.

Radar-cross-section reduction of wind turbines. part 1.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brock, Billy C.; Loui, Hung; McDonald, Jacob J.

2012-03-05

In recent years, increasing deployment of large wind-turbine farms has become an issue of growing concern for the radar community. The large radar cross section (RCS) presented by wind turbines interferes with radar operation, and the Doppler shift caused by blade rotation causes problems identifying and tracking moving targets. Each new wind-turbine farm installation must be carefully evaluated for potential disruption of radar operation for air defense, air traffic control, weather sensing, and other applications. Several approaches currently exist to minimize conflict between wind-turbine farms and radar installations, including procedural adjustments, radar upgrades, and proper choice of low-impact wind-farm sites,more » but each has problems with limited effectiveness or prohibitive cost. An alternative approach, heretofore not technically feasible, is to reduce the RCS of wind turbines to the extent that they can be installed near existing radar installations. This report summarizes efforts to reduce wind-turbine RCS, with a particular emphasis on the blades. The report begins with a survey of the wind-turbine RCS-reduction literature to establish a baseline for comparison. The following topics are then addressed: electromagnetic model development and validation, novel material development, integration into wind-turbine fabrication processes, integrated-absorber design, and wind-turbine RCS modeling. Related topics of interest, including alternative mitigation techniques (procedural, at-the-radar, etc.), an introduction to RCS and electromagnetic scattering, and RCS-reduction modeling techniques, can be found in a previous report.« less

Modified Adaptive Control for Region 3 Operation in the Presence of Wind Turbine Structural Modes

NASA Technical Reports Server (NTRS)

Frost, Susan Alane; Balas, Mark J.; Wright, Alan D.

2010-01-01

Many challenges exist for the operation of wind turbines in an efficient manner that is reliable and avoids component fatigue and failure. Turbines operate in highly turbulent environments resulting in aerodynamic loads that can easily excite turbine structural modes, possibly causing component fatigue and failure. Wind turbine manufacturers are highly motivated to reduce component fatigue and failure that can lead to loss of revenue due to turbine down time and maintenance costs. The trend in wind turbine design is toward larger, more flexible turbines that are ideally suited to adaptive control methods due to the complexity and expense required to create accurate models of their dynamic characteristics. In this paper, we design an adaptive collective pitch controller for a high-fidelity simulation of a utility-scale, variable-speed horizontal axis wind turbine operating in Region 3. The objective of the adaptive pitch controller is to regulate generator speed, accommodate wind gusts, and reduce the excitation of structural modes in the wind turbine. The control objective is accomplished by collectively pitching the turbine blades. The adaptive collective pitch controller for Region 3 was compared in simulations with a baseline classical Proportional Integrator (PI) collective pitch controller. The adaptive controller will demonstrate the ability to regulate generator speed in Region 3, while accommodating gusts, and reducing the excitation of certain structural modes in the wind turbine.

Large wind turbine generators

NASA Technical Reports Server (NTRS)

Thomas, R. L.; Donovon, R. M.

1978-01-01

The development associated with large wind turbine systems is briefly described. The scope of this activity includes the development of several large wind turbines ranging in size from 100 kW to several megawatt levels. A description of the wind turbine systems, their programmatic status and a summary of their potential costs is included.

An Evaluation of Wind Turbine Technology at Peterson Air Force Base

DTIC Science & Technology

2005-03-01

by the wind speed. Darrieus turbines are ordinarily inexpensive and are used for electricity generation and irrigation. One advantage to a...AN EVALUATION OF WIND TURBINE TECHNOLOGY...02 AN EVALUATION OF WIND TURBINE TECHNOLOGY AT PETERSON AIR FORCE BASE THESIS Presented to the Faculty Department of

Predicting Noise From Wind Turbines

NASA Technical Reports Server (NTRS)

Grosveld, Ferdinand W.

1990-01-01

Computer program WINDY predicts broadband noise spectra of horizontal-axis wind-turbine generators. Enables adequate assessment of impact of broadband wind-turbine noise. Effects of turbulence, trailing-edge wakes, and bluntness taken into account. Program has practical application in design and siting of wind-turbine machines acceptable to community. Written in GW-Basic.

77 FR 1498 - Draft Environmental Assessment and Proposed Single-Species Habitat Conservation Plan for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-10

... wind turbines and associated facilities and access roads, maintenance of the wind turbines and... include constructing and installing the wind turbines and associated electrical facilities and access... new 230- kilovolt substation (to be built on an existing pad), maintaining the new wind turbines and...

75 FR 4414 - Wind Turbine Guidelines Advisory Committee; Announcement of Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-27

...] Wind Turbine Guidelines Advisory Committee; Announcement of Public Meeting AGENCY: Fish and Wildlife... (Service), will host a Wind Turbine Guidelines Advisory Committee (Committee) meeting March 2- 4, 2010. The.../wind_turbine_advisory_committee.html , by February 23, 2010. Seating is limited due to room capacity...

New insights on the interaction between atmospheric flow and a full-scale 2.5 MW wind turbine

NASA Astrophysics Data System (ADS)

Chamorro, L. P.; Lee, S.; Olsen, D.; Milliren, C.; Marr, J.; Arndt, R.; Sotiropoulos, F.

2012-12-01

Power fluctuations and fatigue loads are among the most significant problems that wind turbines face throughout their lifetime. Atmospheric turbulence is the common driving mechanism that triggers instabilities on these quantities. Reducing the effects of the fluctuating flow on wind turbines is quite challenging due to the wide variety of length scales present in the boundary layer flow. Each group of these scales, which range from the order of a millimeter to kilometer and larger, plays a characteristic and distinctive role on the performance and structural reliability of wind turbines. This study seeks to contribute toward the understanding on the complex scale-to-scale interaction between wind turbine and flow turbulence. Novel insights into the physical mechanisms that govern the flow/turbine interaction will be discussed. To tackle the problem, we investigate the unsteady behavior of a full-scale 2.5 MW wind turbine under nearly neutral thermal stratification. The study is performed in the Eolos Wind Energy Research Field Station of the University of Minnesota. An instrumented 130 meter meteorological tower located upstream of a Clipper Liberty C96 wind turbine is used to characterize the turbulent flow and atmospheric conditions right upstream of the wind turbine. High resolution and synchronous measurements of the approach wind velocity at several heights, turbine power and strain at the tower foundation are used to determine the scale-to-scale interaction between flow and the wind turbine performance and its physical structure. The spectral distribution of the fluctuating turbine power and instantaneous stresses will be discussed in detail. Characteristic length scales playing a key role on the dynamics of the wind turbine as well as the distinctive effects of flow coherent motions and strong intermittent gusts will also be addressed. Funding was provided by the U.S. Department of Energy (DE-EE0002980) and Xcel Energy through the Renewable Development Fund (grant RD3-42).

Dynamics and stability of wind turbine generators

NASA Technical Reports Server (NTRS)

Hinrichsen, E. N.; Nolan, P. J.

1981-01-01

Synchronous and induction generators are considered. A comparison is made between wind turbines, steam, and hydro units. The unusual phenomena associated with wind turbines are emphasized. The general control requirements are discussed, as well as various schemes for torsional damping such as speed sensitive stabilizer and blade pitch control. Integration between adjacent wind turbines in a wind farm is also considered.

Wind Power Utilization Guide.

DTIC Science & Technology

1981-09-01

The expres- sions for the rotor torque for a Darrieus machine can be found in Reference 4.16. The Darrieus wind turbine offers the following... turbine generators, wind -driven turbines , power conditioning, wind power, energy conservation, windmills, economic ana \\sis. 20 ABS 1"ACT (Conti,on... turbines , power conditioning requirements, siting requirements, and the economics of wind power under different conditions. Three examples are given to

Systems Engineering Models and Tools | Wind | NREL

Science.gov Websites

(tm)) that provides wind turbine and plant engineering and cost models for holistic system analysis turbine/component models and wind plant analysis models that the systems engineering team produces. If you integrated modeling of wind turbines and plants. It provides guidance for overall wind turbine and plant

Spatial-temporal analysis of coherent offshore wind field structures measured by scanning Doppler-lidar

NASA Astrophysics Data System (ADS)

Valldecabres, L.; Friedrichs, W.; von Bremen, L.; Kühn, M.

2016-09-01

An analysis of the spatial and temporal power fluctuations of a simplified wind farm model is conducted on four offshore wind fields data sets, two from lidar measurements and two from LES under unstable and neutral atmospheric conditions. The integral length scales of the horizontal wind speed computed in the streamwise and the cross-stream direction revealed the elongation of the structures in the direction of the mean flow. To analyse the effect of the structures on the power output of a wind turbine, the aggregated equivalent power of two wind turbines with different turbine spacing in the streamwise and cross-stream direction is analysed at different time scales under 10 minutes. The fact of considering the summation of the power of two wind turbines smooths out the fluctuations of the power output of a single wind turbine. This effect, which is stronger with increasing spacing between turbines, can be seen in the aggregation of the power of two wind turbines in the streamwise direction. Due to the anti-correlation of the coherent structures in the cross-stream direction, this smoothing effect is stronger when the aggregated power is computed with two wind turbines aligned orthogonally to the mean flow direction.

Contingency power for small turboshaft engines using water injection into turbine cooling air

NASA Technical Reports Server (NTRS)

Biesiadny, Thomas J.; Klann, Gary A.; Clark, David A.; Berger, Brett

1987-01-01

Because of one engine inoperative requirements, together with hot-gas reingestion and hot day, high altitude takeoff situations, power augmentation for multiengine rotorcraft has always been of critical interest. However, power augmentation using overtemperature at the turbine inlet will shorten turbine life unless a method of limiting thermal and mechanical stresses is found. A possible solution involves allowing the turbine inlet temperature to rise to augment power while injecting water into the turbine cooling air to limit hot-section metal temperatures. An experimental water injection device was installed in an engine and successfully tested. Although concern for unprotected subcomponents in the engine hot section prevented demonstration of the technique's maximum potential, it was still possible to demonstrate increases in power while maintaining nearly constant turbine rotor blade temperature.

Dissipation of turbulence in the wake of a wind turbine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lundquist, J. K.; Bariteau, L.

The wake of a wind turbine is characterized by increased turbulence and decreased wind speed. Turbines are generally deployed in large groups in wind farms, and so the behaviour of an individual wake as it merges with other wakes and propagates downwind is critical in assessing wind-farm power production. This evolution depends on the rate of turbulence dissipation in the wind-turbine wake, which has not been previously quantified in field-scale measurements. In situ measurements of winds and turbulence dissipation from the wake region of a multi-MW turbine were collected using a tethered lifting system (TLS) carrying a payload of high-ratemore » turbulence probes. Ambient flow measurements were provided from sonic anemometers on a meteorological tower located near the turbine. Good agreement between the tower measurements and the TLS measurements was established for a case without a wind-turbine wake. When an operating wind turbine is located between the tower and the TLS so that the wake propagates to the TLS, the TLS measures dissipation rates one to two orders of magnitude higher in the wake than outside of the wake. These data, collected between two and three rotor diameters D downwind of the turbine, document the significant enhancement of turbulent kinetic energy dissipation rate within the wind-turbine wake. These wake measurements suggest that it may be useful to pursue modelling approaches that account for enhanced dissipation. Furthermore. comparisons of wake and non-wake dissipation rates to mean wind speed, wind-speed variance, and turbulence intensity are presented to facilitate the inclusion of these measurements in wake modelling schemes.« less

Dissipation of Turbulence in the Wake of a Wind Turbine

NASA Astrophysics Data System (ADS)

Lundquist, J. K.; Bariteau, L.

2015-02-01

The wake of a wind turbine is characterized by increased turbulence and decreased wind speed. Turbines are generally deployed in large groups in wind farms, and so the behaviour of an individual wake as it merges with other wakes and propagates downwind is critical in assessing wind-farm power production. This evolution depends on the rate of turbulence dissipation in the wind-turbine wake, which has not been previously quantified in field-scale measurements. In situ measurements of winds and turbulence dissipation from the wake region of a multi-MW turbine were collected using a tethered lifting system (TLS) carrying a payload of high-rate turbulence probes. Ambient flow measurements were provided from sonic anemometers on a meteorological tower located near the turbine. Good agreement between the tower measurements and the TLS measurements was established for a case without a wind-turbine wake. When an operating wind turbine is located between the tower and the TLS so that the wake propagates to the TLS, the TLS measures dissipation rates one to two orders of magnitude higher in the wake than outside of the wake. These data, collected between two and three rotor diameters downwind of the turbine, document the significant enhancement of turbulent kinetic energy dissipation rate within the wind-turbine wake. These wake measurements suggest that it may be useful to pursue modelling approaches that account for enhanced dissipation. Comparisons of wake and non-wake dissipation rates to mean wind speed, wind-speed variance, and turbulence intensity are presented to facilitate the inclusion of these measurements in wake modelling schemes.

Dissipation of turbulence in the wake of a wind turbine

DOE PAGES

Lundquist, J. K.; Bariteau, L.

2014-11-06

The wake of a wind turbine is characterized by increased turbulence and decreased wind speed. Turbines are generally deployed in large groups in wind farms, and so the behaviour of an individual wake as it merges with other wakes and propagates downwind is critical in assessing wind-farm power production. This evolution depends on the rate of turbulence dissipation in the wind-turbine wake, which has not been previously quantified in field-scale measurements. In situ measurements of winds and turbulence dissipation from the wake region of a multi-MW turbine were collected using a tethered lifting system (TLS) carrying a payload of high-ratemore » turbulence probes. Ambient flow measurements were provided from sonic anemometers on a meteorological tower located near the turbine. Good agreement between the tower measurements and the TLS measurements was established for a case without a wind-turbine wake. When an operating wind turbine is located between the tower and the TLS so that the wake propagates to the TLS, the TLS measures dissipation rates one to two orders of magnitude higher in the wake than outside of the wake. These data, collected between two and three rotor diameters D downwind of the turbine, document the significant enhancement of turbulent kinetic energy dissipation rate within the wind-turbine wake. These wake measurements suggest that it may be useful to pursue modelling approaches that account for enhanced dissipation. Furthermore. comparisons of wake and non-wake dissipation rates to mean wind speed, wind-speed variance, and turbulence intensity are presented to facilitate the inclusion of these measurements in wake modelling schemes.« less

A wind-tunnel investigation of wind-turbine wakes in different yawed and loading conditions

NASA Astrophysics Data System (ADS)

Bastankhah, Majid; Porté-Agel, Fernando

2015-04-01

Wind-turbine wakes have negative effects on wind-farm performance. They are associated with: (a) the velocity deficit, which reduces the generated power of downwind turbines; and (b) the turbulence level, which increases the fatigue loads on downwind turbines. Controlling the yaw angle of turbines can potentially improve the performance of wind farms by deflecting the wake away from downwind turbines. However, except for few studies, wakes of yawed turbines still suffer from the lack of systematic research. To fill this research gap, we performed wind-tunnel experiments in the recirculating boundary-layer wind tunnel at the WIRE Laboratory of EPFL to better understand the wakes of yawed turbines. High-resolution stereoscopic particle image-velocimetry (S-PIV) was used to measure three velocity components in a horizontal plane located downwind of a horizontal-axis, three-blade model turbine. A servo-controller was connected to the DC generator of the turbine, which allowed us to apply different loadings. The power and thrust coefficients of the turbine were also measured for each case. These power and thrust measurements together with the highly-resolved flow measurements enabled us to study different wake characteristics such as the energy entrainment from the outer flow into the wake, the wake deflection and the helicoidal tip vortices for yawed turbines.

FY17 Accomplishments - Testing Facilities and Capabilities at SWiFT, SNL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berg, Jonathan Charles

The Scaled Wind Farm Technologies (SWiFT) facility operated by Sandia National Laboratories (SNL) has, in support of the Atmosphere to electrons (A2e) research program, acquired measurements of wind turbine wake dynamics under various atmospheric conditions and while interacting with a downstream wind turbine. SNL researchers, in collaboration with National Renewable Energy Laboratory (NREL) researchers, installed a customized LIDAR system created by the Technical University of Denmark (DTU) in one of the SWiFT wind turbines (Figure 1) and operated that turbine with intentional yaw-versus-winddirection misalignment to study the behavior of the turbine wake under numerous combinations of atmospheric conditions and turbinemore » yaw offsets. The DTU-customized LIDAR provided detailed measurements of the wake’s shape and location at many distances downwind of the turbine (Figure 2). These measurements will benefit wind energy researchers looking to understand wind turbine wake behavior and improve modeling and simulation of wake dynamics, including the “wake steering” affect that is observed when turbine yaw offset is controlled. During the test campaign, two SWiFT wind turbines were operated at the same time to observe the influence of the turbines on each other as the wake of the upwind turbine was observed sweeping over and interacting with the downwind turbine.« less

Control of large wind turbine generators connected to utility networks

NASA Technical Reports Server (NTRS)

Hinrichsen, E. N.

1983-01-01

This is an investigation of the control requirements for variable pitch wind turbine generators connected to electric power systems. The requirements include operation in very small as well as very large power systems. Control systems are developed for wind turbines with synchronous, induction, and doubly fed generators. Simulation results are presented. It is shown how wind turbines and power system controls can be integrated. A clear distinction is made between fast control of turbine torque, which is a peculiarity of wind turbines, and slow control of electric power, which is a traditional power system requirement.

Airship-floated wind turbine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watson, W. K.

1985-01-01

A wind turbine, by use of a tethered airship for support, may be designed for the economical recovery of power at heights of 2,000 feet or more above ground, at which height power density in the wind is typically three times the power density available to a conventionally supported wind turbine. Means can be added to such an airship-floated wind turbine which will permit its generators to be used to meet load demand even during periods of little or no wind. Described to this end is a wind turbine system which combines, among other novel features: a novel tether linemore » system which provides access for men and materials to the supporting airship while in active service, a novel system for providing additional buoyant lift at the nose of the turbine-supporting airship to offset the vertical component of tension induced in the tether line by the downwind force exerted by the turbine blades, a novel bearing assembly at the nose of the supporting airship which permits the airship to rotate as a unit with the turbine it supports without causing a similar rotation of the tether line, a novel turbine airship structure which handles concentrated loads from the turbine efficiently and also permits the safe use of hydrogen for buoyancy, a novel ''space frame'' structure which supports the turbine blades and greatly reduces blade weight, a novel system for controlling turbine blade angle of incidence and for varying blade incidene in synchrony with blade angular position abut the turbine axis to provide greater control over airship movement, a novel system for locating propellor-driven generators out at the wind turbine perimeter and for using lightweight, high-RPM generators to produce electrical energy at a power line frequency, which greatly reduces the weight required to convert turbine blade torque into useful power, and a novel system for incorporating compressed air storage and combustion turbine components into the wind turbine's generator drive systems.« less

Constructing a Plastic Bottle Wind Turbine as a Practical Aid for Learning about Using Wind Energy to Generate Electricity

ERIC Educational Resources Information Center

Appleyard, S. J.

2009-01-01

A simple horizontal axis wind turbine can be easily constructed using a 1.5 l PET plastic bottle, a compact disc and a small dynamo. The turbine operates effectively at low wind speeds and has a rotational speed of 500 rpm at a wind speed of about 14 km h[superscript -1]. The wind turbine can be used to demonstrate the relationship between open…

An Assessment of Wind Plant Complex Flows Using Advanced Doppler Radar Measurements

NASA Astrophysics Data System (ADS)

Gunter, W. S.; Schroeder, J.; Hirth, B.; Duncan, J.; Guynes, J.

2015-12-01

As installed wind energy capacity continues to steadily increase, the need for comprehensive measurements of wind plant complex flows to further reduce the cost of wind energy has been well advertised by the industry as a whole. Such measurements serve diverse perspectives including resource assessment, turbine inflow and power curve validation, wake and wind plant layout model verification, operations and maintenance, and the development of future advanced wind plant control schemes. While various measurement devices have been matured for wind energy applications (e.g. meteorological towers, LIDAR, SODAR), this presentation will focus on the use of advanced Doppler radar systems to observe the complex wind flows within and surrounding wind plants. Advanced Doppler radars can provide the combined advantage of a large analysis footprint (tens of square kilometers) with rapid data analysis updates (a few seconds to one minute) using both single- and dual-Doppler data collection methods. This presentation demonstrates the utility of measurements collected by the Texas Tech University Ka-band (TTUKa) radars to identify complex wind flows occurring within and nearby operational wind plants, and provide reliable forecasts of wind speeds and directions at given locations (i.e. turbine or instrumented tower sites) 45+ seconds in advance. Radar-derived wind maps reveal commonly observed features such as turbine wakes and turbine-to-turbine interaction, high momentum wind speed channels between turbine wakes, turbine array edge effects, transient boundary layer flow structures (such as wind streaks, frontal boundaries, etc.), and the impact of local terrain. Operational turbine or instrumented tower data are merged with the radar analysis to link the observed complex flow features to turbine and wind plant performance.

Wake characteristics of wind turbines in utility-scale wind farms

NASA Astrophysics Data System (ADS)

Yang, Xiaolei; Foti, Daniel; Sotiropoulos, Fotis

2017-11-01

The dynamics of turbine wakes is affected by turbine operating conditions, ambient atmospheric turbulent flows, and wakes from upwind turbines. Investigations of the wake from a single turbine have been extensively carried out in the literature. Studies on the wake dynamics in utility-scale wind farms are relatively limited. In this work, we employ large-eddy simulation with an actuator surface or actuator line model for turbine blades to investigate the wake dynamics in utility-scale wind farms. Simulations of three wind farms, i.e., the Horns Rev wind farm in Denmark, Pleasant Valley wind farm in Minnesota, and the Vantage wind farm in Washington are carried out. The computed power shows a good agreement with measurements. Analysis of the wake dynamics in the three wind farms is underway and will be presented in the conference. This work was support by Xcel Energy (RD4-13). The computational resources were provided by National Renewable Energy Laboratory.

Wind Turbine Controller to Mitigate Structural Loads on a Floating Wind Turbine Platform

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleming, Paul A.; Peiffer, Antoine; Schlipf, David

This paper summarizes the control design work that was performed to optimize the controller of a wind turbine on the WindFloat structure. The WindFloat is a semi-submersible floating platform designed to be a support structure for a multi-megawatt power-generating wind turbine. A controller developed for a bottom-fixed wind turbine configuration was modified for use when the turbine is mounted on the WindFloat platform. This results in an efficient platform heel resonance mitigation scheme. In addition several control modules, designed with a coupled linear model, were added to the fixed-bottom baseline controller. The approach was tested in a fully coupled nonlinearmore » aero-hydroelastic simulation tool in which wind and wave disturbances were modeled. This testing yielded significant improvements in platform global performance and tower-base-bending loading.« less

Large wind turbines: A utility option for the generation of electricity

NASA Technical Reports Server (NTRS)

Robbins, W. H.; Thomas, R. L.; Baldwin, D. H.

1980-01-01

The wind resource is such that wind energy generation has the potential to save 6-7 quads of energy nationally. Thus, the Federal Government is sponsoring and encouraging the development of cost effective and reliable wind turbines. One element of the Federal Wind Energy Programs, Large Horizontal Axis Wind Turbine Development, is managed by the NASA Lewis Research Center for the Department of Energy. There are several ongoing wind system development projects oriented primarily toward utility application within this program element. In addition, a comprehensive technology program supporting the wind turbine development projects is being conducted. An overview is presented of the NASA activities with emphasis on application of large wind turbines for generation of electricity by utility systems.

Experimental Study on New Multi-Column Tension-Leg-Type Floating Wind Turbine

NASA Astrophysics Data System (ADS)

Zhao, Yong-sheng; She, Xiao-he; He, Yan-ping; Yang, Jian-min; Peng, Tao; Kou, Yu-feng

2018-04-01

Deep-water regions often have winds favorable for offshore wind turbines, and floating turbines currently show the greatest potential to exploit such winds. This work established proper scaling laws for model tests, which were then implemented in the construction of a model wind turbine with optimally designed blades. The aerodynamic, hydrodynamic, and elastic characteristics of the proposed new multi-column tension-leg-type floating wind turbine (WindStar TLP system) were explored in the wave tank testing of a 1:50 scale model at the State Key Laboratory of Ocean Engineering at Shanghai Jiao Tong University. Tests were conducted under conditions of still water, white noise waves, irregular waves, and combined wind, wave, and current loads. The results established the natural periods of the motion, damping, motion response amplitude operators, and tendon tensions of the WindStar TLP system under different environmental conditions, and thus could serve as a reference for further research. Key words: floating wind turbine, model test, WindStar TLP, dynamic response

Establishment of a National Wind Energy Center at University of Houston

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Su Su

The DOE-supported project objectives are to: establish a national wind energy center (NWEC) at University of Houston and conduct research to address critical science and engineering issues for the development of future large MW-scale wind energy production systems, especially offshore wind turbines. The goals of the project are to: (1) establish a sound scientific/technical knowledge base of solutions to critical science and engineering issues for developing future MW-scale large wind energy production systems, (2) develop a state-of-the-art wind rotor blade research facility at the University of Houston, and (3) through multi-disciplinary research, introducing technology innovations on advanced wind-turbine materials, processing/manufacturingmore » technology, design and simulation, testing and reliability assessment methods related to future wind turbine systems for cost-effective production of offshore wind energy. To achieve the goals of the project, the following technical tasks were planned and executed during the period from April 15, 2010 to October 31, 2014 at the University of Houston: (1) Basic research on large offshore wind turbine systems (2) Applied research on innovative wind turbine rotors for large offshore wind energy systems (3) Integration of offshore wind-turbine design, advanced materials and manufacturing technologies (4) Integrity and reliability of large offshore wind turbine blades and scaled model testing (5) Education and training of graduate and undergraduate students and post- doctoral researchers (6) Development of a national offshore wind turbine blade research facility The research program addresses both basic science and engineering of current and future large wind turbine systems, especially offshore wind turbines, for MW-scale power generation. The results of the research advance current understanding of many important scientific issues and provide technical information for solving future large wind turbines with advanced design, composite materials, integrated manufacturing, and structural reliability and integrity. The educational program have trained many graduate and undergraduate students and post-doctoral level researchers to learn critical science and engineering of wind energy production systems through graduate-level courses and research, and participating in various projects in center’s large multi-disciplinary research. These students and researchers are now employed by the wind industry, national labs and universities to support the US and international wind energy industry. The national offshore wind turbine blade research facility developed in the project has been used to support the technical and training tasks planned in the program to accomplish their goals, and it is a national asset which is available for used by domestic and international researchers in the wind energy arena.« less

Integrating Systems Health Management with Adaptive Controls for a Utility-Scale Wind Turbine

NASA Technical Reports Server (NTRS)

Frost, Susan A.; Goebel, Kai; Trinh, Khanh V.; Balas, Mark J.; Frost, Alan M.

2011-01-01

Increasing turbine up-time and reducing maintenance costs are key technology drivers for wind turbine operators. Components within wind turbines are subject to considerable stresses due to unpredictable environmental conditions resulting from rapidly changing local dynamics. Systems health management has the aim to assess the state-of-health of components within a wind turbine, to estimate remaining life, and to aid in autonomous decision-making to minimize damage. Advanced adaptive controls can provide the mechanism to enable optimized operations that also provide the enabling technology for Systems Health Management goals. The work reported herein explores the integration of condition monitoring of wind turbine blades with contingency management and adaptive controls. Results are demonstrated using a high fidelity simulator of a utility-scale wind turbine.

Effects of wind turbines on upland nesting birds in Conservation Reserve Program grasslands

USGS Publications Warehouse

Leddy, K.L.; Higgins, K.F.; Naugle, D.E.

1999-01-01

Grassland passerines were surveyed during summer 1995 on the Buffalo Ridge Wind Resource Area in southwestern Minnesota to determine the relative influence of wind turbines on overall densities of upland nesting birds in Conservation Reserve Program (CRP) grasslands. Birds were surveyed along 40 m fixed width transects that were placed along wind turbine strings within three CRP fields and in three CRP fields without turbines. Conservation Reserve Program grasslands without turbines and areas located 180 m from turbines supported higher densities (261.0-312.5 males/100 ha) of grassland birds than areas within 80 m of turbines (58.2-128.0 males/100 ha). Human disturbance, turbine noise, and physical movements of turbines during operation may have disturbed nesting birds. We recommend that wind turbines be placed within cropland habitats that support lower densities of grassland passerines than those found in CRP grasslands.

CWEX (Crop/Wind-Energy Experiment): Measurements of the interaction between crop agriculture and wind power

NASA Astrophysics Data System (ADS)

Rajewski, Daniel Andrew

The current expansion of wind farms in the U.S. Midwest promotes an alternative renewable energy portfolio to conventional energy sources derived from fossil fuels. The construction of wind turbines and large wind farms within several millions of cropland acres creates a unique interaction between two unlike energy sources: electric generation by wind and bio-fuel production derived from crop grain and plant tissues. Wind turbines produce power by extracting mean wind speed and converting a portion of the flow to turbulence downstream of each rotor. Turbine-scale turbulence modifies fluxes of momentum, heat, moisture, and other gaseous constituents (e.g. carbon dioxide) between the crop canopy and the atmospheric boundary layer. Conversely, crop surfaces and tillage elements produce drag on the hub-height wind resource, and the release of sensible and latent heat flux from the canopy or soil influences the wind speed profile. The Crop-Wind Energy Experiment (CWEX) measured momentum, energy, and CO2 fluxes at several locations within the leading line of turbines in a large operational wind farm, and overall turbines promote canopy mixing of wind speed, temperature, moisture, and carbon dioxide in both the day and night. Turbine-generated perturbations of these fluxes are dependent on several factors influencing the turbine operation (e.g. wind speed, wind direction, stability, orientation of surrounding turbines within a wind park) and the cropland surface (e.g. crop type and cultivar, planting density, chemical application, and soil composition and drainage qualities). Additional strategies are proposed for optimizing the synergy between crop and wind power.

Method and apparatus for wind turbine braking

DOEpatents

Barbu, Corneliu [Laguna Hills, CA; Teichmann, Ralph [Nishkayuna, NY; Avagliano, Aaron [Houston, TX; Kammer, Leonardo Cesar [Niskayuna, NY; Pierce, Kirk Gee [Simpsonville, SC; Pesetsky, David Samuel [Greenville, SC; Gauchel, Peter [Muenster, DE

2009-02-10

A method for braking a wind turbine including at least one rotor blade coupled to a rotor. The method includes selectively controlling an angle of pitch of the at least one rotor blade with respect to a wind direction based on a design parameter of a component of the wind turbine to facilitate reducing a force induced into the wind turbine component as a result of braking.

Mod-2 wind turbine system development. Volume 2: Detailed report

NASA Technical Reports Server (NTRS)

1982-01-01

Progress in the design, fabrication, and testing of a wind turbine system is reported. The development of the MOD-2 wind turbine through acceptance testing and initial operational evaluation is documented. The MOD-2 project intends to develop early commercialization of wind energy. The first wind turbine farm (three MOD-2 units) are now being operated at the Bonneville Power Administration site near Goldendale, Washington.

The Inception of OMA in the Development of Modal Testing Technology for Wind Turbines

NASA Technical Reports Server (NTRS)

James, George H., III; Carne. Thomas G.

2008-01-01

Wind turbines are immense, flexible structures with aerodynamic forces acting on the rotating blades at harmonics of the turbine rotational frequency, which are comparable to the modal frequencies of the structure. Predicting and experimentally measuring the modal frequencies of wind turbines has been important to their successful design and operation. Performing modal tests on wind turbine structures over 100 meters tall is a substantial challenge, which has inspired innovative developments in modal test technology. For wind turbines, a further complication is that the modal frequencies are dependent on the turbine rotation speed. The history and development of a new technique for acquiring the modal parameters using output-only response data, called the Natural Excitation Technique (NExT), will be reviewed, showing historical tests and techniques. The initial attempts at output-only modal testing began in the late 1980's with the development of NExT in the 1990's. NExT was a predecessor to OMA, developed to overcome these challenges of testing immense structures excited with environmental inputs. We will trace the difficulties and successes of wind turbine modal testing from 1982 to the present. Keywords: OMA, Modal Analysis, NExT, Wind Turbines, Wind Excitation

Analysis of turbine-grid interaction of grid-connected wind turbine using HHT

NASA Astrophysics Data System (ADS)

Chen, A.; Wu, W.; Miao, J.; Xie, D.

2018-05-01

This paper processes the output power of the grid-connected wind turbine with the denoising and extracting method based on Hilbert Huang transform (HHT) to discuss the turbine-grid interaction. At first, the detailed Empirical Mode Decomposition (EMD) and the Hilbert Transform (HT) are introduced. Then, on the premise of decomposing the output power of the grid-connected wind turbine into a series of Intrinsic Mode Functions (IMFs), energy ratio and power volatility are calculated to detect the unessential components. Meanwhile, combined with vibration function of turbine-grid interaction, data fitting of instantaneous amplitude and phase of each IMF is implemented to extract characteristic parameters of different interactions. Finally, utilizing measured data of actual parallel-operated wind turbines in China, this work accurately obtains the characteristic parameters of turbine-grid interaction of grid-connected wind turbine.

Duration Test Report for the Entegrity EW50 Wind Turbine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, J.; Huskey, A.; Jager, D.

2012-12-01

This report summarizes the results of a duration test that NREL conducted on the Entegrity EW50 wind turbine. This test was conducted in accordance with the International Electrotechnical Commissions' (IEC) standard, Wind Turbine Generator System Part 2: Design requirements for small wind turbines, IEC 61400-2 Ed.2.0, 2006-03.

76 FR 10328 - Grant of Authority for Subzone Status; Vestas Nacelles America, Inc. (Wind Turbine Nacelles, Hubs...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-24

... Status; Vestas Nacelles America, Inc. (Wind Turbine Nacelles, Hubs, Blades and Towers), Brighton, Denver...-purpose subzone at the wind turbine nacelle, hub, blade and tower manufacturing and warehousing facilities... status for activity related to the manufacturing and warehousing of wind turbine nacelles, hubs, blades...

Turbulence effects on a full-scale 2.5 MW horizontal axis wind turbine

NASA Astrophysics Data System (ADS)

Chamorro, Leonardo; Lee, Seung-Jae; Olsen, David; Milliren, Chris; Marr, Jeff; Arndt, Roger; Sotiropoulos, Fotis

2012-11-01

Power fluctuations and fatigue loads are among the most significant problems that wind turbines face throughout their lifetime. Turbulence is the common driving mechanism that triggers instabilities on these quantities. We investigate the complex response of a full-scale 2.5 MW wind turbine under nearly neutral thermal stratification. The study is performed in the EOLOS Wind Energy Research Field Station of the University of Minnesota. An instrumented 130 meter meteorological tower located upstream of a Clipper Liberty C96 wind turbine is used to characterize the turbulent flow and atmospheric conditions right upstream of the wind turbine. High resolution and synchronous measurements of the wind velocity, turbine power and strain at the tower foundation are used to determine the scale-to-scale interaction between flow and the wind turbine. The structure of the fluctuating turbine power and instantaneous stresses are studied in detail. Important insights about the role of turbulent and coherent motions as well as strong intermittent gusts will be discussed. Funding was provided by Department of Energy DOE (DE-EE0002980) and Xcel Energy through the Renewable Development Fund (grant RD3-42).

Offshore Wind Turbines - Estimated Noise from Offshore Wind Turbine, Monhegan Island, Maine: Environmental Effects of Offshore Wind Energy Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aker, Pamela M.; Jones, Anthony M.; Copping, Andrea E.

2010-11-23

Deep C Wind, a consortium headed by the University of Maine will test the first U.S. offshore wind platforms in 2012. In advance of final siting and permitting of the test turbines off Monhegan Island, residents of the island off Maine require reassurance that the noise levels from the test turbines will not disturb them. Pacific Northwest National Laboratory, at the request of the University of Maine, and with the support of the U.S. Department of Energy Wind Program, modeled the acoustic output of the planned test turbines.

Utility operational experience on the NASA/DOE MOD-0A 200-kW wind turbine

NASA Technical Reports Server (NTRS)

Glasgow, J. C.; Robbins, W. H.

1979-01-01

The Mod-0A 200 wind turbine was designed and fabricated as part of the Federal Wind Energy Program. Early wind turbine operation and performance data were obtained while gaining initial experience in the operation of large, horizontal axis wind turbines in typical utility environments. The Mod-0A wind turbine was turned over to the Town of Clayton Light and Water Plant, Clayton, NM, for utility operation and on December 31, 1978, the machine had completed ten months of utility operation. The machine is described and the recent operational experience at Clayton, NMis documented.

The Effect of Wind-Turbine Wakes on Summertime US Midwest Atmospheric Wind Profiles as Observed with Ground-Based Doppler Lidar

NASA Astrophysics Data System (ADS)

Rhodes, Michael E.; Lundquist, Julie K.

2013-07-01

We examine the influence of a modern multi-megawatt wind turbine on wind and turbulence profiles three rotor diameters (D) downwind of the turbine. Light detection and ranging (lidar) wind-profile observations were collected during summer 2011 in an operating wind farm in central Iowa at 20-m vertical intervals from 40 to 220 m above the surface. After a calibration period during which two lidars were operated next to each other, one lidar was located approximately 2D directly south of a wind turbine; the other lidar was moved approximately 3D north of the same wind turbine. Data from the two lidars during southerly flow conditions enabled the simultaneous capture of inflow and wake conditions. The inflow wind and turbulence profiles exhibit strong variability with atmospheric stability: daytime profiles are well-mixed with little shear and strong turbulence, while nighttime profiles exhibit minimal turbulence and considerable shear across the rotor disk region and above. Consistent with the observations available from other studies and with wind-tunnel and large-eddy simulation studies, measurable reductions in wake wind-speeds occur at heights spanning the wind turbine rotor (43-117 m), and turbulent quantities increase in the wake. In generalizing these results as a function of inflow wind speed, we find the wind-speed deficit in the wake is largest at hub height or just above, and the maximum deficit occurs when wind speeds are below the rated speed for the turbine. Similarly, the maximum enhancement of turbulence kinetic energy and turbulence intensity occurs at hub height, although observations at the top of the rotor disk do not allow assessment of turbulence in that region. The wind shear below turbine hub height (quantified here with the power-law coefficient) is found to be a useful parameter to identify whether a downwind lidar observes turbine wake or free-flow conditions. These field observations provide data for validating turbine-wake models and wind-tunnel observations, and for guiding assessments of the impacts of wakes on surface turbulent fluxes or surface temperatures downwind of turbines.

Toward understanding the physical link between turbines and microclimate impacts from in situ measurements in a large wind farm

NASA Astrophysics Data System (ADS)

Rajewski, Daniel A.; Takle, Eugene S.; Prueger, John H.; Doorenbos, Russell K.

2016-11-01

Recent wind farm studies have revealed elevated nighttime surface temperatures but have not validated physical mechanisms that create the observed effects. We report measurements of concurrent differences in surface wind speed, temperature, fluxes, and turbulence upwind and downwind of two turbine lines at the windward edge of a utility-scale wind farm. On the basis of these measurements, we offer a conceptual model based on physical mechanisms of how wind farms affect their own microclimate. Periods of documented curtailment and zero-power production of the wind farm offer useful opportunities to rigorously evaluate the microclimate impact of both stationary and operating turbines. During an 80 min nighttime wind farm curtailment, we measured abrupt and large changes in turbulent fluxes of momentum and heat leeward of the turbines. At night, wind speed decreases in the near wake when turbines are off but abruptly increases when turbine operation is resumed. Our measurements are compared with Moderate Resolution Imaging Spectroradiometer Terra and Aqua satellite measurements reporting wind farms to have higher nighttime surface temperatures. We demonstrate that turbine wakes modify surface fluxes continuously through the night, with similar magnitudes during the Terra and Aqua transit periods. Cooling occurs in the near wake and warming in the far wake when turbines are on, but cooling is negligible when turbines are off. Wind speed and surface stratification have a regulating effect of enhancing or decreasing the impact on surface microclimate due to turbine wake effects.

Energy 101: Wind Turbines - 2014 Update

ScienceCinema

None

2018-05-11

See how wind turbines generate clean electricity from the power of wind. The video highlights the basic principles at work in wind turbines, and illustrates how the various components work to capture and convert wind energy to electricity. This updated version also includes information on the Energy Department's efforts to advance offshore wind power. Offshore wind energy footage courtesy of Vestas.

Dynamics modeling and loads analysis of an offshore floating wind turbine

NASA Astrophysics Data System (ADS)

Jonkman, Jason Mark

The vast deepwater wind resource represents a potential to use offshore floating wind turbines to power much of the world with renewable energy. Many floating wind turbine concepts have been proposed, but dynamics models, which account for the wind inflow, aerodynamics, elasticity, and controls of the wind turbine, along with the incident waves, sea current, hydrodynamics, and platform and mooring dynamics of the floater, were needed to determine their technical and economic feasibility. This work presents the development of a comprehensive simulation tool for modeling the coupled dynamic response of offshore floating wind turbines, the verification of the simulation tool through model-to-model comparisons, and the application of the simulation tool to an integrated loads analysis for one of the promising system concepts. A fully coupled aero-hydro-servo-elastic simulation tool was developed with enough sophistication to address the limitations of previous frequency- and time-domain studies and to have the features required to perform loads analyses for a variety of wind turbine, support platform, and mooring system configurations. The simulation capability was tested using model-to-model comparisons. The favorable results of all of the verification exercises provided confidence to perform more thorough analyses. The simulation tool was then applied in a preliminary loads analysis of a wind turbine supported by a barge with catenary moorings. A barge platform was chosen because of its simplicity in design, fabrication, and installation. The loads analysis aimed to characterize the dynamic response and to identify potential loads and instabilities resulting from the dynamic couplings between the turbine and the floating barge in the presence of combined wind and wave excitation. The coupling between the wind turbine response and the barge-pitch motion, in particular, produced larger extreme loads in the floating turbine than experienced by an equivalent land-based turbine. Instabilities were also found in the system. The influence of conventional wind turbine blade-pitch control actions on the pitch damping of the floating turbine was also assessed. Design modifications for reducing the platform motions, improving the turbine response, and eliminating the instabilities are suggested. These suggestions are aimed at obtaining cost-effective designs that achieve favorable performance while maintaining structural integrity.

Visualization and Analysis of Vortex-Turbine Intersections in Wind Farms.

PubMed

Shafii, Sohail; Obermaier, Harald; Linn, Rodman; Koo, Eunmo; Hlawitschka, Mario; Garth, Christoph; Hamann, Bernd; Joy, Kenneth

2013-02-13

Characterizing the interplay between the vortices and forces acting on a wind turbine's blades in a qualitative and quantitative way holds the potential for significantly improving large wind turbine design. The paper introduces an integrated pipeline for highly effective wind and force field analysis and visualization. We extract vortices induced by a turbine's rotation in a wind field, and characterize vortices in conjunction with numerically simulated forces on the blade surfaces as these vortices strike another turbine's blades downstream. The scientifically relevant issue to be studied is the relationship between the extracted, approximate locations on the blades where vortices strike the blades and the forces that exist in those locations. This integrated approach is used to detect and analyze turbulent flow that causes local impact on the wind turbine blade structure. The results that we present are based on analyzing the wind and force field data sets generated by numerical simulations, and allow domain scientists to relate vortex-blade interactions with power output loss in turbines and turbine life-expectancy. Our methods have the potential to improve turbine design in order to save costs related to turbine operation and maintenance.

Analytical Model for Mean Flow and Fluxes of Momentum and Energy in Very Large Wind Farms

NASA Astrophysics Data System (ADS)

Markfort, Corey D.; Zhang, Wei; Porté-Agel, Fernando

2018-01-01

As wind-turbine arrays continue to be installed and the array size continues to grow, there is an increasing need to represent very large wind-turbine arrays in numerical weather prediction models, for wind-farm optimization, and for environmental assessment. We propose a simple analytical model for boundary-layer flow in fully-developed wind-turbine arrays, based on the concept of sparsely-obstructed shear flows. In describing the vertical distribution of the mean wind speed and shear stress within wind farms, our model estimates the mean kinetic energy harvested from the atmospheric boundary layer, and determines the partitioning between the wind power captured by the wind turbines and that absorbed by the underlying land or water. A length scale based on the turbine geometry, spacing, and performance characteristics, is able to estimate the asymptotic limit for the fully-developed flow through wind-turbine arrays, and thereby determine if the wind-farm flow is fully developed for very large turbine arrays. Our model is validated using data collected in controlled wind-tunnel experiments, and its usefulness for the prediction of wind-farm performance and optimization of turbine-array spacing are described. Our model may also be useful for assessing the extent to which the extraction of wind power affects the land-atmosphere coupling or air-water exchange of momentum, with implications for the transport of heat, moisture, trace gases such as carbon dioxide, methane, and nitrous oxide, and ecologically important oxygen.

Damage detection of rotating wind turbine blades using local flexibility method and long-gauge fiber Bragg grating sensors

NASA Astrophysics Data System (ADS)

Hsu, Ting-Yu; Shiao, Shen-Yuan; Liao, Wen-I.

2018-01-01

Wind turbines are a cost-effective alternative energy source; however, their blades are susceptible to damage. Therefore, damage detection of wind turbine blades is of great importance for condition monitoring of wind turbines. Many vibration-based structural damage detection techniques have been proposed in the last two decades. The local flexibility method, which can determine local stiffness variations of beam-like structures by using measured modal parameters, is one of the most promising vibration-based approaches. The local flexibility method does not require a finite element model of the structure. A few structural modal parameters identified from the ambient vibration signals both before and after damage are required for this method. In this study, we propose a damage detection approach for rotating wind turbine blades using the local flexibility method based on the dynamic macro-strain signals measured by long-gauge fiber Bragg grating (FBG)-based sensors. A small wind turbine structure was constructed and excited using a shaking table to generate vibration signals. The structure was designed to have natural frequencies as close as possible to those of a typical 1.5 MW wind turbine in real scale. The optical fiber signal of the rotating blades was transmitted to the data acquisition system through a rotary joint fixed inside the hollow shaft of the wind turbine. Reversible damage was simulated by aluminum plates attached to some sections of the wind turbine blades. The damaged locations of the rotating blades were successfully detected using the proposed approach, with the extent of damage somewhat over-estimated. Nevertheless, although the specimen of wind turbine blades cannot represent a real one, the results still manifest that FBG-based macro-strain measurement has potential to be employed to obtain the modal parameters of the rotating wind turbines and then locations of wind turbine segments with a change of rigidity can be estimated effectively by utilizing these identified parameters.

Unsteady Flow in Different Atmospheric Boundary Layer Regimes and Its Impact on Wind-Turbine Performance

NASA Astrophysics Data System (ADS)

Gohari, Iman; Korobenko, Artem; Yan, Jinhui; Bazilevs, Yuri; Sarkar, Sutanu

2016-11-01

Wind is a renewable energy resource that offers several advantages including low pollutant emission and inexpensive construction. Wind turbines operate in conditions dictated by the Atmospheric Boundary Layer (ABL) and that motivates the study of coupling ABL simulations with wind turbine dynamics. The ABL simulations can be used for realistic modeling of the environment which, with the use of fluid-structure interaction, can give realistic predictions of extracted power, rotor loading, and blade structural response. The ABL simulations provide inflow boundary conditions to the wind-turbine simulator which uses arbitrary Lagrangian-Eulerian variational multiscale formulation. In the present work, ABL simulations are performed to examine two different scenarios: (i) A neutral ABL with zero heat-flux and inversion layer at 350m, in which the wind turbine experiences maximum mean shear; (2) A shallow ABL with the surface cooling-rate of -1 K/hr, in which the wind turbine experiences maximum mean velocity at the low-level-jet nose height. We will discuss differences in the unsteady flow between the two different ABL conditions and their impact on the performance of the wind turbine cluster in the coupled ABL-wind turbine simulations.

Crack detection on wind turbine blades in an operating environment using vibro-acoustic modulation technique

NASA Astrophysics Data System (ADS)

Kim, S.; Adams, D. E.; Sohn, H.

2013-01-01

As the wind power industry has grown rapidly in the recent decade, maintenance costs have become a significant concern. Due to the high repair costs for wind turbine blades, it is especially important to detect initial blade defects before they become structural failures leading to other potential failures in the tower or nacelle. This research presents a method of detecting cracks on wind turbine blades using the Vibo-Acoustic Modulation technique. Using Vibro-Acoustic Modulation, a crack detection test is conducted on a WHISPER 100 wind turbine in its operating environment. Wind turbines provide the ideal conditions in which to utilize Vibro-Acoustic Modulation because wind turbines experience large structural vibrations. The structural vibration of the wind turbine balde was used as a pumping signal and a PZT was used to generate the probing signal. Because the non-linear portion of the dynamic response is more sensitive to the presence of a crack than the environmental conditions or operating loads, the Vibro-Acoustic Modulation technique can provide a robust structural health monitoring approach for wind turbines. Structural health monitoring can significantly reduce maintenance costs when paired with predictive modeling to minimize unscheduled maintenance.

Large-Scale Wind Turbine Testing in the NASA 24.4m (80) by 36.6m(120) Wind Tunnel

NASA Technical Reports Server (NTRS)

Zell, Peter T.; Imprexia, Cliff (Technical Monitor)

2000-01-01

The 80- by 120-Foot Wind Tunnel at NASA Ames Research Center in California provides a unique capability to test large-scale wind turbines under controlled conditions. This special capability is now available for domestic and foreign entities wishing to test large-scale wind turbines. The presentation will focus on facility capabilities to perform wind turbine tests and typical research objectives for this type of testing.

Operating wind turbines in strong wind conditions by using feedforward-feedback control

NASA Astrophysics Data System (ADS)

Feng, Ju; Sheng, Wen Zhong

2014-12-01

Due to the increasing penetration of wind energy into power systems, it becomes critical to reduce the impact of wind energy on the stability and reliability of the overall power system. In precedent works, Shen and his co-workers developed a re-designed operation schema to run wind turbines in strong wind conditions based on optimization method and standard PI feedback control, which can prevent the typical shutdowns of wind turbines when reaching the cut-out wind speed. In this paper, a new control strategy combing the standard PI feedback control with feedforward controls using the optimization results is investigated for the operation of variable-speed pitch-regulated wind turbines in strong wind conditions. It is shown that the developed control strategy is capable of smoothening the power output of wind turbine and avoiding its sudden showdown at high wind speeds without worsening the loads on rotor and blades.

76 FR 490 - Marking Meteorological Evaluation Towers

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-05

... of energy generation. Wind energy, converted into electrical energy by wind turbines, is widely... turbine or wind farm, companies erect METs. These towers are used to gather wind data necessary for site... if the targeted area represents a potential location for the installation of wind turbines...

A coupled aero-structural model of a HAWT blade for dynamic load and response prediction in time-domain for health monitoring applications

NASA Astrophysics Data System (ADS)

Sauder, Heather Scot

To reach the high standards set for renewable energy production in the US and around the globe, wind turbines with taller towers and longer blades are being designed for onshore and offshore wind developments to capture more energy from higher winds aloft and a larger rotor diameter. However, amongst all the wind turbine components wind turbine blades are still the most prone to damage. Given that wind turbine blades experience dynamic loads from multiple sources, there is a need to be able to predict the real-time load, stress distribution and response of the blade in a given wind environment for damage, flutter and fatigue life predictions. Current methods of wind-induced response analysis for wind turbine blades use approximations that are not suitable for wind turbine blade airfoils which are thick, and therefore lead to inaccurate life predictions. Additionally, a time-domain formulation can prove to be especially advantageous for predicting aerodynamic loads on wind turbine blades since they operate in a turbulent atmospheric boundary layer. This will help to analyze the blades on wind turbines that operate individually or in a farm setting where they experience high turbulence in the wake of another wind turbine. A time-domain formulation is also useful for examining the effects of gusty winds that are transient in nature like in gust fronts, thunderstorms or extreme events such as hurricanes, microbursts, and tornadoes. Time-domain methods present the opportunity for real-time health monitoring strategies that can easily be used with finite element methods for prediction of fatigue life or onset of flutter instability. The purpose of the proposed work is to develop a robust computational model to predict the loads, stresses and response of a wind turbine blade in operating and extreme wind conditions. The model can be used to inform health monitoring strategies for preventative maintenance and provide a realistic number of stress cycles that the blade will experience for fatigue life prediction procedures. To fill in the gaps in the existing knowledge and meet the overall goal of the proposed research, the following objectives were accomplished: (a) improve the existing aeroelastic (motion- and turbulence-induced) load models to predict the response of wind turbine blade airfoils to understand its behavior in turbulent wind, (b) understand, model and predict the response of wind turbine blades in transient or gusty wind, boundary-layer wind and incoherent wind over the span of the blade, (c) understand the effects of aero-structural coupling between the along-wind, cross-wind and torsional vibrations, and finally (d) develop a computational tool using the improved time-domain load model to predict the real-time load, stress distribution and response of a given wind turbine blade during operating and parked conditions subject to a specific wind environment both in a short and long term for damage, flutter and fatigue life predictions.

Final Technical Report Recovery Act: Online Nonintrusive Condition Monitoring and Fault Detection for Wind Turbines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei Qiao

2012-05-29

The penetration of wind power has increased greatly over the last decade in the United States and across the world. The U.S. wind power industry installed 1,118 MW of new capacity in the first quarter of 2011 alone and entered the second quarter with another 5,600 MW under construction. By 2030, wind energy is expected to provide 20% of the U.S. electricity needs. As the number of wind turbines continues to grow, the need for effective condition monitoring and fault detection (CMFD) systems becomes increasingly important [3]. Online CMFD is an effective means of not only improving the reliability, capacitymore » factor, and lifetime, but it also reduces the downtime, energy loss, and operation and maintenance (O&M) of wind turbines. The goal of this project is to develop novel online nonintrusive CMFD technologies for wind turbines. The proposed technologies use only the current measurements that have been used by the control and protection system of a wind turbine generator (WTG); no additional sensors or data acquisition devices are needed. Current signals are reliable and easily accessible from the ground without intruding on the wind turbine generators (WTGs) that are situated on high towers and installed in remote areas. Therefore, current-based CMFD techniques have great economic benefits and the potential to be adopted by the wind energy industry. Specifically, the following objectives and results have been achieved in this project: (1) Analyzed the effects of faults in a WTG on the generator currents of the WTG operating at variable rotating speed conditions from the perspective of amplitude and frequency modulations of the current measurements; (2) Developed effective amplitude and frequency demodulation methods for appropriate signal conditioning of the current measurements to improve the accuracy and reliability of wind turbine CMFD; (3) Developed a 1P-invariant power spectrum density (PSD) method for effective signature extraction of wind turbine faults with characteristic frequencies in the current or current demodulated signals, where 1P stands for the shaft rotating frequency of a WTG; (4) Developed a wavelet filter for effective signature extraction of wind turbine faults without characteristic frequencies in the current or current demodulated signals; (5) Developed an effective adaptive noise cancellation method as an alternative to the wavelet filter method for signature extraction of wind turbine faults without characteristic frequencies in the current or current demodulated signals; (6) Developed a statistical analysis-based impulse detection method for effective fault signature extraction and evaluation of WTGs based on the 1P-invariant PSD of the current or current demodulated signals; (7) Validated the proposed current-based wind turbine CMFD technologies through extensive computer simulations and experiments for small direct-drive WTGs without gearboxes; and (8) Showed, through extensive experiments for small direct-drive WTGs, that the performance of the proposed current-based wind turbine CMFD technologies is comparable to traditional vibration-based methods. The proposed technologies have been successfully applied for detection of major failures in blades, shafts, bearings, and generators of small direct-drive WTGs. The proposed technologies can be easily integrated into existing wind turbine control, protection, and monitoring systems and can be implemented remotely from the wind turbines being monitored. The proposed technologies provide an alternative to vibration-sensor-based CMFD. This will reduce the cost and hardware complexity of wind turbine CMFD systems. The proposed technologies can also be combined with vibration-sensor-based methods to improve the accuracy and reliability of wind turbine CMFD systems. When there are problems with sensors, the proposed technologies will ensure proper CMFD for the wind turbines, including their sensing systems. In conclusion, the proposed technologies offer an effective means to achieve condition-based smart maintenance for wind turbines and have a great potential to be adopted by the wind energy industry due to their almost no-cost, nonintrusive features. Although only validated for small direct-drive wind turbines without gearboxes, the proposed technologies are also applicable for CMFD of large-size wind turbines with and without gearboxes. However, additional investigations are recommended in order to apply the proposed technologies to those large-size wind turbines.« less

What Factors Influence Wind Perceptions

NASA Astrophysics Data System (ADS)

Stein, Tatiana

Over the last decade, wind power has emerged as a possible source of energy and has attracted the attention of homeowners and policy makers worldwide. Many technological hurdles have been overcome in the last few years that make this technology feasible and economical. The United States has added more wind power than any other type of electric generation in 2012. Depending on the location, wind resources have shown to have the potential to offer 20% of the nation's electricity; a single, large wind turbine has the capacity to produce enough electricity to power 350 homes. Throughout the development of wind turbines, however, energy companies have seen significant public opposition towards the tall white structures. The purpose of this research was to measure peoples' perceptions on wind turbine development throughout their growth, from proposal to existing phase. Three hypotheses were developed based on the participant's political affiliation, proximity and knowledge of wind turbines. To validate these hypotheses, participants were asked an array of questions regarding their perception on economic, environmental, and social impacts of wind turbines with an online service called Amazon Mechanical Turk. The responses were from residents living in the United States and required them to provide their zip code for subsequent analysis. The analysis from the data obtained suggests that participants are favorable towards wind turbine development and would be supportive of using the technology in their community. Political affiliation and proximity to the nearest wind turbine in any phase of development (proposal, construction, existing) were also analyzed to determine if they had an effect on a person's overall perception on wind turbines and their technology. From the analysis, political affiliation was seen to be an indirect factor to understanding favorability towards wind turbines; the more liberal you are, the more supportive you will be towards renewable energy use. Proximity, however, was found to not make a significant difference throughout the analysis, suggesting that exposure to wind turbines in any stage of development does not decrease a person's favorable perception towards wind turbines. Results also showed that those who found wind technology to be reliable, are twice as likely to have an overall positive perception and want to implement them into their communities. Socio-economic implications were also seen within the research suggesting those who believe wind turbines will benefit their local community will be more favorable towards developing them in their community.

Advanced Thermoplastic Resins for Manufacturing Wind Turbine Blades |

Science.gov Websites

Turbine Blades Advanced Thermoplastic Resins for Manufacturing Wind Turbine Blades At its Composites Arkema's Elium liquid thermoplastic resin. Photo of men working on turbine blades in a dome-shaped building composite structures of wind turbine blades. Capabilities Learn more about NREL's IACMI projects and its

Wind turbine fault detection and classification by means of image texture analysis

NASA Astrophysics Data System (ADS)

Ruiz, Magda; Mujica, Luis E.; Alférez, Santiago; Acho, Leonardo; Tutivén, Christian; Vidal, Yolanda; Rodellar, José; Pozo, Francesc

2018-07-01

The future of the wind energy industry passes through the use of larger and more flexible wind turbines in remote locations, which are increasingly offshore to benefit stronger and more uniform wind conditions. The cost of operation and maintenance of offshore wind turbines is approximately 15-35% of the total cost. Of this, 80% goes towards unplanned maintenance issues due to different faults in the wind turbine components. Thus, an auspicious way to contribute to the increasing demands and challenges is by applying low-cost advanced fault detection schemes. This work proposes a new method for detection and classification of wind turbine actuators and sensors faults in variable-speed wind turbines. For this purpose, time domain signals acquired from the operating wind turbine are represented as two-dimensional matrices to obtain grayscale digital images. Then, the image pattern recognition is processed getting texture features under a multichannel representation. In this work, four types of texture characteristics are used: statistical, wavelet, granulometric and Gabor features. Next, the most significant ones are selected using the conditional mutual criterion. Finally, the faults are detected and distinguished between them (classified) using an automatic classification tool. In particular, a 10-fold cross-validation is used to obtain a more generalized model and evaluates the classification performance. Coupled non-linear aero-hydro-servo-elastic simulations of a 5 MW offshore type wind turbine are carried out in several fault scenarios. The results show a promising methodology able to detect and classify the most common wind turbine faults.

Numerical simulations of flow fields through conventionally controlled wind turbines & wind farms

NASA Astrophysics Data System (ADS)

Emre Yilmaz, Ali; Meyers, Johan

2014-06-01

In the current study, an Actuator-Line Model (ALM) is implemented in our in-house pseudo-spectral LES solver SP-WIND, including a turbine controller. Below rated wind speed, turbines are controlled by a standard-torque-controller aiming at maximum power extraction from the wind. Above rated wind speed, the extracted power is limited by a blade pitch controller which is based on a proportional-integral type control algorithm. This model is used to perform a series of single turbine and wind farm simulations using the NREL 5MW turbine. First of all, we focus on below-rated wind speed, and investigate the effect of the farm layout on the controller calibration curves. These calibration curves are expressed in terms of nondimensional torque and rotational speed, using the mean turbine-disk velocity as reference. We show that this normalization leads to calibration curves that are independent of wind speed, but the calibration curves do depend on the farm layout, in particular for tightly spaced farms. Compared to turbines in a lone-standing set-up, turbines in a farm experience a different wind distribution over the rotor due to the farm boundary-layer interaction. We demonstrate this for fully developed wind-farm boundary layers with aligned turbine arrangements at different spacings (5D, 7D, 9D). Further we also compare calibration curves obtained from full farm simulations with calibration curves that can be obtained at a much lower cost using a minimal flow unit.

Stress analysis of composite wind turbine blade by finite element method

NASA Astrophysics Data System (ADS)

Yeh, Meng-Kao; Wang, Chen-Hsu

2017-10-01

In this study, the finite element analysis software ANSYS was used to analyze the composite wind turbine blade. The wind turbine blade model used is adopted from the 5 MW model of US National Renewable Energy Laboratory (NREL). The wind turbine blade is a sandwich structure, comprising outermost carbon fiber cloth/epoxy composites, the inner glass fiber/vinylester layers, and PVC foam core, together with stiffeners. The wind pressure is converted into the load on the blade structure. The stress distribution and deformation of wind turbine blade were obtained by considering different pitch angles and at different angular positions. The Tsai-Hill criterion was used to determine the failure of wind turbine blade. The results show that at the 0° pitch angle, the wind turbine blade is subjected to the largest combined load and therefore the stress is the largest; with the increasing pitch angle, the load gradually decreases and the stress is also smaller. The stress and displacement are the greatest when the wind blade is located at 120° angular position from its highest vertex.

Quantifying the hurricane risk to offshore wind turbines.

PubMed

Rose, Stephen; Jaramillo, Paulina; Small, Mitchell J; Grossmann, Iris; Apt, Jay

2012-02-28

The U.S. Department of Energy has estimated that if the United States is to generate 20% of its electricity from wind, over 50 GW will be required from shallow offshore turbines. Hurricanes are a potential risk to these turbines. Turbine tower buckling has been observed in typhoons, but no offshore wind turbines have yet been built in the United States. We present a probabilistic model to estimate the number of turbines that would be destroyed by hurricanes in an offshore wind farm. We apply this model to estimate the risk to offshore wind farms in four representative locations in the Atlantic and Gulf Coastal waters of the United States. In the most vulnerable areas now being actively considered by developers, nearly half the turbines in a farm are likely to be destroyed in a 20-y period. Reasonable mitigation measures--increasing the design reference wind load, ensuring that the nacelle can be turned into rapidly changing winds, and building most wind plants in the areas with lower risk--can greatly enhance the probability that offshore wind can help to meet the United States' electricity needs.

Quantifying the hurricane risk to offshore wind turbines

PubMed Central

Rose, Stephen; Jaramillo, Paulina; Small, Mitchell J.; Grossmann, Iris; Apt, Jay

2012-01-01

The U.S. Department of Energy has estimated that if the United States is to generate 20% of its electricity from wind, over 50 GW will be required from shallow offshore turbines. Hurricanes are a potential risk to these turbines. Turbine tower buckling has been observed in typhoons, but no offshore wind turbines have yet been built in the United States. We present a probabilistic model to estimate the number of turbines that would be destroyed by hurricanes in an offshore wind farm. We apply this model to estimate the risk to offshore wind farms in four representative locations in the Atlantic and Gulf Coastal waters of the United States. In the most vulnerable areas now being actively considered by developers, nearly half the turbines in a farm are likely to be destroyed in a 20-y period. Reasonable mitigation measures—increasing the design reference wind load, ensuring that the nacelle can be turned into rapidly changing winds, and building most wind plants in the areas with lower risk—can greatly enhance the probability that offshore wind can help to meet the United States’ electricity needs. PMID:22331894

Description of an 8 MW reference wind turbine

NASA Astrophysics Data System (ADS)

Desmond, Cian; Murphy, Jimmy; Blonk, Lindert; Haans, Wouter

2016-09-01

An 8 MW wind turbine is described in terms of mass distribution, dimensions, power curve, thrust curve, maximum design load and tower configuration. This turbine has been described as part of the EU FP7 project LEANWIND in order to facilitate research into logistics and naval architecture efficiencies for future offshore wind installations. The design of this 8 MW reference wind turbine has been checked and validated by the design consultancy DNV-GL. This turbine description is intended to bridge the gap between the NREL 5 MW and DTU 10 reference turbines and thus contribute to the standardisation of research and development activities in the offshore wind energy industry.

Experimental studies of Savonius wind turbines with variations sizes and fin numbers towards performance

NASA Astrophysics Data System (ADS)

Utomo, Ilham Satrio; Tjahjana, Dominicus Danardono Dwi Prija; Hadi, Syamsul

2018-02-01

The use of renewable energy in Indonesia is still low. Especially the use of wind energy. Wind turbine Savonius is one turbine that can work with low wind speed. However, Savonius wind turbines still have low efficiency. Therefore it is necessary to modify. Modifications by using the fin are expected to increase the positive drag force by creating a flow that can enter the overlap ratio of the gap. This research was conducted using experimental approach scheme. Parameters generated from the experiment include: power generator, power coefficient, torque coefficient. The experimental data will be collected by variation of fin area, horizontal finning, at wind speed 3 m/s - 4,85 m/s. Experimental results show that with the addition of fin can improve the performance of wind turbine Savonius 11%, and by using the diameter of 115 mm fin is able to provide maximum performance in wind turbine Savonius.

NREL: Renewable Resource Data Center - Wind Resource Information

Science.gov Websites

and Actual Wind Turbine Sites (September 1982) and a Wind Energy Resource Atlas of the United States Wind Resource Information Photo of five wind turbines at the Nine Canyon Wind Project. The Nine Canyon Wind Project in Benton County, Washington, includes 37 wind turbines and 48 MW of capacity

Systems Engineering Workshop 2017 | Wind | NREL

Science.gov Websites

Energy for Wind Systems Today Cost and Value of Wind Power-Implications of Wind Turbine Design, János Aaron Smith, PPI Session II: Uncertainty Impacts on Wind Turbine Design and Performance Mitigation of Wind Turbine Design Load Uncertainties, Anand Natarajan, DTU Wind Energy Uncertainty in the Wind

76 FR 6812 - Proposed Shiloh III Wind Plant Project, Solano County, CA; Proposed Habitat Conservation Plan and...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-08

... turbines and associated facilities and access roads, maintenance of the wind turbines and associated... Area). The Plan Area is adjacent to existing energy-producing facilities, most notably wind turbine.../California Independent System Operator power grid. Up to 59 wind turbines would be built in the Plan Area...

Study on the glaze ice accretion of wind turbine with various chord lengths

NASA Astrophysics Data System (ADS)

Liang, Jian; Liu, Maolian; Wang, Ruiqi; Wang, Yuhang

2018-02-01

Wind turbine icing often occurs in winter, which changes the aerodynamic characteristics of the blades and reduces the work efficiency of the wind turbine. In this paper, the glaze ice model is established for horizontal-axis wind turbine in 3-D. The model contains the grid generation, two-phase simulation, heat and mass transfer. Results show that smaller wind turbine suffers from more serious icing problem, which reflects on a larger ice thickness. Both the collision efficiency and heat transfer coefficient increase under smaller size condition.

Development of methodology for horizontal axis wind turbine dynamic analysis

NASA Technical Reports Server (NTRS)

Dugundji, J.

1982-01-01

Horizontal axis wind turbine dynamics were studied. The following findings are summarized: (1) review of the MOSTAS computer programs for dynamic analysis of horizontal axis wind turbines; (2) review of various analysis methods for rotating systems with periodic coefficients; (3) review of structural dynamics analysis tools for large wind turbine; (4) experiments for yaw characteristics of a rotating rotor; (5) development of a finite element model for rotors; (6) development of simple models for aeroelastics; and (7) development of simple models for stability and response of wind turbines on flexible towers.

United States Supports Distributed Wind Technology Improvements; NREL (National Renewable Energy Laboratory)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinclair, Karin

2015-06-15

This presentation provides information on the activities conducted through the Competitiveness Improvement Project (CIP), initiated in 2012 by the U.S. Department of Energy (DOE) and executed through the National Renewable Energy Laboratory (NREL) to support the distributed wind industry. The CIP provides research and development funding and technical support to improve distributed wind turbine technology and increase the competitiveness of U.S. small and midsize wind turbine manufacturers. Through this project, DOE/NREL assists U.S. manufacturers to lower the levelized cost of energy of wind turbines through component improvements, manufacturing process upgrades, and turbine testing. Ultimately, this support is expected to leadmore » to turbine certification through testing to industry-recognized wind turbine performance and safety standards.« less

Wind Turbine Wake-Redirection Control at the Fishermen's Atlantic City Windfarm: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Churchfield, M.; Fleming, P.; Bulder, B.

2015-05-06

In this paper, we will present our work towards designing a control strategy to mitigate wind turbine wake effects by redirecting the wakes, specifically applied to the Fishermen’s Atlantic City Windfarm (FACW), proposed for deployment off the shore of Atlantic City, New Jersey. As wind turbines extract energy from the air, they create low-speed wakes that extend behind them. Full wake recovery Full wake recovery to the undisturbed wind speed takes a significant distance. In a wind energy plant the wakes of upstream turbines may travel downstream to the next row of turbines, effectively subjecting them to lower wind speeds,more » meaning these waked turbines will produce less power.« less

Wind Turbine With Concentric Ducts

NASA Technical Reports Server (NTRS)

Muhonen, A. J.

1983-01-01

Wind Turbine device is relatively compact and efficient. Converging inner and outer ducts increase pressure difference across blades of wind turbine. Turbine shaft drives alternator housed inside exit cone. Suitable for installation on such existing structures as water towers, barns, houses, and commercial buildings.

Contingency power for a small turboshaft engine by using water injection into turbine cooling air

NASA Technical Reports Server (NTRS)

Biesiadny, Thomas J.; Klann, Gary A.

1992-01-01

Because of one-engine-inoperative (OEI) requirements, together with hot-gas reingestion and hot-day, high-altitude take-off situations, power augmentation for multiengine rotorcraft has always been of critical interest. However, power augmentation by using overtemperature at the turbine inlet will shorten turbine life unless a method of limiting thermal and mechanical stress is found. A possible solution involves allowing the turbine inlet temperature to rise to augment power while injecting water into the turbine cooling air to limit hot-section metal temperatures. An experimental water injection device was installed in an engine and successfully tested. Although concern for unprotected subcomponents in the engine hot section prevented demonstration of the technique's maximum potential, it was still possible to demonstrate increases in power while maintaining nearly constant turbine rotor blade temperature.

National Wind Technology Center | NREL

Science.gov Websites

. Wind Energy Research Wind turbine blade Wind energy research at the NWTC allows for validation and verification of large and small components and wind turbine systems. Photo by Dennis Schroeder / NREL 40935 Wind energy research at the NWTC has pioneered wind turbine components, systems, and modeling methods

Simulating Turbulent Wind Fields for Offshore Turbines in Hurricane-Prone Regions (Poster)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Y.; Damiani, R.; Musial, W.

Extreme wind load cases are one of the most important external conditions in the design of offshore wind turbines in hurricane prone regions. Furthermore, in these areas, the increase in load with storm return-period is higher than in extra-tropical regions. However, current standards have limited information on the appropriate models to simulate wind loads from hurricanes. This study investigates turbulent wind models for load analysis of offshore wind turbines subjected to hurricane conditions. Suggested extreme wind models in IEC 61400-3 and API/ABS (a widely-used standard in oil and gas industry) are investigated. The present study further examines the wind turbinemore » response subjected to Hurricane wind loads. Three-dimensional wind simulator, TurbSim, is modified to include the API wind model. Wind fields simulated using IEC and API wind models are used for an offshore wind turbine model established in FAST to calculate turbine loads and response.« less

Optimization of Wind Turbine Airfoils/Blades and Wind Farm Layouts

NASA Astrophysics Data System (ADS)

Chen, Xiaomin

Shape optimization is widely used in the design of wind turbine blades. In this dissertation, a numerical optimization method called Genetic Algorithm (GA) is applied to address the shape optimization of wind turbine airfoils and blades. In recent years, the airfoil sections with blunt trailing edge (called flatback airfoils) have been proposed for the inboard regions of large wind-turbine blades because they provide several structural and aerodynamic performance advantages. The FX, DU and NACA 64 series airfoils are thick airfoils widely used for wind turbine blade application. They have several advantages in meeting the intrinsic requirements for wind turbines in terms of design point, off-design capabilities and structural properties. This research employ both single- and multi-objective genetic algorithms (SOGA and MOGA) for shape optimization of Flatback, FX, DU and NACA 64 series airfoils to achieve maximum lift and/or maximum lift to drag ratio. The commercially available software FLUENT is employed for calculation of the flow field using the Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with a two-equation Shear Stress Transport (SST) turbulence model and a three equation k-kl-o turbulence model. The optimization methodology is validated by an optimization study of subsonic and transonic airfoils (NACA0012 and RAE 2822 airfoils). In this dissertation, we employ DU 91-W2-250, FX 66-S196-V1, NACA 64421, and Flat-back series of airfoils (FB-3500-0050, FB-3500-0875, and FB-3500-1750) and compare their performance with S809 airfoil used in NREL Phase II and III wind turbines; the lift and drag coefficient data for these airfoils sections are available. The output power of the turbine is calculated using these airfoil section blades for a given B and lambda and is compared with the original NREL Phase II and Phase III turbines using S809 airfoil section. It is shown that by a suitable choice of airfoil section of HAWT blade, the power generated by the turbine can be significantly increased. Parametric studies are also conducted by varying the turbine diameter. In addition, a simplified dynamic inflow model is integrated into the BEM theory. It is shown that the improved BEM theory has superior performance in capturing the instantaneous behavior of wind turbines due to the existence of wind turbine wake or temporal variations in wind velocity. The dissertation also considers the Wind Farm layout optimization problem using a genetic algorithm. Both the Horizontal --Axis Wind Turbines (HAWT) and Vertical-Axis Wind Turbines (VAWT) are considered. The goal of the optimization problem is to optimally position the turbines within the wind farm such that the wake effects are minimized and the power production is maximized. The reasonably accurate modeling of the turbine wake is critical in determination of the optimal layout of the turbines and the power generated. For HAWT, two wake models are considered; both are found to give similar answers. For VAWT, a very simple wake model is employed. Finally, some preliminary investigation of shape optimization of 3D wind turbine blades at low Reynolds numbers is conducted. The optimization employs a 3D straight untapered wind turbine blade with cross section of NACA 0012 airfoils as the geometry of baseline blade. The optimization objective is to achieve maximum Cl/Cd as well as maximum Cl. The multi-objective genetic algorithm is employed together with the commercially available software FLUENT for calculation of the flow field using the Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with a one-equation Sparlart-Allmaras turbulence model. The results show excellent performance of the optimized wind turbine blade and indicate the feasibility of optimization on real wind turbine blades with more complex shapes in the future. (Abstract shortened by UMI.)

Numerical investigations on the aerodynamic performance of wind turbine: Downwind versus upwind configuration

NASA Astrophysics Data System (ADS)

Zhou, Hu; Wan, Decheng

2015-03-01

Although the upwind configuration is more popular in the field of wind energy, the downwind one is a promising type for the offshore wind energy due to its special advantages. Different configurations have different aerodynamic performance and it is important to predict the performance of both downwind and upwind configurations accurately for designing and developing more reliable wind turbines. In this paper, a numerical investigation on the aerodynamic performance of National Renewable Energy Laboratory (NREL) phase VI wind turbine in downwind and upwind configurations is presented. The open source toolbox OpenFOAM coupled with arbitrary mesh interface (AMI) method is applied to tackle rotating problems of wind turbines. Two 3D numerical models of NREL phase VI wind turbine with downwind and upwind configurations under four typical working conditions of incoming wind velocities are set up for the study of different unsteady characteristics of the downwind and upwind configurations, respectively. Numerical results of wake vortex structure, time histories of thrust, pressure distribution on the blade and limiting streamlines which can be used to identify points of separation in a 3D flow are presented. It can be concluded that thrust reduction due to blade-tower interaction is small for upwind wind turbines but relatively large for downwind wind turbines and attention should be paid to the vibration at a certain frequency induced by the cyclic reduction for both configurations. The results and conclusions are helpful to analyze the different aerodynamic performance of wind turbines between downwind and upwind configurations, providing useful references for practical design of wind turbine.

Risk analysis of maintenance ship collisions with offshore wind turbines

NASA Astrophysics Data System (ADS)

Presencia, Carla E.; Shafiee, Mahmood

2018-07-01

A large number of offshore wind farms are planned to be built in remote deep-sea areas over the next five years. Though offshore wind sites are often located away from commercial ship traffic, the increased demand for repair or replacement services leads to high traffic densities of "maintenance ships". To date, the risk analysis of collision between maintenance ship vessels and offshore wind turbines has received very little attention. In this paper, we propose a methodology to evaluate and prioritise the collision risks associated with various kinds of ships used for carrying out maintenance tasks on different subassemblies of wind turbines in an offshore wind farm. It is also studied how the risks of ship collision with wind turbines are distributed between two main types of maintenance tasks, namely corrective and preventative. The proposed model is tested on an offshore wind turbine with seventeen components requiring five kinds of ships to perform the maintenance tasks. Our results indicate that collision risks are mostly associated with maintenance of few components of the wind turbine and in particular, those undergoing a corrective maintenance (replacement). Finally, several mitigation strategies are introduced to minimise the risk of maintenance ship collisions with offshore wind turbines.

Measurements of Heat Flux Differences Within a Large Wind Farm During the 2013 Crop/Wind-Energy Experiment (CWEX-13)

NASA Astrophysics Data System (ADS)

Rajewski, D. A.

2015-12-01

Wind farms are an important resource for electrical generation in the Central U.S., however with each installation there are many poorly documented interactions with the local and surrounding environment. The impact of wind farms on surface microclimate is largely understood conceptually using numerical or wind tunnel models or ex situ satellite-detected changes. Measurements suitable for calibration of numerical simulations are few and of limited applicability but are urgently needed to improve parameterization of wind farm aerodynamics influenced by the diurnal evolution of the boundary layer. Among large eddy simulations of wind farm wakes in thermally stable stratification, there are discrepancies on the influence of turbine-induced mixing on the surface heat flux. We provide measurements from seven surface flux stations, vertical profiling LiDARs located upwind and downwind of turbines, and SCADA measurements from turbines during the 2013 Crop Wind Energy Experiment (CWEX-13) as the best evidence for the variability of turbine induced heat flux within a large wind farm. Examination of ambient conditions (wind direction, wind veer, and thermal stratification) and on turbine operation factors (hub-height wind speed, normalized power) reveal conditions that lead to the largest modification of heat flux. Our results demonstrate the highest flux change from the reference station to be where the leading few lines of turbines influence the surface. Under stably stratified conditions turbine-scale turbulence is highly efficient at bringing warmer air aloft to the surface, leading to an increase in downward heat flux. Conversely we see that the combination of wakes from several lines of turbines reduces the flux contrast from the reference station. In this regime of deep wind-farm flow, wake turbulence is similar in scale and intensity to the reference conditions. These analysis tools can be extended to other turbine SCADA and microclimate variables (e.g. temperature) to improve basic understanding of turbine-turbine and total wind farm wake interactions. Forthcoming tall-tower measurements will provide additional opportunities for comparison of simulated wind and thermal profiles in non-wake, and waked flow conditions.

Optimizing Wind Power Generation while Minimizing Wildlife Impacts in an Urban Area

PubMed Central

Bohrer, Gil; Zhu, Kunpeng; Jones, Robert L.; Curtis, Peter S.

2013-01-01

The location of a wind turbine is critical to its power output, which is strongly affected by the local wind field. Turbine operators typically seek locations with the best wind at the lowest level above ground since turbine height affects installation costs. In many urban applications, such as small-scale turbines owned by local communities or organizations, turbine placement is challenging because of limited available space and because the turbine often must be added without removing existing infrastructure, including buildings and trees. The need to minimize turbine hazard to wildlife compounds the challenge. We used an exclusion zone approach for turbine-placement optimization that incorporates spatially detailed maps of wind distribution and wildlife densities with power output predictions for the Ohio State University campus. We processed public GIS records and airborne lidar point-cloud data to develop a 3D map of all campus buildings and trees. High resolution large-eddy simulations and long-term wind climatology were combined to provide land-surface-affected 3D wind fields and the corresponding wind-power generation potential. This power prediction map was then combined with bird survey data. Our assessment predicts that exclusion of areas where bird numbers are highest will have modest effects on the availability of locations for power generation. The exclusion zone approach allows the incorporation of wildlife hazard in wind turbine siting and power output considerations in complex urban environments even when the quantitative interaction between wildlife behavior and turbine activity is unknown. PMID:23409117

Optimizing wind power generation while minimizing wildlife impacts in an urban area.

PubMed

Bohrer, Gil; Zhu, Kunpeng; Jones, Robert L; Curtis, Peter S

2013-01-01

The location of a wind turbine is critical to its power output, which is strongly affected by the local wind field. Turbine operators typically seek locations with the best wind at the lowest level above ground since turbine height affects installation costs. In many urban applications, such as small-scale turbines owned by local communities or organizations, turbine placement is challenging because of limited available space and because the turbine often must be added without removing existing infrastructure, including buildings and trees. The need to minimize turbine hazard to wildlife compounds the challenge. We used an exclusion zone approach for turbine-placement optimization that incorporates spatially detailed maps of wind distribution and wildlife densities with power output predictions for the Ohio State University campus. We processed public GIS records and airborne lidar point-cloud data to develop a 3D map of all campus buildings and trees. High resolution large-eddy simulations and long-term wind climatology were combined to provide land-surface-affected 3D wind fields and the corresponding wind-power generation potential. This power prediction map was then combined with bird survey data. Our assessment predicts that exclusion of areas where bird numbers are highest will have modest effects on the availability of locations for power generation. The exclusion zone approach allows the incorporation of wildlife hazard in wind turbine siting and power output considerations in complex urban environments even when the quantitative interaction between wildlife behavior and turbine activity is unknown.

Dynamic Federalism and Wind Farm Siting

DTIC Science & Technology

2014-05-18

drawbacks, however. Among these, the mechanical and electromagnetic properties of wind turbines pose significant hazards and complications to U.S...have drawbacks, however. Among these, the mechanical and electromagnetic properties of wind turbines pose significant hazards and complications to...benefits. Wind energy conversion systems are no exception. Wind power systems use elevated turbines to capture mechanical energy from the wind

@NWTC Newsletter: Fall 2013 | Wind | NREL

Science.gov Websites

Assessment of the U.S. Wind Industry in 2012 NREL Identifies Investments for Wind Turbine Drivetrain , medium-speed, medium-voltage wind turbine drivetrain design. Tapping into unparalleled expertise, the The drivetrain of a wind turbine converts the power of the wind into electrical energy. Now

Distributed Wind Research | Wind | NREL

Science.gov Websites

evaluation, and improve wind turbine and wind power plant performance. A photo of a snowy road leading to a single wind turbine surrounded by snow-covered pine trees against blue sky. Capabilities NREL's power plant and small wind turbine development. Algorithms and programs exist for simulating, designing

A Comprehensive Structural Study of Offshore Wind Turbine Foundation and Non-Model Based Damage Detection using Effective Mass with Application to Small Components/ Cables and a Truss Wind Turbine Tower

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Scott A.

This research has two areas of focus. The first area is to investigate offshore wind turbine (OWT) designs, for use in the Maryland offshore wind area (MOWA), using intensive modeling techniques. The second focus area is to investigate a way to detect damage in wind turbine towers and small electrical components.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sherwood, Larry

The Small Wind Certification Council (SWCC) created a successful accredited certification program for small and medium wind turbines using the funding from this grant. SWCC certifies small turbines (200 square meters of swept area or less) to the American Wind Energy Association (AWEA) Small Wind Turbine Performance and Safety Standard (AWEA Standard 9.1 – 2009). SWCC also certifies medium wind turbines to the International Electrical Commission (IEC) Power Performance Standard (IEC 61400-12-1) and Acoustic Performance Standard (IEC 61400-11).

How the factoid of wind turbines causing 'vibroacoustic disease' came to be 'irrefutably demonstrated'.

PubMed

Chapman, Simon; St George, Alexis

2013-06-01

In recent years, claims have proliferated in cyberspace that wind turbines cause a large variety of symptoms and diseases. One of these, "vibroacoustic disease" (VAD) is frequently mentioned. The aim of this study is to examine the quality of the evidence on how VAD came to be associated with wind turbine exposure by wind farm opponents. Searches of the web (Google advanced) and major research databases for papers on VAD and wind turbines. Self-citation analysis of research papers on VAD. Google returned 24,700 hits for VAD and wind turbines. Thirty-five research papers on VAD were found, none reporting any association between VAD and wind turbines. Of the 35 papers, 34 had a first author from a single Portuguese research group. Seventy-four per cent of citations to these papers were self-citations by the group. Median self-citation rates in science are around 7%. Two unpublished case reports presented at conferences were found asserting that VAD was "irrefutably demonstrated" to be caused by wind turbines. The quality of these reports was abject. VAD has received virtually no scientific recognition beyond the group who coined and promoted the concept. There is no evidence of even rudimentary quality that vibroacoustic disease is associated with or caused by wind turbines. The claim that wind turbines cause VAD is a factoid that has gone 'viral' in cyberspace and may be contributing to nocebo effects among those living near turbines. © 2013 The Authors. ANZJPH © 2013 Public Health Association of Australia.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jie; Jain, Rishabh; Hodge, Bri-Mathias

A data-driven methodology is developed to analyze how ambient and wake turbulence affect the power generation of wind turbine(s). Using supervisory control and data acquisition (SCADA) data from a wind plant, we select two sets of wind velocity and power data for turbines on the edge of the plant that resemble (i) an out-of-wake scenario and (ii) an in-wake scenario. For each set of data, two surrogate models are developed to represent the turbine(s) power generation as a function of (i) the wind speed and (ii) the wind speed and turbulence intensity. Three types of uncertainties in turbine(s) power generationmore » are investigated: (i) the uncertainty in power generation with respect to the reported power curve; (ii) the uncertainty in power generation with respect to the estimated power response that accounts for only mean wind speed; and (iii) the uncertainty in power generation with respect to the estimated power response that accounts for both mean wind speed and turbulence intensity. Results show that (i) the turbine(s) generally produce more power under the in-wake scenario than under the out-of-wake scenario with the same wind speed; and (ii) there is relatively more uncertainty in the power generation under the in-wake scenario than under the out-of-wake scenario.« less

Analyzing Effects of Turbulence on Power Generation Using Wind Plant Monitoring Data: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, J.; Chowdhury, S.; Hodge, B. M.

2014-01-01

In this paper, a methodology is developed to analyze how ambient and wake turbulence affects the power generation of a single wind turbine within an array of turbines. Using monitoring data from a wind power plant, we selected two sets of wind and power data for turbines on the edge of the wind plant that resemble (i) an out-of-wake scenario (i.e., when the turbine directly faces incoming winds) and (ii) an in-wake scenario (i.e., when the turbine is under the wake of other turbines). For each set of data, two surrogate models were then developed to represent the turbine powermore » generation (i) as a function of the wind speed; and (ii) as a function of the wind speed and turbulence intensity. Support vector regression was adopted for the development of the surrogate models. Three types of uncertainties in the turbine power generation were also investigated: (i) the uncertainty in power generation with respect to the published/reported power curve, (ii) the uncertainty in power generation with respect to the estimated power response that accounts for only mean wind speed; and (iii) the uncertainty in power generation with respect to the estimated power response that accounts for both mean wind speed and turbulence intensity. Results show that (i) under the same wind conditions, the turbine generates different power between the in-wake and out-of-wake scenarios, (ii) a turbine generally produces more power under the in-wake scenario than under the out-of-wake scenario, (iii) the power generation is sensitive to turbulence intensity even when the wind speed is greater than the turbine rated speed, and (iv) there is relatively more uncertainty in the power generation under the in-wake scenario than under the out-of-wake scenario.« less

3D-PTV around Operational Wind Turbines

NASA Astrophysics Data System (ADS)

Brownstein, Ian; Dabiri, John

2016-11-01

Laboratory studies and numerical simulations of wind turbines are typically constrained in how they can inform operational turbine behavior. Laboratory experiments are usually unable to match both pertinent parameters of full-scale wind turbines, the Reynolds number (Re) and tip speed ratio, using scaled-down models. Additionally, numerical simulations of the flow around wind turbines are constrained by the large domain size and high Re that need to be simulated. When these simulations are preformed, turbine geometry is typically simplified resulting in flow structures near the rotor not being well resolved. In order to bypass these limitations, a quantitative flow visualization method was developed to take in situ measurements of the flow around wind turbines at the Field Laboratory for Optimized Wind Energy (FLOWE) in Lancaster, CA. The apparatus constructed was able to seed an approximately 9m x 9m x 5m volume in the wake of the turbine using artificial snow. Quantitative measurements were obtained by tracking the evolution of the artificial snow using a four camera setup. The methodology for calibrating and collecting data, as well as preliminary results detailing the flow around a 2kW vertical-axis wind turbine (VAWT), will be presented.

Mod-1 Wind Turbine at Boone, North Carolina

NASA Image and Video Library

1979-06-21

A Mod-1 2000-kilowatt wind turbine designed by National Aeronautics and Space Administration (NASA) Lewis Research Center and constructed in Boone, North Carolina. The wind turbine program was a joint program between NASA and the Energy Research and Development Administration (ERDA) during the 1970s to develop less expensive forms of energy. NASA Lewis was assigned the responsibility of developing large horizontal-axis wind turbines. The program included a series of increasingly powerful wind turbines, designated: Mod-0A, Mod-1, WTS-4, and Mod-5. The program’s first device was a Mod-0 100-kilowatt wind turbine test bed at NASA’s Plum Brook Station. There were four Mod-0A 200-kilowatt turbines built in New Mexico, Hawaii, Puerto Rico, and Rhode Island. The 2000-kilowatt wind turbine in North Carolina, seen here, was the only Mod-1 machine constructed. The two-bladed, 200-foot diameter device was built in May 1979 and began operation that September. The Mod-1 turbine performed exceedingly well and was fully integrated into the local power grid. NASA researchers also used the North Carolina device to study its effect on noise and television transmission.

NREL and Sandia National Laboratories to Sharpen Wind Farm Turbine Controls

Science.gov Websites

| News | NREL NREL and Sandia National Laboratories to Sharpen Wind Farm Turbine Controls NREL and Sandia National Laboratories to Sharpen Wind Farm Turbine Controls April 1, 2016 Researchers at wind turbine modeling. The NREL controls team have been evaluating their control theory in simulations

77 FR 2999 - Notice of Availability of the Draft Environmental Impact Statement and Notice of Segregation for...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-20

... Resource Management Plan. The proposed wind turbines would be up to 262-feet-tall from the ground to the... to 415 feet. In addition to the wind turbines, the proposed project would require the construction of... the Draft EIS--an 87 wind turbine layout, a 96 wind turbine alternative, and a no-action alternative...

Chapter 15: Reliability of Wind Turbines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheng, Shuangwen; O'Connor, Ryan

The global wind industry has witnessed exciting developments in recent years. The future will be even brighter with further reductions in capital and operation and maintenance costs, which can be accomplished with improved turbine reliability, especially when turbines are installed offshore. One opportunity for the industry to improve wind turbine reliability is through the exploration of reliability engineering life data analysis based on readily available data or maintenance records collected at typical wind plants. If adopted and conducted appropriately, these analyses can quickly save operation and maintenance costs in a potentially impactful manner. This chapter discusses wind turbine reliability bymore » highlighting the methodology of reliability engineering life data analysis. It first briefly discusses fundamentals for wind turbine reliability and the current industry status. Then, the reliability engineering method for life analysis, including data collection, model development, and forecasting, is presented in detail and illustrated through two case studies. The chapter concludes with some remarks on potential opportunities to improve wind turbine reliability. An owner and operator's perspective is taken and mechanical components are used to exemplify the potential benefits of reliability engineering analysis to improve wind turbine reliability and availability.« less

Offshore wind turbine foundation monitoring, extrapolating fatigue measurements from fleet leaders to the entire wind farm

NASA Astrophysics Data System (ADS)

Weijtens, Wout; Noppe, Nymfa; Verbelen, Tim; Iliopoulos, Alexandros; Devriendt, Christof

2016-09-01

The present contribution is part of the ongoing development of a fatigue assessment strategy driven purely on in-situ measurements on operational wind turbines. The primary objective is to estimate the remaining life time of existing wind farms and individual turbines by instrumenting part of the farm with a load monitoring setup. This load monitoring setup allows to measure interface loads and local stress histories. This contribution will briefly discuss how these load measurements can be translated into fatigue assessment of the instrumented turbine. However, due to different conditions at the wind farm, such as turbulence, differences in water depth and foundation design this turbine will not be fully representable for all turbines in the farm. In this paper we will use the load measurements on two offshore wind turbines in the Northwind offshore wind farm to discuss fatigue progression in an operational wind farm. By calculating the damage equivalent loads on the two turbines the fatigue progression is quantified for every 10 minute interval and can be analyzed against turbulence and site conditions. In future work these results will be used to predict the fatigue life progression in the entire farm.

Collected Papers on Wind Turbine Technology

NASA Technical Reports Server (NTRS)

Spera, David A. (Editor)

1995-01-01

R and D projects on electricity generating wind turbines were conducted at the NASA Lewis Research Center from 1973 to 1988. Most projects were sponsored by the U.S. Department of Energy (DOE), a major element of its Federal Wind Energy Program. Another large wind turbine project was by the Bureau of Reclamation of the U.S. Department of Interior (DOI). From 1988 to 1995, NASA wind energy activities have been directed toward the transfer of technology to commercial and academic organizations. As part of these technology transfer activities, previously unpublished manuscripts have been assembled and presented here to share the wind turbine research results with the wind energy community. A variety of wind turbine technology topics are discussed: Wind and wake models; Airfoil properties; Structural analysis and testing; Control systems; Variable speed generators; and acoustic noise. Experimental and theoretical results are discussed.

Hardware-in-the-Loop Testing of Utility-Scale Wind Turbine Generators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schkoda, Ryan; Fox, Curtiss; Hadidi, Ramtin

2016-01-26

Historically, wind turbine prototypes were tested in the field, which was--and continues to be--a slow and expensive process. As a result, wind turbine dynamometer facilities were developed to provide a more cost-effective alternative to field testing. New turbine designs were tested and the design models were validated using dynamometers to drive the turbines in a controlled environment. Over the years, both wind turbine dynamometer testing and computer technology have matured and improved, and the two are now being joined to provide hardware-in-the-loop (HIL) testing. This type of testing uses a computer to simulate the items that are missing from amore » dynamometer test, such as grid stiffness, voltage, frequency, rotor, and hub. Furthermore, wind input and changing electric grid conditions can now be simulated in real time. This recent advance has greatly increased the utility of dynamometer testing for the development of wind turbine systems.« less

Profitability Analysis of Residential Wind Turbines with Battery Energy Storage

NASA Astrophysics Data System (ADS)

She, Ying; Erdem, Ergin; Shi, Jing

Residential wind turbines are often accompanied by an energy storage system for the off-the-grid users, instead of the on-the-grid users, to reduce the risk of black-out. In this paper, we argue that residential wind turbines with battery energy storage could actually be beneficial to the on-the-grid users as well in terms of monetary gain from differential pricing for buying electricity from the grid and the ability to sell electricity back to the grid. We develop a mixed-integer linear programming model to maximize the profit of a residential wind turbine system while meeting the daily household electricity consumption. A case study is designed to investigate the effects of differential pricing schemes and sell-back schemes on the economic output of a 2-kW wind turbine with lithium battery storage. Overall, based on the current settings in California, a residential wind turbine with battery storage carries more economical benefits than the wind turbine alone.

Performance test of a low cost roof-mounted wind turbine

NASA Astrophysics Data System (ADS)

Figueroa-Espinoza, Bernardo; Quintal, Roberto; Gou, Clément; Aguilar, Alicia

2013-11-01

A low cost wind turbine was implemented based on the ideas put forward by Hugh Piggot in his book ``A wind turbine recipe book,'' where such device is developed using materials and manufacturing processes available (as much as possible) in developing countries or isolated communities. The wind turbine is to be mounted on a two stories building roof in a coastal zone of Mexico. The velocity profiles and turbulence intensities for typical wind conditions on top of the building roof were analyzed using numerical simulations (RANS) in order to locate the turbine hub above any recirculation and near the maximum average speed. The coefficient of performance is going to be evaluated experimentally by measuring the electrical power generation and wind characteristics that drive the wind turbine on the field. These experimental results will be applied on the improvement of the wind turbine design, as well as the validation of a numerical simulation model that couples the wind characteristics obtained through CFD with the Blade Element Method (BEM) and an electro-mechanical model of the turbine-shaft-generator ensemble. Special thanks to the Coordinación de Investigación Científica of the Universidad Michoacana de San Nicolás de Hidalgo for their support.

Determination of the number of Vertical Axis Wind Turbine blades based on power spectrum

NASA Astrophysics Data System (ADS)

Fedak, Waldemar; Anweiler, Stanisław; Gancarski, Wojciech; Ulbrich, Roman

2017-10-01

Technology of wind exploitation has been applied widely all over the world and has already reached the level in which manufacturers want to maximize the yield with the minimum investment outlays. The main objective of this paper is the determination of the optimal number of blades in the Cup-Bladed Vertical Axis Wind Turbine. Optimizing the size of the Vertical Axis Wind Turbine allows the reduction of costs. The maximum power of the rotor is selected as the performance target. The optimum number of Vertical Axis Wind Turbine blades evaluation is based on analysis of a single blade simulation and its superposition for the whole rotor. The simulation of working blade was done in MatLab environment. Power spectrum graphs were prepared and compared throughout superposition of individual blades in the Vertical Axis Wind Turbine rotor. The major result of this research is the Vertical Axis Wind Turbine power characteristic. On the basis of the analysis of the power spectra, optimum number of the blades was specified for the analysed rotor. Power spectrum analysis of wind turbine enabled the specification of the optimal number of blades, and can be used regarding investment outlays and power output of the Vertical Axis Wind Turbine.

On the biological plausibility of Wind Turbine Syndrome.

PubMed

Harrison, Robert V

2015-01-01

An emerging environmental health issue relates to potential ill-effects of wind turbine noise. There have been numerous suggestions that the low-frequency acoustic components in wind turbine signals can cause symptoms associated with vestibular system disorders, namely vertigo, nausea, and nystagmus. This constellation of symptoms has been labeled as Wind Turbine Syndrome, and has been identified in case studies of individuals living close to wind farms. This review discusses whether it is biologically plausible for the turbine noise to stimulate the vestibular parts of the inner ear and, by extension, cause Wind Turbine Syndrome. We consider the sound levels that can activate the semicircular canals or otolith end organs in normal subjects, as well as in those with preexisting conditions known to lower vestibular threshold to sound stimulation.

Large wind turbine generators. [NASA program status and potential costs

NASA Technical Reports Server (NTRS)

Thomas, R. L.; Donovon, R. M.

1978-01-01

The large wind turbine portion of the Federal Wind Energy Program consists of two major project efforts: (1) the Mod-0 test bed project for supporting research technology, and (2) the large experimental wind turbines for electric utility applications. The Mod-0 has met its primary objective of providing the entire wind energy program with early operations and performance data. The large experimental wind turbines to be tested in utility applications include three of the Mod-0A (200 kW) type, one Mod-1 (2000 kW), and possibly several of the Mod-2 (2500 kW) designs. This paper presents a description of these wind turbine systems, their programmatic status, and a summary of their potential costs.

Investigation of wind turbine effects on Evapotranspiration using surface energy balance model based on satellite-derived data

NASA Astrophysics Data System (ADS)

hassanpour Adeh, E.; Higgins, C. W.

2014-12-01

Wind turbines have been introduced as an energy source that does not require a large expenditure of water. However, recent simulation results indicate that wind turbines increase evaporation rates from the nearby land. In this research the effect of wind energy on irrigated agriculture is determined using a Surface Energy Balance Algorithm (SEBAL) on Landsat data spanning a 30 year interval. The analysis allows the characterization of evapotranspiration (ET) before and after wind turbine installations. The time history of ET from Landsat data will be presented for several major wind farms across the US. These data will be used to determine the impact on water demand due to presence of wind turbines.

Wind Tunnel Investigation of the Near-wake Flow Dynamics of a Horizontal Axis Wind Turbine

NASA Astrophysics Data System (ADS)

Hashemi-Tari, P.; Siddiqui, K.; Refan, M.; Hangan, H.

2014-06-01

Experiments conducted in a large wind tunnel set-up investigate the 3D flow dynamics within the near-wake region of a horizontal axis wind turbine. Particle Image Velocimetry (PIV) measurements quantify the mean and turbulent components of the flow field. Measurements are performed in multiple adjacent horizontal planes in order to cover the area behind the rotor in a large radial interval, at several locations downstream of the rotor. The measurements were phase-locked in order to facilitate the re-construction of the threedimensional flow field. The mean velocity and turbulence characteristics clearly correlate with the near-wake vortex dynamics and in particular with the helical structure of the flow, formed immediately behind the turbine rotor. Due to the tip and root vortices, the mean and turbulent characteristics of the flow are highly dependent on the azimuth angle in regions close to the rotor and close to the blade tip and root. Further from the rotor, the characteristics of the flow become phase independent. This can be attributed to the breakdown of the vortical structure of the flow, resulting from the turbulent diffusion. In general, the highest levels of turbulence are observed in shear layer around the tip of the blades, which decrease rapidly downstream. The shear zone grows in the radial direction as the wake moves axially, resulting in velocity recovery toward the centre of the rotor due to momentum transport.

Global Energy and Aviation Concerns

NASA Technical Reports Server (NTRS)

Hendricks, Robert C.; Daggett, Dave; Anast, Peter; Lowery, Nathan

2006-01-01

Renewable energy sources are usually diffuse and require large facilities. Biofuels work better, are more economical to produce for ground transportation, but sharply increase competition for food croplands. Noble laureate Richard Smalley (deceased-2005) conceptual 20 TWe power generation covers hundreds x hundreds of miles. Combined with Fuller s superconducting power grid system would enable renewable planetary energy. A solar-wind project in Australia will have a 7km diameter collector interfacing with a 1 km tower to extract 200 MW from wind turbines mounted at the base. GE Energy s 3.5MW Wind Turbine is large and placing this in perspective, it is as if one were rotating a Boeing 747-200; the blade diameter is that large. Wind turbines are rapidly gaining popularity in Europe and photovoltaic (PV) is expected to also expand rapidly. It becomes clear that we need (and still have time) to develop new sources of energy. Hf 178 bombarded by X-rays produces Gamma-rays for heating. The reaction stops when the X-rays stop; the half life is about 30 years and seems manageable vs 30 000 years. Water splitting needs to be perused as do ultra fast ultra intense laser applications in terms of fusion and new materials developments including new ways to strip and re-bind hydrogen into fuels. New methods and tools for development are being found in quantum mechanical applications to macro-systems and need to be developed into a set of new tool boxes for development of these new energy sources.

Response to noise from modern wind farms in The Netherlands.

PubMed

Pedersen, Eja; van den Berg, Frits; Bakker, Roel; Bouma, Jelte

2009-08-01

The increasing number and size of wind farms call for more data on human response to wind turbine noise, so that a generalized dose-response relationship can be modeled and possible adverse health effects avoided. This paper reports the results of a 2007 field study in The Netherlands with 725 respondents. A dose-response relationship between calculated A-weighted sound pressure levels and reported perception and annoyance was found. Wind turbine noise was more annoying than transportation noise or industrial noise at comparable levels, possibly due to specific sound properties such as a "swishing" quality, temporal variability, and lack of nighttime abatement. High turbine visibility enhances negative response, and having wind turbines visible from the dwelling significantly increased the risk of annoyance. Annoyance was strongly correlated with a negative attitude toward the visual impact of wind turbines on the landscape. The study further demonstrates that people who benefit economically from wind turbines have a significantly decreased risk of annoyance, despite exposure to similar sound levels. Response to wind turbine noise was similar to that found in Sweden so the dose-response relationship should be generalizable.

Comparison of three methods for wind turbine capacity factor estimation.

PubMed

Ditkovich, Y; Kuperman, A

2014-01-01

Three approaches to calculating capacity factor of fixed speed wind turbines are reviewed and compared using a case study. The first "quasiexact" approach utilizes discrete wind raw data (in the histogram form) and manufacturer-provided turbine power curve (also in discrete form) to numerically calculate the capacity factor. On the other hand, the second "analytic" approach employs a continuous probability distribution function, fitted to the wind data as well as continuous turbine power curve, resulting from double polynomial fitting of manufacturer-provided power curve data. The latter approach, while being an approximation, can be solved analytically thus providing a valuable insight into aspects, affecting the capacity factor. Moreover, several other merits of wind turbine performance may be derived based on the analytical approach. The third "approximate" approach, valid in case of Rayleigh winds only, employs a nonlinear approximation of the capacity factor versus average wind speed curve, only requiring rated power and rotor diameter of the turbine. It is shown that the results obtained by employing the three approaches are very close, enforcing the validity of the analytically derived approximations, which may be used for wind turbine performance evaluation.

Mod-0A Wind Turbine in Block Island, Rhode Island

NASA Image and Video Library

1979-06-21

A Mod-0A 200-kilowatt wind turbine designed by National Aeronautics and Space Administration (NASA) Lewis Research Center and constructed in Block Island, Rhode Island. The wind turbine program was a joint program between NASA and the Energy Research and Development Administration (ERDA) during the 1970s to develop less expensive forms of energy. NASA Lewis was assigned the responsibility of developing large horizontal-axis wind turbines. The program included a series of increasingly powerful wind turbines, designated: Mod-0A, Mod-1, WTS-4, and Mod-5. The program’s first device was a Mod-0 100-kilowatt wind turbine test bed at NASA’s Plum Brook Station. This Mod-0A 200-kilowatt turbine, completed in 1977, was the program’s second-generation device. It included a 125-foot diameter blade atop a 100-foot tall tower. This early wind turbine was designed determine its operating problems, integrate with the local utilities, and assess the attitude of the local community. There were additional Mod-0A turbines built in Culebra, Puerto Rico; Clayton, New Mexico; and Oahu, Hawaii. The Mod-0A turbines suffered durability issues with the rotor blade and initially appeared unreliable. NASA engineers addressed the problems, and the turbines proved to be reliable and efficient devices that operated for a number of years. The information gained from these early models was vital to the design and improvement of the later generations.

Four-dimensional characterization of inflow to and wakes from a multi-MW turbine: overview of the Turbine Wake and Inflow Characterization Study (TWICS2011)

NASA Astrophysics Data System (ADS)

Lundquist, J. K.; Banta, R. M.; Pichugina, Y.; Brewer, A.; Alvarez, R. J.; Sandberg, S. P.; Kelley, N. D.; Aitken, M.; Clifton, A.; Mirocha, J. D.

2011-12-01

To support substantial deployment of renewably-generated electricity from the wind, critical information about the variability of wind turbine wakes in the real atmosphere from multi-MW turbines is required. The assessment of the velocity deficit and turbulence associated with industrial-scale turbines is a major issue for wind farm design, particularly with respect to the optimization of the spacing between turbines. The significant velocity deficit and turbulence generated by upstream turbines can reduce the power production and produce harmful vibrations in downstream turbines, which can lead to excess maintenance costs. The complexity of wake effects depends on many factors arising from both hardware (turbine size, rotor speed, and blade geometry, etc.) and from meteorological considerations such as wind velocity, gradients of wind across the turbine rotor disk, atmospheric stability, and atmospheric turbulence. To characterize the relationships between the meteorological inflow and turbine wakes, a collaborative field campaign was designed and carried out at the Department of Energy's National Wind Technology Center (NREL/NWTC) in south Boulder, Colorado, in spring 2011. This site often experiences channeled flow with a consistent wind direction, enabling robust statistics of wake velocity deficits and turbulence enhancements. Using both in situ and remote sensing instrumentation, measurements upwind and downwind of multi-megawatt wind turbine in complex terrain quantified the variability of wind turbine inflow and wakes from an industrial-scale turbine. The turbine of interest has a rated power of 2.3 MW, a rotor diameter of 100m, and a hub height of 80m. In addition to several meteorological towers, one extending to hub height (80m) and another extending above the top of the rotor disk (135m), a Triton mini-sodar and a Windcube lidar characterized the inflow to the turbine and the variability across the site. The centerpiece instrument of the TWICS campaign was the NOAA High Resolution Doppler lidar (HRDL), a scanning lidar which captured three-dimensional images of the turbine inflow and wake. Over several weeks, 48+ hours of HRDL observations during a variety of wind speed and atmospheric stability conditions were collected using three scanning strategies. Wake features such as lofting, meandering, intersection with the ground, and expansion factors are identified and discussed. Observations of a remarkably long-distance wake are presented and compared with existing wake models.

Modeling Smart Structure of Wind Turbine Blade

NASA Astrophysics Data System (ADS)

Qiao, Yin-hu; Han, Jiang; Zhang, Chun-yan; Chen, Jie-ping

2012-06-01

With the increasing size of wind turbine blades, the need for more sophisticated load control techniques has induced the interest for aerodynamic control systems with build-in intelligence on the blades. The paper aims to provide a way for modeling the adaptive wind turbine blades and analyze its ability for vibration suppress. It consists of the modeling of the adaptive wind turbine blades with the wire of piezoelectric material embedded in blade matrix, and smart sandwich structure of wind turbine blade. By using this model, an active vibration method which effectively suppresses the vibrations of the smart blade is designed.

Numerical modeling of wind turbine aerodynamic noise in the time domain.

PubMed

Lee, Seunghoon; Lee, Seungmin; Lee, Soogab

2013-02-01

Aerodynamic noise from a wind turbine is numerically modeled in the time domain. An analytic trailing edge noise model is used to determine the unsteady pressure on the blade surface. The far-field noise due to the unsteady pressure is calculated using the acoustic analogy theory. By using a strip theory approach, the two-dimensional noise model is applied to rotating wind turbine blades. The numerical results indicate that, although the operating and atmospheric conditions are identical, the acoustical characteristics of wind turbine noise can be quite different with respect to the distance and direction from the wind turbine.

Could Wind or Solar Energy Replace Diesel Generators for Aviation Ground Maintenance Operations?

DTIC Science & Technology

2013-04-17

power. Both of these systems depend on the sun to produce energy. Wind turbines depend on wind which results from the uneven heating of the earth...inefficient. In addition to these limitations, both systems are costly and their installation brings a number of challenges. For the wind turbines ...these challenges include: the obstruction created by the height of the turbines near airfields, the amount of land necessary for a 7 turbines wind farm

Engineering handbook on the atmospheric environmental guidelines for use in wind turbine generator development

NASA Technical Reports Server (NTRS)

Frost, W.; Long, B. H.; Turner, R. E.

1978-01-01

The guidelines are given in the form of design criteria relative to wind speed, wind shear, turbulence, wind direction, ice and snow loading, and other climatological parameters which include rain, hail, thermal effects, abrasive and corrosive effects, and humidity. This report is a presentation of design criteria in an engineering format which can be directly input to wind turbine generator design computations. Guidelines are also provided for developing specialized wind turbine generators or for designing wind turbine generators which are to be used in a special region of the United States.

Wall modeled LES of wind turbine wakes with geometrical effects

NASA Astrophysics Data System (ADS)

Bricteux, Laurent; Benard, Pierre; Zeoli, Stephanie; Moureau, Vincent; Lartigue, Ghislain; Vire, Axelle

2017-11-01

This study focuses on prediction of wind turbine wakes when geometrical effects such as nacelle, tower, and built environment, are taken into account. The aim is to demonstrate the ability of a high order unstructured solver called YALES2 to perform wall modeled LES of wind turbine wake turbulence. The wind turbine rotor is modeled using an Actuator Line Model (ALM) while the geometrical details are explicitly meshed thanks to the use of an unstructured grid. As high Reynolds number flows are considered, sub-grid scale models as well as wall modeling are required. The first test case investigated concerns a wind turbine flow located in a wind tunnel that allows to validate the proposed methodology using experimental data. The second test case concerns the simulation of a wind turbine wake in a complex environment (e.g. a Building) using realistic turbulent inflow conditions.

A quantitative analysis of the impact of wind turbines on operational Doppler weather radar data

NASA Astrophysics Data System (ADS)

Norin, L.

2015-02-01

In many countries wind turbines are rapidly growing in numbers as the demand for energy from renewable sources increases. The continued deployment of wind turbines can, however, be problematic for many radar systems, which are easily disturbed by turbines located in the radar line of sight. Wind turbines situated in the vicinity of Doppler weather radars can lead to erroneous precipitation estimates as well as to inaccurate wind and turbulence measurements. This paper presents a quantitative analysis of the impact of a wind farm, located in southeastern Sweden, on measurements from a nearby Doppler weather radar. The analysis is based on 6 years of operational radar data. In order to evaluate the impact of the wind farm, average values of all three spectral moments (the radar reflectivity factor, absolute radial velocity, and spectrum width) of the nearby Doppler weather radar were calculated, using data before and after the construction of the wind farm. It is shown that all spectral moments, from a large area at and downrange from the wind farm, were impacted by the wind turbines. It was also found that data from radar cells far above the wind farm (near 3 km altitude) were affected by the wind farm. It is shown that this in part can be explained by detection by the radar sidelobes and by scattering off increased levels of dust and turbulence. In a detailed analysis, using data from a single radar cell, frequency distributions of all spectral moments were used to study the competition between the weather signal and wind turbine clutter. It is shown that, when weather echoes give rise to higher reflectivity values than those of the wind farm, the negative impact of the wind turbines is greatly reduced for all spectral moments.

A quantitative analysis of the impact of wind turbines on operational Doppler weather radar data

NASA Astrophysics Data System (ADS)

Norin, L.

2014-08-01

In many countries wind turbines are rapidly growing in numbers as the demand for energy from renewable sources increases. The continued deployment of wind turbines can, however, be problematic for many radar systems, which are easily disturbed by turbines located in radar line-of-sight. Wind turbines situated in the vicinity of Doppler weather radars can lead to erroneous precipitation estimates as well as to inaccurate wind- and turbulence measurements. This paper presents a quantitative analysis of the impact of a wind farm, located in southeastern Sweden, on measurements from a nearby Doppler weather radar. The analysis is based on six years of operational radar data. In order to evaluate the impact of the wind farm, average values of all three spectral moments (the radar reflectivity factor, absolute radial velocity, and spectrum width) of the nearby Doppler weather radar were calculated, using data before and after the construction of the wind farm. It is shown that all spectral moments, from a large area at and downrange from the wind farm, were impacted by the wind turbines. It was also found that data from radar cells far above the wind farm (near 3 km altitude) were affected by the wind farm. We show that this is partly explained by changes in the atmospheric refractive index, bending the radar beams closer to the ground. In a detailed analysis, using data from a single radar cell, frequency distributions of all spectral moments were used to study the competition between the weather signal and wind turbine clutter. We show that when weather echoes give rise to higher reflectivity values than that of the wind farm, the negative impact of the wind turbines disappears for all spectral moments.

Wind | NREL

Science.gov Websites

Facilities Support Innovation and Collaboration Take a Tour of a Wind Turbine Featured Publications 2017 Recommended Practices Lidar-Enhanced Wind Turbine Control: Past, Present, and Future Development of a 5 MW wind turbine science and lowering the cost of wind-generated electricity alongside our partners. We

1.5 MW turbine installation at NREL's NWTC on Aug. 21

ScienceCinema

None

2017-12-27

Generating 20 percent of the nation's electricity from clean wind resources will require more and bigger wind turbines. NREL is installing two large wind turbines at the National Wind Technology Center to examine some of the industry's largest machines and address issues to expand wind energy on a commercial scale.

@NWTC Newsletter: Summer 2014 | Wind | NREL

Science.gov Websites

, Developmental Role in Major Wind Journal Boosting Wind Plant Power Output by 4%-5% through Coordinated Turbine . Part 2: Wind Farm Wake Models New Framework Transforms FAST Wind Turbine Modeling Tool (Fact Sheet ) Sensitivity Analysis of Wind Plant Performance to Key Turbine Design Parameters: A Systems Engineering

78 FR 33897 - Atlantic Wind Lease Sale 2 (ATLW2) Commercial Leasing for Wind Power on the Outer Continental...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-05

... megawatts (MW), that the turbines of the wind farm facility under commercial operations can produce at their rated wind speed as designated by the turbine's manufacturer. The nameplate capacity at the start of..., the nameplate capacity of the wind farm facility at the rated wind speed of the turbines would be 100...

For wind turbines in complex terrain, the devil is in the detail

NASA Astrophysics Data System (ADS)

Lange, Julia; Mann, Jakob; Berg, Jacob; Parvu, Dan; Kilpatrick, Ryan; Costache, Adrian; Chowdhury, Jubayer; Siddiqui, Kamran; Hangan, Horia

2017-09-01

The cost of energy produced by onshore wind turbines is among the lowest available; however, onshore wind turbines are often positioned in a complex terrain, where the wind resources and wind conditions are quite uncertain due to the surrounding topography and/or vegetation. In this study, we use a scale model in a three-dimensional wind-testing chamber to show how minor changes in the terrain can result in significant differences in the flow at turbine height. These differences affect not only the power performance but also the life-time and maintenance costs of wind turbines, and hence, the economy and feasibility of wind turbine projects. We find that the mean wind, wind shear and turbulence level are extremely sensitive to the exact details of the terrain: a small modification of the edge of our scale model, results in a reduction of the estimated annual energy production by at least 50% and an increase in the turbulence level by a factor of five in the worst-case scenario with the most unfavorable wind direction. Wind farm developers should be aware that near escarpments destructive flows can occur and their extent is uncertain thus warranting on-site field measurements.

Testing and Modeling of a 3-MW Wind Turbine Using Fully Coupled Simulation Codes (Poster)

DOE Office of Scientific and Technical Information (OSTI.GOV)

LaCava, W.; Guo, Y.; Van Dam, J.

This poster describes the NREL/Alstom Wind testing and model verification of the Alstom 3-MW wind turbine located at NREL's National Wind Technology Center. NREL,in collaboration with ALSTOM Wind, is studying a 3-MW wind turbine installed at the National Wind Technology Center(NWTC). The project analyzes the turbine design using a state-of-the-art simulation code validated with detailed test data. This poster describes the testing and the model validation effort, and provides conclusions about the performance of the unique drive train configuration used in this wind turbine. The 3-MW machine has been operating at the NWTC since March 2011, and drive train measurementsmore » will be collected through the spring of 2012. The NWTC testing site has particularly turbulent wind patterns that allow for the measurement of large transient loads and the resulting turbine response. This poster describes the 3-MW turbine test project, the instrumentation installed, and the load cases captured. The design of a reliable wind turbine drive train increasingly relies on the use of advanced simulation to predict structural responses in a varying wind field. This poster presents a fully coupled, aero-elastic and dynamic model of the wind turbine. It also shows the methodology used to validate the model, including the use of measured tower modes, model-to-model comparisons of the power curve, and mainshaft bending predictions for various load cases. The drivetrain is designed to only transmit torque to the gearbox, eliminating non-torque moments that are known to cause gear misalignment. Preliminary results show that the drivetrain is able to divert bending loads in extreme loading cases, and that a significantly smaller bending moment is induced on the mainshaft compared to a three-point mounting design.« less

A study on the power generation potential of mini wind turbine in east coast of Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Basrawi, Firdaus; Ismail, Izwan; Ibrahim, Thamir Khalil; Idris, Daing Mohamad Nafiz Daing; Anuar, Shahrani

2017-03-01

A small-scale wind turbine is an attractive renewable energy source, but its economic viability depends on wind speed. The aim of this study is to determine economic viability of small-scale wind turbine in East Coast of Peninsular Malaysia. The potential energy generated has been determined by wind speed data and power curved of. Hourly wind speed data of Kuantan throughout 2015 was collected as the input. Then, a model of wind turbine was developed based on a commercial a 300W mini wind turbine. It was found that power generation is 3 times higher during northeast monsoon season at 15 m elevation. This proved that the northeast monsoon season has higher potential in generating power by wind turbine in East Coast of Peninsular Malaysia. However, only a total of 153.4 kWh/year of power can be generated at this condition. The power generator utilization factor PGUI or capacity ratio was merely 0.06 and it is not technically viable. By increasing the height of wind turbine to 60 m elevation, power generation amount drastically increased to 344 kWh/year, with PGUI of 0.13. This is about two-thirds of PGUI for photovoltaic technology which is 0.21 at this site. If offshore condition was considered, power generation amount further increased to 1,328 kWh/year with PGUI of 0.51. Thus, for a common use of mini wind turbine that is usually installed on-site at low elevation, it has low power generation potential. But, if high elevation as what large wind turbine needed is implemented, it is technically viable option in East Coast of Peninsular Malaysia.

Wind turbine extraction from high spatial resolution remote sensing images based on saliency detection

NASA Astrophysics Data System (ADS)

Chen, Jingbo; Yue, Anzhi; Wang, Chengyi; Huang, Qingqing; Chen, Jiansheng; Meng, Yu; He, Dongxu

2018-01-01

The wind turbine is a device that converts the wind's kinetic energy into electrical power. Accurate and automatic extraction of wind turbine is instructive for government departments to plan wind power plant projects. A hybrid and practical framework based on saliency detection for wind turbine extraction, using Google Earth image at spatial resolution of 1 m, is proposed. It can be viewed as a two-phase procedure: coarsely detection and fine extraction. In the first stage, we introduced a frequency-tuned saliency detection approach for initially detecting the area of interest of the wind turbines. This method exploited features of color and luminance, was simple to implement, and was computationally efficient. Taking into account the complexity of remote sensing images, in the second stage, we proposed a fast method for fine-tuning results in frequency domain and then extracted wind turbines from these salient objects by removing the irrelevant salient areas according to the special properties of the wind turbines. Experiments demonstrated that our approach consistently obtains higher precision and better recall rates. Our method was also compared with other techniques from the literature and proves that it is more applicable and robust.

Analysis of axial-induction-based wind plant control using an engineering and a high-order wind plant model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Annoni, Jennifer; Gebraad, Pieter M. O.; Scholbrock, Andrew K.

2015-08-14

Wind turbines are typically operated to maximize their performance without considering the impact of wake effects on nearby turbines. Wind plant control concepts aim to increase overall wind plant performance by coordinating the operation of the turbines. This paper focuses on axial-induction-based wind plant control techniques, in which the generator torque or blade pitch degrees of freedom of the wind turbines are adjusted. The paper addresses discrepancies between a high-order wind plant model and an engineering wind plant model. Changes in the engineering model are proposed to better capture the effects of axial-induction-based control shown in the high-order model.

Proactive monitoring of a wind turbine array with lidar measurements, SCADA data and a data-driven RANS solver

NASA Astrophysics Data System (ADS)

Iungo, G.; Said, E. A.; Santhanagopalan, V.; Zhan, L.

2016-12-01

Power production of a wind farm and durability of wind turbines are strongly dependent on non-linear wake interactions occurring within a turbine array. Wake dynamics are highly affected by the specific site conditions, such as topography and local atmospheric conditions. Furthermore, contingencies through the life of a wind farm, such as turbine ageing and off-design operations, make prediction of wake interactions and power performance a great challenge in wind energy. In this work, operations of an onshore wind turbine array were monitored through lidar measurements, SCADA and met-tower data. The atmospheric wind field investing the wind farm was estimated by using synergistically the available data through five different methods, which are characterized by different confidence levels. By combining SCADA data and the lidar measurements, it was possible to estimate power losses connected with wake interactions. For this specific array, power losses were estimated to be 4% and 2% of the total power production for stable and convective atmospheric regimes, respectively. The entire dataset was then leveraged for the calibration of a data-driven RANS (DDRANS) solver for prediction of wind turbine wakes and power production. The DDRANS is based on a parabolic formulation of the Navier-Stokes equations with axisymmetry and boundary layer approximations, which allow achieving very low computational costs. Accuracy in prediction of wind turbine wakes and power production is achieved through an optimal tuning of the turbulence closure model. The latter is based on a mixing length model, which was developed based on previous wind turbine wake studies carried out through large eddy simulations and wind tunnel experiments. Several operative conditions of the wind farm under examination were reproduced through DDRANS for different stability regimes, wind directions and wind velocity. The results show that DDRANS is capable of achieving a good level of accuracy in prediction of power production and wake velocity field associated with the turbine array.

Improved reliability of wind turbine towers with active tuned mass dampers (ATMDs)

NASA Astrophysics Data System (ADS)

Fitzgerald, Breiffni; Sarkar, Saptarshi; Staino, Andrea

2018-04-01

Modern multi-megawatt wind turbines are composed of slender, flexible, and lightly damped blades and towers. These components exhibit high susceptibility to wind-induced vibrations. As the size, flexibility and cost of the towers have increased in recent years, the need to protect these structures against damage induced by turbulent aerodynamic loading has become apparent. This paper combines structural dynamic models and probabilistic assessment tools to demonstrate improvements in structural reliability when modern wind turbine towers are equipped with active tuned mass dampers (ATMDs). This study proposes a multi-modal wind turbine model for wind turbine control design and analysis. This study incorporates an ATMD into the tower of this model. The model is subjected to stochastically generated wind loads of varying speeds to develop wind-induced probabilistic demand models for towers of modern multi-megawatt wind turbines under structural uncertainty. Numerical simulations have been carried out to ascertain the effectiveness of the active control system to improve the structural performance of the wind turbine and its reliability. The study constructs fragility curves, which illustrate reductions in the vulnerability of towers to wind loading owing to the inclusion of the damper. Results show that the active controller is successful in increasing the reliability of the tower responses. According to the analysis carried out in this paper, a strong reduction of the probability of exceeding a given displacement at the rated wind speed has been observed.

Aerodynamic study of a blade with sine variation of chord length along the height for Darrieus wind turbine

NASA Astrophysics Data System (ADS)

Crunteanu, D. E.; Constantinescu, S. G.; Niculescu, M. L.

2013-10-01

The wind energy is deemed as one of the most durable energetic variants of the future because the wind resources are immense. Furthermore, one predicts that the small wind turbines will play a vital role in the urban environment. Unfortunately, the complexity and the price of pitch regulated small horizontal-axis wind turbines represent ones of the main obstacles to widespread the use in populated zones. In contrast to these wind turbines, the Darrieus wind turbines are simpler and their price is lower. Unfortunately, their blades run at high variations of angles of attack, in stall and post-stall regimes, which can induce significant vibrations, fatigue and even the wind turbine failure. For this reason, the present paper deals with a blade with sine variation of chord length along the height because it has better behavior in stall and post-stall regimes than the classic blade with constant chord length.

Description of signature scales in a floating wind turbine model wake subjected to varying turbulence intensity

NASA Astrophysics Data System (ADS)

Kadum, Hawwa; Rockel, Stanislav; Holling, Michael; Peinke, Joachim; Cal, Raul Bayon

2017-11-01

The wake behind a floating model horizontal axis wind turbine during pitch motion is investigated and compared to a fixed wind turbine wake. An experiment is conducted in an acoustic wind tunnel where hot-wire data are acquired at five downstream locations. At each downstream location, a rake of 16 hot-wires was used with placement of the probes increasing radially in the vertical, horizontal, and diagonally at 45 deg. In addition, the effect of turbulence intensity on the floating wake is examined by subjecting the wind turbine to different inflow conditions controlled through three settings in the wind tunnel grid, a passive and two active protocols, thus varying in intensity. The wakes are inspected by statistics of the point measurements, where the various length/time scales are considered. The wake characteristics for a floating wind turbine are compared to a fixed turbine, and uncovering its features; relevant as the demand for exploiting deep waters in wind energy is increasing.

Investigation on installation of offshore wind turbines

NASA Astrophysics Data System (ADS)

Wang, Wei; Bai, Yong

2010-06-01

Wind power has made rapid progress and should gain significance as an energy resource, given growing interest in renewable energy and clean energy. Offshore wind energy resources have attracted significant attention, as, compared with land-based wind energy resources, offshore wind energy resources are more promising candidates for development. Sea winds are generally stronger and more reliable and with improvements in technology, the sea has become a hot spot for new designs and installation methods for wind turbines. In the present paper, based on experience building offshore wind farms, recommended foundation styles have been examined. Furthermore, wave effects have been investigated. The split installation and overall installation have been illustrated. Methods appropriate when installing a small number of turbines as well as those useful when installing large numbers of turbines were analyzed. This investigation of installation methods for wind turbines should provide practical technical guidance for their installation.

Determination of the wind power systems load to achieve operation in the maximum energy area

NASA Astrophysics Data System (ADS)

Chioncel, C. P.; Tirian, G. O.; Spunei, E.; Gillich, N.

2018-01-01

This paper analyses the operation of the wind turbine, WT, in the maximum power point, MPP, by linking the load of the Permanent Magnet Synchronous Generator, PMSG, with the wind speed value. The load control methods at wind power systems aiming an optimum performance in terms of energy are based on the fact that the energy captured by the wind turbine significantly depends on the mechanical angular speed of the wind turbine. The presented control method consists in determining the optimal mechanical angular speed, ωOPTIM, using an auxiliary low power wind turbine, WTAUX, operating without load, at maximum angular velocity, ωMAX. The method relies on the fact that the ratio ωOPTIM/ωMAX has a constant value for a given wind turbine and does not depend on the time variation of the wind speed values.

Wind turbines and idiopathic symptoms: The confounding effect of concurrent environmental exposures.

PubMed

Blanes-Vidal, Victoria; Schwartz, Joel

2016-01-01

Whether or not wind turbines pose a risk to human health is a matter of heated debate. Personal reactions to other environmental exposures occurring in the same settings as wind turbines may be responsible of the reported symptoms. However, these have not been accounted for in previous studies. We investigated whether there is an association between residential proximity to wind turbines and idiopathic symptoms, after controlling for personal reactions to other environmental co-exposures. We assessed wind turbine exposures in 454 residences as the distance to the closest wind turbine (Dw) and number of wind turbines <1000m (Nw1000). Information on symptoms, demographics and personal reactions to exposures was obtained by a blind questionnaire. We identified confounders using confounders' selection criteria and used adjusted logistic regression models to estimate associations. When controlling only for socio-demographic characteristics, log10Dw was associated with "unnatural fatigue" (ORadj=0.38, 95%CI=0.15-1.00) and "difficulty concentrating" (ORadj=0.26, 95%CI=0.08-0.83) and Nw1000 was associated with "unnatural fatigue" (ORadj=1.35, 95%CI=1.07-1.70) and "headache" (ORadj=1.26, 95%CI=1.00-1.58). After controlling for personal reactions to noise from sources different from wind turbines and agricultural odor exposure, we did not observe a significant relationship between residential proximity to wind turbines and symptoms and the parameter estimates were attenuated toward zero. Wind turbines-health associations can be confounded by personal reactions to other environmental co-exposures. Isolated associations reported in the literature may be due to confounding bias. Copyright © 2016 Elsevier Inc. All rights reserved.

The effect of wind turbine noise on sleep and quality of life: A systematic review and meta-analysis of observational studies.

PubMed

Onakpoya, Igho J; O'Sullivan, Jack; Thompson, Matthew J; Heneghan, Carl J

2015-09-01

Noise generated by wind turbines has been reported to affect sleep and quality of life (QOL), but the relationship is unclear. Our objective was to explore the association between wind turbine noise, sleep disturbance and quality of life, using data from published observational studies. We searched Medline, Embase, Global Health and Google Scholar databases. No language restrictions were imposed. Hand searches of bibliography of retrieved full texts were also conducted. The reporting quality of included studies was assessed using the STROBE guidelines. Two reviewers independently determined the eligibility of studies, assessed the quality of included studies, and extracted the data. We included eight studies with a total of 2433 participants. All studies were cross-sectional, and the overall reporting quality was moderate. Meta-analysis of six studies (n=2364) revealed that the odds of being annoyed is significantly increased by wind turbine noise (OR: 4.08; 95% CI: 2.37 to 7.04; p<0.00001). The odds of sleep disturbance was also significantly increased with greater exposure to wind turbine noise (OR: 2.94; 95% CI: 1.98 to 4.37; p<0.00001). Four studies reported that wind turbine noise significantly interfered with QOL. Further, visual perception of wind turbine generators was associated with greater frequency of reported negative health effects. In conclusion, there is some evidence that exposure to wind turbine noise is associated with increased odds of annoyance and sleep problems. Individual attitudes could influence the type of response to noise from wind turbines. Experimental and observational studies investigating the relationship between wind turbine noise and health are warranted. Copyright © 2015 Elsevier Ltd. All rights reserved.

Electromagnetic Calculation of Combined Earthing System with Ring Earth Electrode and Vertical Rods for Wind Turbine

NASA Astrophysics Data System (ADS)

Fujii, Toshiaki; Yasuda, Yoh; Ueda, Toshiaki

With the worldwide spread of wind turbine installations, various problems such as landscape issues, bird strikes and grid connections have arisen. Protection of wind turbines from lightning is cited as one of the main problems. Wind turbines are often struck by lightning because of their open-air locations, such as in mountainous areas, and their special configuration and very-high construction. Especially, low-voltage and control circuits can fail or suffer burnout while blades can incur serious damage if struck by lightning. Wind turbine failures caused by lightning strikes account for approximately 25% of all failures. The problem is regarded as a global one that needs immediate resolution. It is important to understand the impedance characteristics of wind turbine earthing systems from the viewpoint of lightning protection. A report from IEC TR61400-24 recommends a “ring earth electrode”. This was originally defined in IEC 61024 (currently revised and re-numbered as IEC 62305), where such an electrode is recommended to reduce touch and step voltages in households and buildings. IEC TR61400-24 also recommended additional electrodes of vertical or horizontal rods. However, these concepts have not been fully discussed from the viewpoint of its application to wind turbines. To confirm the effect of a combination of a ring earth electrode and additional vertical rods for protection of a wind turbine, this report uses the Finite Difference Time Domain (FDTD) method to present an electromagnetic transient analysis on such a wind turbine earthing system. The results show that an optimal combination can be arranged from viewpoints of lightning protection and construction cost. Thus, this report discusses how to establish a quantitative design methodology of the wind turbine earthing system to provide effective lightning protection.

Dissipation of turbulence in the wake of a wind turbine

NASA Astrophysics Data System (ADS)

Lundquist, J. K.; Bariteau, L.

2013-12-01

The wake of a wind turbine is characterized by increased turbulence and decreased wind speed. Turbines are generally deployed in large groups in wind farms, and so the behavior of an individual wake as it merges with other wakes and propagates downwind is of great importance in assessing wind farm power production as well as impacts of wind energy deployment on local and regional environments. The rate of turbulence dissipation in the wake quantifies the wake behavior as it propagates. In situ field measurements of turbulence dissipation rate in the wake of wind turbines have not been previously collected although correct modeling of dissipation rate is required for accurate simulations of wake evolution. In Fall 2012, we collected in situ measurements of winds and turbulence dissipation from the wake region of a multi-MW turbine, using the University of Colorado at Boulder's Tethered Lifting System (TLS). The TLS is a unique state-of-the-art tethersonde, proven in numerous boundary-layer field experiments to be able to measure turbulence kinetic energy dissipation rates. Ambient flow measurements were provided from sonic anemometers on a meteorological tower located upwind of the turbine, from a profiling lidar upwind, and from a scanning lidar measuring both inflow to and wake from the turbine. Measurements collected within the wake indicate that dissipation rates are higher in the turbine wake than in the ambient flow. Profiles of dissipation and turbulence throughout the rotor disk suggest that dissipation peaks near the hub height of the turbine. Suggestions for incorporating this information into wind turbine modeling approaches will be provided.

Onshore industrial wind turbine locations for the United States up to March 2014

USGS Publications Warehouse

Diffendorfer, James E.; Kramer, Louisa; Ancona, Zachary H.; Garrity, Christopher P.

2015-01-01

Wind energy is a rapidly growing form of renewable energy in the United States. While summary information on the total amounts of installed capacity are available by state, a free, centralized, national, turbine-level, geospatial dataset useful for scientific research, land and resource management, and other uses did not exist. Available in multiple formats and in a web application, these public domain data provide industrial-scale onshore wind turbine locations in the United States up to March 2014, corresponding facility information, and turbine technical specifications. Wind turbine records have been collected and compiled from various public sources, digitized or position verified from aerial imagery, and quality assured and quality controlled. Technical specifications for turbines were assigned based on the wind turbine make and model as described in public literature. In some cases, turbines were not seen in imagery or turbine information did not exist or was difficult to obtain. Uncertainty associated with these is recorded in a confidence rating.

Onshore industrial wind turbine locations for the United States up to March 2014.

PubMed

Diffendorfer, Jay E; Kramer, Louisa A; Ancona, Zach H; Garrity, Christopher P

2015-11-24

Wind energy is a rapidly growing form of renewable energy in the United States. While summary information on the total amounts of installed capacity are available by state, a free, centralized, national, turbine-level, geospatial dataset useful for scientific research, land and resource management, and other uses did not exist. Available in multiple formats and in a web application, these public domain data provide industrial-scale onshore wind turbine locations in the United States up to March 2014, corresponding facility information, and turbine technical specifications. Wind turbine records have been collected and compiled from various public sources, digitized or position verified from aerial imagery, and quality assured and quality controlled. Technical specifications for turbines were assigned based on the wind turbine make and model as described in public literature. In some cases, turbines were not seen in imagery or turbine information did not exist or was difficult to obtain. Uncertainty associated with these is recorded in a confidence rating.

Wind turbines, flicker, and photosensitive epilepsy: characterizing the flashing that may precipitate seizures and optimizing guidelines to prevent them.

PubMed

Harding, Graham; Harding, Pamela; Wilkins, Arnold

2008-06-01

Wind turbines are known to produce shadow flicker by interruption of sunlight by the turbine blades. Known parameters of the seizure provoking effect of flicker, i.e., contrast, frequency, mark-space ratio, retinal area stimulated and percentage of visual cortex involved were applied to wind turbine features. The proportion of patients affected by viewing wind turbines expressed as distance in multiples of the hub height of the turbine showed that seizure risk does not decrease significantly until the distance exceeds 100 times the hub height. Since risk does not diminish with viewing distance, flash frequency is therefore the critical factor and should be kept to a maximum of three per second, i.e., sixty revolutions per minute for a three-bladed turbine. On wind farms the shadows cast by one turbine on another should not be viewable by the public if the cumulative flash rate exceeds three per second. Turbine blades should not be reflective.

Onshore industrial wind turbine locations for the United States up to March 2014

PubMed Central

Diffendorfer, Jay E.; Kramer, Louisa A.; Ancona, Zach H.; Garrity, Christopher P.

2015-01-01

Wind energy is a rapidly growing form of renewable energy in the United States. While summary information on the total amounts of installed capacity are available by state, a free, centralized, national, turbine-level, geospatial dataset useful for scientific research, land and resource management, and other uses did not exist. Available in multiple formats and in a web application, these public domain data provide industrial-scale onshore wind turbine locations in the United States up to March 2014, corresponding facility information, and turbine technical specifications. Wind turbine records have been collected and compiled from various public sources, digitized or position verified from aerial imagery, and quality assured and quality controlled. Technical specifications for turbines were assigned based on the wind turbine make and model as described in public literature. In some cases, turbines were not seen in imagery or turbine information did not exist or was difficult to obtain. Uncertainty associated with these is recorded in a confidence rating. PMID:26601687

A 20-KW Wind Energy Conversion System (WECS) at the Marine Corps Air Station, Kaneohe, Hawaii.

DTIC Science & Technology

1983-01-01

of propellers and that vertical-axis wind turbines would be more efficient. Several turbines such as the Darrieus and gyro-mill, of this type are... wind turbines , wind systems siting, alternate energy systems, remote site power generation. 20 ABSTRACT (Con!,,u,. - r r... .. do I(3 lI - d #,d e...Corps Air Station (MCAS) Kaneohe Bay, Hawaii. The wind turbine generator chosen for the evaluation was a horizontal-axis-propeller- downwind rotor

United States Air Force Academy (USAFA) Vertical Axis Wind Turbine.

DTIC Science & Technology

1980-09-01

Rotors, SAND76-0131. Albuquerque: July 1977. 10. Oliver, R.C. and P.R. Nixon. "Design Procedure for Coupling Savonius and Darrieus Wind Turbines ", Air...May 17-20, 1976. -65- 16. Blackwell, B.F., R.E. Sheldahl, and L.V. Feltz. Wind Tunnel Performance Data for the Darrieus Wind Turbine with NACA 0012...a 5.8 m/s (13 mph) wind . At 100 rpm, the Darrieus turbine would be fully self-sustaining and acceleration would continue to an operating tip speed

The California Central Coast Research Partnership: Building Relationships, Partnerships and Paradigms for University-Industry Collaboration

DTIC Science & Technology

2013-03-25

funded project, sensors and a control system have been installed onto the 3 kW capacity wind turbine of the Cal Poly Wind Power Research Center, which is...to full operation. This wind turbine is used to educate students for careers in the wind energy industry and related professional fields and to...conduct research into the application of advanced wind turbine technologies from large turbines onto small tur- bines. In this project, a control system

Assessment and Methods for Supply-Following Loads in Modern Electricity Grids with Deep Renewables Penetration

DTIC Science & Technology

2013-12-18

from a combination of increased electricity demand, poor output from the large contingent of wind turbines in Texas (the most in the U.S.), and...2.8 GW of wind power farms in California are onshore, consist of low-altitude (m) wind turbines , and are located in 8 of California’s 58 counties...offshore wind turbines , and the improvement of turbine efficiency will enable massive potential wind resources. Looking more closely at the temporal

Quantifying array losses due to spacing and staggering in offshore wind farms (Invited)

NASA Astrophysics Data System (ADS)

Archer, C. L.; Mirzaeisefat, S.; Lee, S.; Xie, S.

2013-12-01

The layout of wind turbines can have an impact on the power production of a wind farm. Design variables that define the layout of wind turbines within a wind farm include: orientation of the rows with respect to the prevailing wind direction, size and shape of the wind farm, spacing between turbines, and alignment of the turbines (i.e., whether in-line or staggered with one another). There are no universal layout recommendations for offshore wind farms, partly because isolating the contribution of each individual design variable is impossible at existing offshore wind farms, where multiple effects overlap non-linearly on one another, and partly because analyzing the sensitivity to design variables requires sophisticated and computer-intensive numerical codes, such as large-eddy simulations (LES), that can simulate the small-scale turbulent features of turbine wakes. The National Renewable Energy Laboratory (NREL) developed the only publicly available and open-source LES code that is capable of resolving wind turbine blades as rotating actuator lines (not fixed disks), includes both neutral and unstable atmospheric conditions (stable case is currently under development), and does not rely on periodic boundary conditions. This code, named Simulator for Offshore/Onshore Wind Farm Applications (SOWFA), is based on OpenFOAM and has been used successfully in the past for turbulent wake simulations. Here we address the issue of quantifying two design variables: turbine spacing (both along and across the prevailing wind direction) and alignment (in-line or staggered for consecutive rows). SOWFA is used to simulate an existing offshore wind farm in Lillgrund (Sweden), consisting of 48 Siemens 2.3 MW turbines with spacing of 3.2D across and 4.3D along the prevailing wind direction and without staggering, where D is the turbine diameter (93 m). This spacing is exceptionally tight, to our knowledge the tightest of all modern wind farms. While keeping the area and the shape of the farm constant, we design several new Lillgrund farm layouts with and without staggering, with increased spacing in each direction individually and in both directions together, and with various wind directions and atmospheric stabilities. We found that the average wind power generated per turbine is increased by ~32% (from 696 kW to 922 kW) if both staggering and doubling of the across-spacing are implemented simultaneously in a neutral stability case. Wake losses are quantified in terms of average power in the first (upwind) row of wind turbines in the control case, representative of the power that could be generated if there were no wakes, over the average power of all the wind turbines in the farm. Wake losses at Lillgrund are relatively high due to the tight packing, of the order of 35%, but smart combinations of staggering and doubling of turbine spacing can reduce them to 15%-26%. In summary, we provide estimates of the losses/gains associated with individual and combined changes in two design variables, spacing and staggering, under various atmospheric stabilities, wind directions, and wind speeds. These estimates will be useful to the wind industry to optimize a wind project because the effects of alternative layouts can be quantified quickly with respect to total power, capacity factor, and number of wind turbines, all of which can ultimately be converted to actual costs or savings.

Quantifying array losses due to spacing and staggering in offshore wind farms (Invited)

NASA Astrophysics Data System (ADS)

Archer, C. L.; Mirzaeisefat, S.; Lee, S.; Xie, S.

2011-12-01

The layout of wind turbines can have an impact on the power production of a wind farm. Design variables that define the layout of wind turbines within a wind farm include: orientation of the rows with respect to the prevailing wind direction, size and shape of the wind farm, spacing between turbines, and alignment of the turbines (i.e., whether in-line or staggered with one another). There are no universal layout recommendations for offshore wind farms, partly because isolating the contribution of each individual design variable is impossible at existing offshore wind farms, where multiple effects overlap non-linearly on one another, and partly because analyzing the sensitivity to design variables requires sophisticated and computer-intensive numerical codes, such as large-eddy simulations (LES), that can simulate the small-scale turbulent features of turbine wakes. The National Renewable Energy Laboratory (NREL) developed the only publicly available and open-source LES code that is capable of resolving wind turbine blades as rotating actuator lines (not fixed disks), includes both neutral and unstable atmospheric conditions (stable case is currently under development), and does not rely on periodic boundary conditions. This code, named Simulator for Offshore/Onshore Wind Farm Applications (SOWFA), is based on OpenFOAM and has been used successfully in the past for turbulent wake simulations. Here we address the issue of quantifying two design variables: turbine spacing (both along and across the prevailing wind direction) and alignment (in-line or staggered for consecutive rows). SOWFA is used to simulate an existing offshore wind farm in Lillgrund (Sweden), consisting of 48 Siemens 2.3 MW turbines with spacing of 3.2D across and 4.3D along the prevailing wind direction and without staggering, where D is the turbine diameter (93 m). This spacing is exceptionally tight, to our knowledge the tightest of all modern wind farms. While keeping the area and the shape of the farm constant, we design several new Lillgrund farm layouts with and without staggering, with increased spacing in each direction individually and in both directions together, and with various wind directions and atmospheric stabilities. We found that the average wind power generated per turbine is increased by ~32% (from 696 kW to 922 kW) if both staggering and doubling of the across-spacing are implemented simultaneously in a neutral stability case. Wake losses are quantified in terms of average power in the first (upwind) row of wind turbines in the control case, representative of the power that could be generated if there were no wakes, over the average power of all the wind turbines in the farm. Wake losses at Lillgrund are relatively high due to the tight packing, of the order of 35%, but smart combinations of staggering and doubling of turbine spacing can reduce them to 15%-26%. In summary, we provide estimates of the losses/gains associated with individual and combined changes in two design variables, spacing and staggering, under various atmospheric stabilities, wind directions, and wind speeds. These estimates will be useful to the wind industry to optimize a wind project because the effects of alternative layouts can be quantified quickly with respect to total power, capacity factor, and number of wind turbines, all of which can ultimately be converted to actual costs or savings.

Calculation of transient potential rise on the wind turbine struck by lightning.

PubMed

Xiaoqing, Zhang

2014-01-01

A circuit model is proposed in this paper for calculating the transient potential rise on the wind turbine struck by lightning. The model integrates the blade, sliding contact site, and tower and grounding system of the wind turbine into an equivalent circuit. The lightning current path from the attachment point to the ground can be fully described by the equivalent circuit. The transient potential responses are obtained in the different positions on the wind turbine by solving the circuit equations. In order to check the validity of the model, the laboratory measurement is made with a reduced-scale wind turbine. The measured potential waveform is compared with the calculated one and a better agreement is shown between them. The practical applicability of the model is also examined by a numerical example of a 2 MW Chinese-built wind turbine.

Mixed H2/H∞ pitch control of wind turbine with a Markovian jump model

NASA Astrophysics Data System (ADS)

Lin, Zhongwei; Liu, Jizhen; Wu, Qiuwei; Niu, Yuguang

2018-01-01

This paper proposes a Markovian jump model and the corresponding H2/H∞ control strategy for the wind turbine driven by the stochastic switching wind speed, which can be used to regulate the generator speed in order to harvest the rated power while reducing the fatigue loads on the mechanical side of wind turbine. Through sampling the low-frequency wind speed data into separate intervals, the stochastic characteristic of the steady wind speed can be represented as a Markov process, while the high-frequency wind speed in the each interval is regarded as the disturbance input. Then, the traditional operating points of wind turbine can be divided into separate subregions correspondingly, where the model parameters and the control mode can be fixed in each mode. Then, the mixed H2/H∞ control problem is discussed for such a class of Markovian jump wind turbine working above the rated wind speed to guarantee both the disturbance rejection and the mechanical loads objectives, which can reduce the power volatility and the generator torque fluctuation of the whole transmission mechanism efficiently. Simulation results for a 2 MW wind turbine show the effectiveness of the proposed method.

76 FR 381 - Notice of Availability of the Draft Environmental Impact Statement/Draft Environmental Impact...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-04

... project will consist of approximately 134 wind turbines (1.5 to 3.0 MW each), an overhead and underground... the number of wind turbines, authorization of the 113 wind turbines, but moving them away from... Statement/Draft Environmental Impact Report for the Iberdrola Renewable/Pacific Wind Development Tule Wind...

The development and testing of a novel cross axis wind turbine

NASA Astrophysics Data System (ADS)

Chong, W. T.; Muzammil, W. K.; Gwani, M.; Wong, K. H.; Fazlizan, A.; Wang, C. T.; Poh, S. C.

2016-06-01

A novel cross axis wind turbine (CAWT) which comprises of a cross axis blades arrangement was presented and investigated experimentally. The CAWT is a new type of wind turbine that extracts wind energy from airflow coming from the horizontal and vertical directions. The wind turbine consists of three vertical blades and six horizontal blades arranged in a cross axis orientation. Hubs in the middle of the CAWT link the horizontal and vertical blades through connectors to form the CAWT. The study used a 45° deflector to guide the oncoming airflow upward (vertical wind direction). The results from the study showed that the CAWT produced significant improvements in power output and rotational speed performance compared to a conventional straight-bladed vertical axis wind turbine (VAWT).

Advanced Modeling System for Optimization of Wind Farm Layout and Wind Turbine Sizing Using a Multi-Level Extended Pattern Search Algorithm

DOE Office of Scientific and Technical Information (OSTI.GOV)

DuPont, Bryony; Cagan, Jonathan; Moriarty, Patrick

This paper presents a system of modeling advances that can be applied in the computational optimization of wind plants. These modeling advances include accurate cost and power modeling, partial wake interaction, and the effects of varying atmospheric stability. To validate the use of this advanced modeling system, it is employed within an Extended Pattern Search (EPS)-Multi-Agent System (MAS) optimization approach for multiple wind scenarios. The wind farm layout optimization problem involves optimizing the position and size of wind turbines such that the aerodynamic effects of upstream turbines are reduced, which increases the effective wind speed and resultant power at eachmore » turbine. The EPS-MAS optimization algorithm employs a profit objective, and an overarching search determines individual turbine positions, with a concurrent EPS-MAS determining the optimal hub height and rotor diameter for each turbine. Two wind cases are considered: (1) constant, unidirectional wind, and (2) three discrete wind speeds and varying wind directions, each of which have a probability of occurrence. Results show the advantages of applying the series of advanced models compared to previous application of an EPS with less advanced models to wind farm layout optimization, and imply best practices for computational optimization of wind farms with improved accuracy.« less

Volumetric LiDAR scanning of a wind turbine wake and comparison with a 3D analytical wake model

NASA Astrophysics Data System (ADS)

Carbajo Fuertes, Fernando; Porté-Agel, Fernando

2016-04-01

A correct estimation of the future power production is of capital importance whenever the feasibility of a future wind farm is being studied. This power estimation relies mostly on three aspects: (1) a reliable measurement of the wind resource in the area, (2) a well-established power curve of the future wind turbines and, (3) an accurate characterization of the wake effects; the latter being arguably the most challenging one due to the complexity of the phenomenon and the lack of extensive full-scale data sets that could be used to validate analytical or numerical models. The current project addresses the problem of obtaining a volumetric description of a full-scale wake of a 2MW wind turbine in terms of velocity deficit and turbulence intensity using three scanning wind LiDARs and two sonic anemometers. The characterization of the upstream flow conditions is done by one scanning LiDAR and two sonic anemometers, which have been used to calculate incoming vertical profiles of horizontal wind speed, wind direction and an approximation to turbulence intensity, as well as the thermal stability of the atmospheric boundary layer. The characterization of the wake is done by two scanning LiDARs working simultaneously and pointing downstream from the base of the wind turbine. The direct LiDAR measurements in terms of radial wind speed can be corrected using the upstream conditions in order to provide good estimations of the horizontal wind speed at any point downstream of the wind turbine. All this data combined allow for the volumetric reconstruction of the wake in terms of velocity deficit as well as turbulence intensity. Finally, the predictions of a 3D analytical model [1] are compared to the 3D LiDAR measurements of the wind turbine. The model is derived by applying the laws of conservation of mass and momentum and assuming a Gaussian distribution for the velocity deficit in the wake. This model has already been validated using high resolution wind-tunnel measurements and large-eddy simulation (LES) data of miniature wind turbine wakes, as well as LES data of real-scale wind-turbine wakes, but not yet with full-scale wind turbine wake measurements. [1] M. Bastankhah and F. Porté-Agel. A New Analytical Model For Wind-Turbine Wakes, in Renewable Energy, vol. 70, p. 116-123, 2014.

Evaluation of different inertial control methods for variable-speed wind turbines simulated by fatigue, aerodynamic, structures and turbulence (FAST)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Xiao; Gao, Wenzhong; Scholbrock, Andrew

To mitigate the degraded power system inertia and undesirable primary frequency response caused by large-scale wind power integration, the frequency support capabilities of variable-speed wind turbines is studied in this work. This is made possible by controlled inertial response, which is demonstrated on a research turbine - controls advanced research turbine, 3-bladed (CART3). Two distinct inertial control (IC) methods are analysed in terms of their impacts on the grids and the response of the turbine itself. The released kinetic energy in the IC methods are determined by the frequency measurement or shaped active power reference in the turbine speed-power plane.more » The wind turbine model is based on the high-fidelity turbine simulator fatigue, aerodynamic, structures and turbulence, which constitutes the aggregated wind power plant model with the simplified power converter model. The IC methods are implemented over the baseline CART3 controller, evaluated in the modified 9-bus and 14-bus testing power grids considering different wind speeds and different wind power penetration levels. The simulation results provide various insights on designing such kinds of ICs. The authors calculate the short-term dynamic equivalent loads and give a discussion about the turbine structural loadings related to the inertial response.« less

An examination of loads and responses of a wind turbine undergoing variable-speed operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wright, A.D.; Buhl, M.L. Jr.; Bir, G.S.

1996-11-01

The National Renewable Energy Laboratory has recently developed the ability to predict turbine loads and responses for machines undergoing variable-speed operation. The wind industry has debated the potential benefits of operating wind turbine sat variable speeds for some time. Turbine system dynamic responses (structural response, resonance, and component interactions) are an important consideration for variable-speed operation of wind turbines. The authors have implemented simple, variable-speed control algorithms for both the FAST and ADAMS dynamics codes. The control algorithm is a simple one, allowing the turbine to track the optimum power coefficient (C{sub p}). The objective of this paper is tomore » show turbine loads and responses for a particular two-bladed, teetering-hub, downwind turbine undergoing variable-speed operation. The authors examined the response of the machine to various turbulent wind inflow conditions. In addition, they compare the structural responses under fixed-speed and variable-speed operation. For this paper, they restrict their comparisons to those wind-speed ranges for which limiting power by some additional control strategy (blade pitch or aileron control, for example) is not necessary. The objective here is to develop a basic understanding of the differences in loads and responses between the fixed-speed and variable-speed operation of this wind turbine configuration.« less

7 CFR Appendix A to Part 4280 - Technical Reports for Projects With Total Eligible Project Costs of $200,000 or Less

Code of Federal Regulations, 2011 CFR

2011-01-01

... of the wind turbine is 100kW or smaller and with a generator hub height of 120 feet or less. Small... demonstrate the amount of local wind resource where the small wind turbine is to be installed. Indicate the... of the individual wind turbine(s) is larger than 100kW. (a) Qualifications of key project service...

7 CFR Appendix A to Part 4280 - Technical Reports for Projects With Total Eligible Project Costs of $200,000 or Less

Code of Federal Regulations, 2010 CFR

2010-01-01

... of the wind turbine is 100kW or smaller and with a generator hub height of 120 feet or less. Small... demonstrate the amount of local wind resource where the small wind turbine is to be installed. Indicate the... of the individual wind turbine(s) is larger than 100kW. (a) Qualifications of key project service...

Assessment and Optimization of Lidar Measurement Availability for Wind Turbine Control: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davoust, S.; Jehu, A.; Bouillet, M.

2014-05-01

Turbine-mounted lidars provide preview measurements of the incoming wind field. By reducing loads on critical components and increasing the potential power extracted from the wind, the performance of wind turbine controllers can be improved [2]. As a result, integrating a light detection and ranging (lidar) system has the potential to lower the cost of wind energy. This paper presents an evaluation of turbine-mounted lidar availability. Availability is a metric which measures the proportion of time the lidar is producing controller-usable data, and is essential when a wind turbine controller relies on a lidar. To accomplish this, researchers from Avent Lidarmore » Technology and the National Renewable Energy Laboratory first assessed and modeled the effect of extreme atmospheric events. This shows how a multirange lidar delivers measurements for a wide variety of conditions. Second, by using a theoretical approach and conducting an analysis of field feedback, we investigated the effects of the lidar setup on the wind turbine. This helps determine the optimal lidar mounting position at the back of the nacelle, and establishes a relationship between availability, turbine rpm, and lidar sampling time. Lastly, we considered the role of the wind field reconstruction strategies and the turbine controller on the definition and performance of a lidar's measurement availability.« less

A Biomimetic Ultrasonic Whistle for Use as a Bat Deterrent on Wind Turbines

NASA Astrophysics Data System (ADS)

Sievert, Paul; Seyed-Aghazadeh, Banafsheh; Carlson, Daniel; Dowling, Zara; Modarres-Sadeghi, Yahya

2016-11-01

As wind energy continues to gain worldwide prominence, more and more turbines are detrimentally influencing bat colonies. In 2012 alone, an estimated 600,000 bats were killed by wind turbines in the United States. Bats show a tendency to fly towards turbines. The objective of this work is to deter bats from the proximity of the swept area of operational wind turbine blades. Established field studies have shown that bats avoid broadband ultrasonic noise on the same frequency spectrum as their echolocation chirps. A biomimetic ultrasonic pulse generator for use as a bat deterrent on wind turbines is designed and studied experimentally. This device, which works based on the fundamentals of flow-induced oscillations of a flexible sheet is a whistle-like device inspired by a bat larynx, mechanically powered via air flow on a wind turbine blade. Current device prototypes have proven robust at producing ultrasound across the 20 - 70 kHz range for flow inlet velocities of 4 - 14 m/s. Ultimately, a deterrent as described here could provide a reliable, cost-effective means of alerting bats to the presence of moving turbine blades, reducing bat mortality at wind facilities, and reducing regulatory uncertainty for wind facility developers. The financial support provided by the US Department of Energy, and the Massachusetts Clean Energy center is acknowledged.

Effectiveness enhancement of a cycloidal wind turbine by individual active control of blade motion

NASA Astrophysics Data System (ADS)

Hwang, In Seong; Lee, Yun Han; Kim, Seung Jo

2007-04-01

In this paper, a research for the effectiveness enhancement of a Cycloidal Wind Turbine by individual active control of blade motion is described. To improve the performance of the power generation system, which consists of several straight blades rotating about axis in parallel direction, the cycloidal blade system and the individual active blade control method are adopted. It has advantages comparing with horizontal axis wind turbine or conventional vertical axis wind turbine because it maintains optimal blade pitch angles according to wind speed, wind direction and rotor rotating speed to produce high electric power at any conditions. It can do self-starting and shows good efficiency at low wind speed and complex wind condition. Optimal blade pitch angle paths are obtained through CFD analysis according to rotor rotating speed and wind speed. The individual rotor blade control system consists of sensors, actuators and microcontroller. To realize the actuating device, servo motors are installed to each rotor blade. Actuating speed and actuating force are calculated to compare with the capacities of servo motor, and some delays of blade pitch angles are corrected experimentally. Performance experiment is carried out by the wind blowing equipment and Labview system, and the rotor rotates from 50 to 100 rpm according to the electric load. From this research, it is concluded that developing new vertical axis wind turbine, Cycloidal Wind Turbine which is adopting individual active blade pitch control method can be a good model for small wind turbine in urban environment.

Multi-Objective Random Search Algorithm for Simultaneously Optimizing Wind Farm Layout and Number of Turbines

NASA Astrophysics Data System (ADS)

Feng, Ju; Shen, Wen Zhong; Xu, Chang

2016-09-01

A new algorithm for multi-objective wind farm layout optimization is presented. It formulates the wind turbine locations as continuous variables and is capable of optimizing the number of turbines and their locations in the wind farm simultaneously. Two objectives are considered. One is to maximize the total power production, which is calculated by considering the wake effects using the Jensen wake model combined with the local wind distribution. The other is to minimize the total electrical cable length. This length is assumed to be the total length of the minimal spanning tree that connects all turbines and is calculated by using Prim's algorithm. Constraints on wind farm boundary and wind turbine proximity are also considered. An ideal test case shows the proposed algorithm largely outperforms a famous multi-objective genetic algorithm (NSGA-II). In the real test case based on the Horn Rev 1 wind farm, the algorithm also obtains useful Pareto frontiers and provides a wide range of Pareto optimal layouts with different numbers of turbines for a real-life wind farm developer.

Sandia SWiFT Wind Turbine Manual.

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, Jonathan; LeBlanc, Bruce Philip; Berg, Jonathan Charles

The Scaled Wind Farm Technology (SWiFT) facility, operated by Sandia National Laboratories for the U.S. Department of Energy's Wind and Water Power Program, is a wind energy research site with multiple wind turbines scaled for the experimental study of wake dynamics, advanced rotor development, turbine control, and advanced sensing for production-scale wind farms. The SWiFT site currently includes three variable-speed, pitch-regulated, three-bladed wind turbines. The six volumes of this manual provide a detailed description of the SWiFT wind turbines, including their operation and user interfaces, electrical and mechanical systems, assembly and commissioning procedures, and safety systems. Further dissemination only asmore » authorized to U.S. Government agencies and their contractors; other requests shall be approved by the originating facility or higher DOE programmatic authority. 111 UNCLASSIFIED UNLIMITED RELEASE Sandia SWiFT Wind Turbine Manual (SAND2016-0746 ) approved by: Department Manager SWiFT Site Lead Dave Minster (6121) Date Jonathan White (6121) Date SWiFT Site Supervisor Dave Mitchell (6121) Date Note: Document revision logs are found after the title page of each volume of this manual. iv« less

Three-dimensional structure of wind turbine wakes as measured by scanning lidar

NASA Astrophysics Data System (ADS)

Bodini, Nicola; Zardi, Dino; Lundquist, Julie K.

2017-08-01

The lower wind speeds and increased turbulence that are characteristic of turbine wakes have considerable consequences on large wind farms: turbines located downwind generate less power and experience increased turbulent loads. The structures of wakes and their downwind impacts are sensitive to wind speed and atmospheric variability. Wake characterization can provide important insights for turbine layout optimization in view of decreasing the cost of wind energy. The CWEX-13 field campaign, which took place between June and September 2013 in a wind farm in Iowa, was designed to explore the interaction of multiple wakes in a range of atmospheric stability conditions. Based on lidar wind measurements, we extend, present, and apply a quantitative algorithm to assess wake parameters such as the velocity deficits, the size of the wake boundaries, and the location of the wake centerlines. We focus on wakes from a row of four turbines at the leading edge of the wind farm to explore variations between wakes from the edge of the row (outer wakes) and those from turbines in the center of the row (inner wakes). Using multiple horizontal scans at different elevations, a three-dimensional structure of wakes from the row of turbines can be created. Wakes erode very quickly during unstable conditions and can in fact be detected primarily in stable conditions in the conditions measured here. During stable conditions, important differences emerge between the wakes of inner turbines and the wakes of outer turbines. Further, the strong wind veer associated with stable conditions results in a stretching of the wake structures, and this stretching manifests differently for inner and outer wakes. These insights can be incorporated into low-order wake models for wind farm layout optimization or for wind power forecasting.

Three-dimensional structure of wind turbine wakes as measured by scanning lidar

DOE PAGES

Bodini, Nicola; Zardi, Dino; Lundquist, Julie K.

2017-08-14

The lower wind speeds and increased turbulence that are characteristic of turbine wakes have considerable consequences on large wind farms: turbines located downwind generate less power and experience increased turbulent loads. The structures of wakes and their downwind impacts are sensitive to wind speed and atmospheric variability. Wake characterization can provide important insights for turbine layout optimization in view of decreasing the cost of wind energy. The CWEX-13 field campaign, which took place between June and September 2013 in a wind farm in Iowa, was designed to explore the interaction of multiple wakes in a range of atmospheric stability conditions.more » Based on lidar wind measurements, we extend, present, and apply a quantitative algorithm to assess wake parameters such as the velocity deficits, the size of the wake boundaries, and the location of the wake centerlines. We focus on wakes from a row of four turbines at the leading edge of the wind farm to explore variations between wakes from the edge of the row (outer wakes) and those from turbines in the center of the row (inner wakes). Using multiple horizontal scans at different elevations, a three-dimensional structure of wakes from the row of turbines can be created. Wakes erode very quickly during unstable conditions and can in fact be detected primarily in stable conditions in the conditions measured here. During stable conditions, important differences emerge between the wakes of inner turbines and the wakes of outer turbines. Further, the strong wind veer associated with stable conditions results in a stretching of the wake structures, and this stretching manifests differently for inner and outer wakes. As a result, these insights can be incorporated into low-order wake models for wind farm layout optimization or for wind power forecasting.« less

Active structural control of a floating wind turbine with a stroke-limited hybrid mass damper

NASA Astrophysics Data System (ADS)

Hu, Yaqi; He, Erming

2017-12-01

Floating wind turbines are subjected to more severe structural loads than fixed-bottom wind turbines due to additional degrees of freedom (DOFs) of their floating foundations. It's a promising way of using active structural control method to improve the structural responses of floating wind turbines. This paper investigates an active vibration control strategy for a barge-type floating wind turbine by setting a stroke-limited hybrid mass damper (HMD) in the turbine's nacelle. Firstly, a contact nonlinear modeling method for the floating wind turbine with clearance between the HMD and the stroke limiters is presented based on Euler-Lagrange's equations and an active control model of the whole system is established. The structural parameters are validated for the active control model and an equivalent load coefficient method is presented for identifying the wind and wave disturbances. Then, a state-feedback linear quadratic regulator (LQR) controller is designed to reduce vibration and loads of the wind turbine, and two optimization methods are combined to optimize the weighting coefficients when considering the stroke of the HMD and the active control power consumption as constraints. Finally, the designed controllers are implemented in high fidelity simulations under five typical wind and wave conditions. The results show that active HMD control strategy is shown to be achievable and the designed controllers could further reduce more vibration and loads of the wind turbine under the constraints of stroke limitation and power consumption. "V"-shaped distribution of the TMD suppression effect is inconsistent with the Weibull distribution in practical offshore floating wind farms, and the active HMD control could overcome this shortcoming of the passive TMD.

Three-dimensional structure of wind turbine wakes as measured by scanning lidar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bodini, Nicola; Zardi, Dino; Lundquist, Julie K.

The lower wind speeds and increased turbulence that are characteristic of turbine wakes have considerable consequences on large wind farms: turbines located downwind generate less power and experience increased turbulent loads. The structures of wakes and their downwind impacts are sensitive to wind speed and atmospheric variability. Wake characterization can provide important insights for turbine layout optimization in view of decreasing the cost of wind energy. The CWEX-13 field campaign, which took place between June and September 2013 in a wind farm in Iowa, was designed to explore the interaction of multiple wakes in a range of atmospheric stability conditions.more » Based on lidar wind measurements, we extend, present, and apply a quantitative algorithm to assess wake parameters such as the velocity deficits, the size of the wake boundaries, and the location of the wake centerlines. We focus on wakes from a row of four turbines at the leading edge of the wind farm to explore variations between wakes from the edge of the row (outer wakes) and those from turbines in the center of the row (inner wakes). Using multiple horizontal scans at different elevations, a three-dimensional structure of wakes from the row of turbines can be created. Wakes erode very quickly during unstable conditions and can in fact be detected primarily in stable conditions in the conditions measured here. During stable conditions, important differences emerge between the wakes of inner turbines and the wakes of outer turbines. Further, the strong wind veer associated with stable conditions results in a stretching of the wake structures, and this stretching manifests differently for inner and outer wakes. As a result, these insights can be incorporated into low-order wake models for wind farm layout optimization or for wind power forecasting.« less

Backup Mechanical Brake System of the Wind Turbine

NASA Astrophysics Data System (ADS)

Sirotkin, E. A.; Solomin, E. V.; Gandzha, S. A.; Kirpichnikova, I. M.

2018-01-01

Paper clarifies the necessity of the emergency mechanical brake systems usage for wind turbines. We made a deep analysis of the wind turbine braking methods available on the market, identifying their strengths and weaknesses. The electromechanical braking appeared the most technically reasonable and economically attractive. We described the developed combined electromechanical brake system for vertical axis wind turbine driven from electric drive with variable torque enough to brake over the turbine even on the storm wind speed up to 45 m/s. The progress was made due to the development of specific kinematic brake system diagram and intelligent control system managed by special operation algorithm.

Operation and Equivalent Loads of Wind Turbines in Large Wind Farms

NASA Astrophysics Data System (ADS)

Andersen, Soren Juhl; Sorensen, Jens Norkaer; Mikkelsen, Robert Flemming

2017-11-01

Wind farms continue to grow in size and as the technology matures, the design of wind farms move towards including dynamic effects besides merely annual power production estimates. The unsteady operation of wind turbines in large wind farms has been modelled with EllipSys3D(Michelsen, 1992, and Sørensen, 1995) for a number of different scenarios using a fully coupled large eddy simulations(LES) and aero-elastic framework. The turbines are represented in the flow fields using the actuator line method(Sørensen and Shen, 2002), where the aerodynamic forces and deflections are derived from an aero-elastic code, Flex5(Øye, 1996). The simulations constitute a database of full turbine operation in terms of both production and loads for various wind speeds, turbulence intensities, and turbine spacings. The operating conditions are examined in terms of averaged power production and thrust force, as well as 10min equivalent flapwise bending, yaw, and tilt moment loads. The analyses focus on how the performance and loads change throughout a given farm as well as comparing how various input parameters affect the operation and loads of the wind turbines during different scenarios. COMWIND(Grant 2104-09- 067216/DSF), Nordic Consortium on Optimization and Control of Wind Farms, Eurotech Greentech Wind project, Winds2Loads, and CCA LES. Ressources Granted on SNIC and JESS. The Vestas NM80 turbine has been used.

Spatial mapping and attribution of Wyoming wind turbines

USGS Publications Warehouse

O'Donnell, Michael S.; Fancher, Tammy S.

2010-01-01

This Wyoming wind-turbine data set represents locations of wind turbines found within Wyoming as of August 1, 2009. Each wind turbine is assigned to a wind farm. For each turbine, this report contains information about the following: potential megawatt output, rotor diameter, hub height, rotor height, land ownership, county, wind farm power capacity, the number of units currently associated with its wind farm, the wind turbine manufacturer and model, the wind farm developer, the owner of the wind farm, the current purchaser of power from the wind farm, the year the wind farm went online, and the status of its operation. Some attributes are estimates based on information that was obtained through the American Wind Energy Association and miscellaneous online reports. The locations are derived from August 2009 true-color aerial photographs made by the National Agriculture Imagery Program; the photographs have a positional accuracy of approximately ?5 meters. The location of wind turbines under construction during the development of this data set will likely be less accurate than the location of turbines already completed. The original purpose for developing the data presented here was to evaluate the effect of wind energy development on seasonal habitat used by greater sage-grouse. Additionally, these data will provide a planning tool for the Wyoming Landscape Conservation Initiative Science Team and for other wildlife- and habitat-related projects underway at the U.S. Geological Survey's Fort Collins Science Center. Specifically, these data will be used to quantify disturbance of the landscape related to wind energy as well as quantifying indirect disturbances to flora and fauna. This data set was developed for the 2010 project 'Seasonal predictive habitat models for greater sage-grouse in Wyoming.' This project's spatially explicit seasonal distribution models of sage-grouse in Wyoming will provide resource managers with tools for conservation planning. These specific data are being used for assessing the effect of disturbance resulting from wind energy development within Wyoming on sage-grouse populations.

Wind Turbine Wake Variability in a Large Wind Farm, Observed by Scanning Lidar

NASA Astrophysics Data System (ADS)

Lundquist, J. K.; Xiaoxia, G.; Aitken, M.; Quelet, P. T.; Rana, J.; Rhodes, M. E.; St Martin, C. M.; Tay, K.; Worsnop, R.; Irvin, S.; Rajewski, D. A.; Takle, E. S.

2014-12-01

Although wind turbine wake modeling is critical for accurate wind resource assessment, operational forecasting, and wind plant optimization, verification of such simulations is currently constrained by sparse datasets taken in limited atmospheric conditions, often of single turbines in isolation. To address this knowledge gap, our team deployed a WINDCUBE 200S scanning lidar in a 300-MW operating wind farm as part of the CWEX-13 field experiment. The lidar was deployed ~2000 m from a row of four turbines, such that wakes from multiple turbines could be sampled with horizontal scans. Twenty minutes of every hour were devoted to horizontal scans at ½ degree resolution at six different elevation angles. Twenty-five days of data were collected, with wind speeds at hub height ranging from quiescent to 14 m/s, and atmospheric stability varying from unstable to strongly stable. The example scan in Fig. 1a shows wakes from a row of four turbines propagating to the northwest. This extensive wake dataset is analyzed based on the quantitative approach of Aitken et al. (J. Atmos. Ocean. Technol. 2014), who developed an automated wake detection algorithm to characterize wind turbine wakes from scanning lidar data. We have extended the Aitken et al. (2014) method to consider multiple turbines in a single scan in order to classify the large numbers of wakes observed in the CWEX-13 dataset (Fig. 1b) during southerly flow conditions. The presentation will explore the variability of wake characteristics such as the velocity deficit and the wake width. These characteristics vary with atmospheric stability, atmospheric turbulence, and inflow wind speed. We find that the strongest and most persistent wakes occur at low to moderate wind speeds (region 2 of the turbine power curve) in stable conditions. We also present evidence that, in stable conditions with strong changes of wind direction with height, wakes propagate in different directions at different elevations above the surface. Finally, we compare characteristics of wakes at the outside of the row of turbines to wakes from turbines in the interior of the row, quantifying how wakes from outer turbines erode faster than those from interior.

76 FR 20006 - Wind Turbine Guidelines Advisory Committee; Teleconference Line Available for Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-11

...] Wind Turbine Guidelines Advisory Committee; Teleconference Line Available for Public Meeting AGENCY... Wildlife Service (Service), will host a Wind Turbine Guidelines Advisory Committee (Committee) meeting on... Service's Draft Land-Based Wind Energy Guidelines. DATES: The meeting will take place on April 27, 2011...

76 FR 38677 - Wind Turbine Guidelines Advisory Committee; Announcement of Public Meeting and Webcast

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-01

...] Wind Turbine Guidelines Advisory Committee; Announcement of Public Meeting and Webcast AGENCY: Fish and... Wildlife Service (Service), will host a Wind Turbine Guidelines Advisory Committee (Committee) meeting in... presentation and discussion of the Service's Draft Land-Based Wind Energy Guidelines. DATES: The meeting and...

76 FR 48174 - Wind Turbine Guidelines Advisory Committee; Announcement of Public Teleconference and Webcast

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-08

...] Wind Turbine Guidelines Advisory Committee; Announcement of Public Teleconference and Webcast AGENCY..., the U.S. Fish and Wildlife Service (Service), will host a Wind Turbine Guidelines Advisory Committee...-based wind energy facilities. All Committee members serve without compensation. In accordance with the...

Microgrid Control Strategy Utlizing Thermal Energy Storage With Renewable Solar And Wind Power Generation

DTIC Science & Technology

2016-06-01

13 Figure 6. Vertical Axis Wind Turbines and Photovoltaic Solar Panels ....................15 Figure 7. Solar Sunny Boy Inverter...16 Figure 8. Wind Turbine Inverters...1. Comparison of Energy Storage. Adapted from [16], [18], [19]. ................10 Table 2. DC Operating Voltage of Wind Turbine Inverters

76 FR 47353 - Final Directives for Forest Service Wind Energy Special Use Authorizations, Forest Service Manual...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-04

... siting wind energy turbines, evaluating a variety of resource interests, and addressing issues... power guidelines produced by the Wind Energy Turbines Guidelines Advisory Committee, which consists of... recognizes that recommendations from the Wind Energy Turbines Guidelines Advisory Committee will be used to...

76 FR 18238 - Wind Turbine Guidelines Advisory Committee; Announcement of Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-01

...] Wind Turbine Guidelines Advisory Committee; Announcement of Public Meeting AGENCY: Fish and Wildlife... (Service), will host a Wind Turbine Guidelines Advisory Committee (Committee) meeting on April 27, 2011... Turbine Guidelines Advisory Committee. [FR Doc. 2011-7788 Filed 3-31-11; 8:45 am] BILLING CODE 4310-55-P ...

The 200-kilowatt wind turbine project

NASA Technical Reports Server (NTRS)

1978-01-01

The three 200 kilowatt wind turbines described, compose the first of three separate systems. Proposed wind turbines of the two other systems, although similar in design, are larger in both physical size and rated power generation. The overall objective of the project is to obtain early operation and performance data while gaining initial experience in the operation of large, horizontal-axis wind turbines in typical utility environments. Several of the key issues addressed include the following: (1) impact of the variable power output (due to varying wind speeds) on the utility grid (2) compatibility with utility requirements (voltage and frequency control of generated power) (3) demonstration of unattended, fail-safe operation (4) reliability of the wind turbine system (5) required maintenance and (6) initial public reaction and acceptance.

Wind turbine remote control using Android devices

NASA Astrophysics Data System (ADS)

Rat, C. L.; Panoiu, M.

2018-01-01

This paper describes the remote control of a wind turbine system over the internet using an Android device, namely a tablet or a smartphone. The wind turbine workstation contains a LabVIEW program which monitors the entire wind turbine energy conversion system (WECS). The Android device connects to the LabVIEW application, working as a remote interface to the wind turbine. The communication between the devices needs to be secured because it takes place over the internet. Hence, the data are encrypted before being sent through the network. The scope was the design of remote control software capable of visualizing real-time wind turbine data through a secure connection. Since the WECS is fully automated and no full-time human operator exists, unattended access to the turbine workstation is needed. Therefore the device must not require any confirmation or permission from the computer operator in order to control it. Another condition is that Android application does not have any root requirements.

Numerical investigation of interactions between marine atmospheric boundary layer and offshore wind farm

NASA Astrophysics Data System (ADS)

Lyu, Pin; Chen, Wenli; Li, Hui; Shen, Lian

2017-11-01

In recent studies, Yang, Meneveau & Shen (Physics of Fluids, 2014; Renewable Energy, 2014) developed a hybrid numerical framework for simulation of offshore wind farm. The framework consists of simulation of nonlinear surface waves using a high-order spectral method, large-eddy simulation of wind turbulence on a wave-surface-fitted curvilinear grid, and an actuator disk model for wind turbines. In the present study, several more precise wind turbine models, including the actuator line model, actuator disk model with rotation, and nacelle model, are introduced into the computation. Besides offshore wind turbines on fixed piles, the new computational framework has the capability to investigate the interaction among wind, waves, and floating wind turbines. In this study, onshore, offshore fixed pile, and offshore floating wind farms are compared in terms of flow field statistics and wind turbine power extraction rate. The authors gratefully acknowledge financial support from China Scholarship Council (No. 201606120186) and the Institute on the Environment of University of Minnesota.

Investigation on wind turbine wakes: wind tunnel tests and field experiments with LIDARs

NASA Astrophysics Data System (ADS)

Iungo, Giacomo; Wu, Ting; Cöeffé, Juliette; Porté-Agel, Fernando; WIRE Team

2011-11-01

An investigation on the interaction between atmospheric boundary layer flow and wind turbines is carried out with wind tunnel and LIDAR measurements. The former were carried out using hot-wire anemometry and multi-hole pressure probes in the wake of a three-bladed miniature wind turbine. The wind turbine wake is characterized by a strong velocity defect in the proximity of the rotor, and its recovery is found to depend on the characteristics of the incoming atmospheric boundary layer (mean velocity and turbulence intensity profiles). Field experiments were performed using three wind LIDARs. Bi-dimensional scans are performed in order to analyse the wake wind field with different atmospheric boundary layer conditions. Furthermore, simultaneous measurements with two or three LIDARs allow the reconstruction of multi-component velocity fields. Both LIDAR and wind tunnel measurements highlight an increased turbulence level at the wake boundary for heights comparable to the top-tip of the blades; this flow feature can produce dangerous fatigue loads on following wind turbines.

Influence of omni-directional guide vane on the performance of cross-flow rotor for urban wind energy

NASA Astrophysics Data System (ADS)

Wicaksono, Yoga Arob; Tjahjana, Dominicus Danardono Dwi Prija; Hadi, Syamsul

2018-02-01

Vertical axis wind turbine like cross-flow rotor have some advantage there are, high self-starting torque, low noise, and high stability; so, it can be installed in the urban area to produce electricity. But, the urban area has poor wind condition, so the cross-flow rotor needs a guide vane to increase its performance. The aim of this study is to determine experimentally the effect of Omni-Directional Guide Vane (ODGV) on the performance of a cross-flow wind turbine. Wind tunnel experiment has been carried out for various configurations. The ODGV was placed around the cross-flow rotor in order to increase ambient wind environment of the wind turbine. The maximum power coefficient is obtained as Cpmax = 0.125 at 60° wind direction. It was 21.46% higher compared to cross-flow wind turbine without ODGV. This result showed that the ODGV able to increase the performance of the cross-flow wind turbine.

NREL Software Aids Offshore Wind Turbine Designs (Fact Sheet)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2013-10-01

NREL researchers are supporting offshore wind power development with computer models that allow detailed analyses of both fixed and floating offshore wind turbines. While existing computer-aided engineering (CAE) models can simulate the conditions and stresses that a land-based wind turbine experiences over its lifetime, offshore turbines require the additional considerations of variations in water depth, soil type, and wind and wave severity, which also necessitate the use of a variety of support-structure types. NREL's core wind CAE tool, FAST, models the additional effects of incident waves, sea currents, and the foundation dynamics of the support structures.

Numerical investigation of the optimum wind turbine sitting for domestic flat roofs

NASA Astrophysics Data System (ADS)

Ishfaq, Salman Muhammad; Chaudhry, Hassam Nasarullah

2018-05-01

The power capacity of roof mounted wind turbines is dependent on several factors which influence its energy yield. In this paper, an investigation has been carried out using Computational Fluid Dynamics (CFD) to determine flow distribution and establish an optimum mounting location for a small wind turbine on a domestic flat roof. The realisable k-ɛ and SST k-ω turbulence models were compared to establish their consistency with one another with respect to the physical domain. Nine mounting locations were considered for a pole mounted wind turbine. Three windward positions on the upwind side of the flat surfaced building were considered as viable locations for mounting the small wind turbine. Out of the three windward locations, the central upwind (1,0) mounting position was seen to be producing the highest velocity of 5.3 m/s from the available ambient velocity which was 4 m/s. Therefore, this mounting location provided the highest extractable power for the wind turbine. Conclusively, wind properties along with the mounting locations can play a significant role in either enhancing or diminishing the small wind turbine's performance on a domestic flat roof.

Effects of Offshore Wind Turbines on Ocean Waves

NASA Astrophysics Data System (ADS)

Wimer, Nicholas; Churchfield, Matthew; Hamlington, Peter

2014-11-01

Wakes from horizontal axis wind turbines create large downstream velocity deficits, thus reducing the available energy for downstream turbines while simultaneously increasing turbulent loading. Along with this deficit, however, comes a local increase in the velocity around the turbine rotor, resulting in increased surface wind speeds. For offshore turbines, these increased speeds can result in changes to the properties of wind-induced waves at the ocean surface. In this study, the characteristics and implications of such waves are explored by coupling a wave simulation code to the Simulator for Offshore Wind Farm Applications (SOWFA) developed by the National Renewable Energy Laboratory. The wave simulator and SOWFA are bi-directionally coupled using the surface wind field produced by an offshore wind farm to drive an ocean wave field, which is used to calculate a wave-dependent surface roughness that is fed back into SOWFA. The details of this combined framework are outlined. The potential for using the wave field created at offshore wind farms as an additional energy resource through the installation of on-site wave converters is discussed. Potential negative impacts of the turbine-induced wave field are also discussed, including increased oscillation of floating turbines.

Comparison of Three Methods for Wind Turbine Capacity Factor Estimation

PubMed Central

Ditkovich, Y.; Kuperman, A.

2014-01-01

Three approaches to calculating capacity factor of fixed speed wind turbines are reviewed and compared using a case study. The first “quasiexact” approach utilizes discrete wind raw data (in the histogram form) and manufacturer-provided turbine power curve (also in discrete form) to numerically calculate the capacity factor. On the other hand, the second “analytic” approach employs a continuous probability distribution function, fitted to the wind data as well as continuous turbine power curve, resulting from double polynomial fitting of manufacturer-provided power curve data. The latter approach, while being an approximation, can be solved analytically thus providing a valuable insight into aspects, affecting the capacity factor. Moreover, several other merits of wind turbine performance may be derived based on the analytical approach. The third “approximate” approach, valid in case of Rayleigh winds only, employs a nonlinear approximation of the capacity factor versus average wind speed curve, only requiring rated power and rotor diameter of the turbine. It is shown that the results obtained by employing the three approaches are very close, enforcing the validity of the analytically derived approximations, which may be used for wind turbine performance evaluation. PMID:24587755

Wind turbine rotor blade monitoring using digital image correlation: a comparison to aeroelastic simulations of a multi-megawatt wind turbine

NASA Astrophysics Data System (ADS)

Winstroth, J.; Schoen, L.; Ernst, B.; Seume, J. R.

2014-06-01

Optical full-field measurement methods such as Digital Image Correlation (DIC) provide a new opportunity for measuring deformations and vibrations with high spatial and temporal resolution. However, application to full-scale wind turbines is not trivial. Elaborate preparation of the experiment is vital and sophisticated post processing of the DIC results essential. In the present study, a rotor blade of a 3.2 MW wind turbine is equipped with a random black-and-white dot pattern at four different radial positions. Two cameras are located in front of the wind turbine and the response of the rotor blade is monitored using DIC for different turbine operations. In addition, a Light Detection and Ranging (LiDAR) system is used in order to measure the wind conditions. Wind fields are created based on the LiDAR measurements and used to perform aeroelastic simulations of the wind turbine by means of advanced multibody codes. The results from the optical DIC system appear plausible when checked against common and expected results. In addition, the comparison of relative out-ofplane blade deflections shows good agreement between DIC results and aeroelastic simulations.

Wind Turbines as Landscape Impediments to the Migratory Connectivity of Bats

USGS Publications Warehouse

Cryan, Paul M.

2011-01-01

Unprecedented numbers of migratory bats are found dead beneath industrial-scale wind turbines during late summer and autumn in both North America and Europe. Prior to the wide-scale deployment of wind turbines, fatal collisions of migratory bats with anthropogenic structures were rarely reported and likely occurred very infrequently. There are no other well-documented threats to populations of migratory tree bats that cause mortality of similar magnitude to that observed at wind turbines. Just three migratory species comprise the vast majority of bat kills at turbines in North America and there are indications that turbines may actually attract migrating individuals toward their blades. Although fatality of certain migratory species is consistent in occurrence across large geographic regions, fatality rates differ across sites for reasons mostly unknown. Cumulative fatality for turbines in North America might already range into the hundreds of thousands of bats per year. Research into the causes of bat fatalities at wind turbines can ascertain the scale of the problem and help identify solutions. None of the migratory bats known to be most affected by wind turbines are protected by conservation laws, nor is there a legal mandate driving research into the problem or implementation of potential solutions.

Experimental investigations on the aerodynamics and aeromechanics of wind turbines for floating offshore applications

NASA Astrophysics Data System (ADS)

Khosravi, Morteza

There are many advantages in floating wind turbines in deep waters, however, there are also significant technological challenges associated with it too. The dynamic excitation of wind and waves can induce excessive motions along each of the 6 degrees of freedom (6-DOF) of the floating platforms. These motions will then be transferred to the turbine, and directly impact the wake characteristics of the floating wind turbines, and consequently the resultant wind loadings and performances of the wind turbines sited in offshore wind farms. In the present study, a comprehensive experimental study was performed to analyze the performance, loading, and the near wake characteristics of a rigid wind turbine model subjected to surge, heave, and pitch motions. The experimental study was performed in a large-scale atmospheric boundary layer wind tunnel with a scaled three-blade Horizontal Axial Wind Turbine model placed in a turbulent boundary layer airflow with similar mean and turbulence characteristics as those over a typical offshore wind farm. The base of the 1:300 scaled model wind turbine was mounted on translation and rotation stages. These stages can be controlled to generate surge, pitch and heave motions to simulate the dynamic motions experienced by floating offshore wind turbines. During the experiments, the velocity scaling method was chosen to maintain the similar velocity ratios (i.e., the ratios of the incoming airflow flow to that of turbine base motion) between the model and the prototype. During the experiments, a high resolution digital particle image velocimetry (PIV) system was used to achieve flow field measurements to quantify the characteristics of the turbulent vortex flow in the near wake of the wind turbine model. Besides conducting ''free run'' PIV measurements to determine the ensemble-averaged statistics of the flow quantities such as mean velocity, Reynolds stress, and turbulence kinetic energy (TKE) distributions in the wake flow, ''phase-locked'' PIV measurements were also performed to elucidate further details about evolution of the unsteady vortex structures in the wake flow in relation to the position of the rotating turbine blades. The effects of the surge, heave, and pitch motions of the wind turbine base on the wake flow characteristics were examined in great details based on the PIV measurements. The findings derived from the present study can be used to improve the understanding of the underlying physics for optimal mechanical design of floating offshore wind turbines, as well as the layout optimization of floating offshore wind farms. Although, the mean power measurement results show little difference between the oscillating turbine and the bottom fixed turbine, but the excessive fluctuations in the power output of the oscillating turbine is anticipated to greatly reduce the power quality of such floating turbines. The load measurements also show substantial amount of difference both in terms of mean and the fluctuating components. The results of the wake study reveal that the wake of a wind turbine subjected to base motions, is highly dependent on which direction the turbine is oscillating. In the case of the moving turbine, the wake accelerates as the turbine is moving with the flow, hence, reducing the power extraction by the turbine. A decrease in Reynolds shear stress and the turbulent kinetic energy production was noted as the turbine was oscillating with the flow. However, as the turbine was moving into the flow, these effects reverse, and causes a deceleration in the wake of the moving turbine, hence increases the power production by the turbine, and increase the Reynolds shear stress and the turbulent kinetic energy. Finally, The wake flow field (x/D < 2.5) measurements behind a two-bladed Darrieus type VAWT were also carried out by using a high-resolution PIV system, and the results obtained at two different horizontal (x-y) planes, at the equator height (H/2) and above the equator height (3H/4), for four different tip speed ratios (lambda = 2, 2.5, 3 and 3.5) of the VAWT were then evaluated and compared. The wake of the VAWT is found to be significantly different to that of the HAWT's. At lower tip-speed-ratio (i.e. TSR 2) the wake tends to be very asymmetric and skewed with relatively higher amount of momentum in the wake in comparison to higher tip-speed ratios (i.e. 3 or 3.5). As tip-speed ratio increases, there is a tendency in flow stagnation in the wake and eventually flow reversal would occur at higher tip-speed-ratios. The wake dynamics (i.e., the instabilities inherent in VAWT) behind the VAWTs would lead to a much faster wake recovery in comparison to the HAWTs.

Optimizing wind farm layout via LES-calibrated geometric models inclusive of wind direction and atmospheric stability effects

NASA Astrophysics Data System (ADS)

Archer, Cristina; Ghaisas, Niranjan

2015-04-01

The energy generation at a wind farm is controlled primarily by the average wind speed at hub height. However, two other factors impact wind farm performance: 1) the layout of the wind turbines, in terms of spacing between turbines along and across the prevailing wind direction; staggering or aligning consecutive rows; angles between rows, columns, and prevailing wind direction); and 2) atmospheric stability, which is a measure of whether vertical motion is enhanced (unstable), suppressed (stable), or neither (neutral). Studying both factors and their complex interplay with Large-Eddy Simulation (LES) is a valid approach because it produces high-resolution, 3D, turbulent fields, such as wind velocity, temperature, and momentum and heat fluxes, and it properly accounts for the interactions between wind turbine blades and the surrounding atmospheric and near-surface properties. However, LES are computationally expensive and simulating all the possible combinations of wind directions, atmospheric stabilities, and turbine layouts to identify the optimal wind farm configuration is practically unfeasible today. A new, geometry-based method is proposed that is computationally inexpensive and that combines simple geometric quantities with a minimal number of LES simulations to identify the optimal wind turbine layout, taking into account not only the actual frequency distribution of wind directions (i.e., wind rose) at the site of interest, but also atmospheric stability. The geometry-based method is calibrated with LES of the Lillgrund wind farm conducted with the Software for Offshore/onshore Wind Farm Applications (SOWFA), based on the open-access OpenFOAM libraries. The geometric quantities that offer the best correlations (>0.93) with the LES results are the blockage ratio, defined as the fraction of the swept area of a wind turbine that is blocked by an upstream turbine, and the blockage distance, the weighted distance from a given turbine to all upstream turbines that can potentially block it. Based on blockage ratio and distance, an optimization procedure is proposed that explores many different layout variables and identifies, given actual wind direction and stability distributions, the optimal wind farm layout, i.e., the one with the highest wind energy production. The optimization procedure is applied to both the calibration wind farm (Lillgrund) and a test wind farm (Horns Rev) and a number of layouts more efficient than the existing ones are identified. The optimization procedure based on geometric models proposed here can be applied very quickly (within a few hours) to any proposed wind farm, once enough information on wind direction frequency and, if available, atmospheric stability frequency has been gathered and once the number of turbines and/or the areal extent of the wind farm have been identified.

Wind Power Generation Design Considerations.

DTIC Science & Technology

1984-12-01

DISTRIBUTION 4 I o ....................................... . . . e . * * TABLES Number Page I Wind Turbine Characteristics II 0- 2 Maximum Economic Life II 3...Ratio of Blade Tip Speed to Wind Speed 10 4 Interference with Microwave and TV Reception by Wind Turbines 13 5 Typical Flow Patterns Over Two...18 * 12 Annual Mean Wind Power Density 21 5 FIGURES (Cont’d) Number Page 13 Wind - Turbine /Generator Types Currently Being Tested on Utility Sites 22 14

Western Wind Data Set | Grid Modernization | NREL

Science.gov Websites

replicates the stochastic nature of wind power plant output. NREL modeled hysteresis around wind turbine cut where wind speeds are often near wind turbine cut-out (~25 m/s), SCORE output does not replicate the Vestas V90). The hysteresis-corrected SCORE is an attempt to put the wind turbine hysteresis at cut-out

Wind Energy | Climate Neutral Research Campuses | NREL

Science.gov Websites

turbine or wind farm is one of the few technologies that supplies renewable energy at the scale required . Before determining whether a site is suitable for a wind turbine, read the Wind Energy Siting Handbook Community College has installed a wind turbine on site and now offers an Associate Degree in wind energy and

Eastern Wind Data Set | Grid Modernization | NREL

Science.gov Websites

cell was computed by combining these data sets with a composite turbine power curve. Wind power plants wind speed at the site. Adjustments were made for model biases, wake losses, wind gusts, turbine and conversion was also updated to better reflect future wind turbine technology. The 12-hour discontinuity was

78 FR 44150 - Atlantic Wind Lease Sale 1 (ATLW1) Commercial Leasing for Wind Power on the Outer Continental...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-23

... for the siting of two 6-megawatt (MW) wind turbines for demonstration and research purposes. The... the maximum rated electric output, expressed in MW, which the turbines of the wind farm facility under commercial operations can produce at their rated wind speed as designated by the turbine's manufacturer. The...

Investigation of the Impact of the Upstream Induction Zone on LIDAR Measurement Accuracy for Wind Turbine Control Applications using Large-Eddy Simulation

NASA Astrophysics Data System (ADS)

Simley, Eric; Y Pao, Lucy; Gebraad, Pieter; Churchfield, Matthew

2014-06-01

Several sources of error exist in lidar measurements for feedforward control of wind turbines including the ability to detect only radial velocities, spatial averaging, and wind evolution. This paper investigates another potential source of error: the upstream induction zone. The induction zone can directly affect lidar measurements and presents an opportunity for further decorrelation between upstream wind and the wind that interacts with the rotor. The impact of the induction zone is investigated using the combined CFD and aeroelastic code SOWFA. Lidar measurements are simulated upstream of a 5 MW turbine rotor and the true wind disturbances are found using a wind speed estimator and turbine outputs. Lidar performance in the absence of an induction zone is determined by simulating lidar measurements and the turbine response using the aeroelastic code FAST with wind inputs taken far upstream of the original turbine location in the SOWFA wind field. Results indicate that while measurement quality strongly depends on the amount of wind evolution, the induction zone has little effect. However, the optimal lidar preview distance and circular scan radius change slightly due to the presence of the induction zone.

Analysis of Control-Oriented Wake Modeling Tools Using Lidar Field Results

DOE PAGES

Annoni, Jennifer; Fleming, Paul; Scholbrock, Andrew; ...

2018-02-08

Wind turbines in a wind farm operate individually to maximize their own performance regardless of the impact of aerodynamic interactions on neighboring turbines. Wind farm controls can be used to increase power production or reduce overall structural loads by properly coordinating turbines. One wind farm control strategy that is addressed in literature is known as wake steering, wherein upstream turbines operate in yaw misaligned conditions to redirect their wakes away from downstream turbines. The National Renewable Energy Laboratory (NREL) in Golden, CO conducted a demonstration of wake steering on a single utility-scale turbine. In this study, the turbine was operatedmore » at various yaw misalignment setpoints while a lidar mounted on the nacelle scanned five downstream distances. The lidar measurements were combined with turbine data, as well as measurements of the inflow made by a highly instrumented meteorological mast upstream. The full-scale measurements are used to validate controls-oriented tools, including wind turbine wake models, used for wind farm controls and optimization. This paper presents a quantitative comparison of the lidar data and controls-oriented wake models under different atmospheric conditions and turbine operation. The results show good agreement between the lidar data and the models under these different conditions.« less

Analysis of Control-Oriented Wake Modeling Tools Using Lidar Field Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Annoni, Jennifer; Fleming, Paul; Scholbrock, Andrew

Wind turbines in a wind farm operate individually to maximize their own performance regardless of the impact of aerodynamic interactions on neighboring turbines. Wind farm controls can be used to increase power production or reduce overall structural loads by properly coordinating turbines. One wind farm control strategy that is addressed in literature is known as wake steering, wherein upstream turbines operate in yaw misaligned conditions to redirect their wakes away from downstream turbines. The National Renewable Energy Laboratory (NREL) in Golden, CO conducted a demonstration of wake steering on a single utility-scale turbine. In this study, the turbine was operatedmore » at various yaw misalignment setpoints while a lidar mounted on the nacelle scanned five downstream distances. The lidar measurements were combined with turbine data, as well as measurements of the inflow made by a highly instrumented meteorological mast upstream. The full-scale measurements are used to validate controls-oriented tools, including wind turbine wake models, used for wind farm controls and optimization. This paper presents a quantitative comparison of the lidar data and controls-oriented wake models under different atmospheric conditions and turbine operation. The results show good agreement between the lidar data and the models under these different conditions.« less

Advanced Control Design for Wind Turbines; Part I: Control Design, Implementation, and Initial Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wright, A. D.; Fingersh, L. J.

The purpose of this report is to give wind turbine engineers information and examples of the design, testing through simulation, field implementation, and field testing of advanced wind turbine controls.

Toward Development of a Stochastic Wake Model: Validation Using LES and Turbine Loads

DOE PAGES

Moon, Jae; Manuel, Lance; Churchfield, Matthew; ...

2017-12-28

Wind turbines within an array do not experience free-stream undisturbed flow fields. Rather, the flow fields on internal turbines are influenced by wakes generated by upwind unit and exhibit different dynamic characteristics relative to the free stream. The International Electrotechnical Commission (IEC) standard 61400-1 for the design of wind turbines only considers a deterministic wake model for the design of a wind plant. This study is focused on the development of a stochastic model for waked wind fields. First, high-fidelity physics-based waked wind velocity fields are generated using Large-Eddy Simulation (LES). Stochastic characteristics of these LES waked wind velocity field,more » including mean and turbulence components, are analyzed. Wake-related mean and turbulence field-related parameters are then estimated for use with a stochastic model, using Multivariate Multiple Linear Regression (MMLR) with the LES data. To validate the simulated wind fields based on the stochastic model, wind turbine tower and blade loads are generated using aeroelastic simulation for utility-scale wind turbine models and compared with those based directly on the LES inflow. The study's overall objective is to offer efficient and validated stochastic approaches that are computationally tractable for assessing the performance and loads of turbines operating in wakes.« less

Toward Development of a Stochastic Wake Model: Validation Using LES and Turbine Loads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moon, Jae; Manuel, Lance; Churchfield, Matthew

Wind turbines within an array do not experience free-stream undisturbed flow fields. Rather, the flow fields on internal turbines are influenced by wakes generated by upwind unit and exhibit different dynamic characteristics relative to the free stream. The International Electrotechnical Commission (IEC) standard 61400-1 for the design of wind turbines only considers a deterministic wake model for the design of a wind plant. This study is focused on the development of a stochastic model for waked wind fields. First, high-fidelity physics-based waked wind velocity fields are generated using Large-Eddy Simulation (LES). Stochastic characteristics of these LES waked wind velocity field,more » including mean and turbulence components, are analyzed. Wake-related mean and turbulence field-related parameters are then estimated for use with a stochastic model, using Multivariate Multiple Linear Regression (MMLR) with the LES data. To validate the simulated wind fields based on the stochastic model, wind turbine tower and blade loads are generated using aeroelastic simulation for utility-scale wind turbine models and compared with those based directly on the LES inflow. The study's overall objective is to offer efficient and validated stochastic approaches that are computationally tractable for assessing the performance and loads of turbines operating in wakes.« less

Methods and apparatus for twist bend coupled (TCB) wind turbine blades

DOEpatents

Moroz, Emilian Mieczyslaw; LeMieux, David Lawrence; Pierce, Kirk Gee

2006-10-10

A method for controlling a wind turbine having twist bend coupled rotor blades on a rotor mechanically coupled to a generator includes determining a speed of a rotor blade tip of the wind turbine, measuring a current twist distribution and current blade loading, and adjusting a torque of a generator to change the speed of the rotor blade tip to thereby increase an energy capture power coefficient of the wind turbine.

Flow Over a Body of Revolution in a Steady Turn

DTIC Science & Technology

2004-10-01

31], Migliore and Wolfe [32]. Migliore investigated flow curvature effects on Darrieus wind turbines , a special type of turbine which has a continuous...and Wolfe- J. B.. Some Effects of Flow Curvature Effects oil the Aerodynamics of Darrieus Wind Turbines West Viryinia University , 1979 33. Hirsch, Ch...and Mandal. A. C., Flow Curvature Effects on Vertical Axis Darrieus Wind Turbine Having High Chord-Radius Ratio European Wind Energy Confer- ence

7 CFR Appendix A to Subpart B of... - Technical Reports for Projects With Total Eligible Project Costs of $200,000 or Less

Code of Federal Regulations, 2012 CFR

2012-01-01

... of the wind turbine is 100kW or smaller and with a generator hub height of 120 feet or less. Small... demonstrate the amount of local wind resource where the small wind turbine is to be installed. Indicate the... of the individual wind turbine(s) is larger than 100kW. (a) Qualifications of key project service...

7 CFR Appendix A to Subpart B of... - Technical Reports for Projects With Total Eligible Project Costs of $200,000 or Less

Code of Federal Regulations, 2013 CFR

2013-01-01

... of the wind turbine is 100kW or smaller and with a generator hub height of 120 feet or less. Small... demonstrate the amount of local wind resource where the small wind turbine is to be installed. Indicate the... of the individual wind turbine(s) is larger than 100kW. (a) Qualifications of key project service...

7 CFR Appendix A to Subpart B of... - Technical Reports for Projects With Total Eligible Project Costs of $200,000 or Less

Code of Federal Regulations, 2014 CFR

2014-01-01

... of the wind turbine is 100kW or smaller and with a generator hub height of 120 feet or less. Small... demonstrate the amount of local wind resource where the small wind turbine is to be installed. Indicate the... of the individual wind turbine(s) is larger than 100kW. (a) Qualifications of key project service...

Calculation of Transient Potential Rise on the Wind Turbine Struck by Lightning

PubMed Central

Xiaoqing, Zhang

2014-01-01

A circuit model is proposed in this paper for calculating the transient potential rise on the wind turbine struck by lightning. The model integrates the blade, sliding contact site, and tower and grounding system of the wind turbine into an equivalent circuit. The lightning current path from the attachment point to the ground can be fully described by the equivalent circuit. The transient potential responses are obtained in the different positions on the wind turbine by solving the circuit equations. In order to check the validity of the model, the laboratory measurement is made with a reduced-scale wind turbine. The measured potential waveform is compared with the calculated one and a better agreement is shown between them. The practical applicability of the model is also examined by a numerical example of a 2 MW Chinese-built wind turbine. PMID:25254231

'Wind turbine syndrome': fact or fiction?

PubMed

Farboud, A; Crunkhorn, R; Trinidade, A

2013-03-01

Symptoms, including tinnitus, ear pain and vertigo, have been reported following exposure to wind turbine noise. This review addresses the effects of infrasound and low frequency noise and questions the existence of 'wind turbine syndrome'. This review is based on a search for articles published within the last 10 years, conducted using the PubMed database and Google Scholar search engine, which included in their title or abstract the terms 'wind turbine', 'infrasound' or 'low frequency noise'. There is evidence that infrasound has a physiological effect on the ear. Until this effect is fully understood, it is impossible to conclude that wind turbine noise does not cause any of the symptoms described. However, many believe that these symptoms are related largely to the stress caused by unwanted noise exposure. There is some evidence of symptoms in patients exposed to wind turbine noise. The effects of infrasound require further investigation.

Wind turbines: is there a human health risk?

PubMed

Roberts, Jennifer D; Roberts, Mark A

2013-04-01

The term "Wind Turbine Syndrome" was coined in a recently self-published book, which hypothesized that a multitude of symptoms such as headache and dizziness resulted from wind turbines generating low frequency sound (LFS). The objective of this article is to provide a summary of the peer-reviewed literature on the research that has examined the relationship between human health effects and exposure to LFS and sound generated from the operation of wind turbines. At present, a specific health condition has not been documented in the peer-reviewed literature that has been classified as a disease caused by exposure to sound levels and frequencies generated by the operation of wind turbines. Communities are experiencing a heightened sense of annoyance and fear from the development and siting of wind turbine farms. High-quality research and effective risk communication can advance this course from one of panic to one of understanding and exemplification for other environmental advancements.

Assessing Fatigue and Ultimate Load Uncertainty in Floating Offshore Wind Turbines Due to Varying Simulation Length

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stewart, G.; Lackner, M.; Haid, L.

2013-07-01

With the push towards siting wind turbines farther offshore due to higher wind quality and less visibility, floating offshore wind turbines, which can be located in deep water, are becoming an economically attractive option. The International Electrotechnical Commission's (IEC) 61400-3 design standard covers fixed-bottom offshore wind turbines, but there are a number of new research questions that need to be answered to modify these standards so that they are applicable to floating wind turbines. One issue is the appropriate simulation length needed for floating turbines. This paper will discuss the results from a study assessing the impact of simulation lengthmore » on the ultimate and fatigue loads of the structure, and will address uncertainties associated with changing the simulation length for the analyzed floating platform. Recommendations of required simulation length based on load uncertainty will be made and compared to current simulation length requirements.« less

Detecting salt deposition on a wind turbine blade using laser induced breakdown spectroscopy technique

NASA Astrophysics Data System (ADS)

Sathiesh Kumar, V.; Vasa, Nilesh J.; Sarathi, R.

2013-07-01

The study of pollution performance on a wind turbine blade due to lightning is important, as it can cause major damage to wind turbine blades. In the present work, optical emission spectroscopy (OES) technique is used to understand the influence of pollutant deposited on a wind turbine blade in an off-shore environment. A methodical experimental study was carried out by adopting IEC 60507 standards, and it was observed that the lightning discharge propagates at the interface between the pollutant and the glass fiber reinforced plastic (Material used in manufacturing of wind turbine blades). In addition, as a diagnostic condition monitoring technique, laser-induced breakdown spectroscopy (LIBS) is proposed and demonstrated to rank the severity of pollutant on the wind turbine blades from a remote area. Optical emission spectra observed during surface discharge process induced by lightning impulse voltage is in agreement with the spectra observed during LIBS.

EDITORIAL: Wind energy

NASA Astrophysics Data System (ADS)

Mann, Jakob; Nørkær Sørensen, Jens; Morthorst, Poul-Erik

2008-01-01

Wind energy is rapidly growing. In 2006 the installed generating capacity in the world increased by 25%, a growth rate which has more or less been sustained during the last decade. And there is no reason to believe that this growth will slow significantly in the coming years. For example, the United Kingdom's goal for installed wind turbines by 2020 is 33 GW up from 2 GW in 2006, an average annual growth rate of 22% over that period. More than half of all turbines are installed in Europe, but United States, India and lately China are also rapidly growing markets. The cradle of modern wind energy was set by innovative blacksmiths in rural Denmark. Now the wind provides more than 20% of the electrical power in Denmark, the industry has professionalized and has close ties with public research at universities. This focus issue is concerned with research in wind energy. The main purposes of research in wind energy are to: decrease the cost of power generated by the wind; increase the reliability and predictability of the energy source; investigate and reduce the adverse environmental impact of massive deployment of wind turbines; build research based educations for wind energy engineers. This focus issue contains contributions from several fields of research. Decreased costs cover a very wide range of activities from aerodynamics of the wind turbine blades, optimal site selection for the turbines, optimization of the electrical grid and power market for a fluctuating source, more efficient electrical generators and gears, and new materials and production techniques for turbine manufacturing. The United Kingdom recently started the construction of the London Array, a 1 GW off-shore wind farm east of London consisting of several hundred turbines. To design such a farm optimally it is necessary to understand the chaotic and very turbulent flow downwind from a turbine, which decreases the power production and increases the mechanical loads on other nearby turbines. Also addressed within the issue is how much conventional power production can be replaced by the ceaseless wind, with the question of how Greece's target of 29% renewables by 2020 is to be met efficiently. Other topics include an innovative way to determine the power curve of a turbine experimentally more accurately, the use of fluid dynamics tools to investigate the implications of placing vortex generators on wind turbine blades (thereby possibly improving their efficiency) and a study of the perception of wind turbine noise. It turns out that a small but significant fraction of wind turbine neighbours feel that turbine generated noise impairs their ability to rest. The annoyance is correlated with a negative attitude towards the visual impact on the landscape, but what is cause and effect is too early to say. As mentioned there is a rush for wind turbines in many countries. However, this positive development for the global climate is currently limited by practical barriers. One bottleneck is the difficulties for the sub-suppliers of gears and other parts to meet the demand. Another is the difficulties to meet the demand for engineers specialized in wind. For that reason the Technical University of Denmark (DTU) recently launched the world's first Wind Energy Masters Program. Here and elsewhere in the world of wind education and research we should really speed up now, as our chances of contributing to emission free energy production and a healthier global climate have never been better. Focus on Wind Energy Contents The articles below represent the first accepted contributions and further additions will appear in the near future. Wind turbines—low level noise sources interfering with restoration? Eja Pedersen and Kerstin Persson Waye On the effect of spatial dispersion of wind power plants on the wind energy capacity credit in Greece George Caralis, Yiannis Perivolaris, Konstantinos Rados and Arthouros Zervos Large-eddy simulation of spectral coherence in a wind turbine wake A Jimenez, A Crespo, E Migoya and J Garcia How to improve the estimation of power curves for wind turbines Julia Gottschall and Joachim Peinke

Performance Investigation of A Mix Wind Turbine Using A Clutch Mechanism At Low Wind Speed Condition

NASA Astrophysics Data System (ADS)

Jamanun, M. J.; Misaran, M. S.; Rahman, M.; Muzammil, W. K.

2017-07-01

Wind energy is one of the methods that generates energy from sustainable resources. This technology has gained prominence in this era because it produces no harmful product to the society. There is two fundamental type of wind turbine are generally used this day which is Horizontal axis wind turbine (HAWT) and Vertical axis wind turbine (VAWT). The VAWT technology is more preferable compare to HAWT because it gives better efficiency and cost effectiveness as a whole. However, VAWT is known to have distinct disadvantage compared to HAWT; self-start ability and efficiency at low wind speed condition. Different solution has been proposed to solve these issues which includes custom design blades, variable angle of attack mechanism and mix wind turbine. A new type of clutch device was successfully developed in UMS to be used in a mix Savonius-Darrieus wind turbine configuration. The clutch system which barely audible when in operation compared to a ratchet clutch system interconnects the Savonius and Darrieus rotor; allowing the turbine to self-start at low wind speed condition as opposed to a standalone Darrieus turbine. The Savonius height were varied at three different size in order to understand the effect of the Savonius rotor to the mix wind turbine performance. The experimental result shows that the fabricated Savonius rotor show that the height of the Savonius rotor affecting the RPM for the turbine. The swept area (SA), aspect ratio (AR) and tip speed ratio (TSR) also calculated in this paper. The highest RPM recorded in this study is 90 RPM for Savonius rotor 0.22-meter height at 2.75 m/s. The Savonius rotor 0.22-meter also give the highest TSR for each range of speed from 0.75 m/s, 1.75 m/s and 2.75 m/s where it gives 1.03 TSR, 0.76 TSR, and 0.55 TSR.

Shear and Turbulence Estimates for Calculation of Wind Turbine Loads and Responses Under Hurricane Strength Winds

NASA Astrophysics Data System (ADS)

Kosovic, B.; Bryan, G. H.; Haupt, S. E.

2012-12-01

Schwartz et al. (2010) recently reported that the total gross energy-generating offshore wind resource in the United States in waters less than 30m deep is approximately 1000 GW. Estimated offshore generating capacity is thus equivalent to the current generating capacity in the United States. Offshore wind power can therefore play important role in electricity production in the United States. However, most of this resource is located along the East Coast of the United States and in the Gulf of Mexico, areas frequently affected by tropical cyclones including hurricanes. Hurricane strength winds, associated shear and turbulence can affect performance and structural integrity of wind turbines. In a recent study Rose et al. (2012) attempted to estimate the risk to offshore wind turbines from hurricane strength winds over a lifetime of a wind farm (i.e. 20 years). According to Rose et al. turbine tower buckling has been observed in typhoons. They concluded that there is "substantial risk that Category 3 and higher hurricanes can destroy half or more of the turbines at some locations." More robust designs including appropriate controls can mitigate the risk of wind turbine damage. To develop such designs good estimates of turbine loads under hurricane strength winds are essential. We use output from a large-eddy simulation of a hurricane to estimate shear and turbulence intensity over first couple of hundred meters above sea surface. We compute power spectra of three velocity components at several distances from the eye of the hurricane. Based on these spectra analytical spectral forms are developed and included in TurbSim, a stochastic inflow turbulence code developed by the National Renewable Energy Laboratory (NREL, http://wind.nrel.gov/designcodes/preprocessors/turbsim/). TurbSim provides a numerical simulation including bursts of coherent turbulence associated with organized turbulent structures. It can generate realistic flow conditions that an operating turbine would encounter under hurricane strength winds. These flow fields can be used to estimate wind turbine loads and responses with AeroDyn (http://wind.nrel.gov/designcodes/simulators/aerodyn/) and FAST (http://wind.nrel.gov/designcodes/simulators/fast/) codes also developed by NREL.

Gradient-Based Optimization of Wind Farms with Different Turbine Heights: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stanley, Andrew P. J.; Thomas, Jared; Ning, Andrew

Turbine wakes reduce power production in a wind farm. Current wind farms are generally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy (COE) may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the COE of a wind farm through layout optimization and varying turbine hubmore » heights. Results indicate that when a farm is optimized for layout and height with two separate height groups, COE can be lowered by as much as 5%-9%, compared to a similar layout and height optimization where all the towers are the same. The COE has the best improvement in farms with high turbine density and a low wind shear exponent.« less

Gradient-Based Optimization of Wind Farms with Different Turbine Heights

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stanley, Andrew P. J.; Thomas, Jared; Ning, Andrew

Turbine wakes reduce power production in a wind farm. Current wind farms are generally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy (COE) may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the COE of a wind farm through layout optimization and varying turbine hubmore » heights. Results indicate that when a farm is optimized for layout and height with two separate height groups, COE can be lowered by as much as 5%-9%, compared to a similar layout and height optimization where all the towers are the same. The COE has the best improvement in farms with high turbine density and a low wind shear exponent.« less

Optimal sensor placement for modal testing on wind turbines

NASA Astrophysics Data System (ADS)

Schulze, Andreas; Zierath, János; Rosenow, Sven-Erik; Bockhahn, Reik; Rachholz, Roman; Woernle, Christoph

2016-09-01

The mechanical design of wind turbines requires a profound understanding of the dynamic behaviour. Even though highly detailed simulation models are already in use to support wind turbine design, modal testing on a real prototype is irreplaceable to identify site-specific conditions such as the stiffness of the tower foundation. Correct identification of the mode shapes of a complex mechanical structure much depends on the placement of the sensors. For operational modal analysis of a 3 MW wind turbine with a 120 m rotor on a 100 m tower developed by W2E Wind to Energy, algorithms for optimal placement of acceleration sensors are applied. The mode shapes used for the optimisation are calculated by means of a detailed flexible multibody model of the wind turbine. Among the three algorithms in this study, the genetic algorithm with weighted off-diagonal criterion yields the sensor configuration with the highest quality. The ongoing measurements on the prototype will be the basis for the development of optimised wind turbine designs.

Stall behavior of a scaled three-dimensional wind turbine blade

NASA Astrophysics Data System (ADS)

Mulleners, Karen; Melius, Matthew; Cal, Raul Bayoan

2014-11-01

The power generation of a wind turbine is influenced by many factors including the unsteady incoming flow characteristics, pitch regulation, and the geometry of the various turbine components. Within the framework of maximizing energy extraction, it is important to understand and tailor the aerodynamics of a wind turbine. In the interest of seeking further understanding into the complex flow over wind turbine blades, a three-dimensional scaled blade model has been designed and manufactured to be dynamically similar to a rotating full-scale NREL 5MW wind turbine blade. A wind tunnel experiment has been carried out in the 2.2 m × 1.8 m cross-section closed loop wind tunnel at DLR in Göttingen by means of time-resolved stereoscopic PIV. An extensive coherent structure analysis of the time-resolved velocity field over the suction side of the blade was performed to study stall characteristics under a geometrically induced pressure gradient. In particular, the radial extent and propagation of stalled flow regions were characterized for various static angles of attack.

Health-Based Audible Noise Guidelines Account for Infrasound and Low-Frequency Noise Produced by Wind Turbines

PubMed Central

Berger, Robert G.; Ashtiani, Payam; Ollson, Christopher A.; Whitfield Aslund, Melissa; McCallum, Lindsay C.; Leventhall, Geoff; Knopper, Loren D.

2015-01-01

Setbacks for wind turbines have been established in many jurisdictions to address potential health concerns associated with audible noise. However, in recent years, it has been suggested that infrasound (IS) and low-frequency noise (LFN) could be responsible for the onset of adverse health effects self-reported by some individuals living in proximity to wind turbines, even when audible noise limits are met. The purpose of this paper was to investigate whether current audible noise-based guidelines for wind turbines account for the protection of human health, given the levels of IS and LFN typically produced by wind turbines. New field measurements of indoor IS and outdoor LFN at locations between 400 and 900 m from the nearest turbine, which were previously underrepresented in the scientific literature, are reported and put into context with existing published works. Our analysis showed that indoor IS levels were below auditory threshold levels while LFN levels at distances >500 m were similar to background LFN levels. A clear contribution to LFN due to wind turbine operation (i.e., measured with turbines on in comparison to with turbines off) was noted at a distance of 480 m. However, this corresponded to an increase in overall audible sound measures as reported in dB(A), supporting the hypothesis that controlling audible sound produced by normally operating wind turbines will also control for LFN. Overall, the available data from this and other studies suggest that health-based audible noise wind turbine siting guidelines provide an effective means to evaluate, monitor, and protect potential receptors from audible noise as well as IS and LFN. PMID:25759808

Health-based audible noise guidelines account for infrasound and low-frequency noise produced by wind turbines.

PubMed

Berger, Robert G; Ashtiani, Payam; Ollson, Christopher A; Whitfield Aslund, Melissa; McCallum, Lindsay C; Leventhall, Geoff; Knopper, Loren D

2015-01-01

Setbacks for wind turbines have been established in many jurisdictions to address potential health concerns associated with audible noise. However, in recent years, it has been suggested that infrasound (IS) and low-frequency noise (LFN) could be responsible for the onset of adverse health effects self-reported by some individuals living in proximity to wind turbines, even when audible noise limits are met. The purpose of this paper was to investigate whether current audible noise-based guidelines for wind turbines account for the protection of human health, given the levels of IS and LFN typically produced by wind turbines. New field measurements of indoor IS and outdoor LFN at locations between 400 and 900 m from the nearest turbine, which were previously underrepresented in the scientific literature, are reported and put into context with existing published works. Our analysis showed that indoor IS levels were below auditory threshold levels while LFN levels at distances >500 m were similar to background LFN levels. A clear contribution to LFN due to wind turbine operation (i.e., measured with turbines on in comparison to with turbines off) was noted at a distance of 480 m. However, this corresponded to an increase in overall audible sound measures as reported in dB(A), supporting the hypothesis that controlling audible sound produced by normally operating wind turbines will also control for LFN. Overall, the available data from this and other studies suggest that health-based audible noise wind turbine siting guidelines provide an effective means to evaluate, monitor, and protect potential receptors from audible noise as well as IS and LFN.

PIV study of the wake of a model wind turbine transitioning between operating set points

NASA Astrophysics Data System (ADS)

Houck, Dan; Cowen, Edwin (Todd)

2016-11-01

Wind turbines are ideally operated at their most efficient tip speed ratio for a given wind speed. There is increasing interest, however, in operating turbines at other set points to increase the overall power production of a wind farm. Specifically, Goit and Meyers (2015) used LES to examine a wind farm optimized by unsteady operation of its turbines. In this study, the wake of a model wind turbine is measured in a water channel using PIV. We measure the wake response to a change in operational set point of the model turbine, e.g., from low to high tip speed ratio or vice versa, to examine how it might influence a downwind turbine. A modified torque transducer after Kang et al. (2010) is used to calibrate in situ voltage measurements of the model turbine's generator operating across a resistance to the torque on the generator. Changes in operational set point are made by changing the resistance or the flow speed, which change the rotation rate measured by an encoder. Single camera PIV on vertical planes reveals statistics of the wake at various distances downstream as the turbine transitions from one set point to another. From these measurements, we infer how the unsteady operation of a turbine may affect the performance of a downwind turbine as its incoming flow. National Science Foundation and the Atkinson Center for a Sustainable Future.

Wind-driven roof turbines: a novel way to improve ventilation for TB infection control in health facilities.

PubMed

Cox, Helen; Escombe, Rod; McDermid, Cheryl; Mtshemla, Yolanda; Spelman, Tim; Azevedo, Virginia; London, Leslie

2012-01-01

Tuberculosis transmission in healthcare facilities contributes significantly to the TB epidemic, particularly in high HIV settings. Although improving ventilation may reduce transmission, there is a lack of evidence to support low-cost practical interventions. We assessed the efficacy of wind-driven roof turbines to achieve recommended ventilation rates, compared to current recommended practices for natural ventilation (opening windows), in primary care clinic rooms in Khayelitsha, South Africa. Room ventilation was assessed (CO₂ gas tracer technique) in 4 rooms where roof turbines and air-intake grates were installed, across three scenarios: turbine, grate and window closed, only window open, and only turbine and grate open, with concurrent wind speed measurement. 332 measurements were conducted over 24 months. For all 4 rooms combined, median air changes per hour (ACH) increased with wind speed quartiles across all scenarios. Higher median ACH were recorded with open roof turbines and grates, compared to open windows across all wind speed quartiles. Ventilation with open turbine and grate exceeded WHO-recommended levels (60 Litres/second/patient) for 95% or more of measurements in 3 of the 4 rooms; 47% in the remaining room, where wind speeds were lower and a smaller diameter turbine was installed. High room ventilation rates, meeting recommended thresholds, may be achieved using wind-driven roof turbines and grates, even at low wind speeds. Roof turbines and air-intake grates are not easily closed by staff, allowing continued ventilation through colder periods. This simple, low-cost technology represents an important addition to our tools for TB infection control.

Wind-Driven Roof Turbines: A Novel Way to Improve Ventilation for TB Infection Control in Health Facilities

PubMed Central

Cox, Helen; Escombe, Rod; McDermid, Cheryl; Mtshemla, Yolanda; Spelman, Tim; Azevedo, Virginia; London, Leslie

2012-01-01

Objective Tuberculosis transmission in healthcare facilities contributes significantly to the TB epidemic, particularly in high HIV settings. Although improving ventilation may reduce transmission, there is a lack of evidence to support low-cost practical interventions. We assessed the efficacy of wind-driven roof turbines to achieve recommended ventilation rates, compared to current recommended practices for natural ventilation (opening windows), in primary care clinic rooms in Khayelitsha, South Africa. Methods Room ventilation was assessed (CO2 gas tracer technique) in 4 rooms where roof turbines and air-intake grates were installed, across three scenarios: turbine, grate and window closed, only window open, and only turbine and grate open, with concurrent wind speed measurement. 332 measurements were conducted over 24 months. Findings For all 4 rooms combined, median air changes per hour (ACH) increased with wind speed quartiles across all scenarios. Higher median ACH were recorded with open roof turbines and grates, compared to open windows across all wind speed quartiles. Ventilation with open turbine and grate exceeded WHO-recommended levels (60 Litres/second/patient) for 95% or more of measurements in 3 of the 4 rooms; 47% in the remaining room, where wind speeds were lower and a smaller diameter turbine was installed. Conclusion High room ventilation rates, meeting recommended thresholds, may be achieved using wind-driven roof turbines and grates, even at low wind speeds. Roof turbines and air-intake grates are not easily closed by staff, allowing continued ventilation through colder periods. This simple, low-cost technology represents an important addition to our tools for TB infection control. PMID:22253742

Fabrication and assembly of the ERDA/NASA 100 kilowatt experimental wind turbine

NASA Technical Reports Server (NTRS)

Puthoff, R. L.

1976-01-01

As part of the Energy Research and Development Administration (ERDA) wind-energy program, NASA Lewis Research Center has designed and built an experimental 100-kW wind turbine. The two-bladed turbines drives a synchronous alternator that generates its maximum output of 100 kW of electrical power in a 29-km/hr (18-mph) wind. The design and assembly of the wind turbine were performed at Lewis from components that were procured from industry. The machine was installed atop the tower on September 3, 1975.

Study of Vertical Axis Wind Turbine for Energy Harvester in A Fishing Boat

NASA Astrophysics Data System (ADS)

Budi, E. M.; Banjarnahor, D. A.; Hanifan, M.

2017-07-01

The wind speed in the southern beach of West Java Indonesia is quite promising for wind energy harvesting. A field survey reported that the wind speed reached 10 m/s, while the average recorded in a year is about 4.7 m/s. In this study, two vertical axis wind turbines (VAWT) were compared to be used in that area through calculation as well as experiments. The experiments measured that the turbines can produce about 7.82W and 2.33W of electricity respectively. These experiments are compared with theoretical calculation to obtain the performance of both turbines used. The coefficient of performance (cp) experimentally is 0.09 for Turbine 1 (hybrid Savonius-Darrieus rotor) and 0.14 for Turbine 2 (Savonius rotor). While, rotor’s mechanical performance Cpr, obtained theoritically through calculation, is 0.36 for Turbine 1 and 0.12 for Turbine 2. These results are analysed from mechanical and electrical view.

Do terrestrial animals avoid areas close to turbines in functioning wind farms in agricultural landscapes?

PubMed

Łopucki, Rafał; Klich, Daniel; Gielarek, Sylwia

2017-07-01

Most studies on the effects of wind energy on animals have focused on avian and bat activity, habitat use, and mortality, whereas very few have been published on terrestrial, non-volant wildlife. In this paper, we studied the utilization of functioning wind farm areas by four terrestrial animals common to agricultural landscapes: European roe deer, European hare, red fox, and the common pheasant. Firstly, we expected that the studied animals do not avoid areas close to turbines and utilize the whole area of functioning wind farms with a frequency similar to the control areas. Secondly, we expected that there is no relation between the turbine proximity and the number of tracks of these animals. The study was conducted over two winter seasons using the snow-tracking method along 100 m linear transects. In total, 583 transects were recorded. Wind farm operations may affect terrestrial animals both in wind farm interiors and in a 700-m buffer zone around the edge of turbines. The reactions of animals were species specific. Herbivorous mammals (roe deer and European hare) avoided wind farm interiors and proximity to turbines. The common pheasant showed a positive reaction to wind turbine proximity. The red fox had the most neutral response to wind turbines. Although this species visited wind farm interiors less often than the control area, there was no relation between fox track density and turbine proximity. Greater weight should be given to the effects of wind farms on non-flying wildlife than at present. Investors and regulatory authorities should always consider the likely impacts of wind farms during environmental impact assessments and try to reduce these negative effects.

The capacity credit of grid-connected photovoltaic systems

NASA Astrophysics Data System (ADS)

Alsema, E. A.; van Wijk, A. J. M.; Turkenburg, W. C.

The capacity credit due photovoltaic (PV) power plants if integrated into the Netherlands grid was investigated, together with an estimate of the total allowable penetration. An hourly simulation was performed based on meteorological data from five stations and considering tilted surfaces, the current grid load pattern, and the load pattern after PV-power augmentation. The reliability of the grid was assessed in terms of a loss of load probability analysis, assuming power drops were limited to 1 GW. A projected tolerance for 2.5 GW of PV power was calculated. Peak demands were determined to be highest in winter, contrary to highest insolation levels; however, daily insolation levels coincided with daily peak demands. Combining the PV input with an equal amount of wind turbine power production was found to augment the capacity credit for both at aggregate outputs of 2-4 GW.

78 FR 20690 - Draft Environmental Impact Statement, Draft Habitat Conservation Plan, Draft Programmatic...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-05

.... Background The Fowler Ridge application is unusual in that 355 wind turbines are already in place and have... turbines under Phase IV and operate a maximum of 449 wind turbines and associated facilities (described below) for a period of 22 years in Benton County, Indiana. The project will consist of wind turbines...

76 FR 54481 - Wind Turbine Guidelines Advisory Committee; Announcement of Public Meeting and Webcast

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-01

..., the U.S. Fish and Wildlife Service (Service), will host a Wind Turbine Guidelines Advisory Committee...] RIN 1018-AX45 Wind Turbine Guidelines Advisory Committee; Announcement of Public Meeting and Webcast..., representing the varied interests associated with wind energy development and its potential impacts to wildlife...

Wind Turbine Infra and Low-Frequency Sound: Warning Signs that Were Not Heard

ERIC Educational Resources Information Center

James, Richard R.

2012-01-01

Industrial wind turbines are frequently thought of as benign. However, the literature is reporting adverse health effects associated with the implementation of industrial-scale wind developments. This article explores the historical evidence about what was known regarding infra and low-frequency sound from wind turbines and other noise sources…

Systems Engineering 2010 Workshop | Wind | NREL

Science.gov Websites

turbine aeroelastic model, inflow turbulence model, wind plan layout and interactions, resource model, O on the approach to wind turbine design, choice, and deployment 2:40 Break Computer Science perspective) International Laboratories 3:20 Bernard Bulder, ECN Integral Wind Turbine Design with Focus-6 3

76 FR 52966 - Kawailoa Wind Energy Generation Facility, Oahu, HI; Draft Habitat Conservation Plan and Draft...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-24

.... The proposed facility will consist of 30 wind turbine generators (WTGs), a maintenance building, an... sandvicensis), and Hawaiian hoary bat, which have collided with the wind turbine structures at this existing 30... (collisions with wind turbine generators). In addition to the anticipated take by the project, predator...

OUT Success Stories: Advanced Airfoils for Wind Turbines

DOE R&D Accomplishments Database

Jones, J.; Green, B.

2000-08-01

New airfoils have substantially increased the aerodynamic efficiency of wind turbines. It is clear that these new airfoils substantially increased energy output from wind turbines. Virtually all new blades built in this country today use these advanced airfoil designs.

Evaluation of surface energy and carbon fluxes within a large wind farm during the CWEX-10/11 Crop Wind-energy EXperiments

NASA Astrophysics Data System (ADS)

Rajewski, D. A.; Takle, E. S.; Prueger, J. H.; Oncley, S.; Horst, T. W.; Pfeiffer, R.; Hatfield, J.; Spoth, K. K.; Doorenbos, R.

2012-12-01

The Crop Wind-energy EXperiment conducted in summer 2010 (very moist conditions) and summer 2011 (abnormally dry) included measurements of wind speed, temperature, relative humidity, turbulence kinetic energy, H2O, and CO2 at stations north and south of a line of turbines at the southwest edge of a large-scale 200-turbine wind farm (prevailing wind from the south). In contrast to previous studies that have reported turbine influences on surface wind speed and temperature, this report focuses on scalar fluxes of heat, H2O, and CO2. From previous measurements in agricultural fields we recognize the importance of non-turbine factors in analysis of the flux differences: variability of soil characteristics, moisture content, crop cultivar, management practices, planting dates, etc., which can create differences in what looks like a uniform field of maize (corn). We conceptualize the influences of turbines at canopy height at a given location in the field to arise from (1) wakes of reduced wind speed and turbulence conditions different from ambient that intersect the surface, (2) wakes that are passing overhead and interrupt the ambient turbulence that scales with height, or (3) changes in static pressure upwind and downwind of lines of turbines that create small-scale pressure gradients, localized flows, and changes to the vertical exchange of scalar variables. The turbine SCADA wind speed and wind direction provided by the wind farm operator facilitated our comparison of surface fluxes upwind and downwind as wakes moved laterally throughout the day and night. We report multiple levels of evidence that wind turbines increase vertical exchange of carbon dioxide and water vapor over the canopy. Latent heat and carbon fluxes are responsive to slight changes in the turbine wake position, and the flux differences are maximized when the periphery of the wake edge is above the station. The flux stations north of the turbine line report a larger net ecosystem exchange accumulation over both the 2010 and 2011 measurement periods than for the reference towers south of the turbine line. Future experiments however, must address if and to what extent this enhanced CO2 flux is assimilated to the crop and whether or not the bio-physiological response to this effect among many other turbine-related factors (e.g. higher nighttime temperature and higher daytime transpiration) modifies overall crop yield.

2012 Market Report on U.S. Wind Technologies in Distributed Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orrell, Alice C.; Flowers, L. T.; Gagne, M. N.

2013-08-06

At the end of 2012, U.S. wind turbines in distributed applications reached a 10-year cumulative installed capacity of more than 812 MW from more than 69,000 units across all 50 states. In 2012 alone, nearly 3,800 wind turbines totaling 175 MW of distributed wind capacity were documented in 40 states and in the U.S. Virgin Islands, with 138 MW using utility-scale turbines (i.e., greater than 1 MW in size), 19 MW using mid-size turbines (i.e., 101 kW to 1 MW in size), and 18.4 MW using small turbines (i.e., up to 100 kW in size). Distributed wind is defined inmore » terms of technology application based on a wind project’s location relative to end-use and power-distribution infrastructure, rather than on technology size or project size. Distributed wind systems are either connected on the customer side of the meter (to meet the onsite load) or directly to distribution or micro grids (to support grid operations or offset large loads nearby). Estimated capacity-weighted average costs for 2012 U.S. distributed wind installations was $2,540/kW for utility-scale wind turbines, $2,810/kW for mid-sized wind turbines, and $6,960/kW for newly manufactured (domestic and imported) small wind turbines. An emerging trend observed in 2012 was an increased use of refurbished turbines. The estimated capacity-weighted average cost of refurbished small wind turbines installed in 2012 was $4,080/kW. As a result of multiple projects using utility-scale turbines, Iowa deployed the most new overall distributed wind capacity, 37 MW, in 2012. Nevada deployed the most small wind capacity in 2012, with nearly 8 MW of small wind turbines installed in distributed applications. In the case of mid-size turbines, Ohio led all states in 2012 with 4.9 MW installed in distributed applications. State and federal policies and incentives continued to play a substantial role in the development of distributed wind projects. In 2012, U.S. Treasury Section 1603 payments and grants and loans from the U.S. Department of Agriculture’s Rural Energy for America Program were the main sources of federal funding for distributed wind projects. State and local funding varied across the country, from rebates to loans, tax credits, and other incentives. Reducing utility bills and hedging against potentially rising electricity rates remain drivers of distributed wind installations. In 2012, other drivers included taking advantage of the expiring U.S. Treasury Section 1603 program and a prosperous year for farmers. While 2012 saw a large addition of distributed wind capacity, considerable barriers and challenges remain, such as a weak domestic economy, inconsistent state incentives, and very competitive solar photovoltaic and natural gas prices. The industry remains committed to improving the distributed wind marketplace by advancing the third-party certification process and introducing alternative financing models, such as third-party power purchase agreements and lease-to-own agreements more typical in the solar photovoltaic market. Continued growth is expected in 2013.« less

Computational Acoustic Beamforming for Noise Source Identification for Small Wind Turbines.

PubMed

Ma, Ping; Lien, Fue-Sang; Yee, Eugene

2017-01-01

This paper develops a computational acoustic beamforming (CAB) methodology for identification of sources of small wind turbine noise. This methodology is validated using the case of the NACA 0012 airfoil trailing edge noise. For this validation case, the predicted acoustic maps were in excellent conformance with the results of the measurements obtained from the acoustic beamforming experiment. Following this validation study, the CAB methodology was applied to the identification of noise sources generated by a commercial small wind turbine. The simulated acoustic maps revealed that the blade tower interaction and the wind turbine nacelle were the two primary mechanisms for sound generation for this small wind turbine at frequencies between 100 and 630 Hz.

Motion performance and mooring system of a floating offshore wind turbine

NASA Astrophysics Data System (ADS)

Zhao, Jing; Zhang, Liang; Wu, Haitao

2012-09-01

The development of offshore wind farms was originally carried out in shallow water areas with fixed (seabed mounted) structures. However, countries with limited shallow water areas require innovative floating platforms to deploy wind turbines offshore in order to harness wind energy to generate electricity in deep seas. The performances of motion and mooring system dynamics are vital to designing a cost effective and durable floating platform. This paper describes a numerical model to simulate dynamic behavior of a new semi-submersible type floating offshore wind turbine (FOWT) system. The wind turbine was modeled as a wind block with a certain thrust coefficient, and the hydrodynamics and mooring system dynamics of the platform were calculated by SESAM software. The effect of change in environmental conditions on the dynamic response of the system under wave and wind loading was examined. The results indicate that the semi-submersible concept has excellent performance and SESAM could be an effective tool for floating wind turbine design and analysis.

Spatial mapping and attribution of Wyoming wind turbines, 2012

USGS Publications Warehouse

O'Donnell, Michael S.; Fancher, Tammy S.

2014-01-01

These data represent locations of wind turbines found within Wyoming as of August 2012. We assigned each wind turbine to a wind farm and, in these data, provide information about each turbine’s potential megawatt output, rotor diameter, hub height, rotor height, the status of the land ownership where the turbine exists, the county each turbine is located in, wind farm power capacity, the number of units currently associated with each wind farm, the wind turbine manufacturer and model, the wind farm developer, the owner of the wind farm, the current purchaser of power from the wind farm, the year the wind farm went online, and the status of its operation. Some of the attributes are estimates based on the information we found via the American Wind Energy Association and other on-line reports. The locations are derived from National Agriculture Imagery Program (2009 and 2012) true color aerial photographs and have a positional accuracy of approximately +/-5 meters. These data will provide a planning tool for wildlife- and habitat-related projects underway at the U.S. Geological Survey’s Fort Collins Science Center and other government and non-government organizations. Specifically, we will use these data to support quantifying disturbances of the landscape as related to wind energy as well as to quantify indirect disturbances to flora and fauna. This data set represents an update to a previous version by O’Donnell and Fancher (2010).

Simplified formulae for the estimation of offshore wind turbines clutter on marine radars.

PubMed

Grande, Olatz; Cañizo, Josune; Angulo, Itziar; Jenn, David; Danoon, Laith R; Guerra, David; de la Vega, David

2014-01-01

The potential impact that offshore wind farms may cause on nearby marine radars should be considered before the wind farm is installed. Strong radar echoes from the turbines may degrade radars' detection capability in the area around the wind farm. Although conventional computational methods provide accurate results of scattering by wind turbines, they are not directly implementable in software tools that can be used to conduct the impact studies. This paper proposes a simple model to assess the clutter that wind turbines may generate on marine radars. This method can be easily implemented in the system modeling software tools for the impact analysis of a wind farm in a real scenario.

Simplified Formulae for the Estimation of Offshore Wind Turbines Clutter on Marine Radars

PubMed Central

Grande, Olatz; Cañizo, Josune; Jenn, David; Danoon, Laith R.; Guerra, David

2014-01-01

The potential impact that offshore wind farms may cause on nearby marine radars should be considered before the wind farm is installed. Strong radar echoes from the turbines may degrade radars' detection capability in the area around the wind farm. Although conventional computational methods provide accurate results of scattering by wind turbines, they are not directly implementable in software tools that can be used to conduct the impact studies. This paper proposes a simple model to assess the clutter that wind turbines may generate on marine radars. This method can be easily implemented in the system modeling software tools for the impact analysis of a wind farm in a real scenario. PMID:24782682

IEA Wind Task 37: Systems Modeling Framework and Ontology for Wind Turbines and Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dykes, Katherine L; Zahle, Frederik; Merz, Karl

This presentation will provide an overview of progress to date in the development of a system modeling framework and ontology for wind turbines and plants as part of the larger IEA Wind Task 37 on wind energy systems engineering. The goals of the effort are to create a set of guidelines for a common conceptual architecture for wind turbines and plants so that practitioners can more easily share descriptions of wind turbines and plants across multiple parties and reduce the effort for translating descriptions between models; integrate different models together and collaborate on model development; and translate models among differentmore » levels of fidelity in the system.« less

Construction of a Mod-0A Wind Turbine in Clayton, New Mexico

NASA Image and Video Library

1977-11-21

TA Mod-0A 200-kilowatt wind turbine designed by National Aeronautics and Space Administration (NASA) Lewis Research Center and constructed in Clayton, New Mexico. The wind turbine program was a joint effort by NASA and the Energy Research and Development Administration (ERDA) during the 1970s to develop less expensive forms of energy. NASA Lewis was assigned the responsibility of developing large horizontal-axis wind turbines. The program included a series of increasingly powerful wind turbines, designated: Mod-0A, Mod-1, WTS-4, and Mod-5. The program’s first device was a Mod-0 100-kilowatt wind turbine test bed built at NASA’s Plum Brook Station. This Mod-0A 200-kilowatt turbine built in Clayton in 1977 was the program’s second device. It included a 125-foot long blade atop a 100-foot tall tower. The Mod-0A was designed to determine the turbine’s operating problems, integrate the system with the local utilities, and assess the attitude of the local community. There were additional Mod-0A turbines built in Culebra, Puerto Rico; Block Island, Rhode Island; and Oahu, Hawaii. The Mod-0A turbines were initially unreliable and suffered issues with the durability of the rotor blade. Lewis engineers addressed the problems, and the wind turbines proved to be reliable and efficient devices that operated for a number of years. The information gained from these early models was vital to the design and improvement of the later generations.

Wind flow through shrouded wind turbines

DTIC Science & Technology

2017-03-01

were so patient with me during this process, sometimes spending hours in the wind tunnel room with me while I performed what seemed like endless runs ...disorderly wind velocities that result from the rotating turbine blades . In 2011, a study conducted by the White House Office of Science and...targets, and scattering target returns” [4]. Furthermore, the shadowing effects from spinning wind turbine blades can adversely impact air-traffic

Wind Power Innovation Enables Shift to Utility-Scale - Continuum Magazine

Science.gov Websites

the 1930s, a farmer in South Dakota built a small wind turbine on his farm, generating enough enough electricity to power thousands of homes. Aerial photo of large wind turbine with mountains in the background. Aerial view of the Siemens utility-scale wind turbine at the National Wind Technology Center

Locations and attributes of wind turbines in Colorado, 2011

USGS Publications Warehouse

Carr, Natasha B.; Diffendorfer, James E.; Fancher, Tammy; Hawkins, Sarah J.; Latysh, Natalie; Leib, Kenneth J.; Matherne, Anne Marie

2013-01-01

This dataset represents an update to U.S. Geological Survey Data Series 597. Locations and attributes of wind turbines in Colorado, 2009 (available at http://pubs.usgs.gov/ds/597/). This updated Colorado wind turbine Data Series provides geospatial data for all 1,204 wind turbines established within the State of Colorado as of September 2011, an increase of 297 wind turbines from 2009. Attributes specific to each turbine include: turbine location, manufacturer and model, rotor diameter, hub height, rotor height, potential megawatt output, land ownership, county, and development status of the wind turbine. Wind energy facility data for each turbine include: facility name, facility power capacity, number of turbines associated with each facility to date, facility developer, facility ownership, and year the facility went online. The locations of turbines are derived from 1-meter true-color aerial photographs produced by the National Agriculture Imagery Program (NAIP); the photographs have a positional accuracy of about ±5 meters. Locations of turbines constructed during or prior to August 2009 are based on August 2009 NAIP imagery and turbine locations constructed after August 2009 were based on September 2011 NAIP imagery. The location of turbines under construction during September 2011 likely will be less accurate than the location of existing turbines. This data series contributes to an Online Interactive Energy Atlas developed by the U.S. Geological Survey (http://my.usgs.gov/eerma/). The Energy Atlas synthesizes data on existing and potential energy development in Colorado and New Mexico and includes additional natural resource data layers. This information may be used by decisionmakers to evaluate and compare the potential benefits and tradeoffs associated with different energy development strategies or scenarios. Interactive maps, downloadable data layers, comprehensive metadata, and decision-support tools also are included in the Energy Atlas. The format of the Energy Atlas is designed to facilitate the integration of information about energy with key terrestrial and aquatic resources for evaluating resource values and minimizing risks from energy development.

Locations and attributes of wind turbines in New Mexico, 2011

USGS Publications Warehouse

Carr, Natasha B.; Diffendorfer, James B.; Fancher, Tammy; Hawkins, Sarah J.; Latysh, Natalie; Leib, Kenneth J.; Matherne, Anne Marie

2013-01-01

This dataset represents an update to U.S. Geological Survey Data Series 596. Locations and attributes of wind turbines in New Mexico, 2009 (available at http://pubs.usgs.gov/ds/596/).This updated New Mexico wind turbine Data Series provides geospatial data for all 562 wind turbines established within the State of New Mexico as of June 2011, an increase of 155 wind turbines from 2009. Attributes specific to each turbine include: turbine location, manufacturer and model, rotor diameter, hub height, rotor height, potential megawatt output, land ownership, county, and development status of wind turbine. Wind energy facility data for each turbine include: facility name, facility power capacity, number of turbines associated with each facility to date, facility developer, facility ownership, and year the facility went online. The locations of turbines are derived from 1-meter true-color aerial photographs produced by the National Agriculture Imagery Program (NAIP); the photographs have a positional accuracy of about ±5 meters. The locations of turbines constructed during or prior to August 2009 are based on August 2009 NAIP imagery and turbine locations constructed after August 2009 were based June 2011 NAIP imagery. The location of turbines under construction during June 2011 likely will be less accurate than the location of existing turbines. This data series contributes to an Online Interactive Energy Atlas developed by the U.S. Geological Survey (http://my.usgs.gov/eerma/). The Energy Atlas synthesizes data on existing and potential energy development in Colorado and New Mexico and includes additional natural resource data layers. This information may be used by decisionmakers to evaluate and compare the potential benefits and tradeoffs associated with different energy development strategies or scenarios. Interactive maps, downloadable data layers, comprehensive metadata, and decision-support tools also are included in the Energy Atlas. The format of the Energy Atlas is designed to facilitate the integration of information about energy with key terrestrial and aquatic resources for evaluating resource values and minimizing risks from energy development.

High Work, High-Efficiency Turbines for Uninhabited Aerial Vehicles (UAVs)

DTIC Science & Technology

2013-09-01

controlling highly loaded LP turbine blades have been demonstrated in a low speed linear cascade at the AFRL Low Speed Wind Tunnel (LSWT) facility that...34, pp. 1570-1577. [34] Selig M. S. and Mcgranahan, B. D., “ Wind Tunnel Aerodynamic Tests of Six Airfoils for Use on Small Wind Turbines .” National...aerodynamic flows is of interest in many design domains such as air vehicles, turbomachinery, and wind turbines . Micro-air-vehicles (MAV) which have small

Incorporation of Outcome-Based Contract Requirements in a Real Options Approach for Maintenance Planning

DTIC Science & Technology

2016-04-30

focus on novel onshore/offshore and small/large scale wind turbine designs for expanding their operational range and increasing their efficiency at...of maintenance options created by the implementation of PHM in wind turbines . When an RUL is predicted for a subsystem, there are multiple choices...The section titled Example— Wind Turbine With an Outcome-Based Contract presents a case study for a PHM enabled wind turbine with and without an

NWTC Researchers Field-Test Advanced Control Turbine Systems to Increase Performance, Decrease Structural Loading of Wind Turbines and Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Researchers at the National Renewable Energy Laboratory's (NREL's) National Wind Technology Center (NWTC) are studying component controls, including new advanced actuators and sensors, for both conventional turbines as well as wind plants. This research will help develop innovative control strategies that reduce aerodynamic structural loads and improve performance. Structural loads can cause damage that increase maintenance costs and shorten the life of a turbine or wind plant.

Utility operational experience on the NASA/DOE Mod-OA 200 kW Wind Turbine

NASA Technical Reports Server (NTRS)

Glasgow, J. C.; Robbins, W. H.

1979-01-01

The Mod-OA 200 kW Wind Turbine was designed and fabricated by the Lewis Research Center of the NASA under the direction of the U.S. Department of Energy. The project is a part of the Federal Wind Energy Program and is designed to obtain early wind turbine operation and performance data while gaining initial experience in the operation of large, horizontal axis wind turbines in typical utility environments. On March 6, 1978, the Mod-OA wind turbine was turned over to the Town of Clayton Light and Water Plant, Clayton, NM, for utility operation and on December 31, 1978 the machine had completed ten months of utility operation. This paper describes the machine and documents the recent operational experience at Clayton, NM.

Synergistic Effects of Turbine Wakes and Atmospheric Stability on Power Production at an Onshore Wind Farm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wharton, S; Lundquist, J K; Marjanovic, N

This report examines the complex interactions between atmospheric stability and turbine-induced wakes on downwind turbine wind speed and power production at a West Coast North American multi-MW wind farm. Wakes are generated when the upwind flow field is distorted by the mechanical movement of the wind turbine blades. This has two consequences for downwind turbines: (1) the downwind turbine encounters wind flows with reduced velocity and (2) the downwind turbine encounters increased turbulence across multiple length scales via mechanical turbulence production by the upwind turbine. This increase in turbulence on top of ambient levels may increase aerodynamic fatigue loads onmore » the blades and reduce the lifetime of turbine component parts. Furthermore, ambient atmospheric conditions, including atmospheric stability, i.e., thermal stratification in the lower boundary layer, play an important role in wake dissipation. Higher levels of ambient turbulence (i.e., a convective or unstable boundary layer) lead to higher turbulent mixing in the wake and a faster recovery in the velocity flow field downwind of a turbine. Lower levels of ambient turbulence, as in a stable boundary layer, will lead to more persistent wakes. The wake of a wind turbine can be divided into two regions: the near wake and far wake, as illustrated in Figure 1. The near wake is formed when the turbine structure alters the shape of the flow field and usually persists one rotor diameter (D) downstream. The difference between the air inside and outside of the near wake results in a shear layer. This shear layer thickens as it moves downstream and forms turbulent eddies of multiple length scales. As the wake travels downstream, it expands depending on the level of ambient turbulence and meanders (i.e., travels in non-uniform path). Schepers estimates that the wake is fully expanded at a distance of 2.25 D and the far wake region begins at 2-5 D downstream. The actual distance traveled before the wake recovers to its inflow velocity is dependent on the amount ambient turbulence, the amount of wind shear, and topographical and structural effects. The maximum velocity deficit is estimated to occur at 1-2 D but can be longer under low levels of ambient turbulence. Our understanding of turbine wakes comes from wind tunnel experiments, field experiments, numerical simulations, and from studies utilizing both experimental and modeling methods. It is well documented that downwind turbines in multi-Megawatt wind farms often produce less power than upwind turbine rows. These wake-induced power losses have been estimated from 5% to up to 40% depending on the turbine operating settings (e.g., thrust coefficient), number of turbine rows, turbine size (e.g., rotor diameter and hub-height), wind farm terrain, and atmospheric flow conditions (e.g., ambient wind speed, turbulence, and atmospheric stability). Early work by Elliott and Cadogan suggested that power data for different turbulent conditions be segregated to distinguish the effects of turbulence on wind farm power production. This may be especially important for downwind turbines within wind farms, as chaotic and turbulent wake flows increase stress on downstream turbines. Impacts of stability on turbine wakes and power production have been examined for a flat terrain, moderate size (43 turbines) wind farm in Minnesota and for an offshore, 80 turbine wind farm off the coast of Denmark. Conzemius found it difficult to distinguish wakes (i.e., downwind velocity deficits) when the atmosphere was convective as large amounts of scatter were present in the turbine nacelle wind speed data. This suggested that high levels of turbulence broke-up the wake via large buoyancy effects, which are generally on the order of 1 km in size. On the other hand, they found pronounced wake effects when the atmosphere was very stable and turbulence was either suppressed or the length scale was reduced as turbulence in this case was mechanically produced (i.e., friction forces). This led to larger reductions at downwind turbines and maximum velocity (power) deficits reached up to 50% (70%) during strongly stable conditions. At an offshore Danish wind farm, Hansen et al. found a strong negative correlation between power deficit and ambient turbulence intensity (i.e., atmospheric stability). Under convective conditions, when turbulence levels were relatively high, smallest power deficits were observed. Power deficits approaching 35 to 40% were found inside the wind farm during stable conditions.« less

Comparison of Standard Wind Turbine Models with Vendor Models for Power System Stability Analysis: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Honrubia-Escribano, A.; Gomez Lazaro, E.; Jimenez-Buendia, F.

The International Electrotechnical Commission Standard 61400-27-1 was published in February 2015. This standard deals with the development of generic terms and parameters to specify the electrical characteristics of wind turbines. Generic models of very complex technological systems, such as wind turbines, are thus defined based on the four common configurations available in the market. Due to its recent publication, the comparison of the response of generic models with specific vendor models plays a key role in ensuring the widespread use of this standard. This paper compares the response of a specific Gamesa dynamic wind turbine model to the corresponding genericmore » IEC Type III wind turbine model response when the wind turbine is subjected to a three-phase voltage dip. This Type III model represents the doubly-fed induction generator wind turbine, which is not only one of the most commonly sold and installed technologies in the current market but also a complex variable-speed operation implementation. In fact, active and reactive power transients are observed due to the voltage reduction. Special attention is given to the reactive power injection provided by the wind turbine models because it is a requirement of current grid codes. Further, the boundaries of the generic models associated with transient events that cannot be represented exactly are included in the paper.« less

Wind turbine impact on operational weather radar I/Q data: characterisation and filtering

NASA Astrophysics Data System (ADS)

Norin, Lars

2017-05-01

For the past 2 decades wind turbines have been growing in number all over the world as a response to the increasing demand for renewable energy. However, the rapid expansion of wind turbines presents a problem for many radar systems, including weather radars. Wind turbines in the line of sight of a weather radar can have a negative impact on the radar's measurements. As weather radars are important instruments for meteorological offices, finding a way for wind turbines and weather radars to co-exist would be of great societal value.Doppler weather radars base their measurements on in-phase and quadrature phase (I/Q) data. In this work a month's worth of recordings of high-resolution I/Q data from an operational Swedish C-band weather radar are presented. The impact of point targets, such as masts and wind turbines, on the I/Q data is analysed and characterised. It is shown that the impact of point targets on single radar pulses, when normalised by amplitude, is manifested as a distinct and highly repeatable signature. The shape of this signature is found to be independent of the size, shape and yaw angle of the wind turbine. It is further demonstrated how the robustness of the point target signature can be used to identify and filter out the impact of wind turbines in the radar's signal processor.

Large-scale wind turbine structures

NASA Technical Reports Server (NTRS)

Spera, David A.

1988-01-01

The purpose of this presentation is to show how structural technology was applied in the design of modern wind turbines, which were recently brought to an advanced stage of development as sources of renewable power. Wind turbine structures present many difficult problems because they are relatively slender and flexible; subject to vibration and aeroelastic instabilities; acted upon by loads which are often nondeterministic; operated continuously with little maintenance in all weather; and dominated by life-cycle cost considerations. Progress in horizontal-axis wind turbines (HAWT) development was paced by progress in the understanding of structural loads, modeling of structural dynamic response, and designing of innovative structural response. During the past 15 years a series of large HAWTs was developed. This has culminated in the recent completion of the world's largest operating wind turbine, the 3.2 MW Mod-5B power plane installed on the island of Oahu, Hawaii. Some of the applications of structures technology to wind turbine will be illustrated by referring to the Mod-5B design. First, a video overview will be presented to provide familiarization with the Mod-5B project and the important components of the wind turbine system. Next, the structural requirements for large-scale wind turbines will be discussed, emphasizing the difficult fatigue-life requirements. Finally, the procedures used to design the structure will be presented, including the use of the fracture mechanics approach for determining allowable fatigue stresses.

Pressure retarded osmosis as a controlling system for traditional renewables

NASA Astrophysics Data System (ADS)

Carravetta, Armando; Fecarotta, Oreste; La Rocca, Michele; Martino, Riccardo

2015-04-01

Pressure retarded osmosis (PRO) is a viable but still not diffused form of renewable energy (see Maisonneuve et al., 2015 for a recent literature review). In PRO, water from a low salinity feed solution permeates through a membrane into a pressurized, high salinity draw solution, giving rise to a positive pressure drop; then energy is obtained by depressurizing the permeate through a hydro-turbine and brackish water is discharged. Many technological, environmental and economical aspects are obstacles in the diffusion of PRO, like the vulnerability of the membranes to fouling, the impact of the brackish water on the local marine environment, the high cost of membranes, etc. We are interested in the use of PRO as a combined form of energy with other renewable energy source like solar, wind or mini hydro in water supply networks (WSN). For the wide diffusion of renewables one of the major concerns of commercial power companies is to obtain very stable form of energy to comply with prescriptions of electricity grid operators and with the instant energy demand curve. Renewables are generally very variable form of energy, for the influence of climatic conditions on available power, and of the fluctuation in water demand in WSN. PRO is a very flexible technology where with appropriate turbines and control system power can be varied continuously to compensate for variation of other source of energy. Therefore, PRO is suitable to be used as a balancing system for commercial power system. We will present a simulation of the performance of a PRO used in combination with three different renewables. In the first two scenarios PRO compensate the difference between energy demand and energy production of a solar power plant and hydro power plant in a WSN. In the third scenario PRO is used to compensate daily variation of energy production in a wind power plant. Standard curves of energy production and energy demand for southern Italy are used. In order to control PRO production an appropriate hydro turbine system is necessary. Therefore, pumps as turbine (PAT) are used in alternative to a classical hydraulic turbine (Carravetta et al., 2013). PAT can be easily regulated by hydraulic system, of by an inverter, granting the necessary flexibility of energy production with a sensible reduction of machinery cost. Maisonneuve J, Pillay P, Laflamme C.B. Pressure-retarded osmotic power system model considering non-ideal effects. Renewable Energy. 2015; 75(3): 416-424. Carravetta A, Del Giudice G, Fecarotta O, Ramos HM. Pump as Turbine (PAT) Design in Water Distribution Network by System Effectiveness. Water. 2013; 5(3):1211-1225.

Impedance-based structural health monitoring of wind turbine blades

NASA Astrophysics Data System (ADS)

Pitchford, Corey; Grisso, Benjamin L.; Inman, Daniel J.

2007-04-01

Wind power is a fast-growing source of non-polluting, renewable energy with vast potential. However, current wind turbine technology must be improved before the potential of wind power can be fully realized. Wind turbine blades are one of the key components in improving this technology. Blade failure is very costly because it can damage other blades, the wind turbine itself, and possibly other wind turbines. A successful damage detection system incorporated into wind turbines could extend blade life and allow for less conservative designs. A damage detection method which has shown promise on a wide variety of structures is impedance-based structural health monitoring. The technique utilizes small piezoceramic (PZT) patches attached to a structure as self-sensing actuators to both excite the structure with high-frequency excitations, and monitor any changes in structural mechanical impedance. By monitoring the electrical impedance of the PZT, assessments can be made about the integrity of the mechanical structure. Recently, advances in hardware systems with onboard computing, including actuation and sensing, computational algorithms, and wireless telemetry, have improved the accessibility of the impedance method for in-field measurements. This paper investigates the feasibility of implementing such an onboard system inside of turbine blades as an in-field method of damage detection. Viability of onboard detection is accomplished by running a series of tests to verify the capability of the method on an actual wind turbine blade section from an experimental carbon/glass/balsa composite blade developed at Sandia National Laboratories.

Large eddy simulation study of the kinetic energy entrainment by energetic turbulent flow structures in large wind farms

NASA Astrophysics Data System (ADS)

VerHulst, Claire; Meneveau, Charles

2014-02-01

In this study, we address the question of how kinetic energy is entrained into large wind turbine arrays and, in particular, how large-scale flow structures contribute to such entrainment. Previous research has shown this entrainment to be an important limiting factor in the performance of very large arrays where the flow becomes fully developed and there is a balance between the forcing of the atmospheric boundary layer and the resistance of the wind turbines. Given the high Reynolds numbers and domain sizes on the order of kilometers, we rely on wall-modeled large eddy simulation (LES) to simulate turbulent flow within the wind farm. Three-dimensional proper orthogonal decomposition (POD) analysis is then used to identify the most energetic flow structures present in the LES data. We quantify the contribution of each POD mode to the kinetic energy entrainment and its dependence on the layout of the wind turbine array. The primary large-scale structures are found to be streamwise, counter-rotating vortices located above the height of the wind turbines. While the flow is periodic, the geometry is not invariant to all horizontal translations due to the presence of the wind turbines and thus POD modes need not be Fourier modes. Differences of the obtained modes with Fourier modes are documented. Some of the modes are responsible for a large fraction of the kinetic energy flux to the wind turbine region. Surprisingly, more flow structures (POD modes) are needed to capture at least 40% of the turbulent kinetic energy, for which the POD analysis is optimal, than are needed to capture at least 40% of the kinetic energy flux to the turbines. For comparison, we consider the cases of aligned and staggered wind turbine arrays in a neutral atmospheric boundary layer as well as a reference case without wind turbines. While the general characteristics of the flow structures are robust, the net kinetic energy entrainment to the turbines depends on the presence and relative arrangement of the wind turbines in the domain.

Effect of atmospheric turbulence on wind turbine wakes: An LES study

NASA Astrophysics Data System (ADS)

Wu, Y. T.; Porté-Agel, F.

2012-04-01

A comprehensive numerical study of atmospheric turbulence effect on wind-turbine wakes is presented. Large-eddy simulations of neutrally-stratified boundary layers developed over different flat surfaces (forest, farmland, grass, and snow) are performed to investigate the structure of turbine wakes in cases where the incident flows to the wind turbine have the same mean velocity at the hub height but different mean wind shears and turbulence intensity levels. The simulation results show that the different wind shears and turbulence intensity levels of the incoming flow lead to considerable influence on the spatial distribution of the mean velocity deficit, turbulence intensity, and turbulent shear stress in the wake region downstream of the turbine. In general, the recovery of the turbine-induced wake (velocity deficit) is faster and the turbulence intensity level is higher and has its maximum closer to the turbine for wakes of turbines over rougher terrain. In order to isolate the effect of turbulence intensity from that of wind shear, simulations have also been performed with synthetic inflow velocity fields that have the same mean wind shear but different turbulence intensity levels. We find that the effect of the inflow turbulence intensity on the wake recovery and turbulence levels is stronger than that of the mean shear.

Supplemental Environmental Impact Statement, Guam and Commonwealth of the Northern Mariana Islands Military Relocation (2012 Roadmap Adjustments)

DTIC Science & Technology

2015-07-01

Improvements & Traffic Signal Activation RF C-32 UoG UoG Wind Turbine University Drive 2013 Complete A 70-foot (21.3 m) wind turbine RC C-33 UoG... turbine Talofofo 2013 Contract approved 15 MW solar / wind turbine farm to help power 2,200 homes P S-5 GovGuam GWA Santa Rita Springs Booster...Rehabilitation of Asan Springs P B X X B B B C-31 GovGuam Route 26/25 Intersection Improvements RF B B X X B B B C-32 UoG Wind Turbine P

AeroDyn V15.04: Design tool for wind and MHK turbines

DOE Data Explorer

Murray, Robynne; Hayman, Greg; Jonkman, Jason

2017-04-28

AeroDyn is a time-domain wind and MHK turbine aerodynamics module that can be coupled into the FAST version 8 multi-physics engineering tool to enable aero-elastic simulation of horizontal-axis wind turbines. AeroDyn V15.04 has been updated to include a cavitation check for MHK turbines, and can be driven as a standalone code to compute wind turbine aerodynamic response uncoupled from FAST. Note that while AeroDyn has been updated to v15.04, FAST v8.16 has not yet been updated and still uses AeroDyn v15.03.

Aspects of structural health and condition monitoring of offshore wind turbines

PubMed Central

Antoniadou, I.; Dervilis, N.; Papatheou, E.; Maguire, A. E.; Worden, K.

2015-01-01

Wind power has expanded significantly over the past years, although reliability of wind turbine systems, especially of offshore wind turbines, has been many times unsatisfactory in the past. Wind turbine failures are equivalent to crucial financial losses. Therefore, creating and applying strategies that improve the reliability of their components is important for a successful implementation of such systems. Structural health monitoring (SHM) addresses these problems through the monitoring of parameters indicative of the state of the structure examined. Condition monitoring (CM), on the other hand, can be seen as a specialized area of the SHM community that aims at damage detection of, particularly, rotating machinery. The paper is divided into two parts: in the first part, advanced signal processing and machine learning methods are discussed for SHM and CM on wind turbine gearbox and blade damage detection examples. In the second part, an initial exploration of supervisor control and data acquisition systems data of an offshore wind farm is presented, and data-driven approaches are proposed for detecting abnormal behaviour of wind turbines. It is shown that the advanced signal processing methods discussed are effective and that it is important to adopt these SHM strategies in the wind energy sector. PMID:25583864

Aspects of structural health and condition monitoring of offshore wind turbines.

PubMed

Antoniadou, I; Dervilis, N; Papatheou, E; Maguire, A E; Worden, K

2015-02-28

Wind power has expanded significantly over the past years, although reliability of wind turbine systems, especially of offshore wind turbines, has been many times unsatisfactory in the past. Wind turbine failures are equivalent to crucial financial losses. Therefore, creating and applying strategies that improve the reliability of their components is important for a successful implementation of such systems. Structural health monitoring (SHM) addresses these problems through the monitoring of parameters indicative of the state of the structure examined. Condition monitoring (CM), on the other hand, can be seen as a specialized area of the SHM community that aims at damage detection of, particularly, rotating machinery. The paper is divided into two parts: in the first part, advanced signal processing and machine learning methods are discussed for SHM and CM on wind turbine gearbox and blade damage detection examples. In the second part, an initial exploration of supervisor control and data acquisition systems data of an offshore wind farm is presented, and data-driven approaches are proposed for detecting abnormal behaviour of wind turbines. It is shown that the advanced signal processing methods discussed are effective and that it is important to adopt these SHM strategies in the wind energy sector.

On the Use of Coupled Wind, Wave, and Current Fields in the Simulation of Loads on Bottom-Supported Offshore Wind Turbines during Hurricanes: March 2012 - September 2015

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Eungsoo; Manuel, Lance; Curcic, Milan

In the United States, potential offshore wind plant sites have been identified along the Atlantic seaboard and in the Gulf of Mexico. It is imperative that we define external conditions associated with hurricanes and severe winter storms and consider load cases for which wind turbines may need to be designed. We selected two hurricanes, Ike (2008) and Sandy (2012), and investigated the effect these tropical storms would have on bottom-supported offshore wind turbines that were hypothetically in or close to their path as they made landfall. For realistic turbine loads assessment, it is important that the coupled influences of themore » changing wind, wave, and current fields are simulated throughout the evolution of the hurricanes. We employed a coupled model--specifically, the University of Miami Coupled Model (UMCM)--that integrates atmospheric, wave, and ocean components to produce needed wind, wave, and current data. The wind data are used to generate appropriate vertical wind profiles and full wind velocity fields including turbulence; the current field over the water column is obtained by interpolated discrete output current data; and short-crested irregular second-order waves are simulated using output directional wave spectra from the coupled model. We studied two monopile-supported offshore wind turbines sited in 20 meters of water in the Gulf of Mexico to estimate loads during Hurricane Ike, and a jacket space-frame platform-supported offshore wind turbine sited in 50 meters of water in the mid-Atlantic region to estimate loads during Hurricane Sandy. In this report we discuss in detail how the simulated hurricane wind, wave, and current output data are used in turbine loads studies. In addition, important characteristics of the external conditions are studied, including the relative importance of swell versus wind seas, aerodynamic versus hydrodynamic forces, current velocity effects, yaw control options for the turbine, hydrodynamic drag versus inertia forces, and soil-structure interaction effects. A detailed framework is presented that explains how coupled inputs can be included in turbine loads studies during a hurricane. This framework can aid in future efforts aimed at developing offshore wind turbine design criteria and load cases related to hurricanes.« less

Cogging Torque Reduction in a Permanent Magnet Wind Turbine Generator: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muljadi, E.; Green, J.

2002-01-01

In this paper, we investigate three design options to minimize cogging torque: uniformity of air gap, pole width, and skewing. Although the design improvement is intended for small wind turbines, it is also applicable to larger wind turbines.

Lidar-based Research and Innovation at DTU Wind Energy - a Review

NASA Astrophysics Data System (ADS)

Mikkelsen, T.

2014-06-01

As wind turbines during the past decade have increased in size so have the challenges met by the atmospheric boundary-layer meteorologists and the wind energy society to measure and characterize the huge-volume wind fields surpassing and driving them. At the DTU Wind Energy test site "Østerild" for huge wind turbines, the hub-height of a recently installed 8 MW Vestas V164 turbine soars 143 meters up above the ground, and its rotor of amazing 164 meters in diameter make the turbine tips flicker 225 meters into the sky. Following the revolution in photonics-based telecommunication at the turn of the Millennium new fibre-based wind lidar technologies emerged and DTU Wind Energy, at that time embedded within Rise National Laboratory, began in collaboration with researchers from wind lidar companies to measure remote sensed wind profiles and turbulence structures within the atmospheric boundary layer with the emerging, at that time new, all-fibre-based 1.55 μ coherent detection wind lidars. Today, ten years later, DTU Wind Energy routinely deploys ground-based vertical profilers instead of met masts for high-precision measurements of mean wind profiles and turbulence profiles. At the departments test site "Høvsøre" DTU Wind Energy also routinely calibrate and accredit wind lidar manufactures wind lidars. Meanwhile however, new methodologies for power curve assessment based on ground-based and nacelle based lidars have also emerged. For improving the turbines power curve assessments and for advancing their control with feed-forward wind measurements experience has also been gained with wind lidars installed on turbine nacelles and integrated into the turbines rotating spinners. A new mobile research infrastructure WindScanner.dk has also emerged at DTU Wind Energy. Wind and turbulence fields are today scanned from sets of three simultaneously in space and time synchronized scanning lidars. One set consists of three fast scanning continuous-wave based wind lidars (short-range system), and another consisting of three synchronized pulsed wind lidar systems (long-range system). Today, wind lidar profilers and WindScanners are routinely deployed and operated during field tests and measurement campaigns. Lidars have been installed and operated from ground, on offshore platforms, and also as scanning lidars integrated in operating turbines. As a result, wind profiles and also detailed 3D scanning of wind and turbulence fields have been achieved: 1) of the free wind aloft, 2) over complex terrain, 3) at coastal ranges with land-sea interfaces, 4) offshore, 5) in turbine inflow induction zone, and 6) of the complex and turbulent flow fields in the wakes inside wind parks.

Fish schooling as a basis for vertical axis wind turbine farm design.

PubMed

Whittlesey, Robert W; Liska, Sebastian; Dabiri, John O

2010-09-01

Most wind farms consist of horizontal axis wind turbines (HAWTs) due to the high power coefficient (mechanical power output divided by the power of the free-stream air through the turbine cross-sectional area) of an isolated turbine. However when in close proximity to neighboring turbines, HAWTs suffer from a reduced power coefficient. In contrast, previous research on vertical axis wind turbines (VAWTs) suggests that closely spaced VAWTs may experience only small decreases (or even increases) in an individual turbine's power coefficient when placed in close proximity to neighbors, thus yielding much higher power outputs for a given area of land. A potential flow model of inter-VAWT interactions is developed to investigate the effect of changes in VAWT spatial arrangement on the array performance coefficient, which compares the expected average power coefficient of turbines in an array to a spatially isolated turbine. A geometric arrangement based on the configuration of shed vortices in the wake of schooling fish is shown to significantly increase the array performance coefficient based upon an array of 16 x 16 wind turbines. The results suggest increases in power output of over one order of magnitude for a given area of land as compared to HAWTs.

Large HAWT wake measurement and analysis

NASA Technical Reports Server (NTRS)

Miller, A. H.; Wegley, H. L.; Buck, J. W.

1995-01-01

From the theoretical fluid dynamics point of view, the wake region of a large horizontal-axis wind turbine has been defined and described, and numerical models of wake behavior have been developed. Wind tunnel studies of single turbine wakes and turbine array wakes have been used to verify the theory and further refine the numerical models. However, the effects of scaling, rotor solidity, and topography on wake behavior are questions that remain unanswered. In the wind tunnel studies, turbines were represented by anything from scaled models to tea strainers or wire mesh disks whose solidity was equivalent to that of a typical wind turbine. The scale factor compensation for the difference in Reynolds number between the scale model and an actual turbine is complex, and not typically accounted for. Though it is wise to study the simpler case of wakes in flat topography, which can be easily duplicated in the wind tunnel, current indications are that wind turbine farm development is actually occurring in somewhat more complex terrain. Empirical wake studies using large horizontal-axis wind turbines have not been thoroughly composited, and, therefore, the results have not been applied to the well-developed theory of wake structure. The measurement programs have made use of both in situ sensor systems, such as instrumented towers, and remote sensors, such as kites and tethered, balloonborne anemometers. We present a concise overview of the work that has been performed, including our own, which is based on the philosophy that the MOD-2 turbines are probably their own best detector of both the momentum deficit and the induced turbulence effect downwind. Only the momentum deficit aspects of the wake/machine interactions have been addressed. Both turbine power output deficits and wind energy deficits as measured by the onsite meteorological towers have been analyzed from a composite data set. The analysis has also evidenced certain topographic influences on the operation of spatially diverse wind turbines.

Large HAWT wake measurement and analysis

NASA Astrophysics Data System (ADS)

Miller, A. H.; Wegley, H. L.; Buck, J. W.

1995-05-01

From the theoretical fluid dynamics point of view, the wake region of a large horizontal-axis wind turbine has been defined and described, and numerical models of wake behavior have been developed. Wind tunnel studies of single turbine wakes and turbine array wakes have been used to verify the theory and further refine the numerical models. However, the effects of scaling, rotor solidity, and topography on wake behavior are questions that remain unanswered. In the wind tunnel studies, turbines were represented by anything from scaled models to tea strainers or wire mesh disks whose solidity was equivalent to that of a typical wind turbine. The scale factor compensation for the difference in Reynolds number between the scale model and an actual turbine is complex, and not typically accounted for. Though it is wise to study the simpler case of wakes in flat topography, which can be easily duplicated in the wind tunnel, current indications are that wind turbine farm development is actually occurring in somewhat more complex terrain. Empirical wake studies using large horizontal-axis wind turbines have not been thoroughly composited, and, therefore, the results have not been applied to the well-developed theory of wake structure. The measurement programs have made use of both in situ sensor systems, such as instrumented towers, and remote sensors, such as kites and tethered, balloonborne anemometers. We present a concise overview of the work that has been performed, including our own, which is based on the philosophy that the MOD-2 turbines are probably their own best detector of both the momentum deficit and the induced turbulence effect downwind. Only the momentum deficit aspects of the wake/machine interactions have been addressed. Both turbine power output deficits and wind energy deficits as measured by the onsite meteorological towers have been analyzed from a composite data set. The analysis has also evidenced certain topographic influences on the operation of spatially diverse wind turbines.

Effects of turbine technology and land use on wind power resource potential

NASA Astrophysics Data System (ADS)

Rinne, Erkka; Holttinen, Hannele; Kiviluoma, Juha; Rissanen, Simo

2018-06-01

Estimates of wind power potential are relevant for decision-making in energy policy and business. Such estimates are affected by several uncertain assumptions, most significantly related to wind turbine technology and land use. Here, we calculate the technical and economic onshore wind power potentials with the aim to evaluate the impact of such assumptions using the case-study area of Finland as an example. We show that the assumptions regarding turbine technology and land use policy are highly significant for the potential estimate. Modern turbines with lower specific ratings and greater hub heights improve the wind power potential considerably, even though it was assumed that the larger rotors decrease the installation density and increase the turbine investment costs. New technology also decreases the impact of strict land use policies. Uncertainty in estimating the cost of wind power technology limits the accuracy of assessing economic wind power potential.

CFD Analysis of a Finite Linear Array of Savonius Wind Turbines

NASA Astrophysics Data System (ADS)

Belkacem, Belabes; Paraschivoiu, Marius

2016-09-01

Vertical axis wind turbines such as Savonius rotors have been shown to be suitable for low wind speeds normally associated with wind resources in all corners of the world. However, the efficiency of the rotor is low. This paper presents results of Computational Fluid Dynamics (CFD) simulations for an array of Savonius rotors that show a significant increase in efficiency. It looks at identifying the effect on the energy yield of a number of turbines placed in a linear array. Results from this investigation suggest that an increase in the energy yield could be achieved which can reach almost two times than the conventional Savonius wind turbine in the case of an array of 11turbines with a distance of 1.4R in between them. The effect of different TSR values and different wind inlet speeds on the farm has been studied for both a synchronous and asynchronous wind farm.

40 CFR 63.6095 - When do I have to comply with this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... stationary combustion turbine or a diffusion flame oil-fired stationary combustion turbine as defined by this... combustion turbine which is a lean premix oil-fired stationary combustion turbine or a diffusion flame oil... stationary combustion turbine or diffusion flame gas-fired stationary combustion turbine as defined by this...

40 CFR 63.6095 - When do I have to comply with this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

... stationary combustion turbine or a diffusion flame oil-fired stationary combustion turbine as defined by this... combustion turbine which is a lean premix oil-fired stationary combustion turbine or a diffusion flame oil... stationary combustion turbine or diffusion flame gas-fired stationary combustion turbine as defined by this...

40 CFR 63.6095 - When do I have to comply with this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... stationary combustion turbine or a diffusion flame oil-fired stationary combustion turbine as defined by this... combustion turbine which is a lean premix oil-fired stationary combustion turbine or a diffusion flame oil... stationary combustion turbine or diffusion flame gas-fired stationary combustion turbine as defined by this...

40 CFR 63.6095 - When do I have to comply with this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

... stationary combustion turbine or a diffusion flame oil-fired stationary combustion turbine as defined by this... combustion turbine which is a lean premix oil-fired stationary combustion turbine or a diffusion flame oil... stationary combustion turbine or diffusion flame gas-fired stationary combustion turbine as defined by this...

40 CFR 63.6095 - When do I have to comply with this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... stationary combustion turbine or a diffusion flame oil-fired stationary combustion turbine as defined by this... combustion turbine which is a lean premix oil-fired stationary combustion turbine or a diffusion flame oil... stationary combustion turbine or diffusion flame gas-fired stationary combustion turbine as defined by this...

A comparison of measured wind park load histories with the WISPER and WISPERX load spectra

NASA Astrophysics Data System (ADS)

Kelley, N. D.

1995-01-01

The blade-loading histories from two adjacent Micon 65/13 wind turbines are compared with the variable-amplitude test-loading histories known as the WISPER and WISPERX spectra. These standardized loading sequences were developed from blade flapwise load histories taken from nine different horizontal-axis wind turbines operating under a wide range of conditions in Europe. The subject turbines covered a broad spectrum of rotor diameters, materials, and operating environments. The final loading sequences were developed as a joint effort of thirteen different European organizations. The goal was to develop a meaningful loading standard for horizontal-axis wind turbine blades that represents common interaction effects seen in service. In 1990, NREL made extensive load measurements on two adjacent Micon 65/13 wind turbines in simultaneous operation in the very turbulent environment of a large wind park. Further, before and during the collection of the loads data, comprehensive measurements of the statistics of the turbulent environment were obtained at both the turbines under test and at two other locations within the park. The trend to larger but lighter wind turbine structures has made an understanding of the expected lifetime loading history of paramount importance. Experience in the US has shown that the turbulence-induced loads associated with multi-row wind parks in general are much more severe than for turbines operating individually or within widely spaced environments. Multi-row wind parks are much more common in the US than in Europe. In this paper we report on our results in applying the methodology utilized to develop the WISPER and WISPERX standardized loading sequences using the available data from the Micon turbines. While the intended purpose of the WISPER sequences were not to represent a specific operating environment, we believe the exercise is useful, especially when a turbine design is likely to be installed in a multi-row wind park.

Aerodynamic optimization of wind turbine rotor using CFD/AD method

NASA Astrophysics Data System (ADS)

Cao, Jiufa; Zhu, Weijun; Wang, Tongguang; Ke, Shitang

2018-05-01

The current work describes a novel technique for wind turbine rotor optimization. The aerodynamic design and optimization of wind turbine rotor can be achieved with different methods, such as the semi-empirical engineering methods and more accurate computational fluid dynamic (CFD) method. The CFD method often provides more detailed aerodynamics features during the design process. However, high computational cost limits the application, especially for rotor optimization purpose. In this paper, a CFD-based actuator disc (AD) model is used to represent turbulent flow over a wind turbine rotor. The rotor is modeled as a permeable disc of equivalent area where the forces from the blades are distributed on the circular disc. The AD model is coupled with a Reynolds Averaged Navier-Stokes (RANS) solver such that the thrust and power are simulated. The design variables are the shape parameters comprising the chord, the twist and the relative thickness of the wind turbine rotor blade. The comparative aerodynamic performance is analyzed between the original and optimized reference wind turbine rotor. The results showed that the optimization framework can be effectively and accurately utilized in enhancing the aerodynamic performance of the wind turbine rotor.

Land-Based Wind Turbine Transportation and Logistics Barriers and Their Effects on U.S. Wind Markets (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cotrell, J.; Stehly, T.; Johnson, J.

The average size of land based wind turbines installed in the United States has increased dramatically over time. As a result wind turbines are facing new transportation and logistics barriers that limit the size of utility scale land based wind turbines that can be deployed in the United States. Addressing these transportation and logistics barriers will allow for even further increases in U.S. turbine size using technologies under development for offshore markets. These barriers are important because larger taller turbines have been identified as a path to reducing the levelized cost of energy for electricity. Additionally, increases in turbine sizemore » enable the development of new low and moderate speed markets in the U.S. In turn, wind industry stakeholder support, market stability, and ultimately domestic content and manufacturing competitiveness are potentially affected. In general there is very little recent literature that characterizes transportation and logistics barriers and their effects on U.S. wind markets and opportunities. Accordingly, the objective of this paper is to report the results of a recent NREL study that identifies the barriers, assesses their impact and provides recommendations for strategies and specific actions.« less

Evaluating Tilt for Wind Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Annoni, Jennifer; Scholbrock, Andrew K.; Churchfield, Matthew J.

The objective of this work is to demonstrate the feasibility of tilt in a wind plant. Tilt control, much like other wind plant control strategies, has the potential to improve the performance of a wind plant. Tilt control uses the tilt angle of the turbine to direct the wake above or below the downstream turbines. This paper presents a study of tilt in two- and three-turbine arrays. Specifically, the authors show that the power production of a two-turbine array can be increased by tilting turbines in a specific orientation. When adding more turbines, as is shown with the three-turbine array,more » the overall percentage of power gain increases. This outcome deviates from some of the results seen in typical wind plant control strategies. Finally, we discuss the impact this type of control strategy has on the aerodynamics in a wind plant. This analysis demonstrates that a good understanding of wake characteristics is necessary to improve the plant's performance. A tilt strategy such as the one presented in this paper may have implications for future control/optimization studies including optimization of hub heights in a wind plant and analysis of deep array effects.« less

Towards reduced order modelling for predicting the dynamics of coherent vorticity structures within wind turbine wakes

NASA Astrophysics Data System (ADS)

Debnath, M.; Santoni, C.; Leonardi, S.; Iungo, G. V.

2017-03-01

The dynamics of the velocity field resulting from the interaction between the atmospheric boundary layer and a wind turbine array can affect significantly the performance of a wind power plant and the durability of wind turbines. In this work, dynamics in wind turbine wakes and instabilities of helicoidal tip vortices are detected and characterized through modal decomposition techniques. The dataset under examination consists of snapshots of the velocity field obtained from large-eddy simulations (LES) of an isolated wind turbine, for which aerodynamic forcing exerted by the turbine blades on the atmospheric boundary layer is mimicked through the actuator line model. Particular attention is paid to the interaction between the downstream evolution of the helicoidal tip vortices and the alternate vortex shedding from the turbine tower. The LES dataset is interrogated through different modal decomposition techniques, such as proper orthogonal decomposition and dynamic mode decomposition. The dominant wake dynamics are selected for the formulation of a reduced order model, which consists in a linear time-marching algorithm where temporal evolution of flow dynamics is obtained from the previous temporal realization multiplied by a time-invariant operator. This article is part of the themed issue 'Wind energy in complex terrains'.

Impact of wind turbine noise in the Netherlands.

PubMed

Verheijen, Edwin; Jabben, Jan; Schreurs, Eric; Smith, Kevin B

2011-01-01

The Dutch government aims at an increase of wind energy up to 6 000 MW in 2020 by placing new wind turbines on land or offshore. At the same time, the existing noise legislation for wind turbines is being reconsidered. For the purpose of establishing a new noise reception limit value expressed in L den , the impact of wind turbine noise under the given policy targets needs to be explored. For this purpose, the consequences of different reception limit values for the new Dutch noise legislation have been studied, both in terms of effects on the population and regarding sustainable energy policy targets. On the basis of a nation-wide noise map containing all wind turbines in The Netherlands, it is calculated that 3% of the inhabitants of The Netherlands are currently exposed to noise from wind turbines above 28 dB(A) at the faηade. Newly established dose-response relationships indicate that about 1500 of these inhabitants are likely to be severely annoyed inside their dwellings. The available space for new wind turbines strongly depends on the noise limit value that will be chosen. This study suggests an outdoor A-weighted reception limit of L den = 45 dB as a trade-off between the need for protection against noise annoyance and the feasibility of national targets for renewable energy.

Experimental Investigation of Very Large Model Wind Turbine Arrays

NASA Astrophysics Data System (ADS)

Charmanski, Kyle; Wosnik, Martin

2013-11-01

The decrease in energy yield in large wind farms (array losses) and associated revenue losses can be significant. When arrays are sufficiently large they can reach what is known as a fully developed wind turbine array boundary layer, or fully developed wind farm condition. This occurs when the turbulence statistics and the structure of the turbulence, within and above a wind farm, as well as the performance of the turbines remain the same from one row to the next. The study of this condition and how it is affected by parameters such as turbine spacing, power extraction, tip speed ratio, etc. is important for the optimization of large wind farms. An experimental investigation of the fully developed wind farm condition was conducted using a large array of porous disks (upstream) and realistically scaled 3-bladed wind turbines with a diameter of 0.25m. The turbines and porous disks were placed inside a naturally grown turbulent boundary layer in the 6m × 2.5m × 72m test section of the UNH Flow Physics Facility which can achieve test section velocities of up to 14 m/s and Reynolds numbers δ+ = δuτ / ν ~ 20 , 000 . Power, rate of rotation and rotor thrust were measured for select turbines, and hot-wire anemometry was used for flow measurements.

Wind tunnel measurements of wake structure and wind farm power for actuator disk model wind turbines in yaw

NASA Astrophysics Data System (ADS)

Howland, Michael; Bossuyt, Juliaan; Kang, Justin; Meyers, Johan; Meneveau, Charles

2016-11-01

Reducing wake losses in wind farms by deflecting the wakes through turbine yawing has been shown to be a feasible wind farm control approach. In this work, the deflection and morphology of wakes behind a wind turbine operating in yawed conditions are studied using wind tunnel experiments of a wind turbine modeled as a porous disk in a uniform inflow. First, by measuring velocity distributions at various downstream positions and comparing with prior studies, we confirm that the nonrotating wind turbine model in yaw generates realistic wake deflections. Second, we characterize the wake shape and make observations of what is termed a "curled wake," displaying significant spanwise asymmetry. Through the use of a 100 porous disk micro-wind farm, total wind farm power output is studied for a variety of yaw configurations. Strain gages on the tower of the porous disk models are used to measure the thrust force as a substitute for turbine power. The frequency response of these measurements goes up to the natural frequency of the model and allows studying the spatiotemporal characteristics of the power output under the effects of yawing. This work has been funded by the National Science Foundation (Grants CBET-113380 and IIA-1243482, the WINDINSPIRE project). JB and JM are supported by ERC (ActiveWindFarms, Grant No. 306471).

77 FR 46034 - Utility Scale Wind Towers From the People's Republic of China: Preliminary Determination of Sales...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-02

... nacelle and rotor blades in a wind turbine with a minimum rated electrical power generation capacity in... efficiencies have been improving, and turbine heights have been rising to altitudes with much stronger winds... configurations that meet the minimum height requirement and are designed to support wind turbine electrical...

76 FR 61735 - Incidental Take Permit; Auwahi Wind Energy Generation Facility, Maui, HI; Draft Habitat...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-05

.... The proposed facility will consist of eight wind turbine generators (WTGs), a maintenance building, an... indicates that the Hawaiian hoary bat flies in the area proposed for wind turbine development, and that the... Hawaiian hoary bat are known to have collided with the existing wind turbine structures at the 30- megawatt...

Wind Plant Power Optimization and Control under Uncertainty

NASA Astrophysics Data System (ADS)

Jha, Pankaj; Ulker, Demet; Hutchings, Kyle; Oxley, Gregory

2017-11-01

The development of optimized cooperative wind plant control involves the coordinated operation of individual turbines co-located within a wind plant to improve the overall power production. This is typically achieved by manipulating the trajectory and intensity of wake interactions between nearby turbines, thereby reducing wake losses. However, there are various types of uncertainties involved, such as turbulent inflow and microscale and turbine model input parameters. In a recent NREL-Envision collaboration, a controller that performs wake steering was designed and implemented for the Longyuan Rudong offshore wind plant in Jiangsu, China. The Rudong site contains 25 Envision EN136-4 MW turbines, of which a subset was selected for the field test campaign consisting of the front two rows for the northeasterly wind direction. In the first row, a turbine was selected as the reference turbine, providing comparison power data, while another was selected as the controlled turbine. This controlled turbine wakes three different turbines in the second row depending on the wind direction. A yaw misalignment strategy was designed using Envision's GWCFD, a multi-fidelity plant-scale CFD tool based on SOWFA with a generalized actuator disc (GAD) turbine model, which, in turn, was used to tune NREL's FLORIS model used for wake steering and yaw control optimization. The presentation will account for some associated uncertainties, such as those in atmospheric turbulence and wake profile.

Design of airborne wind turbine and computational fluid dynamics analysis

NASA Astrophysics Data System (ADS)

Anbreen, Faiqa

Wind energy is a promising alternative to the depleting non-renewable sources. The height of the wind turbines becomes a constraint to their efficiency. Airborne wind turbine can reach much higher altitudes and produce higher power due to high wind velocity and energy density. The focus of this thesis is to design a shrouded airborne wind turbine, capable to generate 70 kW to propel a leisure boat with a capacity of 8-10 passengers. The idea of designing an airborne turbine is to take the advantage of higher velocities in the atmosphere. The Solidworks model has been analyzed numerically using Computational Fluid Dynamics (CFD) software StarCCM+. The Unsteady Reynolds Averaged Navier Stokes Simulation (URANS) with K-epsilon turbulence model has been selected, to study the physical properties of the flow, with emphasis on the performance of the turbine and the increase in air velocity at the throat. The analysis has been done using two ambient velocities of 12 m/s and 6 m/s. At 12 m/s inlet velocity, the velocity of air at the turbine has been recorded as 16 m/s. The power generated by the turbine is 61 kW. At inlet velocity of 6 m/s, the velocity of air at turbine increased to 10 m/s. The power generated by turbine is 25 kW.

Identification of wind turbine testing practices and investigation of the performance benefits of closely-spaced lateral wind farm configurations

NASA Astrophysics Data System (ADS)

McTavish, Sean

The current thesis investigates the development of guidelines for testing small-scale wind turbines and identifies a method that can be used to increase the performance of wind farms. The research was conducted using two scaled wind turbine designs. The first design was a three-bladed wind turbine designed in the Department of Mechanical and Aerospace Engineering (MAAE) to operate in a low Reynolds number regime and to generate a thrust coefficient representative of commercial-scale wind turbines. An Eppler E387 airfoil was selected for the wind turbine due to its behaviour at low Reynolds numbers and the chord of the turbine was increased relative to full-scale designs in order to increase the range of Reynolds numbers that could be attained. The second design was a geometrically-scaled version of an existing two-bladed wind turbine with a NACA 0012 airfoil that was originally designed at the Delft University of Technology. Experiments were conducted in a 0.61 m x 0.81 m water channel in order to independently evaluate the effects of increasing blockage and Reynolds number on the development of the wind turbine wake. Quantitative dye visualisation was used to identify the position of tip vortex cores relative to the blade tip in order to assess how blockage and Reynolds number effects modified the initial expansion in the near wake. Blockage effects on the wake development were assessed using five wind turbines with diameters ranging from 20 cm to 40 cm, corresponding to blockage of 6.3% to 25.4%. The rotors were all operated at a similar tip speed ratio of 6 and a Reynolds number of 23,000 based on the blade tip speed and tip chord. One Outcome of the research was the identification of a limit beyond which blockage narrowed the expansion in the near wake of a wind turbine. It was observed that blockage should be maintained at less than 10% in order to prevent the wake from narrowing artificially due to the flow acceleration around the turbine caused by excessive blockage. The experimental results were compared to a freestream computational simulation of the same turbine using the vortex particle method code GENUVP. The magnitude of the wake expansion in the freestream computation was similar to the experimental wake expansion observed with 6.3% and 9.9% blockage. Following the identification of testing practices related to blockage, the effect of the Reynolds number on the development of the initial wake expansion was investigated using two different rotors. The wake expansion downstream of a 25 cm diameter, three-bladed MAAE wind turbine became less sensitive to the Reynolds number above a Reynolds number of 20,000. This behaviour may be related to the laminar-to-turbulent transition behaviour of the E387 airfoil on the rotor blades. The wake downstream of the geometrically-scaled rotor was found to be 40% to 60% narrower than the initial wake expansion downstream of the corresponding medium-scale rotor. The work identified the need to develop a wind turbine design for a particular Reynolds number regime as opposed to merely geometrically-scaling a turbine. The performance of scaled wind farm configurations was then evaluated using 20 cm diameter MAAE wind turbines installed in the 1.68 m x 1.12 m atmospheric boundary layer wind tunnel at Carleton University. A scaled boundary layer was generated using triangular boundary layer spires and roughness elements installed along the upstream fetch of the tunnel. Each wind turbine was outfitted with a DC generator and the power output generated by the scaled turbines was used to characterise their performance. A single-normal hot-wire probe was used to determine the mean speed profiles in the fiowfield. Two laterally-aligned wind turbines were separated by a gap and it was observed that when the gap was less than 3 diameters (D), the speed of the flow between the rotors was increased from the rotor plane to approximately 2.5D downstream. This behaviour was identified as an in-field blockage effect and is analogous to the increase in wind speed caused by blockage in a closed test section. The increased flow speed was associated with a narrowing of the wake between the closely-spaced rotors and the concept of capitalising on this in-field blockage effect using a third, offset rotor was investigated. Performance measurements were conducted using 3 gap widths between the outer two turbines and a third, central turbine was placed at 9 different downstream positions. The middle turbine experienced an increase in power when placed within 2.5D of the upstream rotor plane due to the increase in speed in this region. This approach to planning wind farms will help to limit power losses due to downstream wake effects while providing an increase in power output at mean annual wind speeds.

Small Wind Research Turbine: Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Corbus, D.; Meadors, M.

2005-10-01

The Small Wind Research Turbine (SWRT) project was initiated to provide reliable test data for model validation of furling wind turbines and to help understand small wind turbine loads. This report will familiarize the user with the scope of the SWRT test and support the use of these data. In addition to describing all the testing details and results, the report presents an analysis of the test data and compares the SWRT test data to simulation results from the FAST aeroelastic simulation model.

An Analysis of the Use of Energy Audits, Solar Panels, and Wind Turbines to Reduce Energy Consumption from Non Renewable Energy Sources

DTIC Science & Technology

2015-04-15

the Use of Energy Audits, Solar Panels, and Wind Turbines to Reduce Energy Consumption from Non Renewable Energy Sources Energy is a National...Park, NC 27709-2211 Energy Audits, Energy Conservation, Renewable Energy, Solar Energy, Wind Turbine Use, Energy Consumption REPORT DOCUMENTATION PAGE 11...in non peer-reviewed journals: An Analysis of the Use of Energy Audits, Solar Panels, and Wind Turbines to Reduce Energy Consumption from Non

Method for determining how to operate and control wind turbine arrays in utility systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Javid, S.H.; Hauth, R.L.; Younkins, T.D.

1984-01-01

A method for determining how utility wind turbine arrays should be controlled and operated on the load frequency control time-scale is presented. Initial considerations for setting wind turbine control requirements are followed by a description of open loop operation and of closed loop and feed forward wind turbine array control concepts. The impact of variations in array output on meeting minimum criteria are developed. The method for determining the required control functions is then presented and results are tabulated. (LEW)

Utility interconnection issues for wind power generation

NASA Technical Reports Server (NTRS)

Herrera, J. I.; Lawler, J. S.; Reddoch, T. W.; Sullivan, R. L.

1986-01-01

This document organizes the total range of utility related issues, reviews wind turbine control and dynamic characteristics, identifies the interaction of wind turbines to electric utility systems, and identifies areas for future research. The material is organized at three levels: the wind turbine, its controls and characteristics; connection strategies as dispersed or WPSs; and the composite issue of planning and operating the electric power system with wind generated electricity.

Evaluation of lightning accommodation systems for wind-driven turbine rotors

NASA Technical Reports Server (NTRS)

Bankaitis, H.

1982-01-01

Wind-driven turbine generators are being evaluated as an alternative source of electric energy. Areas of favorable location for the wind-driven turbines (high wind density) coincide with areas of high incidence of thunderstorm activity. These locations, coupled with the 30-m or larger diameter rotor blades, make the wind-driven turbine blades probable terminations for lightning strikes. Several candidate systems of lightning accommodation for composite-structural-material blades were designed and their effectiveness evaluated by submitting the systems to simulated lightning strikes. The test data were analyzed and system design were reviewed on the basis of the analysis.

Study on Determination Method of Fatigue Testing Load for Wind Turbine Blade

NASA Astrophysics Data System (ADS)

Liao, Gaohua; Wu, Jianzhong

2017-07-01

In this paper, the load calculation method of the fatigue test was studied for the wind turbine blade under uniaxial loading. The characteristics of wind load and blade equivalent load were analyzed. The fatigue property and damage theory of blade material were studied. The fatigue load for 2MW blade was calculated by Bladed, and the stress calculated by ANSYS. Goodman modified exponential function S-N curve and linear cumulative damage rule were used to calculate the fatigue load of wind turbine blades. It lays the foundation for the design and experiment of wind turbine blade fatigue loading system.

Wind turbine acoustics

NASA Technical Reports Server (NTRS)

Hubbard, Harvey H.; Shepherd, Kevin P.

1990-01-01

Available information on the physical characteristics of the noise generated by wind turbines is summarized, with example sound pressure time histories, narrow- and broadband frequency spectra, and noise radiation patterns. Reviewed are noise measurement standards, analysis technology, and a method of characterizing wind turbine noise. Prediction methods are given for both low-frequency rotational harmonics and broadband noise components. Also included are atmospheric propagation data showing the effects of distance and refraction by wind shear. Human perception thresholds, based on laboratory and field tests, are given. Building vibration analysis methods are summarized. The bibliography of this report lists technical publications on all aspects of wind turbine acoustics.

Wind Turbines Adaptation to the Variability of the Wind Field

NASA Astrophysics Data System (ADS)

Ulianov, Yuriy; Martynenko, Gennadii; Misaylov, Vitaliy; Soliannikova, Iuliia

2010-05-01

WIND TURBINES ADAPTATION TO THE VARIABILITY OF THE WIND FIELD The subject of our scientific research is wind power turbines (WPT) with the horizontal axis which were now common in the world. Efficient wind turbines work is largely determined by non-stationarity of the wind field, expressed in its gustiness, the presence of vertical and horizontal shifts of wind speed and direction. At critical values of the wind parameters WPT has aerodynamic and mechanical overload, leading to breakdowns, premature wear and reduce the life of the wind turbine. To prevent accidents at the peak values of wind speed it is used the regulatory system of windwheels. WPT control systems provide a process orientation of the wind turbine rotor axis in the line of the mean wind. Wind turbines are also equipped with braking device used to protect against breakdowns when a significant increase in the wind. In general, all these methods of regulation are not always effective. Thus, in practice there may be situations when the wind speed is many times greater than the stated limit. For example, if there are microbursts in the atmospheric boundary layer, low-level wind shears caused by its gust front, storms, etc. It is required for a wind power turbine adaptation to intensive short-term wind impulses and considerable vertical wind shifts that the data about them shall be obtained ahead of time. To do this it is necessary to have the information on the real structure of the wind field in the area of the blade sweep for the minimum range against the wind that is determined by the mean speed and the system action time. The implementation of acoustic and laser traditional wind sounding systems is limited by ambient acoustic noise, by heavy rain, snowfall and by fog. There are free of these disadvantages the inclined radioacoustic sounding (IRASS) technique which works for a system of remote detection and control of wind gusts. IRASS technique is realized as low-potential Doppler pulse radar including combined RF-acoustic antenna installed coaxially with the gondola of the wind power turbine. The work of the technique is synchronized with rotation of blades to eliminate their shielding action. Dangerous in terms of dynamic strength is the wind load pulse, the rise time which is comparable with the period of the natural frequency of the wind turbine elements (blade, tower, rotor, etc.). The amplitude decay of resonant vibrations at critical values of the speed of rotation can be realized through the use of mechanical elastic supports with nonlinear artificial dampers. They have a high coefficient of resistance, but may cause self-excited oscillations. We propose the way to deal with raised vibration of wind turbine elements at the expense of short-term increase of damping in the range of critical rotary axis speeds or during impulsive effects of wind loadings (wind gusts). This is possible through the use of non-linear electromagnetic dampers or active magnetic bearings. Their feature is the possibility of varying the mechanical stiffness and damping properties by changing the electrical parameters of electromagnets. The controlling of these parameters is carried out by the control system (CS) with the information feedback on the spatial-temporal structure of the wind field obtained from IRASS. In the composition of the CS can also be included the rotational speed sensor of the WPT rotor. This approach to the adaptation of wind turbines will allow to reduce vibration and to perform early compensation of the load on their components, which arise under the wind gusts. In addition, corrections about the wind field obtained with IRASS, would increase the mean power of WPT.

Inverse load calculation procedure for offshore wind turbines and application to a 5-MW wind turbine support structure: Inverse load calculation procedure for offshore wind turbines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pahn, T.; Rolfes, R.; Jonkman, J.

A significant number of wind turbines installed today have reached their designed service life of 20 years, and the number will rise continuously. Most of these turbines promise a more economical performance if they operate for more than 20 years. To assess a continued operation, we have to analyze the load-bearing capacity of the support structure with respect to site-specific conditions. Such an analysis requires the comparison of the loads used for the design of the support structure with the actual loads experienced. This publication presents the application of a so-called inverse load calculation to a 5-MW wind turbine supportmore » structure. The inverse load calculation determines external loads derived from a mechanical description of the support structure and from measured structural responses. Using numerical simulations with the software fast, we investigated the influence of wind-turbine-specific effects such as the wind turbine control or the dynamic interaction between the loads and the support structure to the presented inverse load calculation procedure. fast is used to study the inverse calculation of simultaneously acting wind and wave loads, which has not been carried out until now. Furthermore, the application of the inverse load calculation procedure to a real 5-MW wind turbine support structure is demonstrated. In terms of this practical application, setting up the mechanical system for the support structure using measurement data is discussed. The paper presents results for defined load cases and assesses the accuracy of the inversely derived dynamic loads for both the simulations and the practical application.« less

Simulation Comparison of Wake Mitigation Control Strategies for a Two-Turbine Case

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleming, Paul; Gebraad, Pieter M. O.; Lee, Sang

2015-12-01

Wind turbines arranged in a wind plant impact each other through their wakes. Wind plant control is an active research field that attempts to improve wind plant performance by coordinating control of individual turbines to take into account these turbine–wake interactions. High-fidelity simulations of a two-turbine fully waked scenario are used to investigate several wake mitigation strategies, in this paper, including modification of yaw and tilt angles of an upstream turbine to induce wake skew, as well as repositioning of the downstream turbine. The simulation results are compared through change relative to a baseline operation in terms of overall powermore » capture and loading on the upstream and downstream turbine. Results demonstrated improved power production for all methods. Moreover, analysis of control options, including individual pitch control, shows potential to minimize the increase of, or even reduce, turbine loads.« less

Wind and turbine characteristics needed for integration of wind turbine arrays into a utility system

NASA Technical Reports Server (NTRS)

Park, G. L.

1982-01-01

Wind data and wind turbine generator (WTG) performance characteristics are often available in a form inconvenient for use by utility planners and engineers. The steps used by utility planners are summarized and the type of wind and WTG data needed for integration of WTG arrays suggested. These included long term yearly velocity averages for preliminary site feasibility, hourly velocities on a 'wind season' basis for more detailed economic analysis and for reliability studies, worst-case velocity profiles for gusts, and various minute-to-hourly velocity profiles for estimating the effect of longer-term wind fluctuations on utility operations. wind turbine data needed includes electrical properties of the generator, startup and shutdown characteristics, protection characteristics, pitch control response and control strategy, and electro-mechanical model for stability analysis.

Operational results for the experimental DOE/NASA Mod-OA wind turbine project

NASA Astrophysics Data System (ADS)

Shaltens, R. K.; Birchenough, A. G.

The Mod-OA wind turbine project which was to gain early experience in the operation of large wind turbines in a utility environment is discussed. The Mod-OA wind turbines were a first generation design, and even though not cost effective, the operating experience and performance characteristics had a significant effect on the design and development of the second and third generation machines. The Mod-OA machines were modified as a result of the operational experience, particularly the blade development and control system strategy. The results of study to investigate the interaction of a Mod-OA wind turbine with an isolated diesel generation system are discussed. The machine configuration, its advantages and disadvantages and the machine performance and availability are discussed.

Operational results for the experimental DOE/NASA Mod-OA wind turbine project

NASA Technical Reports Server (NTRS)

Shaltens, R. K.; Birchenough, A. G.

1983-01-01

The Mod-OA wind turbine project which was to gain early experience in the operation of large wind turbines in a utility environment is discussed. The Mod-OA wind turbines were a first generation design, and even though not cost effective, the operating experience and performance characteristics had a significant effect on the design and development of the second and third generation machines. The Mod-OA machines were modified as a result of the operational experience, particularly the blade development and control system strategy. The results of study to investigate the interaction of a Mod-OA wind turbine with an isolated diesel generation system are discussed. The machine configuration, its advantages and disadvantages and the machine performance and availability are discussed.

Computational Acoustic Beamforming for Noise Source Identification for Small Wind Turbines

PubMed Central

Lien, Fue-Sang

2017-01-01

This paper develops a computational acoustic beamforming (CAB) methodology for identification of sources of small wind turbine noise. This methodology is validated using the case of the NACA 0012 airfoil trailing edge noise. For this validation case, the predicted acoustic maps were in excellent conformance with the results of the measurements obtained from the acoustic beamforming experiment. Following this validation study, the CAB methodology was applied to the identification of noise sources generated by a commercial small wind turbine. The simulated acoustic maps revealed that the blade tower interaction and the wind turbine nacelle were the two primary mechanisms for sound generation for this small wind turbine at frequencies between 100 and 630 Hz. PMID:28378012

BeamDyn: A High-Fidelity Wind Turbine Blade Solver in the FAST Modular Framework: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Q.; Sprague, M.; Jonkman, J.

2015-01-01

BeamDyn, a Legendre-spectral-finite-element implementation of geometrically exact beam theory (GEBT), was developed to meet the design challenges associated with highly flexible composite wind turbine blades. In this paper, the governing equations of GEBT are reformulated into a nonlinear state-space form to support its coupling within the modular framework of the FAST wind turbine computer-aided engineering (CAE) tool. Different time integration schemes (implicit and explicit) were implemented and examined for wind turbine analysis. Numerical examples are presented to demonstrate the capability of this new beam solver. An example analysis of a realistic wind turbine blade, the CX-100, is also presented asmore » validation.« less

Comparing model-based predictions of a wind turbine wake to LiDAR measurements in complex terrain

NASA Astrophysics Data System (ADS)

Kay, Andrew; Jones, Paddy; Boyce, Dean; Bowman, Neil

2013-04-01

The application of remote sensing techniques to the measurement of wind characteristics offers great potential to accurately predict the atmospheric boundary layer flow (ABL) and its interactions with wind turbines. An understanding of these interactions is important for optimizing turbine siting in wind farms and improving the power performance and lifetime of individual machines. In particular, Doppler wind Light Detection and Ranging (LiDAR) can be used to remotely measure the wind characteristics (speed, direction and turbulence intensity) approaching a rotor. This information can be utilised to improve turbine lifetime (advanced detection of incoming wind shear, wind veer and extreme wind conditions, such as gusts) and optimise power production (improved yaw, pitch and speed control). LiDAR can also make detailed measurements of the disturbed wind profile in the wake, which can damage surrounding turbines and reduce efficiency. These observational techniques can help engineers better understand and model wakes to optimize turbine spacing in large wind farms, improving efficiency and reducing the cost of energy. NEL is currently undertaking research to measure the disturbed wind profile in the wake of a 950 kW wind turbine using a ZephIR Dual Mode LiDAR at its Myres Hill wind turbine test site located near Glasgow, Scotland. Myres Hill is moderately complex terrain comprising deep peat, low lying grass and heathers, localised slopes and nearby forest, approximately 2 km away. Measurements have been obtained by vertically scanning at 10 recorded heights across and above the rotor plane to determine the wind speed, wind direction and turbulence intensity profiles. Measurement stations located at various rotor diameters downstream of the turbine were selected in an attempt to capture the development of the wake and its recovery towards free stream conditions. Results of the measurement campaign will also highlight how the wake behaves as a result of sudden gusts or rapid changes in wind direction. NEL has carried out simulations to model the wake of the turbine using Computational Fluid Dynamics (CFD) software provided by ANSYS Inc. The model incorporates a simple actuator disk concept to model the turbine and its wake, typical of that used in many commercial wind farm optimization tools. The surrounding terrain, including the forestry is modelled allowing an investigation of the wake-terrain interactions occurring across the site. The overall aim is to compare the LiDAR measurements with simulated data to assess the quality of the model and its sensitivity to variables such as mesh size and turbulence/forestry modelling techniques. Knowledge acquired from the study will help to define techniques for combining LiDAR measurements with CFD modelling to improve predictions of wake losses in large wind farms and hence, energy production. In addition, the impact of transient wind conditions on the results of predictions based on idealised, steady state models has been examined.

Wind tunnel testing of 5-bladed H-rotor wind turbine with the integration of the omni-direction-guide-vane

NASA Astrophysics Data System (ADS)

Fazlizan, A.; Chong, W. T.; Omar, W. Z. W.; Mansor, S.; Zain, Z. M.; Pan, K. C.; Oon, C. S.

2012-06-01

A novel omni-direction-guide-vane (ODGV) that surrounds a vertical axis wind turbine (VAWT) is designed to improve the wind turbine performance by increasing the oncoming wind speed and guiding the wind-stream through optimum flow angles before impinging onto the turbine blades. Wind tunnel testing was performed to measure the performance of a 5-bladed H-rotor wind turbine with Wortmann FX63-137 airfoil blades, with and without the integration of the ODGV. The test was conducted using a scaled model turbine which was constructed to simulate the VAWT enclosed by the ODGV on a building. The diameter and height of the ODGV are 2 times larger than the VAWT's. Torque, rotational speed and power measurements were performed by using torque transducer with hysteresis brake applied to the rotor shaft. The VAWT shows an improvement on its self-starting behavior where the cut-in speed reduced to 4 m/s with the ODGV (7.35 m/s without the ODGV). Since the VAWT is able to self-start at lower wind speed, the working hour of the wind turbine would increase. At the wind speed of 6 m/s and free-running condition (only rotor inertia and bearing friction were applied), the ODGV helps to increase the rotor RPM by 182%. At the same wind speed (6 m/s), the ODGV helps to increase the power output by 3.48 times at peak torque. With this innovative design, the size of VAWT can be reduced for a given power output and should generate interest in the market, even for regions with weaker winds.

Analysis of conditions favourable for small vertical axis wind turbines between building passages in urban areas of Sweden

NASA Astrophysics Data System (ADS)

Awan, Muhammad Rizwan; Riaz, Fahid; Nabi, Zahid

2017-05-01

This paper presents the analysis of installing the vertical axis wind turbines between the building passages on an island in Stockholm, Sweden. Based on the idea of wind speed amplification due to the venture effect in passages, practical measurements were carried out to study the wind profile for a range of passage widths in parallel building passages. Highest increment in wind speed was observed in building passages located on the periphery of sland as wind enters from free field. Wind mapping was performed in the island to choose the most favourable location to install the vertical axis wind turbines (VAWT). Using the annual wind speed data for location and measured amplification factor, energy potential of the street was calculated. This analysis verified that small vertical axis wind turbines can be installed in the passage centre line provided that enough space is provided for traffic and passengers.

Analytical expressions for maximum wind turbine average power in a Rayleigh wind regime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlin, P.W.

Average or expectation values for annual power of a wind turbine in a Rayleigh wind regime are calculated and plotted as a function of cut-out wind speed. This wind speed is expressed in multiples of the annual average wind speed at the turbine installation site. To provide a common basis for comparison of all real and imagined turbines, the Rayleigh-Betz wind machine is postulated. This machine is an ideal wind machine operating with the ideal Betz power coefficient of 0.593 in a Rayleigh probability wind regime. All other average annual powers are expressed in fractions of that power. Cases consideredmore » include: (1) an ideal machine with finite power and finite cutout speed, (2) real machines operating in variable speed mode at their maximum power coefficient, and (3) real machines operating at constant speed.« less

Analysis of the Flicker Level Produced by a Fixed-Speed Wind Turbine

NASA Astrophysics Data System (ADS)

Suppioni, Vinicius; P. Grilo, Ahda

2013-10-01

In this article, the analysis of the flicker emission during continuous operation of a mid-scale fixed-speed wind turbine connected to a distribution system is presented. Flicker emission is investigated based on simulation results, and the dependence of flicker emission on short-circuit capacity, grid impedance angle, mean wind speed, and wind turbulence is analyzed. The simulations were conducted in different programs in order to provide a more realistic wind emulation and detailed model of mechanical and electrical components of the wind turbine. Such aim is accomplished by using FAST (Fatigue, Aerodynamics, Structures, and Turbulence) to simulate the mechanical parts of the wind turbine, Simulink/MatLab to simulate the electrical system, and TurbSim to obtain the wind model. The results show that, even for a small wind generator, the flicker level can limit the wind power capacity installed in a distribution system.

Real Time Location of Targets in Cluttered Environments

DTIC Science & Technology

2014-03-13

7 Return Signal computation from a single wind turbine ...7 Return Signal From Multiple Wind Turbines With and Without Aircraft...signals to the far field. 2. Validated using analytical signals. 3. Inner field scattering from a wind turbine and aircraft is computed 4. An

78 FR 73704 - Eagle Permits; Changes in the Regulations Governing Eagle Permitting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-09

... to an otherwise lawful activity, such as mortalities caused by collisions with wind turbines... birds, specifically raptors, are especially vulnerable to colliding with wind turbines (Barrios and... interactions with power lines, wind turbines, or other infrastructure. APPs are developed by companies...

75 FR 60102 - South Dakota PrairieWinds Project (DOE/EIS-0418)

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-29

... feature 101 wind turbine generators; 6,000 square-foot operations and maintenance building and fence... generation facility that would feature 101 wind turbine generators; 6,000 square-foot operations and... turbine generators, operations and maintenance building and fence perimeter, underground communication...

Industrial wind turbines and adverse health effects.

PubMed

Jeffery, Roy D; Krogh, Carmen M E; Horner, Brett

2014-01-01

Some people living in the environs of industrial wind turbines (IWTs) report experiencing adverse health and socioeconomic effects. This review considers the hypothesis that annoyance from audible IWTs is the cause of these adverse health effects. We searched PubMed and Google Scholar for articles published since 2000 that included the terms "wind turbine health," "wind turbine infrasound," "wind turbine annoyance," "noise annoyance" or "low frequency noise" in the title or abstract. Industrial wind turbines produce sound that is perceived to be more annoying than other sources of sound. Reported effects from exposure to IWTs are consistent with well-known stress effects from persistent unwanted sound. If placed too close to residents, IWTs can negatively affect the physical, mental and social well-being of people. There is sufficient evidence to support the conclusion that noise from audible IWTs is a potential cause of health effects. Inaudible low-frequency noise and infrasound from IWTs cannot be ruled out as plausible causes of health effects.

Finite element methods in a simulation code for offshore wind turbines

NASA Astrophysics Data System (ADS)

Kurz, Wolfgang

1994-06-01

Offshore installation of wind turbines will become important for electricity supply in future. Wind conditions above sea are more favorable than on land and appropriate locations on land are limited and restricted. The dynamic behavior of advanced wind turbines is investigated with digital simulations to reduce time and cost in development and design phase. A wind turbine can be described and simulated as a multi-body system containing rigid and flexible bodies. Simulation of the non-linear motion of such a mechanical system using a multi-body system code is much faster than using a finite element code. However, a modal representation of the deformation field has to be incorporated in the multi-body system approach. The equations of motion of flexible bodies due to deformation are generated by finite element calculations. At Delft University of Technology the simulation code DUWECS has been developed which simulates the non-linear behavior of wind turbines in time domain. The wind turbine is divided in subcomponents which are represented by modules (e.g. rotor, tower etc.).

Floating wind turbine system

NASA Technical Reports Server (NTRS)

Viterna, Larry A. (Inventor)

2009-01-01

A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.

Distributed Wind Competitiveness Improvement Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

The Competitiveness Improvement Project (CIP) is a periodic solicitation through the U.S. Department of Energy and its National Renewable Energy Laboratory. The Competitiveness Improvement Project (CIP) is a periodic solicitation through the U.S. Department of Energy and its National Renewable Energy Laboratory. Manufacturers of small and medium wind turbines are awarded cost-shared grants via a competitive process to optimize their designs, develop advanced manufacturing processes, and perform turbine testing. The goals of the CIP are to make wind energy cost competitive with other distributed generation technology and increase the number of wind turbine designs certified to national testing standards. Thismore » fact sheet describes the CIP and funding awarded as part of the project.ufacturers of small and medium wind turbines are awarded cost-shared grants via a competitive process to optimize their designs, develop advanced manufacturing processes, and perform turbine testing. The goals of the CIP are to make wind energy cost competitive with other distributed generation technology and increase the number of wind turbine designs certified to national testing standards. This fact sheet describes the CIP and funding awarded as part of the project.« less

Increasing power generation in horizontal axis wind turbines using optimized flow control

NASA Astrophysics Data System (ADS)

Cooney, John A., Jr.

In order to effectively realize future goals for wind energy, the efficiency of wind turbines must increase beyond existing technology. One direct method for achieving increased efficiency is by improving the individual power generation characteristics of horizontal axis wind turbines. The potential for additional improvement by traditional approaches is diminishing rapidly however. As a result, a research program was undertaken to assess the potential of using distributed flow control to increase power generation. The overall objective was the development of validated aerodynamic simulations and flow control approaches to improve wind turbine power generation characteristics. BEM analysis was conducted for a general set of wind turbine models encompassing last, current, and next generation designs. This analysis indicated that rotor lift control applied in Region II of the turbine power curve would produce a notable increase in annual power generated. This was achieved by optimizing induction factors along the rotor blade for maximum power generation. In order to demonstrate this approach and other advanced concepts, the University of Notre Dame established the Laboratory for Enhanced Wind Energy Design (eWiND). This initiative includes a fully instrumented meteorological tower and two pitch-controlled wind turbines. The wind turbines are representative in their design and operation to larger multi-megawatt turbines, but of a scale that allows rotors to be easily instrumented and replaced to explore new design concepts. Baseline data detailing typical site conditions and turbine operation is presented. To realize optimized performance, lift control systems were designed and evaluated in CFD simulations coupled with shape optimization tools. These were integrated into a systematic design methodology involving BEM simulations, CFD simulations and shape optimization, and selected experimental validation. To refine and illustrate the proposed design methodology, a complete design cycle was performed for the turbine model incorporated in the wind energy lab. Enhanced power generation was obtained through passive trailing edge shaping aimed at reaching lift and lift-to-drag goals predicted to optimize performance. These targets were determined by BEM analysis to improve power generation characteristics and annual energy production (AEP) for the wind turbine. A preliminary design was validated in wind tunnel experiments on a 2D rotor section in preparation for testing in the full atmospheric environment of the eWiND Laboratory. These tests were performed for the full-scale geometry and atmospheric conditions. Upon making additional improvements to the shape optimization tools, a series of trailing edge additions were designed to optimize power generation. The trailing edge additions were predicted to increase the AEP by up to 4.2% at the White Field site. The pieces were rapid-prototyped and installed on the wind turbine in March, 2014. Field tests are ongoing.

Review Report on Design Study and Economic Assessment of Multi-Unit Offshore Wind Energy Conversion Systems Applications,

DTIC Science & Technology

1977-03-21

meter turbine . Available from NTIS; $6.50. 113 pages. 7. SAND-76-0130 Wind Tunnel Performance Data for the Darrieus Wind Tur- bine with NACA-0012...2-meter-diameter Darrieus wind turbine have been tested in a low speed wind tunnel. The airfoil section for all configurations was NACA 0012. The... Darrieus Vertical-Axis Wind Turbine Program at Sandia Laboratories, Kadlec, E.G., published by Sandia Laboratories 1976. Contract No. AT(29-1)-789. From

Safety and Function Test Report for the Viryd CS8 Wind Turbine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roadman, J.; Murphy, M.; van Dam, J.

2013-10-01

This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. Several turbines were selected for testing at the National Wind Technology Center (NWTC) at the National Renewable Energy Laboratory (NREL) as a part of the Small Wind Turbine Independent Testing project. Safety and function testing is one of up to five tests that may be performed on the turbines. Other tests include duration, power performance, acoustic noise, and power quality. Viryd Technologies, Inc.more » of Austin, Texas, was the recipient of the DOE grant and provided the turbine for testing.« less

Behavior of bats at wind turbines

PubMed Central

Cryan, Paul. M.; Gorresen, P. Marcos; Hein, Cris D.; Schirmacher, Michael R.; Diehl, Robert H.; Huso, Manuela M.; Hayman, David T. S.; Fricker, Paul D.; Bonaccorso, Frank J.; Johnson, Douglas H.; Heist, Kevin; Dalton, David C.

2014-01-01

Wind turbines are causing unprecedented numbers of bat fatalities. Many fatalities involve tree-roosting bats, but reasons for this higher susceptibility remain unknown. To better understand behaviors associated with risk, we monitored bats at three experimentally manipulated wind turbines in Indiana, United States, from July 29 to October 1, 2012, using thermal cameras and other methods. We observed bats on 993 occasions and saw many behaviors, including close approaches, flight loops and dives, hovering, and chases. Most bats altered course toward turbines during observation. Based on these new observations, we tested the hypotheses that wind speed and blade rotation speed influenced the way that bats interacted with turbines. We found that bats were detected more frequently at lower wind speeds and typically approached turbines on the leeward (downwind) side. The proportion of leeward approaches increased with wind speed when blades were prevented from turning, yet decreased when blades could turn. Bats were observed more frequently at turbines on moonlit nights. Taken together, these observations suggest that bats may orient toward turbines by sensing air currents and using vision, and that air turbulence caused by fast-moving blades creates conditions that are less attractive to bats passing in close proximity. Tree bats may respond to streams of air flowing downwind from trees at night while searching for roosts, conspecifics, and nocturnal insect prey that could accumulate in such flows. Fatalities of tree bats at turbines may be the consequence of behaviors that evolved to provide selective advantages when elicited by tall trees, but are now maladaptive when elicited by wind turbines. PMID:25267628

Behavior of bats at wind turbines.

PubMed

Cryan, Paul M; Gorresen, P Marcos; Hein, Cris D; Schirmacher, Michael R; Diehl, Robert H; Huso, Manuela M; Hayman, David T S; Fricker, Paul D; Bonaccorso, Frank J; Johnson, Douglas H; Heist, Kevin; Dalton, David C

2014-10-21

Wind turbines are causing unprecedented numbers of bat fatalities. Many fatalities involve tree-roosting bats, but reasons for this higher susceptibility remain unknown. To better understand behaviors associated with risk, we monitored bats at three experimentally manipulated wind turbines in Indiana, United States, from July 29 to October 1, 2012, using thermal cameras and other methods. We observed bats on 993 occasions and saw many behaviors, including close approaches, flight loops and dives, hovering, and chases. Most bats altered course toward turbines during observation. Based on these new observations, we tested the hypotheses that wind speed and blade rotation speed influenced the way that bats interacted with turbines. We found that bats were detected more frequently at lower wind speeds and typically approached turbines on the leeward (downwind) side. The proportion of leeward approaches increased with wind speed when blades were prevented from turning, yet decreased when blades could turn. Bats were observed more frequently at turbines on moonlit nights. Taken together, these observations suggest that bats may orient toward turbines by sensing air currents and using vision, and that air turbulence caused by fast-moving blades creates conditions that are less attractive to bats passing in close proximity. Tree bats may respond to streams of air flowing downwind from trees at night while searching for roosts, conspecifics, and nocturnal insect prey that could accumulate in such flows. Fatalities of tree bats at turbines may be the consequence of behaviors that evolved to provide selective advantages when elicited by tall trees, but are now maladaptive when elicited by wind turbines.

Behavior of bats at wind turbines

USGS Publications Warehouse

Cryan, Paul M.; Gorresen, P. Marcos; Hine, Cris D.; Schirmacher, Michael; Diehl, Robert H.; Huso, Manuela M.; Hayman, David T.S.; Fricker, Paul D.; Bonaccorso, Frank J.; Johnson, Douglas H.; Heist, Kevin W.; Dalton, David C.

2014-01-01

Wind turbines are causing unprecedented numbers of bat fatalities. Many fatalities involve tree-roosting bats, but reasons for this higher susceptibility remain unknown. To better understand behaviors associated with risk, we monitored bats at three experimentally manipulated wind turbines in Indiana, United States, from July 29 to October 1, 2012, using thermal cameras and other methods. We observed bats on 993 occasions and saw many behaviors, including close approaches, flight loops and dives, hovering, and chases. Most bats altered course toward turbines during observation. Based on these new observations, we tested the hypotheses that wind speed and blade rotation speed influenced the way that bats interacted with turbines. We found that bats were detected more frequently at lower wind speeds and typically approached turbines on the leeward (downwind) side. The proportion of leeward approaches increased with wind speed when blades were prevented from turning, yet decreased when blades could turn. Bats were observed more frequently at turbines on moonlit nights. Taken together, these observations suggest that bats may orient toward turbines by sensing air currents and using vision, and that air turbulence caused by fast-moving blades creates conditions that are less attractive to bats passing in close proximity. Tree bats may respond to streams of air flowing downwind from trees at night while searching for roosts, conspecifics, and nocturnal insect prey that could accumulate in such flows. Fatalities of tree bats at turbines may be the consequence of behaviors that evolved to provide selective advantages when elicited by tall trees, but are now maladaptive when elicited by wind turbines.

Probabilistic characterization of wind turbine blades via aeroelasticity and spinning finite element formulation

NASA Astrophysics Data System (ADS)

Velazquez, Antonio; Swartz, R. Andrew

2012-04-01

Wind energy is an increasingly important component of this nation's renewable energy portfolio, however safe and economical wind turbine operation is a critical need to ensure continued adoption. Safe operation of wind turbine structures requires not only information regarding their condition, but their operational environment. Given the difficulty inherent in SHM processes for wind turbines (damage detection, location, and characterization), some uncertainty in conditional assessment is expected. Furthermore, given the stochastic nature of the loading on turbine structures, a probabilistic framework is appropriate to characterize their risk of failure at a given time. Such information will be invaluable to turbine controllers, allowing them to operate the structures within acceptable risk profiles. This study explores the characterization of the turbine loading and response envelopes for critical failure modes of the turbine blade structures. A framework is presented to develop an analytical estimation of the loading environment (including loading effects) based on the dynamic behavior of the blades. This is influenced by behaviors including along and across-wind aero-elastic effects, wind shear gradient, tower shadow effects, and centrifugal stiffening effects. The proposed solution includes methods that are based on modal decomposition of the blades and require frequent updates to the estimated modal properties to account for the time-varying nature of the turbine and its environment. The estimated demand statistics are compared to a code-based resistance curve to determine a probabilistic estimate of the risk of blade failure given the loading environment.

Next Generation Wind Turbine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheraghi, S. Hossein; Madden, Frank

The goal of this collaborative effort between Western New England University's College of Engineering and FloDesign Wind Turbine (FDWT) Corporation to wok on a novel areodynamic concept that could potentially lead to the next generation of wind turbines. Analytical studies and early scale model tests of FDWT's Mixer/Ejector Wind Turbine (MEWT) concept, which exploits jet-age advanced fluid dynamics, indicate that the concept has the potential to significantly reduce the cost of electricity over conventional Horizontal Axis Wind Turbines while reducing land usage. This project involved the design, fabrication, and wind tunnel testing of components of MEWT to provide the researchmore » and engineering data necessary to validate the design iterations and optimize system performance. Based on these tests, a scale model prototype called Briza was designed, fabricated, installed and tested on a portable tower to investigate and improve the design system in real world conditions. The results of these scale prototype efforts were very promising and have contributed significantly to FDWT's ongoing development of a product scale wind turbine for deployment in multiple locations around the U.S. This research was mutually beneficial to Western New England University, FDWT, and the DOE by utilizing over 30 student interns and a number of faculty in all efforts. It brought real-world wind turbine experience into the classroom to further enhance the Green Engineering Program at WNEU. It also provided on-the-job training to many students, improving their future employment opportunities, while also providing valuable information to further advance FDWT's mixer-ejector wind turbine technology, creating opportunities for future project innovation and job creation.« less

Unsteady aerodynamic analysis for offshore floating wind turbines under different wind conditions.

PubMed

Xu, B F; Wang, T G; Yuan, Y; Cao, J F

2015-02-28

A free-vortex wake (FVW) model is developed in this paper to analyse the unsteady aerodynamic performance of offshore floating wind turbines. A time-marching algorithm of third-order accuracy is applied in the FVW model. Owing to the complex floating platform motions, the blade inflow conditions and the positions of initial points of vortex filaments, which are different from the fixed wind turbine, are modified in the implemented model. A three-dimensional rotational effect model and a dynamic stall model are coupled into the FVW model to improve the aerodynamic performance prediction in the unsteady conditions. The effects of floating platform motions in the simulation model are validated by comparison between calculation and experiment for a small-scale rigid test wind turbine coupled with a floating tension leg platform (TLP). The dynamic inflow effect carried by the FVW method itself is confirmed and the results agree well with the experimental data of a pitching transient on another test turbine. Also, the flapping moment at the blade root in yaw on the same test turbine is calculated and compares well with the experimental data. Then, the aerodynamic performance is simulated in a yawed condition of steady wind and in an unyawed condition of turbulent wind, respectively, for a large-scale wind turbine coupled with the floating TLP motions, demonstrating obvious differences in rotor performance and blade loading from the fixed wind turbine. The non-dimensional magnitudes of loading changes due to the floating platform motions decrease from the blade root to the blade tip. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Unsteady aerodynamic analysis for offshore floating wind turbines under different wind conditions

PubMed Central

Xu, B. F.; Wang, T. G.; Yuan, Y.; Cao, J. F.

2015-01-01

A free-vortex wake (FVW) model is developed in this paper to analyse the unsteady aerodynamic performance of offshore floating wind turbines. A time-marching algorithm of third-order accuracy is applied in the FVW model. Owing to the complex floating platform motions, the blade inflow conditions and the positions of initial points of vortex filaments, which are different from the fixed wind turbine, are modified in the implemented model. A three-dimensional rotational effect model and a dynamic stall model are coupled into the FVW model to improve the aerodynamic performance prediction in the unsteady conditions. The effects of floating platform motions in the simulation model are validated by comparison between calculation and experiment for a small-scale rigid test wind turbine coupled with a floating tension leg platform (TLP). The dynamic inflow effect carried by the FVW method itself is confirmed and the results agree well with the experimental data of a pitching transient on another test turbine. Also, the flapping moment at the blade root in yaw on the same test turbine is calculated and compares well with the experimental data. Then, the aerodynamic performance is simulated in a yawed condition of steady wind and in an unyawed condition of turbulent wind, respectively, for a large-scale wind turbine coupled with the floating TLP motions, demonstrating obvious differences in rotor performance and blade loading from the fixed wind turbine. The non-dimensional magnitudes of loading changes due to the floating platform motions decrease from the blade root to the blade tip. PMID:25583859

Robust 1550-nm single-frequency all-fiber ns-pulsed fiber amplifier for wind-turbine predictive control by wind lidar

NASA Astrophysics Data System (ADS)

Beier, F.; de Vries, O.; Schreiber, T.; Eberhardt, R.; Tünnermann, A.; Bollig, C.; Hofmeister, P. G.; Schmidt, J.; Reuter, R.

2013-02-01

Scaling of the power yield of offshore wind farms relies on the capacity of the individual wind turbines. This results in a trend to very large rotor diameters, which are difficult to control. It is crucial to monitor the inhomogeneous wind field in front of the wind turbines at different distances to ensure reliable operation and a long lifetime at high output levels. In this contribution, we demonstrate an all-fiber ns-pulsed fiber amplifier based on cost-efficient commercially available components. The amplifier is a suitable source for coherent Doppler lidar pulses making a predictive control of the turbine operation feasible.

Method for evaluating wind turbine wake effects on wind farm performance

NASA Technical Reports Server (NTRS)

Neustadter, H. E.; Spera, D. A.

1985-01-01

A method of testing the performance of a cluster of wind turbine units an data analysis equations are presented which together form a simple and direct procedure for determining the reduction in energy output caused by the wake of an upwind turbine. This method appears to solve the problems presented by data scatter and wind variability. Test data from the three-unit Mod-2 wind turbine cluster at Goldendale, Washington, are analyzed to illustrate the application of the proposed method. In this sample case the reduction in energy was found to be about 10 percent when the Mod-2 units were separated a distance equal to seven diameters and winds were below rated.

M-X Environmental Technical Report. Environmental Characteristics of Alternative Designated Deployment Areas, Power and Energy.

DTIC Science & Technology

1980-12-22

Vertical Axis Turbine (3.4.2) A vertical axis ( Darrieus ) turbine has the following advantages over a horizontal turbine : I. Accepts wind from all...would be too large, while wind and solar could only achieve capacity factors of 40 to 50 percent. Alcohol fue’s in gas turbines would be too expensive...or biomass base load system. Wind would not be a good choice to supply such a small toad cencer, especially in Nevada/Utah, since the turbine would

WindVOiCe, a Self-Reporting Survey: Adverse Health Effects, Industrial Wind Turbines, and the Need for Vigilance Monitoring

ERIC Educational Resources Information Center

Krogh, Carmen M. E.; Gillis, Lorrie; Kouwen, Nicholas; Aramini, Jeff

2011-01-01

Industrial wind turbines have been operating in many parts of the globe. Anecdotal reports of perceived adverse health effects relating to industrial wind turbines have been published in the media and on the Internet. Based on these reports, indications were that some residents perceived they were experiencing adverse health effects. The purpose…

Systems Engineering Publications | Wind | NREL

Science.gov Websites

Different Turbine Heights. AIAA SciTech Forum: 35th Wind Energy Symposium, Grapevine, Texas, doi:10.2514 Tool for Variable-Speed Wind Turbine Generators. NREL/TP-5000-66462, doi:10.2514/6.2017-1619. Seturaman Turbine using GeneratorSE. AIAA SciTech Forum: 35th Wind Energy Symposium, Grapevine, Texas, doi:10.2172

75 FR 68821 - Endangered and Threatened Wildlife and Plants; Permit; Construction and Operation of Kaheawa II...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-09

...- megawatt (MW), 21-turbine Kaheawa Wind Power I (KWP I) project. Like KWP II, KWP I is owned by First Wind... wind turbine structures. The Hawaiian petrel and Newell's shearwater breed on Maui and feed in the open... the permit include the construction and operation of a new 21-megawatt, 14-turbine wind energy...

Modeling of the UAE Wind Turbine for Refinement of FAST{_}AD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jonkman, J. M.

The Unsteady Aerodynamics Experiment (UAE) research wind turbine was modeled both aerodynamically and structurally in the FAST{_}AD wind turbine design code, and its response to wind inflows was simulated for a sample of test cases. A study was conducted to determine why wind turbine load magnitude discrepancies-inconsistencies in aerodynamic force coefficients, rotor shaft torque, and out-of-plane bending moments at the blade root across a range of operating conditions-exist between load predictions made by FAST{_}AD and other modeling tools and measured loads taken from the actual UAE wind turbine during the NASA-Ames wind tunnel tests. The acquired experimental test data representmore » the finest, most accurate set of wind turbine aerodynamic and induced flow field data available today. A sample of the FAST{_}AD model input parameters most critical to the aerodynamics computations was also systematically perturbed to determine their effect on load and performance predictions. Attention was focused on the simpler upwind rotor configuration, zero yaw error test cases. Inconsistencies in input file parameters, such as aerodynamic performance characteristics, explain a noteworthy fraction of the load prediction discrepancies of the various modeling tools.« less

Design and initial testing of a one-bladed 30-meter-diameter rotor on the NASA/DOE mod-O wind turbine

NASA Technical Reports Server (NTRS)

Corrigan, R. D.; Ensworth, C. B. F.

1986-01-01

The concept of a one-bladed horizontal-axis wind turbine has been of interest to wind turbine designers for many years. Many designs and economic analyses of one-bladed wind turbines have been undertaken by both United States and European wind energy groups. The analyses indicate significant economic advantages but at the same time, significant dynamic response concerns. In an effort to develop a broad data base on wind turbine design and operations, the NASA Wind Energy Project Office has tested a one-bladed rotor at the NASA/DOE Mod-O Wind Turbine Facility. This is the only known test on an intermediate-sized one-bladed rotor in the United States. The 15.2-meter-radius rotor consists of a tip-controlled blade and a counterweight assembly. A rigorous test series was conducted in the Fall of 1985 to collect data on rotor performance, drive train/generator dynamics, structural dynamics, and structural loads. This report includes background information on one-bladed rotor concepts, and Mod-O one-bladed rotor test configuration, supporting design analysis, the Mod-O one-blade rotor test plan, and preliminary test results.

Structural health monitoring of wind turbine blade using fiber Bragg grating sensors and fiber optic rotary joint

NASA Astrophysics Data System (ADS)

Chen, Y.; Ni, Y. Q.; Ye, X. W.; Yang, H. X.; Zhu, S.

2012-04-01

Wind energy utilization as a reliable energy source has become a large industry in the last 20 years. Nowadays, wind turbines can generate megawatts of power and have rotor diameters that are on the order of 100 meters in diameter. One of the key components in a wind turbine is the blade which could be damaged by moisture absorption, fatigue, wind gusts or lighting strikes. The wind turbine blades should be routinely monitored to improve safety, minimize downtime, lower the risk of sudden breakdowns and associated huge maintenance and logistics costs, and provide reliable power generation. In this paper, a real-time wind turbine blade monitoring system using fiber Bragg grating (FBG) sensors with the fiber optic rotary joint (FORJ) is proposed, and applied to monitor the structural responses of a 600 W small scale wind turbine. The feasibility and effectiveness of the FORJ is validated by continuously transmitting the optical signals between the FBG interrogator at the stationary side and the FBG sensors on the rotating part. A comparison study between the measured data from the proposed system and those from an IMote2-based wireless strain measurement system is conducted.

Modelling the failure behaviour of wind turbines

NASA Astrophysics Data System (ADS)

Faulstich, S.; Berkhout, V.; Mayer, J.; Siebenlist, D.

2016-09-01

Modelling the failure behaviour of wind turbines is an essential part of offshore wind farm simulation software as it leads to optimized decision making when specifying the necessary resources for the operation and maintenance of wind farms. In order to optimize O&M strategies, a thorough understanding of a wind turbine's failure behaviour is vital and is therefore being developed at Fraunhofer IWES. Within this article, first the failure models of existing offshore O&M tools are presented to show the state of the art and strengths and weaknesses of the respective models are briefly discussed. Then a conceptual framework for modelling different failure mechanisms of wind turbines is being presented. This framework takes into account the different wind turbine subsystems and structures as well as the failure modes of a component by applying several influencing factors representing wear and break failure mechanisms. A failure function is being set up for the rotor blade as exemplary component and simulation results have been compared to a constant failure rate and to empirical wind turbine fleet data as a reference. The comparison and the breakdown of specific failure categories demonstrate the overall plausibility of the model.

Bird Mortaility at the Altamont Pass Wind Resource Area: March 1998--September 2001

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smallwood, K. S.; Thelander, C. G.

Over the past 15 years, research has shown that wind turbines in the Altamont Pass Wind Resource Area (APWRA) kill many birds, including raptors, which are protected by the Migratory Bird Treaty Act (MBTA), the Bald and Golden Eagle Protection Act, and/or state and federal Endangered Species Acts. Early research in the APWRA on avian mortality mainly attempted to identify the extent of the problem. In 1998, however, the National Renewable Energy Laboratory (NREL) initiated research to address the causal relationships between wind turbines and bird mortality. NREL funded a project by BioResource Consultants to perform this research directed atmore » identifying and addressing the causes of mortality of various bird species from wind turbines in the APWRA.With 580 megawatts (MW) of installed wind turbine generating capacity in the APWRA, wind turbines there provide up to 1 billion kilowatt-hours (kWh) of emissions-free electricity annually. By identifying and implementing new methods and technologies to reduce or resolve bird mortality in the APWRA, power producers may be able to increase wind turbine electricity production at the site and apply similar mortality-reduction methods at other sites around the state and country.« less

Finite Element Analysis for the Web Offset of Wind Turbine Blade

NASA Astrophysics Data System (ADS)

Zhou, Bo; Wang, Xin; Zheng, Changwei; Cao, Jinxiang; Zou, Pingguo

2017-05-01

The web is an important part of wind turbine blade, which improves bending properties. Much of blade process is handmade, so web offset of wind turbine blade is one of common quality defects. In this paper, a 3D parametric finite element model of a blade for 2MW turbine was established by ANSYS. Stress distributions in different web offset values were studied. There were three kinds of web offset. The systematic study of web offset was done by orthogonal experiment. The most important factor of stress distributions was found. The analysis results have certain instructive significance to design and manufacture of wind turbine blade.

The problem of the second wind turbine - a note on a common but flawed wind power estimation method

NASA Astrophysics Data System (ADS)

Gans, F.; Miller, L. M.; Kleidon, A.

2010-06-01

Several recent wind power estimates suggest how this renewable resource can meet all of the current and future global energy demand with little impact on the atmosphere. These estimates are calculated using observed wind speeds in combination with specifications of wind turbine size and density to quantify the extractable wind power. Here we show that this common methodology is flawed because it does not account for energy removal by the turbines that is necessary to ensure the conservation of energy. We will first illustrate the common but flawed methodology using parameters from a recent global quantification of wind power in a simple experimental setup. For a small number of turbines at small scales, the conservation of energy hardly results in a difference when compared to the common method. However, when applied at large to global scales, the ability of radiative gradients to generate a finite amount of kinetic energy needs to be taken into account. Using the same experimental setup, we use the simplest method to ensure the conservation of energy to show a non-negligble decrease in wind velocity after the first turbine that will successively result in lower extraction of the downwind turbines. We then show how the conservation of energy inevitably results in substantially lower estimates of wind power at the global scale. Because conservation of energy is fundamental, we conclude that ultimately environmental constraints set the upper limit for wind power availability at the larger scale rather than detailed engineering specifications of the wind turbine design and placement.

Performance and environmental impact assessment of pulse detonation based engine systems

NASA Astrophysics Data System (ADS)

Glaser, Aaron J.

Experimental research was performed to investigate the feasibility of using pulse detonation based engine systems for practical aerospace applications. In order to carry out this work a new pulse detonation combustion research facility was developed at the University of Cincinnati. This research covered two broad areas of application interest. The first area is pure PDE applications where the detonation tube is used to generate an impulsive thrust directly. The second focus area is on pulse detonation based hybrid propulsion systems. Within each of these areas various studies were performed to quantify engine performance. Comparisons of the performance between detonation and conventional deflagration based engine cycles were made. Fundamental studies investigating detonation physics and flow dynamics were performed in order to gain physical insight into the observed performance trends. Experimental studies were performed on PDE-driven straight and diverging ejectors to determine the system performance. Ejector performance was quantified by thrust measurements made using a damped thrust stand. The effects of PDE operating parameters and ejector geometric parameters on thrust augmentation were investigated. For all cases tested, the maximum thrust augmentation is found to occur at a downstream ejector placement. The optimum ejector geometry was determined to have an overall length of LEJECT/DEJECT =5.61, including an intermediate-straight section length of LSTRT /DEJECT=2, and diverging exhaust section with 4 deg half-angle. A maximum thrust augmentation of 105% was observed while employing the optimized ejector geometry and operating the PDE at a fill-fraction of 0.6 and a frequency of 10 Hz. When operated at a fill-fraction of 1.0 and a frequency of 30 Hz, the thrust augmentation of the optimized PDE-driven ejector system was observed to be 71%. Static pressure was measured along the interior surface of the ejector, including the inlet and exhaust sections. The diverging ejector pressure distribution shows that the diverging section acts as a subsonic diffuser. To provide a better explanation of the observed performance trends, shadowgraph images of the detonation wave and starting vortex interacting with the ejector inlet were obtained. The acoustic signature of a pulse detonation engine was characterized in both the near-field and far-field regimes. Experimental measurements were performed in an anechoic test facility designed for jet noise testing. Both shock strength and speed were mapped as a function of radial distance and direction from the PDE exhaust plane. It was found that the PDE generated pressure field can be reasonably modeled by a theoretical point-source explosion. The effect of several exit nozzle configurations on the PDE acoustic signature was studies. These included various chevron nozzles, a perforated nozzle, and a set of proprietary noise attenuation mufflers. Experimental studies were carried out to investigate the performance of a hybrid propulsion system integrating an axial flow turbine with multiple pulse detonation combustors. The integrated system consisted of a circular array of six pulse detonation combustor (PDC) tubes exhausting through an axial flow turbine. Turbine component performance was quantified by measuring the amount of power generated by the turbine section. Direct comparisons of specific power output and turbine efficiency between a PDC-driven turbine and a turbine driven by steady-flow combustors were made. It was found that the PDC-driven turbine had comparable performance to that of a steady-burner-driven turbine across the operating map of the turbine.

A Hybrid Wind-Farm Parametrization for Mesoscale and Climate Models

NASA Astrophysics Data System (ADS)

Pan, Yang; Archer, Cristina L.

2018-04-01

To better understand the potential impact of wind farms on weather and climate at the regional to global scales, a new hybrid wind-farm parametrization is proposed for mesoscale and climate models. The proposed parametrization is a hybrid model because it is not based on physical processes or conservation laws, but on the multiple linear regression of the results of large-eddy simulations (LES) with the geometric properties of the wind-farm layout (e.g., the blockage ratio and blockage distance). The innovative aspect is that each wind turbine is treated individually based on its position in the farm and on the wind direction by predicting the velocity upstream of each turbine. The turbine-induced forces and added turbulence kinetic energy (TKE) are first derived analytically and then implemented in the Weather Research and Forecasting model. Idealized simulations of the offshore Lillgrund wind farm are conducted. The wind-speed deficit and TKE predicted with the hybrid model are in excellent agreement with those from the LES results, while the wind-power production estimated with the hybrid model is within 10% of that observed. Three additional wind farms with larger inter-turbine spacing than at Lillgrund are also considered, and a similar agreement with LES results is found, proving that the hybrid parametrization works well with any wind farm regardless of the spacing between turbines. These results indicate the wind-turbine position, wind direction, and added TKE are essential in accounting for the wind-farm effects on the surroundings, for which the hybrid wind-farm parametrization is a promising tool.

Improving Energy Security for Air Force Installations

DTIC Science & Technology

2015-09-01

Wind power is a mature technology, with wind turbines first being used for electricity in the late 19th century. The Air Force operates two wind ...company, and the military unit receives energy credits back on its bill. Two concepts are important when considering the turbine size for a wind ...generation and consumption must remain balanced for a grid, so wind turbines are rarely used as a sole energy source since power is only generated

Yawing characteristics during slippage of the nacelle of a multi MW wind turbine

NASA Astrophysics Data System (ADS)

Kim, M.-G.; Dalhoff, P. H.; Gust, P.

2016-09-01

High aerodynamic yaw loads coupled with electrical failures in the wind turbine can result to a slippage of the nacelle, due to limited braking capabilities of the yaw system. A slippage on the other hand can lead to a mechanical malfunction of the yaw system. To analyse the yawing characteristics of a wind turbine during nacelle slippage situations, a detailed multibody system model of the yaw system has been developed and incorporated in a multibody system model of a wind turbine based on a 3.3 MW turbine. Extreme load cases which lead to a nacelle slippage have been simulated. The dynamics and loads on different wind turbine components are presented and discussed. First results show minimal load increases of the rotor torque and the bending moments of the blade root sections during slippage but unfavourable rotational speeds of the yaw drives.

Lifting system and apparatus for constructing wind turbine towers

DOEpatents

Livingston, Tracy; Schrader, Terry; Goldhardt, James; Lott, James

2011-02-01

The disclosed invention is utilized for mounting a wind turbine and blade assembly on the upper end of a wind turbine tower. The invention generally includes a frame or truss that is pivotally secured to the top bay assembly of the tower. A transverse beam is connected to the frame or truss and extends fore of the tower when the frame or truss is in a first position and generally above the tower when in a second position. When in the first position, a wind turbine or blade assembly can be hoisted to the top of the tower. The wind turbine or blade assembly is then moved into position for mounting to the tower as the frame or truss is pivoted to a second position. When the turbine and blade assembly are secured to the tower, the frame or truss is disconnected from the tower and lowered to the ground.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huskey, A.; Bowen, A.; Jager, D.

This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers to wind energy expansion by providing independent testing results for small wind turbines (SWT). In total, five turbines were tested at the National Wind Technology Center (NWTC) as a part of this project. Safety and function testing is one of up to five tests performed on the turbines, including power performance, duration, noise, and power-quality tests. NWTC testing results provide manufacturers with reports that may be used to meet part of small wind turbine certificationmore » requirements. The test equipment includes a Mariah Windspire wind turbine mounted on a monopole tower. L&E Machine manufactured the turbine in the United States. The inverter was manufactured separately by Technology Driven Products in the United States. The system was installed by the NWTC site operations group with guidance and assistance from Mariah Power.« less

Influences of Atmospheric Stability State on Wind Turbine Aerodynamic Loadings

NASA Astrophysics Data System (ADS)

Vijayakumar, Ganesh; Lavely, Adam; Brasseur, James; Paterson, Eric; Kinzel, Michael

2011-11-01

Wind turbine power and loadings are influenced by the structure of atmospheric turbulence and thus on the stability state of the atmosphere. Statistical differences in loadings with atmospheric stability could impact controls, blade design, etc. Large-eddy simulation (LES) of the neutral and moderately convective atmospheric boundary layer (NBL, MCBL) are used as inflow to the NREL FAST advanced blade-element momentum theory code to predict wind turbine rotor power, sectional lift and drag, blade bending moments and shaft torque. Using horizontal homogeneity, we combine time and ensemble averages to obtain converged statistics equivalent to ``infinite'' time averages over a single turbine. The MCBL required longer effective time periods to obtain converged statistics than the NBL. Variances and correlation coefficients among wind velocities, turbine power and blade loadings were higher in the MCBL than the NBL. We conclude that the stability state of the ABL strongly influences wind turbine performance. Supported by NSF and DOE.

Hub vortex instability within wind turbine wakes: Effects of wind turbulence, loading conditions, and blade aerodynamics

NASA Astrophysics Data System (ADS)

Ashton, Ryan; Viola, Francesco; Camarri, Simone; Gallaire, Francois; Iungo, Giacomo Valerio

2016-11-01

The near wake of wind turbines is characterized by the presence of the hub vortex, which is a coherent vorticity structure generated from the interaction between the root vortices and the boundary layer evolving over the turbine nacelle. By moving downstream, the hub vortex undergoes an instability with growth rate, azimuthal and axial wavenumbers determined by the characteristics of the incoming wind and turbine aerodynamics. Thus, a large variability of the hub vortex instability is expected for wind energy applications with consequent effects on wake downstream evolution, wake interactions within a wind farm, power production, and fatigue loads on turbines invested by wakes generated upstream. In order to predict characteristics of the hub vortex instability for different operating conditions, linear stability analysis is carried out by considering different statistics of the incoming wind turbulence, thrust coefficient, tip speed ratio, and blade lift distribution of a wind turbine. Axial and azimuthal wake velocity fields are modeled through Carton-McWilliams velocity profiles by mimicking the presence of the hub vortex, helicoidal tip vortices, and matching the wind turbine thrust coefficient predicted through the actuator disk model. The linear stability analysis shows that hub vortex instability is strongly affected by the wind turbine loading conditions, and specifically it is promoted by a larger thrust coefficient. A higher load of the wind turbines produces an enhanced axial velocity deficit and, in turn, higher shear in the radial direction of the streamwise velocity. The axial velocity shear within the turbine wake is also the main physical mechanism promoting the hub vortex instability when varying the lift distribution over the blade span for a specific loading condition. Cases with a larger velocity deficit in proximity of the wake center and less aerodynamic load towards the blade tip result to be more unstable. Moreover, wake swirl promotes hub vortex instability, and it can also affect the azimuthal wave number of the most unstable mode. Finally, higher Reynolds stresses and turbulent eddy viscosity decrease both growth rate and azimuthal wave number of the most unstable mode.

High-Order Numerical Simulations of Wind Turbine Wakes

NASA Astrophysics Data System (ADS)

Kleusberg, E.; Mikkelsen, R. F.; Schlatter, P.; Ivanell, S.; Henningson, D. S.

2017-05-01

Previous attempts to describe the structure of wind turbine wakes and their mutual interaction were mostly limited to large-eddy and Reynolds-averaged Navier-Stokes simulations using finite-volume solvers. We employ the higher-order spectral-element code Nek5000 to study the influence of numerical aspects on the prediction of the wind turbine wake structure and the wake interaction between two turbines. The spectral-element method enables an accurate representation of the vortical structures, with lower numerical dissipation than the more commonly used finite-volume codes. The wind-turbine blades are modeled as body forces using the actuator-line method (ACL) in the incompressible Navier-Stokes equations. Both tower and nacelle are represented with appropriate body forces. An inflow boundary condition is used which emulates homogeneous isotropic turbulence of wind-tunnel flows. We validate the implementation with results from experimental campaigns undertaken at the Norwegian University of Science and Technology (NTNU Blind Tests), investigate parametric influences and compare computational aspects with existing numerical simulations. In general the results show good agreement between the experiments and the numerical simulations both for a single-turbine setup as well as a two-turbine setup where the turbines are offset in the spanwise direction. A shift in the wake center caused by the tower wake is detected similar to experiments. The additional velocity deficit caused by the tower agrees well with the experimental data. The wake is captured well by Nek5000 in comparison with experiments both for the single wind turbine and in the two-turbine setup. The blade loading however shows large discrepancies for the high-turbulence, two-turbine case. While the experiments predicted higher thrust for the downstream turbine than for the upstream turbine, the opposite case was observed in Nek5000.

The Electromagnetic Impact of Wind Turbines

DTIC Science & Technology

2015-07-06

Applied Project 4. TITLE AND SUBTITLE THE ELECTROMAGNETIC IMPACT OF WIND TURBINES 5. FUNDING NUMBERS 6. AUTHOR(S) Gregory Sasarita and Charles R...DISTRIBUTION CODE A 13. ABSTRACT (maximum 200 words) The objective of this project was to investigate the impact that a wind turbine can have on

75 FR 44067 - Conservation Reserve Program

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-28

... land, and installation of wind turbines. Therefore, Sec. 1410.63 is amended to implement the specific... emergencies, but was not specified as a permitted use in the CFR. Wind turbine installation provisions are... requires a payment reduction for the permissive use for wind turbine installation. All of the permissive...

Characterization of wind velocities in the wake of a full scale wind turbine using three ground-based synchronized WindScanners

NASA Astrophysics Data System (ADS)

Yazicioglu, Hasan; Angelou, Nikolas; Mikkelsen, Torben; José Trujillo, Juan

2016-09-01

The wind energy community is in need of detailed full-field measurements in the wake of wind turbines. Here, three dimensional(3D) wind vector field measurements obtained in the near-wake region behind a full-scale test turbine are presented. Specifically, the wake of a NEG Nordtank turbine, installed at Risoe test field, has been measured from 0 to 2 diameters downstream. For this, three ground-based synchronised short-range WindScanners and a spinner lidar have been used. The 3D wind velocity field has been reconstructed in horizontal and vertical planes crossing the hub. The 10-min mean values of the three wind components reveal detailed information regarding the wake properties while propagating downwind over flat terrain. Furthermore, the wake centre is tracked from the measurements and its meander is investigated as function of yaw misalignment of the turbine. The centre-line wake deficit is calculated both in a Nacelle and Moving Frame of Reference. The results can be used in quantitative validation of numerical wake models.

Impacts of a large array of offshore wind farms on precipitation during hurricane Harvey

NASA Astrophysics Data System (ADS)

Pan, Y.; Archer, C. L.

2017-12-01

Hurricane Harvey brought to the Texas coast possibly the heaviest rain ever recorded in U.S. history, which then caused flooding at unprecedented levels. Previous studies have shown that large arrays of offshore wind farms can extract kinetic energy from a hurricane and thus reduce the wind and storm surge. This study will quantitatively test weather the offshore turbines may also affect precipitation patterns. The Weather Research Forecast model is employed to model Harvey and the offshore wind farms are parameterized as elevated drag and turbulence kinetic energy sources. The turbines (7.8 MW Enercon-126 with rotor diameter D=127 m) are placed along the coast of Texas and Louisiana within 100 km from the shore, where the water depth is below 200 meters. Three spacing between turbines are considered (with the number of turbines in parenthesis): 7D×7D (149,936), 9D×9D (84,339), and 11D×11D (56,226). A fourth case (9D×9D) with a smaller area and thus less turbines (33,363) is added to the simulations to emphasize the impacts of offshore turbines installed specifically to protect the city of Houston, which was flooded heavily during hurricane Harvey. The model is integrated for 24 hours from 00UTC Aug 26th, 2017 to 00UTC Aug 27th, 2017. Model results indicate that the offshore wind farms have a strong impact on the distribution of 24-hour accumulated precipitation, with an obvious decrease onshore, downstream of the wind farms, and an increase in the offshore areas, upstream of or within the wind farms. A sector covering the metro-Houston area is chosen to study the sensitivity of the four different wind farm layouts. The spatial-average 24-hour accumulated precipitation is decreased by 37%, 28%, 20% and 25% respectively for the four cases. Compared with the control case with no wind turbines, increased horizontal wind divergence and lower vertical velocity are found where the precipitation is reduced onshore, whereas increased horizontal wind convergence and higher vertical velocity occur upstream or within the offshore wind farms. These preliminary results suggest that large arrays of offshore wind turbines can effectively protect the coast from heavy rain during hurricanes and that smart layouts with fewer turbines over smaller areas can be almost as effective as those with more turbines over larger areas.

RANS simulations of wind turbine wakes: optimal tuning of turbulence closure and aerodynamic loads from LiDAR and SCADA data

NASA Astrophysics Data System (ADS)

Letizia, Stefano; Puccioni, Matteo; Zhan, Lu; Viola, Francesco; Camarri, Simone; Iungo, Giacomo Valerio

2017-11-01

Numerical simulations of wakes produced by utility-scale wind turbines still present challenges related to the variability of the atmospheric conditions and, in the most of the cases, the lack of information about the geometry and aerodynamic performance of the wind turbine blades. In order to overcome the mentioned difficulties, we propose a RANS solver for which turbine aerodynamic forcing and turbulence closure are calibrated through LiDAR and SCADA data acquired for an onshore wind farm. The wind farm under examination is located in North Texas over a relatively flat terrain. The experimental data are leveraged to maximize accuracy of the RANS predictions in terms of wake velocity field and power capture for different atmospheric stability conditions and settings of the wind turbines. The optimization of the RANS parameters is performed through an adjoint-RANS formulation and a gradient-based procedure. The optimally-tuned aerodynamic forcing and turbulence closure are then analyzed in order to investigate effects of the atmospheric stability on the evolution of wind turbine wakes and power performance. The proposed RANS solver has low computational costs comparable to those of wake engineering models, which make it a compelling tool for wind farm control and optimization. Acknowledgments: NSF I/UCRC WindSTAR IIP 1362033 and TACC.

A parabolic velocity-decomposition method for wind turbines

NASA Astrophysics Data System (ADS)

Mittal, Anshul; Briley, W. Roger; Sreenivas, Kidambi; Taylor, Lafayette K.

2017-02-01

An economical parabolized Navier-Stokes approximation for steady incompressible flow is combined with a compatible wind turbine model to simulate wind turbine flows, both upstream of the turbine and in downstream wake regions. The inviscid parabolizing approximation is based on a Helmholtz decomposition of the secondary velocity vector and physical order-of-magnitude estimates, rather than an axial pressure gradient approximation. The wind turbine is modeled by distributed source-term forces incorporating time-averaged aerodynamic forces generated by a blade-element momentum turbine model. A solution algorithm is given whose dependent variables are streamwise velocity, streamwise vorticity, and pressure, with secondary velocity determined by two-dimensional scalar and vector potentials. In addition to laminar and turbulent boundary-layer test cases, solutions for a streamwise vortex-convection test problem are assessed by mesh refinement and comparison with Navier-Stokes solutions using the same grid. Computed results for a single turbine and a three-turbine array are presented using the NREL offshore 5-MW baseline wind turbine. These are also compared with an unsteady Reynolds-averaged Navier-Stokes solution computed with full rotor resolution. On balance, the agreement in turbine wake predictions for these test cases is very encouraging given the substantial differences in physical modeling fidelity and computer resources required.

Wind speed reductions by large-scale wind turbine deployments lower turbine efficiencies and set low generation limits.

PubMed

Miller, Lee M; Kleidon, Axel

2016-11-29

Wind turbines generate electricity by removing kinetic energy from the atmosphere. Large numbers of wind turbines are likely to reduce wind speeds, which lowers estimates of electricity generation from what would be presumed from unaffected conditions. Here, we test how well wind power limits that account for this effect can be estimated without explicitly simulating atmospheric dynamics. We first use simulations with an atmospheric general circulation model (GCM) that explicitly simulates the effects of wind turbines to derive wind power limits (GCM estimate), and compare them to a simple approach derived from the climatological conditions without turbines [vertical kinetic energy (VKE) estimate]. On land, we find strong agreement between the VKE and GCM estimates with respect to electricity generation rates (0.32 and 0.37 W e m -2 ) and wind speed reductions by 42 and 44%. Over ocean, the GCM estimate is about twice the VKE estimate (0.59 and 0.29 W e m -2 ) and yet with comparable wind speed reductions (50 and 42%). We then show that this bias can be corrected by modifying the downward momentum flux to the surface. Thus, large-scale limits to wind power use can be derived from climatological conditions without explicitly simulating atmospheric dynamics. Consistent with the GCM simulations, the approach estimates that only comparatively few land areas are suitable to generate more than 1 W e m -2 of electricity and that larger deployment scales are likely to reduce the expected electricity generation rate of each turbine. We conclude that these atmospheric effects are relevant for planning the future expansion of wind power.

Wind speed reductions by large-scale wind turbine deployments lower turbine efficiencies and set low generation limits

PubMed Central

Miller, Lee M.; Kleidon, Axel

2016-01-01

Wind turbines generate electricity by removing kinetic energy from the atmosphere. Large numbers of wind turbines are likely to reduce wind speeds, which lowers estimates of electricity generation from what would be presumed from unaffected conditions. Here, we test how well wind power limits that account for this effect can be estimated without explicitly simulating atmospheric dynamics. We first use simulations with an atmospheric general circulation model (GCM) that explicitly simulates the effects of wind turbines to derive wind power limits (GCM estimate), and compare them to a simple approach derived from the climatological conditions without turbines [vertical kinetic energy (VKE) estimate]. On land, we find strong agreement between the VKE and GCM estimates with respect to electricity generation rates (0.32 and 0.37 We m−2) and wind speed reductions by 42 and 44%. Over ocean, the GCM estimate is about twice the VKE estimate (0.59 and 0.29 We m−2) and yet with comparable wind speed reductions (50 and 42%). We then show that this bias can be corrected by modifying the downward momentum flux to the surface. Thus, large-scale limits to wind power use can be derived from climatological conditions without explicitly simulating atmospheric dynamics. Consistent with the GCM simulations, the approach estimates that only comparatively few land areas are suitable to generate more than 1 We m−2 of electricity and that larger deployment scales are likely to reduce the expected electricity generation rate of each turbine. We conclude that these atmospheric effects are relevant for planning the future expansion of wind power. PMID:27849587

Sea Surface Wakes Observed by Spaceborne SAR in the Offshore Wind Farms

NASA Astrophysics Data System (ADS)

Li, Xiaoming; Lehner, Susanne; Jacobsen, Sven

2014-11-01

In the paper, we present some X-band spaceborne synthetic aperture radar (SAR) TerraSAR-X (TS-X) images acquired at the offshore wind farms in the North Sea and the East China Sea. The high spatial resolution SAR images show different sea surface wake patterns downstream of the offshore wind turbines. The analysis suggests that there are major two types of wakes among the observed cases. The wind turbine wakes generated by movement of wind around wind turbines are the most often observed cases. In contrast, due to the strong local tidal currents in the near shore wind farm sites, the tidal current wakes induced by tidal current impinging on the wind turbine piles are also observed in the high spatial resolution TS-X images. The discrimination of the two types of wakes observed in the offshore wind farms is also described in the paper.

Examples of the Influence of Turbine Wakes on Downwind Power Output, Surface Wind Speed, Turbulence and Flow Convergence in Large Wind Farms

NASA Astrophysics Data System (ADS)

Takle, E. S.; Rajewski, D. A.; Lundquist, J. K.; Doorenbos, R. K.

2014-12-01

We have analyzed turbine power and concurrent wind speed, direction and turbulence data from surface 10-m flux towers in a large wind farm for experiments during four summer periods as part of the Crop Wind Energy Experiment (CWEX). We use these data to analyze surface differences for a near-wake (within 2.5 D of the turbine line), far wake (17 D downwind of the turbine line), and double wake (impacted by two lines of turbines about 34 D downwind of the first turbine line) locations. Composites are categorized by10 degree directional intervals and three ambient stability categories as defined by Rajewski et al. (2013): neutral (|z/L|<0.05), stable (z/L>0.05) and unstable (z/L<-0.05), where z is the height of the measurement and L is the Monin-Obhukov length. The dominant influence of the turbines is under stably stratified conditions (i. e., mostly at night). A 25% to 40% increase in mean wind speed occurs when turbine wakes are moving over the downwind station at a distance of 2.8 D and 5.4 D (D = fan diameter). For the double wake condition (flux station leeward of two lines of turbines) we find a daytime (unstable conditions) speed reduction of 20% for southerly wind, but for nighttime (stable conditions) the surface speeds are enhancedby 40-60% for SSW-SW winds. The speedup is reduced as wind directions shift to the west. We interpret these speed variations as due to the rotation of the wake and interaction (or not) with higher speed air above the rotor layer in highly sheared nocturnal low-level jet conditions. From a cluster of flux stations and three profiling lidars deployed within and around a cluster of turbines in 2013 (CWEX-13) we found evidence of mesoscale influences. In particular, surface convergence (wind direction deflection of 10-20 degrees) was observed during periods of low nighttime winds (hub-height winds of 4-6 m/s) with power reduction of 50-75%. This is consistent with a similar range of deflection observed from a line of turbines in CWEX-11, In the mid to late afternoon hours when hub-height wind speeds are between 5-10 m/s convergence periods have been observed, with power enhancements of 20-40% at several locations around the farm.

Dedication of the Mod-0 Wind Turbine at Plum Brook Station

NASA Image and Video Library

1975-10-21

Energy Research and Development Administration (ERDA) Administrator Robert Seamans addresses the crowd at the dedication ceremony for the Mod-0 100-kilowatt wind turbine at the National Aeronautics and Space Administration’s (NASA) Plum Brook Station. The wind turbine program was a joint NASA/ERDA effort to develop less expensive forms of energy during the 1970s. NASA Lewis was able to use its experience with aerodynamics, powerplants, and energy transfer to develop efficient and cost-effective wind energy systems. The Plum Brook wind turbine was the first of a series of increasingly powerful NASA-ERDA wind turbines built around the nation. From left to right: Congressional Committee aide John Dugan, retired S. Morgan Smith Company chief engineer Carl Wilcox, windmill pioneer Beauchamp Smith, NASA Administrator James Fletcher, Seamans, and Lewis Center Director Bruce Lundin. The three men to the right are unidentified.

Aerodynamic study of a small wind turbine with emphasis on laminar and transition flows

NASA Astrophysics Data System (ADS)

Niculescu, M. L.; Cojocaru, M. G.; Crunteanu, D. E.

2016-06-01

The wind energy is huge but unfortunately, wind turbines capture only a little part of this enormous green energy. Furthermore, it is impossible to put multi megawatt wind turbines in the cities because they generate a lot of noise and discomfort. Instead, it is possible to install small Darrieus and horizontal-axis wind turbines with low tip speed ratios in order to mitigate the noise as much as possible. Unfortunately, the flow around this wind turbine is quite complex because the run at low Reynolds numbers. Therefore, this flow is usually a mixture of laminar, transition and laminar regimes with bubble laminar separation that is very difficult to simulate from the numerical point of view. Usually, transition and laminar regimes with bubble laminar separation are ignored. For this reason, this paper deals with laminar and transition flows in order to provide some brightness in this field.

Tour A (Wind) Turbine - #RoundIsAShape (U.S. Department of Energy) GoPro

ScienceCinema

Edelman, Simon

2018-06-12

Get an exclusive and entertaining look inside of a wind turbine. Simon and Andy strap GoPro's to their heads and guide you as they travel 270 feet up to the top of a turbine at the National Wind Technology Center in Golden, CO.

Multi-piece wind turbine rotor blades and wind turbines incorporating same

DOEpatents

Moroz,; Mieczyslaw, Emilian [San Diego, CA

2008-06-03

A multisection blade for a wind turbine includes a hub extender having a pitch bearing at one end, a skirt or fairing having a hole therethrough and configured to mount over the hub extender, and an outboard section configured to couple to the pitch bearing.

75 FR 74042 - Intent To Prepare an Environmental Impact Statement and To Conduct Scoping Meetings...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-30

... proposed Project would consist of up to 100 wind turbine generators with a combined total generating... its wind generation turbines and related facilities. Available overview information indicates this... process for the wind turbine strings and associated facilities considered sensitive resources, and the...

Wind Turbines Make Waves: Why Some Residents near Wind Turbines Become Ill

ERIC Educational Resources Information Center

Havas, Magda; Colling, David

2011-01-01

People who live near wind turbines complain of symptoms that include some combination of the following: difficulty sleeping, fatigue, depression, irritability, aggressiveness, cognitive dysfunction, chest pain/pressure, headaches, joint pain, skin irritations, nausea, dizziness, tinnitus, and stress. These symptoms have been attributed to the…

Forced pitch motion of wind turbines

NASA Astrophysics Data System (ADS)

Leble, V.; Barakos, G.

2016-09-01

The possibility of a wind turbine entering vortex ring state during pitching oscillations is explored in this paper. The aerodynamic performance of the rotor was computed using the Helicopter Multi-Block flow solver. This code solves the Navier-Stokes equations in integral form using the arbitrary Lagrangian-Eulerian formulation for time-dependent domains with moving boundaries. A 10-MW wind turbine was put to perform yawing and pitching oscillations suggesting the partial vortex ring state during pitching motion. The results also show the strong effect of the frequency and amplitude of oscillations on the wind turbine performance.

International Symposium on Wind Energy Systems, Held at Cambridge University, on 7-9 September 1976

DTIC Science & Technology

1976-12-07

Darrieus turbine design. B.F. Blackwell, Sandia Laboratories, USA. Some design aspects of high-speed vertical- axis wind turbines . R.J. Templin and P...Energy, Energy Conversion, Power Systems, Windmills, Wind Turbines . 20. §6PAT(Cin~hW. "" aid. it 00e096 suf id""App hr 6Řb nwe) This report of qs brief...large wind turbines ocerating in lare arrays, and the output (with and without storage) of several such arrwef awhen geographically dispersed, has yet to

A local-circulation model for Darrieus vertical-axis wind turbines

NASA Astrophysics Data System (ADS)

Masse, B.

1986-04-01

A new computational model for the aerodynamics of the vertical-axis wind turbine is presented. Based on the local-circulation method generalized for curved blades, combined with a wake model for the vertical-axis wind turbine, it differs markedly from current models based on variations in the streamtube momentum and vortex models using the lifting-line theory. A computer code has been developed to calculate the loads and performance of the Darrieus vertical-axis wind turbine. The results show good agreement with experimental data and compare well with other methods.

Design and operating experience on the US Department of Energy experimental Mod-0 100-kW wind turbine

NASA Technical Reports Server (NTRS)

Glasgow, J. C.; Birchenough, A. G.

1978-01-01

The experimental wind turbine was designed and fabricated to assess technology requirements and engineering problems of large wind turbines. The machine has demonstrated successful operation in all of its design modes and served as a prototype developmental test bed for the Mod-0A operational wind turbines which are currently used on utility networks. The mechanical and control system are described as they evolved in operational tests and some of the experience with various systems in the downwind rotor configurations are elaborated.

Efficiency of the DOMUS 750 vertical-axis wind turbine

NASA Astrophysics Data System (ADS)

Hallock, Kyle; Rasch, Tyler; Ju, Guoqiang; Alonso-Marroquin, Fernando

2017-06-01

The aim of this paper is to present some preliminary results on the efficiency of a wind turbine for an off-grid housing unit. To generate power, the unit uses a photovoltaic solar array and a vertical-axis wind turbine (VAWT). The existing VAWT was analysed to improve efficiency and increase power generation. There were found to be two main sources of inefficiency: 1. the 750W DC epicyclic generator performed poorly in low winds, and 2. the turbine blades wobbled, allowing for energy loss due to off-axis rotation. A 12V DC permanent magnet alternator was chosen that met the power requirements of the housing unit and would generate power at lower wind speeds. A support bracket was designed to prevent the turbine blades from wobbling.

On the wake of a Darrieus turbine

NASA Technical Reports Server (NTRS)

Base, T. E.; Phillips, P.; Robertson, G.; Nowak, E. S.

1981-01-01

The theory and experimental measurements on the aerodynamic decay of a wake from high performance vertical axis wind turbine are discussed. In the initial experimental study, the wake downstream of a model Darrieus rotor, 28 cm diameter and a height of 45.5 cm, was measured in a Boundary Layer Wind Tunnel. The wind turbine was run at the design tip speed ratio of 5.5. It was found that the wake decayed at a slower rate with distance downstream of the turbine, than a wake from a screen with similar troposkein shape and drag force characteristics as the Darrieus rotor. The initial wind tunnel results indicated that the vertical axis wind turbines should be spaced at least forty diameters apart to avoid mutual power depreciation greater than ten per cent.

Installation and checkout of the DOE/NASA Mod-1 2000-kW wind turbine generator

NASA Technical Reports Server (NTRS)

Puthoff, R. L.; Collins, J. L.; Wolf, R. A.

1980-01-01

The paper describes the DOE/NASA Mod-1 wind turbine generator, its assembly and testing, and its installation at Boone, North Carolina. The paper concludes with performance data taken during the initial tests conducted on the machine. The successful installation and initial operation of the Mod-1 wind turbine generator has had the following results: (1) megawatt-size wind turbines can be operated satisfactorily on utility grids; (2) the structural loads can be predicted by existing codes; (3) assembly of the machine on top of the tower presents no major problem; (4) large blades 100 ft long can be transported long distances and over mountain roads; and (5) operating experience and performance data will contribute substantially to the design of future low-cost wind turbines.

WIND TURBINES CAUSE CHRONIC STRESS IN BADGERS (MELES MELES) IN GREAT BRITAIN.

PubMed

Agnew, Roseanna C N; Smith, Valerie J; Fowkes, Robert C

2016-07-01

A paucity of data exists with which to assess the effects of wind turbines noise on terrestrial wildlife, despite growing concern about the impact of infrasound from wind farms on human health and well-being. In 2013, we assessed whether the presence of turbines in Great Britain impacted the stress levels of badgers ( Meles meles ) in nearby setts. Hair cortisol levels were used to determine if the badgers were physiologically stressed. Hair of badgers living <1 km from a wind farm had a 264% higher cortisol level than badgers >10 km from a wind farm. This demonstrates that affected badgers suffer from enhanced hypothalamo-pituitary-adrenal activity and are physiologically stressed. No differences were found between the cortisol levels of badgers living near wind farms operational since 2009 and 2012, indicating that the animals do not become habituated to turbine disturbance. Cortisol levels in the affected badgers did not vary in relation to the distance from turbines within 1 km, wind farm annual power output, or number of turbines. We suggest that the higher cortisol levels in affected badgers is caused by the turbines' sound and that these high levels may affect badgers' immune systems, which could result in increased risk of infection and disease in the badger population.

Towards reduced order modelling for predicting the dynamics of coherent vorticity structures within wind turbine wakes.

PubMed

Debnath, M; Santoni, C; Leonardi, S; Iungo, G V

2017-04-13

The dynamics of the velocity field resulting from the interaction between the atmospheric boundary layer and a wind turbine array can affect significantly the performance of a wind power plant and the durability of wind turbines. In this work, dynamics in wind turbine wakes and instabilities of helicoidal tip vortices are detected and characterized through modal decomposition techniques. The dataset under examination consists of snapshots of the velocity field obtained from large-eddy simulations (LES) of an isolated wind turbine, for which aerodynamic forcing exerted by the turbine blades on the atmospheric boundary layer is mimicked through the actuator line model. Particular attention is paid to the interaction between the downstream evolution of the helicoidal tip vortices and the alternate vortex shedding from the turbine tower. The LES dataset is interrogated through different modal decomposition techniques, such as proper orthogonal decomposition and dynamic mode decomposition. The dominant wake dynamics are selected for the formulation of a reduced order model, which consists in a linear time-marching algorithm where temporal evolution of flow dynamics is obtained from the previous temporal realization multiplied by a time-invariant operator.This article is part of the themed issue 'Wind energy in complex terrains'. © 2017 The Author(s).