Science.gov

Sample records for wind turbine transformers

  1. Wind Turbine

    USGS Multimedia Gallery

    The species of bats that are most susceptible to wind turbines all roost in trees throughout the year, leading some scientists to speculate that they may be visually mistaking wind turbines for trees in which to roost....

  2. Direct drive wind turbine

    DOEpatents

    Bywaters, Garrett; Danforth, William; Bevington, Christopher; Jesse, Stowell; Costin, Daniel

    2006-10-10

    A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

  3. Direct drive wind turbine

    DOEpatents

    Bywaters, Garrett; Danforth, William; Bevington, Christopher; Stowell, Jesse; Costin, Daniel

    2006-07-11

    A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

  4. Direct drive wind turbine

    DOEpatents

    Bywaters, Garrett Lee; Danforth, William; Bevington, Christopher; Stowell, Jesse; Costin, Daniel

    2006-09-19

    A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

  5. Direct drive wind turbine

    DOEpatents

    Bywaters, Garrett; Danforth, William; Bevington, Christopher; Jesse, Stowell; Costin, Daniel

    2007-02-27

    A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

  6. User's Guide to MBC3: Multi-Blade Coordinate Transformation Code for 3-Bladed Wind Turbine

    SciTech Connect

    Bir, G. S.

    2010-09-01

    This guide explains how to use MBC3, a MATLAB-based script NREL developed to perform multi-blade coordinate transformation of system matrices for three-bladed wind turbines. In its current form, MBC3 can be applied to system matrices generated by FAST.2.

  7. Wind turbine

    DOEpatents

    Cheney, Jr., Marvin C. (Glastonbury, CT)

    1982-01-01

    A wind turbine of the type having an airfoil blade (15) mounted on a flexible beam (20) and a pitch governor (55) which selectively, torsionally twists the flexible beam in response to wind turbine speed thereby setting blade pitch, is provided with a limiter (85) which restricts unwanted pitch change at operating speeds due to torsional creep of the flexible beam. The limiter allows twisting of the beam by the governor under excessive wind velocity conditions to orient the blades in stall pitch positions, thereby preventing overspeed operation of the turbine. In the preferred embodiment, the pitch governor comprises a pendulum (65,70) which responds to changing rotor speed by pivotal movement, the limiter comprising a resilient member (90) which engages an end of the pendulum to restrict further movement thereof, and in turn restrict beam creep and unwanted blade pitch misadjustment.

  8. Wind turbine

    SciTech Connect

    Traudt, R.F.

    1986-12-30

    This patent describes a wind turbine device having a main rotatable driven shaft, elongated blades operatively mounted on the main shaft for unitary rotation with the main shaft. The blade extends substantially radially away from the main shaft and is adapted to fold downwind under naturally occurring forces and simultaneously feather in direct response to the folding movement. A means associated with the blades is included for increasing the rate of fold relative to the rate of feather as the speed of rotation increases.

  9. A medium frequency transformer with multiple secondary windings for medium voltage converter based wind turbine power generating systems

    NASA Astrophysics Data System (ADS)

    Islam, Md Rabiul; Guo, Youguang; Zhu, Jianguo

    2013-05-01

    Recent advances in magnetic materials have led to the development of compact and light weight, medium and high frequency transformers, which would be a possible solution to reducing the size and weight of wind turbine power generating systems. This paper presents the overall design and analysis of a Metglas amorphous alloy 2605SA1 based medium frequency transformer to generate the isolated balanced multiple DC supplies for medium voltage converter systems. A comprehensive electromagnetic analysis is conducted on the proposed design based on experimental results. The test stand, data analysis, and test results are discussed.

  10. 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.

  11. 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.

  12. Wind Turbines Benefit Crops

    SciTech Connect

    Takle, Gene

    2010-01-01

    Ames Laboratory associate scientist Gene Takle talks about research into the effect of wind turbines on nearby crops. Preliminary results show the turbines may have a positive effect by cooling and drying the crops and assisting with carbon dioxide uptake.

  13. Wind Turbine Blade

    USGS Multimedia Gallery

    This photo shows one of the three 135-ft blades of a turbine before installation. Although the blades of wind turbines appear to move quite slowly to the human eye, blade tips often move at speeds faster than 100 mph. ...

  14. Wind Turbines Benefit Crops

    ScienceCinema

    Takle, Gene

    2013-03-01

    Ames Laboratory associate scientist Gene Takle talks about research into the effect of wind turbines on nearby crops. Preliminary results show the turbines may have a positive effect by cooling and drying the crops and assisting with carbon dioxide uptake.

  15. Vertical Axis Wind Turbine

    Energy Science and Technology Software Center (ESTSC)

    2002-04-01

    Blade fatigue life is an important element in determining the economic viability of the Vertical-Axis Wind Turbine (VAWT). VAWT-SAL Vertical Axis Wind Turbine- Stochastic Aerodynamic Loads Ver 3.2 numerically simulates the stochastic (random0 aerodynamic loads of the Vertical-Axis Wind Turbine (VAWT) created by the atomspheric turbulence. The program takes into account the rotor geometry, operating conditions, and assumed turbulence properties.

  16. Wind turbine-generator

    SciTech Connect

    Kirschbaum, H.S.

    1981-09-22

    A wind-turbine generator system is described which transforms the rotational energy of a wind driven turbine blade into rotation in opposite directions of a rotor and a stator of a dynamoelectric machine to generate electrical power. A bevel gear rotating with the turbine blade drives two pinion gears and associated concentric shafts in opposite directions. The two shafts combine with a planetary gear set to provide the desired oppositely directed rotation. One of the shafts is associated with a ring carrier and drives a ring gear in one rotational direction. The other shaft drives a planet carrier in the opposite rotational direction. The planetary gear set is arranged such that a sun gear is driven in the direction opposite to that of the ring gear. A rotor is affixed to the sun gear by a spider support structure, and a stator, affixed to rotate with the ring gear, surrounds the rotor. The rotor and stator are thus rotated in opposite, mechanically and electrically additive, directions.

  17. 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.

  18. Wind turbine rotor assembly

    SciTech Connect

    Kaiser, H. W.

    1984-11-20

    A vertical axis wind turbine having a horizontal arm member which supports an upright blade assembly. Bearing structure coupling the blade assembly to the turbine arm permits blade movement about its longitudinal axis as well as flexing motion of the blade assembly about axes perpendicular to the longitudinal axis. A latching mechanism automatically locks the blade assembly to its supporting arm during normal turbine operation and automatically unlocks same when the turbine is at rest. For overspeed prevention, a centrifugally actuated arm functions to unlatch the blade assembly permitting same to slipstream or feather into the wind. Manually actuated means are also provided for unlatching the moving blade assembly. The turbine arm additionally carries a switching mechanism in circuit with a turbine generator with said mechanism functioning to open and hence protect the generator circuit in the event of an overspeed condition of the turbine.

  19. Coalescing Wind Turbine Wakes

    NASA Astrophysics Data System (ADS)

    Lee, S.; Churchfield, M.; Sirnivas, S.; Moriarty, P.; Nielsen, F. G.; Skaare, B.; Byklum, E.

    2015-06-01

    A team of researchers from the National Renewable Energy Laboratory and Statoil used large-eddy simulations to numerically investigate the merging wakes from upstream offshore wind turbines. Merging wakes are typical phenomena in wind farm flows in which neighboring turbine wakes consolidate to form complex flow patterns that are as yet not well understood. In the present study, three 6-MW turbines in a row were subjected to a neutrally stable atmospheric boundary layer flow. As a result, the wake from the farthest upstream turbine conjoined the downstream wake, which significantly altered the subsequent velocity deficit structures, turbulence intensity, and the global meandering behavior. The complexity increased even more when the combined wakes from the two upstream turbines mixed with the wake generated by the last turbine, thereby forming a “triplet” structure. Although the influence of the wake generated by the first turbine decayed with downstream distance, the mutated wakes from the second turbine continued to influence the downstream wake. Two mirror-image angles of wind directions that yielded partial wakes impinging on the downstream turbines yielded asymmetric wake profiles that could be attributed to the changing flow directions in the rotor plane induced by the Coriolis force. The turbine wakes persisted for extended distances in the present study, which is a result of low aerodynamic surface roughness typically found in offshore conditions.

  20. Piezoelectric wind turbine

    NASA Astrophysics Data System (ADS)

    Kishore, Ravi Anant; Priya, Shashank

    2013-03-01

    In past few years, there has been significant focus towards developing small scale renewable energy based power sources for powering wireless sensor nodes in remote locations such as highways and bridges to conduct continuous health monitoring. These prior efforts have led to the development of micro-scale solar modules, hydrogen fuel cells and various vibration based energy harvesters. However, the cost effectiveness, reliability, and practicality of these solutions remain a concern. Harvesting the wind energy using micro-to-small scale wind turbines can be an excellent solution in variety of outdoor scenarios provided they can operate at few miles per hour of wind speed. The conventional electromagnetic generator used in the wind mills always has some cogging torque which restricts their operation above certain cut-in wind speed. This study aims to develop a novel piezoelectric wind turbine that utilizes bimorph actuators for electro-mechanical energy conversion. This device utilizes a Savonius rotor that is connected to a disk having magnets at the periphery. The piezoelectric actuators arranged circumferentially around the disk also have magnets at the tip which interacts with the magnetic field of the rotating disk and produces cyclical deflection. The wind tunnel experiments were conducted between 2-12 mph of wind speeds to characterize and optimize the power output of the wind turbine. Further, testing was conducted in the open environment to quantify the response to random wind gusts. An attempt was made towards integration of the piezoelectric wind turbine with the wireless sensor node.

  1. Vertical axis wind turbines

    DOEpatents

    Krivcov, Vladimir (Miass, RU); Krivospitski, Vladimir (Miass, RU); Maksimov, Vasili (Miass, RU); Halstead, Richard (Rohnert Park, CA); Grahov, Jurij (Miass, RU)

    2011-03-08

    A vertical axis wind turbine is described. The wind turbine can include a top ring, a middle ring and a lower ring, wherein a plurality of vertical airfoils are disposed between the rings. For example, three vertical airfoils can be attached between the upper ring and the middle ring. In addition, three more vertical airfoils can be attached between the lower ring and the middle ring. When wind contacts the vertically arranged airfoils the rings begin to spin. By connecting the rings to a center pole which spins an alternator, electricity can be generated from wind.

  2. 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.

  3. Wind Turbine Acoustics

    NASA Technical Reports Server (NTRS)

    Hubbard, Harvey H.; Shepherd, Kevin P.

    2009-01-01

    Wind turbine generators, ranging in size from a few kilowatts to several megawatts, are producing electricity both singly and in wind power stations that encompass hundreds of machines. Many installations are in uninhabited areas far from established residences, and therefore there are no apparent environmental impacts in terms of noise. There is, however, the potential for situations in which the radiated noise can be heard by residents of adjacent neighborhoods, particularly those neighborhoods with low ambient noise levels. A widely publicized incident of this nature occurred with the operation of the experimental Mod-1 2-MW wind turbine, which is described in detail elsewhere. Pioneering studies which were conducted at the Mod-1 site on the causes and remedies of noise from wind turbines form the foundation of much of the technology described in this chapter.

  4. Wind Turbines on a Farm

    USGS Multimedia Gallery

    Scientists have found that wind turbines are causing fatalities of certain species of migratory insect-eating bats, although a March 2011 study in Science suggests that solutions to reduce the impacts of wind turbines on bats may be possible....

  5. Model Predictive Control Wind Turbines

    E-print Network

    Model Predictive Control of Wind Turbines Martin Klauco Kongens Lyngby 2012 IMM-MSc-2012-65 #12;Summary Wind turbines are the biggest part of the green energy industry. Increasing interest control strategies. Control strategy has a significant impact on the wind turbine operation on many levels

  6. 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.

  7. Airborne Wind Turbine

    SciTech Connect

    2010-09-01

    Broad Funding Opportunity Announcement Project: Makani Power is developing an Airborne Wind Turbine (AWT) that eliminates 90% of the mass of a conventional wind turbine and accesses a stronger, more consistent wind at altitudes of near 1,000 feet. At these altitudes, 85% of the country can offer viable wind resources compared to only 15% accessible with current technology. Additionally, the Makani Power wing can be economically deployed in deep offshore waters, opening up a resource which is 4 times greater than the entire U.S. electrical generation capacity. Makani Power has demonstrated the core technology, including autonomous launch, land, and power generation with an 8 meter wingspan, 20 kW prototype. At commercial scale, Makani Power aims to develop a 600 kW, 28 meter wingspan product capable of delivering energy at an unsubsidized cost competitive with coal, the current benchmark for low-cost power.

  8. Tornado type wind turbines

    SciTech Connect

    Hsu, Ch.-T.

    1984-06-05

    A tornado type wind turbine has a vertically disposed wind collecting tower with spaced apart inner and outer walls and a central bore. The upper end of the tower is open while the lower end of the structure is in communication with a wind intake chamber. An opening in the wind chamber is positioned over a turbine which is in driving communication with an electrical generator. An opening between the inner and outer walls at the lower end of the tower permits radially flowing air to enter the space between the inner and outer walls while a vertically disposed opening in the wind collecting tower permits tangentially flowing air to enter the central bore. A porous portion of the inner wall permits the radially flowing air to interact with the tangentially flowing air so as to create an intensified vortex flow which exits out of the top opening of the tower so as to create a low pressure core and thus draw air through the opening of the wind intake chamber so as to drive the turbine.

  9. Tornado type wind turbines

    DOEpatents

    Hsu, Cheng-Ting (Ames, IA)

    1984-01-01

    A tornado type wind turbine has a vertically disposed wind collecting tower with spaced apart inner and outer walls and a central bore. The upper end of the tower is open while the lower end of the structure is in communication with a wind intake chamber. An opening in the wind chamber is positioned over a turbine which is in driving communication with an electrical generator. An opening between the inner and outer walls at the lower end of the tower permits radially flowing air to enter the space between the inner and outer walls while a vertically disposed opening in the wind collecting tower permits tangentially flowing air to enter the central bore. A porous portion of the inner wall permits the radially flowing air to interact with the tangentially flowing air so as to create an intensified vortex flow which exits out of the top opening of the tower so as to create a low pressure core and thus draw air through the opening of the wind intake chamber so as to drive the turbine.

  10. Wind turbine spoiler

    DOEpatents

    Sullivan, William N. (Albuquerque, NM)

    1985-01-01

    An aerodynamic spoiler system for a vertical axis wind turbine includes spoilers on the blades initially stored near the rotor axis to minimize drag. A solenoid latch adjacent the central support tower releases the spoilers and centrifugal force causes the spoilers to move up the turbine blades away from the rotor axis, thereby producing a braking effect and actual slowing of the associated wind turbine, if desired. The spoiler system can also be used as an infinitely variable power control by regulated movement of the spoilers on the blades over the range between the undeployed and fully deployed positions. This is done by the use of a suitable powered reel and cable located at the rotor tower to move the spoilers.

  11. Advanced wind turbine conceptual study

    NASA Astrophysics Data System (ADS)

    1995-07-01

    Objective was to develop improvements to an existing wind turbine that would make wind energy more competitive in 1993-1995, and to initiate studies of an advanced wind turbine configuration that would make wind energy competitive for bulk electricity generation by 1998-2000. Objective has been achieved.

  12. Wind Turbine Dynamics

    NASA Technical Reports Server (NTRS)

    Thresher, R. W. (editor)

    1981-01-01

    Recent progress in the analysis and prediction of the dynamic behavior of wind turbine generators is discussed. The following areas were addressed: (1) the adequacy of state of the art analysis tools for designing the next generation of wind power systems; (2) the use of state of the art analysis tools designers; and (3) verifications of theory which might be lacking or inadequate. Summaries of these informative discussions as well as the questions and answers which followed each paper are documented in the proceedings.

  13. Airfoils for wind turbine

    DOEpatents

    Tangler, James L. (Boulder, CO); Somers, Dan M. (State College, PA)

    1996-01-01

    Airfoils for the blade of a wind turbine wherein each airfoil is characterized by a thickness in a range from 16%-24% and a maximum lift coefficient designed to be largely insensitive to roughness effects. The airfoils include a family of airfoils for a blade 15 to 25 meters in length, a family of airfoils for a blade 1 to 5 meters in length, and a family of airfoils for a blade 5 to 10 meters in length.

  14. Airfoils for wind turbine

    DOEpatents

    Tangler, J.L.; Somers, D.M.

    1996-10-08

    Airfoils are disclosed for the blade of a wind turbine wherein each airfoil is characterized by a thickness in a range from 16%-24% and a maximum lift coefficient designed to be largely insensitive to roughness effects. The airfoils include a family of airfoils for a blade 15 to 25 meters in length, a family of airfoils for a blade 1 to 5 meters in length, and a family of airfoils for a blade 5 to 10 meters in length. 10 figs.

  15. Sandhill Cranes Near Wind Turbines

    USGS Multimedia Gallery

    Sandhill Cranes fly in close proximity to wind turbines near Horicon National Wildlife Refuge in east-central Wisconsin, but to date no crane mortality has been associated with turbines in this area....

  16. Composite wind turbine blades

    NASA Astrophysics Data System (ADS)

    Ong, Cheng-Huat

    Researchers in wind energy industry are constantly moving forward to develop higher efficiency wind turbine. One major component for wind turbine design is to have cost effective wind turbine blades. In addition to correct aerodynamic shape and blade geometry, blade performance can be enhanced further through aero-elastic tailoring design and material selections. An analytical tool for blade design has been improved and validated. This analytical tool is utilized to resolve issues related to elastic tailoring design. The investigation looks into two major issues related to the design and fabrication of a bend-twist-coupled blade. Various design parameters for a blade such as materials, laminate lay-up, skin thickness, ply orientation, internal spar, etc. have been examined for designing a bend-twist-coupled blade. The parametric study indicates that the critical design parameters are the ply material, the ply orientation, and the volume fraction ratio between the anisotropic layers and orthotropic layers. To produce a blade having the bend-twist coupling characteristics, the fiber lay-ups at the top and bottom skins of the blade must have a "mirror" lay-up in relation to the middle plane of the blade. Such lay-up causes fiber discontinuation at the seam. The joint design at the seam is one major consideration in fabricating a truly anisotropic blade. A new joint design was proposed and tensile failure tests were carried out for both the old and new joint designs. The tests investigated the effects of different types of joint designs, the laminate lay-up at the joints, and the stacking sequence of the joint retention strength. A major component of a wind turbine blade, D-spar, was designed to maximum coupling. Two D-spars were then fabricated using the new joint design; one of them was subjected to both static and modal testings. Traditionally, wind turbine blades are made of low cost glass material; however, carbon fibers are proposed as alternative material. Our study indicates that carbon fibers are more efficient than glass fibers not only in blade structural performance, but also in relative cost comparison.

  17. Superconducting wind turbine generators

    NASA Astrophysics Data System (ADS)

    Abrahamsen, A. B.; Mijatovic, N.; Seiler, E.; Zirngibl, T.; Træholt, C.; Nørgård, P. B.; Pedersen, N. F.; Andersen, N. H.; Østergård, J.

    2010-03-01

    We have examined the potential of 10 MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future offshore turbines of 8 and 10 MW have been determined from an up-scaling of an existing 5 MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However, the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10 kW, 100 kW, 1 MW and 10 MW is suggested to secure the accumulation of reliability experience. Finally, the quantities of high temperature superconducting tape needed for a 10 kW and an extreme high field 10 MW generator are found to be 7.5 km and 1500 km, respectively. A more realistic estimate is 200-300 km of tape per 10 MW generator and it is concluded that the present production capacity of coated conductors must be increased by a factor of 36 by 2020, resulting in a ten times lower price of the tape in order to reach a realistic price level for the superconducting drive train.

  18. 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.

  19. Damage Detection in Wind Turbine Towers using a Finite Element Model and Discrete Wavelet Transform of Strain Signals

    NASA Astrophysics Data System (ADS)

    Kenna, A.; Basu, B.

    2015-07-01

    Wind turbine support towers at heights in excess of 90m are nowadays being formed in steel, concrete and hybrid concrete and steel structures. As is the case for all towers of this height, the towers will be assembled using a number of segments, which will be connected in some way. These local connections are to be viewed as areas of potential local weakness in the overall tower assembly and require care in terms of design and construction. This work concentrates on identifying local damage which can occur at an interface connection by either material or bolt/tendon failure. Spatial strain patterns will be used to try to identify local damage areas around a 3 dimensional tower shell. A Finite Element (FE) model will be assembled which will describe a hybrid tower as a continuum of four-noded, two-dimensional Reisser- Mindlin shell elements. In order to simulate local damage, an element around the circumference of the tower interface will be subjected to a reduced stiffness. Strain patterns will be observed both in the undamaged and damaged states and these signals will be processed using a Discrete Wavelet Transform (DWT) algorithm to investigate if the damaged element can be identified.

  20. Wind Turbine Development: Press release

    SciTech Connect

    Not Available

    1994-05-09

    The US Department of Energy (DOE) has announced a new partnership with Zond Systems, Inc., of Tehachapi, California. The partnership is the firs to be announced under DOE`s new Value-Engineered Turbine (VET) project. The VET project is expected to lower the cost of manufacturing wind turbines and give the US wind industry a competitive boost.

  1. Vertical wind turbine

    SciTech Connect

    Danson, D.P.

    1988-08-16

    This patent describes a wind driven turbine of the vertical axis type comprising: (a) a support base; (b) a generally vertical column rotatably mounted to the support base; (c) upper and lower support means respectively mounted on the column for rotation therewith; wind driven blades connected between the upper and lower support means for rotation about the column and each blade being individually rotatable about a blade axis extending longitudinally through the blade to vary a blade angle of attach thereof relative to wind velocity during rotation about the column; and (e) control means for variably adjusting angles of attack of each blade to incident wind, the control means including a connecting rod means having drive means for rotating each blade about the associated blade axis in response to radial movement of the connecting rod means and control shaft pivotally mounted within the column and having a first shaft portion connected to the connecting rod means and a second shaft portion radially offset from the first shaft portion and pivotally connected to radially displace the first portion and thereby the connecting rod means to vary the blade angles of attack during rotation about the column.

  2. Iterative generalized synchrosqueezing transform for fault diagnosis of wind turbine planetary gearbox under nonstationary conditions

    NASA Astrophysics Data System (ADS)

    Feng, Zhipeng; Chen, Xiaowang; Liang, Ming

    2015-02-01

    The synchrosqueezing transform can effectively improve the readability of time-frequency representation of mono-component and constant frequency signals. However, for multi-component and time-variant frequency signals, it still suffers from time-frequency blurs. In order to address this issue, the synchrosqueezing transform is improved using iterative generalized demodulation. Firstly, the complex nonstationary signal is decomposed into mono-components of constant frequency by iterative generalized demodulation. Then, the instantaneous frequency of each mono-component is accurately estimated via the synchrosqueezing transform, by exploiting its merit of enhanced time-frequency resolution. Finally, the time-frequency representation of the original signal is obtained by superposing the time-frequency representations of all the mono-components with restored instantaneous frequency. This proposed method generalizes the synchrosqueezing transform to multi-component and time-variant frequency signals, and it has fine time-frequency resolution and is free of cross-term interferences. The proposed method was validated using both numerically simulated and lab experimental vibration signals of planetary gearboxes under nonstationary conditions. The time-variant planetary gearbox characteristic frequencies were effectively identified, and the gear faults were correctly diagnosed.

  3. Wind turbine rotor aileron

    DOEpatents

    Coleman, Clint (Warren, VT); Kurth, William T. (Warren, VT)

    1994-06-14

    A wind turbine has a rotor with at least one blade which has an aileron which is adjusted by an actuator. A hinge has two portions, one for mounting a stationary hinge arm to the blade, the other for coupling to the aileron actuator. Several types of hinges can be used, along with different actuators. The aileron is designed so that it has a constant chord with a number of identical sub-assemblies. The leading edge of the aileron has at least one curved portion so that the aileron does not vent over a certain range of angles, but vents if the position is outside the range. A cyclic actuator can be mounted to the aileron to adjust the position periodically. Generally, the aileron will be adjusted over a range related to the rotational position of the blade. A method for operating the cyclic assembly is also described.

  4. Aerodynamic and aeroacoustic for wind turbine

    SciTech Connect

    Mohamed, Maizi; Rabah, Dizene

    2015-03-10

    This paper describes a hybrid approach forpredicting noise radiated from the rotating Wind Turbine (HAWT) blades, where the sources are extracted from an unsteady Reynolds-Averaged-Navier Stocks (URANS) simulation, ANSYS CFX 11.0, was used to calculate The near-field flow parameters around the blade surface that are necessary for FW-H codes. Comparisons with NREL Phase II experimental results are presented with respect to the pressure distributions for validating a capacity of the solver to calculate the near-field flow on and around the wind turbine blades, The results show that numerical data have a good agreement with experimental. The acoustic pressure, presented as a sum of thickness and loading noise components, is analyzed by means of a discrete fast Fourier transformation for the presentation of the time acoustic time histories in the frequency domain. The results convincingly show that dipole source noise is the dominant noise source for this wind turbine.

  5. Diffuser Augmented Wind Turbine Analysis Code

    E-print Network

    Carroll, Jonathan

    2014-05-31

    , it is necessary to develop innovative wind capturing devices that can produce energy in the locations where large conventional horizontal axis wind turbines (HAWTs) are too impractical to install and operate. A diffuser augmented wind turbine (DAWT) is one...

  6. Parametric design of floating wind turbines

    E-print Network

    Tracy, Christopher (Christopher Henry)

    2007-01-01

    As the price of energy increases and wind turbine technology matures, it is evident that cost effective designs for floating wind turbines are needed. The next frontier for wind power is the ocean, yet development in near ...

  7. Wind and solar powered turbine

    NASA Technical Reports Server (NTRS)

    Wells, I. D.; Koh, J. L.; Holmes, M. (inventors)

    1984-01-01

    A power generating station having a generator driven by solar heat assisted ambient wind is described. A first plurality of radially extendng air passages direct ambient wind to a radial flow wind turbine disposed in a centrally located opening in a substantially disc-shaped structure. A solar radiation collecting surface having black bodies is disposed above the fist plurality of air passages and in communication with a second plurality of radial air passages. A cover plate enclosing the second plurality of radial air passages is transparent so as to permit solar radiation to effectively reach the black bodies. The second plurality of air passages direct ambient wind and thermal updrafts generated by the black bodies to an axial flow turbine. The rotating shaft of the turbines drive the generator. The solar and wind drien power generating system operates in electrical cogeneration mode with a fuel powered prime mover.

  8. MOD-2 wind turbine development

    NASA Technical Reports Server (NTRS)

    Gordon, L. H.; Andrews, J. S.; Zimmerman, D. K.

    1983-01-01

    The development of the Mod-2 turbine, designed to achieve a cost of electricity for the 100th production unit that will be competitive with conventional electric power generation is discussed. The Mod-2 wind turbine system (WTS) background, project flow, and a chronology of events and problem areas leading to Mod-2 acceptance are addressed. The role of the participating utility during site preparation, turbine erection and testing, remote operation, and routine operation and maintenance activity is reviewed. The technical areas discussed pertain to system performance, loads, and controls. Research and technical development of multimegawatt turbines is summarized.

  9. Airfoils for wind turbine

    DOEpatents

    Tangler, James L. (Boulder, CO); Somers, Dan M. (State College, PA)

    2000-01-01

    Airfoils for the tip and mid-span regions of a wind turbine blade have upper surface and lower surface shapes and contours between a leading edge and a trailing edge that minimize roughness effects of the airfoil and provide maximum lift coefficients that are largely insensitive to roughness effects. The airfoil in one embodiment is shaped and contoured to have a thickness in a range of about fourteen to seventeen percent, a Reynolds number in a range of about 1,500,000 to 2,000,000, and a maximum lift coefficient in a range of about 1.4 to 1.5. In another embodiment, the airfoil is shaped and contoured to have a thickness in a range of about fourteen percent to sixteen percent, a Reynolds number in a range of about 1,500,000 to 3,000,000, and a maximum lift coefficient in a range of about 0.7 to 1.5. Another embodiment of the airfoil is shaped and contoured to have a Reynolds in a range of about 1,500,000 to 4,000,000, and a maximum lift coefficient in a range of about 1.0 to 1.5.

  10. Rotationally sampled wind characteristics and correlations with MOD-OA wind turbine response

    SciTech Connect

    George, R.L.; Connell, J.R.

    1984-09-01

    This report presents results of a comprehensive wind and wind turbine measurement program: the Clayton, New Mexico, vertical plane array/MOD-OA project. In this experiment, the turbulent wind was measured for a large array of fixed anemometers located two blade diameters upwind of a 200-kW horizontal-axis wind turbine (HAWT). Simultaneously, key wind turbine response parameters were also measured. The first of two major objectives of this experiment was to determine the turbulent wind, rotationally sampled to emulate the motion of the wind turbine blade, for the range of different wind speeds and stability classes actually experienced by the wind turbine. The second major objective was to correlate this rotationally sampled wind with the wind turbine blade stress and power, in order to assess the usefulness of the wind measurements for wind turbine loads testing a prediction. Time series of rotationally sampled winds and wind turbine blade bending moments and power were converted to frequency spectra using Fourier transform techniques. These spectra were used as the basis for both qualitative and quantitative comparisons among the various cases. A quantitative comparison between the rotationally sampled wind input and blade bending response was made, using the Fourier spectra to estimate the blade transfer function. These transfer functions were then used to calculate an approximate damping coefficient for the MOD-OA fiberglass blade.

  11. Foundations for offshore wind turbines.

    PubMed

    Byrne, B W; Houlsby, G T

    2003-12-15

    An important engineering challenge of today, and a vital one for the future, is to develop and harvest alternative sources of energy. This is a firm priority in the UK, with the government setting a target of 10% of electricity from renewable sources by 2010. A component central to this commitment will be to harvest electrical power from the vast energy reserves offshore, through wind turbines or current or wave power generators. The most mature of these technologies is that of wind, as much technology transfer can be gained from onshore experience. Onshore wind farms, although supplying 'green energy', tend to provoke some objections on aesthetic grounds. These objections can be countered by locating the turbines offshore, where it will also be possible to install larger capacity turbines, thus maximizing the potential of each wind farm location. This paper explores some civil-engineering problems encountered for offshore wind turbines. A critical component is the connection of the structure to the ground, and in particular how the load applied to the structure is transferred safely to the surrounding soil. We review previous work on the design of offshore foundations, and then present some simple design calculations for sizing foundations and structures appropriate to the wind-turbine problem. We examine the deficiencies in the current design approaches, and the research currently under way to overcome these deficiencies. Designs must be improved so that these alternative energy sources can compete economically with traditional energy suppliers. PMID:14667305

  12. Wind Turbines Electrical and Mechanical Engineering

    E-print Network

    Provancher, William

    Wind Turbines Electrical and Mechanical Engineering Objective · Introduce students to the concept of alternative energy. · Explain the math and scientific principles behind engineering wind turbines. Standards and how it applies to wind energy · About how surface area and shape effects wind turbine efficiency

  13. A Fatigue Approach to Wind Turbine Control

    E-print Network

    A Fatigue Approach to Wind Turbine Control Keld Hammerum Kongens Lyngby 2006 #12;Technical to the turbulent nature of wind, the structural components of a wind turbine are exposed to highly varying loads. Therefore, fatigue damage is a major consideration when designing wind turbines. The control scheme applied

  14. 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.

  15. Sandia Wind Turbine Loads Database

    DOE Data Explorer

    The Sandia Wind Turbine Loads Database is divided into six files, each corresponding to approximately 16 years of simulation. The files are text files with data in columnar format. The 424MB zipped file containing six data files can be downloaded by the public. The files simulate 10-minute maximum loads for the NREL 5MW wind turbine. The details of the loads simulations can be found in the paper: “Decades of Wind Turbine Loads Simulations”, M. Barone, J. Paquette, B. Resor, and L. Manuel, AIAA2012-1288 (3.69MB PDF). Note that the site-average wind speed is 10 m/s (class I-B), not the 8.5 m/s reported in the paper.

  16. Energy 101: Wind Turbines - 2014 Update

    ScienceCinema

    None

    2014-06-05

    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.

  17. Energy 101: Wind Turbines - 2014 Update

    SciTech Connect

    2014-05-06

    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.

  18. Wind Turbines and Human Health

    PubMed Central

    Knopper, Loren D.; Ollson, Christopher A.; McCallum, Lindsay C.; Whitfield Aslund, Melissa L.; Berger, Robert G.; Souweine, Kathleen; McDaniel, Mary

    2014-01-01

    The association between wind turbines and health effects is highly debated. Some argue that reported health effects are related to wind turbine operation [electromagnetic fields (EMF), shadow flicker, audible noise, low-frequency noise, infrasound]. Others suggest that when turbines are sited correctly, effects are more likely attributable to a number of subjective variables that result in an annoyed/stressed state. In this review, we provide a bibliographic-like summary and analysis of the science around this issue specifically in terms of noise (including audible, low-frequency noise, and infrasound), EMF, and shadow flicker. Now there are roughly 60 scientific peer-reviewed articles on this issue. The available scientific evidence suggests that EMF, shadow flicker, low-frequency noise, and infrasound from wind turbines are not likely to affect human health; some studies have found that audible noise from wind turbines can be annoying to some. Annoyance may be associated with some self-reported health effects (e.g., sleep disturbance) especially at sound pressure levels >40?dB(A). Because environmental noise above certain levels is a recognized factor in a number of health issues, siting restrictions have been implemented in many jurisdictions to limit noise exposure. These setbacks should help alleviate annoyance from noise. Subjective variables (attitudes and expectations) are also linked to annoyance and have the potential to facilitate other health complaints via the nocebo effect. Therefore, it is possible that a segment of the population may remain annoyed (or report other health impacts) even when noise limits are enforced. Based on the findings and scientific merit of the available studies, the weight of evidence suggests that when sited properly, wind turbines are not related to adverse health. Stemming from this review, we provide a number of recommended best practices for wind turbine development in the context of human health. PMID:24995266

  19. Wind turbines and human health.

    PubMed

    Knopper, Loren D; Ollson, Christopher A; McCallum, Lindsay C; Whitfield Aslund, Melissa L; Berger, Robert G; Souweine, Kathleen; McDaniel, Mary

    2014-01-01

    The association between wind turbines and health effects is highly debated. Some argue that reported health effects are related to wind turbine operation [electromagnetic fields (EMF), shadow flicker, audible noise, low-frequency noise, infrasound]. Others suggest that when turbines are sited correctly, effects are more likely attributable to a number of subjective variables that result in an annoyed/stressed state. In this review, we provide a bibliographic-like summary and analysis of the science around this issue specifically in terms of noise (including audible, low-frequency noise, and infrasound), EMF, and shadow flicker. Now there are roughly 60 scientific peer-reviewed articles on this issue. The available scientific evidence suggests that EMF, shadow flicker, low-frequency noise, and infrasound from wind turbines are not likely to affect human health; some studies have found that audible noise from wind turbines can be annoying to some. Annoyance may be associated with some self-reported health effects (e.g., sleep disturbance) especially at sound pressure levels >40?dB(A). Because environmental noise above certain levels is a recognized factor in a number of health issues, siting restrictions have been implemented in many jurisdictions to limit noise exposure. These setbacks should help alleviate annoyance from noise. Subjective variables (attitudes and expectations) are also linked to annoyance and have the potential to facilitate other health complaints via the nocebo effect. Therefore, it is possible that a segment of the population may remain annoyed (or report other health impacts) even when noise limits are enforced. Based on the findings and scientific merit of the available studies, the weight of evidence suggests that when sited properly, wind turbines are not related to adverse health. Stemming from this review, we provide a number of recommended best practices for wind turbine development in the context of human health. PMID:24995266

  20. Vertical axis wind turbine airfoil

    DOEpatents

    Krivcov, Vladimir; Krivospitski, Vladimir; Maksimov, Vasili; Halstead, Richard; Grahov, Jurij Vasiljevich

    2012-12-18

    A vertical axis wind turbine airfoil is described. The wind turbine airfoil can include a leading edge, a trailing edge, an upper curved surface, a lower curved surface, and a centerline running between the upper surface and the lower surface and from the leading edge to the trailing edge. The airfoil can be configured so that the distance between the centerline and the upper surface is the same as the distance between the centerline and the lower surface at all points along the length of the airfoil. A plurality of such airfoils can be included in a vertical axis wind turbine. These airfoils can be vertically disposed and can rotate about a vertical axis.

  1. Wind Turbine Generator KanaKanapathipillai

    E-print Network

    New South Wales, University of

    Wind Turbine Generator Noise KanaKanapathipillai Reliable and accurate measurement of wind turbine generator noise in wind farms has been a challenge for acoustic engineers due to the constant presence of fluctuation in wind speed and turbulence along with the presence of background noise. With wind farms gaining

  2. Bats and offshore wind turbines studied in

    E-print Network

    Bats and offshore wind turbines studied in southern Scandinavia report 5571 · july 2007 #12;Bats Ahlén Digital publication #12;VINDVAL Report 5571 - Bats and offshore wind turbines studied in southern;VINDVAL Report 5571 - Bats and offshore wind turbines studied in southern Scandinavia 4 #12;VINDVAL Report

  3. Built Environment Wind Turbine Roadmap

    SciTech Connect

    Smith, J.; Forsyth, T.; Sinclair, K.; Oteri, F.

    2012-11-01

    The market currently encourages BWT deployment before the technology is ready for full-scale commercialization. To address this issue, industry stakeholders convened a Rooftop and Built-Environment Wind Turbine Workshop on August 11 - 12, 2010, at the National Wind Technology Center, located at the U.S. Department of Energy’s National Renewable Energy Laboratory in Boulder, Colorado. This report summarizes the workshop.

  4. Wind turbine testing. Final report

    SciTech Connect

    Smith, P.R.

    1995-01-01

    Los Alamos National Laboratory (LANL) is investigating concepts for removing heat from nuclear material storage units. One method which has been suggested is the use of wind turbine ventilators on the roofs of the units. An advantage of these devices is that it would require no power to operate them, and in this sense the system would be fail safe. The internal heat in the storage units would naturally cause air to rise through the ventilators and the usually prevailing winds which average about 5 mph would combine with the buoyancy to exhaust the air from the units. However, it was not known whether these type of ventilators can deliver a sufficient air flow through the High Efficiency Particulate Air (HEPA) filters which must be an integral part of the ventilation system in a nuclear storage facility. Therefore, this study was undertaken to answer that question. In this report we will discuss the experiments which were run on two wind turbine ventilators, one with a one foot diameter inlet duct and one with a two foot diameter inlet duct. The wind turbines were supplied by LANL and tested in the New Mexico State University/LANL wind binnel housed in the Mechanical Engineering Department on the Las Cruces Campus of NMSU. The experiments were run at a nominal wind speed of 5 mph, with and without heating below the ventilator inlet and with and without resistance elements at the ventilator inlet.

  5. Inertial response from wind turbines

    NASA Astrophysics Data System (ADS)

    Moore, Ian F.

    Wind power is an essential part of the strategy to address challenges facing the energy sector. Operation of the electricity network in 2020 will require higher levels of response and reserve from generation. The provision of inertial response from wind turbines was investigated. A model was developed for the simulation of frequency on the mainland UK system, including a simplified model for a synchronous generator to represent Full Power Converter turbines. Two different methods of inertia response, the step method and the inertia coupling method, were modelled and introduced into the turbine torque speed control. Simulations illustrated the effects on primary frequency control for a high penetration of wind turbines. Results are shown for different demand levels with generation losses of 1320GW and 1800GW. A comparison of the inertia functions is included and the effect of wind speed and the constant speed region of the maximum power extraction curve. For the scenarios modelled only a small change in turbine output was required for inertia response (0.02p.u). Without inertia response a large increase in synchronous plant response was needed. A test rig was constructed consisting of a Full Power Converter bridge and a synchronous generator driven by a dc machine. Power converters were designed and constructed by the candidate. Vector control of both the generator converter and grid converter was implemented on a dedicated control platform. The inertia coupling function was implemented and a test frequency deviation injected to represent a load generation imbalance. Results compared closely to those from the model and demonstrated the capability to closely couple turbine speed to system frequency with adjustment of the response via a filter if desired. The experimental work confirmed the adequacy of the simplified generator model and further confirmed the possibility of using inertia response. The inertia coupling function was considered suitable for use for the UK system.

  6. Estimation of Wind Speed in Connection to a Wind Turbine

    E-print Network

    Estimation of Wind Speed in Connection to a Wind Turbine X. Ma #3; , N. K. Poulsen #3; , H. Bindner y December 20, 1995 Abstract The wind speed varies over the rotor plane of wind turbine making it impossible to determine from a single wind speed measurement taken by an anemometer. However, in this paper

  7. Fixture for winding transformers

    NASA Technical Reports Server (NTRS)

    Mclyman, M. T.

    1980-01-01

    Bench-mounted fixture assists operator in winding toroid-shaped transformer cores. Toroid is rigidly held in place as wires are looped around. Arrangement frees both hands for rapid winding and untangling of wires that occurs when core is hand held.

  8. 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.

  9. Comparison of field and wind tunnel Darrieus wind turbine data

    SciTech Connect

    Sheldahl, R.E.

    1981-01-01

    A 2-m-dia Darrieus Vertical Axis Wind Turbine with NACA-0012 blades was extensively tested in the Vought Corporation Low Speed Wind Tunnel. This same turbine was installed in the field at the Sandia National Laboratories Wind Turbine Test Site and operated to determine if field data corresponded to data obtained in the wind tunnel. It is believed that the accuracy of the wind tunnel test data was verified and thus the credibility of that data base was further established.

  10. Advanced controls for floating wind turbines

    E-print Network

    Casanovas, Carlos (Casanovas Bermejo)

    2014-01-01

    Floating Offshore Wind Turbines (FOWT) is a technology that stands to spearhead the rapid growth of the offshore wind energy sector and allow the exploration of vast high quality wind resources over coastal and offshore ...

  11. 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.

  12. AWEA Small Wind Turbine Global Market Study

    E-print Network

    Leu, Tzong-Shyng "Jeremy"

    AWEA Small Wind Turbine Global Market Study YEAR ENDING 2009 #12;Summary 3 Survey Findings Resources 28 Endnotes 30 Table of Contents #12;2010 SMAll WInD TuRBInE GlOBAl MARkET STuDy | 3 Small Wind wind turbines ­ those with rated capacities of 100 kilowatts (kW)1 and less ­ grew 15% in 2009 with 20

  13. Computational Analysis of Shrouded Wind Turbine Configurations

    E-print Network

    Alonso, Juan J.

    Computational Analysis of Shrouded Wind Turbine Configurations Aniket C. Aranake Vinod K. Lakshminarayan Karthik Duraisamy Computational analysis of diuser-augmented turbines is performed using high-dimensional simulations of shrouded wind turbines are performed for selected shroud geometries. The results are compared

  14. On the Fatigue Analysis of Wind Turbines

    SciTech Connect

    Sutherland, Herbert J.

    1999-06-01

    Modern wind turbines are fatigue critical machines that are typically used to produce electrical power from the wind. Operational experiences with these large rotating machines indicated that their components (primarily blades and blade joints) were failing at unexpectedly high rates, which led the wind turbine community to develop fatigue analysis capabilities for wind turbines. Our ability to analyze the fatigue behavior of wind turbine components has matured to the point that the prediction of service lifetime is becoming an essential part of the design process. In this review paper, I summarize the technology and describe the ''best practices'' for the fatigue analysis of a wind turbine component. The paper focuses on U.S. technology, but cites European references that provide important insights into the fatigue analysis of wind turbines.

  15. Wind Turbine Manufacturing Process Monitoring

    SciTech Connect

    Waseem Faidi; Chris Nafis; Shatil Sinha; Chandra Yerramalli; Anthony Waas; Suresh Advani; John Gangloff; Pavel Simacek

    2012-04-26

    To develop a practical inline inspection that could be used in combination with automated composite material placement equipment to economically manufacture high performance and reliable carbon composite wind turbine blade spar caps. The approach technical feasibility and cost benefit will be assessed to provide a solid basis for further development and implementation in the wind turbine industry. The program is focused on the following technology development: (1) Develop in-line monitoring methods, using optical metrology and ultrasound inspection, and perform a demonstration in the lab. This includes development of the approach and performing appropriate demonstration in the lab; (2) Develop methods to predict composite strength reduction due to defects; and (3) Develop process models to predict defects from leading indicators found in the uncured composites.

  16. Wind Turbine Generator System Acoustic Noise Test Report for the Gaia Wind 11-kW Wind Turbine

    SciTech Connect

    Huskey, A.

    2011-11-01

    This report details the acoustic noise test conducted on the Gaia-Wind 11-kW wind turbine at the National Wind Technology Center. The test turbine is a two- bladed, downwind wind turbine with a rated power of 11 kW. The test turbine was tested in accordance with the International Electrotechnical Commission standard, IEC 61400-11 Ed 2.1 2006-11 Wind Turbine Generator Systems -- Part 11 Acoustic Noise Measurement Techniques.

  17. Fast Wind Turbine Design via Geometric Programming

    E-print Network

    Abbeel, Pieter

    Fast Wind Turbine Design via Geometric Programming Warren Hoburg and Pieter Abbeel UC Berkeley introduces the (perhaps surprising) discovery that a number of prevailing physics-based models for wind the application of GP to large wind turbine design problems a promising approach. Nomenclature (·)a, (·)t axial

  18. Development of 1 MW wind turbine

    SciTech Connect

    Osada, Isamu; Takatsuka, Hiromu; Nomiyama, Yutaka; Kato, Eiji

    1999-07-01

    Regarding wind turbine development, European countries especially Germany and Denmark are front runners. The Japanese Government is also promoting its installation domestically and for developing countries through various kinds of financial supports. This requirement also accelerated scale-up of wind turbines because a larger wind turbine produces more power per site area and is expected to be a lower initial cost per kW. According to these market needs, MHI has developed a 1MW class wind turbine generator, which covers from 800kW to 1,200kW. The first unit of 1MW is under manufacture and will be commissioned by the end of April 1999. This paper describes the features of the authors 1MW wind turbine, along with their experiences on scale-up of a wind turbine generator.

  19. Small Wind Research Turbine: Final Report

    SciTech Connect

    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.

  20. Wind Turbine Generator System Safety and Function Test Report for the Entegrity EW50 Wind Turbine

    SciTech Connect

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

    2012-11-01

    This report summarizes the results of a safety and function 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.

  1. Wind Turbine Generator System Safety and Function Test Report for the Ventera VT10 Wind Turbine

    SciTech Connect

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

    2012-11-01

    This report summarizes the results of a safety and function test that NREL conducted on the Ventera VT10 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.

  2. 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.

  3. Vertical-axis wind-turbine program

    SciTech Connect

    Braasch, R.H.

    1981-01-01

    During the interval since the Fourth Biennial Wind Energy Conference, the vertical axis wind turbine program has experienced significant progress. The purpose of this paper is to review that progress in aerodynamics research, structural dynamics research, and machine development.

  4. Wind Turbine Generator System Power Performance Test Report for the ARE442 Wind Turbine

    SciTech Connect

    van Dam, J.; Jager, D.

    2010-02-01

    This report summarizes the results of a power performance test that NREL conducted on the ARE 442 wind turbine. This test was conducted in accordance with the International Electrotechnical Commission's (IEC) standard, Wind Turbine Generator Systems Part 12: Power Performance Measurements of Electricity Producing Wind Turbines, IEC 61400-12-1 Ed.1.0, 2005-12. However, because the ARE 442 is a small turbine as defined by IEC, NREL also followed Annex H that applies to small wind turbines. In these summary results, wind speed is normalized to sea-level air density.

  5. Microprocessor control of a wind turbine generator

    NASA Technical Reports Server (NTRS)

    Gnecco, A. J.; Whitehead, G. T.

    1978-01-01

    A microprocessor based system was used to control the unattended operation of a wind turbine generator. The turbine and its microcomputer system are fully described with special emphasis on the wide variety of tasks performed by the microprocessor for the safe and efficient operation of the turbine. The flexibility, cost and reliability of the microprocessor were major factors in its selection.

  6. Aerodynamic interference between two Darrieus wind turbines

    SciTech Connect

    Schatzle, P.R.; Klimas, P.C.; Spahr, H.R.

    1981-04-01

    The effect of aerodynamic interference on the performance of two curved bladed Darrieus-type vertical axis wind turbines has been calculated using a vortex/lifting line aerodynamic model. The turbines have a tower-to-tower separation distance of 1.5 turbine diameters, with the line of turbine centers varying with respect to the ambient wind direction. The effects of freestream turbulence were neglected. For the cases examined, the calculations showed that the downwind turbine power decrement (1) was significant only when the line of turbine centers was coincident with the ambient wind direction, (2) increased with increasing tipspeed ratio, and (3) is due more to induced flow angularities downstream than to speed deficits near the downstream turbine.

  7. Advanced Wind Turbine Drivetrain Concepts. Workshop Report

    SciTech Connect

    none,

    2010-12-01

    This report presents key findings from the Department of Energy’s Advanced Drivetrain Workshop, held on June 29-30, 2010, to assess different advanced drivetrain technologies, their relative potential to improve the state-of-the-art in wind turbine drivetrains, and the scope of research and development needed for their commercialization in wind turbine applications.

  8. Blade feathering system for wind turbines

    SciTech Connect

    Harner, K.I.; Patrick, J.P.; Vosseller, K.F.

    1984-07-31

    A blade feathering system for wind turbines includes a feather actuator, control means operatively connected thereto and an adjustment means operatively connected to the control means for selectively varying the rate of operation of the feather actuator for feathering the wind turbine blades at a variable rate.

  9. Lightning protection system for a wind turbine

    SciTech Connect

    Costin, Daniel P.; Petter, Jeffrey K.

    2008-05-27

    In a wind turbine (104, 500, 704) having a plurality of blades (132, 404, 516, 744) and a blade rotor hub (120, 712), a lightning protection system (100, 504, 700) for conducting lightning strikes to any one of the blades and the region surrounding the blade hub along a path around the blade hub and critical components of the wind turbine, such as the generator (112, 716), gearbox (708) and main turbine bearings (176, 724).

  10. Certification testing for small wind turbines

    SciTech Connect

    Corbus, D.; Link, H.; Butterfield, S.; Stork, C.; Newcomb, C.

    1999-10-20

    This paper describes the testing procedures for obtaining type certification for a small wind turbine. Southwest Windpower (SWWP) is seeking type certification from Underwriters Laboratory (UL) for the AIR 403 wind turbine. UL is the certification body and the National Renewable Energy Laboratory (NREL) is providing technical assistance including conducting the certification testing. This is the first small turbine to be certified in the US, therefore standards must be interpreted and test procedures developed.

  11. MOD-2 wind turbine farm stability study

    NASA Astrophysics Data System (ADS)

    Hinrichsen, E. N.

    1980-06-01

    The dynamics of single and multiple 2.5 ME, Boeing MOD-2 wind turbine generators (WTGs) connected to utility power systems were investigated. The analysis was based on digital simulation. Both time response and frequency response methods were used. The dynamics of this type of WTG are characterized by two torsional modes, a low frequency 'shaft' mode below 1 Hz and an 'electrical' mode at 3-5 Hz. High turbine inertia and low torsional stiffness between turbine and generator are inherent features. Turbine control is based on electrical power, not turbine speed as in conventional utility turbine generators. Multi-machine dynamics differ very little from single machine dynamics.

  12. MOD-2 wind turbine farm stability study

    NASA Technical Reports Server (NTRS)

    Hinrichsen, E. N.

    1980-01-01

    The dynamics of single and multiple 2.5 ME, Boeing MOD-2 wind turbine generators (WTGs) connected to utility power systems were investigated. The analysis was based on digital simulation. Both time response and frequency response methods were used. The dynamics of this type of WTG are characterized by two torsional modes, a low frequency 'shaft' mode below 1 Hz and an 'electrical' mode at 3-5 Hz. High turbine inertia and low torsional stiffness between turbine and generator are inherent features. Turbine control is based on electrical power, not turbine speed as in conventional utility turbine generators. Multi-machine dynamics differ very little from single machine dynamics.

  13. Responses of floating wind turbines to wind and wave excitation

    E-print Network

    Lee, Kwang Hyun

    2005-01-01

    The use of wind power has recently emerged as a promising alternative to conventional electricity generation. However, space requirements and public pressure to place unsightly wind turbines out of visual range make it ...

  14. A Stochastic DEVS Wind Turbine Component Model for Wind Farm Simulation

    E-print Network

    Ding, Yu

    A Stochastic DEVS Wind Turbine Component Model for Wind Farm Simulation Eduardo P´erez, Lewis, wind turbine, DEVS, STDEVS Abstract Wind farms use several wind turbines to generate electricity variations in wind speed and direction, wind turbines experience stochastic loading that of- ten lead

  15. 1Design limits and solutions for very large wind turbines Design limits and solutions for very large wind turbines

    E-print Network

    Leu, Tzong-Shyng "Jeremy"

    #12;#12;1Design limits and solutions for very large wind turbines UpWind Design limits and solutions for very large wind turbines A 20 MW turbine is feasible March 2011 Supported by: #12;March 20112 Photo:Nordex #12;3Design limits and solutions for very large wind turbines Contents 1. UpWind: Summary

  16. 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.

  17. Turbulence in vertical axis wind turbine canopies

    NASA Astrophysics Data System (ADS)

    Kinzel, Matthias; Araya, Daniel B.; Dabiri, John O.

    2015-11-01

    Experimental results from three different full scale arrays of vertical-axis wind turbines (VAWTs) under natural wind conditions are presented. The wind velocities throughout the turbine arrays are measured using a portable meteorological tower with seven, vertically staggered, three-component ultrasonic anemometers. The power output of each turbine is recorded simultaneously. The comparison between the horizontal and vertical energy transport for the different turbine array sizes shows the importance of vertical transport for large array configurations. Quadrant-hole analysis is employed to gain a better understanding of the vertical energy transport at the top of the VAWT arrays. The results show a striking similarity between the flows in the VAWT arrays and the adjustment region of canopies. Namely, an increase in ejections and sweeps and decrease in inward and outward interactions occur inside the turbine array. Ejections are the strongest contributor, which is in agreement with the literature on evolving and sparse canopy flows. The influence of the turbine array size on the power output of the downstream turbines is examined by comparing a streamwise row of four single turbines with square arrays of nine turbine pairs. The results suggest that a new boundary layer forms on top of the larger turbine arrays as the flow adjusts to the new roughness length. This increases the turbulent energy transport over the whole planform area of the turbine array. By contrast, for the four single turbines, the vertical energy transport due to turbulent fluctuations is only increased in the near wake of the turbines. These findings add to the knowledge of energy transport in turbine arrays and therefore the optimization of the turbine spacing in wind farms.

  18. Meteorological aspects of siting large wind turbines

    SciTech Connect

    Hiester, T.R.; Pennell, W.T.

    1981-01-01

    This report, which focuses on the meteorological aspects of siting large wind turbines (turbines with a rated output exceeding 100 kW), has four main goals. The first is to outline the elements of a siting strategy that will identify the most favorable wind energy sites in a region and that will provide sufficient wind data to make responsible economic evaluations of the site wind resource possible. The second is to critique and summarize siting techniques that were studied in the Department of Energy (DOE) Wind Energy Program. The third goal is to educate utility technical personnel, engineering consultants, and meteorological consultants (who may have not yet undertaken wind energy consulting) on meteorological phenomena relevant to wind turbine siting in order to enhance dialogues between these groups. The fourth goal is to minimize the chances of failure of early siting programs due to insufficient understanding of wind behavior.

  19. Wind turbine control system modeling capabilities

    SciTech Connect

    Pierce, K.; Fingersh, L.J.

    1998-04-01

    At the National Renewable Energy Laboratory`s (NREL`s) National Wind Technology Center the authors are continuing to make progress in their ability to model complete wind turbine systems. An ADAMS{reg_sign} model of the NREL variable speed test bed turbine was developed to determine whether wind turbine control systems could be simulated and to investigate other control strategies for this turbine. Model simulations are compared with data from the operating turbine using the current mode of operation. In general, the simulations show good agreement with test data. Having established confidence in their ability to model the physical machine, the authors evaluated two other control methods. The methods studied are a generalized predictive control method and a bias estimation method. Simulation results using these methods are compared to simulation results of the current mode of operation of the turbine.

  20. INFLOW AND THE FATIGUE OF THE LIST WIND TURBINE*

    E-print Network

    1 INFLOW AND THE FATIGUE OF THE LIST WIND TURBINE* Herbert J. Sutherland Wind Energy Technology response data to characterize the spectrum of loads on wind turbines. A heavily instrumented Micon 65/13M turbine with SERI 8m blades is being used as the primary test turbine for this test. This turbine

  1. Influence of refraction on wind turbine noise

    E-print Network

    Makarewicz, Rufin

    2013-01-01

    A semi-empirical method is applied to calculate the time-average sound level of wind turbine noise generation and propagation. Both are affected by wind shear refraction. Under upwind conditions the partially ensonified zone separates the fully ensonified zone (close to the turbine) and the shadow zone (far away from the turbine). Refraction is described in terms of the wind speed linear profile fitted to the power law profile. The rotating blades are treated as a two-dimensional circular source in the vertical plane. Inside the partially ensonified zone the effective A-weighted sound power decreases to zero when the receiver moves from the turbine toward the shadow zone. The presented results would be useful in practical applications to give a quick estimate of the effect of refraction on wind turbine noise.

  2. Numerical investigation of wind turbine and wind farm aerodynamics

    NASA Astrophysics Data System (ADS)

    Selvaraj, Suganthi

    A numerical method based on the solution of Reynolds Averaged Navier Stokes equations and actuator disk representation of turbine rotor is developed and implemented in the OpenFOAM software suite for aerodynamic analysis of horizontal axis wind turbines (HAWT). The method and the implementation are validated against the 1-D momentum theory, the blade element momentum theory and against experimental data. The model is used for analyzing aerodynamics of a novel dual rotor wind turbine concept and wind farms. Horizontal axis wind turbines suffer from aerodynamic inefficiencies in the blade root region (near the hub) due to several non-aerodynamic constraints (e.g., manufacturing, transportation, cost, etc.). A new dual-rotor wind turbine (DRWT) concept is proposed that aims at mitigating these losses. A DRWT is designed using an existing turbine rotor for the main rotor (Risoe turbine and NREL 5 MW turbine), while the secondary rotor is designed using a high lift to drag ratio airfoil (the DU 96 airfoil from TU Delft). The numerical aerodynamic analysis method developed as a part of this thesis is used to optimize the design. The new DRWT design gives an improvement of about 7% in aerodynamic efficiency over the single rotor turbine. Wind turbines are typically deployed in clusters called wind farms. HAWTs also suffer from aerodynamic losses in a wind farm due to interactions with wind turbine wakes. An interesting mesoscale meteorological phenomenon called "surface flow convergence" believed to be caused by wind turbine arrays is investigated using the numerical method developed here. This phenomenon is believed to be caused by the pressure gradient set up by wind turbines operating in close proximity in a farm. A conceptual/hypothetical wind farm simulation validates the hypothesis that a pressure gradient is setup in wind farms due to turbines and that it can cause flow veering of the order of 10 degrees. Simulations of a real wind farm (Story County) are also conducted which give qualitatively correct flow direction change, however quantitative agreement with data is only moderately acceptable.

  3. Meteorological Controls on Wind Turbine Wakes

    SciTech Connect

    Barthelmie, RJ; Hansen, KS; Pryor, SC

    2013-04-01

    The primary control on the magnitude of the power losses induced by wind turbine wakes in large wind farms is the hub-height wind speed via its link to the turbine thrust coefficient. Hence, at low to moderate wind speeds (between cut-in and rated turbine wind speeds) when the thrust coefficient is high, wake losses are proportionally larger and decrease to be virtually undetectable at wind speeds above rated wind speeds. Wind direction is also critical. Not only does it determine the effective spacing between turbines but also the wind speed distribution is primarily determined by synoptic forcing and typically has a predominant direction from which wind speeds tend to be higher (from southwest for much of the central United States and northern Europe). Two other interlinked variables, turbulence intensity (TI), and atmospheric stability also dictate wake losses. Quantifying, understanding, modeling, and predicting this complex and interdependent system is therefore critical to understanding and modeling wind farm power losses due to wakes, and to optimizing wind farm layout. This paper quantifies the impact of these variables on the power loss due to wakes using data from the large offshore wind farms located at Horns Rev and Nysted in Denmark.

  4. 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.

  5. CFD modeling of wind turbine wake in wind farms

    NASA Astrophysics Data System (ADS)

    Sun, Lijian

    Wind energy is one of the most common and preferred renewable energy sources. Accurate predictions of atmospheric boundary layer flow, wind turbine induced wakes and their interaction are essential to maximize wind power output and efficiently harness wind energy. In this dissertation, a computational fluid dynamics (CFD) flow model is developed utilizing a three dimensional weighted essentially non-oscillatory (WENO) high order Finite Volume Model system including Large Eddy Simulation (LES) and the Actuator Line Method (ALM). The developed model system is thus able to accurately capture and simulate wind turbine wakes and their interaction with the atmospheric boundary layer, thereby providing insight into the phenomenon of turbine wake interaction and its effect on the external aerodynamic loads on wind turbines. This enables the wind energy production to be maximized and also minimizes turbine fatigue loading in the evaluation of wind farm layouts. By using LES model to simulate the Atmospheric Boundary Layer flow rather than the Reynolds-Averaged Navier-Stokes (RANS) model, the error introduced by turbulence modeling is reduced. The Actuator Line Model, ALM, is used to model the rotor by replacing the rotor with radially distributed body forces. It is more accurate than the actuator disc method as it captures the influence of the blade tip vortices. It can focus on a larger portion of the wake without resolving the actual wind turbine blades' geometry, thereby reducing computational cost. It is suitable and a promising method for wind turbine wake simulation. Classic non-trivial turbulent benchmark cases are used to validate the high order LES algorithms. Simulation results are compared with available results whenever possible, with good agreement observed. Results for the atmospheric boundary layer under neutral conditions are presented. By using LES coupled with the Actuator Line model, simulation results are obtained for detailed wake flow features around single wind turbine as well as wind turbine arrays.

  6. Acoustic emission monitoring of wind turbine blades

    NASA Astrophysics Data System (ADS)

    Van Dam, Jeremy; Bond, Leonard J.

    2015-03-01

    Damage to wind turbine blades can, if left uncorrected, evolve into catastrophic failures resulting in high costs and significant losses for the operator. Detection of damage, especially in real time, has the potential to mitigate the losses associated with such catastrophic failure. To address this need various forms of online monitoring are being investigated, including acoustic emission detection. In this paper, pencil lead breaks are used as a standard reference source and tests are performed on unidirectional glass-fiber-reinforced-polymer plates. The mechanical pencil break is used to simulate an acoustic emission (AE) that generates elastic waves in the plate. Piezoelectric sensors and a data acquisition system are used to detect and record the signals. The expected dispersion curves generated for Lamb waves in plates are calculated, and the Gabor wavelet transform is used to provide dispersion curves based on experimental data. AE sources using an aluminum plate are used as a reference case for the experimental system and data processing validation. The analysis of the composite material provides information concerning the wave speed, modes, and attenuation of the waveform, which can be used to estimate maximum AE event - receiver separation, in a particular geometry and materials combination. The foundational data provided in this paper help to guide improvements in online structural health monitoring of wind turbine blades using acoustic emission.

  7. 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.

  8. Active load control techniques for wind turbines.

    SciTech Connect

    van Dam, C.P.; Berg, Dale E.; Johnson, Scott J.

    2008-07-01

    This report provides an overview on the current state of wind turbine control and introduces a number of active techniques that could be potentially used for control of wind turbine blades. The focus is on research regarding active flow control (AFC) as it applies to wind turbine performance and loads. The techniques and concepts described here are often described as 'smart structures' or 'smart rotor control'. This field is rapidly growing and there are numerous concepts currently being investigated around the world; some concepts already are focused on the wind energy industry and others are intended for use in other fields, but have the potential for wind turbine control. An AFC system can be broken into three categories: controls and sensors, actuators and devices, and the flow phenomena. This report focuses on the research involved with the actuators and devices and the generated flow phenomena caused by each device.

  9. Effect of precipitation on wind turbine performance

    NASA Technical Reports Server (NTRS)

    Corrigan, R. D.; Demiglio, R. D.

    1985-01-01

    The effects of precipitation on wind turbine power output was analyzed. The tests were conducted on the two bladed Mod-0 horizontal axis wind turbine with three different rotor configurations. Experimental data from these tests are presented which clearly indicate that the performance of the Mod-0 wind turbine is affected by rain. Light rainfall degraded performance by as much as 20 percent while heavy rainfall degraded performance by as much as 30 percent. Snow mixed with drizzle degraded performance by as much as 36 percent at low windspeeds. Also presented are the results of an analysis to predict the effect of rain on wind turbine performance. This analysis used a blade element/momentum code with modified airfoil characteristics to account for the effect of rain and predicted a loss in performance of 31 percent in high winds with moderate rainfall rates. These predicted results agreed well with experimental data.

  10. PowerJet Wind Turbine Project

    SciTech Connect

    Bartlett, Raymond J

    2008-11-30

    PROJECT OBJECTIVE The PowerJet wind turbine overcomes problems characteristic of the small wind turbines that are on the market today by providing reliable output at a wide range of wind speeds, durability, silent operation at all wind speeds, and bird-safe operation. Prime Energy�s objective for this project was to design and integrate a generator with an electrical controller and mechanical controls to maximize the generation of electricity by its wind turbine. The scope of this project was to design, construct and test a mechanical back plate to control rotational speed in high winds, and an electronic controller to maximize power output and to assist the base plate in controlling rotational speed in high winds. The test model will continue to operate beyond the time frame of the project, with the ultimate goal of manufacturing and marketing the PowerJet worldwide. Increased Understanding of Electronic & Mechanical Controls Integrated With Electricity Generator The PowerJet back plate begins to open as wind speed exceeds 13.5 mps. The pressure inside the turbine and the turbine rotational speed are held constant. Once the back plate has fully opened at approximately 29 mps, the controller begins pulsing back to the generator to limit the rotational speed of the turbine. At a wind speed in excess of 29 mps, the controller shorts the generator and brings the turbine to a complete stop. As the wind speed subsides, the controller releases the turbine and it resumes producing electricity. Data collection and instrumentation problems prevented identification of the exact speeds at which these events occur. However, the turbine, controller and generator survived winds in excess of 36 mps, confirming that the two over-speed controls accomplished their purpose. Technical Effectiveness & Economic Feasibility Maximum Electrical Output The output of electricity is maximized by the integration of an electronic controller and mechanical over-speed controls designed and tested during the course of this project. The output exceeds that of the PowerJet�s 3-bladed counterparts (see Appendix). Durability All components of the PowerJet turbine assembly�including the electronic and mechanical controls designed, manufactured and field tested during the course of this project�proved to be durable through severe weather conditions, with constant operation and no interruption in energy production. Low Cost Materials for the turbine, generator, tower, charge controllers and ancillary parts are available at reasonable prices. Fabrication of these parts is also readily available worldwide. The cost of assembling and installing the turbine is reduced because it has fewer parts and requires less labor to manufacture and assemble, making it competitively priced compared with turbines of similar output manufactured in the U.S. and Europe. The electronic controller is the unique part to be included in the turbine package. The controllers can be manufactured in reasonably-sized production runs to keep the cost below $250 each. The data logger and 24 sensors are for research only and will be unnecessary for the commercial product. Benefit To Public The PowerJet wind-electric system is designed for distributed wind generation in 3 and 4 class winds. This wind turbine meets DOE�s requirements for a quiet, durable, bird-safe turbine that eventually can be deployed as a grid-connected generator in urban and suburban settings. Results As described more fully below and illustrated in the Appendices, the goals and objectives outlined in 2060 SOPO were fully met. Electronic and mechanical controls were successfully designed, manufactured and integrated with the generator. The turbine, tower, controllers and generators operated without incident throughout the test period, surviving severe winter and summer weather conditions such as extreme temperatures, ice and sustained high winds. The electronic controls were contained in weather-proof electrical boxes and the elec

  11. Wind technology development: Large and small turbines

    NASA Astrophysics Data System (ADS)

    Thresher, R. W.; Hock, S. M.; Loose, R. R.; Goldman, P.

    1994-12-01

    Wind technology has developed rapidly over the last decade with the design and development of advanced systems with improved performance, higher reliability, and lower costs. During the past several years, substantial gains have been made in wind turbine designs, lowering costs to an average of $0.05/kWh while further technology development is expected to allow the cost to drop below $0.04/kWh by 2000. As a result, wind is expected to be one of the least expensive forms of new electric generation in the next century. This paper will present the technology developments for both utility-scale wind turbines and remote, small-village wind turbines that are currently available or in development. Technology innovations are being adapted for remote and stand-alone power applications with smaller wind turbines. Hybrid power systems using smaller 1 to 50 (kW) wind turbines are being developed for non-grid-connected electrical generation applications. These village power systems typically use wind energy, photovoltaics, battery storage, and conventional diesel generators to power remote communities. Smaller turbines are being explored for application as distributed generation sources on utility grids to supply power during periods of peak demand, avoiding costly upgrades in distribution equipment. New turbine designs now account for turbulence-induced loads, unsteady aerodynamic stall effects, and complex fatigue loads, making use of new technology developments such as advanced airfoils. The new airfoils increase the energy capture, improve the operating efficiency, and reduce the sensitivity of the airfoils to operation roughness. Electronic controls are allowing variable rotor speed operation; while aerodynamic control devices, such as ailerons and flaps, are used to modulate power or stop the rotor in high-speed conditions. These technology trends and future turbine configurations are being sponsored and explored by the U.S. Department of Energy's Wind Energy Program.

  12. 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.

  13. Wind Turbine Drivetrain Condition Monitoring - An Overview

    SciTech Connect

    Sheng, S; Veers, P.

    2011-10-01

    This paper provides an overview of wind turbine drivetrain condition monitoring based on presentations from a condition monitoring workshop organized by the National Renewable Energy Laboratory in 2009 and on additional references.

  14. Diffuser for augmenting a wind turbine

    DOEpatents

    Foreman, Kenneth M. (North Bellmore, NY); Gilbert, Barry L. (Westbury, NY)

    1984-01-01

    A diffuser for augmenting a wind turbine having means for energizing the boundary layer at several locations along the diffuser walls is improved by the addition of a short collar extending radially outward from the outlet of the diffuser.

  15. Flexible dynamics of floating wind turbines

    E-print Network

    Luypaert, Thomas (Thomas J.)

    2012-01-01

    This work presents Tower Flex, a structural dynamics model for a coupled analysis of offshore floating wind turbines consisting of a tower, a floating platform and a mooring system. In this multi-body, linear frequency-domain ...

  16. Vertical Axis Wind Turbine Foundation parameter study

    SciTech Connect

    Lodde, P.F.

    1980-07-01

    The dynamic failure criterion governing the dimensions of prototype Vertical Axis Wind Turbine Foundations is treated as a variable parameter. The resulting change in foundation dimensions and costs is examined.

  17. Wind Turbine Safety and Function Test Report for the Mariah Windspire Wind Turbine

    SciTech Connect

    Huskey, A.; Bowen, A.; Jager, D.

    2010-07-01

    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 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 certification 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.

  18. Utility scale application of wind turbines

    NASA Astrophysics Data System (ADS)

    Belt, R. M.

    The development of wind turbines for utility interconnection, problems inherent in utility scale application of wind-derived power, and specific features of interconnection with the Hawaiian electric system are discussed. Modern wind turbine generators are being developed to withstand sudden wind gusts, maintain generation stability, and tolerate external electrical faults. Utility integration of wind power is constrained by necessities of using optimized generator mixes. The total proportion of wind derived power that a grid may tolerate is as yet unknown, and is dependent on the generator control system response rates, noting that conventional ramping rates are in the range 1-5%. Control rates are bounded by maximum and minimum generation rates on spinning generators. Methods of determining on-site wind patterns using anemometry and electronically stored data are reviewed. Studies to determine the effects of frequent fluctuations on consumer equipment, and to adequately model the introduction of integrated wind farm-grid systems are indicated.

  19. Passively cooled direct drive wind turbine

    SciTech Connect

    Costin, Daniel P.

    2008-03-18

    A wind turbine is provided that passively cools an electrical generator. The wind turbine includes a plurality of fins arranged peripherally around a generator house. Each of the fins being oriented at an angle greater than zero degrees to allow parallel flow of air over the fin. The fin is further tapered to allow a constant portion of the fin to extend beyond the air stream boundary layer. Turbulence initiators on the nose cone further enhance heat transfer at the fins.

  20. Wind Turbine Safety and Function Test Report for the Gaia-Wind 11-kW Wind Turbine

    SciTech Connect

    Huskey, A.; Bowen, A.; Jager, D.

    2010-01-01

    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 to wind energy expansion by providing independent testing results for small wind turbines (SWT). In total, four 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. The results of the testing provide the manufacturers with reports that can be used for small wind turbine certification. The test equipment includes a Gaia-Wind 11-kW wind turbine mounted on an 18-m monopole tower. Gaia-Wind Ltd. manufactured the turbine in Denmark. The system was installed by the NWTC site operations group with guidance and assistance from Gaia-Wind.

  1. 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.

  2. 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. PMID:25267628

  3. 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

  4. Jet spoiler arrangement for wind turbine

    DOEpatents

    Cyrus, Jack D. (Corrales, NM); Kadlec, Emil G. (Albuquerque, NM); Klimas, Paul C. (Albuquerque, NM)

    1985-01-01

    An air jet spoiler arrangement is provided for a Darrieus-type vertical axis wind-powered turbine. Air is drawn into hollow turbine blades through air inlets at the ends thereof and is ejected in the form of air jets through small holes or openings provided along the lengths of the blades. The air jets create flow separation at the surfaces of the turbine blades, thereby inducing stall conditions and reducing the output power. A feedback control unit senses the power output of the turbine and controls the amount of air drawn into the air inlets accordingly.

  5. Jet spoiler arrangement for wind turbine

    DOEpatents

    Cyrus, J.D.; Kadlec, E.G.; Klimas, P.C.

    1983-09-15

    An air jet spoiler arrangement is provided for a Darrieus-type vertical axis wind-powered turbine. Air is drawn into hollow turbine blades through air inlets at the end thereof and is ejected in the form of air jets through small holes or openings provided along the lengths of the blades. The air jets create flow separation at the surfaces of the turbine blades, thereby including stall conditions and reducing the output power. A feedback control unit senses the power output of the turbine and controls the amount of air drawn into the air inlets accordingly.

  6. 2/16/2014 Can You Charge Your Mobile With Wind Turbine? -TechTxr http://www.techtxr.com/can-charge-mobile-wind-turbine/ 1/7

    E-print Network

    Chiao, Jung-Chih

    2/16/2014 Can You Charge Your Mobile With Wind Turbine? - TechTxr http://www.techtxr.com/can-charge-mobile-wind-turbine Turbine? | February 9, 2014 Wind Energy Wind Mill Wind Power Wind Mobile About Wind Power Wind Generator Mobile Generator Mobile Building #12;2/16/2014 Can You Charge Your Mobile With Wind Turbine

  7. Local blockage effect for wind turbines

    NASA Astrophysics Data System (ADS)

    Nishino, Takafumi; Draper, Scott

    2015-06-01

    This paper presents a combined theoretical and CFD study on the fluid-mechanical limit of power extraction by a closely-spaced lateral array of wind turbines. The idea of this study originates in recent studies on the array optimisation of tidal/marine turbines, for which the power coefficient of each turbine is known to increase significantly if the lateral spacing between turbines, or the local blockage, is optimised. The present study, using 3D Reynolds- averaged Navier-Stokes (RANS) simulations of a boundary-layer flow over a closely-spaced lateral array of up to 9 actuator discs, suggests that a similar—albeit less significant—power increase due to the effect of local blockage can be achieved even for wind turbines. A possible theoretical approach to estimating this power increase is also discussed.

  8. Infrasound emission generated by wind turbines

    NASA Astrophysics Data System (ADS)

    Ceranna, Lars; Pilger, Christoph

    2014-05-01

    Aerodynamic noise emissions from the continuously growing number of wind turbines in Germany are creating increasing problems for infrasound recording systems. Such systems are equipped with highly sensitive micro pressure sensors, which are accurately measuring acoustic signals in a frequency range inaudible to humans. At infrasound station IGADE, north of Bremen, a constantly increasing background noise has been observed throughout the years since its installation in 2005. The spectral peaks are reflecting well the blade passing harmonics, which vary with prevailing wind speeds. Overall, a decrease is noted for the infrasound array's detection capability. This aspect is particularly important for the other two sites of the German infrasound stations I26DE in the Bavarian Forest and I27DE in Antarctica, because plans for installing wind turbines near these locations are being under discussion. These stations are part of the International Monitoring System (IMS) verifying compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT), and have to meet stringent specifications with respect to infrasonic background noise. Therefore data obtained during a field experiment with mobile micro-barometer stations for measuring the infrasonic pressure level of a single horizontal-axis wind turbine have been revisited. The results of this experiment successfully validate a theoretical model which estimates the generated sound pressure level of wind turbines and makes it possible to specify the minimum allowable distance between wind turbines and infrasound stations for undisturbed recording. Since the theoretical model also takes wind turbine design parameters into account, suitable locations for planned infrasound stations outside the determined disturbance range can be found, which will be presented; and vice versa, the model calculations' results for fixing the minimum distance for wind turbines planned for installation in the vicinity of an existing infrasound array.

  9. Vertical axis wind turbine control strategy

    SciTech Connect

    McNerney, G.M.

    1981-08-01

    Early expensive in automatic operation of the Sandia 17-m vertical axis research wind turbine (VAWT) has demonstrated the need for a systematic study of control algorithms. To this end, a computer model has been developed that uses actual wind time series and turbine performance data to calculate the power produced by the Sandia 17-m VAWT operating in automatic control. The model has been used to investigate the influence of starting algorithms on annual energy production. The results indicate that, depending on turbine and local wind characteristics, a bad choice of a control algorithm can significantly reduce overall energy production. The model can be used to select control algorithms and threshold parameters that maximize long-term energy production. An attempt has been made to generalize these results from local site and turbine characteristics to obtain general guidelines for control algorithm design.

  10. Field verification program for small wind turbines

    SciTech Connect

    Windward Engineering, LLC

    2003-11-30

    In 1999 Windward Engineering (Windward) was awarded a Cooperative Agreement under the Field Verification Program with the Department of Energy (DOE) to install two Whisper H40 wind turbines, one at the NREL National Wind Technology Center (NWTC) and one at a test site near Spanish Fork, Utah. After installation, the turbine at the NWTC was to be operated, maintained, and monitored by NREL while the turbine in Spanish Fork was to be administered by Windward. Under this award DOE and Windward defined the primary objectives of the project as follows: (1) Determine and demonstrate the reliability and energy production of a furling wind turbine at a site where furling will be a very frequent event and extreme gusts can be expected during the duration of the tests. (2) Make engineering measurements and conduct limited computer modeling of the furling behavior to improve the industry understanding of the mechanics and nature of furling. We believe the project has achieved these objectives. The turbine has operated for approximately three and a half years. We have collected detailed engineering data approximately 75 percent of that time. Some of these data were used in an ADAMS model validation that highlighted the accuracies and inaccuracies of the computer modeling for a passively furling wind turbine. We also presented three papers at the American Wind Energy Association (AWEA) Windpower conferences in 2001, 2002, and 2003. These papers addressed the following three topics: (a) general overview of the project [1], (b) furling operation during extreme wind events [2], and (c) extrapolation of extreme (design) loads [3]. We believe these papers have given new insight into the mechanics and nature of furling and have set the stage for future research. In this final report we will highlight some of the more interesting aspects of the project as well as summarize the data for the entire project. We will also present information on the installation of the turbines as well as the findings from the post-test inspection of the turbine.

  11. Large Horizontal-Axis Wind Turbines

    NASA Technical Reports Server (NTRS)

    Thresher, R. W. (editor)

    1982-01-01

    The proceedings of a workshop held in Cleveland, July 28-30, 1981 are described. The workshop emphasized recent experience in building and testing large propeller-type wind turbines, expanding upon the proceedings of three previous DOE/NASA workshops at which design and analysis topics were considered. A total of 41 papers were presented on the following subjects: current and advanced large wind turbine systems, rotor blade design and manufacture, electric utility activities, research and supporting technology, meteorological characteristics for design and operation, and wind resources assessments for siting.

  12. Large horizontal axis wind turbine development

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    An overview of the NASA activities concerning ongoing wind systems oriented toward utility application is presented. First-generation-technology large wind turbines were designed and are in operation at selected utility sites. In order to make a significant energy impact, costs of 2 to 3 cents per kilowatt hour must be achieved. The federal program continues to fund the development by industry of wind turbines which can meet the cost goals of 2 to 3 cents per kilowatt hour. Lower costs are achieved through the incorporation of new technology and innovative system design to reduce weight and increase energy capture.

  13. Broad band sound from wind turbine generators

    NASA Technical Reports Server (NTRS)

    Hubbard, H. H.; Shepherd, K. P.; Grosveld, F. W.

    1981-01-01

    Brief descriptions are given of the various types of large wind turbines and their sound characteristics. Candidate sources of broadband sound are identified and are rank ordered for a large upwind configuration wind turbine generator for which data are available. The rotor is noted to be the main source of broadband sound which arises from inflow turbulence and from the interactions of the turbulent boundary layer on the blade with its trailing edge. Sound is radiated about equally in all directions but the refraction effects of the wind produce an elongated contour pattern in the downwind direction.

  14. Variable diameter wind turbine rotor blades

    DOEpatents

    Jamieson, Peter McKeich; Hornzee-Jones, Chris; Moroz, Emilian M.; Blakemore, Ralph W.

    2005-12-06

    A system and method for changing wind turbine rotor diameters to meet changing wind speeds and control system loads is disclosed. The rotor blades on the wind turbine are able to adjust length by extensions nested within or containing the base blade. The blades can have more than one extension in a variety of configurations. A cable winching system, a hydraulic system, a pneumatic system, inflatable or elastic extensions, and a spring-loaded jack knife deployment are some of the methods of adjustment. The extension is also protected from lightning by a grounding system.

  15. Wind Turbines and Health A Rapid Review of the Evidence

    E-print Network

    Firestone, Jeremy

    1 Wind Turbines and Health A Rapid Review of the Evidence July 2010 #12;2 Wind Turbines and Health of the evidence from current literature on the issue of wind turbines and potential impacts on human health: There are no direct pathological effects from wind farms and that any potential impact on humans can be minimised

  16. TECHNICALADVANCES IN EPOXY TECHNOLOGY FOR WIND TURBINE BLADE COMPOSITE FABRICATION

    E-print Network

    TECHNICALADVANCES IN EPOXY TECHNOLOGY FOR WIND TURBINE BLADE COMPOSITE FABRICATION George C. Jacob reliability in many demanding applications including components for aerospace and wind turbine blades. While in operation, wind turbine blades are subjected to significant stresses from their movement, wind and other

  17. Nonlinear Control of a Wind Turbine Sven Creutz Thomsen

    E-print Network

    Nonlinear Control of a Wind Turbine Sven Creutz Thomsen Kongens Lyngby 2006 #12; Technical describes analysis of various nonlinear control methods for controlling a wind turbine. High speed wind Modeling and analysis 5 2 Model descriptions 7 2.1 Variable speed wind turbine

  18. Nonlinear Control of a Wind Turbine Sven Creutz Thomsen

    E-print Network

    Nonlinear Control of a Wind Turbine Sven Creutz Thomsen Kongens Lyngby 2006 #12;Technical describes analysis of various nonlinear control methods for controlling a wind turbine. High speed wind descriptions 7 2.1 Variable speed wind turbine . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2 Constant

  19. Load attenuating passively adaptive wind turbine blade

    DOEpatents

    Veers, Paul S. (Albuquerque, NM); Lobitz, Donald W. (Albuquerque, NM)

    2003-01-01

    A method and apparatus for improving wind turbine performance by alleviating loads and controlling the rotor. The invention employs the use of a passively adaptive blade that senses the wind velocity or rotational speed, and accordingly modifies its aerodynamic configuration. The invention exploits the load mitigation prospects of a blade that twists toward feather as it bends. The invention includes passively adaptive wind turbine rotors or blades with currently preferred power control features. The apparatus is a composite fiber horizontal axis wind-turbine blade, in which a substantial majority of fibers in the blade skin are inclined at angles of between 15 and 30 degrees to the axis of the blade, to produces passive adaptive aeroelastic tailoring (bend-twist coupling) to alleviate loading without unduly jeopardizing performance.

  20. Load attenuating passively adaptive wind turbine blade

    DOEpatents

    Veers, Paul S.; Lobitz, Donald W.

    2003-01-07

    A method and apparatus for improving wind turbine performance by alleviating loads and controlling the rotor. The invention employs the use of a passively adaptive blade that senses the wind velocity or rotational speed, and accordingly modifies its aerodynamic configuration. The invention exploits the load mitigation prospects of a blade that twists toward feather as it bends. The invention includes passively adaptive wind turbine rotors or blades with currently preferred power control features. The apparatus is a composite fiber horizontal axis wind-turbine blade, in which a substantial majority of fibers in the blade skin are inclined at angles of between 15 and 30 degrees to the axis of the blade, to produces passive adaptive aeroelastic tailoring (bend-twist coupling) to alleviate loading without unduly jeopardizing performance.

  1. Wind Turbine Micropitting Workshop: A Recap

    SciTech Connect

    Sheng, S.

    2010-02-01

    Micropitting is a Hertzian fatigue phenomenon that affects many wind turbine gearboxes, and it affects the reliability of the machines. With the major growth and increasing dependency on renewable energy, mechanical reliability is an extremely important issue. The U.S. Department of Energy has made a commitment to improving wind turbine reliability and the National Renewable Energy Laboratory (NREL) has started a gearbox reliability project. Micropitting as an issue that needed attention came to light through this effort. To understand the background of work that had already been accomplished, and to consolidate some level of collective understanding of the issue by acknowledged experts, NREL hosted a wind turbine micropitting workshop, which was held at the National Wind Technology Center in Boulder, Colorado, on April 15 and 16, 2009.

  2. Active robust control of wind turbines

    NASA Astrophysics Data System (ADS)

    Rezaei, Vahid

    The research work conducted in this thesis focuses on robustness of wind energy conversion system with respect to faults in pitch actuator in order to prevent unnecessary emergency shutdown, and keep the turbine operational without significant inefficiency in its overall performance. The objective is to investigate the feasibility of using a fault estimator and a light detection and ranging (LIDAR) system as additional sensors to design a suitable control system for wind turbines. Robust control technique is used to address these issues. Three controllers are proposed in this work that try to address sources of inaccuracy in wind turbine operation: An active fault tolerant controller is first designed using a fault estimator. It is shown that a set of locally robust controllers with respect to the fault, together with a suitable smooth mixing approach, manages to overcome the problem of faults in the pitch actuator. To address the wind-dependent behavior of turbines, a second controller is designed using the LIDAR sensor. In this configuration, LIDAR provides the look ahead wind information and generates a smooth scheduling signal to provide active robustness with respect to the changes in wind speed. Lastly, utilizing both the fault estimator and LIDAR, a 2-dimensional wind-dependent active fault tolerant controller is developed to control the wind turbine in region 3 of operation. The feasibility of the proposed ideas is verified in simulation. For this purpose, the US National Renewable Energy Laboratory's FAST code is used to model the 3-balded controls advanced research turbine. A discussion on practical considerations and ideas for future work are also presented.

  3. 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.

  4. Wind Turbine Safety and Function Test Report for the ARE 442 Wind Turbine

    SciTech Connect

    van Dam, J.; Baker, D.; Jager, D.

    2010-02-01

    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. In total, four 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 that were performed on the turbines, including power performance, duration, noise, and power quality tests. Test results provide manufacturers with reports that can be used for small wind turbine certification. The test equipment includes an ARE 442 wind turbine mounted on a 100-ft free-standing lattice tower. The system was installed by the NWTC Site Operations group with guidance and assistance from Abundant Renewable Energy.

  5. Mars Technologies Spawn Durable Wind Turbines

    NASA Technical Reports Server (NTRS)

    2014-01-01

    To develop and test wind power technology for use on Mars, Ames Research Center turned to Northern Power Systems (NPS), based in Barre, Vermont. Ames awarded NPS an SBIR contract so the company could enhance their turbine’s function. Today, over 200 NASA-derived Northern Power 100s are in operation on Earth and have reduced carbon emissions by 50,000 tons annually.

  6. Use of three-winding step-up transformer in the cogeneration power plant from technical and economical consideration

    SciTech Connect

    Kuo, C.K.; Zavadivker, P.

    1995-10-01

    Using two individual generator step-up transformers for a gas turbine generator and a steam turbine generator in a cogeneration power plant is a common practice and offers good control during operations. A single three-winding transformer with two low side windings, one for the gas turbine generator and another for the steam turbine generator, is a feasible option to replace two transformers. The advantage of the three-winding transformer is economy. The price of the three-winding transformer is considerably lower than the sum price of two two-winding transformers and their associated high voltage switchyard interfaces. A savings of 20 percent or more in the transformer cost is possible. Space savings is another advantage. In a three-winding transformer, however, some technical challenges are encountered. Namely, the potential for overheating in a secondary winding, if it is under a no-load condition when the other secondary winding is fully loaded.

  7. The NASA Lewis large wind turbine program

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    The program is directed toward 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 generation systems. In addition, these large wind turbines must be fully compatible with electric utility operations and interface requirements. Advances are made by gaining a better understanding of the system design drivers, improvements in the analytical design tools, verification of design methods with operating field data, and the incorporation of new technology and innovative designs. An overview of the program activities is presented and includes results from the first and second generation field machines (Mod-OA, -1, and -2), the design phase of the third generation wind turbine (Mod-5) and the advanced technology projects. Also included is the status of the Department of Interior WTS-4 machine.

  8. Methods of making wind turbine rotor blades

    DOEpatents

    Livingston, Jamie T. (Pensacola, FL); Burke, Arthur H. E. (Gulf Breeze, FL); Bakhuis, Jan Willem (Nijverdal, NL); Van Breugel, Sjef (Enschede, NL); Billen, Andrew (Daarlerveen, NL)

    2008-04-01

    A method of manufacturing a root portion of a wind turbine blade includes, in an exemplary embodiment, providing an outer layer of reinforcing fibers including at least two woven mats of reinforcing fibers, providing an inner layer of reinforcing fibers including at least two woven mats of reinforcing fibers, and positioning at least two bands of reinforcing fibers between the inner and outer layers, with each band of reinforcing fibers including at least two woven mats of reinforcing fibers. The method further includes positioning a mat of randomly arranged reinforcing fibers between each pair of adjacent bands of reinforcing fibers, introducing a polymeric resin into the root potion of the wind turbine blade, infusing the resin through the outer layer, the inner layer, each band of reinforcing fibers, and each mat of random reinforcing fibers, and curing the resin to form the root portion of the wind turbine blade.

  9. Multi-hazard Reliability Assessment of Offshore Wind Turbines 

    E-print Network

    Mardfekri Rastehkenari, Maryam 1981-

    2012-12-04

    A probabilistic framework is developed to assess the structural reliability of offshore wind turbines. Probabilistic models are developed to predict the deformation, shear force and bending moment demands on the support structure of wind turbines...

  10. A doubly-fed permanent magnet generator for wind turbines

    E-print Network

    Thomas, Andrew J. (Andrew Joseph), 1981-

    2004-01-01

    Optimum extraction of energy from a wind turbine requires that turbine speed vary with wind speed. Existing solutions to produce constant-frequency electrical output under windspeed variations are undesirable due to ...

  11. Wind tunnel tests of a free yawing downwind wind turbine

    NASA Astrophysics Data System (ADS)

    Verelst, D. R. S.; Larsen, T. J.; van Wingerden, J. W.

    2014-12-01

    This research paper presents preliminary results on a behavioural study of a free yawing downwind wind turbine. A series of wind tunnel tests was performed at the TU Delft Open Jet Facility with a three bladed downwind wind turbine and a rotor radius of 0.8 meters. The setup includes an off the shelf three bladed hub, nacelle and generator on which relatively flexible blades are mounted. The tower support structure has free yawing capabilities provided at the base. A short overview on the technical details of the experiment is given as well as a brief summary of the design process. The discussed test cases show that the turbine is stable while operating in free yawing conditions. Further, the effect of the tower shadow passage on the blade flapwise strain measurement is evaluated. Finally, data from the experiment is compared with preliminary simulations using DTU Wind Energy's aeroelastic simulation program HAWC2.

  12. Innovative system for wind turbine testing

    SciTech Connect

    Camporeale, S.M.; Fortunato, B.; Marilli, G.

    1998-07-01

    An innovative system for testing small wind turbine models, is presented. The system is especially designed for Darrieus type turbines. The turbine is directly coupled to a direct current machine and a chopper, electronically controlled by means of a Pulse Width Modulator, is used to supply the circuit. The system is used for driving the turbine during the start-up procedure and for braking at various speeds during the performance test. In the paper the main characteristics of the electronic system are described and compared with a traditional system. The main goal of the electronic control is to increase the accuracy in the measurements of torque and speed for each steady state point of the turbine characteristic curve. Another useful advantage provided by the electronic control is related to the possibility of fine tuning the load in order to obtain a large number of steady state experimental points describing the characteristic curve of the turbine. Moreover the system is suitable for integration in an automatic data acquisition and control system. The experimental results, obtained in testing a small turbine in a wind tunnel by means of the electronic control system are presented and discussed at the end of the paper.

  13. 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.

  14. Fatigue and Reliability of Wind Turbines

    Energy Science and Technology Software Center (ESTSC)

    1995-08-17

    FAROW is a computer program that assists in the probalistic analysis of the Fatigue and Reliabiity of Wind turbines. The fatigue lifetime of wind turbine components is calculated using functional forms for important input quantities. Parameters of these functions are defined in an input file as either constants or random variables. The user can select from a library of random variable distribution functions. FAROW uses structural reliability techniques to calculate the mean time to failure,more »probability of failure before a target lifetime, relative importance of each of the random inputs, and the sensitivity of the reliability to all input parameters. Monte Carlo simulation is also available.« less

  15. Wind turbine blade aerodynamics: The combined experiment

    SciTech Connect

    Robinson, M.C.; Luttges, M.W.; Miller, M.S.; Shipley, D.E.; Young, T.S.

    1994-08-01

    Data obtained from the National Renewable Energy Laboratory site test of a wind turbine (The Combined Experiment) was analyzed specifically to capture information regarding the aerodynamic loading experienced by such machines. The analysis showed that inflow conditions were extremely variable and that these inflows yielded three different operational regimes. Each regime produces very different aerodynamic loading conditions that must be tolerated by the turbine. The two conditions not predicted from wind tunnel data are being subjected to further analyses to provide new guidelines for both designers and operators.

  16. Aileron controls for wind turbine applications

    NASA Technical Reports Server (NTRS)

    Miller, D. R.; Putoff, R. L.

    1984-01-01

    Horizontal axis wind turbines which utilize partial or full variable blade pitch to regulate rotor speed were examined. The weight and costs of these systems indicated a need for alternate methods of rotor control. Aileron control is an alternative which has potential to meet this need. Aileron control rotors were tested on the Mod-O wind turbine to determine their power regulation and shutdown characteristics. Test results for a 20 and 38% chord aileron control rotor are presented. Test is shown that aileron control is a viable method for safety for safely controlling rotor speed, following a loss of general load.

  17. Experimental wind tunnel testing of linear individual pitch control for two-bladed wind turbines

    NASA Astrophysics Data System (ADS)

    van Solingen, Edwin; Navalkar, Sachin; van Wingerden, Jan-Willem

    2014-06-01

    In this paper Linear Individual Pitch Control (LIPC) is applied to an experimental small-scale two-bladed wind turbine. LIPC is a recently introduced Individual Pitch Control (IPC) strategy specifically intended for two-bladed wind turbines. The LIPC approach is based on a linear coordinate transformation, with the special property that only two control loops are required to potentially reduce all periodic blade loads. In this study we apply LIPC to a control-oriented small-scale two-bladed wind turbine, equipped with, among others, two high- bandwidth servomotors to regulate the blade pitch angles and strain gauges to measure the blade moments. Experimental results are presented that indicate the effectiveness of LIPC.

  18. Structural responses and power output of a wind turbine are strongly affected by the wind field acting on the wind turbine. Knowledge about the wind field and its

    E-print Network

    Stanford University

    ABSTRACT Structural responses and power output of a wind turbine are strongly affected by the wind affect the power output and structural responses of a wind turbine. Wind field characteristics are conventionally described by time averaged features, such as mean wind speed, turbulence intensity and power

  19. Amplitude modulation of wind turbine noise

    E-print Network

    Makarewicz, Rufin

    2013-01-01

    Due to swish and thump amplitude modulation, the noise of wind turbines cause more annoyance than other environmental noise of the same average level. The wind shear accounts for the thump modulation (van den Berg effect). Making use of the wind speed measurements at the hub height, as well as at the top and the bottom of the rotor disc (Fig.1), the non-standard wind profile is applied. It causes variations in the A-weighted sound pressure level, LpA. The difference between the maximum and minimum of LpA characterizes thump modulation (Fig.2).

  20. 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.

  1. Control of Wind Turbines for Power Regulation and

    E-print Network

    Control of Wind Turbines for Power Regulation and Load Reduction Juan Jose Garcia Quirante Kongens regulation and load reduction and their ensemble in a variable-speed wind turbine. The power regulation aspects of mathematical modelling of wind turbines, and especially the control methods suited for power

  2. Experiments with a diffuser augmented model wind turbine

    SciTech Connect

    Gilbert, B.L.; Foreman, K.M.

    1982-03-01

    The initial stages of the experimental development of the diffuser augmented wind turbine (DAWT) employed various screen meshes to simulate the energy extraction mechanisms of a wind turbine. In this investigation in a 2 x 3 m (and x 10 ft) wind tunnel, a three bladed constant chord, untwisted turbine model was incorporated into a DAWT model. 8 refs.

  3. Decades of Wind Turbine Load Simulation Matthew Barone

    E-print Network

    Decades of Wind Turbine Load Simulation Matthew Barone , Joshua Paquette , Brian Resor Sandia-performance computer was used to simulate ninety-six years of operation of a five megawatt wind turbine. Over five million aero-elastic simulations were performed, with each simulation consisting of wind turbine operation

  4. IMPLEMENTATION OF WIND TURBINE CONTROLLERS W.E.Leithead

    E-print Network

    Duffy, Ken

    IMPLEMENTATION OF WIND TURBINE CONTROLLERS D.J.Leith W.E.Leithead Department of Electronic-speed wind turbines are considered, namely, (1) accommodation of the strongly nonlinear rotor aerodynamics derived and extended to cater for all wind turbine configurations. A rigorous stability analysis

  5. Stochastic Analysis of Wind Turbine Power Curves Edgar Anahua

    E-print Network

    Peinke, Joachim

    Stochastic Analysis of Wind Turbine Power Curves Edgar Anahua Oldenburg 2007 Zur Homepage der Dissertation #12;#12;Stochastic Analysis of Wind Turbine Power Curves Edgar Anahua Von der Fakult¨at f the wind turbine's power per- formance directly from high frequency fluctuating measurements. In particular

  6. EFFECTS OF FIBER WAVINESS ON COMPOSITES FOR WIND TURBINE BLADES

    E-print Network

    EFFECTS OF FIBER WAVINESS ON COMPOSITES FOR WIND TURBINE BLADES J.F. Mandell D.D. Samborsky and L Composite materials of interest for wind turbine blades use relatively low cost fibers, resins and processes WORDS: Composite Materials, Fiber Waviness, Compressive Strength #12;1. INTRODUCTION Wind turbine blades

  7. ACOUSTIC STUDY OF THE UD / GAMESA WIND TURBINE PROJECT

    E-print Network

    Firestone, Jeremy

    ACOUSTIC STUDY OF THE UD / GAMESA WIND TURBINE PROJECT LEWES, DELAWARE January 2009 #12;ACOUSTIC STUDY OF THE UNIVERSITY OF DELAWARE / GAMESA WIND TURBINE PROJECT LEWES, DELAWARE Prepared for SUMMARY The University of Delaware (UD), Lewes proposes to locate a Gamesa G90 2.0MW wind turbine

  8. In Conjunction with Applied Mathematics Institute Wind Turbine Aerodynamics: Some

    E-print Network

    Yu, Xinwei

    In Conjunction with Applied Mathematics Institute Wind Turbine Aerodynamics: Some history and some to aerodynamics in general, and wind turbine aerodynamics in particular. He was entirely responsible the Betz limit for wind turbine power before Betz published it in 1920, and was instrumental in developing

  9. SOUND COMPLIANCE MONITORING FOR THE GAMESA WIND TURBINE

    E-print Network

    Firestone, Jeremy

    SOUND COMPLIANCE MONITORING FOR THE GAMESA WIND TURBINE UD - LEWES, DELAWARE January 2011 ` #12;SOUND COMPLIANCE MONITORING FOR THE GAMESA WIND TURBINE AT THE UNIVERSITY OF DELAWARE LEWES, DELAWARE A Gamesa G90 2.0-MW wind turbine operates at the University of Delaware (UD), Lewes campus on a parcel

  10. Duration Test Report for the Entegrity EW50 Wind Turbine

    SciTech Connect

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

    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.

  11. CRAEATED ON JUNE 5, 2014 Wind Turbine Control Systems Analysis

    E-print Network

    Lavaei, Javad

    CRAEATED ON JUNE 5, 2014 Wind Turbine Control Systems Analysis ­ Introduction to PID Controller power was converted into electrical energy. Large wind turbines are used to convert kinetic energy turbine design to minimize deviation of the rotor speed at variable wind speed. The proportional

  12. Flutter Speed Predictions for MW-Sized Wind Turbine Blades

    E-print Network

    Flutter Speed Predictions for MW-Sized Wind Turbine Blades Don W. Lobitz Sandia National instability historically has not been a driving issue in wind turbine design. In fact, rarely has this issue even been addressed in the past. Commensurately, of the wind turbines that have been built, rarely has

  13. AIAA-2001-0044 Extreme Load Estimation for Wind Turbines

    E-print Network

    AIAA-2001-0044 Extreme Load Estimation for Wind Turbines: Issues and Opportunities for Improved design load estimation procedures for wind turbines often do not accurately treat the statistical nature of loads. Current practice for wind turbine load analysis is reviewed. The authors

  14. AIAA-2001-0047 PARAMETRIC MODELS FOR ESTIMATING WIND TURBINE

    E-print Network

    Sweetman, Bert

    AIAA-2001-0047 1 PARAMETRIC MODELS FOR ESTIMATING WIND TURBINE FATIGUE LOADS FOR DESIGN Lance 94305-4020 ABSTRACT International standards for wind turbine certification depend on finding long. INTRODUCTION Design constraints for wind turbine structures fall into either extreme load or fatigue categories

  15. AIAA980057 RELATING TURBULENCE TO WIND TURBINE BLADE LOADS

    E-print Network

    Sweetman, Bert

    AIAA­98­0057 RELATING TURBULENCE TO WIND TURBINE BLADE LOADS: PARAMETRIC STUDY WITH MULTIPLE that is most useful in estimating fatigue loads on wind turbine blades. The histograms of rainflow counted for flapwise loads on three horizontal axis wind tur­ bines(HAWTs). In the case of two of these turbines

  16. AIAA-2004-1184 AN AEROACOUSTIC ANALYSIS OF WIND TURBINES*

    E-print Network

    AIAA-2004-1184 1 AN AEROACOUSTIC ANALYSIS OF WIND TURBINES* Philip J. Morris, Lyle N. Long computational aeroacoustic methods that are being applied to predict the noise radiated by wind turbines. Since the wind turbine noise problem is very challenging, only some of the important noise sources and mechanisms

  17. Design Loads for Wind Turbines using the Environmental Contour Method

    E-print Network

    Manuel, Lance

    Design Loads for Wind Turbines using the Environmental Contour Method Korn Saranyasoontorn, TX 78712 When interest is in establishing ultimate design loads for wind turbines such that a service probabilistic design approaches for design of wind turbines against extreme limit states. Several different

  18. Effectiveness of Changing Wind Turbine Cut-in Speed to Reduce Bat Fatalities at Wind Facilities

    SciTech Connect

    Huso, Manuela M. P.; Hayes, John P.

    2009-04-01

    This report details an experiment on the effectiveness of changing wind turbine cut-in speed on reducing bat fatality from wind turbines at the Casselman Wind Project in Somerset County, Pennsylvania.

  19. Time-frequency methods for signal analysis in wind turbines

    NASA Astrophysics Data System (ADS)

    Kalista, Karel; Liska, Jindrich

    2015-11-01

    Since wind turbines became one of the most often source of renewable energy, appropriate health and condition monitoring systems are required. Especially proper monitoring of offshore plants is very significant because the accessibility is difficult and inspections are very costly. In comparison with conventional rotating machine vibration monitoring, where steady conditions and stationary signal are usually assumed, the wind turbines are characterized by unsteady conditions due to variable rotational speed. Hence the vibration signal is non-stationary and interpretation of signal signatures may be more complex. The common approach to analyze such non-stationary signals is the use of a time-frequency method, usually Short-Time Fourier Transform, which is the most popular one due to its simplicity. Nevertheless, there are other methods which can give a different view at the analyzed data and provide new information. This article investigates the potential use of some other time-frequency methods, namely Wavelet Transform, Wigner-Ville distribution and Hilbert-Huang transform in wind plants monitoring systems and apply these methods to real measured data with additional simulated bearing fault signal. Finally, the mentioned methods are compared based on computational complexity, readability and interpretability. Though the last two criteria are very subjective, Short-Time Fourier Transform was finally chosen as the most effective method followed by Wavelet Transform.

  20. Wind Turbine Generator System Duration Test Report for the ARE 442 Wind Turbine

    SciTech Connect

    van Dam, J.; Baker, D.; Jager, D.

    2010-05-01

    This test is being 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. In total, four turbines are being tested at the NWTC as a part of this project. Duration testing is one of up to 5 tests that may be performed on the turbines, including power performance, safety and function, noise, and power quality tests. The results of the testing provide manufacturers with reports that may be used for small wind turbine certification. The test equipment includes a grid connected ARE 442 wind turbine mounted on a 30.5 meter (100 ft) lattice tower manufactured by Abundant Renewable Energy. The system was installed by the NWTC Site Operations group with guidance and assistance from Abundant Renewable Energy.

  1. Optimizing wind turbine control system parameters

    NASA Astrophysics Data System (ADS)

    Schluter, Larry L.; Vachon, William A.

    1993-05-01

    The impending expiration of the levelized period in the Interim Standard Offer Number 4 (ISO4) utility contracts for purchasing wind-generated power in California mandates, more than ever, that windplants be operated in a cost-effective manner. Operating plans and approaches are needed that maximize the net revenue from wind parks--after accounting for operation and maintenance costs. This paper describes a design tool that makes it possible to tailor a control system of a wind turbine (WT) to maximize energy production while minimizing the financial consequences of fatigue damage to key structural components. Plans for code enhancements to include expert systems and fuzzy logic are discussed, and typical results are presented in which the code is applied to study the controls of a generic Danish 15-m horizontal axis wind turbine (HAWT).

  2. Figure 1: The trend in wind turbine size is to grow larger. Structural Health Monitoring of Wind Turbine Blades*

    E-print Network

    Figure 1: The trend in wind turbine size is to grow larger. Structural Health Monitoring of Wind Turbine Blades* Mark A. Rumsey and Joshua A. Paquette Sandia National Laboratories§ , Albuquerque, NM 87185 ABSTRACT As electric utility wind turbines increase in size, and correspondingly, increase

  3. Built-Environment Wind Turbine Roadmap

    SciTech Connect

    Smith, J.; Forsyth, T.; Sinclair, K.; Oteri, F.

    2012-11-01

    Although only a small contributor to total electricity production needs, built-environment wind turbines (BWTs) nonetheless have the potential to influence the public's consideration of renewable energy, and wind energy in particular. Higher population concentrations in urban environments offer greater opportunities for project visibility and an opportunity to acquaint large numbers of people to the advantages of wind projects on a larger scale. However, turbine failures will be equally visible and could have a negative effect on public perception of wind technology. This roadmap provides a framework for achieving the vision set forth by the attendees of the Built-Environment Wind Turbine Workshop on August 11 - 12, 2010, at the U.S. Department of Energy's National Renewable Energy Laboratory. The BWT roadmap outlines the stakeholder actions that could be taken to overcome the barriers identified. The actions are categorized as near-term (0 - 3 years), medium-term (4 - 7 years), and both near- and medium-term (requiring immediate to medium-term effort). To accomplish these actions, a strategic approach was developed that identifies two focus areas: understanding the built-environment wind resource and developing testing and design standards. The authors summarize the expertise and resources required in these areas.

  4. Wind turbine reliability :understanding and minimizing wind turbine operation and maintenance costs.

    SciTech Connect

    Walford, Christopher A. (Global Energy Concepts. Kirkland, WA)

    2006-03-01

    Wind turbine system reliability is a critical factor in the success of a wind energy project. Poor reliability directly affects both the project's revenue stream through increased operation and maintenance (O&M) costs and reduced availability to generate power due to turbine downtime. Indirectly, the acceptance of wind-generated power by the financial and developer communities as a viable enterprise is influenced by the risk associated with the capital equipment reliability; increased risk, or at least the perception of increased risk, is generally accompanied by increased financing fees or interest rates. This paper outlines the issues relevant to wind turbine reliability for wind turbine power generation projects. The first sections describe the current state of the industry, identify the cost elements associated with wind farm O&M and availability and discuss the causes of uncertainty in estimating wind turbine component reliability. The latter sections discuss the means for reducing O&M costs and propose O&M related research and development efforts that could be pursued by the wind energy research community to reduce cost of energy.

  5. Redesign of a wind turbine hub

    E-print Network

    Hunter-Jones, Bridget I

    2014-01-01

    The current designs of wind turbine hubs contain many faults. The slew ring bearing that connects the blade to the hub takes on a large bending moment that in many cases causes the joints to fail and the blade to break ...

  6. Root region airfoil for wind turbine

    DOEpatents

    Tangler, James L. (Boulder, CO); Somers, Dan M. (State College, PA)

    1995-01-01

    A thick airfoil for the root region of the blade of a wind turbine. The airfoil has a thickness in a range from 24%-26% and a Reynolds number in a range from 1,000,000 to 1,800,000. The airfoil has a maximum lift coefficient of 1.4-1.6 that has minimum sensitivity to roughness effects.

  7. Evaluation of airfoils for small wind turbines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new set of blades have been designed, fabricated, and tested at the United States Department of Agriculture-Agricultural Research Service-Conservation and Production Research Laboratory in Bushland, Texas in an attempt to improve the overall performance of small (1-10 kilowatt) wind turbines. The ...

  8. Infrasound from Wind Turbines Could Affect Humans

    ERIC Educational Resources Information Center

    Salt, Alec N.; Kaltenbach, James A.

    2011-01-01

    Wind turbines generate low-frequency sounds that affect the ear. The ear is superficially similar to a microphone, converting mechanical sound waves into electrical signals, but does this by complex physiologic processes. Serious misconceptions about low-frequency sound and the ear have resulted from a failure to consider in detail how the ear…

  9. Wooden wind turbine blade manufacturing process

    DOEpatents

    Coleman, Clint (Warren, VT)

    1986-01-01

    A wooden wind turbine blade is formed by laminating wood veneer in a compression mold having the exact curvature needed for one side of the blade, following which the other side of the blade is ground flat along its length but twisted with respect to the blade axis.

  10. Wind turbine performance under icing conditions

    SciTech Connect

    Jasinski, W.J.; Noe, S.C.; Selig, M.S.; Bragg, M.B.

    1998-02-01

    The effects of rime ice on horizontal axis wind turbine performance were estimated. For typical supercooled fog conditions found in cold northern regions, four rime ice accretions on the S809 wind turbine airfoil were predicted using the NASA LEWICE code. The resulting airfoil/ice profile combinations were wind tunnel tested to obtain the lift, drag, and pitching moment characteristics over the Reynolds number range 1--2 {times} 10{sup 6}. These data were used in the PROPID wind turbine performance prediction code to predict the effects of rime ice on a 450-kW rated-power, 28.7-m diameter turbine operated under both stall-regulated and variable-speed/variable-pitch modes. Performance losses on the order of 20% were observed for the variable-speed/variable-pitch rotor. For the stall-regulated rotor, however, a relatively small rime ice profile yielded significantly larger performance losses. For a larger 0.08c-long rime ice protrusion, however, the rated peak power was exceeded by 16% because at high angles the rime ice shape acted like a leading edge flap, thereby increasing the airfoil C{sub l,max} and delaying stall.

  11. Wind Turbine Tribology Seminar - A Recap

    SciTech Connect

    Errichello, R.; Sheng, S.; Keller, J.; Greco, A.

    2012-02-01

    Tribology is the science and engineering of interacting surfaces in relative motion. It includes the study and application of the principles of friction, lubrication, and wear. It is an important phenomenon that not only impacts the design and operation of wind turbine gearboxes, but also their subsequent maintenance requirements and overall reliability. With the major growth and increasing dependency on renewable energy, mechanical reliability is an extremely important issue. The Wind Turbine Tribology Seminar was convened to explore the state-of-the-art in wind turbine tribology and lubricant technologies, raise industry awareness of a very complex topic, present the science behind each technology, and identify possible R&D areas. To understand the background of work that had already been accomplished, and to consolidate some level of collective understanding of tribology by acknowledged experts, the National Renewable Energy Laboratory (NREL), Argonne National Laboratory (ANL), and the U.S. Department of Energy (DOE) hosted a wind turbine tribology seminar. It was held at the Renaissance Boulder Flatiron Hotel in Broomfield, Colorado on November 15-17, 2011. This report is a summary of the content and conclusions. The presentations given at the meeting can be downloaded. Interested readers who were not at the meeting may wish to consult the detailed publications listed in the bibliography section, obtain the cited articles in the public domain, or contact the authors directly.

  12. Power Performance Test Report for the SWIFT Wind Turbine

    SciTech Connect

    Mendoza, I.; Hur, J.

    2012-12-01

    This report summarizes the results of a power performance test that NREL conducted on the SWIFT wind turbine. This test was conducted in accordance with the International Electrotechnical Commission's (IEC) standard, Wind Turbine Generator Systems Part 12: Power Performance Measurements of Electricity Producing Wind Turbines, IEC 61400-12-1 Ed.1.0, 2005-12. However, because the SWIFT is a small turbine as defined by IEC, NREL also followed Annex H that applies to small wind turbines. In these summary results, wind speed is normalized to sea-level air density.

  13. Duration Test Report for the Viryd CS8 Wind Turbine

    SciTech Connect

    Roadman, J.; Murphy, M.; van Dam, J.

    2013-06-01

    This report summarizes the results of a duration noise test that the National Renewable Energy Laboratory (NREL) conducted on the Viryd CS8 wind turbine. This test was conducted in accordance with Clause 9.4 of the International Electrotechnical Commission's (IEC) standard, Wind turbines - Part 2: Design requirements for small wind turbines, IEC 61400-2 Ed. 2.0:2006-03. NREL researchers evaluated the turbine based on structural integrity and material degradation, quality of environmental protection, and dynamic behavior.

  14. Effects of Changing Atmospheric Conditions on Wind Turbine Performance (Poster)

    SciTech Connect

    Clifton, A.

    2012-12-01

    Multi-megawatt, utility-scale wind turbines operate in turbulent and dynamic winds that impact turbine performance in ways that are gradually becoming better understood. This poster presents a study made using a turbulent flow field simulator (TurbSim) and a Turbine aeroelastic simulator (FAST) of the response of a generic 1.5 MW wind turbine to changing inflow. The turbine power output is found to be most sensitive to wind speed and turbulence intensity, but the relationship depends on the wind speed with respect to the turbine's rated wind speed. Shear is found to be poorly correlated to power. A machine learning method called 'regression trees' is used to create a simple model of turbine performance that could be used as part of the wind resource assessment process. This study has used simple flow fields and should be extended to more complex flows, and validated with field observations.

  15. 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.

  16. The Mod-2 wind turbine development project

    NASA Technical Reports Server (NTRS)

    Linscott, B. S.; Dennett, J. T.; Gordon, L. H.

    1981-01-01

    A major phase of the Federal Wind Energy Program, the Mod-2 wind turbine, a second-generation machine developed by the Boeing Engineering and Construction Co. for the U.S. Department of Energy and the Lewis Research Center of the National Aeronautics and Space Administration, is described. The Mod-2 is a large (2.5-MW power rating) horizontal-axis wind turbine designed for the generation of electrical power on utility networks. Three machines were built and are located in a cluster at Goodnoe Hills, Washington. All technical aspects of the project are described: design approach, significant innovation features, the mechanical system, the electrical power system, the control system, and the safety system.

  17. RESEARCH ARTICLE Dynamic wind loads and wake characteristics of a wind turbine

    E-print Network

    Hu, Hui

    RESEARCH ARTICLE Dynamic wind loads and wake characteristics of a wind turbine model of the unsteady vortex and turbulent flow structures in the near wake of a horizontal axis wind turbine model.e., aerodynamic forces and bending moments) acting on the wind turbine model by using a high-sensitive force

  18. Probabilistic fatigue methodology and wind turbine reliability

    SciTech Connect

    Lange, C.H.

    1996-05-01

    Wind turbines subjected to highly irregular loadings due to wind, gravity, and gyroscopic effects are especially vulnerable to fatigue damage. The objective of this study is to develop and illustrate methods for the probabilistic analysis and design of fatigue-sensitive wind turbine components. A computer program (CYCLES) that estimates fatigue reliability of structural and mechanical components has been developed. A FORM/SORM analysis is used to compute failure probabilities and importance factors of the random variables. The limit state equation includes uncertainty in environmental loading, gross structural response, and local fatigue properties. Several techniques are shown to better study fatigue loads data. Common one-parameter models, such as the Rayleigh and exponential models are shown to produce dramatically different estimates of load distributions and fatigue damage. Improved fits may be achieved with the two-parameter Weibull model. High b values require better modeling of relatively large stress ranges; this is effectively done by matching at least two moments (Weibull) and better by matching still higher moments. For this purpose, a new, four-moment {open_quotes}generalized Weibull{close_quotes} model is introduced. Load and resistance factor design (LRFD) methodology for design against fatigue is proposed and demonstrated using data from two horizontal-axis wind turbines. To estimate fatigue damage, wind turbine blade loads have been represented by their first three statistical moments across a range of wind conditions. Based on the moments {mu}{sub 1}{hor_ellipsis}{mu}{sub 3}, new {open_quotes}quadratic Weibull{close_quotes} load distribution models are introduced. The fatigue reliability is found to be notably affected by the choice of load distribution model.

  19. Mod-2 wind turbine field operations experiment

    NASA Technical Reports Server (NTRS)

    Gordon, L. H.

    1985-01-01

    The three-machine, 7.5 MW Goodnoe Hills located near Goldendale, Washington and is now in a research/experimental operations phase that offers a unique opportunity to study the effects of single and multiple wind turbines interacting with each other, the power grid; and the environment. Following a brief description of the turbine and project history, this paper addresses major problem areas and research and development test results. Field operations, both routine and nonroutine, are discussed. Routine operation to date has produced over 13,379,000 KWh of electrical energy during 11,064 hr of rotation. Nonroutine operation includes suspended activities caused by a crack in the low speed shaft that necessitated a redesign and reinstallation of this assembly on all three turbines. With the world's largest cluster back in full operation, two of the turbines will be operated over the next years to determine their value as energy producer. The third unit will be used primarily for conducting research tests requiring configuration changes to better understand the wind turbine technology. Technical areas summarized pertain to system performance and enhancements. Specific research tests relating to acoustics, TV interference, and wake effects conclude the paper.

  20. Wind turbine reliability : understanding and minimizing wind turbine operation and maintenance costs.

    SciTech Connect

    Not Available

    2004-11-01

    Wind turbine system reliability is a critical factor in the success of a wind energy project. Poor reliability directly affects both the project's revenue stream through increased operation and maintenance (O&M) costs and reduced availability to generate power due to turbine downtime. Indirectly, the acceptance of wind-generated power by the financial and developer communities as a viable enterprise is influenced by the risk associated with the capital equipment reliability; increased risk, or at least the perception of increased risk, is generally accompanied by increased financing fees or interest rates. Cost of energy (COE) is a key project evaluation metric, both in commercial applications and in the U.S. federal wind energy program. To reflect this commercial reality, the wind energy research community has adopted COE as a decision-making and technology evaluation metric. The COE metric accounts for the effects of reliability through levelized replacement cost and unscheduled maintenance cost parameters. However, unlike the other cost contributors, such as initial capital investment and scheduled maintenance and operating expenses, costs associated with component failures are necessarily speculative. They are based on assumptions about the reliability of components that in many cases have not been operated for a complete life cycle. Due to the logistical and practical difficulty of replacing major components in a wind turbine, unanticipated failures (especially serial failures) can have a large impact on the economics of a project. The uncertainty associated with long-term component reliability has direct bearing on the confidence level associated with COE projections. In addition, wind turbine technology is evolving. New materials and designs are being incorporated in contemporary wind turbines with the ultimate goal of reducing weight, controlling loads, and improving energy capture. While the goal of these innovations is reduction in the COE, there is a potential impact on reliability whenever new technologies are introduced. While some of these innovations may ultimately improve reliability, in the short term, the technology risks and the perception of risk will increase. The COE metric used by researchers to evaluate technologies does not address this issue. This paper outlines the issues relevant to wind turbine reliability for wind turbine power generation projects. The first sections describe the current state of the industry, identify the cost elements associated with wind farm O&M and availability and discuss the causes of uncertainty in estimating wind turbine component reliability. The latter sections discuss the means for reducing O&M costs and propose O&M related research and development efforts that could be pursued by the wind energy research community to reduce COE.

  1. Dynamic Models for Wind Turbines and Wind Power Plants

    SciTech Connect

    Singh, M.; Santoso, S.

    2011-10-01

    The primary objective of this report was to develop universal manufacturer-independent wind turbine and wind power plant models that can be shared, used, and improved without any restrictions by project developers, manufacturers, and engineers. Manufacturer-specific models of wind turbines are favored for use in wind power interconnection studies. While they are detailed and accurate, their usages are limited to the terms of the non-disclosure agreement, thus stifling model sharing. The primary objective of the work proposed is to develop universal manufacturer-independent wind power plant models that can be shared, used, and improved without any restrictions by project developers, manufacturers, and engineers. Each of these models includes representations of general turbine aerodynamics, the mechanical drive-train, and the electrical characteristics of the generator and converter, as well as the control systems typically used. To determine how realistic model performance is, the performance of one of the models (doubly-fed induction generator model) has been validated using real-world wind power plant data. This work also documents selected applications of these models.

  2. SUSTAINABLE CONCRETE FOR WIND TURBINE FOUNDATIONS.

    SciTech Connect

    BERNDT,M.L.

    2004-06-01

    The use of wind power to generate electricity continues to grow, especially given commitments by various countries throughout the world to ensure that a significant percentage of energy comes from renewable sources. In order to meet such objectives, increasingly larger turbines with higher capacity are being developed. The engineering aspects of larger turbine development tend to focus on design and materials for blades and towers. However, foundations are also a critical component of large wind turbines and represent a significant cost of wind energy projects. Ongoing wind research at BNL is examining two areas: (a) structural response analysis of wind turbine-tower-foundation systems and (b) materials engineering of foundations. This work is investigating the dynamic interactions in wind turbine systems, which in turn assists the wind industry in achieving improved reliability and more cost efficient foundation designs. The results reported herein cover initial studies of concrete mix designs for large wind turbine foundations and how these may be tailored to reduce cost and incorporate sustainability and life cycle concepts. The approach taken was to investigate material substitutions so that the environmental, energy and CO{sub 2}-impact of concrete could be reduced. The use of high volumes of ''waste'' materials in concrete was examined. These materials included fly ash, blast furnace slag and recycled concrete aggregate. In addition, the use of steel fiber reinforcement as a means to improve mechanical properties and potentially reduce the amount of bar reinforcement in concrete foundations was studied. Four basic mixes were considered. These were: (1) conventional mix with no material substitutions, (2) 50% replacement of cement with fly ash, (3) 50% replacement of cement with blast furnace slag and (4) 25% replacement of cement with fly ash and 25% replacement with blast furnace slag. Variations on these mixes included the addition of 1% by volume steel fibers. The use of recycled concrete aggregate in the conventional and 50% slag mixes was also studied. Properties investigated included compressive and tensile strengths, elastic modulus, coefficient of permeability, thermal conductivity and durability in seawater and sulfate solutions. It was determined that the mixes containing 50% slag gave the best overall performance. Slag was particularly beneficial for concrete that used recycled aggregate and could reduce strength losses. Initial durability results indicated that corrosion of fibers in the different concrete mixes when exposed to seawater was minimal. Future research needs to include more detailed studies of mix design and properties of concrete for wind turbine foundations. Emphasis on slag-modified mixes with natural and recycled concrete aggregate is recommended. The proportion of slag that can be incorporated in the concrete needs to be optimized, as does the grading of recycled aggregate. The potential for using silica fume in conjunction with slag is worth exploring as this may further enhance strength and durability. Longer-term durability studies are necessary and other pertinent properties of concrete that require investigation include damping characteristics, pullout strength, fatigue strength and risk of thermal cracking. The properties of sustainable concrete mixes need to be integrated with studies on the structural behavior of wind turbine foundations in order to determine the optimal mix design and to examine means of reducing conservatism and cost of foundations.

  3. 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.

  4. 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.

  5. PARAMETRIC MODELS FOR ESTIMATING WIND TURBINE FATIGUE LOADS FOR DESIGN

    E-print Network

    Sweetman, Bert

    1 PARAMETRIC MODELS FOR ESTIMATING WIND TURBINE FATIGUE LOADS FOR DESIGN Lance Manuel1 Paul S-4020 ABSTRACT International standards for wind turbine certification depend on finding long-term fatigue load-bending data from a commercial turbine in complex terrain. Distributions of rainflow-counted range data

  6. Offshore Series Wind Turbine Variable Hub heights & rotor diameters

    E-print Network

    Firestone, Jeremy

    3.6MW Offshore Series Wind Turbine GE Energy #12;Feature Variable Hub heights & rotor diameters and providing longer turbine life GE's unique electronics provide transmission efficiencies and enable harmonious function within the local grid Allows wind turbines to stay on line generating power, even during

  7. continuum mechanics inviscid fluids Efficiency of a Wind Turbine

    E-print Network

    continuum mechanics inviscid fluids Efficiency of a Wind Turbine In this problem, we will determine the maximal possible power that can be extracted from a wind turbine. We imagine the following setup. Consider a tube of cross-sectional area A, with incident gas velocity v. We place some turbine

  8. AIAA-2001-0046 PREDICTING DESIGN WIND TURBINE LOADS

    E-print Network

    AIAA-2001-0046 PREDICTING DESIGN WIND TURBINE LOADS FROM LIMITED DATA: COMPARING RANDOM PROCESS topics that arise in reliability-based wind turbine design. First, it illustrates how general probability flap and edge bending loads in both parked and operating turbine conditions. In particular, a 3-moment

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

    SciTech Connect

    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.

  10. 66 APRIL | 2010 The FuTure oF Wind Turbine

    E-print Network

    Kusiak, Andrew

    66 APRIL | 2010 The FuTure oF Wind Turbine diagnosTics Wind energy is undergoing expansion in the form of large-scale wind farms, wind energy cooperatives, wind turbines owned by indi- vidual investors of wind turbines, operation and maintenance (O&M) costs remain high due to failures of wind turbine

  11. Wind turbine reliability database update.

    SciTech Connect

    Peters, Valerie A.; Hill, Roger Ray; Stinebaugh, Jennifer A.; Veers, Paul S.

    2009-03-01

    This report documents the status of the Sandia National Laboratories' Wind Plant Reliability Database. Included in this report are updates on the form and contents of the Database, which stems from a fivestep process of data partnerships, data definition and transfer, data formatting and normalization, analysis, and reporting. Selected observations are also reported.

  12. Wind turbine wake detection with a single Doppler wind lidar

    NASA Astrophysics Data System (ADS)

    Wang, H.; Barthelmie, R. J.

    2015-06-01

    Using scanning lidar wind turbine wakes can be probed in three dimensions to produce a wealth of temporally and spatially irregular data that can be used to characterize the wakes. Unlike data from a meteorological mast or upward pointing lidar, the spatial coordinates of the measurements are not fixed and the location of the wake also varies in three dimensions. Therefore the challenge is to provide automated detection algorithms to identify wakes and quantify wake characteristics from this type of dataset. Here an algorithm is developed and evaluated on data from a large wind farm in the Midwest. A scanning coherent Doppler wind lidar was configured to measure wind speed in the wake of a continuously yawing wind turbine for two days during the experiment and wake profiles were retrieved with input of wind direction information from the nearby meteorological mast. Additional challenges to the analysis include incomplete coverage of the entire wake due to the limited scanning domain, and large wind shear that can contaminate the wake estimate because of the height variation along the line-of-sight. However, the algorithm developed in this paper is able to automatically capture wakes in lidar data from Plan Position Indicator (PPI) scans and the resultant wake statistics are consistent with previous experiment's results.

  13. Utility Scale Wind turbine Demonstration Project

    SciTech Connect

    Terry Fredericks

    2006-03-31

    The purpose of the Three Affiliated Tribes proposing to Department of Energy was nothing new to Denmark. National Meteorological Studies have proved that North Dakota has some of the most consistence wind resources in the world. The Three Affiliated Tribes wanted to assess their potential and become knowledgeable to developing this new and upcoming resource now valuable. By the Tribe implementing the Utility-scale Wind Turbine Project on Fort Berthold, the tribe has proven the ability to complete a project, and has already proceeded in a feasibility studies to developing a large-scale wind farm on the reservation due to tribal knowledge learned, public awareness, and growing support of a Nation wanting clean renewable energy. The tribe is working through the various measures and regulations with the want to be self-sufficient, independent, and marketable with 17,000 times the wind energy needed to service Fort Berthold alone.

  14. Wear Analysis of Wind Turbine Gearbox Bearings

    SciTech Connect

    Blau, Peter Julian; Walker, Larry R; Xu, Hanbing; Parten, Randy J; Qu, Jun; Geer, Tom

    2010-04-01

    The objective of this effort was to investigate and characterize the nature of surface damage and wear to wind turbine gearbox bearings returned from service in the field. Bearings were supplied for examination by S. Butterfield and J. Johnson of the National Wind Technology Center (NREL), Boulder, Colorado. Studies consisted of visual examination, optical and electron microscopy, dimensional measurements of wear-induced macro-scale and micro-scale features, measurements of macro- and micro-scale hardness, 3D imaging of surface damage, studies of elemental distributions on fracture surfaces, and examinations of polished cross-sections of surfaces under various etched and non-etched conditions.

  15. Root region airfoil for wind turbine

    DOEpatents

    Tangler, J.L.; Somers, D.M.

    1995-05-23

    A thick airfoil is described for the root region of the blade of a wind turbine. The airfoil has a thickness in a range from 24%--26% and a Reynolds number in a range from 1,000,000 to 1,800,000. The airfoil has a maximum lift coefficient of 1.4--1.6 that has minimum sensitivity to roughness effects. 3 Figs.

  16. Wind Turbine Generator System Duration Test Report for the Gaia-Wind 11 kW Wind Turbine

    SciTech Connect

    Huskey, A.; Bowen, A.; Jager, D.

    2010-09-01

    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. In total, five turbines are being tested at the National Renewable Energy Laboratory's (NRELs) National Wind Technology Center (NWTC) as a part of this project. Duration testing is one of up to five tests that may be performed on the turbines, including power performance, safety and function, noise, and power quality tests. The results of the testing will provide the manufacturers with reports that may be used for small wind turbine certification. The test equipment includes a Gaia-Wind 11 kW wind turbine mounted on an 18 m monopole tower. Gaia-Wind Ltd. manufactured the turbine in Denmark, although the company is based in Scotland. The system was installed by the NWTC Site Operations group with guidance and assistance from Gaia-Wind.

  17. Flow separation on wind turbines blades

    NASA Astrophysics Data System (ADS)

    Corten, G. P.

    2001-01-01

    In the year 2000, 15GW of wind power was installed throughout the world, producing 100PJ of energy annually. This contributes to the total electricity demand by only 0.2%. Both the installed power and the generated energy are increasing by 30% per year world-wide. If the airflow over wind turbine blades could be controlled fully, the generation efficiency and thus the energy production would increase by 9%. Power Control To avoid damage to wind turbines, they are cut out above 10 Beaufort (25 m/s) on the wind speed scale. A turbine could be designed in such a way that it converts as much power as possible in all wind speeds, but then it would have to be to heavy. The high costs of such a design would not be compensated by the extra production in high winds, since such winds are rare. Therefore turbines usually reach maximum power at a much lower wind speed: the rated wind speed, which occurs at about 6 Beaufort (12.5 m/s). Above this rated speed, the power intake is kept constant by a control mechanism. Two different mechanisms are commonly used. Active pitch control, where the blades pitch to vane if the turbine maximum is exceeded or, passive stall control, where the power control is an implicit property of the rotor. Stall Control The flow over airfoils is called "attached" when it flows over the surface from the leading edge to the trailing edge. However, when the angle of attack of the flow exceeds a certain critical angle, the flow does not reach the trailing edge, but leaves the surface at the separation line. Beyond this line the flow direction is reversed, i.e. it flows from the trailing edge backward to the separation line. A blade section extracts much less energy from the flow when it separates. This property is used for stall control. Stall controlled rotors always operate at a constant rotation speed. The angle of attack of the flow incident to the blades is determined by the blade speed and the wind speed. Since the latter is variable, it determines the angle of attack. The art of designing stall rotors is to make the separated area on the blades extend in such a way, that the extracted power remains precisely constant, independent of the wind speed, while the power in the wind at cut-out exceeds the maximum power of the turbine by a factor of 8. Since the stall behaviour is influenced by many parameters, this demand cannot be easily met. However, if it can be met, the advantage of stall control is its passive operation, which is reliable and cheap. Problem Definition In practical application, stall control is not very accurate and many stall-controlled turbines do not meet their specifications. Deviations of the design-power in the order of tens of percent are regular. In the nineties, the aerodynamic research on these deviations focussed on: profile aerodynamics, computational fluid dynamics, rotational effects on separation and pressure measurements on test turbines. However, this did not adequately solve the actual problems with stall turbines. In this thesis, we therefore formulated the following as the essential question: "Does the separated blade area really extend with the wind speed, as we predict?" To find the answer a measurement technique was required, which 1) was applicable on large commercial wind turbines, 2) could follow the dynamic changes of the stall pattern, 3) was not influenced by the centrifugal force and 4) did not disturb the flow. Such a technique was not available, therefore we decided to develop it. Stall Flag Method For this method, a few hundred indicators are fixed to the rotor blades in a special pattern. These indicators, called "stall flags" are patented by the Netherlands Energy Research Foundation (ECN). They have a retro-reflective area which, depending on the flow direction, is or is not covered. A powerful light source in the field up to 500m behind the turbine illuminates the swept rotor area. The uncovered reflectors reflect the light to the source, where a digital video camera records the dynamic stall patterns. The images are analyse

  18. On the Modelling of a Floating Offshore Wind Turbine

    NASA Astrophysics Data System (ADS)

    Henderson, Andrew R.; Patel, Minoo H.

    2003-01-01

    The location of wind turbines on floating structures offshore would allow an immense resource to be tapped without the drawbacks large developments can have on public opinion. There are, however, potentially significant technical and cost drawbacks. This article describes the theory and results of research work aimed at developing analytical tools for evaluating the performance of floating offshore wind farms. The principal problem addressed here is the development of analytical tools for modelling the turbine loads and fatigue damage due to the vessel motion. The effect that the motion would have on the wind turbine is found by calculating the aerodynamic and inertial loads on the blades in a two-dimensional state domain representing the blade and the vessel motion respectively. Using a double Fourier transform, discrete deterministic frequency spectra of the loads are found and the fatigue damage is evaluated. Undertaking the calculations for vessel motion in each degree of freedom allows appropriate weightings to be developed, which can be used for the optimization of candidate supporting vessels by evaluating the motion response directly.

  19. WEST-3 wind turbine simulator development

    NASA Technical Reports Server (NTRS)

    Hoffman, J. A.; Sridhar, S.

    1985-01-01

    The software developed for WEST-3, a new, all digital, and fully programmable wind turbine simulator is given. The process of wind turbine simulation on WEST-3 is described in detail. The major steps are, the processing of the mathematical models, the preparation of the constant data, and the use of system software generated executable code for running on WEST-3. The mechanics of reformulation, normalization, and scaling of the mathematical models is discussed in detail, in particulr, the significance of reformulation which leads to accurate simulations. Descriptions for the preprocessor computer programs which are used to prepare the constant data needed in the simulation are given. These programs, in addition to scaling and normalizing all the constants, relieve the user from having to generate a large number of constants used in the simulation. Also given are brief descriptions of the components of the WEST-3 system software: Translator, Assembler, Linker, and Loader. Also included are: details of the aeroelastic rotor analysis, which is the center of a wind turbine simulation model, analysis of the gimbal subsystem; and listings of the variables, constants, and equations used in the simulation.

  20. 36 SEPTEMBER | 2012 WiNd TURbiNE CAPACiTY

    E-print Network

    Kusiak, Andrew

    36 SEPTEMBER | 2012 WiNd TURbiNE CAPACiTY FRONTiER FROM SCAdA ThE WORld hAS SEEN A significant contributor to this growth. The wind turbine generated energy depends on the wind potential and the turbine of wind turbines. Supervi- sory control and data acquisition (SCADA) systems record wind turbine

  1. Aalborg Universitet Harmonic Analysis of Offshore Wind Farms with Full Converter Wind Turbines

    E-print Network

    Bak, Claus Leth

    Aalborg Universitet Harmonic Analysis of Offshore Wind Farms with Full Converter Wind Turbines International Conference on Large-Scale Integration of Wind Power into Power Systems Publication date: 2009 Analysis of Offshore Wind Farms with Full Converter Wind Turbines. In Proceeding of the 8th International

  2. An overview of DOE's wind turbine development programs

    NASA Astrophysics Data System (ADS)

    Laxson, A. S.; Hock, S. M.; Musial, W. D.; Goldman, P. R.

    1992-12-01

    The development of technologically advanced, higher efficiency wind turbines continues to be a high priority of the US wind industry. The United States Department of Energy (DOE) is conducting and sponsoring a range of programs aimed at assisting the wind industry with system design, development, and testing. The overall goal is to develop systems that can compete with conventional electric generation at $0.05/kWh at 5.8 m/s (13 mph sites) by the mid-1990s, and with fossil-fuel-based generators $0.04/kWh at 5.8 m/s sites by the year 2000. These goals will be achieved through several programs. The Value Engineered Turbine (VET) Program will promote the rapid development of US capability to manufacture wind turbines to take advantage of near-term market opportunities. These value-engineered turbines will stem from units with known and well-documented records of performance. The Advanced Wind Turbine Program will assist US industry to develop and integrate advanced technologies into utility-grade wind turbines for the near term (1993-1995), and to develop a new generation of innovative turbines for the year 2000. The Utility Wind Turbine Performance Verification Program, a collaborative agreement between the Electric Power Research Institute (EPRI) and DOE, will deploy and evaluate commercial-prototype wind turbines in typical utility operating environments to provide a bridge from development programs currently under way to commercial purchases of utility-grade wind turbines.

  3. An overview of DOE's wind turbine development programs

    SciTech Connect

    Laxson, A.S.; Hock, S.M.; Musial, W.D. ); Goldman, P.R. )

    1992-12-01

    The development of technologically advanced, higher efficiency wind turbines continues to be a high priority of the US wind industry. The United States Department of Energy (DOE) is conducting and sponsoring a range of programs aimed at assisting the wind industry with system design, development, and testing. The overall goal is to develop systems that can compete with conventional electric generation at $0.05/kWh at 5.8 m/s (13 mph sites) by the mid-1990s, and with fossil-fuel-based generators $0.04/kWh at 5.8 m/s sites by the year 2000. These goals will be achieved through several programs. The Value Engineered Turbine (VET) Program will promote the rapid development of US capability to manufacture wind turbines to take advantage of near-term market opportunities. These value-engineered turbines will stem from units with known and well-documented records of performance. The Advanced Wind Turbine Program will assist US industry to develop and integrate advanced technologies into utility-grade wind turbines for the near term (1993--1995), and to develop a new generation of innovative turbines for the year 2000. The Utility Wind Turbine Performance Verification Program, a collaborative agreement between the Electric Power Research Institute (EPRI) and DOE, will deploy and evaluate commercial-prototype wind turbines in typical utility operating environments to provide a bridge from development programs currently under way to commercial purchases of utility-grade wind turbines.

  4. Siting guidelines for utility application of wind turbines. Final report

    SciTech Connect

    Pennell, W.T.

    1983-01-01

    Utility-oriented guidelines are described for identifying viable sites for wind turbines. Topics and procedures are also discussed that are important in carrying out a wind turbine siting program. These topics include: a description of the Department of Energy wind resource atlases; procedures for predicting wind turbine performance at potential sites; methods for analyzing wind turbine economics; procedures for estimating installation and maintenance costs; methods for anlayzing the distribution of wind resources over an area; and instrumentation for documenting wind behavior at potential sites. The procedure described is applicable to small and large utilities. Although the procedure was developed as a site-selection tool, it can also be used by a utility who wishes to estimate the potential for wind turbine penetration into its future generation mix.

  5. Power optimization of wind farms by curtailment of upwind turbines

    E-print Network

    Power optimization of wind farms by curtailment of upwind turbines Simon Kirkeby Wessel Kongens is shown to increase the total power production of wind farms of dierent size and shape. Several methods by curtailing upwind turbines. It is shown that the annual power production for a square wind farm consisting

  6. Bats and offshore wind turbines studied in southern Scandinavia

    E-print Network

    Bats and offshore wind turbines studied in southern Scandinavia 2005 - 2006 Bats & Wind Energy Pettersson Presented by Ingemar Ahlén #12;Bats and offshore wind turbines studied in southern Scandinavia Ahlén, Lothar Bach, Hans Baagøe & Jan Pettersson Bat photo: Björn Söderlund #12;Project management

  7. Coordinate Control of Wind Turbine and Battery in Wind Turbine Generator System

    NASA Astrophysics Data System (ADS)

    Senjyu, Tomonobu; Kikunaga, Yasuaki; Tokudome, Motoki; Uehara, Akie; Yona, Atsushi; Funabashi, Toshihisa

    Battery is installed for with wind power generator to level the output power fluctuations, since output power fluctuations of wind power generator are large. However, if large battery is installed in wind turbine generator, the capital cost for wind power system will increase. Hence, the smallest size of battery should be preferable to save the capital cost. In this paper, we propose a methodology for controlling combined system output power and storage energy capacity of battery system. The system consists of wind turbine generator and battery energy storage system. The generated power fluctuation in low and high frequency range are smoothed by pitch angle control and battery charge or discharge. This coordinated control reduces the rated battery capacity and windmill blade stress. In our proposed method, we apply H? control theory to achieve good response and robustness. The effectiveness of the proposed control system is simulated.

  8. Wind Turbine Generator System Safety and Function Test Report for the Southwest Windpower H40 Wind Turbine

    SciTech Connect

    van Dam, J.; Link, H.; Meadors, M.; Bianchi, J.

    2002-06-01

    The objective of this test was to evaluate the safety and function characteristics of the Whisper H40 wind turbine. The general requirements of wind turbine safety and function tests are defined in the IEC standard WT01. The testing was conducted in accordance with the National Wind Technology Center (NWTC) Quality Assurance System, including the NWTC Certification Team Certification Quality Manual and the NWTC Certification Team General Quality Manual for the Testing of Wind Turbines, as well as subordinate documents. This safety and function test was performed as part of the U.S. Department of Energy's Field Verification Program for small wind turbines.

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

    SciTech Connect

    Brock, Billy C.; Loui, Hung; McDonald, Jacob J.; Paquette, Joshua A.; Calkins, David A.; Miller, William K.; Allen, Steven E.; Clem, Paul Gilbert; Patitz, Ward E.

    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, 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.

  10. 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.

  11. Wind turbine inspection tests at UCSD

    NASA Astrophysics Data System (ADS)

    Tippmann, Jeffery D.; Manohar, Arun; Lanza di Scalea, Francesco

    2012-04-01

    The wind energy industry is rapidly growing in order to meet the increasing world energy demands as well as the need for clean and renewable energy sources. With the goal to explore new technologies and innovations which could help potentially improve the efficiency and effectiveness of wind energy, the NDE/SHM laboratory at UCSD acquired a unique wind turbine blade that will be used for performing several research projects related to wind turbine blade technology and non-destructive inspection techniques. The blade was built using the CX-100 design developed by TPI Composites, Inc. and Sandia National Laboratory (SNL). The 9-m blade was constructed with several embedded defects that represent the most common manufacturing defects typically found, such as out-of-plane waviness, composite delamination, and adhesive disbond. The defects were embedded during the manufacturing process by using similar methods developed by both TPI and SNL for simulating actual defect characteristics. Though the blade is small in comparison to the average utility sized blade of around 40 meters, the blade features similar materials and manufacturing methods, allowing for several inspections techniques to be studied on a representative platform. The inspection techniques include advanced infrared thermography and other guided wave techniques.

  12. Wind turbine rotor speed control system

    SciTech Connect

    Kisovec, A.V.

    1982-10-26

    A wind turbine rotor speed control for ensuring a constant rotational speed within tight tolerances includes a self-sufficient rotor incorporating aerodynamic and mechanical devices to provide the control. There is a fixed turbine blade adapted to be mounted on a shaft for rotation therewith, the fixed blade having pivotal blade tips at its respective ends. The pitch control of the blade tips regulates the rotor speed. Aerodynamic tabs are pivotally secured adjacent each of the ends of the respective trailing edges of the fixed blade. The relative wind acts on each tab which is connected to a series of links and pitch cams to regulate the pitch of the blade tips from a feathered position, to a cut-in position, to a rated wind position, and vice-versa. There are torque cams actuated by torsional strain on the shaft bearing which is connected to the shaft and to the pitch cams by a series of links so that as the wind approaches its rated velocity value the pitch cams become ineffective and the torque cams take over the speed control. There are also overspeed centrifugal devices connected to the pitch cams to cause the blade tips to feather in emergency overspeed conditions so as to stop the rotor.

  13. Superconductivity for Large Scale Wind Turbines

    SciTech Connect

    R. Fair; W. Stautner; M. Douglass; R. Rajput-Ghoshal; M. Moscinski; P. Riley; D. Wagner; J. Kim; S. Hou; F. Lopez; K. Haran; J. Bray; T. Laskaris; J. Rochford; R. Duckworth

    2012-10-12

    A conceptual design has been completed for a 10MW superconducting direct drive wind turbine generator employing low temperature superconductors for the field winding. Key technology building blocks from the GE Wind and GE Healthcare businesses have been transferred across to the design of this concept machine. Wherever possible, conventional technology and production techniques have been used in order to support the case for commercialization of such a machine. Appendices A and B provide further details of the layout of the machine and the complete specification table for the concept design. Phase 1 of the program has allowed us to understand the trade-offs between the various sub-systems of such a generator and its integration with a wind turbine. A Failure Modes and Effects Analysis (FMEA) and a Technology Readiness Level (TRL) analysis have been completed resulting in the identification of high risk components within the design. The design has been analyzed from a commercial and economic point of view and Cost of Energy (COE) calculations have been carried out with the potential to reduce COE by up to 18% when compared with a permanent magnet direct drive 5MW baseline machine, resulting in a potential COE of 0.075 $/kWh. Finally, a top-level commercialization plan has been proposed to enable this technology to be transitioned to full volume production. The main body of this report will present the design processes employed and the main findings and conclusions.

  14. 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.

  15. 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.

  16. Wind Turbine Pitch Optimization Benjamin Biegel Morten Juelsgaard Matt Kraning Stephen Boyd Jakob Stoustrup

    E-print Network

    Wind Turbine Pitch Optimization Benjamin Biegel Morten Juelsgaard Matt Kraning Stephen Boyd Jakob-controlled wind tur- bine. When placed in a wind field, the turbine experiences several mechanical loads, which measurements, with no knowledge of the wind field or wind turbine model. I. INTRODUCTION Wind turbines

  17. Structural Dynamic Behavior of Wind Turbines

    NASA Technical Reports Server (NTRS)

    Thresher, Robert W.; Mirandy, Louis P.; Carne, Thomas G.; Lobitz, Donald W.; James, George H. III

    2009-01-01

    The structural dynamicist s areas of responsibility require interaction with most other members of the wind turbine project team. These responsibilities are to predict structural loads and deflections that will occur over the lifetime of the machine, ensure favorable dynamic responses through appropriate design and operational procedures, evaluate potential design improvements for their impact on dynamic loads and stability, and correlate load and control test data with design predictions. Load prediction has been a major concern in wind turbine designs to date, and it is perhaps the single most important task faced by the structural dynamics engineer. However, even if we were able to predict all loads perfectly, this in itself would not lead to an economic system. Reduction of dynamic loads, not merely a "design to loads" policy, is required to achieve a cost-effective design. The two processes of load prediction and structural design are highly interactive: loads and deflections must be known before designers and stress analysts can perform structural sizing, which in turn influences the loads through changes in stiffness and mass. Structural design identifies "hot spots" (local areas of high stress) that would benefit most from dynamic load alleviation. Convergence of this cycle leads to a turbine structure that is neither under-designed (which may result in structural failure), nor over-designed (which will lead to excessive weight and cost).

  18. 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).

  19. 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.

  20. 77 FR 32497 - Grant of Authority for Subzone Status; Mitsubishi Power Systems Americas, Inc. (Wind Turbine...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-01

    ...Power Systems Americas, Inc. (Wind Turbine Nacelles and Generating Sets) Fort Smith...special-purpose subzone at the wind turbine nacelle and generating set manufacturing...activity related to the manufacturing of wind turbine nacelles and generating sets at the...

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

    E-print Network

    Hu, Hui

    acting on a wind turbine model Wei Tian, Ahmet Ozbay, and Hui Hu Citation: Physics of Fluids (1994 in a wind turbine wake Phys. Fluids 25, 117102 (2013); 10.1063/1.4824734 Distribution of spanwise enstrophy (2013); 10.1063/1.4807074 Large eddy simulation study of scalar transport in fully developed wind-turbine

  2. WIND-TUNNEL STUDY ON AERODYNAMIC PERFORMANCE OF SMALL VERTICAL-AXIS WIND TURBINES

    E-print Network

    Leu, Tzong-Shyng "Jeremy"

    1 WIND-TUNNEL STUDY ON AERODYNAMIC PERFORMANCE OF SMALL VERTICAL-AXIS WIND TURBINES J. J. Miau*1 were carried out to study the aerodynamic performance of three vertical axis wind turbines (VAWTs-stream turbulence intensity, at two tip speed ratios. Keywords: wind-tunnel experiment, VAWT, aerodynamic

  3. Wind Farm Simulations Using a Full Rotor Model for Wind Turbines

    E-print Network

    Mavripli, Dimitri J.

    Wind Farm Simulations Using a Full Rotor Model for Wind Turbines Jay Sitaraman Dimitri Mavriplis Earl P Duque Abstract Flow-field simulation of an entire wind farm is performed using a full rotor model for the wind turbines. The analysis scheme combines several technologies, viz. unstructured mesh

  4. Wind Turbine Drivetrain Condition Monitoring - An Overview (Presentation)

    SciTech Connect

    Sheng, S.; Yang, W.

    2013-07-01

    High operation and maintenance costs still hamper the development of the wind industry despite its quick growth worldwide. To reduce unscheduled downtime and avoid catastrophic failures of wind turbines and their components have been and will be crucial to further raise the competitiveness of wind power. Condition monitoring is one of the key tools for achieving such a goal. To enhance the research and development of advanced condition monitoring techniques dedicated to wind turbines, we present an overview of wind turbine condition monitoring, discuss current practices, point out existing challenges, and suggest possible solutions.

  5. NREL Software Aids Offshore Wind Turbine Designs (Fact Sheet)

    SciTech Connect

    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.

  6. Multi-piece wind turbine rotor blades and wind turbines incorporating same

    DOEpatents

    Moroz; Emilian Mieczyslaw (San Diego, CA) [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.

  7. 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…

  8. 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.

  9. Model 0A wind turbine generator FMEA

    NASA Technical Reports Server (NTRS)

    Klein, William E.; Lalli, Vincent R.

    1989-01-01

    The results of Failure Modes and Effects Analysis (FMEA) conducted for the Wind Turbine Generators are presented. The FMEA was performed for the functional modes of each system, subsystem, or component. The single-point failures were eliminated for most of the systems. The blade system was the only exception. The qualitative probability of a blade separating was estimated at level D-remote. Many changes were made to the hardware as a result of this analysis. The most significant change was the addition of the safety system. Operational experience and need to improve machine availability have resulted in subsequent changes to the various systems which are also reflected in this FMEA.

  10. Wind turbine ring/shroud drive system

    DOEpatents

    Blakemore, Ralph W.

    2005-10-04

    A wind turbine capable of driving multiple electric generators having a ring or shroud structure for reducing blade root bending moments, hub loads, blade fastener loads and pitch bearing loads. The shroud may further incorporate a ring gear for driving an electric generator. In one embodiment, the electric generator may be cantilevered from the nacelle such that the gear on the generator drive shaft is contacted by the ring gear of the shroud. The shroud also provides protection for the gearing and aids in preventing gear lubricant contamination.

  11. Turbulence within variable-size wind turbine arrays

    NASA Astrophysics Data System (ADS)

    Chamorro, L. P.; Arndt, R. E. A.; Sotiropoulos, F.

    2014-12-01

    A wind tunnel experiment was performed to study turbulence processes within a model wind turbine array of 3 by 8 model wind turbines of alternating sizes placed aligned with the mean flow. The model wind farm was placed in a boundary layer developed over both smooth and rough surfaces under neutrally stratified conditions. Turbulence statistics, TKE budget terms, and the spectral structure of the turbulence generated within and above the wind farm reveal relevant information about the processes modulating the turbulent energy transfer from the boundary layer to the turbines. The results of the experiment suggest that heterogeneity in turbine size within a wind farm introduce complex flow interactions not seen in a homogeneous farm, and may have positive effects on turbulent loading on the turbines and turbulent exchange with the atmosphere. In general, large scale motions are heavily dampened behind the first row of turbines but a portion of such structures are generated far inside the wind farm, and the scale of the most energetic eddy motions was relatively consistent at different elevations. Overall, the experiment revealed the possibility that heterogeneity of wind turbine size within wind farms have the potential to change the overall potential to harvest energy from the wind, and alter the economics of a project.

  12. Vertical-Axis Wind Turbine Mesh Generator

    SciTech Connect

    2014-01-24

    VAWTGen is a mesh generator for creating a finite element beam mesh of arbitrary vertical-axis wind turbines (VAWT). The software accepts input files specifying tower and blade structural and aerodynamic descriptions and constructs a VAWT using a minimal set of inputs. VAWTs with an arbitrary number of blades can be constructed with or without a central tower. Strut connections between the tower and blades can be specified in an arbitrary manner. The software also facilitates specifying arbitrary joints between structural components and concentrated structural tenns (mass and stiffness). The output files which describe the VAWT configuration are intended to be used with the Offshore Wind ENergy Simulation (OWENS) Toolkit software for structural dynamics analysis of VAWTs. Furthermore, VAWTGen is useful for visualizing output from the OWENS analysis software.

  13. Wind turbine generator with improved operating subassemblies

    DOEpatents

    Cheney, Jr., Marvin C. (24 Stonepost Rd., Glastonbury, CT 06033)

    1985-01-01

    A wind turbine includes a yaw spring return assembly to return the nacelle from a position to which it has been rotated by yawing forces, thus preventing excessive twisting of the power cables and control cables. It also includes negative coning restrainers to limit the bending of the flexible arms of the rotor towards the tower, and stop means on the rotor shaft to orient the blades in a vertical position during periods when the unit is upwind when the wind commences. A pendulum pitch control mechanism is improved by orienting the pivot axis for the pendulum arm at an angle to the longitudinal axis of its support arm, and excessive creep is of the synthetic resin flexible beam support for the blades is prevented by a restraining cable which limits the extent of pivoting of the pendulum during normal operation but which will permit further pivoting under abnormal conditions to cause the rotor to stall.

  14. Wind turbine trailing edge aerodynamic brakes

    SciTech Connect

    Migliore, P G; Miller, L S; Quandt, G A

    1995-04-01

    Five trailing-edge devices were investigated to determine their potential as wind-turbine aerodynamic brakes, and for power modulation and load alleviation. Several promising configurations were identified. A new device, called the spoiler-flap, appears to be the best alternative. It is a simple device that is effective at all angles of attack. It is not structurally intrusive, and it has the potential for small actuating loads. It is shown that simultaneous achievement of a low lift/drag ratio and high drag is the determinant of device effectiveness, and that these attributes must persist up to an angle of attack of 45{degree}. It is also argued that aerodynamic brakes must be designed for a wind speed of at least 45 m/s (100 mph).

  15. Vertical-Axis Wind Turbine Mesh Generator

    Energy Science and Technology Software Center (ESTSC)

    2014-01-24

    VAWTGen is a mesh generator for creating a finite element beam mesh of arbitrary vertical-axis wind turbines (VAWT). The software accepts input files specifying tower and blade structural and aerodynamic descriptions and constructs a VAWT using a minimal set of inputs. VAWTs with an arbitrary number of blades can be constructed with or without a central tower. Strut connections between the tower and blades can be specified in an arbitrary manner. The software also facilitatesmore »specifying arbitrary joints between structural components and concentrated structural tenns (mass and stiffness). The output files which describe the VAWT configuration are intended to be used with the Offshore Wind ENergy Simulation (OWENS) Toolkit software for structural dynamics analysis of VAWTs. Furthermore, VAWTGen is useful for visualizing output from the OWENS analysis software.« less

  16. Wave Models for Offshore Wind Turbines Puneet Agarwal

    E-print Network

    Manuel, Lance

    turbines--onshore or offshore--the prediction of extreme loads as- sociated with a target (long) returnWave Models for Offshore Wind Turbines Puneet Agarwal§ and Lance Manuely Department of Civil well established due to the relative maturity of the industry for onshore wind energy development

  17. Flow Past the Sail Blade of a Wind Turbine

    NASA Astrophysics Data System (ADS)

    Kusaiynov, K.; Kambarova, Zh. T.; Tanasheva, N. K.; Shaimerdenova, K. M.; Alibekova, A. R.

    2015-03-01

    An experiment to determine the aerodynamic characteristics of a wind turbine with sail blades was conducted on a model. The dependence of the drag and lift coefficients on the dimensionless angle of attack and the number of wind-turbine blades has been determined experimentally.

  18. DOE/NREL Advanced Wind Turbine Development Program

    SciTech Connect

    Butterfield, C.P.; Smith, B.; Laxson, A.; Thresher, B.; Goldman, P.

    1993-05-01

    The development of technologically advanced, high-efficiency wind turbines continues to be a high-priority activity of the US wind industry. The National Renewable Energy Laboratory (formerly the Solar Energy Research Institute), sponsored by the US Department of Energy (DOE), has initiated the Advanced Wind Turbine Program to assist the wind industry in the development of a new class of advanced wind turbines. The initial phase of the program focused on developing conceptual designs for near-term and advanced turbines. The goal of the second phase of this program is to use the experience gained over the last decade of turbine design and operation combined with the latest existing design tools to develop a turbine that will produce energy at $0.05 per kilowatt-hour (kWh) in a 5.8-m/s (13-mph) wind site. Three contracts have been awarded, and two more are under negotiation in the second phase. The third phase of the program will use new innovations and state-of-the-art wind turbine design technology to produce a turbine that will generate energy at $0.04/kWh in a 5.8-m/s wind site. Details of the third phase will be announced in early 1993.

  19. RELIABILITY COMPARISON MODELS FOR OFFSHORE WIND TURBINES (OWT)

    E-print Network

    Bernstein, Joseph B.

    RELIABILITY COMPARISON MODELS FOR OFFSHORE WIND TURBINES (OWT) Yizhou Lu, T. M. Delorm, A. Christou components. European Power Electronics and Drives Association (EPE) Journal, 20(4), 2010. 3. OREDA, Offshore of survivor functions R(t) of drive-trains, after 1 year of operation, between Offshore Wind Turbine (OWT) vs

  20. Wind turbine impacts on HF radar ocean surface measurements in

    E-print Network

    Wyatt, Lucy

    . The characterisation of the wind turbine interference is assessed and the radar cross section estimated. The modulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2 Radar Cross Section . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.3 Clutter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.4 The Radar Cross Section of a Wind Turbine . . . . . . . . . . . . . 12 2.5 Noise

  1. DOE/NASA Lewis large wind turbine program

    NASA Technical Reports Server (NTRS)

    Thomas, R. L.

    1982-01-01

    An overview of the large wind turbine activities managed by NASA is given. These activities include resuls from the first and second generation field machines (Mod-0A, -1, and -2), the status of the Department of Interior WTS-4 machine for which NASA is responsible for technical management, and the design phase of the third generation wind turbines (Mod-5).

  2. 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.

  3. 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.

  4. Streamwise development of the wind turbine boundary layer over a model wind turbine array

    NASA Astrophysics Data System (ADS)

    Newman, Jensen; Lebron, Jose; Meneveau, Charles; Castillo, Luciano

    2013-08-01

    The streamwise development of turbulence statistics and mean kinetic energy in a model wind farm consisting of 3 × 5 wind turbines is studied experimentally in a wind tunnel. The analysis uses planar Particle Image Velocimetry data obtained at the centerline plane of the wind farm, covering the inflow as well as four planes in between five downstream wind turbines. The data analysis is organized by dividing these measurement planes into three regions: the above-rotor, rotor-swept, and below-rotor regions. For each field, flow development is quantified using a properly defined relative difference norm based on an integration over each of the regions. Using this norm, it is found that the mean streamwise velocity approaches a fully developed state most rapidly, whereas the flow development is more gradual for the second-order statistics. The vertical entrainment flux of the mean kinetic energy by the Reynolds shear stress, ?U??u'v'?, is observed to develop at a rate similar to that of the Reynolds shear stress rather than the mean streamwise velocity component. Its development is slowest in the layer nearest to the ground. Analysis of various terms in the mean kinetic energy equation shows that the wind turbine boundary layer has not yet reached fully developed conditions by the fifth turbine but that it is approaching such conditions. By comparing the vertical entrainment flux with the horizontal flux due to the mean flow, it is found that the former increases, whereas the latter decreases, as function of downstream distance, but that the former is already an important contributor in the developing region.

  5. Extreme Loads for an Offshore Wind Turbine using Statistical

    E-print Network

    Manuel, Lance

    Extreme Loads for an Offshore Wind Turbine using Statistical Extrapolation from Limited Field Data,itiscommontoeithercarry out extensive simulation studies or undertake a field measurement campaign. At the Blyth offshore wind September 2008 WIND ENERGY Wind Energ. 2008; 11:673­684 Published online 29 October 2008 in Wiley

  6. 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. PMID:25295915

  7. Duration Test Report for the Ventera VT10 Wind Turbine

    SciTech Connect

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

    2013-06-01

    This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small wind turbines. Five turbines were tested at the National Wind Technology Center (NWTC) at the National Renewable Energy Laboratory (NREL) as a part of round one of this project. Duration testing is one of up to five tests that may be performed on the turbines, including power performance, safety and function, noise, and power quality. Test results will provide manufacturers with reports that can be used to fulfill part of the requirements for small wind turbine certification. The test equipment included a grid-connected Ventera Energy Corporation VT10 wind turbine mounted on an 18.3-m (60-ft) self-supporting lattice tower manufactured by Rohn.

  8. 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. PMID:23621051

  9. 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.

  10. Understanding Trends in Wind Turbine Prices Over the Past Decade

    SciTech Connect

    Bolinger, Mark; Wiser, Ryan

    2011-10-26

    Taking a bottom-up approach, this report examines seven primary drivers of wind turbine prices in the United States, with the goal of estimating the degree to which each contributed to the doubling in turbine prices from 2002 through 2008, as well as the subsequent decline in prices through 2010 (our analysis does not extend into 2011 because several of these drivers are best gauged on a full-year basis due to seasonality issues). The first four of these drivers can be considered, at least to some degree, endogenous influences – i.e., those that are largely within the control of the wind industry – and include changes in: 1) Labor costs, which have historically risen during times of tight turbine supply; 2) Warranty provisions, which reflect technology performance and reliability, and are most often capitalized in turbine prices; 3) Turbine manufacturer profitability, which can impact turbine prices independently of costs; and 4) Turbine design, which for the purpose of this analysis is principally manifested through increased turbine size. The other three drivers analyzed in this study can be considered exogenous influences, in that they can impact wind turbine costs but fall mostly outside of the direct control of the wind industry. These exogenous drivers include changes in: 5) Raw materials prices, which affect the cost of inputs to the manufacturing process; 6) Energy prices, which impact the cost of manufacturing and transporting turbines; and 7) Foreign exchange rates, which can impact the dollar amount paid for turbines and components imported into the United States.

  11. An Induction Motor Based Wind Turbine Emulator

    NASA Astrophysics Data System (ADS)

    Sokolovs, A.; Grigans, L.; Kamolins, E.; Voitkans, J.

    2014-04-01

    The authors present a small-scale wind turbine emulator based on the AC drive system and discuss the methods for power coefficient calculation. In the work, the experimental set-up consisting of an AC induction motor, a frequency converter, a synchronous permanent magnet generator, a DC-DC boost converter and DC load was simulated and tested using real-life equipment. The experimentally obtained wind turbine power and torque diagrams using the emulator are in a good agreement with the theoretical ones. Šaj? rakst? par?d?ta mazas jaudas v?ja turb?nas emulatora izveide ar mai?str?vas piedzi?as sist?mu, k? ar? analiz?tas vair?kas turb?nas jaudas koeficienta anal?tisk?s apr??ina metodes. V?ja turb?nas emulatora eksperiment?lais stends, kas sast?v no asinhron? elektromotora, frekven?u p?rveidot?ja, sinhron? past?v?go magn?tu ?eneratora, l?dzstr?vas paaugstinoš? p?rveidot?ja un slodzes, tika p?rbaud?ts gan simul?šanas vid?, gan uz re?l?m iek?rt?m. Eksperiment?li ieg?t?s v?ja turb?nas emulatora jaudas un momenta diagrammas ir sal?dzin?tas ar teor?tiskaj?m.

  12. Wind flow characteristics in the wakes of large wind turbines. Volume I. Analytical model development

    SciTech Connect

    Eberle, W.R.

    1981-09-01

    In order to determine the appropriate spacing between wind turbines, a research program was initiated to characterize the recovery of the wake behind a large wind turbine. The research program had two aspects. The first was the development of an analytical model of wake recovery downwind of the turbine. The analytical model was developed to calculate the wake properties as functions of the downwind coordinate and to generate wind speed profiles (i.e., wind speed as a function of the lateral coordinate for selected altitudes and wind speed as a function of the vertical coordinate) at selected distances downwind of the turbine. The inputs to the model included wind speed, ambient turbulence, and turbine geometric parameters. The second aspect of the program was an experimental program to measure the wake behind the Mod-0A wind turbine at Clayton, New Mexico. The Lockheed laser Doppler velocimeter was used to make the measurements. This volume contains a description of the analytical model development.

  13. CgWind: A high-order accurate simulation tool for wind turbines and wind farms

    SciTech Connect

    Chand, K K; Henshaw, W D; Lundquist, K A; Singer, M A

    2010-02-22

    CgWind is a high-fidelity large eddy simulation (LES) tool designed to meet the modeling needs of wind turbine and wind park engineers. This tool combines several advanced computational technologies in order to model accurately the complex and dynamic nature of wind energy applications. The composite grid approach provides high-quality structured grids for the efficient implementation of high-order accurate discretizations of the incompressible Navier-Stokes equations. Composite grids also provide a natural mechanism for modeling bodies in relative motion and complex geometry. Advanced algorithms such as matrix-free multigrid, compact discretizations and approximate factorization will allow CgWind to perform highly resolved calculations efficiently on a wide class of computing resources. Also in development are nonlinear LES subgrid-scale models required to simulate the many interacting scales present in large wind turbine applications. This paper outlines our approach, the current status of CgWind and future development plans.

  14. 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.

  15. Land Cover and Topography Affect the Land Transformation Caused by Wind Facilities

    PubMed Central

    Diffendorfer, Jay E.; Compton, Roger W.

    2014-01-01

    Land transformation (ha of surface disturbance/MW) associated with wind facilities shows wide variation in its reported values. In addition, no studies have attempted to explain the variation across facilities. We digitized land transformation at 39 wind facilities using high resolution aerial imagery. We then modeled the effects of turbine size, configuration, land cover, and topography on the levels of land transformation at three spatial scales. The scales included strings (turbines with intervening roads only), sites (strings with roads connecting them, buried cables and other infrastructure), and entire facilities (sites and the roads or transmission lines connecting them to existing infrastructure). An information theoretic modeling approach indicated land cover and topography were well-supported variables affecting land transformation, but not turbine size or configuration. Tilled landscapes, despite larger distances between turbines, had lower average land transformation, while facilities in forested landscapes generally had the highest land transformation. At site and string scales, flat topographies had the lowest land transformation, while facilities on mesas had the largest. The results indicate the landscape in which the facilities are placed affects the levels of land transformation associated with wind energy. This creates opportunities for optimizing wind energy production while minimizing land cover change. In addition, the results indicate forecasting the impacts of wind energy on land transformation should include the geographic variables affecting land transformation reported here. PMID:24558449

  16. Land cover and topography affect the land transformation caused by wind facilities.

    PubMed

    Diffendorfer, Jay E; Compton, Roger W

    2014-01-01

    Land transformation (ha of surface disturbance/MW) associated with wind facilities shows wide variation in its reported values. In addition, no studies have attempted to explain the variation across facilities. We digitized land transformation at 39 wind facilities using high resolution aerial imagery. We then modeled the effects of turbine size, configuration, land cover, and topography on the levels of land transformation at three spatial scales. The scales included strings (turbines with intervening roads only), sites (strings with roads connecting them, buried cables and other infrastructure), and entire facilities (sites and the roads or transmission lines connecting them to existing infrastructure). An information theoretic modeling approach indicated land cover and topography were well-supported variables affecting land transformation, but not turbine size or configuration. Tilled landscapes, despite larger distances between turbines, had lower average land transformation, while facilities in forested landscapes generally had the highest land transformation. At site and string scales, flat topographies had the lowest land transformation, while facilities on mesas had the largest. The results indicate the landscape in which the facilities are placed affects the levels of land transformation associated with wind energy. This creates opportunities for optimizing wind energy production while minimizing land cover change. In addition, the results indicate forecasting the impacts of wind energy on land transformation should include the geographic variables affecting land transformation reported here. PMID:24558449

  17. Land cover and topography affect the land transformation caused by wind facilities

    USGS Publications Warehouse

    Diffendorfer, Jay E.; Compton, Roger W.

    2014-01-01

    Land transformation (ha of surface disturbance/MW) associated with wind facilities shows wide variation in its reported values. In addition, no studies have attempted to explain the variation across facilities. We digitized land transformation at 39 wind facilities using high resolution aerial imagery. We then modeled the effects of turbine size, configuration, land cover, and topography on the levels of land transformation at three spatial scales. The scales included strings (turbines with intervening roads only), sites (strings with roads connecting them, buried cables and other infrastructure), and entire facilities (sites and the roads or transmission lines connecting them to existing infrastructure). An information theoretic modeling approach indicated land cover and topography were well-supported variables affecting land transformation, but not turbine size or configuration. Tilled landscapes, despite larger distances between turbines, had lower average land transformation, while facilities in forested landscapes generally had the highest land transformation. At site and string scales, flat topographies had the lowest land transformation, while facilities on mesas had the largest. The results indicate the landscape in which the facilities are placed affects the levels of land transformation associated with wind energy. This creates opportunities for optimizing wind energy production while minimizing land cover change. In addition, the results indicate forecasting the impacts of wind energy on land transformation should include the geographic variables affecting land transformation reported here.

  18. Increasing Wind Turbine Power Generation Through Optimized Flow Control Design

    NASA Astrophysics Data System (ADS)

    Cooney, John; Williams, Theodore; Corke, Thomas

    2013-11-01

    A practical, validated methodology is outlined for implementing flow control systems into wind turbine designs to maximize power generation. This approach involves determining optimal flow control strategies to minimize aerodynamic losses for horizontal axis wind turbines during Region II operation. A quantitative design optimization (QDO) process is completed for the wind turbine utilized in the Notre Dame Laboratory for Enhanced Wind Energy Research. QDO utilizes CFD simulations and shape optimization tools to maximize effectiveness of flow control. Here, only flow control schemes that could be retrofitted on the existing turbine were explored. The final geometry is discussed along with accompanying validations of the predicted performance from wind tunnel experiments at full-scale conditions. Field data from the wind energy laboratory is included.

  19. Wind turbine reliability : a database and analysis approach.

    SciTech Connect

    Linsday, James; Briand, Daniel; Hill, Roger Ray; Stinebaugh, Jennifer A.; Benjamin, Allan S.

    2008-02-01

    The US wind Industry has experienced remarkable growth since the turn of the century. At the same time, the physical size and electrical generation capabilities of wind turbines has also experienced remarkable growth. As the market continues to expand, and as wind generation continues to gain a significant share of the generation portfolio, the reliability of wind turbine technology becomes increasingly important. This report addresses how operations and maintenance costs are related to unreliability - that is the failures experienced by systems and components. Reliability tools are demonstrated, data needed to understand and catalog failure events is described, and practical wind turbine reliability models are illustrated, including preliminary results. This report also presents a continuing process of how to proceed with controlling industry requirements, needs, and expectations related to Reliability, Availability, Maintainability, and Safety. A simply stated goal of this process is to better understand and to improve the operable reliability of wind turbine installations.

  20. Turbine Inflow Characterization at the National Wind Technology Center: Preprint

    SciTech Connect

    Clifton, A.; Schreck, S.; Scott, G.; Kelley, N.; Lundquist, J.

    2012-01-01

    Utility-scale wind turbines operate in dynamic flows that can vary significantly over timescales from less than a second to several years. To better understand the inflow to utility-scale turbines, two inflow towers were installed and commissioned at the National Renewable Energy Laboratory's (NREL) National Wind Technology Center near Boulder, Colorado, in 2011. These towers are 135 m tall and instrumented with a combination of sonic anemometers, cup anemometers, wind vanes, and temperature measurements to characterize the inflow wind speed and direction, turbulence, stability and thermal stratification to two utility-scale turbines. Herein, we present variations in mean and turbulent wind parameters with height, atmospheric stability, and as a function of wind direction that could be important for turbine operation as well as persistence of turbine wakes. Wind speed, turbulence intensity, and dissipation are all factors that affect turbine performance. Our results shown that these all vary with height across the rotor disk, demonstrating the importance of measuring atmospheric conditions that influence wind turbine performance at multiple heights in the rotor disk, rather than relying on extrapolation from lower levels.

  1. Turbine Inflow Characterization at the National Wind Technology Center

    SciTech Connect

    Clifton, A.; Schreck, S.; Scott, G.; Kelley, N.; Lundquist, J. K.

    2012-01-01

    Utility-scale wind turbines operate in dynamic flows that can vary significantly over timescales from less than a second to several years. To better understand the inflow to utility-scale turbines, two inflow towers were installed and commissioned at the National Renewable Energy Laboratory's (NREL) National Wind Technology Center near Boulder, Colorado, in 2011. These towers are 135 m tall and instrumented with a combination of sonic anemometers, cup anemometers, wind vanes, and temperature measurements to characterize the inflow wind speed and direction, turbulence, stability and thermal stratification to two utility-scale turbines. Herein, we present variations in mean and turbulent wind parameters with height, atmospheric stability, and as a function of wind direction that could be important for turbine operation as well as persistence of turbine wakes. Wind speed, turbulence intensity, and dissipation are all factors that affect turbine performance. Our results show that these all vary with height across the rotor disk, demonstrating the importance of measuring atmospheric conditions that influence wind turbine performance at multiple heights in the rotor disk, rather than relying on extrapolation from lower levels.

  2. Wind turbine wake interactions; results from blind tests

    NASA Astrophysics Data System (ADS)

    Krogstad, Per-Åge; Sætran, Lars

    2015-06-01

    Results from three "Blind test" Workshops on wind turbine wake modeling are presented. While the first "Blind test" (BT1, 2011) consisted of a single model turbine located in a large wind tunnel, the complexity was increased for each new test in order to see how various models performed. Thus the next "Blind test" (BT2, 2012) had two turbines mounted in-line. This is a crucial test for models intended to predict turbine performances in a wind farm. In the last "Blind test" (BT3, 2013) the two turbines were again mounted in-line, but offset sideways so that the rotor of the downstream turbine only intersected half the wake from the upstream turbine. This case produces high dynamic loads and strong asymmetry in the wake. For each "Blind test" the turbine geometry and wind tunnel environment was specified and the participants were asked to predict the turbine performances, as well as the wake development to five diameters downstream of the second turbine. For the first two tests axisymmetry could be assumed if the influence of the towers was neglected. This was not possible in BT3 and therefore only fully 3D methods could be applied. In all tests the prediction scatter was surprisingly high.

  3. 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.

  4. 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.

  5. WIND TURBINE DRIVETRAIN TEST FACILITY DATA ACQUISITION SYSTEM

    SciTech Connect

    Mcintosh, J.

    2012-01-03

    The Wind Turbine Drivetrain Test Facility (WTDTF) is a state-of-the-art industrial facility used for testing wind turbine drivetrains and generators. Large power output wind turbines are primarily installed for off-shore wind power generation. The facility includes two test bays: one to accommodate turbine nacelles up to 7.5 MW and one for nacelles up to 15 MW. For each test bay, an independent data acquisition system (DAS) records signals from various sensors required for turbine testing. These signals include resistance temperature devices, current and voltage sensors, bridge/strain gauge transducers, charge amplifiers, and accelerometers. Each WTDTF DAS also interfaces with the drivetrain load applicator control system, electrical grid monitoring system and vibration analysis system.

  6. Duration Test Report for the SWIFT Wind Turbine

    SciTech Connect

    Mendoza, I.; Hur, J.

    2013-01-01

    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. Three turbines where selected for testing at the National Wind Technology Center (NWTC) as a part of round two of the Small Wind Turbine Independent Testing project. Duration testing is one of up to 5 tests that may be performed on the turbines. Other tests include power performance, safety and function, noise, and power quality. The results of the testing will provide the manufacturers with reports that may be used for small wind turbine certification.

  7. Safety and Function Test Report for the SWIFT Wind Turbine

    SciTech Connect

    Mendoza, I.; Hur, J.

    2013-01-01

    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. Three turbines where selected for testing at the National Wind Technology Center (NWTC) as a part of round two of the Small Wind Turbine Independent Testing project. Safety and Function testing is one of up to 5 tests that may be performed on the turbines. Other tests include power performance, duration, noise, and power quality. The results of the testing will provide the manufacturers with reports that may be used for small wind turbine certification.

  8. PHYSICAL REVIEW E 88, 042146 (2013) Uncovering wind turbine properties through two-dimensional stochastic modeling of wind dynamics

    E-print Network

    Peinke, Joachim

    2013-01-01

    PHYSICAL REVIEW E 88, 042146 (2013) Uncovering wind turbine properties through two, such as the rated speed of the wind turbine or the descriptive wind speed statistics, can be related to the equations describing the evolution of power production and wind speed at single wind turbines. DOI: 10

  9. Aalborg Universitet Wind Turbine Control Impact on Stability of Wind Farms Based on Real-Life Systems

    E-print Network

    Bak, Claus Leth

    Aalborg Universitet Wind Turbine Control Impact on Stability of Wind Farms Based on Real version (APA): Kocewiak, L. H., Hjerrild , J., & Bak, C. L. (2012). Wind Turbine Control Impact in frequency domain. The interaction between the wind turbine control system and the wind farm structure

  10. Aeroelastic stability analysis of wind turbines using an eigenvalue approach

    NASA Astrophysics Data System (ADS)

    Hansen, M. H.

    2004-04-01

    A design tool for performing aeroelastic stability analysis of wind turbines is presented in this paper. The method behind this tool is described in a general form, as independent of the particular aeroelastic modelling as possible. Here, the structure is modelled by a Finite beam Element Method, and the aerodynamic loads are modelled by the Blade Element Momentum method coupled with a Beddoes-Leishman type dynamic stall model in a state-space formulation. The linearization of the equations of motion is performed about a steady-state equilibrium, where the deterministic forcing of the turbine is neglected. To eliminate the periodic coefficients and avoid using the Floquet Theory, the multi-blade transformation is utilized. From the corresponding eigenvalue problem, the eigenvalues and eigenvectors can be computed at any operation condition to give the aeroelastic modal properties: Natural frequencies, damping and mode shapes. An example shows a good agreement between predicted and measured aeroelastic damping of a stall-regulated 600 kW turbine. Copyright

  11. H. J. Sutherland, "Fatigue Case Study and Loading Spectra for Wind Turbines," Proceedings of the IEA Third Symposium of Wind Turbine Fatigue, IEA, Implementing

    E-print Network

    1 H. J. Sutherland, "Fatigue Case Study and Loading Spectra for Wind Turbines," Proceedings of the IEA Third Symposium of Wind Turbine Fatigue, IEA, Implementing Agreement for a Programme of Research AND LOADING SPECTRA FOR WIND TURBINES* Herbert J. Sutherland Wind Energy Technology Sandia National

  12. "Comparative Environmental Assessment of Conventional Materials and Wood for the Fabrication of Wind Turbine Blades"

    E-print Network

    Mountziaris, T. J.

    of Wind Turbine Blades" Yashira M. Valentín Feliciano Mentor: Peggi Clouston Graduate Student: Rachel Koh of the turbine blades. Wind turbine blades are commonly made of carbon fiber and fiberglass, which are materials wind energy demands, wood is being evaluated for incorporation into wind turbine blades, since

  13. Design, Analysis, and Learning Control of a Fully Actuated Micro Wind Turbine

    E-print Network

    Kolter, J. Zico

    Design, Analysis, and Learning Control of a Fully Actuated Micro Wind Turbine J. Zico Kolter of renewable energy, and improvements to wind turbine design and control can have a significant impact a actuated micro wind turbine intended for research purposes. While most academic work on wind turbine

  14. An overview of DOE's wind turbine development programs

    NASA Astrophysics Data System (ADS)

    Laxson, A.; Dodge, D.; Flowers, L.; Loose, R.; Goldman, P.

    1993-09-01

    The development of technologically advanced, higher efficiency wind turbines continues to be a high priority activity of the US wind industry. The United States Department of Energy (DOE) is conducting and sponsoring a range of programs aimed at assisting the wind industry with system design, development, and testing. The overall goal is to develop systems that can compete with conventional electric generation for $.05/kWh at 5.8 m/s (13 mph sites) by the mid-1990's and with fossil-fuel-based generators for $.04/kWh at 5.8 m/s sites by the year 2000. These goals will be achieved through several programs. The Value Engineered Turbine Program will promote the rapid development of US capability to manufacture wind turbines with known and well documented records of performance, cost, and reliability, to take advantage of near-term market opportunities. The Advanced Wind Turbine Program will assist US industry to develop and integrate innovative technologies into utility-grade wind turbines for the near-term (mid 1990's) and to develop a new generation of turbines for the year 2000. The collaborative Electric Power Research Institute (EPRI)/DOE Utility Wind Turbine Performance Verification Program will deploy and evaluate commercial-prototype wind turbines in typical utility operating environments, to provide a bridge between development programs currently underway and commercial purchases of utility-grade wind turbines. A number of collaborative efforts also will help develop a range of small systems optimized to work in a diesel hybrid environment to provide electricity for smaller non-grid-connected applications.

  15. Wind turbine rotor hub and teeter joint

    DOEpatents

    Coleman, Clint (Warren, VT); Kurth, William T. (Warren, VT); Jankowski, Joseph (Stowe, VT)

    1994-10-11

    A rotor hub is provided for coupling a wind turbine rotor blade and a shaft. The hub has a yoke with a body which is connected to the shaft, and extension portions which are connected to teeter bearing blocks, each of which has an aperture. The blocks are connected to a saddle which envelops the rotor blade by one or two shafts which pass through the apertures in the bearing blocks. The saddle and blade are separated by a rubber interface which provides for distribution of stress over a larger portion of the blade. Two teeter control mechanisms, which may include hydraulic pistons and springs, are connected to the rotor blade and to the yoke at extension portions. These control mechanisms provide end-of-stroke damping, braking, and stiffness based on the teeter angle and speed of the blade.

  16. Aeroelastic analysis of the Darrieus wind turbine

    SciTech Connect

    Meyer, E.E.

    1982-01-01

    The stability of small oscillations of the troposkein-shaped blade used on Darrieus wind turbines is investigated. The blade is assumed to be attached to a perfectly rigid rotor shaft and spinning in still air. Linear equations of motion are derived which include the effects of inplane, out-of-plane, and torsional stiffness, mass and aerodynamic center offsets, and the aerodynamic wake. Results presented include the free-vibration characteristics of the rotating blade, stability of the blade rotating in air, and the effects of mass density, mass center offset, and stiffness parameters on the flutter rotation rates. All results are presented in dimensionless form, hence apply to a family of blades.

  17. Structural health monitoring of wind turbines

    SciTech Connect

    Simmermacher, T.; James, G.H. III.; Hurtado, J.E.

    1997-09-01

    To properly determine what is needed in a structural health monitoring system, actual operational structures need to be studied. We have found that to effectively monitor the structural condition of an operational structure four areas must be addressed: determination of damage-sensitive parameters, test planning, information condensation, and damage identification techniques. In this work, each of the four areas has been exercised on an operational structure. The structures studied were all be wind turbines of various designs. The experiments are described and lessons learned will be presented. The results of these studies include a broadening of experience in the problems of monitoring actual structures as well as developing a process for implementing such monitoring systems.

  18. Panel resonant behavior of wind turbine blades.

    SciTech Connect

    Paquette, Joshua A.; Griffith, Daniel Todd

    2010-03-01

    The principal design drivers in the certification of wind turbine blades are ultimate strength, fatigue resistance, adequate tip-tower clearance, and buckling resistance. Buckling resistance is typically strongly correlated to both ultimate strength and fatigue resistance. A composite shell with spar caps forms the airfoil shape of a blade and reinforcing shear webs are placed inside the blade to stiffen the blade in the flap-wise direction. The spar caps are dimensioned and the shear webs are placed so as to add stiffness to unsupported panel regions and reduce their length. The panels are not the major flap-wise load carrying element of a blade; however, they must be designed carefully to avoid buckling while minimizing blade weight. Typically, buckling resistance is evaluated by consideration of the load-deflection behavior of a blade using finite element analysis (FEA) or full-scale static testing of blades under a simulated extreme loading condition. The focus of this paper is on the use of experimental modal analysis to measure localized resonances of the blade panels. It can be shown that the resonant behavior of these panels can also provide a means to evaluate buckling resistance by means of analytical or experimental modal analysis. Further, panel resonances have use in structural health monitoring by observing changes in modal parameters associated with panel resonances, and use in improving panel laminate model parameters by correlation with test data. In recent modal testing of wind turbine blades, a set of panel modes were measured. This paper will report on the findings of these tests and accompanying numerical and analytical modeling efforts aimed at investigating the potential uses of panel resonances for blade evaluation, health monitoring, and design.

  19. Aalborg Universitet Methodologies for Wind Turbine and STATCOM Integration in Wind Power Plant

    E-print Network

    Bak, Claus Leth

    Aalborg Universitet Methodologies for Wind Turbine and STATCOM Integration in Wind Power Plant Integration in Wind Power Plant Models for Harmonic Resonances Assessment. In Proceedings of the 14th Wind Integration Workshop: International Workshop on Large-Scale Integration of Wind Power into Power Systems

  20. Modelling of offshore wind turbine wakes with the wind farm program FLaP

    E-print Network

    Heinemann, Detlev

    Modelling of offshore wind turbine wakes with the wind farm program FLaP Bernhard Lange(1) , Hans: Overspeed GmbH, Oldenburg, Germany (3) Risø National Laboratory, Roskilde, Denmark Abstract The wind farm layout program FLaP (Farm Layout Program) estimates the wind speed at any point in a wind farm

  1. 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. PMID:22331894

  2. 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

  3. Locations and attributes of wind turbines in New Mexico, 2009

    USGS Publications Warehouse

    Carr, Natasha B.; Diffendorfer, Jay E.; Fancher, Tammy S.; Latysh, Natalie E.; Leib, Kenneth J.; Matherne, Anne-Marie; Turner, Christine

    2011-01-01

    The New Mexico wind-turbine data series provides geospatial data for all wind turbines established within the State as of August 2009. Attributes specific to each turbine include: turbine location, manufacturer and model, rotor diameter, hub height, rotor height, potential megawatt output, land ownership, and county. 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, year the facility went online, and development status of wind facility. Turbine locations were derived from 1-meter August 2009 true-color aerial photographs produced by the National Agriculture Imagery Program; the photographs have a positional accuracy of about + or - 5 meters. The location of turbines under construction during August 2009 likely will be less accurate than the location of existing turbines. This data series contributes to an Online Interactive Energy Atlas currently (2011) in development by the U.S. Geological Survey. The Energy Atlas will synthesize data on existing and potential energy development in Colorado and New Mexico and will include 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 will be included in the Energy Atlas. The format of the Energy Atlas will facilitate the integration of information about energy with key terrestrial and aquatic resources for evaluating resource values and minimizing risks from energy development.

  4. Locations and attributes of wind turbines in Colorado, 2009

    USGS Publications Warehouse

    Carr, Natasha B.; Diffendorfer, Jay E.; Fancher, Tammy S.; Latysh, Natalie E.; Leib, Kenneth J.; Matherne, Anne-Marie; Turner, Christine

    2011-01-01

    The Colorado wind-turbine data series provides geospatial data for all wind turbines established within the State as of August 2009. Attributes specific to each turbine include: turbine location, manufacturer and model, rotor diameter, hub height, rotor height, potential megawatt output, land ownership, and county. 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, year the facility went online, and development status of wind facility. Turbine locations were derived from August 2009 1-meter true-color aerial photographs produced by the National Agriculture Imagery Program; the photographs have a positional accuracy of about + or - 5 meters. The location of turbines under construction during August 2009 likely will be less accurate than the location of existing turbines. This data series contributes to an Online Interactive Energy Atlas currently (2011) in development by the U.S. Geological Survey. The Energy Atlas will synthesize data on existing and potential energy development in Colorado and New Mexico and will include 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 will be included in the Energy Atlas. The format of the Energy Atlas will facilitate the integration of information about energy with key terrestrial and aquatic resources for evaluating resource values and minimizing risks from energy development.

  5. Fast Verification of Wind Turbine Power Summary of Project Results

    E-print Network

    Fast Verification of Wind Turbine Power Curves: Summary of Project Results by: Cameron Brown ­ s in the FastWind project. Several methods of estimating the power curve uncertainty were developed, it was found to be sensitive to the coherence of high frequency wind speed and power measurements

  6. Evaluation of a wind turbine electric power generator

    NASA Technical Reports Server (NTRS)

    Swim, W. B.

    1981-01-01

    A technical assessment of the aerodynamic performance of the wind wheel turbine (WWT) is reported. The potential of the WWT in utilizing wind as an alternate power source was evaluated. Scaling parameters were developed to predict the aerodynamic performance of WWT prototype sized to produce 3, 9, 30, and 100 kw outputs in a 6.7 m/sec wind.

  7. DOE/NASA wind turbine data acquisition. Part 1: Equipment

    NASA Technical Reports Server (NTRS)

    Strock, O. J.

    1980-01-01

    Large quantities of data were collected, stored, and analyzed in connection with research and development programs on wind turbines. The hardware configuration of the wind energy remote data acquisition system is described along with its use on the NASA/DOE Wind Energy Program.

  8. Mod-5A Wind Turbine Generator Program Design Report. Volume 4: Drawings and Specifications, Book 1

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. Volume 4 contains the drawings and specifications that were developed in preparation for building the MOD-5A wind turbine generator. This is the first of five books of volume four. It contains structural design criteria, generator step-up transformer specs, specs for design, fabrication and testing of the system, specs for the ground control enclosure, systems specs, slip ring specs, and control system specs.

  9. Midwest Consortium for Wind Turbine Reliability and Optimization

    SciTech Connect

    Scott R. Dana; Douglas E. Adams; Noah J. Myrent

    2012-05-11

    This report provides an overview of the efforts aimed to establish a student focused laboratory apparatus that will enhance Purdue's ability to recruit and train students in topics related to the dynamics, operations and economics of wind turbines. The project also aims to facilitate outreach to students at Purdue and in grades K-12 in the State of Indiana by sharing wind turbine operational data. For this project, a portable wind turbine test apparatus was developed and fabricated utilizing an AirX 400W wind energy converter. This turbine and test apparatus was outfitted with an array of sensors used to monitor wind speed, turbine rotor speed, power output and the tower structural dynamics. A major portion of this project included the development of a data logging program used to display real-time sensor data and the recording and creation of output files for data post-processing. The apparatus was tested in an open field to subject the turbine to typical operating conditions and the data acquisition system was adjusted to obtain desired functionality to facilitate use for student projects in existing courses offered at Purdue University and Indiana University. Data collected using the data logging program is analyzed and presented to demonstrate the usefulness of the test apparatus related to wind turbine dynamics and operations.

  10. Wind turbine having a direct-drive drivetrain

    SciTech Connect

    Bevington, Christopher M.; Bywaters, Garrett L.; Coleman, Clint C.; Costin, Daniel P.; Danforth, William L.; Lynch, Jonathan A.; Rolland, Robert H.

    2011-02-22

    A wind turbine comprising an electrical generator that includes a rotor assembly. A wind rotor that includes a wind rotor hub is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle via a bearing assembly. The wind rotor hub includes an opening having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity inside the wind rotor hub. The spindle is attached to a turret supported by a tower. Each of the spindle, turret and tower has an interior cavity that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly.

  11. Wind turbine/generator set and method of making same

    SciTech Connect

    Bevington, Christopher M.; Bywaters, Garrett L.; Coleman, Clint C.; Costin, Daniel P.; Danforth, William L.; Lynch, Jonathan A.; Rolland, Robert H.

    2013-06-04

    A wind turbine comprising an electrical generator that includes a rotor assembly. A wind rotor that includes a wind rotor hub is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle via a bearing assembly. The wind rotor hub includes an opening having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity inside the wind rotor hub. The spindle is attached to a turret supported by a tower. Each of the spindle, turret and tower has an interior cavity that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly.

  12. 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.

  13. Mars Technologies Spawn Durable Wind Turbines

    NASA Technical Reports Server (NTRS)

    Bubenheim, David L.

    2013-01-01

    Sometimes referred to as regenerative life support systems, the concept includes an enclosed self-sufficient habitat that can independently support life for years on end. Such a system aims not only to produce its own food and water but to purify air and convert waste into useful byproducts. In the early 1990s, NASA was planning for an extended stay on Mars, and Bubenheim and his Ames colleagues were concentrating efforts on creating a complete ecological system to sustain human crewmembers during their time on the Red Planet. The main barrier to developing such a system, he says, is energy. Mars has no power plants, and a regenerative system requires equipment that runs on electricity to do everything from regulating humidity in the atmosphere to monitoring the quality of recycled water. The Ames group started looking at how to best make power on a planet that is millions of miles away from Earth and turned to a hybrid concept combining wind and solar power technologies. The reason was that Mars experiences frequent dust storms that can block nearly all sunlight. When theres a dust storm and the wind is blowing, the wind system could be the dominant power source. When the wind is not blowing and the sun is out, photovoltaics could be the dominant source, says Bubenheim.To develop and test the wind power technology, Ames turned to a remote, harsh environment here on Earth: the South Pole. The South Pole was a really good analog for Mars, says Bubenheim. The technology features for going to Mars were the same technology features needed to make something work at the South Pole.Around the same time that NASA started investigating energy technologies for the Red Planet, the National Science Foundation (NSF) was working on a redesign of their station at the South Pole. To power its operations, NSF used fuel that it flew to the remote location, but the Foundation recognized the benefits of also using onsite renewable energy technologies. In the winter they have small crews and their power requirements are less, says Bubenheim. In the summers, they bring in larger groups and photovoltaics could supply a lot of power. Using renewable energy technology could be a way of reducing the amount of fuel they have to fly in.Technology TransferTo advance wind turbine technology to meet the requirements of extremely harsh environments like that on Mars, Ames partnered with NSF and the Department of Energy. It was clear that a lot of the same features were also desirable for the cold regions of the Earth, says Bubenheim. NASA took the leadership on the team because we had the longest-term technology a Mars turbine. Years before, NSF had worked with a company called Northern Power Systems (NPS), based in Barre, Vermont, to deploy a 3-kilowatt wind turbine on Black Island off the coast of Antarctica.Sometimes referred to as regenerative life support systems, the concept includes an enclosed self-sufficient habitat that can independently support life for years on end. Such a system aims not only to produce its own food and water but to purify air and convert waste into useful byproducts. In the early 1990s, NASA was planning for an extended stay on Mars, and Bubenheim and his Ames colleagues were concentrating efforts on creating a complete ecological system to sustain human crewmembers during their time on the Red Planet. The main barrier to developing such a system, he says, is energy. Mars has no power plants, and a regenerative system requires equipment that runs on electricity to do everything from regulating humidity in the atmosphere to monitoring the quality of recycled water. The Ames group started looking at how to best make power on a planet that is millions of miles away from Earth and turned to a hybrid concept combining wind and solar power technologies. The reason was that Mars experiences frequent dust storms that can block nearly all sunlight. When there's a dust storm and the wind is blowing, the wind system could be the dominant power source. When the wind is not blowing and the sun is out, photovoltaics could be the domina

  14. Cost Study for Large Wind Turbine Blades

    SciTech Connect

    ASHWILL, THOMAS D.

    2003-05-01

    The cost study for large wind turbine blades reviewed three blades of 30 meters, 50 meters, and 70 meters in length. Blade extreme wind design loads were estimated in accordance with IEC Class I recommendations. Structural analyses of three blade sizes were performed at representative spanwise stations assuming a stressed shell design approach and E-glass/vinylester laminate. A bill of materials was prepared for each of the three blade sizes using the laminate requirements prepared during the structural analysis effort. The labor requirements were prepared for twelve major manufacturing tasks. TPI Composites developed a conceptual design of the manufacturing facility for each of the three blade sizes, which was used for determining the cost of labor and overhead (capital equipment and facilities). Each of the three potential manufacturing facilities was sized to provide a constant annual rated power production (MW per year) of the blades it produced. The cost of the production tooling and overland transportation was also estimated. The results indicate that as blades get larger, materials become a greater proportion of total cost, while the percentage of labor cost is decreased. Transportation costs decreased as a percentage of total cost. The study also suggests that blade cost reduction efforts should focus on reducing material cost and lowering manufacturing labor, because cost reductions in those areas will have the strongest impact on overall blade cost.

  15. Yaw dynamics of horizontal axis wind turbines

    SciTech Connect

    Hansen, A.C. )

    1992-05-01

    Designers of a horizontal axis wind turbine yaw mechanism are faced with a difficult decision. They know that if they elect to use a yaw- controlled rotor then the system will suffer increased initial cost and increased inherent maintenance and reliability problems. On the other hand, if they elect to allow the rotor to freely yaw they known they will have to account for unknown and random, though bounded, yaw rates. They will have a higher-risk design to trade-off against the potential for cost savings and reliability improvement. The risk of a yaw-free system could be minimized if methods were available for analyzing and understanding yaw behavior. The complexity of yaw behavior has, until recently, discouraged engineers from developing a complete yaw analysis method. The objectives of this work are to (1) provide a fundamental understanding of free-yaw mechanics and the design concepts most effective at eliminating yaw problems, and (2) provide tested design tools and guidelines for use by free-yaw wind systems manufacturers. The emphasis is on developing practical and sufficiently accurate design methods.

  16. 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 fa?ade. 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. PMID:22122963

  17. 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. PMID:24587755

  18. Characterization and Impact of Low Frequency Wind Turbine Noise Emissions

    NASA Astrophysics Data System (ADS)

    Finch, James

    Wind turbine noise is a complex issue that requires due diligence to minimize any potential impact on quality of life. This study enhances existing knowledge of wind turbine noise through focused analyses of downwind sound propagation, directionality, and the low frequency component of the noise. Measurements were conducted at four wind speeds according to a design of experiments at incremental distances and angles. Wind turbine noise is shown to be highly directional, while downwind sound propagation is spherical with limited ground absorption. The noise is found to have a significant low frequency component that is largely independent of wind speed over the 20-250 Hz range. The generated low frequency noise is shown to be audible above 40 Hz at the MOE setback distance of 550 m. Infrasound levels exhibit higher dependency on wind speed, but remain below audible levels up to 15 m/s.

  19. Aeroelastic stability analysis of a Darrieus wind turbine

    SciTech Connect

    Popelka, D.

    1982-02-01

    An aeroelastic stability analysis has been developed for predicting flutter instabilities on vertical axis wind turbines. The analytical model and mathematical formulation of the problem are described as well as the physical mechanism that creates flutter in Darrieus turbines. Theoretical results are compared with measured experimental data from flutter tests of the Sandia 2 Meter turbine. Based on this comparison, the analysis appears to be an adequate design evaluation tool.

  20. Investigation of Various Wind Turbine Drivetrain Condition Monitoring Techniques (Presentation)

    SciTech Connect

    Sheng, S.

    2011-08-01

    This presentation was given at the 2011 Wind Turbine Reliability Workshop sponsored by Sandia National Laboratories in Albuquerque, NM on August 2-3, 2011. It discusses work for the Gearbox Reliability Collaborative including downtime caused by turbine subsystems, annual failure frequency of turbine subsystems, cost benefits of condition monitoring (CM), the Gearbox Reliability Collaborative's condition monitoring approach and rationale, test setup, and results and observations.

  1. Mod-2 wind turbine system development. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The development of the MOD-2 wind turbine through acceptance testing and initial operational evaluation is documented. Pitch control hydraulic system, yaw control system, drive train, electrical power station, control system, operations and maintenance experience, and availability are discussed.

  2. Washington University Can the Sound Generated by Modern Wind Turbines

    E-print Network

    Salt, Alec N.

    Living Nearby? Alec N. Salt, Ph.D. Department of OtolaryngologyDepartment of Otolaryngology Washington 64 66 68 70 Sound Exposure (dBA) %HighlyAnnoyed Wind Turbines Aircraft Railway Road Traffic Adapted

  3. Large Wind Turbine Design Characteristics and R and D Requirements

    NASA Technical Reports Server (NTRS)

    Lieblein, S. (editor)

    1979-01-01

    Detailed technical presentations on large wind turbine research and development activities sponsored by public and private organizations are presented. Both horizontal and vertical axis machines are considered with emphasis on their structural design.

  4. Variable speed generator technology options for wind turbine generators

    NASA Astrophysics Data System (ADS)

    Lipo, T. A.

    1995-05-01

    The electrical system options for variable speed operation of a wind turbine generator are treated in this paper. The key operating characteristics of each system are discussed and the major advantages and disadvantages of each are identified

  5. Variable speed generator technology options for wind turbine generators

    NASA Technical Reports Server (NTRS)

    Lipo, T. A.

    1995-01-01

    The electrical system options for variable speed operation of a wind turbine generator are treated in this paper. The key operating characteristics of each system are discussed and the major advantages and disadvantages of each are identified

  6. SMART Wind Turbine Rotor: Design and Field Test

    SciTech Connect

    Berg, Jonathan C.; Resor, Brian R.; Paquette, Joshua A.; White, Jonathan R.

    2014-01-29

    This report documents the design, fabrication, and testing of the SMART Rotor. This work established hypothetical approaches for integrating active aerodynamic devices (AADs) into the wind turbine structure and controllers.

  7. Superconducting generators for large off shore wind turbines 

    E-print Network

    Keysan, Ozan

    2014-06-30

    This thesis describes four novel superconducting machine concepts, in the pursuit of finding a suitable design for large offshore wind turbines. The designs should be reliable, modular and light-weight. The main novelty ...

  8. Vertical axis wind turbine with continuous blade angle adjustment

    E-print Network

    Weiss, Samuel Bruce

    2010-01-01

    The author presents a concept for a vertical axis wind turbine that utilizes each blade's entire rotational cycle for power generation. Each blade has its own vertical axis of rotation and is constrained to rotate at the ...

  9. Design of wind turbines with Ultra-High Performance Concrete

    E-print Network

    Jammes, François-Xavier

    2009-01-01

    Ultra-High Performance Concrete (UHPC) has proven an asset for bridge design as it significantly reduces costs. However, UHPC has not been applied yet to wind turbine technology. Design codes do not propose any recommendations ...

  10. An experimental investigation on the characteristics of fluidstructure interactions of a wind turbine model sited

    E-print Network

    Hu, Hui

    turbine model sited in microburst-like winds Yan Zhang, Partha P. Sarkar, Hui Hu n Department of Aerospace: Received 6 December 2014 Accepted 23 June 2015 Keywords: Wind turbine aeromechanics Microburst-like wind the characteristics of the fluid­ structure interactions and microburst-induced wind loads acting on a wind turbine

  11. Wind Turbine Lightning Protection Project: 1999-2001

    SciTech Connect

    McNiff, B.

    2002-05-01

    A lightning protection research and support program was instituted by NREL to help minimize lightning damage to wind turbines in the United States. This paper provides the results of a field test program, an evaluation of protection on selected turbines, and a literature search as well as the dissemination of the accumulated information.

  12. DOE/SNL-TTU scaled wind farm technology facility : research opportunities for study of turbine-turbine interaction.

    SciTech Connect

    Barone, Matthew Franklin; White, Jonathan

    2011-09-01

    The proposed DOE/Sandia Scaled Wind Farm Technology Facility (SWiFT) hosted by Texas Tech University at Reese Technology Center in Lubbock, TX, will provide a facility for experimental study of turbine-turbine interaction and complex wind farm aerodynamics. This document surveys the current status of wind turbine wake and turbine-turbine interaction research, identifying knowledge and data gaps that the proposed test site can potentially fill. A number of turbine layouts is proposed, allowing for up to ten turbines at the site.

  13. 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.

  14. Operational behavior of a double-fed permanent magnet generator for wind turbines

    E-print Network

    Reddy, Sivananda Kumjula

    2005-01-01

    Greater efficiency in wind turbine systems is achieved by allowing the rotor to change its rate of rotation as the wind speed changes. The wind turbine system is decoupled from the utility grid and a variable speed operation ...

  15. Atmospheric and Wake Turbulence Impacts on Wind Turbine Fatigue Loadings

    SciTech Connect

    Lee, S.; Churchfield, M.; Moriarty, P.; Jonkman, J.; Michalakes, J.

    2012-01-01

    Large-eddy simulations of atmospheric boundary layers under various stability and surface roughness conditions are performed to investigate the turbulence impact on wind turbines. In particular, the aeroelastic responses of the turbines are studied to characterize the fatigue loading of the turbulence present in the boundary layer and in the wake of the turbines. Two utility-scale 5-MW turbines that are separated by seven rotor diameters are placed in a 3 km by 3 km by 1 km domain. They are subjected to atmospheric turbulent boundary layer flow and data is collected on the structural response of the turbine components. The surface roughness was found to increase the fatigue loads while the atmospheric instability had a small influence. Furthermore, the downstream turbines yielded higher fatigue loads indicating that the turbulent wakes generated from the upstream turbines have significant impact.

  16. Sutherland, Wind Energy 2002, ASME/AIAA AIAA-2002-0065 INFLOW AND THE FATIGUE OF THE LIST WIND TURBINE*

    E-print Network

    Sutherland, Wind Energy 2002, ASME/AIAA AIAA-2002-0065 1 INFLOW AND THE FATIGUE OF THE LIST WIND TURBINE* Herbert J. Sutherland Wind Energy Technology Department Sandia National Laboratory Albuquerque on wind turbines. A heavily instrumented Micon 65/13M turbine with SERI 8m blades is being used

  17. Multivariate analysis and prediction of wind turbine response to varying wind field characteristics based on machine learning

    E-print Network

    Stanford University

    Multivariate analysis and prediction of wind turbine response to varying wind field characteristics characteristics have a significant impact on the structural response and the lifespan of wind turbines. This paper presents a machine learning approach towards analyzing and predicting the response of wind turbine

  18. Estimation Of Wind Resources And Fatigue Analysis Of A Wind Turbine Rotor Using Wind Data Statistics

    NASA Astrophysics Data System (ADS)

    Mahri, Zine Labidine; Rouabah, Mohamed Salah; Zid, Said

    2010-11-01

    In this work a statistical analysis of wind speed is carried out, using meteorological data, in order to estimate wind characteristics in different regions of Algeria and accordingly determine the most efficient sites. The probability density curve of wind speed can provide useful information about the wind variation such as average and mean speed; it can also be helpful for the estimation of extreme wind occurrence. All these gathered pieces of information can be used efficiently to make a good decision about the wind site selection and to achieve an optimal design of a wind turbine, being energetically efficient and structurally sound. The wind statistical distribution, for a given site, can be also useful in fatigue calculation since it can determine the number of cycles completed, at different wind speed ranges, during the lifetime of the turbine. In the second part of this work, dynamic stresses are computed for the root region of the blades, using finite element modelling. This region is a highly loaded and structurally complex area. The resulting curves of dynamic stresses (stress vs. time), obtained for different wind speeds, are used along with the statistical data (analysed previously) to perform fatigue analysis in order to make an optimal design of the rotor.

  19. Wind turbines for electric utilities: Development status and economics

    NASA Technical Reports Server (NTRS)

    Ramler, J. R.; Donovan, R. M.

    1979-01-01

    The technology and economics of the large, horizontal-axis wind turbines currently in the Federal Wind Energy Program are presented. Wind turbine technology advancements made in the last several years are discussed. It is shown that, based on current projections of the costs of these machines when produced in quantity, they should be attractive for utility application. The cost of electricity (COE) produced at the busbar is shown to be a strong function of the mean wind speed at the installation site. The breakeven COE as a fuel saver is discussed and the COE range that would be generally attractive to utilities is indicated.

  20. Wind turbine acoustics research bibliography with selected annotation

    NASA Technical Reports Server (NTRS)

    Hubbard, Harvey H.; Shepherd, Kevin P.

    1988-01-01

    Citations of documents are included, which represent the state-of-the-art of technology in each of the following acoustics subject areas: Prediction of Wind Turbine Noise; Acoustic Measurements for Wind Tunnels; Effect of Wind Turbine Noise on Building Structures, People and Communities; Atmospheric Propagation; and Measurement Technology Including Wind Screens. Documents are listed in chronological order in each section of the paper, with key documents and associated annotation listed first. The sources are given along with acquisition numbers, when available, to expedite the acquisition of copies of the documents.

  1. Low frequency acoustic emissions from large horizontal axis wind turbines

    NASA Technical Reports Server (NTRS)

    Hubbard, Harvey H.; Shepherd, Kevin P.

    1989-01-01

    Available test data and theoretical predictions of LF noise from large wind turbines of the type to be used for energy generation are briefly summarized. The main LF noise sources are identified as tower-wake/blade interactions and rotor-plane inflow gradients. Sound-pressure time histories, measured and calculated narrow-band and rotational noise spectra, and noise radiation patterns for the WTS-4 and WWG-0600 wind turbines are presented graphically.

  2. High temperature co-axial winding transformers

    NASA Technical Reports Server (NTRS)

    Divan, Deepakraj M.; Novotny, Donald W.

    1993-01-01

    The analysis and design of co-axial winding transformers is presented. The design equations are derived and the different design approaches are discussed. One of the most important features of co-axial winding transformers is the fact that the leakage inductance is well controlled and can be made low. This is not the case in conventional winding transformers. In addition, the power density of co-axial winding transformers is higher than conventional ones. Hence, using co-axial winding transformers in a certain converter topology improves the power density of the converter. The design methodology used in meeting the proposed specifications of the co-axial winding transformer specifications are presented and discussed. The final transformer design was constructed in the lab. Co-axial winding transformers proved to be a good choice for high power density and high frequency applications. They have a more predictable performance compared with conventional transformers. In addition, the leakage inductance of the transformer can be controlled easily to suit a specific application. For space applications, one major concern is the extraction of heat from power apparatus to prevent excessive heating and hence damaging of these units. Because of the vacuum environment, the only way to extract heat is by using a cold plate. One advantage of co-axial winding transformers is that the surface area available to extract heat from is very large compared to conventional transformers. This stems from the unique structure of the co-axial transformer where the whole core surface area is exposed and can be utilized for cooling effectively. This is a crucial issue here since most of the losses are core losses.

  3. The role of turbulent mixing in wind turbine wake recovery and wind array performance

    NASA Astrophysics Data System (ADS)

    Fruh, Wolf-Gerrit; Creech, Angus; Maguire, Eoghan

    2014-05-01

    The effect of wind turbine wakes in large offshore wind energy arrays can be a substantial factor in affecting the performance of turbines inside the array. Turbulent mixing plays a key role in the wake recovery, having a significant effect on the length over which the wake is strong enough to affect the performance other turbines significantly. We aim to highlight how turbulence affects wind turbine wakes, first by examining a high resolution CFD model of a single turbine wake validated by LIDAR measurements [1], and secondly with a much larger CFD simulation of Lillgrund offshore wind farm, validated with SCADA data [2]. By comparing the decay rates behind single turbines in environments of different surrounding surface features, ranging from ideal free-slip wind tunnels to mixed-vegetation hills, we suggest that the decay rate of turbine wakes are enhanced by free-stream turbulence, created by topography and ground features. In the context of Lillgrund wind farm, observations and computational results suggest that the wakes created by the turbines in the leading row facing the wind decay much slower than those in second row, or further into the turbine array. This observation can be explained by the diffusive action of upwind turbulence breaking up the wake generated by a turbine rotor. Angus CW Creech, Wolf-Gerrit Früh, Peter Clive (2012). Actuator volumes and hradaptive methods for threedimensional simulation of wind turbine wakes and performance. Wind Energy Vol.15, 847 - 863. Angus C.W. Creech, Wolf-Gerrit Früh, A. Eoghan Maguire (2013). High-resolution CFD modelling of Lillgrund Wind farm. Renewable Energies and Power Quality Journal, Vol. 11

  4. Wind turbine blade damage detection using an active sensing approach

    NASA Astrophysics Data System (ADS)

    Ruan, Jiabiao; Ho, Siu Chun Michael; Patil, Devendra; Li, Mo; Song, Gangbing

    2014-10-01

    The wind energy sector is one of the fastest growing parts of the clean energy industry. As the wind energy sector grows, so does an increasing concern for the damage detection of wind turbine blades. This paper proposes an active sensing approach by utilizing piezoceramic transducers as actuators and sensors. The influence of the crack quantity, location, length and depth on the wave propagation was experimentally studied. Sweep sine signals ranging from 1 khz to 50 khz were used as input signals for active sensing. The change in the energy that propagated through the cracks was verified as feasible in detecting crack-related damage. An innovative polar plot analysis method based on Fast Fourier transform was developed to compare the minuscule difference between the damage signals and the baseline signal. The polar plot was able to make apparent differences in both the magnitude and the phase of the signals, which could be correlated to crack depth and plane geometry, respectively, based on the observation of the damage.

  5. 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.

  6. Method and apparatus for wind turbine air gap control

    DOEpatents

    Grant, James Jonathan; Bagepalli, Bharat Sampathkumaran; Jansen, Patrick Lee; DiMascio, Paul Stephen; Gadre, Aniruddha Dattatraya; Qu, Ronghai

    2007-02-20

    Methods and apparatus for assembling a wind turbine generator are provided. The wind turbine generator includes a core and a plurality of stator windings circumferentially spaced about a generator longitudinal axis, a rotor rotatable about the generator longitudinal axis wherein the rotor includes a plurality of magnetic elements coupled to a radially outer periphery of the rotor such that an airgap is defined between the stator windings and the magnetic elements and the plurality of magnetic elements including a radially inner periphery having a first diameter. The wind turbine generator also includes a bearing including a first member in rotatable engagement with a radially inner second member, the first member including a radially outer periphery, a diameter of the radially outer periphery of the first member being substantially equal to the first diameter, the rotor coupled to the stator through the bearing such that a substantially uniform airgap is maintained.

  7. Simulation of wind turbine wakes using the actuator line technique.

    PubMed

    Sørensen, Jens N; Mikkelsen, Robert F; Henningson, Dan S; Ivanell, Stefan; Sarmast, Sasan; Andersen, Søren J

    2015-02-28

    The actuator line technique was introduced as a numerical tool to be employed in combination with large eddy simulations to enable the study of wakes and wake interaction in wind farms. The technique is today largely used for studying basic features of wakes as well as for making performance predictions of wind farms. In this paper, we give a short introduction to the wake problem and the actuator line methodology and present a study in which the technique is employed to determine the near-wake properties of wind turbines. The presented results include a comparison of experimental results of the wake characteristics of the flow around a three-bladed model wind turbine, the development of a simple analytical formula for determining the near-wake length behind a wind turbine and a detailed investigation of wake structures based on proper orthogonal decomposition analysis of numerically generated snapshots of the wake. PMID:25583862

  8. IEA R&D Wind Annex XI Symposium on Wind Turbine Fatigue

    E-print Network

    IEA R&D Wind Annex XI Symposium on Wind Turbine Fatigue DLR, Stuttgart February 1-2, 1996 DAMAGE ESTIMATES FOR EUROPEAN AND U.S. SITES USING THE U.S. HIGH-CYCLE FATIGUE DATA BASE Herbert J. Sutherland Wind for typical U.S. blade materials and one for European materials, to analyze the service lifetime of a wind

  9. Advanced Wind Turbine Program Next Generation Turbine Development Project: June 17, 1997--April 30, 2005

    SciTech Connect

    GE Wind Energy, LLC

    2006-05-01

    This document reports the technical results of the Next Generation Turbine Development Project conducted by GE Wind Energy LLC. This project is jointly funded by GE and the U.S. Department of Energy's National Renewable Energy Laboratory.The goal of this project is for DOE to assist the U.S. wind industry in exploring new concepts and applications of cutting-edge technology in pursuit of the specific objective of developing a wind turbine that can generate electricity at a levelized cost of energy of $0.025/kWh at sites with an average wind speed of 15 mph (at 10 m height).

  10. Proposed Wind Turbine Aeroelasticity Studies Using Helicopter Systems Analysis

    NASA Technical Reports Server (NTRS)

    Ladkany, Samaan G.

    1998-01-01

    Advanced systems for the analysis of rotary wing aeroelastic structures (helicopters) are being developed at NASA Ames by the Rotorcraft Aeromechanics Branch, ARA. The research has recently been extended to the study of wind turbines, used for electric power generation Wind turbines play an important role in Europe, Japan & many other countries because they are non polluting & use a renewable source of energy. European countries such as Holland, Norway & France have been the world leaders in the design & manufacture of wind turbines due to their historical experience of several centuries, in building complex wind mill structures, which were used in water pumping, grain grinding & for lumbering. Fossil fuel cost in Japan & in Europe is two to three times higher than in the USA due to very high import taxes. High fuel cost combined with substantial governmental subsidies, allow wind generated power to be competitive with the more traditional sources of power generation. In the USA, the use of wind energy has been limited mainly because power production from wind is twice as expensive as from other traditional sources. Studies conducted at the National Renewable Energy Laboratories (NREL) indicate that the main cost in the production of wind turbines is due to the materials & the labor intensive processes used in the construction of turbine structures. Thus, for the US to assume world leadership in wind power generation, new lightweight & consequently very flexible wind turbines, that could be economically mass produced, would have to be developed [4,5]. This effort, if successful, would result in great benefit to the US & the developing nations that suffer from overpopulation & a very high cost of energy.

  11. Coupled Dynamic Modeling of Floating Wind Turbine Systems: Preprint

    SciTech Connect

    Wayman, E. N.; Sclavounos, P. D.; Butterfield, S.; Jonkman, J.; Musial, W.

    2006-03-01

    This article presents a collaborative research program that the Massachusetts Institute of Technology (MIT) and the National Renewable Energy Laboratory (NREL) have undertaken to develop innovative and cost-effective floating and mooring systems for offshore wind turbines in water depths of 10-200 m. Methods for the coupled structural, hydrodynamic, and aerodynamic analysis of floating wind turbine systems are presented in the frequency domain. This analysis was conducted by coupling the aerodynamics and structural dynamics code FAST [4] developed at NREL with the wave load and response simulation code WAMIT (Wave Analysis at MIT) [15] developed at MIT. Analysis tools were developed to consider coupled interactions between the wind turbine and the floating system. These include the gyroscopic loads of the wind turbine rotor on the tower and floater, the aerodynamic damping introduced by the wind turbine rotor, the hydrodynamic damping introduced by wave-body interactions, and the hydrodynamic forces caused by wave excitation. Analyses were conducted for two floater concepts coupled with the NREL 5-MW Offshore Baseline wind turbine in water depths of 10-200 m: the MIT/NREL Shallow Drafted Barge (SDB) and the MIT/NREL Tension Leg Platform (TLP). These concepts were chosen to represent two different methods of achieving stability to identify differences in performance and cost of the different stability methods. The static and dynamic analyses of these structures evaluate the systems' responses to wave excitation at a range of frequencies, the systems' natural frequencies, and the standard deviations of the systems' motions in each degree of freedom in various wind and wave environments. This article in various wind and wave environments. This article explores the effects of coupling the wind turbine with the floating platform, the effects of water depth, and the effects of wind speed on the systems' performance. An economic feasibility analysis of the two concepts was also performed. Key cost components included the material and construction costs of the buoy; material and installation costs of the tethers, mooring lines, and anchor technologies; costs of transporting and installing the system at the chosen site; and the cost of mounting the wind turbine to the platform. The two systems were evaluated based on their static and dynamic performance and the total system installed cost. Both systems demonstrated acceptable motions, and have estimated costs of $1.4-$1.8 million, not including the cost of the wind turbine, the power electronics, or the electrical transmission.

  12. Advanced wind turbine design studies: Advanced conceptual study. Final report

    SciTech Connect

    Hughes, P.; Sherwin, R.

    1994-08-01

    In conjunction with the US Department of Energy and the National Renewable Energy Laboratory`s Advanced Wind Turbine Program, the Atlantic Orient Corporation developed preliminary designs for the next generation of wind turbines. These 50 kW and 350 kW turbines are based upon the concept of simplicity. By adhering to a design philosophy that emphasizes simplicity, we project that these turbines will produce energy at extremely competitive rates which will unlock the potential of wind energy domestically and internationally. The program consisted of three distinct phases. First, we evaluated the operational history of the Enertech 44 series wind turbines. As a result of this evaluation, we developed, in the second phase, a preliminary design for a new 50 kW turbine for the near-term market. In the third phase, we took a clean-sheet-of-paper approach to designing a 350 kW turbine focused on the mid-1990s utility market that incorporated past experience and advanced technology.

  13. Advanced wind turbine design studies: Advanced conceptual study

    NASA Astrophysics Data System (ADS)

    Hughes, P.; Sherwin, R.

    1994-08-01

    In conjunction with the US Department of Energy and the National Renewable Energy Laboratory's Advanced Wind Turbine Program, the Atlantic Orient Corporation developed preliminary designs for the next generation of wind turbines. These 50 kW and 350 kW turbines are based upon the concept of simplicity. By adhering to a design philosophy that emphasizes simplicity, we project that these turbines will produce energy at extremely competitive rates which will unlock the potential of wind energy domestically and internationally. The program consisted of three distinct phases. First, we evaluated the operational history of the Enertech 44 series wind turbines. As a result of this evaluation, we developed, in the second phase, a preliminary design for a new 50 kW turbine for the near-term market. In the third phase, we took a clean-sheet-of-paper approach to designing a 350 kW turbine focused on the mid-1990s utility market that incorporated past experience and advanced technology.

  14. 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.

  15. Advanced Issues of Wind Turbine Modelling and Control

    NASA Astrophysics Data System (ADS)

    Simani, Silvio

    2015-11-01

    The motivation for this paper comes from a real need to have an overview about the challenges of modelling and control for very demanding systems, such as wind turbine systems, which require reliability, availability, maintainability, and safety over power conversion efficiency. These issues have begun to stimulate research and development in the wide control community particularly for these installations that need a high degree of “sustainability”. Note that this topic represents a key point mainly for offshore wind turbines with very large rotors, since they are characterised by challenging modelling and control problems, as well as expensive and safety critical maintenance works. In this case, a clear conflict exists between ensuring a high degree of availability and reducing maintenance times, which affect the final energy cost. On the other hand, wind turbines have highly nonlinear dynamics, with a stochastic and uncontrollable driving force as input in the form of wind speed, thus representing an interesting challenge also from the modelling point of view. Suitable control methods can provide a sustainable optimisation of the energy conversion efficiency over wider than normally expected working conditions. Moreover, a proper mathematical description of the wind turbine system should be able to capture the complete behaviour of the process under monitoring, thus providing an important impact on the control design itself. In this way, the control scheme could guarantee prescribed performance, whilst also giving a degree of “tolerance” to possible deviation of characteristic properties or system parameters from standard conditions, if properly included in the wind turbine model itself. The most important developments in advanced controllers for wind turbines are addressed, and open problems in the areas of modelling of wind turbines are also outlined.

  16. Nonlinear parametric instability of wind turbine wings

    NASA Astrophysics Data System (ADS)

    Larsen, J. W.; Nielsen, S. R. K.

    2007-01-01

    Nonlinear rotor dynamic is characterized by parametric excitation of both linear and nonlinear terms caused by centrifugal and Coriolis forces when formulated in a moving frame of reference. Assuming harmonically varying support point motions from the tower, the nonlinear parametric instability of a wind turbine wing has been analysed based on a two-degrees-of-freedom model with one modal coordinate representing the vibrations in the blade direction and the other vibrations in edgewise direction. The functional basis for the eigenmode expansion has been taken as the linear undamped fixed-base eigenmodes. It turns out that the system becomes unstable at certain excitation amplitudes and frequencies. If the ratio between the support point motion and the rotational frequency of the rotor is rational, the response becomes periodic, and Floquet theory may be used to determine instability. In reality the indicated frequency ratio may be irrational in which case the response is shown to be quasi-periodic, rendering the Floquet theory useless. Moreover, as the excitation frequency exceeds the eigenfrequency in the edgewise direction, the response may become chaotic. For this reason stability of the system has in all cases been evaluated based on a Lyapunov exponent approach. Stability boundaries are determined as a function of the amplitude and frequency of the support point motion, the rotational speed, damping ratios and eigenfrequencies in the blade and edgewise directions.

  17. Monitoring system of wind turbine rotor blades

    NASA Astrophysics Data System (ADS)

    Frankenstein, B.; Schubert, L.; Meyendorf, N.; Friedmann, H.; Ebert, C.

    2009-03-01

    Conventionally, modal monitoring of Wind Turbine Rotor Blades is primarily based on the evaluation of eigenfrequencies. Beyond this, combining a sensor network with the Operational Modal Analysis (OMA) method, mode shape and parallely a local component are utilized here. In addition it is expected that the damping, which is also determined by the OMA method, will give a lead on damage development at the rotor already at an early stage. Modal monitoring by means of measurement is combined with FEM simulation and with the comparison of results obtained from measurement and simulation. Moreover, this will establish a connection between the engineer and the design data of a rotor blade, which also are based on FEM analyzes. A further significant increase regarding error resolution is possible by combining the global modal methods with locally sensitive monitoring methods, based on guided elastic waves. These assume plate-like structures through which elastic waves propagate in the low-frequency ultrasonic range (10 - 100 kHz) in certain modes. These different wave modes interact distinctively with inner structural damages such as web fractures and delaminations. It is differentiated between piezoelectrically excited waves (acousto ultrasonics), and waves produced by energy released at fractures, delamination etc. (acoustic emission). Applying a moderate number of sensors, the combination of both methods can allow an effective monitoring of the global structure.

  18. a Mathematical Model for Wind Turbine Blades

    NASA Astrophysics Data System (ADS)

    BAUMGART, A.

    2002-03-01

    A mathematical model for an elastic wind turbine blade mounted on a rigid test stand is derived and compared with experimental results. The linear equations of motion describe small rotations of the test stand, blade lateral deflections and rotation of the chord. Warping, extension and tilt of the cross-sections are slaved to the dependent minimal co-ordinates in order to reduce the number of state variables. Using the principle of virtual work, a procedure is employed which combines the volume discretization of general “solid”, or shell-type finite elements (FE), with the approach of global form functions (stretching over the whole blade length). The equations of motion are solved as an eigenvalue problem and the results are compared with an experimental modal analysis of a 19 m long blade. The computed eigenfrequencies fit well, but the mathematical model underestimates the pitch motion of the blade chord. Parameter studies show the effect of warping. Despite the few degrees of freedom and uncertainties in the model parameters, the mathematical model approximates the measured blade dynamics well.

  19. Wind Turbine Blade Design System - Aerodynamic and Structural Analysis

    NASA Astrophysics Data System (ADS)

    Dey, Soumitr

    2011-12-01

    The ever increasing need for energy and the depletion of non-renewable energy resources has led to more advancement in the "Green Energy" field, including wind energy. An improvement in performance of a Wind Turbine will enhance its economic viability, which can be achieved by better aerodynamic designs. In the present study, a design system that has been under development for gas turbine turbomachinery has been modified for designing wind turbine blades. This is a very different approach for wind turbine blade design, but will allow it to benefit from the features inherent in the geometry flexibility and broad design space of the presented system. It starts with key overall design parameters and a low-fidelity model that is used to create the initial geometry parameters. The low-fidelity system includes the axisymmetric solver with loss models, T-Axi (Turbomachinery-AXIsymmetric), MISES blade-to-blade solver and 2D wing analysis code XFLR5. The geometry parameters are used to define sections along the span of the blade and connected to the CAD model of the wind turbine blade through CAPRI (Computational Analysis PRogramming Interface), a CAD neutral API that facilitates the use of parametric geometry definition with CAD. Either the sections or the CAD geometry is then available for CFD and Finite Element Analysis. The GE 1.5sle MW wind turbine and NERL NASA Phase VI wind turbine have been used as test cases. Details of the design system application are described, and the resulting wind turbine geometry and conditions are compared to the published results of the GE and NREL wind turbines. A 2D wing analysis code XFLR5, is used for to compare results from 2D analysis to blade-to-blade analysis and the 3D CFD analysis. This kind of comparison concludes that, from hub to 25% of the span blade to blade effects or the cascade effect has to be considered, from 25% to 75%, the blade acts as a 2d wing and from 75% to the tip 3D and tip effects have to be taken into account for design considerations. In addition, the benefits of this approach for wind turbine design and future efforts are discussed.

  20. WindPACT Turbine Design Scaling Studies Technical Area 2: Turbine, Rotor and Blade Logistics

    SciTech Connect

    Smith, K.

    2001-07-16

    Through the National Renewable Energy Laboratory (NREL), the United States Department of Energy (DOE) implemented the Wind Partnership for Advanced Component Technologies (WindPACT) program. This program will explore advanced technologies that may reduce the cost of energy (COE) from wind turbines. The initial step in the WindPACT program is a series of preliminary scaling studies intended to determine the optimum sizes for future turbines, help define sizing limits for certain critical technologies, and explore the potential for advanced technologies to contribute to reduced COE as turbine scales increase. This report documents the results of Technical Area 2-Turbine Rotor and Blade Logistics. For this report, we investigated the transportation, assembly, and crane logistics and costs associated with installation of a range of multi-megawatt-scale wind turbines. We focused on using currently available equipment, assembly techniques, and transportation system capabilities and limitations to hypothetically transport and install 50 wind turbines at a facility in south-central South Dakota.

  1. Characterizing wind turbine system response to lightning activity

    SciTech Connect

    McNiff, B.; LaWhite, N.; Muljadi, E.

    1998-07-01

    A lightning protection research program was instituted by National Renewable Energy Laboratory to minimize lightning damage to wind turbines and to further the understanding of effective damage mitigation techniques. To that end, a test program is under way to observe lightning activity, protection system response, and damage at a wind power plant in the Department of Energy (DOE) and Electric Power Research Institute (EPRI) Turbine Verification Program. The authors installed Lightning activated surveillance cameras along with a special storm tracking device to observe the activity in the wind plant area. They instrumented the turbines with lightning and ground current detection devices to log direct and indirect strike activity at each unit. They installed a surge monitor on the utility interface to track incoming activity from the transmission lines. Maintenance logs are used to verify damage and determine downtime and repair costs. Actual strikes to turbines were recorded on video and ancillary devices. The test setup and some results are discussed in this paper.

  2. 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.)

  3. Causes of bat fatalities at wind turbines: Hypotheses and predictions

    USGS Publications Warehouse

    Cryan, P.M.; Barclay, R.M.R.

    2009-01-01

    Thousands of industrial-scale wind turbines are being built across the world each year to meet the growing demand for sustainable energy. Bats of certain species are dying at wind turbines in unprecedented numbers. Species of bats consistently affected by turbines tend to be those that rely on trees as roosts and most migrate long distances. Although considerable progress has been made in recent years toward better understanding the problem, the causes of bat fatalities at turbines remain unclear. In this synthesis, we review hypothesized causes of bat fatalities at turbines. Hypotheses of cause fall into 2 general categoriesproximate and ultimate. Proximate causes explain the direct means by which bats die at turbines and include collision with towers and rotating blades, and barotrauma. Ultimate causes explain why bats come close to turbines and include 3 general types: random collisions, coincidental collisions, and collisions that result from attraction of bats to turbines. The random collision hypothesis posits that interactions between bats and turbines are random events and that fatalities are representative of the bats present at a site. Coincidental hypotheses posit that certain aspects of bat distribution or behavior put them at risk of collision and include aggregation during migration and seasonal increases in flight activity associated with feeding or mating. A surprising number of attraction hypotheses suggest that bats might be attracted to turbines out of curiosity, misperception, or as potential feeding, roosting, flocking, and mating opportunities. Identifying, prioritizing, and testing hypothesized causes of bat collisions with wind turbines are vital steps toward developing practical solutions to the problem. ?? 2009 American Society of Mammalogists.

  4. Health effects and wind turbines: A review of the literature

    PubMed Central

    2011-01-01

    Background Wind power has been harnessed as a source of power around the world. Debate is ongoing with respect to the relationship between reported health effects and wind turbines, specifically in terms of audible and inaudible noise. As a result, minimum setback distances have been established world-wide to reduce or avoid potential complaints from, or potential effects to, people living in proximity to wind turbines. People interested in this debate turn to two sources of information to make informed decisions: scientific peer-reviewed studies published in scientific journals and the popular literature and internet. Methods The purpose of this paper is to review the peer-reviewed scientific literature, government agency reports, and the most prominent information found in the popular literature. Combinations of key words were entered into the Thomson Reuters Web of KnowledgeSM and the internet search engine Google. The review was conducted in the spirit of the evaluation process outlined in the Cochrane Handbook for Systematic Reviews of Interventions. Results Conclusions of the peer reviewed literature differ in some ways from those in the popular literature. In peer reviewed studies, wind turbine annoyance has been statistically associated with wind turbine noise, but found to be more strongly related to visual impact, attitude to wind turbines and sensitivity to noise. To date, no peer reviewed articles demonstrate a direct causal link between people living in proximity to modern wind turbines, the noise they emit and resulting physiological health effects. If anything, reported health effects are likely attributed to a number of environmental stressors that result in an annoyed/stressed state in a segment of the population. In the popular literature, self-reported health outcomes are related to distance from turbines and the claim is made that infrasound is the causative factor for the reported effects, even though sound pressure levels are not measured. Conclusions What both types of studies have in common is the conclusion that wind turbines can be a source of annoyance for some people. The difference between both types is the reason for annoyance. While it is acknowledged that noise from wind turbines can be annoying to some and associated with some reported health effects (e.g., sleep disturbance), especially when found at sound pressure levels greater than 40 db(A), given that annoyance appears to be more strongly related to visual cues and attitude than to noise itself, self reported health effects of people living near wind turbines are more likely attributed to physical manifestation from an annoyed state than from wind turbines themselves. In other words, it appears that it is the change in the environment that is associated with reported health effects and not a turbine-specific variable like audible noise or infrasound. Regardless of its cause, a certain level of annoyance in a population can be expected (as with any number of projects that change the local environment) and the acceptable level is a policy decision to be made by elected officials and their government representatives where the benefits of wind power are weighted against their cons. Assessing the effects of wind turbines on human health is an emerging field and conducting further research into the effects of wind turbines (and environmental changes) on human health, emotional and physical, is warranted. PMID:21914211

  5. Dynamic Simulation of DFIG Wind Turbines on FPGA Boards

    E-print Network

    Zambreno, Joseph A.

    and rotor resistances; Ls and L~ are the stator and rotor inductances; t.; is the magnetizing inductance and the mechanical power Pm extracted from the wind [10]. The pertinent equations are Pm == ~P1fR~Cp(A,(3)V~ (7) Cp + 1 where p is the air density; Rw is the wind turbine radius; cp (A, (3) is the performance

  6. Power fluctuations smoothing and regulations in wind turbine generator systems

    NASA Astrophysics Data System (ADS)

    Babazadehrokni, Hamed

    Wind is one of the most popular renewable energy sources and it has the potential to become the biggest energy source in future. Since the wind does not always blow constantly, the output wind power is not constant which may make some problem for the power grid. According to the grid code which is set by independent system operator, ISO, wind turbine generator systems need to follow some standards such as the predetermined acceptable power fluctuations. In order to smooth the output powers, the energy storage system and some power electronics modules are employed. The utilized power electronics modules in the wind turbine system can pursue many different goals, such as maintaining the voltage stability, frequency stability, providing the available and predetermined output active and reactive power. On the other side, the energy storage system can help achieving some of these goals but its main job is to store the extra energy when not needed and release the stored energy when needed. The energy storage system can be designed in different sizes, material and also combination of different energy storage systems (hybrid designs). Combination of power electronics devises and also energy storage system helps the wind turbine systems to smooth the output power according to the provided standards. In addition prediction of wind speed may improve the performance of wind turbine generator systems. In this research study all these three topics are studied and the obtained results are written in 10 papers which 7 of them are published and three of them are under process.

  7. Modelling of a chaotic load of wind turbines drivetrain

    NASA Astrophysics Data System (ADS)

    Bielecki, Andrzej; Barszcz, Tomasz; Wójcik, Mateusz

    2015-03-01

    The purpose of this paper is to present a model of the load of the wind turbine gears for simulation of real, varying operational conditions for modelling of wind turbine vibration. The characteristics of the wind, which generates chaotically varying loads on the drivetrain components generating load in teeth and bearings of gears during torque transfer, are discussed. A generator of variable load of wind turbines drivetrain is proposed. Firstly, the module for generation of wind speed is designed. It is based on the approach in which the wind speed was considered as a time series approximated by the Weierstrass function. Secondly, the rotational speed of the main shaft is proposed as a function of the wind speed value. The function depends on a few parameters that are fitted by using a genetic algorithm. Finally, the model of torque of the main shaft is introduced. This model has been created by using a multi-layer artificial neural network. The results show that the proposed approach yields a very good fit for the experimental data. The fit brings about the proper reproducing of all the aspects of the load that are crucial for causing fatigue and, as a consequence, damaging of gears of the wind turbines.

  8. Review of Wind Turbine Wake Models and Future Directions (Presentation)

    SciTech Connect

    Churchfield, M. J.

    2013-08-01

    This presentation gives a brief overview to wind turbine wake modeling, ranging from models used in the 1980s up to the present. The presentation shows the strengths and weaknesses of various models and discusses the needs of the wind energy industry and research sectors. Both power production and loads analysis are discussed.

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

    NASA Astrophysics Data System (ADS)

    Nikoli?, Vlastimir; Petkovi?, Dalibor; Por, Lip Yee; Shamshirband, Shahaboddin; Zamani, Mazdak; ?ojbaši?, 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.

  10. Analytical expressions for maximum wind turbine average power in a Rayleigh wind regime

    SciTech Connect

    Carlin, P.W.

    1996-12-01

    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 considered 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.

  11. Measurements of Operational Wind Turbine Noise in UK Waters.

    PubMed

    Cheesman, Samuel

    2016-01-01

    The effects of wind farm operational noise have not been addressed to the same extent as their construction methods such as piling and drilling of the foundations despite their long operational lifetimes compared with weeks of construction. The results of five postconstruction underwater sound-monitoring surveys on wind farms located throughout the waters of the British Isles are discussed. These wind farms consist of differing turbine power outputs, from 3 to 3.6 MW, and differing numbers of turbines. This work presents an overview of the results obtained and discusses both the levels and frequency components of the sound in several metrics. PMID:26610955

  12. Fuzzy Regulator Design for Wind Turbine Yaw Control

    PubMed Central

    Koulouras, Grigorios

    2014-01-01

    This paper proposes the development of an advanced fuzzy logic controller which aims to perform intelligent automatic control of the yaw movement of wind turbines. The specific fuzzy controller takes into account both the wind velocity and the acceptable yaw error correlation in order to achieve maximum performance efficacy. In this way, the proposed yaw control system is remarkably adaptive to the existing conditions. In this way, the wind turbine is enabled to retain its power output close to its nominal value and at the same time preserve its yaw system from pointless movement. Thorough simulation tests evaluate the proposed system effectiveness. PMID:24693237

  13. Damage tolerance and structural monitoring for wind turbine blades.

    PubMed

    McGugan, M; Pereira, G; Sørensen, B F; Toftegaard, H; Branner, K

    2015-02-28

    The paper proposes a methodology for reliable design and maintenance of wind turbine rotor blades using a condition monitoring approach and a damage tolerance index coupling the material and structure. By improving the understanding of material properties that control damage propagation it will be possible to combine damage tolerant structural design, monitoring systems, inspection techniques and modelling to manage the life cycle of the structures. This will allow an efficient operation of the wind turbine in terms of load alleviation, limited maintenance and repair leading to a more effective exploitation of offshore wind. PMID:25583858

  14. Fuzzy regulator design for wind turbine yaw control.

    PubMed

    Theodoropoulos, Stefanos; Kandris, Dionisis; Samarakou, Maria; Koulouras, Grigorios

    2014-01-01

    This paper proposes the development of an advanced fuzzy logic controller which aims to perform intelligent automatic control of the yaw movement of wind turbines. The specific fuzzy controller takes into account both the wind velocity and the acceptable yaw error correlation in order to achieve maximum performance efficacy. In this way, the proposed yaw control system is remarkably adaptive to the existing conditions. In this way, the wind turbine is enabled to retain its power output close to its nominal value and at the same time preserve its yaw system from pointless movement. Thorough simulation tests evaluate the proposed system effectiveness. PMID:24693237

  15. PERFORMANCE ENHANCEMENT OF WIND TURBINE POWER REGULATION BY SWITCHED LINEAR CONTROL

    E-print Network

    Duffy, Ken

    PERFORMANCE ENHANCEMENT OF WIND TURBINE POWER REGULATION BY SWITCHED LINEAR CONTROL D.J.Leith W Power regulation of horizontal-axis grid-connected up-wind constant-speed pitch-regulated wind turbines ENHANCEMENT OF WIND TURBINE POWER REGULATION BY SWITCHED LINEAR CONTROL D.J.Leith W.E.Leithead Department

  16. An assessment of the economic impact of the wind turbine supply chain in Illinois

    SciTech Connect

    Carlson, J. Lon; Loomis, David G.; Payne, James

    2010-08-15

    The enormous growth of wind energy in Illinois and around the country has led to a shortage of wind turbines. Turbine manufacturers have sold out their capacity into 2010. To the extent that Illinois manufacturing can integrate itself into the wind turbine supply chain, Illinois can enjoy the economic benefits from both having wind farms and supplying the parts to build them. (author)

  17. Hardware-in-the-Loop Simulations and Control Design for a Small Vertical Axis Wind Turbine

    E-print Network

    Yanikoglu, Berrin

    Hardware-in-the-Loop Simulations and Control Design for a Small Vertical Axis Wind Turbine Ugur a maximum power point tracking (MPPT) algorithm for small vertical axis wind turbines (VAWTs). Wind torque tracking; vertical axis wind turbine, inertia emulation; disturbance torque compensation I. INTRODUCTION

  18. A Summary of the Fatigue Properties of Wind Turbine Materials

    SciTech Connect

    SUTHERLAND, HERBERT J.

    1999-10-07

    Modern wind turbines are fatigue critical machines that are typically used to produce electrical power from the wind. The materials used to construct these machines are subjected to a unique loading spectrum that contains several orders of magnitude more cycles than other fatigue critical structures, e.g., an airplane. To facilitate fatigue designs, a large database of material properties has been generated over the past several years that is specialized to materials typically used in wind turbines. In this paper, I review these fatigue data. Major sections are devoted to the properties developed for wood, metals (primarily aluminum) and fiberglass. Special emphasis is placed on the fiberglass discussion because this material is current the material of choice for wind turbine blades. The paper focuses on the data developed in the U.S., but cites European references that provide important insights.

  19. Fatigue case study and loading spectra for wind turbines

    NASA Astrophysics Data System (ADS)

    Sutherland, H. J.

    The paper discusses two aspects of Sandia's Wind Energy Program. The first section of the paper presents a case study of fatigue in wind turbines. This case study was prepared for the American Society of Testing Material's (ASTM) Standard Technical Publication (STP) on fatigue education. Using the LIFE2 code, the student is lead through the process of cumulative damage summation for wind turbines and typical data are used to demonstrate the range of life estimates that will result from typical parameter variations. The second section summarizes the results from a workshop held by Sandia and the National Renewable Energy Laboratory (NREL) to discuss fatigue life prediction methodologies. This section summarizes the workshop discussions on the use of statistical modeling to deduce the shape and magnitude of the low-probability-of-occurrence, high-stress tail of the load distribution on a wind turbine during normal operation.

  20. Application of Damage Detection Techniques Using Wind Turbine Modal Data

    SciTech Connect

    Gross, E.; Rumsey, M.; Simmermacher, T.; Zadoks, R.I.

    1998-12-17

    As any structure ages, its structural characteristics will also change. The goal of this work was to determine if modal response data fkom a wind turbine could be used in the detection of damage. The input stimuli to the wind turbine were from traditional modal hammer input and natural wind excitation. The structural response data was acquired using accelerometers mounted on the rotor of a parked and undamaged horizontal-axis wind turbine. The bolts at the root of one of the three blades were then loosened to simulate a damaged blade. The structural response data of the rotor was again recorded. The undamaged and damage-simulated datasets were compared using existing darnage detection algorithms. Also, a novel algorithm for combining the results of different damage detection algorithms was utilized in the assessment of the data. This paper summarizes the code development and discusses some preliminary damage detection results.

  1. 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

    ...Vestas Nacelles America, Inc. (Wind Turbine Nacelles, Hubs, Blades and Towers...special-purpose subzone at the wind turbine nacelle, hub, blade and tower manufacturing...manufacturing and warehousing of wind turbine nacelles, hubs, blades and towers...

  2. Larger Turbines and the Future Cost of Wind Energy (Poster)

    SciTech Connect

    Lantz, E.; Hand, M.

    2011-03-01

    The move to larger turbines has been observed in the United States and around the world. Turbine scaling increases energy capture while reducing general project infrastructure costs and landscape impacts, each of which of can reduce the cost of wind energy. However, scaling in the absence of innovation, can increase turbine costs. The ability of turbine designers and manufacturers to continue to scale turbines, while simultaneously reducing costs, is an important factor in long-term viability of the industry. This research seeks to better understand how technology innovation can allow the continued development of larger turbines on taller towers while also achieving lower cost of energy. Modeling incremental technology improvements identified over the past decade demonstrates that cost reductions on the order of 10%, and capacity factor improvements on the order of 5% (for sites with annual mean wind speed of 7.25 m/s at 50m), are achievable for turbines up to 3.5 MW. However, to achieve a 10% cost reduction and a 10% capacity factor improvement for turbines up to 5 MW, additional technology innovations must be developed and implemented.

  3. CFD Simulations on Interference Effects between Offshore Wind Turbines

    NASA Astrophysics Data System (ADS)

    Weihing, P.; Meister, K.; Schulz, C.; Lutz, Th; Krämer, E.

    2014-06-01

    This paper presents results of detailed 3D CFD simulations of two 5MW wind turbines sited in the German wind farm Alpha Ventus which are located behind each other at half-wake conditions. The focus of interest in this study is put on wake - turbine interaction, in order to derive the main shadow effects and their influence on blade loads and power response of the downstream turbine. For this purpose, Detached Eddy Simulations (DES) were performed using the flow solver FLOWer from DLR (German Aerospace Center). To consider all relevant aerodynamic effects, the main turbine components are represented as direct model with resolved boundary layers. Measurement-based turbulent inflow conditions are prescribed to realistically account for the atmospheric boundary layer. In order to analyze the flow conditions in front of the downstream turbine, wake propagation and velocity spectra are evaluated and compared with the undisturbed atmospheric boundary layer. Their impact on loads and power production and their corresponding fluctuations is discussed by comparing these with the upstream turbine. It was found, that fatigue loads occurring at half-wake conditions are significantly higher for the downstream turbine, since blade load fluctuations are highly amplified by the unsteady wake of the upstream turbine.

  4. Alstom 3-MW Wind Turbine Installed at NWTC (Fact Sheet)

    SciTech Connect

    Not Available

    2011-09-01

    The 3-MW Alstom wind turbine was installed at NREL's NWTC in October 2010. Test data will be used to validate advanced turbine design and analysis tools. NREL signed a Cooperative Research and Development Agreement with Alstom in 2010 to conduct certification testing on the company's 3-MW ECO 100 wind turbine and to validate models of Alstom's unique drivetrain concept. The turbine was installed at NREL's National Wind Technology Center (NWTC) in October 2010 and engineers began certification testing in 2011. Tests to be conducted by NREL include a power quality test to finalize the International Electrotechnical Commission (IEC) requirements for type certification of the 60-Hz unit. The successful outcome of this test will enable Alstom to begin commercial production of ECO 100 in the United States. NREL also will obtain additional measurements of power performance, acoustic noise, and system frequency to complement the 50 Hz results previously completed in Europe. After NREL completes the certification testing on the ECO 100, it will conduct long-term testing to validate gearbox performance to gain a better understanding of the machine's unique ALSTOM PURE TORQUE{trademark} drivetrain concept. In conventional wind turbines, the rotor is supported by the shaft-bearing gearbox assembly. Rotor loads are partially transmitted to the gearbox and may reduce gearbox reliability. In the ALSTOM PURE TORQUE concept, the rotor is supported by a cast frame running through the hub, which transfers bending loads directly to the tower. Torque is transmitted to the shaft through an elastic coupling at the front of the hub. According to Alstom, this system will increase wind turbine reliability and reduce operation and maintenance costs by isolating the gearbox from rotor loads. Gearbox reliability has challenged the wind energy industry for more than two decades. Gearbox failures require expensive and time-consuming replacement, significantly increasing the cost of wind plant operation while reducing the plant's power output and revenue. To solve gearbox reliability issues, NREL launched a Gearbox Reliability Collaborative (GRC) in 2006 and brought together the world's leading turbine manufacturers, consultants, and experts from more than 30 companies and organizations. GRC's goal was to validate the typical design process-from wind turbine system loads to bearing ratings-through a comprehensive dynamometer and field-test program. Design analyses will form a basis for improving reliability of future designs and retrofit packages. Through its study of Alstom's Eco 100 gearbox, NREL can compare its GRC model gearbox with Alstom's and add the results to the GRC database, which is helping to advance more reliable wind turbine technology.

  5. Methods and apparatus for cooling wind turbine generators

    DOEpatents

    Salamah, Samir A. (Niskayuna, NY); Gadre, Aniruddha Dattatraya (Rexford, NY); Garg, Jivtesh (Schenectady, NY); Bagepalli, Bharat Sampathkumaran (Niskayuna, NY); Jansen, Patrick Lee (Alplaus, NY); Carl, Jr., Ralph James (Clifton Park, NY)

    2008-10-28

    A wind turbine generator includes a stator having a core and a plurality of stator windings circumferentially spaced about a generator longitudinal axis. A rotor is rotatable about the generator longitudinal axis, and the rotor includes a plurality of magnetic elements coupled to the rotor and cooperating with the stator windings. The magnetic elements are configured to generate a magnetic field and the stator windings are configured to interact with the magnetic field to generate a voltage in the stator windings. A heat pipe assembly thermally engaging one of the stator and the rotor to dissipate heat generated in the stator or rotor.

  6. Development of large, horizontal-axis wind turbines

    NASA Technical Reports Server (NTRS)

    Baldwin, D. H.; Kennard, J.

    1985-01-01

    A program to develop large, horizontal-axis wind turbines is discussed. The program is directed toward developing the technology for safe, reliable, environmentally acceptable large wind turbines that can generate a significant amount of electricity at costs competitive with those of conventional electricity-generating systems. In addition, these large wind turbines must be fully compatible with electric utility operations and interface requirements. Several ongoing projects in large-wind-turbine development are directed toward meeting the technology requirements for utility applications. The machines based on first-generation technology (Mod-OA and Mod-1) successfully completed their planned periods of experimental operation in June, 1982. The second-generation machines (Mod-2) are in operation at selected utility sites. A third-generation machine (Mod-5) is under contract. Erection and initial operation of the Mod-5 in Hawaii should take place in 1986. Each successive generation of technology increased reliability and energy capture while reducing the cost of electricity. These advances are being made by gaining a better understanding of the system-design drivers, improving the analytical design tools, verifying design methods with operating field data, and incorporating new technology and innovative designs. Information is given on the results from the first- and second-generation machines (Mod-OA, - 1, and -2), the status of the Department of Interior, and the status of the third-generation wind turbine (Mod-5).

  7. Characterization of a wind turbine model for wake aerodynamics studies

    NASA Astrophysics Data System (ADS)

    Cuzzola, Francesco; Aubrun, Sandrine; Leitl, Bernd

    2014-12-01

    A model wind turbine has been designed at the University of Hamburg within the scope of the FP7 fundend project WAUDIT. The purpose of the experiment described in this paper is to characterize the performances of two rotors by means of measuring the thrust coefficient Ct. Ct is a similarity parameter for the wake and is thought to be the most effective one. Its value has been directly measured using a force balance and indirectly calculated from the velocity profiles measured three diameters downstream of the rotor with hot wire anemometry. Results show that, in order to reproduce the wake behaviour, the matching of the Ct, which is a quantitative achievement, has to be integrated with measurements such as velocity profiles in the wake. In fact the velocity deficit illustrates the mechanism of transforming the axial momentum into torque assuring qualitatively the proper reproduction of the wake. This latter information assures that the achievement of a certain thrust force acting on the rotor is due to its performances in transforming the axial momentum into torque and not an effect of other phenomena such as a stall at the blades.

  8. Optimizing small wind turbine performance in battery charging applications

    NASA Astrophysics Data System (ADS)

    Drouilhet, Stephen; Muljadi, Eduard; Holz, Richard; Gevorgian, Vahan

    1995-05-01

    Many small wind turbine generators (10 kW or less) consist of a variable speed rotor driving a permanent magnet synchronous generator (alternator). One application of such wind turbines is battery charging, in which the generator is connected through a rectifier to a battery bank. The wind turbine electrical interface is essentially the same whether the turbine is part of a remote power supply for telecommunications, a standalone residential power system, or a hybrid village power system, in short, any system in which the wind generator output is rectified and fed into a DC bus. Field experience with such applications has shown that both the peak power output and the total energy capture of the wind turbine often fall short of expectations based on rotor size and generator rating. In this paper, the authors present a simple analytical model of the typical wind generator battery charging system that allows one to calculate actual power curves if the generator and rotor properties are known. The model clearly illustrates how the load characteristics affect the generator output. In the second part of this paper, the authors present four approaches to maximizing energy capture from wind turbines in battery charging applications. The first of these is to determine the optimal battery bank voltage for a given WTG. The second consists of adding capacitors in series with the generator. The third approach is to place an optimizing DC/DC voltage converter between the rectifier and the battery bank. The fourth is a combination of the series capacitors and the optimizing voltage controller. They also discuss both the limitations and the potential performance gain associated with each of the four configurations.

  9. Effects of incoming wind condition and wind turbine aerodynamics on the hub vortex instability

    NASA Astrophysics Data System (ADS)

    Ashton, R.; Viola, F.; Gallaire, F.; Iungo, G. V.

    2015-06-01

    Dynamics and instabilities occurring in the near-wake of wind turbines have a crucial role for the wake downstream evolution, and for the onset of far-wake instabilities. Furthermore, wake dynamics significantly affect the intra-wind farm wake flow, wake interactions and potential power losses. Therefore, the physical understanding and predictability of wind turbine wake instabilities become a nodal point for prediction of wind power harvesting and optimization of wind farm layout. This study is focused on the prediction of the hub vortex instability encountered within wind turbine wakes under different operational conditions of the wind turbine. Linear stability analysis of the wake flow is performed by means of a novel approach that enables to take effects of turbulence on wake instabilities into account. Stability analysis is performed by using as base flow the time-averaged wake velocity field at a specific downstream location. The latter is modeled through Carton-McWilliams velocity profiles by mimicking the presence of the hub vortex and helicoidal tip vortices, and matching the wind turbine thrust coefficient predicted through the actuator disc model. The results show that hub vortex instability is promoted by increasing the turbine thrust coefficient. Indeed, a larger aerodynamic load produces an enhanced wake velocity deficit and axial shear, which are considered the main sources for the wake instability. Nonetheless, wake swirl also promotes hub vortex instability, and it can also affect the azimuthal wavenumber of the most unstable mode.

  10. The Wake of a Single Vertical Axis Wind Turbine

    NASA Astrophysics Data System (ADS)

    Barsky, Danielle

    Vertical axis wind turbines (VAWTs) pose various advantages over traditional horizontal axis wind turbines (HAWTs), including their smaller size and footprint, quiet operation, and ability to produce power under a greater variety of wind directions and wind speeds. To determine the optimal spacing of an array of VAWTs for maximum power output, an understanding of the fundamental wake structure of a single VAWT is needed. This study is among the first attempts to experimentally visualize the wake of a VAWT using stereo particle image velocimetry (PIV). A scale VAWT is placed inside a wind tunnel and a motor rotates the scale model at a constant rotational speed. Wake data at several Reynolds numbers and tip speed ratios indicate that vortices are shed by each blade of the spinning VAWT, demonstrating significant differences between the wake of a VAWT and a spinning cylinder.

  11. Wind Turbine Wake Experiment - Wieringermeer (WINTWEX-W)

    NASA Astrophysics Data System (ADS)

    Kumer, Valerie; Reuder, Joachim; Svardal, Benny; Eecen, Peter

    2014-05-01

    The Wind Turbine Wake Experiment - Wieringermeer (WINTWEX-W) is a cooperative wake measurement campaign conducted by the Norwegian Centre of Offshore Wind Energy (Norcowe) and the Energy Research Centre of the Netherlands (ECN). A scanning, four static Windcubes as well as a downstream looking nacelle LiDAR are placed for half a year downstream of one of five research wind turbines in ECNs' wind turbine test farm Wieringermeer. In order to capture wake characteristics under different weather conditions a 60° sector for three different elevations and two vertical cross-sections are scanned every minute with additional wind profile information every second at 2, 5 and 12 rotor diameter distances. Another static Windcube, a forward-looking nacelle LiDAR and three Sonics are placed upstream to measure the undisturbed approaching flow field. During the campaign several scanning algorithms are tested to capture most wake features. The aim of the campaign is a qualitative and quantitative description of single wind turbine wake evolution, propagation and persistency, as well as to improve CFD wake models by delivering a detailed data set of several real atmospheric conditions.

  12. Comparison of financing costs for wind turbine and fossil powerplants

    SciTech Connect

    Kahn, E.

    1995-02-01

    This paper compares the financing costs of wind turbine powerplants with those of fossil powerplants. The goal of this examination is to determine the extent to which these costs differ and what the sources of such differences may be. The discussion is organized in the following fashion. Section 2 introduces basic terminology and concepts from finance, as they apply in the powerplant setting. Section 3 reviews available data from a variety of sources to estimate the magnitude of the variables identified in Section 2. In Section 4 we examine the effect of the production tax credit enacted in the Energy Policy Act of 1992 on the financing of wind turbine projects. Conclusions are offered in Section 5. In the past two years there have been only two wind turbine projects that have been financed, so the basis for broad conclusions is limited. Nonetheless, there appears to be a significant advantage in financing costs for conventional projects compared to wind turbines. The two sources of disadvantage to wind power are first, the cost of equity capital is significantly more expensive, and second, the capital structure of wind projects has a much greater fraction of expensive equity than conventional alternatives.

  13. SHM of wind turbine blades using piezoelectric active-sensors

    SciTech Connect

    Park, Gyuhae; Taylor, Stuart G; Farinholt, Kevin M; Farrar, Charles R

    2010-01-01

    This paper presents a variety of structural health monitoring (SHM) techniques, based on the use of piezoelectric active-sensors, used to determine the structural integrity of wind turbine blades. Specifically, Lamb wave propagations, frequency response functions, and time series based methods are utilized to estimate the condition of wind turbine blades. For experiments, a 1m section of a 9m CX100 blade is used. Overall, these three methods yielded a sufficient damage detection capability to warrant further investigation into field deployment. A full-scale fatigue test of a CX-100 wind turbine blade is also conducted. This paper summarizes considerations needed to design such SHM systems, experimental procedures and results, and practical implementation issues that can be used as guidelines for future investigations.

  14. Quiet airfoils for small and large wind turbines

    DOEpatents

    Tangler, James L. (Boulder, CO); Somers, Dan L. (Port Matilda, PA)

    2012-06-12

    Thick airfoil families with desirable aerodynamic performance with minimal airfoil induced noise. The airfoil families are suitable for a variety of wind turbine designs and are particularly well-suited for use with horizontal axis wind turbines (HAWTs) with constant or variable speed using pitch and/or stall control. In exemplary embodiments, a first family of three thick airfoils is provided for use with small wind turbines and second family of three thick airfoils is provided for use with very large machines, e.g., an airfoil defined for each of three blade radial stations or blade portions defined along the length of a blade. Each of the families is designed to provide a high maximum lift coefficient or high lift, to exhibit docile stalls, to be relatively insensitive to roughness, and to achieve a low profile drag.

  15. Adaptive pitch control for variable speed wind turbines

    DOEpatents

    Johnson, Kathryn E. (Boulder, CO); Fingersh, Lee Jay (Westminster, CO)

    2012-05-08

    An adaptive method for adjusting blade pitch angle, and controllers implementing such a method, for achieving higher power coefficients. Average power coefficients are determined for first and second periods of operation for the wind turbine. When the average power coefficient for the second time period is larger than for the first, a pitch increment, which may be generated based on the power coefficients, is added (or the sign is retained) to the nominal pitch angle value for the wind turbine. When the average power coefficient for the second time period is less than for the first, the pitch increment is subtracted (or the sign is changed). A control signal is generated based on the adapted pitch angle value and sent to blade pitch actuators that act to change the pitch angle of the wind turbine to the new or modified pitch angle setting, and this process is iteratively performed.

  16. Compliance effects on dynamically pitching wind turbine airfoils

    NASA Astrophysics Data System (ADS)

    Magstadt, Andrew S.

    The effects of elastic compliance in dynamically pitching wind turbine blades have been investigated. A numerical model guided wind tunnel testing, which used unsteady surface pressure measurements and phase-locked Particle Imaging Velocimetry to gather aerodynamic information. Using a torsionally compliant member, aeroelastic effects on the unsteady aerodynamics were compared against the results from a corresponding rigidly pitching airfoil to isolate the effects of compliance. The novel experimental apparatus and data acquisition techniques developed at the University of Wyoming showed that the presence of compliance can alter flow-field structures and increase dynamic loading. The high sensitivity of this nonlinear system suggests the formation of fluid-structure instabilities in large-scale turbines and demonstrates the potential for aerodynamic control as a means to mitigate adverse loading effects and improve wind turbine efficiency.

  17. Aerodynamic pressure measurements on a rotating wind turbine blade

    SciTech Connect

    Butterfield, C.P.; Jenks, M.D.; Simms, D.A.; Musial, W.P.

    1990-05-01

    A microprocessor-controlled measurement system has been designed and built to make accurate measurements of low pressures on a rotating wind turbine blade. This Pressure System Controller (PSC) is capable of simultaneously operating four pressure scanners (128 channels total) while rotating on a wind turbine blade. Calibrations and purge sequences are performed automatically on all 128 channels while the turbine is rotating. Data are fed to a Pulse Code Modulation (PCM) data-acquisition system and recorded on magnetic tape for later processing. Accurate measurements have been made down to pressures of 11 microbars (0.00018 psi) for low Reynolds Number tests. These rotating-blade pressure measurements are used to compare with wind tunnel data to see how blade rotation alters airfoil performance. A description of the test setup and instrumentation design is given along with examples results. Recommendations for future work and changes in the design approach are also discussed. 7 refs., 13 figs.

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

    SciTech Connect

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

    2008-03-01

    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.

  19. Wind Turbine Gearbox Failure Modes - A Brief (Presentation)

    SciTech Connect

    Sheng, S.; McDade, M.; Errichello, R.

    2011-10-01

    Wind turbine gearboxes are not always meeting 20-year design life. Premature failure of gearboxes increases cost of energy, turbine downtime, unplanned maintenance, gearbox replacement and rebuild, and increased warranty reserves. The problem is widespread, affects most Original Equipment Manufacturers, and is not caused by manufacturing practices. There is a need to improve gearbox reliability and reduce turbine downtime. The topics of this presentation are: GRC (Gearbox Reliability Collaborative) technical approach; Gearbox failure database; Recorded incidents summary; Top failure modes for bearings; Top failure modes for gears; GRC test gearbox; Bearing nomenclature; Test history; Real damage; Gear sets; Bearings; Observations; and Summary. 5 refs.

  20. Low-frequency noise from large wind turbines.

    PubMed

    Møller, Henrik; Pedersen, Christian Sejer

    2011-06-01

    As wind turbines get larger, worries have emerged that the turbine noise would move down in frequency and that the low-frequency noise would cause annoyance for the neighbors. The noise emission from 48 wind turbines with nominal electric power up to 3.6 MW is analyzed and discussed. The relative amount of low-frequency noise is higher for large turbines (2.3-3.6 MW) than for small turbines (? 2 MW), and the difference is statistically significant. The difference can also be expressed as a downward shift of the spectrum of approximately one-third of an octave. A further shift of similar size is suggested for future turbines in the 10-MW range. Due to the air absorption, the higher low-frequency content becomes even more pronounced, when sound pressure levels in relevant neighbor distances are considered. Even when A-weighted levels are considered, a substantial part of the noise is at low frequencies, and for several of the investigated large turbines, the one-third-octave band with the highest level is at or below 250 Hz. It is thus beyond any doubt that the low-frequency part of the spectrum plays an important role in the noise at the neighbors. PMID:21682397

  1. Simulation of winds as seen by a rotating vertical axis wind turbine blade

    SciTech Connect

    George, R.L.

    1984-02-01

    The objective of this report is to provide turbulent wind analyses relevant to the design and testing of Vertical Axis Wind Turbines (VAWT). A technique was developed for utilizing high-speed turbulence wind data from a line of seven anemometers at a single level to simulate the wind seen by a rotating VAWT blade. Twelve data cases, representing a range of wind speeds and stability classes, were selected from the large volume of data available from the Clayton, New Mexico, Vertical Plane Array (VPA) project. Simulations were run of the rotationally sampled wind speed relative to the earth, as well as the tangential and radial wind speeds, which are relative to the rotating wind turbine blade. Spectral analysis is used to compare and assess wind simulations from the different wind regimes, as well as from alternate wind measurement techniques. The variance in the wind speed at frequencies at or above the blade rotation rate is computed for all cases, and is used to quantitatively compare the VAWT simulations with Horizontal Axis Wind Turbine (HAWT) simulations. Qualitative comparisons are also made with direct wind measurements from a VAWT blade.

  2. Airfoil family design for large offshore wind turbine blades

    NASA Astrophysics Data System (ADS)

    Méndez, B.; Munduate, X.; San Miguel, U.

    2014-06-01

    Wind turbine blades size has scaled-up during last years due to wind turbine platform increase especially for offshore applications. The EOLIA project 2007-2010 (Spanish Goverment funded project) was focused on the design of large offshore wind turbines for deep waters. The project was managed by ACCIONA Energia and the wind turbine technology was designed by ACCIONA Windpower. The project included the design of a wind turbine airfoil family especially conceived for large offshore wind turbine blades, in the order of 5MW machine. Large offshore wind turbines suffer high extreme loads due to their size, in addition the lack of noise restrictions allow higher tip speeds. Consequently, the airfoils presented in this work are designed for high Reynolds numbers with the main goal of reducing blade loads and mantainig power production. The new airfoil family was designed in collaboration with CENER (Spanish National Renewable Energy Centre). The airfoil family was designed using a evolutionary algorithm based optimization tool with different objectives, both aerodynamic and structural, coupled with an airfoil geometry generation tool. Force coefficients of the designed airfoil were obtained using the panel code XFOIL in which the boundary layer/inviscid flow coupling is ineracted via surface transpiration model. The desing methodology includes a novel technique to define the objective functions based on normalizing the functions using weight parameters created from data of airfoils used as reference. Four airfoils have been designed, here three of them will be presented, with relative thickness of 18%, 21%, 25%, which have been verified with the in-house CFD code, Wind Multi Block WMB, and later validated with wind tunnel experiments. Some of the objectives for the designed airfoils concern the aerodynamic behavior (high efficiency and lift, high tangential coefficient, insensitivity to rough conditions, etc.), others concern the geometry (good for structural design, compatibility for the different airfoil family members, etc.) and with the ultimate objective that the airfoils will reduce the blade loads. In this paper the whole airfoil design process and the main characteristics of the airfoil family are described. Some force coefficients for the design Reynolds number are also presented. The new designed airfoils have been studied with computational calculations (panel method code and CFD) and also in a wind tunnel experimental campaign. Some of these results will be also presented in this paper.

  3. Analysis of the effects of integrating wind turbines into a conventional utility: a case study. Final report

    SciTech Connect

    Goldenblatt, M.K.; Wegley, H.L.; Miller, A.H.

    1982-08-01

    The impact on a utility incorporating wind turbine generation due to wind speed sampling frequency, wind turbine performance model, and wind speed forecasting accuracy is examined. The utility analyzed in the study was the Los Angeles Department of Water and Power and the wind turbine assumed was the MOD-2. The sensitivity of the economic value of wind turbine generation to wind speed sampling frequency and wind turbine modeling technique is examined as well as the impact of wind forecasting accuracy on utility operation and production costs. Wind speed data from San Gorgonio Pass, California during 1979 are used to estimate wind turbine performance using four different simulation methods. (LEW)

  4. Analysis of the effects of integrating wind turbines into a conventional utility: a case study. Revised final report

    SciTech Connect

    Goldenblatt, M.K.; Wegley, H.L.; Miller, A.H.

    1983-03-01

    The impact on a utility incorporating wind turbine generation due to wind speed sampling frequency, wind turbine performance model, and wind speed forecasting accuracy is examined. The utility analyzed in this study was the Los Angeles Department of Water and Power, and the wind turbine assumed was the MOD-2. The sensitivity of the economic value of wind turbine generation to wind speed sampling frequency and wind turbine modeling technique is examined as well as the impact of wind forecasting accuracy on utility operation and production costs. Wind speed data from San Gorgonio Pass, California during 1979 are used to estimate wind turbine performance using four different simulation methods. (LEW)

  5. Calculation of guaranteed mean power from wind turbine generators

    NASA Technical Reports Server (NTRS)

    Spera, D. A.

    1981-01-01

    A method for calculating the 'guaranteed mean' power output of a wind turbine generator is proposed. The term 'mean power' refers to the average power generated at specified wind speeds during short-term tests. Correlation of anemometers, the method of bins for analyzing non-steady data, the PROP Code for predicting turbine power, and statistical analysis of deviations in test data from theory are discussed. Guaranteed mean power density for the Clayton Mod-OA system was found to be 8 watts per square meter less than theoretical power density at all power levels, with a confidence level of 0.999. This amounts to 4 percent of rated power.

  6. Performance and flow analysis of vortex wind power turbines

    SciTech Connect

    Rangwalla, A.A.; Hsu, C.T.

    1982-10-01

    The theoretical study presented investigates some possible vortex flow solutions in the tornado-type wind energy system and evaluates the power coefficient that can be obtained theoretically. The actuator disc concept is applied to the vortex wind turbine configuration. The Burgers vortex model is then introduced and the performance of a turbine using it is derived. A generalized analytical solution of the model is given, followed by a numerical solution of the complete equations. The stability of a Burgers vortex is discussed. (LEW)

  7. Torque ripple in a Darrieus, vertical axis wind turbine

    SciTech Connect

    Reuter, R.C. Jr.

    1980-09-01

    Interaction between a steady wind and a rotating, Darrieus, vertical axis wind turbine produces time periodic aerodynamic loads which cause time dependent torque variations, referred to as torque ripple, to occur in the mechanical link between the turbine and the electrical generator. There is concern for the effect of torque ripple upon fatigue life of drive train components and upon power quality. An analytical solution characterizing the phenomenon of torque ripple has been obtained which is based upon a Fourier expansion of the time dependent features of the problem. Numerical results for torque ripple, some experimental data, determination of acceptable levels and methods of controlling it, are presented and discussed.

  8. Size Reduction of Permanent Magnet Generators for Wind Turbines with Higher Energy Density

    E-print Network

    McCalley, James D.

    be obtained from wind by 2030 [2]. Clearly, wind turbines with higher power ratings are necessary to achieve this goal. These larger wind turbines, as well as offshore development, will allow access to faster, more sustainable winds necessary to provide more power. Fig. 1. U.S. annual and cumulative wind power capacity

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

    SciTech Connect

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

    2014-04-01

    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 turbine 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.

  10. Anechoic wind tunnel study of turbulence effects on wind turbine broadband noise

    NASA Technical Reports Server (NTRS)

    Loyd, B.; Harris, W. L.

    1995-01-01

    This paper describes recent results obtained at MIT on the experimental and theoretical modelling of aerodynamic broadband noise generated by a downwind rotor horizontal axis wind turbine. The aerodynamic broadband noise generated by the wind turbine rotor is attributed to the interaction of ingested turbulence with the rotor blades. The turbulence was generated in the MIT anechoic wind tunnel facility with the aid of biplanar grids of various sizes. The spectra and the intensity of the aerodynamic broadband noise have been studied as a function of parameters which characterize the turbulence and of wind turbine performance parameters. Specifically, the longitudinal integral scale of turbulence, the size scale of turbulence, the number of turbine blades, and free stream velocity were varied. Simultaneous measurements of acoustic and turbulence signals were made. The sound pressure level was found to vary directly with the integral scale of the ingested turbulence but not with its intensity level. A theoretical model based on unsteady aerodynamics is proposed.

  11. Improved transformer-winding method

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1978-01-01

    Proposed technique using special bobbin and fixture to wind copper wire directly on core eliminates need core cut prior to assembly. Application of technique could result in production of quieter core with increased permeability and no localized heating.

  12. Effects of wind direction and wind farm layout on turbine wakes and power losses in wind farms: An LES study

    NASA Astrophysics Data System (ADS)

    Wu, Yu-Ting; Porté-Agel, Fernando

    2014-05-01

    A recently-developed large-eddy simulation (LES) framework is validated and used to investigate the effects of wind direction and wind farm layout on the turbine wakes and power losses in wind farms. The subgrid-scale (SGS) turbulent stress is parameterized using a tuning-free Lagrangian scale-dependent dynamic SGS model. The turbine-induced forces are computed using a dynamic actuator-disk model with rotation (ADM-R), which couples blade-element theory with a turbine-specific relation between the blade angular velocity and the shaft torque to compute simultaneously turbine angular velocity and power output. Here, we choose the Horns Rev offshore wind farm as a case study for model validation. A series of simulations are performed for a wide range of wind direction angles. Results from the simulations are in good agreement with observed power data from the Horns Rev wind farm, and show a strong impact of wind direction on the farm power production and the spatial distribution of turbine-wake characteristics (e.g., velocity deficit and turbulence intensity). This can be explained by the fact that changing the wind angle can be viewed as changing the wind farm layout relative to the incoming wind, while keeping the same wind turbine density. To further investigate the effect of wind farm layout on the flow and the power extracted by the farm, simulations of wind farms with different circular and elliptic layouts are performed to compare with the results of the Horns Rev wind farm simulations. The results show that the proposed layouts not only provide more stable power output with different wind directions, but also enhance the performance of the total farm power production.

  13. NREL Collaborates to Improve Wind Turbine Technology (Fact Sheet)

    SciTech Connect

    Not Available

    2012-01-01

    NREL's Gearbox Reliability Collaborative leads to wind turbine gearbox reliability, lowering the cost of energy. Unintended gearbox failures have a significant impact on the cost of wind farm operations. In 2007, the National Renewable Energy Laboratory (NREL) initiated the Gearbox Reliability Collaborative (GRC), which follows a multi-pronged approach based on a collaborative of manufacturers, owners, researchers, and consultants. The project combines analysis, field testing, dynamometer testing, condition monitoring, and the development and population of a gearbox failure database. NREL and other GRC partners have been able to identify shortcomings in the design, testing, and operation of wind turbines that contribute to reduced gearbox reliability. In contrast to private investigations of these problems, GRC findings are quickly shared among GRC participants, including many wind turbine manufacturers and equipment suppliers. Ultimately, the findings are made public for use throughout the wind industry. This knowledge will result in increased gearbox reliability and an overall reduction in the cost of wind energy. Project essentials include the development of two redesigned and heavily instrumented representative gearbox designs. Field and dynamometer tests are conducted on the gearboxes to build an understanding of how selected loads and events translate into bearing and gear response. The GRC evaluates and validates current wind turbine, gearbox, gear and bearing analytical tools/models, develops new tools/models, and recommends improvements to design and certification standards, as required. In addition, the GRC is investigating condition monitoring methods to improve turbine reliability. Gearbox deficiencies are the result of many factors, and the GRC team recommends efficient and cost-effective improvements in order to expand the industry knowledge base and facilitate immediate improvements in the gearbox life cycle.

  14. Methods of reducing wind power changes from large turbine arrays

    SciTech Connect

    Schlueter, R.; Dorsey, J.; Lotfalian, M.; Park, G.; Shayanfar, M.

    1983-06-01

    This paper discusses methods of reducing the WECS generation change through selection of the wind turbine model for each site, selection of an appropriate siting configuration, and wind array controls. An analysis of wind generation change from an echelon and a farm for passage of a thunderstorm is presented to establish the factors concerning the wind turbine model and siting configuration that contribute to these variations. Detailed simulation results indicate more precisely how these factors can be exploited to minimize the WECS generation changes observed. Reduction of the wind generation change over ten minutes is shown to reduce the increase in spinning reserve, unloadable generation and load following requirements on unit commitment when significant WECS generation is present and the farm penetration constraint is satisfied. Controls on the blade pitch angle of all wind turbines in an array or a battery control are shown to reduce both the wind generation change out of an array and the effective farm penetration in anticipation of a storm so that the farm penetration constraint may be satisfied.

  15. Wind-tunnel simulations of wind-turbine arrays in neutral and non-neutral winds

    NASA Astrophysics Data System (ADS)

    Hancock, P. E.; Farr, T. D.

    2014-06-01

    Wind tunnel simulations have been made of a neutral atmospheric boundary layer (ABL), a stable layer and an unstable layer, typical of offshore conditions, in order to better understand wake development and turbine-wake interactions. Measurements of the wake of a single turbine showed a slower reduction of the velocity deficit for the stable case, and a more rapid reduction for the unstable case, compared with the neutral. It is proposed that there are two effects of non-neutral conditions, indirect and direct. Indirect effects are seen in the earlier part of the wake, influenced by the turbulence level in the ABL but not by buoyancy forces directly; direct effects, caused by buoyancy forces, are seen further downstream. In the stable case, direct effects were seen from about 3 rotor diameters, while for the unstable case they were not seen until about 10 diameters. Two-point measurements in the wakes of four turbines aligned with the flow, compared with those of the ABL, exhibited very different flow characteristics, suggesting a lateral oscillation of the wakes of the later turbines. The effects of laterally adjacent turbines, in a 3-wide x 4-deep array, but with closer-than-typical lateral spacing (2.4 diameters) so as to give early interaction in the short array, were also investigated, and showed only limited interaction.

  16. Simulating dynamic interactions of grid-linked wind turbines

    SciTech Connect

    Chedid, R. ); LaWhite, N.; Ilic, M. )

    1994-10-01

    Wind power plants exhibit an unsteady input torque because of the sharp wind velocity variations with time. Normally, this could result in high mechanical stresses, generator instability, and voltage and frequency fluctuations on the utility network. Generating electric energy from wind has some unique features not shared by steam, hydro, or other electric energy conversion systems. These are the variability of resources, the dispersed character of generating units, and the low mechanical stiffness of the turbine generator that results from the use of a gearbox interface. These features characterize the electromechanical stress environment to which both the mechanical design allowance and quality of power are subjected. Models for dynamic interaction of wind turbine generators (WTGs) on electric utility networks have been suggested, but only a few publications have addressed the aggregation of hundreds of turbine generators. This topic has a significant impact on studies related to power system dynamics, because it helps reduce system complexity and computation cost. This article features a study that set out to: Simulate the electromechanical dynamics of a typical grid-connected wind turbine generator. Test an aggregation technique for representing a group of WTGs by a single unit. Demonstrate how such a complicated analysis of interconnected systems can be performed using state-of-the art software that performs both numerical simulation and linearized eigenstructure studies.

  17. Wind Turbine Shutdowns and Upgrades in Denmark: Timing Decisions and the Impact of Government Policy

    E-print Network

    Lin, C.-Y. Cynthia

    Wind Turbine Shutdowns and Upgrades in Denmark: Timing Decisions and the Impact of Government structural econometric model of wind turbine owners' decisions about whether and when to add new turbines the underlying profit structure for wind producers and evaluate the impact of technology and government policy

  18. AFFECT OF NEW BLADES ON NOISE REDUCTION OF SMALL WIND TURBINE WATER PUMPING SYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Acoustical noise data were collected on small wind turbines used for water pumping -- different blade designs were tested on each wind turbine. Three different blade designs were tested on 1 kW wind turbines and each successive blade design was shown to produce less noise with respect to rotor spee...

  19. Aalborg Universitet Efficiency and reliability improvement in wind turbine converters by grid converter

    E-print Network

    Munk-Nielsen, Stig

    was at the ground of the wind turbines development, and the synchronous generators are gaining significant attention are always welcome [3]. The generator is decoupled from the grid in the dc-link of the wind turbine converterAalborg Universitet Efficiency and reliability improvement in wind turbine converters by grid

  20. Optimization of wind turbine energy and power factor with an evolutionary computation algorithm

    E-print Network

    Kusiak, Andrew

    Optimization of wind turbine energy and power factor with an evolutionary computation algorithm 2009 Keywords: Wind turbine Power factor Power output Power quality Data mining Neural network Dynamic computation approach for optimization of power factor and power output of wind turbines is discussed. Data

  1. Maximizing the Performance of Wind Turbines with Nonlinear Aeroservoelastic Power Flow Control

    E-print Network

    1 Maximizing the Performance of Wind Turbines with Nonlinear Aeroservoelastic Power Flow Control by a wind turbine by operating at the edge of dynamic stall. This paper applies a novel nonlinear power flow of the first torsional mode of a nominal 5 MW rated power wind turbine blade. This model is analyzed using

  2. APPROPRIATE REALISATION OF GAIN-SCHEDULED CONTROLLERS WITH APPLICATION TO WIND TURBINE REGULATION

    E-print Network

    Duffy, Ken

    APPROPRIATE REALISATION OF GAIN-SCHEDULED CONTROLLERS WITH APPLICATION TO WIND TURBINE REGULATION D-regulated wind turbines presents a demanding control problem with the plant, actuation system and control. For the wind turbine nonlinear controller, realisations which satisfy the extended local linear equivalence

  3. Manufacturing Defects Common to Composite Wind Turbine Blades: Effects of Defects

    E-print Network

    1 Manufacturing Defects Common to Composite Wind Turbine Blades: Effects of Defects Jared W. Nelson The Blade Reliability Collaborative has been formed to perform comprehensive studies to improve wind turbine uni-directional wind turbine fiber-reinforced composite material with an epoxy resin were utilized

  4. Wind Turbine Selection: A case-study for Brfell, Iceland Samuel Perkin

    E-print Network

    Karlsson, Brynjar

    Wind Turbine Selection: A case-study for Búrfell, Iceland by Samuel Perkin 60 ECTS Thesis Master of Science in Sustainable Energy Engineering January 2014 #12;Wind Turbine Selection: A case: Magnus Þór Jónsson, Examiner Professor, University of Iceland, Iceland #12;Wind Turbine Selection: A case

  5. Large Scale Wind Turbine Siting Map Report NJ Department of Environmental Protection

    E-print Network

    Holberton, Rebecca L.

    Large Scale Wind Turbine Siting Map Report NJ Department of Environmental Protection September 8 Jersey Department of Environmental Protection's (NJDEP) "Large Scale Wind Turbine Siting Map Management rules to address the development and permitting of wind turbines in the coastal zone

  6. On the use of proper orthogonal decomposition to describe inflow turbulence and wind turbine loads

    E-print Network

    Manuel, Lance

    On the use of proper orthogonal decomposition to describe inflow turbulence and wind turbine loads, USA Keywords: Proper Orthogonal Decomposition, inflow turbulence, wind turbine ABSTRACT: We discuss experienced by a wind turbine. A methodology is proposed that employs low- dimensional POD models

  7. Impact of Modeling Approach on Flutter Predictions for Very Large Wind Turbine Blade Designs

    E-print Network

    Impact of Modeling Approach on Flutter Predictions for Very Large Wind Turbine Blade Designs Brian Recent predictions for very large wind turbine blades have indicated that flutter may be a significant with a NASTRAN based flutter prediction tool that was originally developed for vertical-axis wind turbine blades

  8. Civil&EnvironmentalEngineeringStructuresSeminar FullScale Structural Testing of Wind Turbine Blades

    E-print Network

    Civil&EnvironmentalEngineeringStructuresSeminar FullScale Structural Testing of Wind Turbine Blades Snell Noon Modern wind turbines are large structures with moving parts weighing many tons subjected effective renewable power generation over the lifetime of the machine. The blades of a wind turbine

  9. Turbulence in vertical axis wind turbine canopies Matthias Kinzel, Daniel B. Araya, and John O. Dabiri

    E-print Network

    Faraon, Andrei

    Turbulence in vertical axis wind turbine canopies Matthias Kinzel, Daniel B. Araya, and John O=pdfcov Published by the AIP Publishing Articles you may be interested in On the statistics of wind turbine wake of a hydroformed metal blade for vertical-axis wind turbines J. Renewable Sustainable Energy 7, 043135 (2015); 10

  10. Computational analysis of shrouded wind turbine configurations using a 3-dimensional RANS solver

    E-print Network

    Alonso, Juan J.

    Computational analysis of shrouded wind turbine configurations using a 3-dimensional RANS solver October 2014 Available online Keywords: Wind energy Shrouded wind turbines DAWT CFD Transition model a b and performance of shrouded turbines is assessed by solving the Reynolds Averaged NaviereStokes equations

  11. A Critical Assessment of Computer Tools for Calculating Composite Wind Turbine Blade Properties

    E-print Network

    Yu, Wenbin

    A Critical Assessment of Computer Tools for Calculating Composite Wind Turbine Blade Properties Hui assess several computer tools for calculating the inertial and structural properties of wind turbine, and a realistic composite wind turbine blade are used to evaluate the performance of different tools

  12. AIAA-2003-0696 ALTERNATIVE COMPOSITE MATERIALS FOR MEGAWATT-SCALE WIND TURBINE BLADES

    E-print Network

    AIAA-2003-0696 1 ALTERNATIVE COMPOSITE MATERIALS FOR MEGAWATT-SCALE WIND TURBINE BLADES: DESIGN blades for wind turbines in the multi-megawatt range. Earlier in this project constraints were identified years both the size of wind turbine blades and the volume of commercial production has been steadily

  13. Testing Small Wind Turbine Generators: Design of a Driving Dynamometer Stephen Rehmeyer Pepe

    E-print Network

    Kammen, Daniel M.

    Testing Small Wind Turbine Generators: Design of a Driving Dynamometer by Stephen Rehmeyer Pepe Sc, Berkeley Spring 2007 #12;Testing Small Wind Turbine Generators: Design of a Driving Dynamometer Copyright c 2007 by Stephen Rehmeyer Pepe #12;Abstract Testing Small Wind Turbine Generators: Design of a Driving

  14. Aalborg Universitet Disturbance Control of the Hydraulic Brake in a Wind Turbine

    E-print Network

    Yang, Zhenyu

    Aalborg Universitet Disturbance Control of the Hydraulic Brake in a Wind Turbine Jepsen, Frank Brake in a Wind Turbine. In Energy Conference and Exhibition (EnergyCon), 2010 IEEE International . (pp from vbn.aau.dk on: juli 07, 2015 #12;Disturbance Control of the Hydraulic Brake in a Wind Turbine

  15. PREDICTION OF DELAM INATION IN WIND TURBINE BLADE STRUCTURAL DETAILS John F. Mandell, Douglas S. Cairns

    E-print Network

    1 PREDICTION OF DELAM INATION IN WIND TURBINE BLADE STRUCTURAL DETAILS John F. Mandell, Douglas S materials structures such as wind turbine blades. Design methodologies to prevent such failures have static and fatigue loading. INTRODUCTION Composite material structures such as wind turbine blades

  16. Towards an Industry Data Gateway: An Integrated Platform for the Analysis of Wind Turbine Data

    E-print Network

    Towards an Industry Data Gateway: An Integrated Platform for the Analysis of Wind Turbine Data monitoring of sensor information from wind turbines, and how a data gateway can help to increase in the context of wind turbines. It goes on to describe the innovative approach used in VAVID to meet

  17. Assessment of Transition Model and CFD Methodology for Wind Turbine Flows

    E-print Network

    Alonso, Juan J.

    concept designs such as diffuser augmented wind turbines (DAWTs), active flow control, and plasmaAssessment of Transition Model and CFD Methodology for Wind Turbine Flows Aniket C. Aranake Vinod K Navier Stokes (RANS) solver with a transition model is performed for wind turbine applications

  18. Assessment of low-order theories for analysis and design of shrouded wind turbines using CFD

    E-print Network

    Alonso, Juan J.

    Assessment of low-order theories for analysis and design of shrouded wind turbines using CFD Aniket of a shroud around the rotor of a wind turbine has been known to augment the airflow through the rotor plane augmented wind turbines (DAWTs), promise greater power extraction and lower cut-in speeds than conventional

  19. AIAA-98-0057 RELATING TURBULENCE TO WIND TURBINE BLADE LOADS

    E-print Network

    Sweetman, Bert

    AIAA-98-0057 RELATING TURBULENCE TO WIND TURBINE BLADE LOADS: PARAMETRIC STUDY WITH MULTIPLE that is most useful in estimating fatigue loads on wind turbine blades. The histograms of rain ow counted for apwise loads on three horizontal axis wind tur- binesHAWTs. In the case of two of these turbines

  20. A Cyberinfrastructure for Integrated Monitoring and Life-Cycle Management of Wind Turbines

    E-print Network

    Stanford University

    A Cyberinfrastructure for Integrated Monitoring and Life-Cycle Management of Wind Turbines Kay Abstract. Integrating structural health monitoring into life-cycle management strategies for wind turbines data) can effectively be used to capture the operational and structural behavior of wind turbines

  1. Optimized Active Aerodynamic Blade Control for Load Alleviation on Large Wind Turbines

    E-print Network

    Optimized Active Aerodynamic Blade Control for Load Alleviation on Large Wind Turbines David G, Albuquerque, NM 87185 Wind turbines are large complex dynamically flexible structures that must operate un as a "wrapper" around a FAST/Simulink wind turbine analysis model. The time-domain simulation results

  2. "Development of a Free Vortex Wake Method Code for Offshore Floating Wind Turbines"

    E-print Network

    Mountziaris, T. J.

    "Development of a Free Vortex Wake Method Code for Offshore Floating Wind Turbines" Andrew Sciotti Professor Matthew Lackner Shujian Liu Offshore floating wind turbines (OFWTs) require a unique aerodynamic geographically factors that affect the wind flow, those of which that do not effect on land turbines. Thus

  3. Catching up: The rise of the Chinese wind turbine industry

    NASA Astrophysics Data System (ADS)

    Lefevre-Marton, Nicolas

    This thesis argues that Chinese firms can catch up with the technological frontier in the scope of new climate friendly energy technologies and provides a detailed study of the case of wind power. Chapter 2 assesses the nature and extent of wind turbine technology catch-up. Firstly, it uses various wind turbine technology indicators to detail the convergence of trends of leading Chinese firms with firms at the technological frontier. Secondly, the chapter assesses the evolution of technological capabilities among leading Chinese turbine manufacturers. It shows that Chinese firms were progressively introducing turbine technologies similar to those produced by frontier firms and had rapidly improved their capabilities, allowing them to increasingly rely on independent technology development efforts. Chapter 3 describes how the Chinese wind power technology development system, characterized by the presence of a powerful and proactive government, provided the necessary conditions for Chinese wind turbine manufacturers to make rapid technological progress. In particular, it highlights the policies introduced by the government to create a large and rapidly growing wind power market in China and the steps taken by the government to ensure that Chinese firms entered and progressively dominated the domestic turbine manufacturing market. The competition which ensued among domestic turbine manufacturers was arguably the main driver of technology development efforts. The most significant challenge to the continued progress of the industry was whether the Chinese system could transition from a model of technology development based on technology transfer to one based on its own innovation efforts. Chapter 4 shows that due to limited government support over the years in both Europe and the United States, the wind power technology frontier has evolved relatively slowly, making it easier for Chinese firms to catch up. Firstly, using patenting rates as indicators of knowledge development, the chapter shows a strong correlation between changes in government wind power support policies and patenting activity. Secondly, using both technology penetration rates and patenting trends, the chapter shows that the evolution of the wind power frontier was slow compared to most other technology sectors globally.

  4. Adaptive pitch control for load mitigation of wind turbines

    NASA Astrophysics Data System (ADS)

    Yuan, Yuan; Tang, J.

    2015-04-01

    In this research, model reference adaptive control is examined for the pitch control of wind turbines that may suffer from reduced life owing to extreme loads and fatigue when operated under a high wind speed. Specifically, we aim at making a trade-off between the maximum energy captured and the load induced. The adaptive controller is designed to track the optimal generator speed and at the same time to mitigate component loads under turbulent wind field and other uncertainties. The proposed algorithm is tested on the NREL offshore 5-MW baseline wind turbine, and its performance is compared with that those of the gain scheduled proportional integral (GSPI) control and the disturbance accommodating control (DAC). The results show that the blade root flapwise load can be reduced at a slight expense of optimal power output. The generator speed regulation under adaptive controller is better than DAC.

  5. Wind turbine having a direct-drive drivetrain

    SciTech Connect

    Bevington, Christopher M.; Bywaters, Garrett L.; Coleman, Clint C.; Costin, Daniel P.; Danforth, William L.; Lynch, Jonathan A.; Rolland, Robert H.

    2008-10-07

    A wind turbine (100) comprising an electrical generator (108) that includes a rotor assembly (112). A wind rotor (104) that includes a wind rotor hub (124) is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle (160) via a bearing assembly (180). The wind rotor hub includes an opening (244) having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity (380) inside the wind rotor hub. The spindle is attached to a turret (140) supported by a tower (136). Each of the spindle, turret and tower has an interior cavity (172, 176, 368) that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system (276) for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly.

  6. Dynamically Adjustable Wind Turbine Blades: Adaptive Turbine Blades, Blown Wing Technology for Low-Cost Wind Power

    SciTech Connect

    2010-02-02

    Broad Funding Opportunity Announcement Project: Caitin is developing wind turbines with a control system that delivers compressed air from special slots located in the surface of its blades. The compressed air dynamically adjusts the aerodynamic performance of the blades, and can essentially be used to control lift, drag, and ultimately power. This control system has been shown to exhibit high levels of control in combination with an exceptionally fast response rate. The deployment of such a control system in modern wind turbines would lead to better management of the load on the system during peak usage, allowing larger blades to be deployed with a resulting increase in energy production.

  7. Low Wind Speed Turbine Project Phase II: The Application of Medium-Voltage Electrical Apparatus to the Class of Variable Speed Multi-Megawatt Low Wind Speed Turbines; 15 June 2004--30 April 2005

    SciTech Connect

    Erdman, W.; Behnke, M.

    2005-11-01

    Kilowatt ratings of modern wind turbines have progressed rapidly from 50 kW to 1,800 kW over the past 25 years, with 3.0- to 7.5-MW turbines expected in the next 5 years. The premise of this study is simple: The rapid growth of wind turbine power ratings and the corresponding growth in turbine electrical generation systems and associated controls are quickly making low-voltage (LV) electrical design approaches cost-ineffective. This report provides design detail and compares the cost of energy (COE) between commercial LV-class wind power machines and emerging medium-voltage (MV)-class multi-megawatt wind technology. The key finding is that a 2.5% reduction in the COE can be achieved by moving from LV to MV systems. This is a conservative estimate, with a 3% to 3.5% reduction believed to be attainable once purchase orders to support a 250-turbine/year production level are placed. This evaluation considers capital costs as well as installation, maintenance, and training requirements for wind turbine maintenance personnel. Subsystems investigated include the generator, pendant cables, variable-speed converter, and padmount transformer with switchgear. Both current-source and voltage-source converter/inverter MV topologies are compared against their low-voltage, voltage-source counterparts at the 3.0-, 5.0-, and 7.5-MW levels.

  8. Test evaluation of a laminated wood wind turbine blade concept

    NASA Technical Reports Server (NTRS)

    Faddoul, J. R.

    1981-01-01

    A series of tests conducted on a root end section of a laminated wood wind turbine blade are reported. The blade to hub transition of the wood blade uses steel studs cast into the wood D spar with a filled epoxy. Both individual studs and a full scale, short length, root section were tested. Results indicate that the bonded stud concept is more than adequate for both the 30 year life fatigue loads and for the high wind or hurricane gust loads.

  9. Energy harvesting to power sensing hardware onboard wind turbine blade

    SciTech Connect

    Carlson, Clinton P; Schichting, Alexander D; Quellette, Scott; Farinholt, Kevin M; Park, Gyuhae

    2009-10-05

    Wind turbines are becoming a larger source of renewable energy in the United States. However, most of the designs are geared toward the weather conditions seen in Europe. Also, in the United States, manufacturers have been increasing the length of the turbine blades, often made of composite materials, to maximize power output. As a result of the more severe loading conditions in the United States and the material level flaws in composite structures, blade failure has been a more common occurrence in the U.S. than in Europe. Therefore, it is imperative that a structural health monitoring system be incorporated into the design of the wind turbines in order to monitor flaws before they lead to a catastrophic failure. Due to the rotation of the turbine and issues related to lightning strikes, the best way to implement a structural health monitoring system would be to use a network of wireless sensor nodes. In order to provide power to these sensor nodes, piezoelectric, thermoelectric and photovoltaic energy harvesting techniques are examined on a cross section of a CX-100 wind turbine blade in order to determine the feasibility of powering individual nodes that would compose the sensor network.

  10. Feasibility of Floating Platform Systems for Wind Turbines: Preprint

    SciTech Connect

    Musial, W.; Butterfield, S.; Boone, A.

    2003-11-01

    This paper provides a general technical description of several types of floating platforms for wind turbines. Platform topologies are classified into multiple- or single-turbine floaters and by mooring method. Platforms using catenary mooring systems are contrasted to vertical mooring systems and the advantages and disadvantages are discussed. Specific anchor types are described in detail. A rough cost comparison is performed for two different platform architectures using a generic 5-MW wind turbine. One platform is a Dutch study of a tri-floater platform using a catenary mooring system, and the other is a mono-column tension-leg platform developed at the National Renewable Energy Laboratory. Cost estimates showed that single unit production cost is $7.1 M for the Dutch tri-floater, and $6.5 M for the NREL TLP concept. However, value engineering, multiple unit series production, and platform/turbine system optimization can lower the unit platform costs to $4.26 M and $2.88 M, respectively, with significant potential to reduce cost further with system optimization. These foundation costs are within the range necessary to bring the cost of energy down to the DOE target range of $0.05/kWh for large-scale deployment of offshore floating wind turbines.

  11. Stratificaiton Effects on wake of large wind turbines in wind farm

    NASA Astrophysics Data System (ADS)

    Bhaganagar, Kiran; Debnath, Mithu

    2013-11-01

    The focus of the present talk is to demonstrate the interplay of the complex interactions between the wind turbulence and the wake turbulence under different stratification conditions. Large eddy simulation (LES) has been used to simulate flow over multi mega-watt wind turbines. The results have revealed different empirical relations for the mean velocity deficit decay and turbulence kinetic energy decay rates in the wake region of the wind turbine. The simulation for wind farm has revealed the wake decay rates as a function of the radial and streamwise distance from the upstream wind turbine. Vertical mixing plays a major role in altering the flow dynamics in the wake region. Support from NSF CBET-1348480, NSF HRD-1242180 and TACC Supercomputing.

  12. Spanwise aerodynamic loads on a rotating wind turbine blade

    SciTech Connect

    Butterfield, C.P.; Simms, D.; Musial, W.; Scott, G.

    1990-10-01

    Wind turbine performance and load predictions depend on accurate airfoil performance data. Wind tunnel test data are typically used which accurately describe two-dimensional airfoil performance characteristics. Usually these data are only available for a range of angles of attack from 0 to 15 deg, which excludes the stall characteristics. Airfoils on stall-controlled wind turbines operate in deep stall in medium to high winds. Therefore it is very important to know how the airfoil will perform in these high load conditions. Butterfield et al. have shown that three-dimensional effects and rotation of the blade modify the two-dimensional performance of the airfoil. These effects are modified to different degrees throughout the blade span. The Solar Energy Research Institute (SERI) has conducted a series of tests to measure the spanwise variation of airfoil performance characteristics on a rotating wind turbine blade. Maximum lift coefficients were measured to be 200% greater than wind tunnel results at the 30% span. Stall characteristics were generally modified throughout the span. Lift characteristics were unmodified for low to medium angles of attack. This paper discusses these test results for four spanwise locations. 8 refs., 12 figs.

  13. Theoretical design study of the MSFC wind-wheel turbine

    NASA Technical Reports Server (NTRS)

    Frost, W.; Kessel, P. A.

    1982-01-01

    A wind wheel turbine (WWT) is studied. Evaluation of the probable performance, possible practical applications, and economic viability as compared to other conventional wind energy systems is discussed. The WWT apparatus is essentially a bladed wheel which is directly exposed to the wind on the upper half and exposed to wind through multiple ducting on the lower half. The multiple ducts consist of a forward duct (front concentrator) and two side ducts (side concentrators). The forced rotation of the wheel is then converted to power through appropriate subsystems. Test results on two simple models, a paper model and a stainless steel model, are reported. Measured values of power coefficients over wind speeds ranging from 4 to 16 m/s are given. An analytical model of a four bladed wheel is also developed. Overall design features of the wind turbine are evaluated and discussed. Turbine sizing is specified for a 5 and 25 kW machine. Suggested improvements to the original design to increase performance and performance predictions for an improved WWT design are given.

  14. Shrouded wind turbine research in Israel

    NASA Astrophysics Data System (ADS)

    Igra, O.

    1981-04-01

    Experimental results are presented which demonstrate that enclosing a turbine inside a specially designed shroud will increase its power output by a factor of two; with the prospect of augmentation factors as high as four resulting from the use of coaxial annular trailing flaps and boundary layer laminarization techniques such as surface suction. The power-augmenting characteristics of shrouds are due to (1) the inviscid wake-recovery effect, which produces a sub-atmospheric pressure region at the shroud exit plane, and (2) the conversion of kinetic energy to a rise in pressure inside the rear part of the shroud. Preliminary economic studies indicate that the shrouded turbine would have lower specific power costs than conventional turbines in at least two power-rating regimes.

  15. 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…

  16. NREL Computer Models Integrate Wind Turbines with Floating Platforms (Fact Sheet)

    SciTech Connect

    Not Available

    2011-07-01

    Far off the shores of energy-hungry coastal cities, powerful winds blow over the open ocean, where the water is too deep for today's seabed-mounted offshore wind turbines. For the United States to tap into these vast offshore wind energy resources, wind turbines must be mounted on floating platforms to be cost effective. Researchers at the National Renewable Energy Laboratory (NREL) are supporting that development with computer models that allow detailed analyses of such floating wind turbines.

  17. Control of Next Generation Aircraft and Wind Turbines

    NASA Technical Reports Server (NTRS)

    Frost, Susan

    2010-01-01

    The first part of this talk will describe some of the exciting new next generation aircraft that NASA is proposing for the future. These aircraft are being designed to reduce aircraft fuel consumption and environmental impact. Reducing the aircraft weight is one approach that will be used to achieve these goals. A new control framework will be presented that enables lighter, more flexible aircraft to maintain aircraft handling qualities, while preventing the aircraft from exceeding structural load limits. The second part of the talk will give an overview of utility-scale wind turbines and their control. Results of collaboration with Dr. Balas will be presented, including new theory to adaptively control the turbine in the presence of structural modes, with the focus on the application of this theory to a high-fidelity simulation of a wind turbine.

  18. 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.

  19. Structural Monitoring of Wind Turbines using Wireless Sensor Networks

    E-print Network

    Sweetman, Bert

    1 Structural Monitoring of Wind Turbines using Wireless Sensor Networks R. Andrew Swartz1 , Jerome years, low-cost wireless sensors have emerged as an enabling technology for just such monitoring applications. Inexpensive and flexible wireless sensors can be installed within a large structure to measure

  20. Industrial Wind Turbine Development and Loss of Social Justice?

    ERIC Educational Resources Information Center

    Krogh, Carmen M. E.

    2011-01-01

    This article explores the loss of social justice reported by individuals living in the environs of industrial wind turbines (IWTs). References indicate that some individuals residing in proximity to IWT facilities experience adverse health effects. These adverse health effects are severe enough that some families have abandoned their homes.…

  1. Occupational Health and Industrial Wind Turbines: A Case Study

    ERIC Educational Resources Information Center

    Rand, Robert W.; Ambrose, Stephen E.; Krogh, Carmen M. E.

    2011-01-01

    Industrial wind turbines (IWTs) are being installed at a fast pace globally. Researchers, medical practitioners, and media have reported adverse health effects resulting from living in the environs of IWTs. While there have been some anecdotal reports from technicians and other workers who work in the environs of IWTs, little is known about the…

  2. Literature Reviews on Wind Turbines and Health: Are They Enough?

    ERIC Educational Resources Information Center

    Horner, Brett; Jeffery, Roy D.; Krogh, Carmen M. E.

    2011-01-01

    Industrial wind turbines (IWTs) are a new source of community noise to which relatively few people have yet been exposed. IWTs are being erected at a rapid pace in proximity to human habitation. Some people report experiencing adverse health effects as a result of living in the environs of IWTs. In order to address public concerns and assess the…

  3. Powering the Future: A Wind Turbine Design Challenge

    ERIC Educational Resources Information Center

    Pries, Caitlin Hicks; Hughes, Julie

    2011-01-01

    Nothing brings out the best in eighth-grade physical science students quite like an engineering challenge. The wind turbine design challenge described in this article has proved to be a favorite among students with its focus on teamwork and creativity and its (almost) sneaky reinforcement of numerous physics concepts. For this activity, pairs of…

  4. Vibration-based SHM System: Application to Wind Turbine Blades

    E-print Network

    Vibration-based SHM System: Application to Wind Turbine Blades D Tcherniak1, L L Mølgaard2 1 Research Engineer, Br¨uel & Kjær Sound & Vibration Measurement A/S, Nærum, Denmark 2 Senior Researcher-mail: dmitri.tcherniak@bksv.com Abstract. This study presents an vibration-based system designed for structural

  5. Investigation of excitation control for wind-turbine generator stability

    NASA Technical Reports Server (NTRS)

    Gebben, V. D.

    1977-01-01

    High speed horizontal axis wind turbine generators with blades on the downwind side of the support tower require special design considerations to handle disturbances introduced by the flow wake behind the tower. Experiments and analytical analyses were made to determine benefits that might be obtained by using the generator exciter to provide system damping for reducing power fluctuations.

  6. Method of making a wooden wind turbine blade

    DOEpatents

    Coleman, C.

    1984-08-14

    A wooden wind turbine blade is formed by laminating wood veneer in a compression mold having the exact curvature needed for one side of the blade, following which the other side of the blade is ground flat along its length but twisted with respect to the blade axis. 8 figs.

  7. Control of wind turbine generators connected to power systems

    NASA Technical Reports Server (NTRS)

    Hwang, H. H.; Mozeico, H. V.; Gilbert, L. J.

    1978-01-01

    A unique simulation model based on a Mode-O wind turbine is developed for simulating both speed and power control. An analytical representation for a wind turbine that employs blade pitch angle feedback control is presented, and a mathematical model is formulated. For Mode-O serving as a practical case study, results of a computer simulation of the model as applied to the problems of synchronization and dynamic stability are provided. It is shown that the speed and output of a wind turbine can be satisfactorily controlled within reasonable limits by employing the existing blade pitch control system under specified conditions. For power control, an additional excitation control is required so that the terminal voltage, output power factor, and armature current can be held within narrow limits. As a result, the variation of torque angle is limited even if speed control is not implemented simultaneously with power control. Design features of the ERDA/NASA 100-kW Mode-O wind turbine are included.

  8. Method of making a wooden wind turbine blade

    DOEpatents

    Coleman, Clint (Warren, VT)

    1984-01-01

    A wooden wind turbine blade is formed by laminating wood veneer in a compression mold having the exact curvature needed for one side of the blade, following which the other side of the blade is ground flat along its length but twisted with respect to the blade axis.

  9. How to protect a wind turbine from lightning

    NASA Technical Reports Server (NTRS)

    Dodd, C. W.; Mccalla, T., Jr.; Smith, J. G.

    1983-01-01

    Techniques for reducing the chances of lightning damage to wind turbines are discussed. The methods of providing a ground for a lightning strike are discussed. Then details are given on ways to protect electronic systems, generating and power equipment, blades, and mechanical components from direct and nearby lightning strikes.

  10. An aeroelastic analysis of the Darrieus wind turbine

    SciTech Connect

    Meyer, E.E.; Smith, C.E.

    1981-01-01

    The stability of a single Darrieus wind turbine blade spinning in still air is investigated using linearized equations of motion. The three most dangerous flutter modes are characterized for a one-parameter family of blades. In addition, the influence of blade density, mass and aerodynamic center offsets, and structural damping is presented.

  11. Aeroelastic analysis of a troposkien-type wind turbine blade

    NASA Technical Reports Server (NTRS)

    Nitzsche, F.

    1981-01-01

    The linear aeroelastic equations for one curved blade of a vertical axis wind turbine in state vector form are presented. The method is based on a simple integrating matrix scheme together with the transfer matrix idea. The method is proposed as a convenient way of solving the associated eigenvalue problem for general support conditions.

  12. Thermal stress analysis for a wood composite blade. [wind turbines

    NASA Technical Reports Server (NTRS)

    Fu, K. C.; Harb, A.

    1984-01-01

    Heat conduction throughout the blade and the distribution of thermal stresses caused by the temperature distribution were determined for a laminated wood wind turbine blade in both the horizontal and vertical positions. Results show that blade cracking is not due to thermal stresses induced by insulation. A method and practical example of thermal stress analysis for an engineering body of orthotropic materials is presented.

  13. NEN 6096, design resolution for small wind turbines

    NASA Astrophysics Data System (ADS)

    Ottens, H. H.; Machielse, L. A. H.

    1988-01-01

    A draft regulation for safety for windturbine (NEN 6096) was published in the Netherlands. Special attention was paid to structural safety. In the final version, the results of the project Design criteria for small wind turbines were incorporated. The methodology and terminology of the draft design standards for buildings (NEN 6700 series) were adapted.

  14. 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.

  15. Full Life Wind Turbine Gearbox Lubricating Fluids

    SciTech Connect

    Lutz, Glenn A.; Jungk, Manfred; Bryant, Jonathan J.; Lauer, Rebecca S.; Chobot, Anthony; Mayer, Tyler; Palmer, Shane; Kauffman, Robert E.

    2012-02-28

    Industrial gear box lubricants typically are hydrocarbon based mineral oils with considerable amounts of additives to overcome the lack of base fluid properties like wear protection, oxidation stability, load carrying capacity, low temperature solidification and drop of viscosity at higher temperatures. For today's wind turbine gearboxes, the requirements are more severe and synthetic hydrocarbon oils are used to improve on this, but all such hydrocarbon based lubricants require significant amounts of Extreme Pressure (EP) additives to meet performance requirements. Perfluoropolyether (PFPE) fluids provide load carrying capacity as an inherent property. During the course of the project with the main tasks of 'Establish a Benchmark', 'Lubricant Evaluation', 'Full Scale Gearbox Trial' and 'Economic Evaluation', the PAO Reference oil exhibited significant changes after laboratory gear testing, in service operation in the field and full scale gearbox trial. Four hydrocarbon base oils were selected for comparison in the benchmarking exercise and showed variation with respect to meeting the requirements for the laboratory micro-pitting tests, while the PFPE fluid exceeded the requirements even with the material taken after the full scale gear box trial. This is remarkable for a lubricant without EP additives. Laboratory bearing tests performed on the PFPE fluids before and after the full scale gear box trial showed the results met requirements for the industry standard. The PFPE fluid successfully completed the full scale gear box test program which included baseline and progressive staged load testing. The evaluation of gears showed no micro-pitting or objectionable wear. By the final stage, lubricant film thickness had been reduced to just 21% of its original value, this was by design and resulted in a lambda ratio of well below 1. This test design scenario of a low lambda ratio is a very undesirable lubrication condition for real world but creates the ability to test the lubricating fluids performance under the most extreme conditions. The PAO Reference oil also passed its testing without any noticeable deterioration of the gear surface. However the PAO Reference oil was replaced midway through the progressive loading, as the lubricant was burned in an attempt to raise the sump temperature to the same levels as for the PFPE. Both materials experienced a decrease of viscosity during their respective run times. The viscosity index decreased for the PAO there while there was a slight increase for the PFPE. FZG laboratory gear tests and measurements of the drive motor's current during the full scale gear box trial were made to characterize the relative efficiency between the PFPE fluid and the PAO Reference oil. In the FZG laboratory efficiency test, the PFPE fluids show much higher churning losses due to their higher viscosity and density. The analysis seems to show that the efficiency correlates better to dynamic viscosity than any other of the measured metrics such as film thickness. In load stages where the load, speed and temperature are similar, the PFPE fluid has a greater film thickness and theoretical gear protection, but requires a larger current for the drive motor than the PAO. However in load stages where the film thickness is the same, the PFPE fluid's reduced dynamic viscosity gives it a slight efficiency advantage relative to the PAO reference oil. Ultimately, many factors such as temperature, rotational speed, and fluid viscosity combine in a complex fashion to influence the results. However, the PFPE's much lower change of viscosity with respect to temperature, allows variations in designing an optimum viscosity to balance efficiency versus gear protection. Economic analysis was done using Cost of Energy calculations. The results vary from 5.3% for a 'Likely Case' to 16.8% for a 'Best Case' scenario as potential cost improvement by using PFPE as the gearbox lubricating fluid. It is important to note the largest portion of savings comes in Levelized Replacement Cost, which is dictated by the assumption on gearb

  16. Operating Modes of a Teeter-Rotor Wind Turbine

    SciTech Connect

    Bir, G. S.; Stol, K.

    1999-02-25

    We examine the operating modes of a two-bladed teetered wind turbine. Because of the gyroscopic asymmetry of its rotor, this turbine's dynamics can be quite distinct from those of a turbine with three or more blades. This asymmetry leads to system equations with periodic coefficients that are solved using the Floquet approach to extract the correct modal parameters. The system equations are derived using a simple analytical model with four degrees of freedom: cacelle yaw, rotor teeter, and flapping associated with each blade. Results confirm that the turbine modes become more dominated by the centrifugal and gyroscopic effects as the rotor speed increases. They gyroscopic effect may also cause dynamic instability. Under certain design conditions, yaw and teeter modal frequencies may coalesce.

  17. Uncovering wind turbine properties through two-dimensional stochastic modeling of wind dynamics

    E-print Network

    Raischel, Frank; Lopes, Vitor V; Lind, Pedro G

    2012-01-01

    Using a method for stochastic data analysis, borrowed from statistical physics, we analyze synthetic data from a Markov chain model that reproduces measurements of wind speed and power production in a wind park in Portugal. From the theoretical point of view we argue that our methods can be used to extract unknown functional relations between two variables. We first show that indeed our analysis retrieves the power performance curve, which yields the relationship between wind speed and power production and discuss how such procedure can be extended for extracting functional relationships between pairs of physical variables in general. Second, we show how specific features, such as the turbine rated wind speed or the descriptive wind speed statistics, can be related with the equations describing the evolution of power production and wind speed at single wind turbines.

  18. Reliability analysis for wind turbines with incomplete failure data collected from after the date of initial installation

    E-print Network

    McCalley, James D.

    Reliability analysis for wind turbines with incomplete failure data collected from after the date model Maximum likelihood Least squares Wind turbines a b s t r a c t Reliability has an impact on wind analysis. In wind energy industry, wind farm operators have greater interest in recording wind turbine

  19. Reconstructing the intermittent dynamics of the torque in wind turbines

    NASA Astrophysics Data System (ADS)

    Lind, Pedro G.; Wächter, Matthias; Peinke, Joachim

    2014-06-01

    We apply a framework introduced in the late nineties to analyze load measurements in off-shore wind energy converters (WEC). The framework is borrowed from statistical physics and properly adapted to the analysis of multivariate data comprising wind velocity, power production and torque measurements, taken at one single WEC. In particular, we assume that wind statistics drives the fluctuations of the torque produced in the wind turbine and show how to extract an evolution equation of the Langevin type for the torque driven by the wind velocity. It is known that the intermittent nature of the atmosphere, i.e. of the wind field, is transferred to the power production of a wind energy converter and consequently to the shaft torque. We show that the derived stochastic differential equation quantifies the dynamical coupling of the measured fluctuating properties as well as it reproduces the intermittency observed in the data. Finally, we discuss our approach in the light of turbine monitoring, a particular important issue in off-shore wind farms.

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

    SciTech Connect

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

    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, meaning these waked turbines will produce less power.

  1. Assessment of research needs for wind turbine rotor materials technology

    SciTech Connect

    Not Available

    1991-01-01

    Wind-driven power systems is a renewable energy technology that is still in the early stages of development. Wind power plants installed in early 1980s suffered structural failures chiefly because of incomplete understanding of wind forces (turbulent), in some cases because of poor product quality. Failures of rotor blades are now somewhat better understood. This committee has examined the experience base accumulated by wind turbines and the R and D programs sponsored by DOE. It is concluded that a wind energy system such as is described is within the capability of engineering practice; however because of certain gaps in knowledge, and the presence of only one major integrated manufacturer of wind power machines in the USA, a DOE R and D investment is still required.

  2. Investigation of aerodynamic braking devices for wind turbine applications

    SciTech Connect

    Griffin, D.A.

    1997-04-01

    This report documents the selection and preliminary design of a new aerodynamic braking system for use on the stall-regulated AWT-26/27 wind turbines. The goal was to identify and design a configuration that offered improvements over the existing tip brake used by Advanced Wind Turbines, Inc. (AWT). Although the design objectives and approach of this report are specific to aerodynamic braking of AWT-26/27 turbines, many of the issues addressed in this work are applicable to a wider class of turbines. The performance trends and design choices presented in this report should be of general use to wind turbine designers who are considering alternative aerodynamic braking methods. A literature search was combined with preliminary work on device sizing, loads and mechanical design. Candidate configurations were assessed on their potential for benefits in the areas of cost, weight, aerodynamic noise, reliability and performance under icing conditions. As a result, two configurations were identified for further study: the {open_quotes}spoiler-flap{close_quotes} and the {open_quotes}flip-tip.{close_quotes} Wind tunnel experiments were conducted at Wichita State University to evaluate the performance of the candidate aerodynamic brakes on an airfoil section representative of the AWT-26/27 blades. The wind tunnel data were used to predict the braking effectiveness and deployment characteristics of the candidate devices for a wide range of design parameters. The evaluation was iterative, with mechanical design and structural analysis being conducted in parallel with the braking performance studies. The preliminary estimate of the spoiler-flap system cost was $150 less than the production AWT-26/27 tip vanes. This represents a reduction of approximately 5 % in the cost of the aerodynamic braking system. In view of the preliminary nature of the design, it would be prudent to plan for contingencies in both cost and weight.

  3. Cascade Analysis of a Floating Wind Turbine Rotor

    NASA Astrophysics Data System (ADS)

    Eliassen, Lene; Jakobsen, Jasna B.; Knauer, Andreas; Nielsen, Finn Gunnar

    2014-12-01

    Mounting a wind turbine on a floating foundation introduces more complexity to the aerodynamic loading. The floater motion contains a wide range of frequencies. To study some of the basic dynamic load effect on the blades due to these motions, a two-dimensional cascade approach, combined with a potential vortex method, is used. This is an alternative method to study the aeroelastic behavior of wind turbines that is different from the traditional blade element momentum method. The analysis tool demands little computational power relative to a full three dimensional vortex method, and can handle unsteady flows. When using the cascade plane, a "cut" is made at a section of the wind turbine blade. The flow is viewed parallel to the blade axis at this cut. The cascade model is commonly used for analysis of turbo machineries. Due to the simplicity of the code it requires little computational resources, however it has limitations in its validity. It can only handle two-dimensional potential flow, i.e. including neither three-dimensional effects, such as the tip loss effect, nor boundary layers and stall effects are modeled. The computational tool can however be valuable in the overall analysis of floating wind turbines, and evaluation of the rotor control system. A check of the validity of the vortex panel code using an airfoil profile is performed, comparing the variation of the lift force, to the theoretically derived Wagner function. To analyse the floating wind turbine, a floating structure with hub height 90 m is chosen. An axial motion of the rotor is considered.

  4. Bird flight characteristics near wind turbines in Minnesota

    USGS Publications Warehouse

    Osborn, R.G.; Dieter, C.D.; Higgins, K.F.; Usgaard, R.E.

    1998-01-01

    During 1994-1995, we saw 70 species of birds on the Buffalo Ridge Wind Resource Area. In both years bird abundance peaked in spring. Red-winged blackbirds (Agelaius phoeniceus), mallards (Anas platyrhynchos), common grackles (Quiscalus quiscula), and barn swallows (Hirundo rustica) were the species most commonly seen. Most birds (82-84%) flew above or below the height range of wind turbine blades (22-55 m). The Buffalo Ridge Wind Resource Area poses little threat to resident or migrating birds at its current operating level.

  5. Experimental characterization of vertical-axis wind turbine noise.

    PubMed

    Pearson, C E; Graham, W R

    2015-01-01

    Vertical-axis wind turbines are wind-energy generators suitable for use in urban environments. Their associated noise thus needs to be characterized and understood. As a first step, this work investigates the relative importance of harmonic and broadband contributions via model-scale wind-tunnel experiments. Cross-spectra from a pair of flush-mounted wall microphones exhibit both components, but further analysis shows that the broadband dominates at frequencies corresponding to the audible range in full-scale operation. This observation has detrimental implications for noise-prediction reliability and hence also for acoustic design optimization. PMID:25618090

  6. Wind Turbine Wake Experiment - Wieringermeer (WINTWEX-W)

    NASA Astrophysics Data System (ADS)

    Kumer, V. M.; Reuder, J.; Svardal, B.; Eecen, P.

    2014-12-01

    WINTWEX-W is a cooperative wake measurement campaign conducted by the Norwegian Centre of Offshore Wind Energy (Norcowe) and the Energy Research Centre of the Netherlands (ECN). A scanning, four static Windcubes as well as a downstream looking nacelle LiDAR were placed for half a year downstream of one of five research wind turbines in ECNs' wind turbine test farm Wieringermeer. In order to capture wake characteristics under different weather conditions we scanned a 60? sector at three different elevations and two vertical cross-sections every minute. Windcubes v1 measured wind profiles every second at 2, 5 and 12 rotor diameter downstream distances. Another static Windcube, a forward-looking nacelle LiDAR and three Sonics were placed upstream to measure the undisturbed approaching flow field. The aim of the campaign is a qualitative and quantitative description of single wind turbine wake propagation and persistency, as well as to improve CFD wake models by delivering a detailed data set of several real atmospheric conditions.

  7. A REAL OPTIONS OPTIMIZATION MODEL TO MEET AVAILABILITY REQUIREMENTS FOR OFFSHORE WIND TURBINES

    E-print Network

    Sandborn, Peter

    wind farm with prognostic capabilities. Alternative energy sources such as offshore wind turbines to invest in renewable energy sources. Offshore wind has become of subject of interest to the DoE [2] and [31 A REAL OPTIONS OPTIMIZATION MODEL TO MEET AVAILABILITY REQUIREMENTS FOR OFFSHORE WIND TURBINES

  8. SMART wind turbine rotor. Data analysis and conclusions

    SciTech Connect

    Berg, Jonathan Charles; Barone, Matthew Franklin; Yoder, Nathanael C.

    2014-01-01

    The Wind Energy Technologies department at Sandia National Laboratories has developed and field tested a wind turbine rotor with integrated trailing-edge flaps designed for active control of the rotor aerodynamics. The SMART Rotor project was funded by the Wind and Water Power Technologies Office of the U.S. Department of Energy (DOE) and was conducted to demonstrate active rotor control and evaluate simulation tools available for active control research. This report documents the data post-processing and analysis performed to date on the field test data. Results include the control capability of the trailing edge flaps, the combined structural and aerodynamic damping observed through application of step actuation with ensemble averaging, direct observation of time delays associated with aerodynamic response, and techniques for characterizing an operating turbine with active rotor control.

  9. Predicting aerodynamic characteristic of typical wind turbine airfoils using CFD

    SciTech Connect

    Wolfe, W.P.; Ochs, S.S.

    1997-09-01

    An investigation was conducted into the capabilities and accuracy of a representative computational fluid dynamics code to predict the flow field and aerodynamic characteristics of typical wind-turbine airfoils. Comparisons of the computed pressure and aerodynamic coefficients were made with wind tunnel data. This work highlights two areas in CFD that require further investigation and development in order to enable accurate numerical simulations of flow about current generation wind-turbine airfoils: transition prediction and turbulence modeling. The results show that the laminar-to turbulent transition point must be modeled correctly to get accurate simulations for attached flow. Calculations also show that the standard turbulence model used in most commercial CFD codes, the k-e model, is not appropriate at angles of attack with flow separation. 14 refs., 28 figs., 4 tabs.

  10. Wind/Wave Misalignment in the Loads Analysis of a Floating Offshore Wind Turbine: Preprint

    SciTech Connect

    Barj, L.; Stewart, S.; Stewart, G.; Lackner, M.; Jonkman, J.; Robertson, A.

    2014-02-01

    Wind resources far from the shore and in deeper seas have encouraged the offshore wind industry to look into floating platforms. The International Electrotechnical Commission (IEC) is developing a new technical specification for the design of floating offshore wind turbines that extends existing design standards for land-based and fixed-bottom offshore wind turbines. The work summarized in this paper supports the development of best practices and simulation requirements in the loads analysis of floating offshore wind turbines by examining the impact of wind/wave misalignment on the system loads under normal operation. Simulations of the OC3-Hywind floating offshore wind turbine system under a wide range of wind speeds, significant wave heights, peak-spectral periods and wind/wave misalignments have been carried out with the aero-servo-hydro-elastic tool FAST [4]. The extreme and fatigue loads have been calculated for all the simulations. The extreme and fatigue loading as a function of wind/wave misalignment have been represented as load roses and a directional binning sensitivity study has been carried out. This study focused on identifying the number and type of wind/wave misalignment simulations needed to accurately capture the extreme and fatigue loads of the system in all possible metocean conditions considered, and for a down-selected set identified as the generic US East Coast site. For this axisymmetric platform, perpendicular wind and waves play an important role in the support structure and including these cases in the design loads analysis can improve the estimation of extreme and fatigue loads. However, most structural locations see their highest extreme and fatigue loads with aligned wind and waves. These results are specific to the spar type platform, but it is expected that the results presented here will be similar to other floating platforms.

  11. 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. PMID:25583859

  12. Dynamic instability of small-scale wind turbine blades

    NASA Astrophysics Data System (ADS)

    Pourazarm, Pariya; Modarres-Sadeghi, Yahya; Lackner, Matthew

    2013-11-01

    Future wind turbine blades will become larger, and therefore more flexible. For more flexible blades, the ratio of the estimated critical speed for dynamic instability to the operating speed decreases, and the blades are more susceptible to such instabilities. In the current work, the dynamic instability of a rotating wind turbine blade is studied using a numerical stability analysis and supported by experimental results. For the experimental component of the work, a series of tests were conducted in a wind tunnel. The blades were designed using relatively thin, low Reynolds number airfoils and built using rapid-prototyping methods with a flexible material. As the oncoming wind speed was increased, the beam natural frequencies varied, up to a critical wind speed at which two structural modes coalesced and resulted in a coupled-mode flutter. A theoretical model based on coupled flexural-torsional beam equations subjected to aerodynamic loadings is derived to study the flow-induced instability for the designed blade. The model also predicts the onset of instability at a critical wind speed at which one of the structural modes experiences a negative damping. The support provided by the Wind Technology Testing Center, a part of the Massachusetts Clean Energy Center is acknowledged.

  13. Wind tunnel experiments to prove a hydraulic passive torque control concept for variable speed wind turbines

    NASA Astrophysics Data System (ADS)

    Diepeveen, N. F. B.; Jarquin-Laguna, A.

    2014-12-01

    In this paper the results are presented of experiments to prove an innovative concept for passive torque control of variable speed wind turbines using fluid power technology. It is demonstrated that by correctly configuring the hydraulic drive train, the wind turbine rotor operates at or near maximum aerodynamic efficiency for below rated wind speeds. The experiments with a small horizontal-axis wind turbine rotor, coupled to a hydraulic circuit, were conducted at the Open Jet Facility of the Delft University of Technology. In theory, the placement of a nozzle at the end of the hydraulic circuit causes the pressure and hence the rotor torque to increase quadratically with flow speed and hence rotation speed. The rotor torque is limited by a pressure relief valve. Results from the experiments proved the functionality of this passive speed control concept. By selecting the correct nozzle outlet area the rotor operates at or near the optimum tip speed ratio.

  14. The UTRC wind energy conversion system performance analysis for horizontal axis wind turbines (WECSPER)

    NASA Technical Reports Server (NTRS)

    Egolf, T. A.; Landgrebe, A. J.

    1981-01-01

    The theory for the UTRC Energy Conversion System Performance Analysis (WECSPER) for the prediction of horizontal axis wind turbine performance is presented. Major features of the analysis are the ability to: (1) treat the wind turbine blades as lifting lines with a prescribed wake model; (2) solve for the wake-induced inflow and blade circulation using real nonlinear airfoil data; and (3) iterate internally to obtain a compatible wake transport velocity and blade loading solution. This analysis also provides an approximate treatment of wake distortions due to tower shadow or wind shear profiles. Finally, selected results of internal UTRC application of the analysis to existing wind turbines and correlation with limited test data are described.

  15. 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.

  16. A model of rotationally-sampled wind turbulence for predicting fatigue loads in wind turbines

    NASA Technical Reports Server (NTRS)

    Spera, David A.

    1995-01-01

    Empirical equations are presented with which to model rotationally-sampled (R-S) turbulence for input to structural-dynamic computer codes and the calculation of wind turbine fatigue loads. These equations are derived from R-S turbulence data which were measured at the vertical-plane array in Clayton, New Mexico. For validation, the equations are applied to the calculation of cyclic flapwise blade loads for the NASA/DOE Mod-2 2.5-MW experimental HAWT's (horizontal-axis wind turbines), and the results compared to measured cyclic loads. Good correlation is achieved, indicating that the R-S turbulence model developed in this study contains the characteristics of the wind which produce many of the fatigue loads sustained by wind turbines. Empirical factors are included which permit the prediction of load levels at specified percentiles of occurrence, which is required for the generation of fatigue load spectra and the prediction of the fatigue lifetime of structures.

  17. Lightning Protection of Wind Turbine Generation System

    NASA Astrophysics Data System (ADS)

    Yokoyama, Shigeru; Sekioka, Shozo

    The rapid increase of wind power plants and enlargement of capacity makes the lightning problem of the wind power plants including blades serious. This report summarizes the result of the comprehensive surveillance study carried out for these several years. The contents lightning outages, the lightning phenomena and the result of the electric discharge experiment in connection with the measure against lightning of a windmill blades. Furthermore, the state of the present condition of the protective measures in the blades of windmill, mechanical parts, connecting power lines and communication lines was also considered. Especially grounding methods for wind power plants are considered.

  18. Energetic Turbulence Structures in the Wake of Model Wind Turbines

    NASA Astrophysics Data System (ADS)

    Sheng, Jian; Mehdi, Faraz; Chamorro, Leonardo P.

    2013-11-01

    Wind turbine wakes contain complex and energetic flow structures. Characterizing the near-wake field is critical to assess flow-structure interactions and evaluate asymmetric loadings that trigger premature structural failure. Although the turbulence flow structure in the far-wake region is important in the wind farm design, an integrated characterization of the entire wake flow would provide clearer mechanistic view on other phenomena such wake meandering and unsteady interactions with the blades of downwind turbines. High-speed Particle Image Velocimetry (PIV) is carried out over a model wind turbine in a neutrally stratified boundary layer flow. The measurements are made at consecutive locations ranging from three rotor diameters upstream to twelve rotor diameters downstream of the unit. Vortical structures within the wake including tip, root and hub vortices are identified and followed as they advect downstream. The evolution of these dominant near-wake flow structures are quantified and provide us a better understanding of interactions between turbine wake and boundary layer. The spatial distribution of the mean and fluctuating velocity, as well as energy spectrum and turbulent kinetic budget are also discussed.

  19. The wake of a single vertical axis wind turbine

    NASA Astrophysics Data System (ADS)

    Barsky, Danielle A.; Leftwich, Megan C.

    2013-11-01

    The purpose of this study is to measure the wake of a Windspire vertical axis wind turbine (VAWT). In recent years, research on VAWTs has increased due to various potential advantages over the more common horizontal axis wind turbines (HAWTs). Unlike very large HAWTs, moderately sized-and virtually silent-VAWTs can be placed in urban and suburban regions where land space is limited. To date, many VAWT studies have assumed that the turbine has the same aerodynamic structure as a spinning cylinder despite a significant increase in geometric complexity. This experiment attempts to understand the fundamental wake structure of a single VAWT (and compare it to the wake structure of a spinning cylinder). In this experiment, a scaled-down VAWT is placed inside a wind tunnel under a controlled laboratory setting. A motor rotates the scale model at a constant angular speed. Stereo particle image velocimetry (PIV) is used to visualize the wake of the turbine and image processing techniques are used to quantify the velocity and vorticity of the wake.

  20. Baseline Design of a Hurricane-Resilient Wind Turbine (Poster)

    SciTech Connect

    Damiani, R.; Robertson, A.; Schreck, S.; Maples, B.; Anderson, M.; Finucane, Z.; Raina, A.

    2014-10-01

    Under U.S. Department of Energy-sponsored research FOA 415, the National Renewable Energy Laboratory led a team of research groups to produce a complete design of a large wind turbine system to be deployable in the western Gulf of Mexico region. As such, the turbine and its support structure would be subjected to hurricane-loading conditions. Among the goals of this research was the exploration of advanced and innovative configurations that would help decrease the levelized cost of energy (LCOE) of the design, and the expansion of the basic IEC design load cases (DLCs) to include hurricane environmental conditions. The wind turbine chosen was a three-bladed, downwind, direct-drive, 10-MW rated machine. The rotor blade was optimized based on an IEC load suite analysis. The drivetrain and nacelle components were scaled up from a smaller sized turbine using industry best practices. The tubular steel tower was sized using ultimate load values derived from the rotor optimization analysis. The substructure is an innovative battered and raked jacket structure. The innovative turbine has also been modeled within an aero-servo-hydro-elastic tool, and future papers will discuss results of the dynamic response analysis for select DLCs. Although multiple design iterations could not be performed because of limited resources in this study, and are left to future research, the obtained data will offer a good indication of the expected LCOE for large offshore wind turbines to be deployed in subtropical U.S. waters, and the impact design innovations can have on this value.