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1

Overview of power converter designs feasible for high voltage transformer-less wind turbine  

Microsoft Academic Search

Many leading wind turbine manufacturers are pushing forward in variable-speed wind turbines, often exceeding 5 MW. Therefore, novel designs and concepts for optimal high power wind turbines appeared. One of the most promising concepts is the high voltage (10-35 kV) transformer-less topology. High voltage design enables low power losses and elimination of bulky step-up transformer from the wind turbine system.

Michal Sztykiel

2011-01-01

2

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....

2009-10-19

3

Wind turbine  

Microsoft Academic Search

A wind turbine to convert wind energy into hydraulic energy by a positive displacement hydraulic pump driven by a wind mill. To the oil outlet of the hydraulic pump, a thermo-sensitive control element is attached, which functions when the oil temperature exceeds a certain limit. By the control element, the oil outlet is closed, suppressed, or opened to ensure safety

Kita

1983-01-01

4

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

SciTech Connect

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.

Bir, G. S.

2010-09-01

5

Wind turbine  

DOEpatents

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.

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

1982-01-01

6

Wind turbine  

SciTech Connect

The improvement in a wind turbine comprises providing a tower with a freely liftable mount and adapting a nacelle which is fitted with a propeller windwheel consisting of a plurality of rotor blades and provided therein with means for conversion of wind energy to be shifted onto said mount attached to the tower. In case of a violent wind storm, the nacelle can be lowered down to the ground to protect the rotor blades from breakage due to the force of the wind. Required maintenance and inspection of the nacelle and replacement of rotor blades can be safely carried out on the ground.

Abe, M.

1982-01-19

7

Wind turbine  

Microsoft Academic Search

An improved wind turbine is described in which the tip portions of the blades are variable in pitch and are cyclically varied in pitch to control the yaw of the rotor and to relieve bending moments on the blades and are collectively varied in pitch to relieve bending moments on the blades and to maximize the power output of the

R. E. Donham; R. L. Heimbold

1981-01-01

8

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

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

9

Wind turbine  

SciTech Connect

A wind turbine assembly including a rotor body is described having mounted thereon a plurality of rotor blades, wherein each of the rotor blades is joined at an inner extremity the blade stem projection extending interiorly into the rotor body and secured there within to the rotor body by torsional- and axial-shock damping connection means, wherein each blade stem projection comprises a hollow cylindrical housing defining a central longitudinal axis therein, with a support member interiorly disposed in the housing at an intermediate position along its axis and fixedly secured to the housing, a shaft fixedly secured at one end thereof to the rotor body and coupled at its other end with the support member in a manner allowing limited axial and rotational movement of the housing relative to the rotor body, and a longitudinally outwardly biasing means between the support member and the rotor body, extending along the axis of the housing and outwardly abuttingly biased against the support member, whereby the biasing means provides torsional and axial shock damping to the rotor blade. The wind turbine assembly includes a nacelle to which the rotor body is coupled for rotation with respect to the nacelle, and a tower having an upper portion to which the nacelle is secured by coupling means, and a lower portion positionable on a support body, the tower upper portion including a cylindrical member at an upper end of the tower, an oarlock connector joined to the bottom stem portion; a pitch biasing and damping member interconnecting the nacelle and the oarlock connector, for pitch damping of the nacelle; and yaw biasing and damping means connecting the oarlock and upper portion of the tower, whereby the pitch damping/biasing member and the yaw biasing and damping means bias the rotor body and nacelle to a selected base position in relation to the tower, and dampen pitch and yaw displacements from said base position.

Lundquist, R.E.

1993-05-25

10

Wind turbine wake aerodynamics  

Microsoft Academic Search

The aerodynamics of horizontal axis wind turbine wakes is studied. The contents is directed towards the physics of power extraction by wind turbines and reviews both the near and the far wake region. For the near wake, the survey is restricted to uniform, steady and parallel flow conditions, thereby excluding wind shear, wind speed and rotor setting changes and yawed

L. J. Vermeer; J. N. Sørensen; A. Crespo

2003-01-01

11

Wind turbine apparatus  

US Patent & Trademark Office Database

A wind turbine apparatus including a shaft, two wind turbines, and a two-piece alternator. The turbines and the alternator are mounted on the shaft. The alternator is located between the turbines. The alternator includes a circular permanent magnet component fixed to the first turbine, and a circular electrical winding component fixed to the second turbine so that, when an effective wind blows in a direction perpendicular to the longitudinal axis of the shaft, the first turbine and the circular magnet component will rotate around the shaft in a first direction and the second turbine and the circular winding component will rotate around the shaft in a second direction opposite the first direction, thereby generating electrical energy.

2013-01-22

12

Wind turbine system  

Microsoft Academic Search

A wind turbine system utilizes a bicycle wheel type turbine having airfoils mounted on various spoke pairs. The vertical yaw axis lies in the horizontal projection of the airfoils to offer better control of the system; for example, automatic stowage in the case of excessive wind is provided since the superstructure of the turbine provides a torque around the vertical

1982-01-01

13

Wind Turbine Noise  

Microsoft Academic Search

Following an introduction to noise and noise regulation of wind turbines, the problem of adverse health effects of turbine noise is discussed. This is attributed to the characteristics of turbine noise and deficiencies in the regulation of this noise. Both onshore and offshore wind farms are discussed.

John P. Harrison

2011-01-01

14

Wind Turbines Benefit Crops  

SciTech Connect

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.

Takle, Gene

2010-01-01

15

Wind Turbines Benefit Crops  

ScienceCinema

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.

Takle, Gene

2013-03-01

16

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. ...

2009-10-19

17

Advanced wind turbine design  

Microsoft Academic Search

Garrad Hassan have a project in progress funded by the U.K. Department of Trade and Industry (DTI) to assess the prospects and cost benefits of advanced wind turbine design. In the course of this work, a new concept, the coned rotor design, has been developed. This enables a wind turbine system to operate in effect with variable rotor diameter augmenting

P. M. Jamieson; A. Jaffrey

1997-01-01

18

Vertical axis wind turbine  

Microsoft Academic Search

A Darrieus-type vertical axis wind turbine is disclosed which includes a vertically extending rotor tube mounted on a support structure with two or three rotor blades of troposkein configuration on the rotor tube for rotating the tube in response to wind energy and thereby drive a generator to produce electrical power. The turbine includes an erection hinge which permits assembly

Kutcher

1984-01-01

19

Wind turbine acoustics  

NASA Technical Reports Server (NTRS)

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.

Hubbard, Harvey H.; Shepherd, Kevin P.

1990-01-01

20

Wind turbines at work  

SciTech Connect

This paper describes how multimegawatt wind-turbine generators are being integrated with electric power systems in oil-dependent, wind-rich areas. Details are given on the wind turbines designed for the US DOE and operated by Pacific Gas and Electric in California and by the Bonneville Power Administration near Goldendale, Washington. It is shown how the Public Utility Regulatory Policies Act of 1978, requiring utilities to purchase power at fair rates from independent generators of wind, will encourage small operations and accelerate the use of wind power. Environmental problems include electromagnetic interference and noise pollution. Presents an annotated bibliography.

Cadogan, J.B.; Ancona, D.F.

1982-08-01

21

Build a Wind Turbine  

NSDL National Science Digital Library

Learners build a wind turbine and test it to see how much energy is created. Learners can build a variety of wind blades, test a variety of wind speeds and see what effect these have on the energy created. Adult supervision recommended.

Museum Of Science And Industry, Chicago

2012-01-01

22

Wind Turbine Blade Design  

NSDL National Science Digital Library

Students go through the design process and the scientific method to test the effect of blade design on power output. There is an optional extension to use the data to create an optimal set of wind turbine blades.

Project, Kidwind

23

Advanced wind turbine design  

SciTech Connect

Garrad Hassan have a project in progress funded by the U.K. Department of Trade and Industry (DTI) to assess the prospects and cost benefits of advanced wind turbine design. In the course of this work, a new concept, the coned rotor design, has been developed. This enables a wind turbine system to operate in effect with variable rotor diameter augmenting energy capture in light winds and shedding loads in storm conditions. Comparisons with conventional design suggest that a major benefit in reduced cost of wind-generated electricity may be possible.

Jamieson, P.M.; Jaffrey, A. [Garrad Hassan and Partners, Ltd., Glasgow (United Kingdom)

1997-11-01

24

Vertical axis wind turbines  

DOEpatents

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.

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

2011-03-08

25

Wind Turbine Blade Design  

NSDL National Science Digital Library

In this activity, learners design, build and test wind turbines. Learners go through the design process and use the scientific method to test important blade variables. Learners then use this data to create an optimal set of wind turbine blades. Educators can do the basic lesson in 3-4 class periods (about 3-4 hours) or extend the activity with a larger challenge that takes 5-7 class periods in total (about 5-7 hours).

Project, Kidwind

2006-01-01

26

Alcoa wind turbines  

NASA Technical Reports Server (NTRS)

An overview of Alcoa's wind energy program is given with emphasis on the the development of a low cost, reliable Darrieus Vertical Axis Wind Turbine System. The design layouts and drawings for fabrication are now complete, while fabrication and installation to utilize the design are expected to begin shortly.

Ai, D. K.

1979-01-01

27

Wind turbine with governor  

Microsoft Academic Search

A wind turbine assembly is described which comprises a supporting framework including a rigid elevated platform, a turntable rotatably supported from the platform for swivelling movement about a substantially vertical axis, a horizontal shaft rotatably journalled from the turntable with the end portions of the shaft projecting diametrically therefrom, a plurality of wind wheels mounted on each end of the

1974-01-01

28

Floating wind turbine system  

NASA Technical Reports Server (NTRS)

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.

Viterna, Larry A. (Inventor)

2009-01-01

29

Air flow behind wind turbines  

Microsoft Academic Search

Wind turbine wakes have been studied by analysing a large set of atomospheric data, from a wind farm with four turbines sited on a flat coastal area. The results obtained have been generalized to allow tests against data from other full scale wind turbines as well as wind tunnel simulations. These comparisons are found to give very satisfactory results. Most

M. Magnusson; A.-S. Smedman

1999-01-01

30

Design of wind turbine controller by using wind turbine codes  

Microsoft Academic Search

The wind turbine codes predict wind turbine loads and response in high accuracy and can be used in controller design with the development of the computer technologies. In this paper open source FAST code developed by NREL is studied. The wind turbine controller is designed in the Matlab\\/Simulink environment and the FAST code is modeled as an S-function. The simulation

Jianzhong Zhang; Ming Cheng; Zhe Chen

2008-01-01

31

Predicting Noise From Wind Turbines  

NASA Technical Reports Server (NTRS)

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.

Grosveld, Ferdinand W.

1990-01-01

32

Airborne Wind Turbine  

SciTech Connect

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.

None

2010-09-01

33

Tornado type wind turbines  

DOEpatents

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.

Hsu, Cheng-Ting (Ames, IA) [Ames, IA

1984-01-01

34

Wind Turbine Fatigue Considerations.  

National Technical Information Service (NTIS)

Current methods of analyzing wind turbine fatigue life are reviewed and found to be inadequate. One reason for this inadequacy is that these methods treat material fatigue properties as well-defined values, when they are, in fact, more accurately describe...

D. Berg

1985-01-01

35

Wind turbine spoiler  

DOEpatents

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.

Sullivan, William N. (Albuquerque, NM) [Albuquerque, NM

1985-01-01

36

Airship-floated wind turbine  

Microsoft Academic Search

A wind turbine, by use of a tethered airship for support, may be designed for the economical recovery of power at heights of 2,000 feet or more above ground, at which height power density in the wind is typically three times the power density available to a conventionally supported wind turbine. Means can be added to such an airship-floated wind

1985-01-01

37

Build a Wind Turbine  

NSDL National Science Digital Library

This hands-on project provides step-by-step instructions for building a vertical axis wind turbine in secondary classrooms. The 17-page construction plans may be freely downloaded and are organized for first-time builders. Comprehensive background information on wind energy and renewable energy are provided. Registered teacher-users also have access to supporting lesson plans. All of the materials are readily available in hardware or grocery stores. This resource, which meets multiple national science standards, was developed to spark students' interest in learning more about renewable energy sources and the science and engineering principles that underlie the harnessing of renewable power. Editor's Note: Wind turbines work by using an internal generator to convert the mechanical energy of the spinning turbine shaft into electricity. This particular project is modeled after the Savonius rotor system, which uses uses drag -- not lift -- to capture energy for making electricity. Although it isn't as efficient as a conventional horizontal axis turbine, it is much easier to build.

38

Wind Turbine With Concentric Ducts  

NASA Technical Reports Server (NTRS)

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

Muhonen, A. J.

1983-01-01

39

Wind turbine acoustic standards  

NASA Technical Reports Server (NTRS)

A program is being conducted to develop noise standards for wind turbines which minimize annoyance and which can be used to design specifications. The approach consists of presenting wind turbine noise stimuli to test subjects in a laboratory listening chamber. The responses of the subjects are recorded for a range of stimuli which encompass the designs, operating conditions, and ambient noise levels of current and future installations. Results to date have established the threshold of detectability for a range of impulsive stimuli of the type associated with blade/tower wake interactions. The status of the ongoing psychoacoustic tests, the subjective data, and the approach to the development of acoustic criteria/standards are described.

Stephens, D. G.; Shepherd, K. P.; Grosveld, F.

1981-01-01

40

Optimum propeller wind turbines  

SciTech Connect

The Prandtl-Betz-Theodorsen theory of heavily loaded airscrews has been adapted to the design of propeller windmills which are to be optimized for maximum power coefficient. It is shown that the simpler, light-loading, constant-area wake assumption can generate significantly different ''optimum'' performance and geometry, and that it is therefore not appropriate to the design of propeller wind turbines when operating in their normal range of high-tip-speed-to-wind-speed ratio. Design curves for optimum power coefficient are presented and an example of the design of a typical two-blade optimum rotor is given.

Sanderson, R.J.; Archer, R.D.

1983-11-01

41

Airfoils for wind turbine  

DOEpatents

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.

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

1996-01-01

42

Airfoils for wind turbine  

DOEpatents

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.

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

1996-10-08

43

Make Your Own Wind Turbine  

NSDL National Science Digital Library

In this activity, learners create a wind turbine model using a simple pattern, a thumbtack, and a pencil with an eraser. After constructing the model, learners blow on the wind turbine to simulate the wind. Use this activity to introduce alternative energy and electricity generation.

History, National M.

2012-06-26

44

Small Wind Turbine Technology Assessment.  

National Technical Information Service (NTIS)

The result of the study carried out under the scope of the ATYCA project Test Plant of Wind Systems for Isolated Applications, about the state of art of the small wind turbine technology (wind turbines with swept area smaller than 40 m''2) is presented. T...

F. Avia Aranda I. Cruz Cruz

1999-01-01

45

SERI advanced wind turbine blades  

Microsoft Academic Search

The primary goal of the Solar Energy Research Institute's (SERI) advanced wind turbine blades is to convert the kinetic energy in the wind into mechanical energy in an inexpensive and efficient manner. To accomplish this goal, advanced wind turbine blades have been developed by SERI that utilize unique airfoil technology. Performance characteristics of the advanced blades were verified through atmospheric

J. Tangler; B. Smith; D. Jager

1992-01-01

46

Wind turbines power curve variability  

Microsoft Academic Search

A comprehensive measurement programme was carried through 300 kW Nordtank stall-regulated horizontal axis wind turbine. These turbines were erected at the test station for windmills by Hurghada Wind Energy Technology Centre. To the extent necessary to understand the measurement carried out, all experimental set up systems must be described. This paper describes the annual wind speed variability in Hurghada city

Mohammed G. Khalfallah; Aboelyazied M. Koliub

2007-01-01

47

Airship-floated wind turbine  

SciTech Connect

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

Watson, W. K.

1985-01-01

48

Development of Wind Turbine Simulators Using PSCAD  

Microsoft Academic Search

In this paper, a wind turbine simulator is developed using PSCAD. The wind turbine static characteristics are modeled using the relation among the turbine power, the wind speed, and the blade pitch angle. Also, the dynamic characteristics of the wind turbine are modeled through a two-mass oscillating system, representing the turbine and the generator connected by elastic shaft. The system

A. G. Abo-Khalil

2006-01-01

49

Superconducting wind turbine generators  

NASA Astrophysics Data System (ADS)

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.

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

50

Towers for Offshore Wind Turbines  

NASA Astrophysics Data System (ADS)

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.

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

2010-06-01

51

Wind tunnel investigation on wind turbine wakes and wind farms  

NASA Astrophysics Data System (ADS)

The interaction between atmospheric boundary layer and wind farms leads to flow modifications, which need to be deeply characterized in order to relate them to wind farm performance. The wake flow produced from a wind farm is the result of a strong interaction between multiple turbine wakes, so that the wind farm configuration turns out to be one of the dominant features to enhance power production. For the present work a wind tunnel investigation was carried out with hot-wire anemometry and velocity measurements performed with multi-hole pressure probes. The tested wind farms consist of miniature three-bladed wind turbine models. Preliminarily, the wake flow generated from a single wind turbine is surveyed, which is characterized by a strong velocity defect lying in proximity of the wind turbine hub height. The wake gradually recovers by moving downstream; the characteristics of the incoming boundary layer and wind turbulence intensity can strongly affect the wake recovery, and thus performance of following wind turbines. An increased turbulence level is typically detected downstream of each wind turbine for heights comparable to the wind turbine blade top-tip. These wake flow fluctuations produce increased fatigue loads on the following wind turbines within a wind farm, which could represent a significant hazard for real wind turbines. Dynamics of vorticity structures present in wind turbine wakes are also investigated; particular attention is paid to the downstream evolution of the tip helicoidal vortices and to oscillations of the hub vortex. The effect of wind farm layout on power production is deeply investigated. Particular emphasis is placed on studying how the flow adjusts as it moves inside the wind farm and can affect the power production. Aligned and staggered wind farm configurations are analysed, also with varying separation distances in the streamwise and spanwise directions. The present experimental results are being used to test and guide the development of improved parameterizations of wind turbines in high-resolution numerical models, such as large-eddy simulations (LES).

Iungo, G. V.; Coëffé, J.; Porté-Agel, F.

2012-04-01

52

Modal analysis of wind turbine tower  

Microsoft Academic Search

As the support structure of wind turbine, the tower bears alternating loads of wind when the wind turbine runs. To ensure the reliability of the wind turbine, it's necessary to carry out modal analysis on the tower, and this would prevent the natural frequency of the tower close to the rated speed of wind turbine. In this paper, finite element

Jie Chen; Dongxiang Jiang

2010-01-01

53

On the Fatigue Analysis of Wind Turbines  

Microsoft Academic Search

Modern wind turbines are fatigue critical machines that are typically used to produce electricalpower from the wind. Operational experiences with these large rotating machines indicated thattheir components (primarily blades and blade joints) were failing at unexpectedly high rates, whichled the wind turbine community to develop fatigue analysis capabilities for wind turbines. Ourability to analyze the fatigue behavior of wind turbine

Herbert J. Sutherland

1999-01-01

54

Chapter 14: Wind Turbine Control Systems  

Microsoft Academic Search

Wind turbines are complex, nonlinear, dynamic systems forced by gravity, stochastic wind disturbances, and gravitational, centrifugal, and gyroscopic loads. The aerodynamic behavior of wind turbines is nonlinear, unsteady, and complex. Turbine rotors are subjected to a complicated three-dimensional turbulent wind inflow field that drives fatigue loading. Wind turbine modeling is also complex and challenging. Accurate models must contain many degrees

2009-01-01

55

A Review of Modern Wind Turbine Technology  

Microsoft Academic Search

This article deals with a review of modern wind turbine technology. Wind energy for electricity production today is a mature, competitive, and virtually pollution-free technology widely used in many areas of the world. Wind technology converts the energy available in wind to electricity or mechanical power through the use of wind turbines. A wind turbine is a machine for converting

M. Balat

2009-01-01

56

Effective Lightning Protection For Wind Turbine Generators  

Microsoft Academic Search

A wind turbine generator is the most exposed of all types of generators connected to electric utility systems. Wind turbines are most often erected in hostile lightning environments. Lightning damage to wind turbines is costly in terms of repair and replacement of equipment. Lightning damage is the single largest cause of unplanned downtime in wind turbines, and that downtime is

Bruce Glushakow

2007-01-01

57

Wind turbine rotor aileron  

DOEpatents

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.

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

1994-06-14

58

Wind and solar powered turbine  

Microsoft Academic Search

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

I. D. Wells; J. L. Koh; M. Holmes

1984-01-01

59

Siting technologies for large wind turbine clusters  

Microsoft Academic Search

Site selection for large wind turbine clusters requires thorough documentation of the wind characteristics at the site, because of the influence these characteristics will have on the economics, operations, and service life of the wind turbines. The wind prospecting strategy can be used by a utility to determine specific locations for each wind turbine in a cluster of 10 to

T. R. Hiester; W. T. Pennell

1979-01-01

60

A Data-Mining Approach to Monitoring Wind Turbines  

Microsoft Academic Search

The rapid expansion of wind farms has generated interest in operations and maintenance. An operating wind turbine undergoes various state changes, including transformation from a normal to a fault mode. Condition-based maintenance tools are needed to identify potential faults in the system. The prediction of turbine fault modes is of particular interest. In this research, data-mining algorithms are employed to

Andrew Kusiak; Anoop Verma

2012-01-01

61

Airfoil characteristics for wind turbines.  

National Technical Information Service (NTIS)

Airfoil characteristics for use in the Blade Element Momentum (BEM) method calculating the forces on Horizontal Axis Wind Turbines (HAWT) are derived by use of systematic methods. The investigation and derivation of the airfoil characteristics are based o...

C. Bak P. Fuglsang N. N. Soerensen H. Aagaard Madsen Wen Zhong Shen

1999-01-01

62

Wind Turbine Manufacturing Process Monitoring.  

National Technical Information Service (NTIS)

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 technica...

C. Nafis C. Yerramalli J. Gangloff P. Simacek S. Advani S. Sinha W. Faidi

2012-01-01

63

Twin Turbine Vortex Wind Mill.  

National Technical Information Service (NTIS)

The twin turbine vortex wind mill consists of a pair of multibladed rotors placed at the ends of a hollow cylindrical cage which is specially designed to produce vortex motion. Both the turbines are coupled to a single vertical shaft from which rotary mec...

M. A. B. Narayanan

1979-01-01

64

Wind and solar powered turbine  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

65

Unavailability of wind turbines due to wind-induced accelerations  

Microsoft Academic Search

The malfunctioning of acceleration-sensitive equipment in wind turbines has the potential to affect their annual failure rates during normal operating conditions. Current protective measures for wind turbines are triggered by wind speed. However, this option neglects the structural response of the wind turbines, and limits the possibility of effectively controlling accelerations at the top of the wind towers. In this

Leonardo Dueñas-Osorio; Biswajit Basu

2008-01-01

66

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

SciTech Connect

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.

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

1984-09-01

67

Airfoils for wind turbine  

DOEpatents

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.

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

2000-01-01

68

RCS measurement of wind turbines  

Microsoft Academic Search

A set of measurements has recently been undertaken in the UK with the aim of determining the RCS (Radar Cross Section) of typical wind turbines, both in an isolated location, and within a wind farm. The measurements made use of a triband channel sounder, employing 10 MChip\\/s PN sequence with off-line correlation. The results from this campaign are presented, with

Richard Rudd; Bal Rhandawa

2009-01-01

69

Improving Wind Turbine Gearbox Reliability  

Microsoft Academic Search

+1 207 326 7148 Summary This paper describes a new research and development initiative to improve gearbox reliability in wind turbines begun at the National Renewable Energy Laboratory (NREL) in Golden, Colorado, USA. The approach involves a collaboration of NREL staff, expert consultants, and partners from the wind energy industry who have an interest in improving gearbox reliability. The membership

W. Musial; S. Butterfield; B. McNiff

70

Foundations for offshore wind turbines.  

PubMed

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

Byrne, B W; Houlsby, G T

2003-12-15

71

Energy 101: Wind Turbines - 2014 Update  

ScienceCinema

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.

None

2014-06-05

72

Dynamics and stability of wind turbine generators  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

73

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.

74

Wind Turbines and Human Health  

PubMed Central

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.

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

2014-01-01

75

Wind turbines and human health.  

PubMed

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

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

2014-01-01

76

Effect of Precipitation on Wind Turbine Performance.  

National Technical Information Service (NTIS)

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...

R. D. Corrigan R. D. Demiglio

1985-01-01

77

Statistical variation of wind turbine fatigue loads.  

National Technical Information Service (NTIS)

The objective of this investigations is to quantify the statistical variation associated with fatigue loads for wind turbines. Based on aeroelastic calculations for a 1.5 MW stall regulated wind turbine, the variation is quantified, and parameters of impo...

K. Thomsen

1998-01-01

78

Vertical axis wind turbine airfoil  

DOEpatents

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.

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

2012-12-18

79

Wind turbine emulator using wind turbine model based on blade element momentum theory  

Microsoft Academic Search

This paper presents the wind turbine emulator using the wind turbine model based on blade element momentum theory. The lift coefficient cl and drag coefficient cd of designed blade shape are calculated with the fluid analysis. Therefore the proposed wind turbine emulator can emulate the new designed windmill without manufacturing. Also the wind turbine model considers the mechanical model and

K. Ohyama; T. Nakashima

2010-01-01

80

The Lebost Wind Turbine experimental program  

Microsoft Academic Search

The Lebost Wind Turbine is unique in two respects: it consists of a vertical axis turbine which is encased in a perforated hemispherical shroud which acts to focus or concentrate ambient wind energy onto the turbine blades; and the turbine's shaft is directly coupled to a water twister\\/heat brake assembly which heats water via direct mechanical agitation; in other words,

G. Miller; M. Hoffert; B. Rugg; D. Corren

1980-01-01

81

Placement of wind turbines using genetic algorithms  

Microsoft Academic Search

A genetic algorithm approach is employed to obtain optimal placement of wind turbines for maximum production capacity while limiting the number of turbines installed and the acreage of land occupied by each wind farm. Specifically, three cases are considered—(a) unidirectional uniform wind, (b) uniform wind with variable direction, and (c) non-uniform wind with variable direction. In Case (a), 600 individuals

S. A. Grady; M. Y. Hussaini; M. M. Abdullah

2005-01-01

82

Dynamics and Stability of Wind Turbine Generators  

Microsoft Academic Search

This paper describes the dynamic and stability properties of wind turbine generators connected to power systems. Both 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

E. N. Hinrichsen; P. J. Nolan

1982-01-01

83

Suggestions for improving wind turbines power curves  

Microsoft Academic Search

The question is usually not whether a wind turbine can be designed to optimise the power production at the site, but rather whether an existing wind turbines with a certain rotor can be modified in order to improve the power production. In this paper the various methods for improving the wind turbines power output were investigated experimentally and theoretically. The

Mohammed G. Khalfallah; Aboelyazied M. Koliub

2007-01-01

84

Economics of Small Wind Turbines  

NSDL National Science Digital Library

This presentation from the Advanced Technology Environmental and Energy Center (ATEEC) includes instructional materials related to small wind turbines as well as lab activities. The overall learning objective is for students to understand the value of economic incentives with regard to residential wind systems. Users must download this resource for viewing, which requires a free log-in. There is no cost to download the item.

2012-10-02

85

Wind turbine testing. Final report  

SciTech Connect

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.

Smith, P.R.

1995-01-01

86

Preview Control for Wind Turbines  

NASA Astrophysics Data System (ADS)

The success of wind power as a renewable energy source depends on its cost of energy. Wind turbine control has attracted much attention in the controls community due to its potential impact on the cost of wind power. However, novel methods in the literature have not transitioned well to industry. This is because the potential cost benefits of these methods are not well understood. There is a need for basic research to address this issue. This thesis is one step toward transitioning of advanced control methods in literature to the industry. Particularly, we aim to understand the limits of performance. The potential performance improvements of the advanced methods should be large enough to justify their cost and complexity. We investigate the optimal trade-offs between multiple turbine performance goals. We also explore the use of a novel wind preview sensor in closed-loop control laws. The impact of this novel sensor on the optimal turbine performance is investigated. The specific contributions of this thesis can be grouped in three categories. First, we present a preliminary, nonlinear optimization based controller design and analysis framework. This framework can simplify the design of the advanced multivariable controllers for nonlinear systems. It can also be used to investigate the optimal design trade-offs between nonlinear performance constraints and objectives. Second, engineering insight is provided into turbine design trade-offs. Third, we provide mathematical tools that quantify the limits of turbine performance in presence of preview wind measurements. Optimization tools that can analyze the trade-off between preview time and operating condition dependent turbine performance objectives are presented. In low wind speeds, our results show that simultaneous power capture improvements and structural load reductions can be obtained. In high wind speeds, a short amount of preview wind information can be used to overcome the fundamental performance limitations imposed by actuator rate constraints. We provide analytical formulas that quantify these preview time requirements and performance limitations. A convex optimization framework is also presented for the analysis of extreme operating conditions that are defined by deterministic wind disturbance trajectories.

Ozdemir, Ahmet Arda

87

Wind Turbine Siting: Wildlife Concerns  

NSDL National Science Digital Library

The Advanced Technology Environmental and Energy Center (ATEEC) provides this document on wildlife concerns in relation to the siting of wind turbines. The material includes individual student activities and a list of web resources intended to help teachers. Users must download this resource for viewing, which requires a free log-in. There is no cost to download the item.

Everhart, Roger; Lawton, Wendy

2012-11-21

88

Small Wind Turbine Testing and Applications Development  

SciTech Connect

Small wind turbines offer a promising alternative for many remote electrical uses where there is a good wind resource. The National Wind Technology Center (NWTC) of the National Renewable Energy Laboratory helps further the role that small turbines can play in supplying remote power needs. The NWTC tests and develops new applications for small turbines. The NWTC also develops components used in conjunction with wind turbines for various applications. This paper describes wind energy research at the NWTC for applications including battery charging stations, water desalination/purification, and health clinics. Development of data acquisition systems and tests on small turbines are also described.

Corbus, D.; Baring-Gould, I.; Drouilhet, S.; Gevorgian, V.; Jimenez, T.; Newcomb, C.; Flowers, L.

1999-09-14

89

Wind farm control: Addressing the aerodynamic interaction among wind turbines  

Microsoft Academic Search

Wind farms help reduce the average wind cost of energy due to many economies of scale compared to individual turbines located far from each other. However, these groupings introduce the problem of aerodynamic interaction among turbines, which can decrease the total energy converted to electricity compared to the same number of isolated turbines operating under the same wind inflow conditions.

Kathryn E. Johnson; Naveen Thomas

2009-01-01

90

3 MW class offshore wind turbine development  

Microsoft Academic Search

This paper introduces the design and development of a 3MW class offshore wind turbine (WinDS3000). The design has been carried out by considering high reliability, availability, maintainability and serviceability (RAMS) for the wind class TC Ia. An integrated drive train design, which has an innovative three stage gearbox, has been introduced to minimize nacelle weight of the wind turbine and

Jiwoong Park; Jeongil Kim; Youngho Shin; Jeonghoon Lee

2010-01-01

91

Innovatory designs for ducted wind turbines  

Microsoft Academic Search

Designs for conventional ducted wind turbines usually include a large inlet for more absorption of the airflow. However, the most efficient solution should be increasing the speed of wind. In this paper, a bucket-shape ducted wind turbine is proposed and studies show that a sucking effect can be produced according to the Bernoulli's principle, and this significantly increases the wind

Ssu-Yuan Hua; Jung-Ho Cheng

2008-01-01

92

Comparison of field and wind tunnel Darrieus wind turbine data  

SciTech Connect

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.

Sheldahl, R.E.

1981-01-01

93

Wind Turbine Drivetrain Test Facility Data Acquisition System.  

National Technical Information Service (NTIS)

The Wind Turbine Drivetrain Test Facility (WTDTF) is a stateof-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...

J. B. McIntosh

2011-01-01

94

Method and apparatus for wind turbine braking  

DOEpatents

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.

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

2009-02-10

95

Aerodynamics of Horizontal Axis Wind Turbines  

Microsoft Academic Search

\\u000a This chapter reviews the aerodynamic characteristics of horizontal axis wind turbines (HAWTs). While the aerodynamics of wind\\u000a turbine are relatively complicated in detail, the fundamental operational principle of a HAWT is that the action of the blowing\\u000a wind produces aerodynamic forces on the turbine blades to rotate them, thereby capturing the kinetic energy contained in the\\u000a wind and converting this

J. Gordon Leishman

96

Fatigue loads on a pitch regulated wind turbine operating in a coastal wind turbine array.  

National Technical Information Service (NTIS)

The objective of this analysis is to improve the foundations for designing wind turbines in wind turbine arrays and wind farms. The analysis is carried out using load measurements on a Vestas/DWT Windane 34 turbine operating in the Kappel wind farm in the...

K. Thomsen H. Bindner T. Friis Pedersen

1994-01-01

97

A Dynamic Wind Turbine Simulator of the Wind Turbine Generator System  

Microsoft Academic Search

To study dynamic performances of wind turbine generator system (WTGS), and to determine the control structures in laboratory. The dynamic torque generated by wind turbine (WT) must be simulated. In there paper, a dynamic wind turbine emulator (WTE) is designed, which consider wind shear and tower shadow effect, and a dynamic torque compensation scheme is also developed to compensate the

Lei Lu; Zhen Xie; Xing Zhang; Shuying Yang; Renxian Cao

2012-01-01

98

Chapter 14: Wind Turbine Control Systems  

SciTech Connect

Wind turbines are complex, nonlinear, dynamic systems forced by gravity, stochastic wind disturbances, and gravitational, centrifugal, and gyroscopic loads. The aerodynamic behavior of wind turbines is nonlinear, unsteady, and complex. Turbine rotors are subjected to a complicated three-dimensional turbulent wind inflow field that drives fatigue loading. Wind turbine modeling is also complex and challenging. Accurate models must contain many degrees of freedom (DOF) to capture the most important dynamic effects. The rotation of the rotor adds complexity to the dynamics modeling. Designs of control algorithms for wind turbines must account for these complexities. Algorithms must capture the most important turbine dynamics without being too complex and unwieldy. Off-the-shelf commercial soft ware is seldom adequate for wind turbine dynamics modeling. Instead, specialized dynamic simulation codes are usually required to model all the important nonlinear effects. As illustrated in Figure 14-1, a wind turbine control system consists of sensors, actuators and a system that ties these elements together. A hardware or software system processes input signals from the sensors and generates output signals for actuators. The main goal of the controller is to modify the operating states of the turbine to maintain safe turbine operation, maximize power, mitigate damaging fatigue loads, and detect fault conditions. A supervisory control system starts and stops the machine, yaws the turbine when there is a significant yaw misalignment, detects fault conditions, and performs emergency shut-downs. Other parts of the controller are intended to maximize power and reduce loads during normal turbine operation.

Wright, A. D.

2009-01-01

99

Modern control design for flexible wind turbines  

Microsoft Academic Search

Control can improve energy capture and reduce dynamic loads in wind turbines. In the 1970s and 1980s wind turbines used classical control designs to regulate power and speed. The methods used, however, were not always successful. These systems often had bandwidths large enough to destabilize low-damped flexible modes leading to high dynamic load fatigue failures. Modern turbines are larger, mounted

Alan Duane Wright

2003-01-01

100

A variable speed wind turbine power control  

Microsoft Academic Search

To optimize the power in a wind turbine, the speed of the turbine should be able to vary with the wind speed. A simple control scheme is proposed that will allow an induction motor to run a turbine at its maximum power coefficient. The control uses a standard V\\/Hz converter and controls the frequency to achieve the desired power at

Andrew Miller; Edward Muljadi; Donald S. Zinger

1997-01-01

101

Review of wind turbine control  

Microsoft Academic Search

The literature on the design of control sysems for medium- and large-scale wind turbine generators is reviewed. The vast majority of relevant literature is concerned with the control of horizontal-axis machines. Emphasis is given to public-utility service machines with power outputs in the range hundreds to thousands of kilowatts. This work was prompted by the need to determine specific objectives

S. A. DE LA SALLE; D. REARDON; W. E. LEITHEAD; M. J. GRlMBLE

1990-01-01

102

WindFloat: A floating foundation for offshore wind turbines  

Microsoft Academic Search

This manuscript summarizes the feasibility study conducted for the WindFloat technology. The WindFloat is a three-legged floating foundation for multimegawatt offshore wind turbines. It is designed to accommodate a wind turbine, 5 MW or larger, on one of the columns of the hull with minimal modifications to the nacelle and rotor. Potential redesign of the tower and of the turbine

Dominique Roddier; Christian Cermelli; Alexia Aubault; Alla Weinstein

2010-01-01

103

Reduced model of DFIGs wind farms using aggregation of wind turbines and equivalent wind  

Microsoft Academic Search

In this paper, a new reduced model of wind farms with doubly-fed induction generators wind turbines is proposed for representing all the wind turbines of a wind farm by one single equivalent wind turbine. The simulation results demonstrate the effectiveness of the proposed reduced model to represent the collective response of a wind farm in the point of common coupling

L. M. Fernandez; C. A. Garcia; J. R. Saenz; F. Jurado

2006-01-01

104

Frequency control and wind turbine technologies  

Microsoft Academic Search

Increasing levels of wind generation has resulted in an urgent need for the assessment of their impact on frequency control of power systems. Whereas increased system inertia is intrinsically linked to the addition of synchronous generation to power systems, due to differing electromechanical characteristics, this inherent link is not present in wind turbine generators. Regardless of wind turbine technology, the

Gillian Lalor; Alan Mullane; Mark O'Malley

2005-01-01

105

Wind turbine performance under icing conditions  

Microsoft Academic Search

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

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

1998-01-01

106

Dynamic models of wind farms with fixed speed wind turbines  

Microsoft Academic Search

The increasing wind power penetration on power systems requires the development of adequate wind farms models for representing the dynamic behaviour of wind farms on power systems. The behaviour of a wind farm can be represented by a detailed model including the modelling of all wind turbines and the wind farm electrical network. But this detailed model presents a high

Luis M. Fernández; José Ramón Saenz; Francisco Jurado

2006-01-01

107

Comparison of variable geometry vertical axis wind turbines with horizontal axis wind turbines.  

National Technical Information Service (NTIS)

This study is a technical and economic comparison of variable geometry vertical axis wind turbines (VGVAWTs) with horizontal axis wind turbines (HAWTs). Major technical advantages claimed for VAWTs are that they are omnidirectional, i.e. they do not need ...

R. A. W. Shock

1990-01-01

108

LES of wind turbine wakes: Evaluation of turbine parameterizations  

Microsoft Academic Search

Large-eddy simulation (LES), coupled with a wind-turbine model, is used to investigate the characteristics of wind turbine wakes in turbulent boundary layers under different thermal stratification conditions. The subgrid-scale (SGS) stress and SGS heat flux are parameterized using scale-dependent Lagrangian dynamic models (Stoll and Porte-Agel, 2006). The turbine-induced lift and drag forces are parameterized using two models: an actuator disk

Fernando Porte-Agel; Yu-Ting Wu; Leonardo Chamorro

2009-01-01

109

Modeling Smart Structure of Wind Turbine Blade  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

110

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

SciTech Connect

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.

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

2012-11-01

111

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

SciTech Connect

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.

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

2012-11-01

112

Darrieus wind-turbine airfoil configurations  

NASA Astrophysics Data System (ADS)

The purpose was to determine what aerodynamic performance improvement, if any, could be achieved by judiciously choosing the airfoil sections for Darrieus wind turbine blades. Ten different airfoils, having thickness to chord ratios of twelve, fifteen and eighteen percent, were investigated. Performance calculations indicated that the NACA 6-series airfoils yield peak power coefficients at least as great as the NACA. Furthermore, the power coefficient-tip speed ratio curves were broader and flatter for the 6-series airfoils. Sample calculations for an NACA 63 sub 2-015 airfoil showed an annual energy output increase of 17 to 27% depending upon rotor solidity, compared to an NACA 0015 airfoil. An attempt was made to account for the flow curvature effects associated with Darrieus turbines by transforming the NACA 63 sub 2-015 airfoil to an appropriate shape.

Migliore, P. G.; Fritschen, J. R.

1982-06-01

113

Designing Drive Trains for the Next Generation of Wind Turbines (FloDesign Wind Turbine Corporation)  

Microsoft Academic Search

Today's wind turbines have nearly reached their maximum possible efficiency and are limited to sites with a narrow profile of wind patterns. The patent-pending Mixer Ejector Wind Turbine (MEWT) concept proposed by FloDesign promises to outperform existing wind turbines by a factor of three or more in a much wider range of wind resources. Olin College’s FloDesign SCOPE team was

Mateen Abdul; Kelcy Adamec; Gavin Boggs; Matthew Crawford; Kevin Sihlanick; Russell Torres

2009-01-01

114

Lightning protection of wind turbines  

NASA Technical Reports Server (NTRS)

Possible damages to wind turbine components due to lightning strikes are discussed and means to prevent the damage are presented. A low resistance path to the ground is noted to be essential for any turbine system, including metal paths on nonmetal blades to conduct the strike. Surge arrestors are necessary to protect against overvoltages both from utility lines in normal operation and against lightning damage to control equipment and contactors in the generator. MOS structures are susceptible to static discharge injury, as are other semiconductor devices, and must be protected by the presence of static protection circuitry. It is recommended that the electronics be analyzed for the circuit transient response to a lightning waveform, to induced and dc current injection, that input/output leads be shielded, everything be grounded, and lightning-resistant components be chosen early in the design phase.

Dodd, C. W.

1982-01-01

115

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

SciTech Connect

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.

van Dam, J.; Jager, D.

2010-02-01

116

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

SciTech Connect

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

None

2010-02-22

117

Aeroacoustics of large wind turbines  

NASA Technical Reports Server (NTRS)

This paper reviews published information on aerodynamically generated noise from large horizontal axis wind turbines operated for electric power generation. Methods are presented for predicting both the discrete frequency rotational noise components and the broadband noise components, and results are compared with measurements. Refraction effects that result in the formation of high-frequency shadow zones in the upwind direction and channeling effects for the low frequencies in the downwind direction are illustrated. Special topics such as distributed source effects in prediction and the role of building dynamics in perception are also included.

Hubbard, Harvey H.; Shepherd, Kevin P.

1991-01-01

118

Microprocessor control of a wind turbine generator  

NASA Technical Reports Server (NTRS)

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.

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

1978-01-01

119

Microprocessor control of a wind turbine generator  

NASA Technical Reports Server (NTRS)

This paper describes a microprocessor based system 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.

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

1978-01-01

120

Sensorless active yaw control for wind turbines  

Microsoft Academic Search

An active yaw control scheme for a horizontal axis wind turbine is proposed. The control strategy is based on measurement of the generated output power, without any wind intensity and\\/or wind direction sensors. Special attention is given to some control parameters to make the yaw driver less sensitive to wind turbulence. Results obtained in the laboratory implementation are presented and

Felix A. Farret; L. L. Pfitscher; Daniel P. Bernardon

2001-01-01

121

Condition monitoring and fault diagnostics of wind turbines  

Microsoft Academic Search

Condition monitoring and fault diagnostics is important for wind turbines to ensure safety and reliability. However, the application in wind turbine is still in initial stage. This paper analyses the frequent faults in wind turbines and determines the sensor configuration of a wind turbine. Architecture of condition monitoring and fault diagnostics system is built to monitor a wind farm. Methodology

Wenxiu Lu; Fulei Chu

2010-01-01

122

Laboratory-scale experiments on wind turbine nacelle movement estimation  

Microsoft Academic Search

The effect of nacelle motion should be considered when calculating the wind speed relative to the wind turbine structure, which is essential in wind turbine control and performance testing. A Kalman filter approach is applied to estimate the nacelle motion of a wind turbine. Information from several accelerometers and strain gauges which are installed on the wind turbine tower is

Yoonsu Nam; Tai Jun Yoon

2009-01-01

123

SMALL WIND TURBINE TESTING: INDOOR AND OUTDOOR METHODOLOGIES  

Microsoft Academic Search

This paper describes the methodology to obtain the power curve of Small Wind Turbine Generators (SWTG) in field and in the laboratory. A system includes a wind turbine, data logger and transducers with capacity of measuring the instantaneous power of the wind turbine for different wind speed. Three wind turbines was tested in laboratory with the blades using fluid flow

Pontifical Catholic; Jorge Antonio

124

AN AEROACOUSTIC ANALYSIS OF WIND TURBINES  

Microsoft Academic Search

This paper describes 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 are being considered. These are airfoil self-noise, the effects of blade rotation, and the propagation of sound over large distances. Two aspects of airfoil

Philip J. Morris; Lyle N. Long; Kenneth S. Brentner

2004-01-01

125

Dynamic stall on wind turbine blades  

Microsoft Academic Search

Dynamic loads must be predicted accurately in order to estimate the fatigue life of wind turbines operating in turbulent environments. Dynamic stall contributes to increased dynamic loads during normal operation of all types of horizontal-axis wind turbine (HAWTs). This report illustrates how dynamic stall varies throughout the blade span of a 10 m HAWT during yawed and unyawed operating conditions.

C. P. Butterfield; D. Simms; G. Scott; A. C. Hansen

1991-01-01

126

An integrated modeling method for wind turbines  

Microsoft Academic Search

To study the interaction of the electrical, mechanical, and aerodynamic aspects of a wind turbine, a detailed model that considers all these aspects must be used. A drawback of many studies in the area of wind turbine simulation is that either a very simple mechanical model is used with a detailed electrical model, or vice versa. Hence the interactions between

Roohollah Fadaeinedjad

2008-01-01

127

Wind turbine value analysis for electric utilities  

Microsoft Academic Search

A methodology for the analysis of the value of large-scale wind turbines to electric utilities, and its application to utility, socioeconomic and meteorological data in two case studies is described. The value analysis was carried out for the year of reference 1985 and included different levels of wind turbine penetration. Results of the value analysis are given. The utility planning

W. Dub

1982-01-01

128

Multimode control system for wind turbines  

Microsoft Academic Search

A multi-mode electronic wind turbine control system establishes a reference blade angle for a two-bladed, horizontal axis, variable pitch wind turbine rotor, the blade angle being regulated by a hydraulic pitch change mechanism. The rotor, via appropriate shafts and a gearbox, is coupled to a synchronous generator to produce electrical energy which is fed to a power utility grid. The

K. I. Harner; J. M. Kos; J. P. Patrick

1980-01-01

129

Design evolution of large wind turbine generators  

NASA Technical Reports Server (NTRS)

During the past five years, the goals of economy and reliability have led to a significant evolution in the basic design--both external and internal--of large wind turbine systems. To show the scope and nature of recent changes in wind turbine designs, development of three types are described: (1) system configuration developments; (2) computer code developments; and (3) blade technology developments.

Spera, D. A.

1979-01-01

130

CFD MODELLING OF WIND TURBINE AIRFOIL AERODYNAMICS  

Microsoft Academic Search

SUMMARY This paper reports the first findings of an ongoing research programme on wind turbine computational aerodynamics at the University of Glasgow. Several modeling aspects of wind turbine airfoil aerodynamics based on the solution of the Reynolds- averaged Navier-Stokes (RANS) equations are addressed. One of these is the effect of an a priori method for structured grid adaptation aimed at

M. S. Campobasso; A. Zanon; M. Foerster; F. Fraysse; A. Bonfiglioli

131

Multifunctional nanocomposite coating for wind turbine blades  

Microsoft Academic Search

In this study, multifunctional carbon nanofiber (CNF) paper-based nanocomposite coating was developed for wind turbine blades. The importance of vibration damping in relation to structural stability, dynamic response, position control, and durability of wind turbine blades cannot be underestimated. The vibration damping properties of the nanocomposite blades were significantly improved and the damping ratio of the nanocomposite increased by 300%

Fei Liang; Jihua Gou; Jay Kapat; Haichang Gu; Gangbing Song

2011-01-01

132

Optical Motion Analysis of Wind Turbines.  

National Technical Information Service (NTIS)

The study reported in this paper is aimed at discovering the pros and cons of optical motion analysis of large wind turbines. A state of the art optical motion analysis technique was applied for the first time to a wind turbine of 10(m) diameter. Two vide...

G. P. Corten J. C. Sabel

1995-01-01

133

Wind turbine modeling using the bond graph  

Microsoft Academic Search

This paper addresses the problem of bond graph methodology as a graphical approach for modeling wind turbine systems. In this case, we consider the modeling of a wind turbine system with individual pitch control scheme and the interaction with tower motions. Two different bond graph models are presented, one complex and one simplified. Furthermore, the purpose of this paper is

Tore Bakka; Hamid Reza Karimi

2011-01-01

134

Simulation investigation of wind turbine imbalance faults  

Microsoft Academic Search

This paper investigates the use of simulations to study wind turbine imbalance faults. The dynamics of a model wind turbine generator (WTG) are simulated in a combined environment of TurbSim, FAST (Fatigue, Aerodynamics, Structures, Turbulence), and Simulink in three different scenarios, i.e., normal operating conditions, blade imbalance, and aerodynamic asymmetry. The blade imbalance is simulated by scaling the mass density

Xiang Gong; Wei Qiao

2010-01-01

135

Lightning protection system for a wind turbine  

DOEpatents

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).

Costin, Daniel P. (Chelsea, VT) [Chelsea, VT; Petter, Jeffrey K. (Williston, VT) [Williston, VT

2008-05-27

136

Certification testing for small wind turbines  

SciTech Connect

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.

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

1999-10-20

137

Smart structure for small wind turbine blade  

NASA Astrophysics Data System (ADS)

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.

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

2013-08-01

138

Economics of large wind turbine generators  

SciTech Connect

This study demonstrates that established utility system planning methods are applicable to studying wind turbine generators, with minor modifications. A total utility cost approach was used to evaluate the economics of wind turbine generators. The limitations of the busbar energy cost method rule out its use. Three analytic models are studied: the wind plant performance model, the generation system reliability model, and the generation system production cost model. The results of generation, transmission, and distribution studies are interpreted. The results are then integrated to give a single measure of the value of distributed wind turbines. These results demonstrate that the value of distributed wind turbines is dominated by the generation energy and capacity value. The quality and availability of the wind resource far outweighs credits achievable from an optimal electrical location.

Oplinger, J.L.

1982-06-01

139

Wind turbine aerodynamics and loads control in wind shear flow  

Microsoft Academic Search

Wind turbine is subjected to some asymmetrical effects like wind shear, which will lead to unsteady blade airloads and performance. Fatigue loads can lead to damage of turbine components and eventually to failures. It is evident that the variation of the velocity over the rotor disc has an influence on the blade and introduces both flap-wise and edge-wise fatigue damage

Xin Shen; Xiaocheng Zhu; Zhaohui Du

2011-01-01

140

Modeling Smart Structure of Wind Turbine Blade  

Microsoft Academic Search

With the increasing size of wind turbine blades, the need for more sophisticated load control techniques has induced the interest\\u000a for aerodynamic control systems with build-in intelligence on the blades. The paper aims to provide a way for modeling the\\u000a adaptive wind turbine blades and analyze its ability for vibration suppress. It consists of the modeling of the adaptive wind

Yin-Hu Qiao; Jiang Han; Chun-Yan Zhang; Jie-Ping Chen

2011-01-01

141

Development of the Risø wind turbine airfoils  

Microsoft Academic Search

This paper presents the wind turbine airfoil development at Risø. The design method is described together with our target characteristics for wind turbine airfoils. The use of the CFD code Ellipsys2D for prediction of final target characteristics is described together with the VELUX wind tunnel testing setup. Three airfoil families were developed; Risø-A1, Risø-P and Risø-B1. The Risø-A1 airfoil family

Peter Fuglsang; Christian Bak

2004-01-01

142

Wind Turbine Performance Under Icing Conditions  

Microsoft Academic Search

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

William J. Jasinski; Urbana Shawn; C. Noe

1998-01-01

143

Aerodynamic response analysis of wind turbines  

Microsoft Academic Search

Wind energy has received increasing attention in the same way as energy crisis and environmental deterioration. The aerodynamic\\u000a response of wind turbines is the major problem in wind turbine design. Blade element momentum theory was used to study the\\u000a aerodynamic thrusts of the blades on the tower. Iterative solutions were used to calculate the axial flow induction factor\\u000a for each

Jing Li; Jianyun Chen; Xiaobo Chen

2011-01-01

144

Wind turbine control system modeling capabilities  

SciTech Connect

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.

Pierce, K.; Fingersh, L.J.

1998-04-01

145

Assessment of wind characteristics and wind turbine characteristics in Taiwan  

Microsoft Academic Search

Wind characteristics and wind turbine characteristics in Taiwan have been thoughtfully analyzed based on a long-term measured data source (1961–1999) of hourly mean wind speed at 25 meteorological stations across Taiwan. A two-stage procedure for estimating wind resource is proposed. The yearly wind speed distribution and wind power density for the entire Taiwan is firstly evaluated to provide annually spatial

Tsang-Jung Chang; Yu-Ting Wu; Hua-Yi Hsu; Chia-Ren Chu; Chun-Min Liao

2003-01-01

146

Large-scale wind turbine structures  

NASA Astrophysics Data System (ADS)

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.

Spera, David A.

1988-05-01

147

Darrieus wind-turbine airfoil configurations  

SciTech Connect

The purpose of this study was to determine what aerodynamic performance improvement, if any, could be achieved by judiciously choosing the airfoil sections for Darrieus wind turbine blades. Analysis was limited to machines using two blades of infinite aspect ratio, having rotor solidites from seven to twenty-one percent, and operating at maximum Reynolds numbers of approximately three million. Ten different airfoils, having thickness to chord ratios of twelve, fifteen and eighteen percent, were investigated. Performance calculations indicated that the NACA 6-series airfoils yield peak power coefficients at least as great as the NACA four-digit airfoils which have historically been chosen for Darrieus turbines. Furthermore, the power coefficient-tip speed ratio curves were broader and flatter for the 6-series airfoils. Sample calculations for an NACA 63/sub 2/-015 airfoil showed an annual energy output increase of 17 to 27% depending upon rotor solidity, compared to an NACA 0015 airfoil. An attempt was made to account for the flow curvature effects associated with Darrieus turbines by transforming the NACA 63/sub 2/-015 airfoil to an appropriate shape.

Migliore, P.G.; Fritschen, J.R.

1982-06-01

148

A stochastic DEVS wind turbine component model for wind farm simulation  

Microsoft Academic Search

Wind farms use several wind turbines to generate electricity and provide a renewable source of energy. However, due to large forces as a result of hourly and seasonal variations in wind speed and direction, wind turbines experience stochastic loading that often lead to failures of wind turbine components such as the gearbox and generator. Wind turbine failures result in costly

Eduardo Pérez; Lewis Ntaimo; Eunshin Byon; Yu Ding

2010-01-01

149

Development of wind turbine towers using fiber reinforced polymers  

Microsoft Academic Search

With an ongoing trend in the wind turbine market, the size of wind turbines has been increasing continuously. Larger wind turbines imply an increase in size, weight, and loads acting on the wind turbine tower. This requires towers to be stronger and stiffer, and consequently leads to bigger tower diameters. Because of their size and weight, transportation and erection require

Nibong Ungkurapinan

2005-01-01

150

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

Microsoft Academic Search

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

Walford; Christopher A

2006-01-01

151

Effect of precipitation on wind turbine performance  

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

152

Active load control techniques for wind turbines.  

SciTech Connect

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.

van Dam, C.P. (University of California, Davis, CA); Berg, Dale E.; Johnson, Scott J. (University of California, Davis, CA)

2008-07-01

153

Stability Simulation of Wind Turbine Systems  

Microsoft Academic Search

A simulation and digital computer modeling effort is described in which a wind turbine-generator system is adapted for stability evaluation using a large scale transient stability computer program. Component models of the MOD-2 wind generator system are described and their digital model equations are provided. A versatile wind velocity model is described, which provides the capability of simulating a wide

P. M. Anderson; Anjan Bose

1983-01-01

154

A Copula Model of Wind Turbine Performance  

Microsoft Academic Search

The conventional means of assessing the perfor- mance of a wind turbine is through consideration of its power curve which provides the relationship between power output and measured wind speed. In this letter, it is shown how the joint probability distribution of power and wind speed can be learned from data, rather than from examination of the implied function of

Bruce Stephen; Stuart J. Galloway; David McMillan; David C. Hill; David G. Infield

2011-01-01

155

Stochastic wind turbine control in multiblade coordinates  

Microsoft Academic Search

In this paper we consider wind turbine load attenuation through model based control. Asymmetric loads caused by the wind field can be reduced by pitching the blades individually. To this end we investigate the use of stochastic models of the wind which can be included in a model based individual pitch controller design. In this way the variability of the

Sven Creutz Thomsen; Henrik Niemann; Niels Kjølstad Poulsen

2010-01-01

156

Wake measurements around operating wind turbines  

SciTech Connect

Researchers at Oregon State University have conducted wind measurement programs to describe the wake behind large horizontal axis turbines at Goodnoe Hills, Washington, (MOD-2), and behind the FloWind vertical axis wind turbine near Ellenburg, Washington. Wake measurements were taken using portable kite anemometers as well as fixed place anemometers under several atmospheric stability conditions and turbine operating conditions. Centerline hub height (midrotor) measurements were taken downwind and crosswind from 3-9 diameters. These wake programs are discussed and the velocity deficits measured are compared to the estimated deficits calculated from wake models.

Baker, R.W.; Katen, P.C.; Walker, S.N.

1985-05-01

157

PowerJet Wind Turbine Project  

SciTech Connect

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

Bartlett, Raymond J

2008-11-30

158

Wind technology development: Large and small turbines  

NASA Astrophysics Data System (ADS)

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.

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

1994-12-01

159

Nonlinear control of variable speed wind turbines for power regulation  

Microsoft Academic Search

A nonlinear controller has been designed for variable speed wind turbines electric power regulation. The efficiency and reliability of wind power is shown to be depending on the applied control strategy of the wind turbine. Up to now, classical regulation is implemented only. However, under sudden wind profile variations, the wind turbine performance decrease which may cause troubles in the

Boubekeur Boukhezzar; Houria Siguerdidjane

2005-01-01

160

A new structure based on cascaded multilevel converter for variable speed wind turbine  

Microsoft Academic Search

An alternative structure for variable speed wind turbine, using multiple permanent magnet synchronous generators (PMSGs) drive-train configuration and cascaded multilevel converter is proposed in this paper. This study presents a power electronic solution for the wind turbine. A transformer-less cascaded multilevel converter interface based on PMSGs is developed to synthesize a desired high ac sinusoidal output voltage. The benefits of

Fujin Deng; Zhe Chen

2010-01-01

161

Diffuser for augmenting a wind turbine  

DOEpatents

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.

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

1984-01-01

162

Wind Turbine Test Micon 55 KW.  

National Technical Information Service (NTIS)

The report describes standard measurements performed on a Micon 55 kW wind turbine. The measurements carried out and reported here comprises the power output, system efficiency, energy production, transmission efficiency, rotor power, rotor efficiency, st...

T. Friis Pedersen

1986-01-01

163

Wind Turbine Test Danwin 23 Prototype.  

National Technical Information Service (NTIS)

The report describes standard measurements performed on a Danwin 23 180 kW prototype wind turbine. The measurements carried out and reported here comprises the power output, system efficiency, energy production, transmission efficiency, rotor power, rotor...

T. Friis Pedersen S. Markkilde Petersen U. Schmidt Paulsen P. Voelund

1988-01-01

164

Darrieus Wind-Turbine Airfoil Configurations.  

National Technical Information Service (NTIS)

The purpose of this study was to determine what aerodynamic performance improvement, if any, could be achieved by judiciously choosing the airfoil sections for Darrieus wind turbine blades. Analysis was limited to machines using two blades of infinite asp...

P. G. Migliore J. R. Fritschen

1982-01-01

165

Vertical Axis Wind Turbine Foundation parameter study  

SciTech Connect

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.

Lodde, P.F.

1980-07-01

166

Dynamically Reconfigurable Wind Turbine Blade Assembly.  

National Technical Information Service (NTIS)

A dynamically reconfigurable wind turbine blade assembly includes a plurality of reconfigurable blades mounted on a hub, an actuator fixed to each of the blades and adapted to effect the reconfiguration thereof, and an actuator power regulator for regulat...

C. H. Beauchamp S. A. Huyer S. J. Plunkett

2002-01-01

167

Fatigue reliability of wind turbine components.  

National Technical Information Service (NTIS)

Fatigue life estimates for wind turbine components can be extremely variable due to both inherently random and uncertain parameters. A structural reliability analysis is used to qualify the probability that the fatigue life will fall short of a selected t...

P. S. Veers

1990-01-01

168

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

SciTech Connect

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.

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

2010-01-01

169

Wind direction change criteria for wind turbine design  

Microsoft Academic Search

A method is presented for estimating the root mean square (rms) value of the wind direction change, Delta Theta (tau) = theta (tau + tau) - Theta (tau), that occurs over the swept area of wind turbine rotor systems. An equation is also given for the rms value of the wind direction change that occurs at a single point in

W. C. Cliff

1979-01-01

170

Mars Technologies Spawn Durable Wind Turbines.  

National Technical Information Service (NTIS)

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-...

2014-01-01

171

Computational studies of horizontal axis wind turbines  

Microsoft Academic Search

A numerical technique has been developed for efficiently simulating fully three-dimensional viscous fluid flow around horizontal axis wind turbines (HAWT) using a zonal approach. The flow field is viewed as a combination of viscous regions, inviscid regions and vortices. The method solves the costly unsteady Reynolds averaged Navier-Stokes (RANS) equations only in the viscous region around the turbine blades. It

Guanpeng Xu

2001-01-01

172

Modeling stochastic wind loads on vertical axis wind turbines  

NASA Astrophysics Data System (ADS)

The Vertical Axis Wind Turbine (VAWT) is a machine which extracts energy from the wind. Since random turbulence is always present, the effect of this turbulence on the wind turbine fatigue life must be evaluated. This problem is approached by numerically simulating the turbulence and calculating, in the time domain, the aerodynamic loads on the turbine blades. These loads are reduced to the form of power and cross spectral densities which can be used in standard linear structural analysis codes. The relative importance of the turbulence on blade loads is determined.

Veers, P. S.

173

Passively cooled direct drive wind turbine  

DOEpatents

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.

Costin, Daniel P. (Chelsea, VT)

2008-03-18

174

Mod2 wind turbine field operations experience  

Microsoft Academic Search

The Mod-2 wind turbine is now in a 2-year research\\/experimental operations phase which offers a unique opportunity to study the effects of single and multiple wind turbines interacting with each other, the power grid, and the environment. This paper addresses the field operations and research testing experienced at the Mod-2 Cluster Goodnoe Hills Research Test Site near Goldendale, WA. Field

L. H. Gordon

1984-01-01

175

Wind Turbine Reliability: Understanding and Minimizing Wind Turbine Operation and Maintenance Costs.  

National Technical Information Service (NTIS)

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 ...

C. A. Walford

2006-01-01

176

Site calibration for the wind turbine performance evaluation  

Microsoft Academic Search

The accurate wind speed information at the hub height of a wind turbine is very essential to the exact estimation of the wind\\u000a turbine power performance testing. Several methods on the site calibration, which is a technique to estimate the wind speed\\u000a at the wind turbine’s hub height based on the measured wind data using a reference meteorological mast, are

Yoonsu Nam; Neungsoo Yoo; Jungwan Lee

2004-01-01

177

Wind tunnel study on wind and turbulence intensity profiles in wind turbine wake  

Microsoft Academic Search

In recent years, there has been a rapid development of the wind farms in Japan. It becomes very important to investigate the\\u000a wind turbine arrangement in wind farm, in order that the wake of one wind turbine does not to interfere with the flow in other\\u000a wind turbines. In such a case, in order to achieve the highest possible efficiency

Takao Maeda; Yasunari Kamada; Junsuke Murata; Sayaka Yonekura; Takafumi Ito; Atsushi Okawa; Tetsuya Kogaki

2011-01-01

178

Control of wind turbines: Past, present, and future  

Microsoft Academic Search

We review the objectives and techniques used in the control of horizontal axis wind turbines at the individual turbine level, where controls are applied to the turbine blade pitch and generator. The turbine system is modeled as a flexible structure operating in the presence of turbulent wind disturbances. Some overview of the various stages of turbine operation and control strategies

Jason H. Laks; Lucy Y. Pao; Alan D. Wright

2009-01-01

179

Vertical axis wind turbine designed aerodynamically at Tokai University  

Microsoft Academic Search

The advantages of the vertical axis wind turbine over conventional propeller-type wind turbines are listed, among them the fact that the turbine is free from the gyroscopic loading accompanied by wind direction tracking. Special attention is given to the straight-wing type vertical axis turbine, which is thought to be particularly advantageous. Also discussed are the characteristics of the blade. It

Y. Kato; K. Seki; Y. Shimizu

1981-01-01

180

Nation's tallest VAWT (Vertical Axis Wind Turbine) turning out the watts. [Vertical Axis Wind Turbine  

Microsoft Academic Search

This article describes the development of the tallest and most powerful windmill of its kind in the U.S. Known as a Vertical Axis Wind Turbine (VAWT), the machine is meant for testing new concepts in vertical axis turbine design. As part of its overall testing program, the turbine will supply electricity to automated water pumps used in irrigation research at

1988-01-01

181

Infrasound emission generated by wind turbines  

NASA Astrophysics Data System (ADS)

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.

Ceranna, Lars; Pilger, Christoph

2014-05-01

182

Jet spoiler arrangement for wind turbine  

DOEpatents

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.

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

1983-09-15

183

Jet spoiler arrangement for wind turbine  

DOEpatents

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.

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

1985-01-01

184

Vertical axis wind turbine control strategy  

SciTech Connect

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.

McNerney, G.M.

1981-08-01

185

On the power regulation of small wind turbines based on experience with small Danish wind turbines  

Microsoft Academic Search

The state of development of the small wind turbines on the Danish market covering a range of 10 to 55 kW, of which approximately 500 are in operation is discussed. A typical feature of Danish small wind turbines is the regulation of the power output by stalling of the rotor blades. The merits of the stall regulation are discussed with

P. Lundsager

1981-01-01

186

Innovative wind turbines. Circulation controlled vertical axis wind turbine. Progress report, March 1December 31, 1976  

Microsoft Academic Search

Theoretical and experimental research efforts in evaluating an innovative concept for vertical axis wind turbines (VAWT) are described. The concept is that of using straight blades composed of circulation controlled airfoil sections. The theoretical analysis has been developed to determine the unsteady lift and moment characteristics of multiple-blade cross-flow wind turbines. To determine the drag data needed as input to

R. E. Walters; J. B. Fanucci; P. W. Hill; P. G. Migliore; W. Squire; T. L. Waltz

1978-01-01

187

Power electronics converters for wind turbine systems  

Microsoft Academic Search

The steady growth of installed wind power which reached 200 GW capacity in 2010, together with the up-scaling of the single wind turbine power capability - 7 MW's has been announced by manufacturers - has pushed the research and development of power converters towards full scale power conversion, lowered cost pr kW, and increased power density and the need for

F. Blaabjerg; M. Liserre; K. Ma

2011-01-01

188

Wear Analysis of Wind Turbine Gearbox Bearings  

Microsoft Academic Search

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

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

2010-01-01

189

Multilevel converters for 10 MW Wind Turbines  

Microsoft Academic Search

Several promising multi-level converter configurations for 10 MW Wind Turbines both with direct drive and one-stage gear box drive using Permanent Magnet Synchronous Generator (PMSG) are proposed, designed and compared. Reliability is a crucial indicator for large scale wind power converters, therefore the evaluations are mainly focused on the power device thermal performances, which are closely related to the life

Ke Ma; Frede Blaabjerg

2011-01-01

190

A review of large wind turbine systems  

Microsoft Academic Search

Research areas in the design and operation of large wind turbines in the U.S. and Europe are detailed, with attention given to current and completed programs. Theoretical work in the U.S. is focused on aerodynamics of blades, structural dynamics, control systems, and safety through safe life design, redundancy, and quality assurance. Work is continuing on wind characteristics over the rotor

H. Selzer; J. I. Lerner

1983-01-01

191

COMPOSITE MATERIALS FOR INNOVATIVE WIND TURBINE BLADES  

Microsoft Academic Search

The Wind Energy Technology Department at Sandia National Laboratories (SNL) focuses on producing innovations in wind turbine blade technology to enable the development of longer blades that are lighter, more structurally and aerodynamically efficient, and impart reduced loads to the system. A large part of the effort is to characterize the properties of relevant composite materials built with typical manufacturing

Thomas D. Ashwill; Joshua A. Paquette

192

Radar signature control of wind turbine generators  

Microsoft Academic Search

Many of the prime locations for wind farms in the UK are on exposed landscapes close to regional airports. However, planning permission for such installations is often being denied because the moving blades of the wind turbines interfere with the operation of airport radar systems. Airport surveillance radars track the position and speed of aircraft in their surrounding airspace using

A. Tennant; B. Chambers

2005-01-01

193

A sensorless control for wind turbine  

Microsoft Academic Search

This paper presents a sensorless control for a stall regulated variable speed wind turbine, where the speed reference is obtained from the estimated aerodynamic torque. The LQG\\/LTR methodology is applied to the design of an optimal discrete-time feedback controller for a Wind Energy Conversion System, aiming to maximize the efficiency on energy conversion and to minimize the detrimental dynamic loads

Ronilson Rocha

2009-01-01

194

Dynamic Characterization Testing of Wind Turbines.  

National Technical Information Service (NTIS)

The U.S. Department of Energy (DOE), in conjunction with the U.S. wind industry, is supporting the development and commercialization of utility-grade wind turbines. Under the Certification Program, the DOE, through the National Renewable Energy Laboratory...

R. Osgood

2001-01-01

195

Practical aspects for small wind turbine applications  

Microsoft Academic Search

SUMMARY Low power wind turbines (WTs) are less widely applied compared to medium and high power systems. These WTs are suitable for decentralized applications and can provide electricity to residential buildings, hotels, greenhouses, etc. These WTs can be of horizontal or vertical rotor axis, must be of low cut-in wind speed and flexible in installation and operation, considering their limits

Y. Tripanagnostopoulos; A. Christodoulou; S. Tselepis; M. Souliotis; J. K. Tonui

196

Technical Description of the NIBE Wind Turbines.  

National Technical Information Service (NTIS)

As part of the wind power programme of the Danish Ministry of Energy and the electric utilities two wind turbines have been constructed and placed at Nibe Bredning in North Jutland. This technical description has been made to give a total survey of the co...

1981-01-01

197

Research and development for shrouded wind turbines  

Microsoft Academic Search

A special shroud, designed for enclosing a wind turbine in order to exploit wind power as economically as possible, is presented. Several geometries, including the short diffuser shroud and the circular wing shroud, are discussed, and it is shown that a significant power augmentation can be achieved with a fairly compact shroud. Up to an 80% improvement in the shroud

O. Igra

1981-01-01

198

Tailored Airfoils for Vertical Axis Wind Turbines.  

National Technical Information Service (NTIS)

The evolution of a family of airfoil sections designed to be used as blade elements of a vertical axis wind turbine (VAWT) is described. This evolution consists of extensive computer simulation, wind tunnel testing and field testing. The process reveals t...

P. C. Klimas

1984-01-01

199

Subhourly wind forecasting techniques for wind turbine operations  

SciTech Connect

Three models for making automated forecasts of subhourly wind and wind power fluctuations were examined to determine the models' appropriateness, accuracy, and reliability in wind forecasting for wind turbine operation. Such automated forecasts appear to have value not only in wind turbine control and operating strategies, but also in improving individual wind turbine control and operating strategies, but also in improving individual wind turbine operating strategies (such as determining when to attempt startup). A simple persistence model, an autoregressive model, and a generalized equivalent Markhov (GEM) model were developed and tested using spring season data from the WKY television tower located near Oklahoma City, Oklahoma. The three models represent a pure measurement approach, a pure statistical method and a statistical-dynamical model, respectively. Forecasting models of wind speed means and measures of deviations about the mean were developed and tested for all three forecasting techniques for the 45-meter level and for the 10-, 30- and 60-minute time intervals. The results of this exploratory study indicate that a persistence-based approach, using onsite measurements, will probably be superior in the 10-minute time frame. The GEM model appears to have the most potential in 30-minute and longer time frames, particularly when forecasting wind speed fluctuations. However, several improvements to the GEM model are suggested. In comparison to the other models, the autoregressive model performed poorly at all time frames; but, it is recommended that this model be upgraded to an autoregressive moving average (ARMA or ARIMA) model. The primary constraint in adapting the forecasting models to the production of wind turbine cluster power output forecasts is the lack of either actual data, or suitable models, for simulating wind turbine cluster performance.

Wegley, H.L.; Kosorok, M.R.; Formica, W.J.

1984-08-01

200

Evaluation of micro-wind turbine aerodynamics, wind speed sampling interval and its spatial variation  

Microsoft Academic Search

Large wind turbines are usually installed in areas where wind speed distributions have been observed long enough to make sure of their high efficiency. However, micro-wind turbines are mostly used in areas where wind conditions are not necessarily favourable for efficient power production. Therefore, micro-wind turbines require specific designs to work effectively in low and turbulent wind resource areas. However,

A. Makkawi; AN Celik; T. Muneer

2009-01-01

201

Voltage grid support of DFIG wind turbines during grid faults  

Microsoft Academic Search

The fault ride-through and grid support capabilities of the doubly fed induction generator (DFIG) wind turbines address primarily the design of DFIG wind turbine control with special focus on power converters protection and on voltage control issues. This paper presents the design of a voltage control strategy for DFIG wind turbines, which enhances the fault ride-through capability of DFIG wind

Anca D. Hansen; Gabriele Michalke

202

Modeling the effects of wind turbines on radar returns  

Microsoft Academic Search

Wind turbines located near radar installations can significantly interfere with a radar's ability to detect its intended targets. In order to better understand and mitigate the adverse effects of wind turbines on radar, the government and wind farm community need tools that can be used to analyze the radar returns from wind turbines. Remcom's XGtd® software is a high frequency

R. Ryan Ohs; Gregory J. Skidmore; Gary Bedrosian

2010-01-01

203

Grid integration impacts on wind turbine design and development  

Microsoft Academic Search

This paper presents an overall perspective on contemporary issues like wind power plants and grid integration. The purpose is to present and discuss the impacts of emerging new grid connection requirements on modern wind turbines. The grid integration issue has caused several new challenges to the wind turbine design and development. The survival of different wind turbine concepts and controls

A. D. Hansen; N. A. Cutululis; P. Sorensen; F. Iov

2009-01-01

204

Optimization of Wind Turbine Performance With Data-Driven Models  

Microsoft Academic Search

This paper presents a multiobjective optimization model of wind turbine performance. Three different objectives, wind power output, vibration of drive train, and vibration of tower, are used to evaluate the wind turbine performance. Neural network models are developed to capture dynamic equations modeling wind turbine performance. Due to the complexity and nonlinearity of these models, an evolutionary strategy algorithm is

Andrew Kusiak; Zijun Zhang; Mingyang Li

2010-01-01

205

LES of wind turbine wakes: Evaluation of turbine parameterizations  

NASA Astrophysics Data System (ADS)

Large-eddy simulation (LES), coupled with a wind-turbine model, is used to investigate the characteristics of wind turbine wakes in turbulent boundary layers under different thermal stratification conditions. The subgrid-scale (SGS) stress and SGS heat flux are parameterized using scale-dependent Lagrangian dynamic models (Stoll and Porte-Agel, 2006). The turbine-induced lift and drag forces are parameterized using two models: an actuator disk model (ADM) that distributes the force loading on the rotor disk; and an actuator line model (ALM) that distributes the forces on lines that follow the position of the blades. Simulation results are compared to wind-tunnel measurements collected with hot-wire and cold-wire anemometry in the wake of a miniature 3-blade wind turbine at the St. Anthony Falls Laboratory atmospheric boundary layer wind tunnel. In general, the characteristics of the wakes simulated with the proposed LES framework are in good agreement with the measurements. The ALM is better able to capture vortical structures induced by the blades in the near-wake region. Our results also show that the scale-dependent Lagrangian dynamic SGS models are able to account, without tuning, for the effects of local shear and flow anisotropy on the distribution of the SGS model coefficients.

Porte-Agel, Fernando; Wu, Yu-Ting; Chamorro, Leonardo

2009-11-01

206

Load attenuating passively adaptive wind turbine blade  

DOEpatents

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.

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

2003-01-01

207

Active robust control of wind turbines  

NASA Astrophysics Data System (ADS)

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.

Rezaei, Vahid

208

Wind tunnel study on wind and turbulence intensity profiles in wind turbine wake  

NASA Astrophysics Data System (ADS)

In recent years, there has been a rapid development of the wind farms in Japan. It becomes very important to investigate the wind turbine arrangement in wind farm, in order that the wake of one wind turbine does not to interfere with the flow in other wind turbines. In such a case, in order to achieve the highest possible efficiency from the wind, and to install as many as possible wind turbines within a limited area, it becomes a necessity to study the mutual interference of the wake developed by wind turbines. However, there is no report related to the effect of the turbulence intensity of the external flow on the wake behind a wind turbine generated in the wind tunnel. In this paper, the measurement results of the averaged wind profile and turbulence intensity profile in the wake in the wind tunnel are shown when the turbulence intensity of the external wind was changed. The wind tunnel experiment is performed with 500mm-diameter two-bladed horizontal axis wind turbine and the wind velocity in wake is measured by an I-type hot wire probe. As a result, it is clarified that high turbulence intensities enable to the entrainment of the main flow and the wake and to recover quickly the velocity in the wake.

Maeda, Takao; Kamada, Yasunari; Murata, Junsuke; Yonekura, Sayaka; Ito, Takafumi; Okawa, Atsushi; Kogaki, Tetsuya

2011-06-01

209

Wind Turbine Test. Wind Matic WM 17S.  

National Technical Information Service (NTIS)

The report describes standard measurements performed on a Wind-Matic WM 17S, 75 kW wind turbine. The measurements carried out and reported here comprises the power output, system efficiency, energy production, transmission efficiency, rotor power, rotor e...

T. Friis Pedersen

1986-01-01

210

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

SciTech Connect

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.

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

2010-02-01

211

A review of large wind turbine systems  

NASA Astrophysics Data System (ADS)

Research areas in the design and operation of large wind turbines in the U.S. and Europe are detailed, with attention given to current and completed programs. Theoretical work in the U.S. is focused on aerodynamics of blades, structural dynamics, control systems, and safety through safe life design, redundancy, and quality assurance. Work is continuing on wind characteristics over the rotor disk and design criteria with regard to cost/benefits and tradeoffs involving various configurations and materials for the rotor blades, placement, pitch control, blade articulation, the tower, the drive train, the gear box, a quill shaft, generator type, and reliability and maintenance. Costing models are being developed. Test experience has been gained through the manufacture and operation of the five Mod 0A, one Mod-1, four Mod-2, and one WTS-4 wind turbines. The European work on blade loading, wind turbine dimensioning, materials, wind structure, environmental impacts, and economics are reviewed, together with the operational experience with the Gedser, two Nibe, the Tvind, and Growian machines. Several countries are also testing smaller wind turbines manufactured indigenously or imported.

Selzer, H.; Lerner, J. I.

212

Mod2 wind turbine field operations experiment  

Microsoft Academic Search

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

L. H. Gordon

1985-01-01

213

Mod2 wind turbine field operations experience  

Microsoft Academic Search

The three-machine, 7.5 MW Goodnoe Hills cluster, located near Goldendale, Washington, 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

1985-01-01

214

Mars Technologies Spawn Durable Wind Turbines  

NASA Technical Reports Server (NTRS)

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.

2014-01-01

215

Numerical Simulations of a Roof-Top Wind Turbine  

NASA Astrophysics Data System (ADS)

Unsteady numerical simulations of a high efficiency roof-top wind turbine have been performed. The wind turbine cross section design was based on geometrical optimization study of Rahai and Hefazi for increasing contributions of the lift force to the torque, resulting in significant improvements in the performance of a vertical axis wind turbine. The wind turbine was 30 cm in diameter and 75 cm length, with 45 cm diameter end-plates, placed in the spanwise direction above a 26 degree slanted roof at 20 percent from the roof's highest elevation and one turbine diameter away from the roof surface. The approaching wind velocity was 30 m/sec and the wind turbine RPM was 233. Results indicate nearly 20 percent improvements in the power output, when compared with the corresponding results for a free standing wind turbine. However, the wind turbine operation imposes oscillatory stress on the roof, which could results in structural vibration and damage and noise generation.

Moayedian, Shahab; Rahai, Hamid

2010-11-01

216

Effects of Wind Turbine Farms on Air Defence Radars.  

National Technical Information Service (NTIS)

The UK Government supports the introduction of wind turbine farms as part of its alternative energy strategy but existing Ministry of Defense (MoD) Guidelines restrict planning consent for wind turbine farms within 60% of maximum instrumented range (inter...

2005-01-01

217

Power Performance Test Report for the SWIFT Wind Turbine.  

National Technical Information Service (NTIS)

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...

I. Mendoza J. Hur

2012-01-01

218

Magnus wind turbines as an alternative to the blade ones  

NASA Astrophysics Data System (ADS)

Experimental and calculated data on a wind turbine equipped with rotating cylinders instead of traditional blades are reported. Optimal parameters and the corresponding operational characteristics of the windwheel are given in comparison with those of the blade wind turbines.

Bychkov, N. M.; Dovgal, A. V.; Kozlov, V. V.

2007-07-01

219

Safety, reliability and condition monitoring of wind turbines. Proceedings.  

National Technical Information Service (NTIS)

During recent years the number of wind turbines installed in the UK has grown rapidly. Operators of wind turbines require a reliable performance with minimum outage times in order to ensure commercial viability. Safety and reliability are clearly of param...

G. M. Smith B. R. Clayton

1992-01-01

220

Methods of making wind turbine rotor blades  

DOEpatents

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.

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

221

The NASA Lewis large wind turbine program  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

222

Wind Speed Estimation Based Sensorless Output Maximization Control for a Wind Turbine Driving a DFIG  

Microsoft Academic Search

This paper proposes a wind speed estimation based sensorless maximum wind power tracking control for variable-speed wind turbine generators (WTGs). A specific design of the proposed control algorithm for a wind turbine equipped with a doubly fed induction generator (DFIG) is presented. The aerodynamic characteristics of the wind turbine are approximated by a Gaussian radial basis function network based nonlinear

Wei Qiao; Wei Zhou; JosÉ M. Aller; Ronald G. Harley

2008-01-01

223

Advanced wind turbine design studies: Advanced conceptual study  

Microsoft Academic Search

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

P. Hughes; R. Sherwin

1994-01-01

224

TurbSim: Reliability-based wind turbine simulator  

Microsoft Academic Search

Wind turbine farms are an effective generator of electricity in windy parts of the world, with prices progressing to levels competitive with other sources. Choosing the correct turbine for a given installation requires significant engineering and the current trend leads towards groups of large horizontal axis turbines. Unfortunately, large wind turbines have to contend with large forces and other sources

Joseph T. Foley; Timothy G. Gutowski

2008-01-01

225

Battery Voltage Stability Effects on Small Wind Turbine Energy Capture.  

National Technical Information Service (NTIS)

Previous papers on small wind turbines have shown that the ratio of battery capacity to wind capacity (known as battery-wind capacity ratio) for small wind systems with battery storage has an important effect on wind turbine energy output. Data analysis f...

D. Corbus C. Newcomb E. I. Baring-Gould S. Friedly

2002-01-01

226

A simulation model for wind turbine blade fatigue loads  

Microsoft Academic Search

The paper describes a horizontal axis wind turbine time domain simulation and fatigue estimation program written using the DelphiTM language. The program models the flapwise motion of a single rotor blade to determine the blade-root fatigue damage of a medium size wind turbine. The effects of turbulence intensity, mean wind speed, wind shear, vertical wind component, dynamic stall, stall hysteresis,

M. Noda; R. G. J. Flay

1999-01-01

227

Structural dynamic analysis of wind turbine systems  

NASA Astrophysics Data System (ADS)

The paper presents an overview of the dynamic analysis of horizontal axis wind turbines. The major emphasis of the paper is the review of current analysis methods and the comparison of results with experimental data. The current capabilities for predicting turbine system natural frequencies are discussed and the design implications of frequency placement are reviewed. The prediction of cyclic loads, using the dynamic analysis computer codes, is examined and comparisons are made between the code predictions and field test data. Finally, the dynamic analysis needs for advanced turbine systems are considered.

Thresher, R. W.

1982-05-01

228

WIND TURBINE DRIVETRAIN TEST FACILITY DATA ACQUISITION SYSTEM  

Microsoft Academic Search

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,

2012-01-01

229

Wind shear climatology for large wind turbine generators  

SciTech Connect

Climatological wind shear analyses relevant to the design and operation of multimegawatt wind turbines are provided. Insight is provided for relating the wind experienced by a rotating blade in a shear flow to the analysis results. A simple analysis of the wind experienced by a rotating blade for three types of wind shear profiles under steady-state conditions is presented in graphical form. Comparisons of the magnitude and frequency of the variations in 1) the wind sensed by a single blade element, 2) the sum, and 3) the difference of the winds sensed by opposite blade elements show strong sensitivity to profile shape. These three items represent forcing functions that can be related to 1) flatwise bending moment, 2) torque on the shaft, and 3) teeter angle. A computer model was constructed to simulate rotational sampling of 10-s sampled winds from a tall tower for three different types of large wind turbines. Time series produced by the model indicated that the forcing functions on a rotating blade vary according to the shear profile encountered during each revolution as opposed to a profile derived from average wind conditions, e.g., hourly average winds. An analysis scheme was developed to establish a climatology of wind shear profiles derived from 10-s sampled winds and hourly average winds measured over a one-year period at several levels on a tall tower. Because of the sensitivity of the forcing function variability to profile shape, the analyses performed and presented are in the form of joint frequency distributions of velocity differences of the the top-to-hub versus the hub-to-bottom portion of disks of rotation for the three turbine configurations.

Elliott, D.L.; Wendell, L.L.; Heflick, S.K.

1982-10-01

230

Aileron controls for wind turbine applications  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

231

Linearized model for wind turbines in yaw  

NASA Astrophysics Data System (ADS)

The analysis of rigid hut, three bladed horizontal axis, axisymmetric wind turbines in yaw is made using a linearized, four degree of freedom model. The linearized equations of motion of rotor and nacelle are developed using quasi-steady blade element theory and Lagrange's equations. The yaw behavior of the system is studied from coefficients of the equations of motion. Analytical results for two wind turbines are presented and studied. Sensitivity study of the terms in the yaw stiffness coefficient is made. Two FORTRAN computer programs are developed to compute the numerical values of coefficients of the equations of motion.

Chaiyapinunt, S.

232

Aeroelastic simulation of wind turbine blades  

Microsoft Academic Search

\\u000a The aim of this chapter is to compute dynamic stresses acting on wind turbine blades. These stresses are essential in predicting\\u000a fatigue of the rotor.\\u000a \\u000a \\u000a The turbine rotor is exposed to wind loading of a cyclic nature, making it vulnerable to cumulative fatigue damage.\\u000a \\u000a \\u000a The approach used in this chapter is based on the analysis of the blade movement, by

Z. L. Mahri; M. S. Rouabah; Z. Said

233

Mod-2 wind turbine field operations experience  

NASA Technical Reports Server (NTRS)

The Mod-2 wind turbine is now in a 2-year research/experimental operations phase which offers a unique opportunity to study the effects of single and multiple wind turbines interacting with each other, the power grid, and the environment. This paper addresses the field operations and research testing experienced at the Mod-2 Cluster Goodnoe Hills Research Test Site near Goldendale, WA. Field operation, both routine and nonroutine, are discussed as well as the role of the participating utility. Technical areas discussed pertain to system performance and loads. Specific research tests relating to acoustics, TV interference, and wake effects are also discussed.

Gordon, L. H.

1984-01-01

234

Dynamic stall on wind turbine blades  

SciTech Connect

Dynamic loads must be predicted accurately in order to estimate the fatigue life of wind turbines operating in turbulent environments. Dynamic stall contributes to increased dynamic loads during normal operation of all types of horizontal-axis wind turbine (HAWTs). This report illustrates how dynamic stall varies throughout the blade span of a 10 m HAWT during yawed and unyawed operating conditions. Lift, drag, and pitching moment coefficients during dynamics stall are discussed. Resulting dynamic loads are presented, and the effects of dynamic stall on yaw loads are demonstrated using a yaw loads dynamic analysis (YAWDYN). 12 refs., 22 figs., 1 tab.

Butterfield, C.P.; Simms, D.; Scott, G. (National Renewable Energy Lab., Golden, CO (United States)); Hansen, A.C. (Utah Univ., Salt Lake City, UT (United States))

1991-12-01

235

Power transformer with superconducting windings  

SciTech Connect

The authors have designed, constructed and tested a 330 kVA power transformer with superconducting windings. A niobium-titanium based superconducting wire optimized for AC applications was used in die windings. The transformer worked according to its design at rated power. The total heat input to the liquid helium bath at this power was 9.4 Watts, of which the AC losses dissipated in the windings were about one Watt per winding. The low voltage feedthroughs which had to carry 830 A[sub rms] at rated power worked adequately. The transformer revealed an apparent current limiting effect. This property can be utilized to limit currents in a network for time periods 10-50 ms. A quench protection device was designed and incorporated in the test circuit.

Hoernfeldt, S.; Albertsson, O. (ABB Corp. Research, Vaesteraas (Sweden)); Bonmann, D. (ABB Transformatoren GmbH, Mannheim (Germany)); Koenig, F. (ABB Corp. Research, Zuerich (Switzerland). Oerlikon Works)

1993-11-01

236

Assessment of fatigue life for small composite wind turbine blades  

Microsoft Academic Search

The present design and assessment of fatigue life for the small composite wind turbine blades (SCWTBs) can be certified by IEC 61400-2 “Wind Turbines - Part2: Design requirements of small wind turbines”. The paper will establish an analytical method on the fatigue life analysis of SCWTBs. Using the Microsoft Office EXCEL to calculate the maximum stress, minimum stress and stress

Jia-Hroung Wu

2010-01-01

237

Study on Lightning Protection Methods for Wind Turbine Blades  

Microsoft Academic Search

Lightning protection measures for wind turbines are becoming important as the use of wind turbines is increasing rapidly along with its capacity and height. In order to understand the manner of lightning attachment to wind turbine blades, experiments with various types of blade samples were conducted. Experimental studies revealed following issues. Regarding a non-conductive blade sample, the 50% flashover voltage

Takehiro Naka; Nilesh J. Vasa; Shigeru Yokoyama; Atsushi Wada; Akira Asakawa; Hideki Honda; Kazuhisa Tsutsumi; Shinji Arinaga

2005-01-01

238

Transient grounding characteristics of wind turbine with counterpoise  

Microsoft Academic Search

Installations of wind turbine generator systems are noteworthy examples of eco-friendly energy generation. Because larger-scale facilities and increased electrical capacity can be realized by increasing the number of turbines, wind energy can be utilized more efficiently than other clean energy sources. However, the number of lightning strikes has increased with the popularization of wind turbine generator systems because of their

Junichi Niihara; Akihiro Ametani; Kazuo Yamamoto

2012-01-01

239

Initialization of wind turbine models in power system dynamics simulations  

Microsoft Academic Search

As a result of increasing environmental concern, increasing amounts of electricity are generated from renewable sources. One way of generating electricity from renewable sources is to use wind turbines. A tendency to erect more wind turbines can be observed. As a result of this, in the near future wind turbines may start to influence the behavior of electrical power systems.

J. G. Slootweg; H. Polinder; W. L. Kling

2001-01-01

240

Flicker emission of wind turbines during continuous operation  

Microsoft Academic Search

This paper presents an analysis and the modeling of the flicker emission of wind turbines. Measurements compared with international standards are discussed. The paper concentrates on the theoretical aspects of the flicker algorithm, wind turbine characteristics and the generation of flicker during continuous operation of wind turbines

Åke Larsson

2002-01-01

241

Modeling of wind turbines for power system studies  

Microsoft Academic Search

In this paper, the modeling of wind turbines for power system studies is investigated. Complexities of various parts of a wind turbine model, such as aerodynamic conversion, drive train, and generator representation, are analyzed. The results are verified by field measurements made on a stall-regulated fixed-speed wind turbine. The modeling focuses on deriving a representation that is suitable for use

Tomas Petru; Torbjörn Thiringer

2002-01-01

242

Voltage Sag Impact on Wind Turbine Tower Vibration  

Microsoft Academic Search

In order to study the voltage sag impact on mechanical vibration of wind turbine structure a detailed model that considers all three electrical, mechanical and aerodynamic aspects of the wind turbine must be considered. A drawback of many works in the area of wind turbine simulation is that either a very simple mechanical model is used with a detailed electrical

Roohollah Fadaeinedjad; Gerry Moschopoulos; Mehrdad Moallem

2007-01-01

243

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

Microsoft Academic Search

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

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

2012-01-01

244

Control system of a MW-class wind turbine  

Microsoft Academic Search

This dissertation is on control system for MW-class wind turbine. The basic control structure is on the performance of wind turbine and is a control system tracked power curve. To track the power curve, we discuss the control method for variable speed variable pitch that is used for torque control and pitch control. Furthermore, the MW-class wind turbine is a

Jeonggi Kim; Janghwan Cho; Hansoon Choi; Yoonsu Nam

2010-01-01

245

Interaction between Electrical Grid Phenomena and the Wind Turbine's Behaviour  

Microsoft Academic Search

The paper gives an overview of fundamental electrical aspects that are relevant for wind turbine designers or users. The notions 'three phase systems', 'active and reactive power', 'short-circuit power', 'ancillary services' and 'power quality' are briefly reviewed. The three most important generator types for wind turbines are reviewed. The block model approach for simulating wind turbines in power systems is

J. Soens; J. Driesen; R. Belmans

246

Tutorial of Wind Turbine Control for Supporting Grid Frequency through Active Power Control: Preprint  

Microsoft Academic Search

As wind energy becomes a larger portion of the world's energy portfolio and wind turbines become larger and more expensive, wind turbine control systems play an ever more prominent role in the design and deployment of wind turbines. The goals of traditional wind turbine control systems are maximizing energy production while protecting the wind turbine components. As more wind generation

J. Aho; A. Buckspan; J. Laks; P. Fleming; Y. Jeong; F. Dunne; M. Churchfield; L. Pao; K. Johnson

2012-01-01

247

Wind Turbine Generator System Power Quality Test Report for the Gaia Wind 11-kW Wind Turbine  

SciTech Connect

This report details the power quality test on the Gaia Wind 11-kW Wind Turbine as part of the U.S. Department of Energy's Independent Testing Project. In total five turbines are being tested as part of the project. Power quality testing is one of up to five test that may be performed on the turbines including power performance, safety and function, noise, and duration tests. The results of the testing provide manufacturers with reports that may be used for small wind turbine certification.

Curtis, A.; Gevorgian, V.

2011-07-01

248

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

SciTech Connect

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.

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

2010-05-01

249

Flow separation on wind turbines blades  

Microsoft Academic Search

In the year 2000, 15GW of wind power was installed throughout the world, producing 100PJ\\u000aof energy annually. This contributes to the total electricity demand by only 0.2%. Both the\\u000ainstalled power and the generated energy are increasing by 30% per year world-wide. If the\\u000aairflow over wind turbine blades could be controlled fully, the generation efficiency and thus\\u000athe

G. P. Corten

2001-01-01

250

Nation's tallest VAWT (Vertical Axis Wind Turbine) turning out the watts. [Vertical Axis Wind Turbine  

SciTech Connect

This article describes the development of the tallest and most powerful windmill of its kind in the U.S. Known as a Vertical Axis Wind Turbine (VAWT), the machine is meant for testing new concepts in vertical axis turbine design. As part of its overall testing program, the turbine will supply electricity to automated water pumps used in irrigation research at the Research Laboratory in Bushland, Texas. Excess power will go to the Southwestern Public Service Company for the area power system.

Miller, S.

1988-05-01

251

Root region airfoil for wind turbine  

DOEpatents

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.

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

1995-01-01

252

Structural health monitoring of wind turbine blades  

Microsoft Academic Search

As electric utility wind turbines increase in size, and correspondingly, increase in initial capital investment cost, there is an increasing need to monitor the health of the structure. Acquiring an early indication of structural or mechanical problems allows operators to better plan for maintenance, possibly operate the machine in a de-rated condition rather than taking the unit off-line, or in

Mark A. Rumsey; Joshua A. Paquette

2008-01-01

253

Fatigue of fiberglass wind turbine blade materials  

Microsoft Academic Search

Fatigue behavior for a variety of generic materials used in wind turbine blades was explored. Coupon testing was carried out under constant amplitude tensile fatigue loading to beyond 10(exp 7) cycles for most materials. Unidirectional materials performed close to expectations despite fiber misalignment. Materials with triaxial (0\\/plus or minus 45) reinforcement showed greater fatigue sensitivity than expected, but lifetime trends

J. F. Mandell; R. M. Reed; D. D. Samborsky

1992-01-01

254

Panel resonant behavior of wind turbine blades  

Microsoft Academic Search

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

Joshua A. Paquette; Daniel Todd Griffith

2010-01-01

255

Wind turbine generator with improved operating subassemblies  

Microsoft Academic Search

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

Cheney Jr

1985-01-01

256

Wind turbine speed control by automatic yawing  

Microsoft Academic Search

A yaw dynamics analysis was developed for a two-bladed horizontal axis wind turbine with passive cyclic pitch variation achieved by letting the blade pair freely oscillate about a common axis with which the blades formed a small prelag angle. This type of rotor was found capable of high yaw rates without imposing vibratory hub moments and without producing noticeable flapping

Kurt H. Hohenemser; Andrew H. P. Swift

1983-01-01

257

Full Life Wind Turbine Gearbox Lubricating Fluids  

Microsoft Academic Search

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

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

2012-01-01

258

Power converter for wind turbine application  

Microsoft Academic Search

Variable speed wind turbines are known to provide more effective power capture than their fixed-speed counterparts. To generate electrical power over a wide range of speeds, induction generators have been shown to be superior in many ways to DC generators: efficiency, maintainability, power density, etc. Unfortunately, loads are typically fixed-frequency. A power electronic converter enables efficient conversion of the variable

Herbert L. Hess; Noor A. Abdul Melek; E. Muljadi

2000-01-01

259

Self-regulating composite bearingless wind turbine  

Microsoft Academic Search

The Composite Bearingless Rotor (CBR) concept has been shown to have characteristics ideally suited for wind turbine applications. Originally developed for helicopters to reduce weight, costs, and complexity, the CBR eliminates blade bearings and hinges through the utilization of the unique structural characteristics of uniaxial composite materials. This rotor concept was further developed under an ERDA contract to provide a

M. C. Cheney; P. A. M. Spierings

1976-01-01

260

Latest wind turbine designs bolster industry confidence  

Microsoft Academic Search

This article describes a new generation of turbine designs, along with government incentives and support, that are prompting windpower projects with projected performance and economics that seem to satisfy the financiers. Wind-energy powerplants have been struggling to enter that promised land of commercially acceptable electric generation options for almost a decade. Ironically, some environmental groups, once ardent supporters of the

Makansi

1994-01-01

261

A Gust Model for Wind Turbine Design  

Microsoft Academic Search

A new method, so called constrained stochastic simulation, has been developed in order to generate extreme gust time series, to be used to calculate the extreme loading of wind turbines. A constrained simulation corresponds to the addition, in a special manner, of turbulence and a deterministic part (which resembles the auto correlation function of turbulence). The stochastic gusts produced in

Wim Bierbooms

2004-01-01

262

Optimization of wind turbine design for SWECS  

Microsoft Academic Search

Current research to optimize wind turbine designs centers on the most important parameter, the useful lifetime of the rotor assembly. A rotor design which promises to extend the lifetime of the full rotor assembly is discussed. That design improvement includes the integration of a teetered rotor hub and a delta-3 angle. This design concept was proven in helicopter and rotor

P. J. Bryant

1983-01-01

263

Wooden wind turbine blade manufacturing process  

DOEpatents

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.

Coleman, Clint (Warren, VT)

1986-01-01

264

Structural Health Monitoring of Wind Turbine Blades  

Microsoft Academic Search

As electric utility wind turbines increase in size, and correspondingly, increase in initial capital investment cost, there is an increasing need to monitor the health of the structure. Acquiring an early indication of structural or mechanical problems allows operators to better plan for maintenance, possibly operate the machine in a de-rated condition rather than taking the unit off-line, or in

Mark A. Rumsey; Joshua A. Paquette

265

Dynamic stall model for wind turbine airfoils  

Microsoft Academic Search

A model is presented for aerodynamic lift of wind turbine profiles under dynamic stall. The model combines memory delay effects under attached flow with reduced lift due to flow separation under dynamic stall conditions. The model is based on a backbone curve in the form of the static lift as a function of the angle of attack. The static lift

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

2007-01-01

266

Infrasound from Wind Turbines Could Affect Humans  

ERIC Educational Resources Information Center

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…

Salt, Alec N.; Kaltenbach, James A.

2011-01-01

267

Wind Turbine Tribology Seminar - A Recap  

Microsoft Academic Search

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

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

2012-01-01

268

SUCTION CAISSON FOUNDATIONS FOR OFFSHORE WIND TURBINES  

Microsoft Academic Search

Suction caisson foundations are being investigated for oshore wind turbine applications. The research programme includes laboratory testing, larger scale field testing and theoretical modelling. This paper concentrates on the experi- mental results obtained in combined loading tests on monopod caissons. Results obtained from monotonic and cyclic tests on caissons installed either by pushing or by suction are presented and interpreted.

Felipe A. Villalobos; Guy T. Houlsby; Byron W. Byrne

269

Actuator control of edgewise vibrations in wind turbine blades  

NASA Astrophysics Data System (ADS)

Edgewise vibrations with low aerodynamic damping are of particular concern in modern multi-megawatt wind turbines, as large amplitude cyclic oscillations may significantly shorten the life-time of wind turbine components, and even lead to structural damages or failures. In this paper, a new blade design with active controllers is proposed for controlling edgewise vibrations. The control is based on a pair of actuators/active tendons mounted inside each blade, allowing a variable control force to be applied in the edgewise direction. The control forces are appropriately manipulated according to a prescribed control law. A mathematical model of the wind turbine equipped with active controllers has been formulated using an Euler-Lagrangian approach. The model describes the dynamics of edgewise vibrations considering the aerodynamic properties of the blade, variable mass and stiffness per unit length and taking into account the effect of centrifugal stiffening, gravity and the interaction between the blades and the tower. Aerodynamic loads corresponding to a combination of steady wind including the wind shear and the effect of turbulence are computed by applying the modified Blade Element Momentum (BEM) theory. Multi-Blade Coordinate (MBC) transformation is applied to an edgewise reduced order model, leading to a linear time-invariant (LTI) representation of the dynamic model. The LTI description obtained is used for the design of the active control algorithm. Linear Quadratic (LQ) regulator designed for the MBC transformed system is compared with the control synthesis performed directly on an assumed nominal representation of the time-varying system. The LQ regulator is also compared against vibration control performance using Direct Velocity Feedback (DVF). Numerical simulations have been carried out using data from a 5-MW three-bladed Horizontal-Axis Wind Turbine (HAWT) model in order to study the effectiveness of the proposed active controlled blade design in reducing edgewise vibrations. Results show that the use of the proposed control scheme significantly improves the response of the blade and promising performances can be achieved. Furthermore, under the conditions considered in this study quantitative comparisons of the LQ-based control strategies reveal that there is a marginal improvement in the performances obtained by applying the MBC transformation on the time-varying edgewise vibration model of the wind turbine.

Staino, A.; Basu, B.; Nielsen, S. R. K.

2012-03-01

270

Development of the Risø wind turbine airfoils  

NASA Astrophysics Data System (ADS)

This paper presents the wind turbine airfoil development at Risø. The design method is described together with our target characteristics for wind turbine airfoils. The use of the CFD code Ellipsys2D for prediction of final target characteristics is described together with the VELUX wind tunnel testing setup. Three airfoil families were developed; Risø-A1, Risø-P and Risø-B1. The Risø-A1 airfoil family was developed for rotors of 600 kW and larger. Wind tunnel testing and field testing showed that this airfoil family is well suited for stall and active stall control. However, sensitivity to roughness was higher than expected. Field tests of a 600 kW active stall wind turbine showed an estimated reduction in blade fatigue loading of up to 15% at the same annual energy yield and at the same time reduced blade weight and blade solidity. The Risø-P airfoils were developed to replace the Risø-A1 airfoils for use on pitch controlled wind turbines. Improved design objectives should reduce the sensitivity to roughness, but measurements are not yet available. The Risø-B1 airfoil family was developed for variable speed operation with pitch control of large megawatt sized rotors. Wind tunnel testing verified the high maximum lift for these airfoils, and the airfoils were found to be very insensitive to leading edge roughness. Performance with vortex generators and Gurney flaps in combination was found to be attractive for the blade root part. Field testing of a 1.5 MW rotor is in progress. Copyright

Fuglsang, Peter; Bak, Christian

2004-04-01

271

Aggregation of doubly fed induction generators wind turbines under different incoming wind speeds  

Microsoft Academic Search

The increasing wind power penetration in power systems requires the development of adequate wind farms models to be included in power system simulation software in order to represent the behavior of wind farms in power systems. The modeling of wind farms with high number of wind turbines requires the development of a high order model if all the wind turbines

L. M. Fernandez; C. A. Garcia; F. Jurado; J. R. Saenz

2005-01-01

272

The UAE wind turbine performance prediction using wind tunnel airfoil data  

Microsoft Academic Search

It's vitally important for wind turbine aerodynamic performance predictions to design and optimize wind turbines. In view of the BEM method's fast speed and widespread use, this paper applies WT_Perf software of NREL to predict the performance on a NREL Phase VI upwind wind turbine. Measurements from the Phase VI of the NREL\\/NASA Ames wind tunnel test were used for

Chenkai Zhang; Jun Hu

2010-01-01

273

The effect of wind shear and pitch control delaying on wind turbine blade loading  

Microsoft Academic Search

The loading analysis model of wind turbine blade is established according to strip theory of rotor aerodynamics. For a 1.5MW wind turbine, the force distribution on blade at rated wind speed and the moments of the blade root in various work case are dealt with by this model. The Effect of pitch control delaying on the loads of wind turbine

Jie Fu; Hui-ling Zhang; Bin He; Qin-shan Fan

2011-01-01

274

Review of offshore wind turbine failures and fault prognostic methods  

Microsoft Academic Search

Wind electricity is a highly promoted energy source all around the world. The number of offshore wind farms, increases gradually because of the high capability of power generation. However, the cost of manufacturing, logistics, installation, grid control and maintenance of offshore wind turbine is high. According to the Condition Monitoring of Offshore Wind Turbine (CONMOW) report of Energy Research Centre

Bill Chun Piu Lau; Eden Wai Man Ma; Michael Pecht

2012-01-01

275

Periodic pulsations from a three-bladed wind turbine  

Microsoft Academic Search

In this paper, periodic power pulsations from a three-bladed wind turbine are analyzed. The influence of wind shear, wind speed, turbulence intensity, rotor position and tower oscillation is investigated. No clear dependence between the periodic power components and the wind shear or turbulence intensity has been verified. The investigated turbine sometimes produces large power pulsations at the tower resonance frequency.

Torbjörn Thiringer; Jan-Åke Dahlberg

2001-01-01

276

Electrical generation using a vertical-axis wind turbine  

Microsoft Academic Search

Traditionally, windmills have been of the propeller or multiblade types, both of which have their rotational axis parallel to the flow of the wind. A vertical-axis wind turbine has its rotational axis perpendicular to the flow of wind and requires no orientation to keep the rotor in the windstream. The vertical-axis wind turbine operates on the same principle as an

1982-01-01

277

Performance characteristics of aerodynamically optimum turbines for wind energy generators  

NASA Technical Reports Server (NTRS)

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.

Rohrbach, C.; Worobel, R.

1975-01-01

278

Duration Test Report for the Viryd CS8 Wind Turbine  

SciTech Connect

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.

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

2013-06-01

279

Selected wind tunnel test results for the Darrieus wind turbine  

Microsoft Academic Search

Five blade configurations of a 2-m-diam Darrieus wind turbine have been tested in the Vought Corporation 4.6- x 6.1-m (15- x 20-ft) Low-Speed Wind Tunnel. Rotor solidity, Reynolds number, and freestream velocities tested were in the following ranges: solidity, 13 to 30%; Reynolds number, 1 to 3 x 10⁵; freestream velocity, 7 to 11 m\\/s. The airfoil selection for all

B. F. Blackwell; R. E. Sheldahl

1977-01-01

280

Selected wind tunnel test results for the Darrieus wind turbine  

Microsoft Academic Search

Five blade configurations of a 2-m-diam Darrieus wind turbine have been tested in a low-speed wind tunnel. Rotor solidity, Reynolds number, and free-stream velocities tested were in the following ranges: solidity, 13-30%; Reynolds number, 100,000-300,000; free-stream velocity, 7-11 m\\/s. The airfoil selection for all configurations was NACA 0012. The parameters measured were rotor torque, rotor rotational speed, and tunnel conditions.

B. F. Blackwell; R. E. Sheldahl

1977-01-01

281

Modern control design for flexible wind turbines  

NASA Astrophysics Data System (ADS)

Control can improve energy capture and reduce dynamic loads in wind turbines. In the 1970s and 1980s wind turbines used classical control designs to regulate power and speed. The methods used, however, were not always successful. These systems often had bandwidths large enough to destabilize low-damped flexible modes leading to high dynamic load fatigue failures. Modern turbines are larger, mounted on taller towers, and are more dynamically active than their predecessors. Control systems to regulate turbine power and maintain stable closed-loop behavior in the presence of turbulent wind inflow will be critical for these designs. New advanced control approaches and paradigms must account for low-damped flexible modes in order to reduce structural dynamic loading and achieve the 20--25 year operational life required of today's machines. This thesis applies modern state-space control design methods to a two-bladed teetering hub upwind machine located at the National Wind Technology Center. The design objective is to regulate turbine speed and enhance damping in several low-damped flexible modes of the turbine. Starting with simple control algorithms based on linear models, complexity is added incrementally until the desired performance is firmly established. The controls approach is based on the Disturbance Accommodating Control (DAC) method and provides accountability for wind-speed fluctuations. First, controls are designed using the single control input rotor collective pitch to stabilize the 1st drive-train torsion as well as the tower 1st fore-aft bending modes. Generator torque is then incorporated as an additional control input. This reduces some of the demand placed on the rotor collective pitch control system and enhances 1st drive train torsion mode damping. Individual blade pitch control is then used to attenuate wind disturbances having spatial variation over the rotor and effectively reduces blade flap deflections due to wind shear. Finally, results from these modern controls are compared to results from simpler classical controls in order to assess modern controller performance. These modern controls are shown to more effectively mitigate tower fore-aft motion, drive-train shaft torsion moments, and blade root flap bending moments when compared to the classical control approaches.

Wright, Alan Duane

282

Dynamic behavior of variable speed wind turbines under stochastic wind  

Microsoft Academic Search

It is recognized that the most important advantage of the variable speed wind turbines (VS WTs) over the conventional constant speed (CS) machines are the improved dynamic characteristics, resulting in the reduction of the drive train mechanical stresses and output power fluctuations. In this paper alternative configurations of the electrical part of a VS WT are considered, using a squirrel

S. A. Papathanassiou; M. P. Papadopoulos

1999-01-01

283

NREL Small Wind Turbine Test Project: Mariah Power's Windspire Wind Turbine Test Chronology.  

National Technical Information Service (NTIS)

To help industry offer consumers more small wind turbine systems that are certified for safety and performance, the National Renewable Energy Laboratory (NREL) and the U.S. Department of Energy (DOE) launched a Small Wind Independent Testing project in 20...

A. Huskey T. Forsyth

2009-01-01

284

A simple method of estimating wind turbine blade fatigue at potential wind turbine sites  

Microsoft Academic Search

This paper presents a technique of estimating blade fatigue damage at potential wind turbine sites. The cornerstone of this technique is a simple model for the blade's root flap bending moment. The model requires as input a simple set of wind measurements which may be obtained as part of a routine site characterization study. By using the model to simulate

J. C. Barnard; L. L. Wendell

1995-01-01

285

A simple method of estimating wind turbine blade fatigue at potential wind turbine sites  

Microsoft Academic Search

This paper presents a technique of estimating blade fatigue damage at potential wind turbine sites. The cornerstone of this technique is a simple model for the blade`s root flap bending moment. The model requires as input a simple set of wind measurements that may be obtained as part of a routine site characterization study. By using the model to simulate

J. C. Barnard; L. L. Wendell

1997-01-01

286

Lightning discharges produced by wind turbines  

NASA Astrophysics Data System (ADS)

observations with a 3-D Lightning Mapping Array and high-speed video are presented and discussed. The first set of observations shows that under certain thunderstorm conditions, wind turbine blades can produce electric discharges at regular intervals of ~3 s in relation to its rotation, over periods of time that range from a few minutes up to hours. This periodic effect has not been observed in static towers indicating that the effect of rotation is playing a critical role. The repeated discharges can occur tens of kilometers away from electrically active thunderstorm areas and may or may not precede a fully developed upward lightning discharge from the turbine. Similar to rockets used for triggering lightning, the fast movement of the blade tip plays an important role on the initiation of the discharge. The movement of the rotor blades allows the tip to "runaway" from the generated corona charge. The second observation is an uncommon upward/downward flash triggered by a wind turbine. In that flash, a negative upward leader was initiated from a wind turbine without preceding lightning activity. The flash produced a negative cloud-to-ground stroke several kilometers from the initiation point. The third observation corresponds to a high-speed video record showing simultaneous upward positive leaders from a group of wind turbines triggered by a preceding intracloud flash. The fact that multiple leaders develop simultaneously indicates a poor shielding effect among them. All these observations provide some special features on the initiation of lightning by nonstatic and complex tall structures.

Montanyà, Joan; Velde, Oscar; Williams, Earle R.

2014-02-01

287

Wind Forces and Peak Wind Pressure Distributions on Wind Turbine Nacelle  

Microsoft Academic Search

ABSRRACT In this paper, wind forces acting on a nacelle of wind turbine were measured in the wind tunnel experiments. In order to investigate the validity of application of surface mounted structure data on nacelle enclosure, two kinds of experiments, i.e. model set up on wind tunnel floor and the one apart from floor are carried out. Based on the

Hiroshi Nod; Kenji Shimada; Takeshi Ishihara

288

SUSTAINABLE CONCRETE FOR WIND TURBINE FOUNDATIONS.  

SciTech Connect

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.

BERNDT,M.L.

2004-06-01

289

Yaw dynamics of horizontal axis wind turbines  

NASA Astrophysics Data System (ADS)

Numerous problems associated with yaw exist on free-yaw and yaw-driven wind turbines. Yaw-driven machines experience failures in the yaw drive mechanism due to excessive loads, while free-yaw machines experience high yaw rates and yaw misalignment problems. This report describes validation of a model for prediction of wind turbine yaw behavior. The model accounts for the coupled yaw and blade flapping motion of wind machines. The results from the model are compared to results from other analysis methods and to test data. Wind tunnel tests of a rigid-hub, two-bladed rotor, as well as full scale field test data from a rigid-hub, three-bladed turbine are used as the comparison cases in this report. The model predictions show good qualitative agreement with test data, but the magnitudes of predicted yaw moments are in error for some comparison cases. Future work will involve a more in-depth comparison of model results to comprehensive machine test data. Refinements will be made to the analytical model in order to improve correlations between theory and experiment.

Hansen, A.; Xudong, C.

1989-03-01

290

Control of large wind turbine generators connected to utility networks  

NASA Technical Reports Server (NTRS)

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.

Hinrichsen, E. N.

1983-01-01

291

Site matching of wind turbine generators: a case study  

Microsoft Academic Search

Site matching of wind turbine generators is investigated based on the appropriate selection of statistical models and means of wind speed data. The wind speed means are computed using arithmetic mean, root mean square and cubic mean cuberoot. Wind speed frequency distributions are modelled using Weibull and Rayleigh probability density functions. Wind speed data of an existing wind power station,

S. H. Jangamshetti; V. G. Rau

1999-01-01

292

Wind and turbine characteristics needed for integration of wind turbine arrays into a utility system  

NASA Astrophysics Data System (ADS)

Wind data and wind turbine generator (WTG) performance characteristics are often available in a form inconvenient for use by utility planners and engineers. The steps used by utility planners are summarized and the type of wind and WTG data needed for integration of WTG arrays suggested. These included long term yearly velocity averages for preliminary site feasibility, hourly velocities on a 'wind season' basis for more detailed economic analysis and for reliability studies, worst-case velocity profiles for gusts, and various minute-to-hourly velocity profiles for estimating the effect of longer-term wind fluctuations on utility operations. wind turbine data needed includes electrical properties of the generator, startup and shutdown characteristics, protection characteristics, pitch control response and control strategy, and electro-mechanical model for stability analysis.

Park, G. L.

293

The EPRI\\/DOE Utility Wind Turbine Performance Verification Program  

Microsoft Academic Search

In 1992, the Electric Power Research Institute (EPRI) and the US Department of Energy (DOE) initiated the Utility Wind Turbine Performance Verification Program (TVP). This paper provides an overview of the TVP, its purpose and goals, and the participating utility projects. Improved technology has significantly reduced the cost of energy from wind turbines since the early 1980s. In 1992, turbines

S. Calvert; P. Goldman; E. DeMeo; C. McGowin; B. Smith; K. Tromly

1997-01-01

294

The Design of closed loop controllers for wind turbines  

Microsoft Academic Search

This article reviews the design of algorithms for wind turbine pitch control and also for generator torque control in the case of variable speed turbines. Some recent and possible future developments are discussed. Although pitch control is used primarily to limit power in high winds, it also has a significant effect on various loads. Particularly as turbines become larger, there

E. A. Bossanyi

2000-01-01

295

Gearing ratios of a magnetic gear for wind turbines  

Microsoft Academic Search

The wind turbine industry is growing at an incredible rate as numerous governments demand an increase in renewable energy generation capacity. The great multitude of turbines on windfarms throughout the world range from ones which are controlled mechanically with gears to ones which are controlled with power electronics and no gears. A drivetrain for a wind turbine which eliminates the

Nicolas W. Frank; Hamid A. Toliyat

2009-01-01

296

Wind shear for large wind turbine generators at selected tall tower sites  

SciTech Connect

The objective of the study described in this report is to examine the nature of wind shear profiles and their variability over the height of large horizontal-axis wind turbines and to provide information on wind shear relevant to the design and opertion of large wind turbines. Wind turbine fatigue life and power quality are related through the forcing functions on the blade to the shapes of the wind shear profiles and their fluctuations over the disk of rotation.

Elliott, D.L.

1984-04-01

297

Investigation on wind power potential on Hong Kong islands—an analysis of wind power and wind turbine characteristics  

Microsoft Academic Search

This paper discusses the potential for electricity generation on Hong Kong islands through an analysis of the local weather data and typical wind turbine characteristics. An optimum wind speed, uop, is proposed to choose an optimal type of wind turbine for different weather conditions. A simulation model has been established to describe the characteristics of a particular wind turbine. A

Lin Lu; Hongxing Yang; John Burnett

2002-01-01

298

Braking System for Wind Turbines  

NASA Technical Reports Server (NTRS)

Operating turbine stopped smoothly by fail-safe mechanism. Windturbine braking systems improved by system consisting of two large steel-alloy disks mounted on high-speed shaft of gear box, and brakepad assembly mounted on bracket fastened to top of gear box. Lever arms (with brake pads) actuated by spring-powered, pneumatic cylinders connected to these arms. Springs give specific spring-loading constant and exert predetermined load onto brake pads through lever arms. Pneumatic cylinders actuated positively to compress springs and disengage brake pads from disks. During power failure, brakes automatically lock onto disks, producing highly reliable, fail-safe stops. System doubles as stopping brake and "parking" brake.

Krysiak, J. E.; Webb, F. E.

1987-01-01

299

Flicker Contribution of a Wind Power Plant with Single and Multiple Turbine Representations  

Microsoft Academic Search

In order to study the impact of a wind power plant on network power quality all electrical, mechanical and aerodynamic aspects of wind turbines must be studied. Moreover, the contribution of every wind turbine on the wind power plant should be considered. Representing a large wind power plant by a single wind turbine (WT) or a few wind turbines results

Roohollah Fadaeinedjad; Mehrdad Moallem; G. Moschopoulos; S. Bassan

2007-01-01

300

Post Stall Airfoil Data for Wind Turbines: Wind Tunnel Test Results.  

National Technical Information Service (NTIS)

Wind turbine blades operate over a wide angle of attack range. Unlike aircraft, a wind turbine's angle of attack range extends deep into stall where the three dimensional performance characteristics of airfoils are not generally known. Peak power predicti...

C. Ostowari D. Naik

1984-01-01

301

Probabilistic reliability criterion for expansion planning of grids including wind turbine generators  

Microsoft Academic Search

This paper describes an alternative method, derived from a simulation model, for expansion planning for grids considering wind turbine generators in a composite power system. The proposed model includes capacity limitations and uncertainties of the generators and transmission lines. It proposes to handle the uncertainties of system elements (generators, lines, transformers and wind resources of WTG, etc.) by a Composite

Kyeonghee Cho; Taegon Oh; Jaeseok Choi; A. A. El-Keib; Mohammad Shahidehpour

2011-01-01

302

Feedback-feedforward individual pitch control for wind turbine load reduction  

Microsoft Academic Search

SUMMARY This paper focuses on the problem of wind turbine fatigue load reduction by means of individual pitch control (IPC). The control approach has a two-degree-of-freedom structure, consisting of an optimal multivariable LQG controller and a feedforward disturbance rejection controller based on estimated wind speed signals. To make the control design problem time invariant, all signals are transformed to the

K. Selvam; S. Kanev; J. W. van Wingerden; T. van Engelen; M. Verhaegen

2009-01-01

303

Survey of modelling methods for wind turbine wakes and wind farms  

Microsoft Academic Search

This article provides an overview and analysis of different wake-modelling methods which may be used as prediction and design tools for both wind turbines and wind farms. We also survey the available data concerning the measurement of wind magnitudes in both single wakes and wind farms, and of loading effects on wind turbines under single- and multiple-wake conditions. The relative

A. Crespo; J. Hernández; S. Frandsen

1999-01-01

304

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

SciTech Connect

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.

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

2010-09-01

305

Composite Materials for Wind Power Turbine Blades  

NASA Astrophysics Data System (ADS)

Renewable energy resources, of which wind energy is prominent, are part of the solution to the global energy problem. Wind turbine and the rotorblade concepts are reviewed, and loadings by wind and gravity as important factors for the fatigue performance of the materials are considered. Wood and composites are discussed as candidates for rotorblades. The fibers and matrices for composites are described, and their high stiffness, low density, and good fatigue performance are emphasized. Manufacturing technologies for composites are presented and evaluated with respect to advantages, problems, and industrial potential. The important technologies of today are prepreg (pre-impregnated) technology and resin infusion technology. The mechanical properties of fiber composite materials are discussed, with a focus on fatigue performance. Damage and materials degradation during fatigue are described. Testing procedures for documentation of properties are reviewed, and fatigue loading histories are discussed, together with methods for data handling and statistical analysis of (large) amounts of test data. Future challenges for materials in the field of wind turbines are presented, with a focus on thermoplastic composites, new structural materials concepts, new structural design aspects, structural health monitoring, and the coming trends and markets for wind energy.

Brøndsted, Povl; Lilholt, Hans; Lystrup, Aage

2005-08-01

306

Effects of precipitation on wind turbine performance  

NASA Astrophysics Data System (ADS)

This report examines the effects of precipitation on the performance of a wind turbine, with an airfoil section similar to that of the MOD-O (23000 series), at an operating wind farm. Earlier NASA research noted a performance degradation of up to 24 percent for the MOD-OA when precipitation occurred. The objective of this study was to collect sufficient data at a wind farm where rainfall occurs frequently so that the effect of precipitation could be discriminated from the effects of the turbulence that may be associated with rain. The rainfall rates were considerably lower than the rates of rainfall considered in the previous NASA study. The rainfall rates experienced at the wind farm are generally below 8mm/h and would usually fall under the light rain classification of the previous NASA study. For light rain conditions, the NASA report showed as high as an 18 percent decrease in machine performance. The study described here did not show a decrease in performance from light rain; rather an increase of approximately 3 percent was indicated. The 3 percent increase may be attributable to a reduction of blade roughness, rain effects on the anemometer, or a combination of the two. The general conclusion is drawn for this study: for the ESI-54 wind turbine studied, for rainfall rates generally less than 8mm/h, the rain has a beneficial effect on performance by slightly improving the aerodynamic properties (maintaining clean blades).

Walker, S. N.; Wade, J. E.

1988-03-01

307

The Federal Advanced Wind Turbine Program  

SciTech Connect

The development of technologically advanced, higher efficiency wind turbines has been identified as a high priority activity by the US wind industry. The Department of Energy's Wind Energy Program has begun a multi-year development program aimed at assisting the wind industry with the design, development, and testing of advanced wind turbine systems that can compete with conventional electric generation for $0.05/kWh at 13 mph sites by the mid-1990s and with fossil-fuel-based generators for $0.04/kWh at 13 mph sites by the year 2000. The development plan consists of four phases: (1) Conceptual Design Studies; (2) Near-Term Product Development; (3) Next Generation Technology Integration and Design, and (4) Next- Generation Technology Development and Testing. The Conceptual Design Studies were begun in late 1990, and are scheduled for completion in the Spring of 1992. Preliminary results from these analyses are very promising and indicate that the goals stated above are technically feasible. This paper includes a brief summary of the Conceptual Design Studies and presents initial plans for the follow-on activities. 3 refs., 4 figs.

Hock, S M; Thresher, R W [National Renewable Energy Lab., Golden, CO (United States); Goldman, P R [USDOE, Washington, DC (United States)

1991-12-01

308

The Federal Advanced Wind Turbine Program  

SciTech Connect

The development of technologically advanced, higher efficiency wind turbines has been identified as a high priority activity by the US wind industry. The Department of Energy`s Wind Energy Program has begun a multi-year development program aimed at assisting the wind industry with the design, development, and testing of advanced wind turbine systems that can compete with conventional electric generation for $0.05/kWh at 13 mph sites by the mid-1990s and with fossil-fuel-based generators for $0.04/kWh at 13 mph sites by the year 2000. The development plan consists of four phases: (1) Conceptual Design Studies; (2) Near-Term Product Development; (3) Next Generation Technology Integration and Design, and (4) Next- Generation Technology Development and Testing. The Conceptual Design Studies were begun in late 1990, and are scheduled for completion in the Spring of 1992. Preliminary results from these analyses are very promising and indicate that the goals stated above are technically feasible. This paper includes a brief summary of the Conceptual Design Studies and presents initial plans for the follow-on activities. 3 refs., 4 figs.

Hock, S.M.; Thresher, R.W. [National Renewable Energy Lab., Golden, CO (United States); Goldman, P.R. [USDOE, Washington, DC (United States)

1991-12-01

309

Root region airfoil for wind turbine  

DOEpatents

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.

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

1995-05-23

310

Latest wind turbine designs bolster industry confidence  

SciTech Connect

This article describes a new generation of turbine designs, along with government incentives and support, that are prompting windpower projects with projected performance and economics that seem to satisfy the financiers. Wind-energy powerplants have been struggling to enter that promised land of commercially acceptable electric generation options for almost a decade. Ironically, some environmental groups, once ardent supporters of the technology, are now expressing reservations.

Makansi, J.

1994-02-01

311

Case Study #8: Wind Turbine Control Design  

Microsoft Academic Search

\\u000a In Chap. 13, HSSPFC is used to develop a new nonlinear\\/adaptive power flow control strategy for below-rated power control\\u000a of variable speed wind turbines. Fundamentally, the new controller is designed to optimize both stability and performance\\u000a criteria. Numerical results demonstrate that the nonlinear\\/adaptive power flow control increases efficiency, extracting more\\u000a power when compared to a conventional control strategy. In addition, the

Rush Robinett; David Wilson

312

Flow separation on wind turbines blades  

NASA Astrophysics Data System (ADS)

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

Corten, G. P.

2001-01-01

313

International collaborative research in wind turbine rotor aerodynamics.  

National Technical Information Service (NTIS)

Five organizations from four countries are collaborating to conduct detailed wind turbine aerodynamic test programs. Fullscale atmospheric testing will be conducted on turbines configured to measure aerodynamic forces on rotating airfoils. The purpose of ...

D. A. Simms C. P. Butterfield

1993-01-01

314

On the Modelling of a Floating Offshore Wind Turbine  

NASA Astrophysics Data System (ADS)

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.

Henderson, Andrew R.; Patel, Minoo H.

2003-01-01

315

Linearized model for wind turbines in yaw  

SciTech Connect

The analysis of rigid hub, three-bladed horizontal-axis, axisymmetric wind turbines in yaw is made using a linearized, four-degree-of-freedom model. The linearized equations of motion of rotor and nacelle are developed using quasi-steady blade element theory and Lagrange's equations. The yaw behavior of the system is studied from coefficients of the equations of motion. Analytical results for two wind turbines are presented and studied. The study shows that yaw tracking error is primarily caused by tower shadow. The contribution of the nacelle to the yaw stability is proved to be a destabilizing one. The yaw stability of a wind turbine in a reverse position is investigated and used for verification of the analysis. The characteristics of yaw static stability are determined primarily by the characteristics of the in-plane force coefficient and the location of the yaw axis relative to the rotor plane. A sensitivity study of the terms in the yaw stiffness coefficient is made. The yaw static stability is strongly affected by a change in the coning angle. Two Fortran computer programs are developed to compute the numerical values of coefficients of the equations of motion. Program listings and sample outputs are included.

Chaiyapinunt, S.

1984-01-01

316

Yaw dynamics of horizontal axis wind turbines  

NASA Astrophysics Data System (ADS)

Numerous problems associated with yaw exists on free-yaw and yaw-driven wind turbines. Yaw-driven machines experience failures in the yaw drive due to excessive loads, while free-yaw machines experience high yaw rates and frequent misalignment problems. This report describes a theoretical investigation of the yaw behavior of wind turbines, which was carried out by the University of Utah. The basic approach to this analysis was to develop a series of analytical and computer models such that each successive model added complexity and increased accuracy. These models are described and compared to results from other models and also to test data. Comments are made on the models' ability to predict yaw moments and response. Also, useful insight is presented regarding the free-yaw behavior of wind turbines as observed using these models. The most complex of these models is used to predict the coupled free-yaw and flap motions of a rotor. This model, YawDyn, is operational; however, experience with it is limited. Future plans, for further enhancing and validating this model, are also discussed.

Xudong, C.; Hansen, A.; Siedschlag, N.

1988-02-01

317

Wind turbine blade tip comparison using CFD  

NASA Astrophysics Data System (ADS)

The effect of wind turbine blade tip geometry is numerically analysed using Computational Fluid Dynamics (CFD). Three different rotating blade tips are compared for attached flow conditions and the flow physics around the geometries are analysed. To this end, the pressure coefficient (Cp) is defined based on the stagnation pressure rather than on the inflow dynamic pressure. The tip geometry locally modifies the angles of attack (AOA) and the inflow dynamic pressure at each of the studied sections. However not all 3D effects could be reduced to a change of these two variables. An increase in loadings (particularly the normal force) towards the tip seem to be associated to a spanwise flow component present for the swept-back analysed tip. Integrated loads are ranked to asses wind turbine tip overall performance. It results from the comparison that a better tip shape that produced better torque to thrust ratios in both forces and moments is a geometry that has the end tip at the pitch axis. The work here presented shows that CFD may prove to be useful to complement 2D based methods on the design of new wind turbine blade tips.

Ferrer, E.; Munduate, X.

2007-07-01

318

Simulation Model of Wind Turbine 3p Torque Oscillations due to Wind Shear and Tower Shadow  

Microsoft Academic Search

To determine control structures and possible power quality issues, the dynamic torque generated by the blades of a wind turbine must be represented. This paper presents an analytical formulation of the generated aerodynamic torque of a three bladed wind turbine including effects of wind shear and tower shadow. The comprehensive model includes turbine specific parameters such as radius, height, and

Dale S. L. Dolan; P. W. Lehn

2006-01-01

319

Probabilistic identification of turbines facing high and low wind speeds in a wind farm  

Microsoft Academic Search

Due to growing number of wind turbines (WT) within a wind farm (WF) scheduling of maintenance of turbines within the WF becomes challenging issue. Also, in instances when wind energy curtailments are required it can be difficult to decide which turbines should be shut down first. In this paper, a probabilistic methodology is presented to identify WT in the WF

M. Ali; J. V. Milanovic?; I.-S. Ilie; G. Chicco

2010-01-01

320

Pitch control of wind turbine blades in noisy and unstable wind conditions  

Microsoft Academic Search

In this paper, a new approach for control of the pitch angle of the wind turbine is represented in an unstable and noisy circumstance. Moreover, it is demonstrated that output power of the wind turbine can be efficiently controlled by the proposed control system. This method enhances (amends) the stability of the wind turbine. Besides, it improves the regulation of

Mohsen Faridi; Roghaiyeh Ansari; Seyed Ali Mousavi; Mahsa Dodman

2010-01-01

321

International collaborative research in wind turbine rotor aerodynamics  

NASA Astrophysics Data System (ADS)

Five organizations from four countries are collaborating to conduct detailed wind turbine aerodynamic test programs. Fullscale atmospheric testing will be conducted on turbines configured to measure aerodynamic forces on rotating airfoils. The purpose of these test programs is to come to a better understanding of the steady and unsteady aerodynamic behavior of wind turbine rotors, and provide information needed to build accurate aerodynamic models for design codes. Stall, dynamic inflow, yaw conditions, and tower effects all contribute to unknown aerodynamic responses. These unknown responses make it extremely difficult to produce cost-effective wind turbine designs. Turbines behave unexpectedly, experiencing power surges and higher fatigue loads than predicted. In order to evolve state-of-the-art wind turbine designs, these aerodynamic effects must be quantified and understood. This paper describes a coordinated international research effort that is underway to accelerate this key research area, and help develop a more thorough understanding of wind turbine aerodynamics.

Simms, D. A.; Butterfield, C. P.

1993-12-01

322

Innovative design approaches for large wind turbine blades  

Microsoft Academic Search

A preliminary design study of an advanced 50 m blade for utility wind turbines is presented and discussed. The effort was part of the Department of Energy WindPACT Blade System Design Study with the goal to investigate and evaluate design and manufacturing issues for wind turbine blades in the 1-10 MW size range. Two different blade designs are considered and

K. J. Jackson; M. D. Zuteck; C. P. van Dam; K. J. Standish; D. Berry

2005-01-01

323

Response analysis of spar platform with wind turbine  

Microsoft Academic Search

Floating wind turbine platforms are the most economical means for deploying offshore wind turbines in deep waters. The merit of spar platform is the large range of topside payloads, favourable motions compared with other floating structures and minimum hull\\/deck interface. The main objective of this paper is to present the response analysis of the spar platform supporting a 5MW wind

Seebai T; Sundaravadivelu R

2012-01-01

324

Active yaw control of MW class wind turbine  

Microsoft Academic Search

While the yaw system of the wind turbine operates depending on the wind direction, it makes us acquire the maximum energy and its own mechanical load decreased. Hence, the optimal design of yaw system is extremely important in the design process of the wind turbine. In this study, yaw system is introduced and its efficiency is analyzed by the result

Han-Soon Choi; Jeong-Gi Kim; Jang-Hwan Cho; Yoon-su Nam

2010-01-01

325

Review of failures and condition monitoring in wind turbine generators  

Microsoft Academic Search

Increasing wind power generation quantity in power systems needs obviously reliable operation. Therefore, accurate condition monitoring and fault diagnosis are almost mandatory. This paper aims to report recent works on condition monitoring and fault diagnosis for wind turbine generators. Wind turbines are subjected to different sort of failures, thus before stating condition monitoring and fault diagnosis methods it is necessary

Z. Daneshi-Far; G. A. Capolino; H. Henao

2010-01-01

326

Multi-speed electrical generator application to wind turbines  

Microsoft Academic Search

A cost-effective method to achieve increased energy conversion from wind turbine generators is presented. Most large wind turbines designed to supply electricity to a power have been optimized at a single rotor speed to maintain synchronism with the grid. Suboptimal performance results from spatial and temporal variation in actual wind speeds. Use of mechanical or electrical devices to allow variable

T. S. Andersen; H. S. Kirschbaum

1980-01-01

327

Using neural networks to estimate wind turbine power generation  

Microsoft Academic Search

This paper uses data collected at Central and South West Services Fort Davis wind farm (USA) to develop a neural network based prediction of power produced by each turbine. The power generated by electric wind turbines changes rapidly because of the continuous fluctuation of wind speed and direction. It is important for the power industry to have the capability to

Shuhui Li; Donald C. Wunsch; Edgar A. O'Hair; Michael G. Giesselmann

2001-01-01

328

Power curve control in micro wind turbine design  

Microsoft Academic Search

In this work, a micro wind turbine will be designed and built for a series of wind tunnel tests (rotor dynamics and Wind Turbine (WT) start-up velocity). Its design stems from an original numerical code, developed by the authors, based on the Blade Element Momentum (BEM) Theory.From classic design criteria, having evaluated all the geometric characteristics, an innovative methodology will

R. Lanzafame; M. Messina

2010-01-01

329

Wind turbine design codes: A comparison of the structural response  

Microsoft Academic Search

The National Wind Technology Center (NWTC) of the National Renewable Energy Laboratory is continuing a comparison of several computer codes used in the design and analysis of wind turbines. The second part of this comparison determined how well the programs predict the structural response of wind turbines. In this paper, the authors compare the structural response for four programs: ADAMS,

M. L. Jr. Buhl; A. D. Wright; K. G. Pierce

2000-01-01

330

Demonstration project: wind turbines for municipal water pumping  

Microsoft Academic Search

In 1979, personnel from Alternative Energy Institute (AEI) studied the feasibility of using wind power in the operation of the municipal water system for the City of Canyon, Texas (1). Predicted energy outputs from six different wind turbines were calculated from power curves and long term National Weather Service (NWS) data. The conclusions were that the cheaper wind turbines should

1982-01-01

331

Depolarization effect in signals scattered by wind turbines  

Microsoft Academic Search

Introduction: Th e increase in the number of wind farms as well as their larger sizes lead to an increase in the possibility of interference with nearby radiocommunication systems. As possible disturbances scattering as well as diffraction from the wind turbine structure are considered. The wind turbines that are being installed nowadays are composed of towers with a height of

I. Etayo; A. Satrustegui; M. Yabar; F. Falcone

2011-01-01

332

Support for spinning reserve from DFIG based wind turbines  

Microsoft Academic Search

With the increased penetration of wind power, wind turbines are now expected to provide ancillary services presently performed by large synchronous generators. Among the ancillary services, frequency duties are vital and a number of papers are available in the literature to demonstrate the possibility of using DFIG based wind turbine for inertia, primary and secondary frequency support. This paper describes

G. Ramtharan; J. B. Ekanayake; N. Jenkins

2007-01-01

333

Electric power from vertical-axis wind turbines  

Microsoft Academic Search

Significant advancements have occurred in vertical axis wind turbine (VAWT) technology for electrical power generation over the last decade; in particular, well-proven aerodynamic and structural analysis codes have been developed for Darrieus-principle wind turbines. Machines of this type have been built by at least three companies, and about 550 units of various designs are currently in service in California wind

K. J. Touryan; J. H. Strickland; D. E. Berg

1987-01-01

334

Short circuit signatures from different wind turbine generator types  

Microsoft Academic Search

Modern wind power plants are required and designed to ride through faults in the network, subjected to the fault clearance and following grid code demands. Beside voltage support during faults, the wind turbine fault current contribution is important to establish the correct settings for the relay of the protections. The following wind turbine generator during faults have been studied: (i)

Jorge Martinez; Philip C. Kjar; Pedro Rodriguez; Remus Teodorescu

2011-01-01

335

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

Microsoft Academic Search

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

P. Hughes; R. Sherwin

1994-01-01

336

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

SciTech Connect

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.

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

337

Remote monitoring and nondestructive evaluation of wind turbine towers  

NASA Astrophysics Data System (ADS)

Wind turbine towers are in need of condition monitoring so as to lower the cost of unexpected maintenance. Wind loading from turbulence and gusts can cause damage in horizontal axis wind turbines even the supporting towers. Monitoring of wind turbines in service using embedded data sensor arrays usually is not targeted at the turbine-tower interaction from the perspective of structural dynamics. In this study the remote monitoring of the tower supporting a horizontal-axis wind turbine was attempted using a microwave interferometer. The dominant frequency of one tower was found to be decreased by more than 20% in 16 months. Numerical modeling using spectral finite elements is in progress and should provide further information regarding frequency shift due to stiffness variation and added mass. Expected outcome will contribute to remote monitoring procedures and nondestructive evaluation techniques for local wind turbine structures during operation.

Chiang, Chih-Hung; Yu, Chih-Peng; Hsu, Keng-Tsang; Cheng, Chia-Chi; Ke, Ying-Tzu; Shih, Yi-Ru

2014-03-01

338

Dynamic modeling of doubly fed induction generator wind turbines  

Microsoft Academic Search

It is now recognized that many large wind farms will employ doubly fed induction generator (DFIG) variable speed wind turbines. A number of such wind farms are already in operation and more are planned or under construction. With the rising penetration of wind power into electricity networks, increasingly comprehensive studies are required to identify the interaction between the wind farm(s)

Janaka B. Ekanayake; Lee Holdsworth; XueGuang Wu; Nicholas Jenkins

2003-01-01

339

Superconductivity for Large Scale Wind Turbines  

SciTech Connect

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.

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

340

Wind turbine inspection tests at UCSD  

NASA Astrophysics Data System (ADS)

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.

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

2012-03-01

341

Analysis of the Environmental Impact on Remanufacturing Wind Turbines  

NASA Astrophysics Data System (ADS)

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

Sosa Skrainka, Manuel R.

342

Development of methodology for horizontal axis wind turbine dynamic analysis  

NASA Technical Reports Server (NTRS)

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.

Dugundji, J.

1982-01-01

343

Aerodynamic Analyses of Different Wind Turbine Blade Profiles  

NASA Astrophysics Data System (ADS)

For thousands of years mankind is utilizing wind energy. Increasing world population and increasingly reducing oil reserves and resulting requirement for clean, reliable, renewable energy systems intensifies the requirement for wind energy in long term. Nowadays, wind turbines are used for transforming that energy into electrical and mechanical energy. In order to gain from a wind turbine economically in maximum amounts performance data based on blade cross-section characteristics must be found. In the present study angle of attacks for 4 various blade profiles, Re numbers and correlations between lift and drag rates are investigated. Snack 2.0, computer software has been used for the calculation of lift, drag, moment and minimum pressure coefficients. For all evaluated blade profiles and all Re rates in the provided highest sliding rates most convenient angle of attack was determined in the range of 3° and 9°. According to lift-drag correlation in constant drag value as long as Re rate is higher also lift is intensified. Highest drag rates found corresponding to Re 20000.

Kurtulmus, Ferhat; Vardar, Ali; Izli, Nazmi

344

Spatial mapping and attribution of Wyoming wind turbines, 2012  

USGS Publications Warehouse

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).

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

2014-01-01

345

Analysis of wind turbines in yaw  

SciTech Connect

The yaw problems of a three-bladed, downwind, horizontal axis wind turbine are examined in this report. A four-degree-of-freedom system was chosen to model the turbine. Linearized equations of rotor and nacelle motion were developed using the energy method and Lagrange's equations. Quasi-steady blade element and momentum theories were used in developing the axial induction factor and aerodynamic loads. A computer code was developed to obtain the numerical values of coefficients of the equations of motion, thus allowing the cause of yaw instability to be studied. The study indicated that yaw tracking error is primarily caused by tower shadow. However, the wind turbine studied - besides being unstable in yaw under normal operating conditions - has an additional problem in that the nacelle shape contributes to additional instability. Blade coning, in the present design, is inadequate to overcome this instability. The sensitivity of the system stiffness coefficients to the selected input parameters was studied, and results indicate that the system stiffness coefficient is highly sensitive to the coning angle. Increasing the coning angle could significantly increase the stiffness coefficient and lead to improvement of system stability.

Wilson, R.E.; Chaiyapinunt, S.

1983-09-01

346

Structural Dynamic Behavior of Wind Turbines  

NASA Technical Reports Server (NTRS)

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).

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

2009-01-01

347

Analysis of wind turbines in yaw  

NASA Astrophysics Data System (ADS)

The yaw problems of a three-bladed, downwind, horizontal axis wind turbine are examined. A four-degree-of-freedom system was chosen to model the turbine. Linearized equations of rotor and nacelle motion were developed using the energy method and Lagrange's equations. Quasi-steady blade element and momentum theories were used in developing the axial induction factor and aerodynamic loads. A computer code was developed to obtain the numerical values of coefficients of the equations of motion, thus allowing the cause of yaw instability to be studied. The study indicated that yaw tracking error is primarily caused by tower shadow. However, the wind turbine studied, besides being unstable in yaw under normal operating conditions, has an additional problem in that the nacelle shape contributes to additional instability. Blade coming, in the present design, is inadequate to overcome this instability. The sensitivity of the system stiffness coefficients to the selected input parameters was studied, and results indicate that the system stiffness coefficient is highly sensitive to the coning angle. Increasing the coning angle could significantly increase the stiffness coefficient and lead to improvement of system stability.

Wilson, R. E.; Chaiyapinunt, S.

1983-09-01

348

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

Federal Register 2010, 2011, 2012, 2013

...FWS-R9-FHC-2011-N061; 94300-1122-0000-Z2] Wind Turbine Guidelines Advisory Committee...Service (Service), will host a Wind Turbine Guidelines Advisory Committee...Alternate Designated Federal Officer, Wind Turbine Guidelines Advisory...

2011-04-01

349

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

Federal Register 2010, 2011, 2012, 2013

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

2012-06-01

350

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

Federal Register 2010, 2011, 2012, 2013

...94300-1122-0000-Z2] RIN 1018-AX45 Wind Turbine Guidelines Advisory Committee...Service (Service), will host a Wind Turbine Guidelines Advisory Committee...Alternate Designated Federal Officer, Wind Turbine Guidelines Advisory...

2011-09-01

351

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

Federal Register 2010, 2011, 2012, 2013

...FWS-R9-FHC-2011-N137; 94300-1122-0000-Z2] Wind Turbine Guidelines Advisory Committee...Service (Service), will host a Wind Turbine Guidelines Advisory Committee...Alternate Designated Federal Officer, Wind Turbine Guidelines Advisory...

2011-07-01

352

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

Federal Register 2010, 2011, 2012, 2013

...FWS-R9-FHC-2011-N061; 94300-1122-0000-Z2] Wind Turbine Guidelines Advisory Committee...Service (Service), will host a Wind Turbine Guidelines Advisory Committee...Alternate Designated Federal Officer, Wind Turbine Guidelines Advisory...

2011-04-11

353

Dynamic Wind Loads and Vortex Structures in the Wake of a Wind Turbine  

Microsoft Academic Search

We report an experimental study to characterize the dynamic wind loads and evolution of wake vortex flow structures downstream of a horizontal axis wind turbine (HAWT). The experiments were conducted in a wind tunnel with a wind turbine model placed in a boundary layer flow developed over rough and smooth surfaces in order to study the effects of roughness and

Hui Hu; Zifeng Yang; Partha Sarkar

2010-01-01

354

Chances in wind energy: a probalistic approach to wind turbine fatigue design  

Microsoft Academic Search

Wind is becoming an ever more important source of renewable energy: installed wind turbine power now stands at 60,000 MW worldwide, providing 0.6% of world electricity demand. Still it is important that the cost of wind energy is brought down further, which means that wind turbines must be designed to be exactly as strong as necessary, but no stronger. Hence

Herman Frederik Veldkamp

2006-01-01

355

Wind tunnel investigation of the wake structure within small wind turbine farms.  

National Technical Information Service (NTIS)

The primary aim of the work reported here was to obtain comprehensive data on the mean and turbulent flow within wind farms of horizontal axis wind turbines. Wakes within wind farms of 15 wind turbine models have been investigated in some detail in the la...

U. Hassan

1993-01-01

356

Wind Turbine Generator System Power Performance Test Report for the Gaia-Wind 11-kW Wind Turbine  

SciTech Connect

This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. It is a power performance test that the National Renewable Energy Laboratory (NREL) conducted on the Gaia-Wind 11-kW small wind turbine.

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

2009-12-01

357

Certification for Small Wind Turbine Installers: What's the Hang Up.  

National Technical Information Service (NTIS)

Several programs have been implemented to support the advancement of a professional, mature small wind industry and to ensure that this industry moves forward in a sustainable direction. The development of a standard for small wind turbine systems and the...

F. Oteri K. Sinclair

2012-01-01

358

Fatigue Evaluation of Wind Turbines. Part 1: Theoretical Background.  

National Technical Information Service (NTIS)

The theoretical background for the computation of fatigue damage in horizontal axis wind turbines is described. Input data are meteorological statistics of mean wind velocities, autospectra, two point coherence- and phase spectra of turbulence, together w...

A. Raab B. Winzell U. Hjorth

1982-01-01

359

Fatigue case study and reliability analyses for wind turbines.  

National Technical Information Service (NTIS)

Modern wind turbines are fatigue critical machines used to produce electrical power. To insure long term, reliable operation, their structure must be optimized if they are to be economically viable. The fatigue and reliability projects in Sandia's Wind En...

H. J. Sutherland, P. S. Veers

1994-01-01

360

Wind Turbine Drivetrain Condition Monitoring-An Overview.  

National Technical Information Service (NTIS)

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 t...

S. Sheng W. Yang

2013-01-01

361

Large-eddy simulation of wind-turbine wakes: Evaluation of turbine parameterizations  

Microsoft Academic Search

Large-eddy simulation (LES) offers a great potential to study the effects of turbulent atmospheric boundary layer flow on the performance of wind turbines and wind farms. The accuracy of the simulations, however, hinges on our ability to parameterize subgrid-scale (SGS) turbulent fluxes as well as turbine-induced forces. In this study, we investigate the performance of LES in simulations of wind-turbine

Fernando Porte-Agel; Yu-Tin Wu; Hao Lu; Leonardo Chamorro

2010-01-01

362

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

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

363

Optimization of wind turbine design for SWECS  

NASA Astrophysics Data System (ADS)

Current research to optimize wind turbine designs centers on the most important parameter, the useful lifetime of the rotor assembly. A rotor design which promises to extend the lifetime of the full rotor assembly is discussed. That design improvement includes the integration of a teetered rotor hub and a delta-3 angle. This design concept was proven in helicopter and rotor craft applications. The adaptation to wind turbines was the primary task of this appropriate technology utilization project. Test rotors, incorporating the teetering hub, delta-3 angle design, were constructed and tested. The research model provides a full range of settings for a complete evaluation of the relevant parameters; e.g., the delta-3 angle is variable from +70 to -70(0), the rotor position may be varied fore and aft of the teeter axis, the teeter spring rate is continuously variable, also the teeter and yaw stops are adjustable. The use of a dc generator permits the rotor to change angular speed with wind speed. The lack of a yaw drive allows the rotor to display its own passive yawing rates and accommodation factors as a function of delta-3 angle, rotor axis position, and teeter spring rate settings.

Bryant, P. J.

1983-08-01

364

Laboratory-scale experiments on wind turbine nacelle movement estimation  

NASA Astrophysics Data System (ADS)

The effect of nacelle motion should be considered when calculating the wind speed relative to the wind turbine structure, which is essential in wind turbine control and performance testing. A Kalman filter approach is applied to estimate the nacelle motion of a wind turbine. Information from several accelerometers and strain gauges which are installed on the wind turbine tower is combined with the Kalman filter. An optimization algorithm is used to choose the optimal locations for strain gauge and accelerometer installation. A laboratory-scale experimental rig which mimics the tower and nacelle of the wind turbine is constructed to evaluate the performance of the proposed estimator algorithm. The usefulness of the proposed algorithm is validated by these laboratory-scale experimental results.

Nam, Yoonsu; Yoon, Tai Jun

2009-11-01

365

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

DOEpatents

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.

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

2008-06-03

366

Wind Turbines Make Waves: Why Some Residents near Wind Turbines Become Ill  

ERIC Educational Resources Information Center

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…

Havas, Magda; Colling, David

2011-01-01

367

Reference Wind Speed Distributions and Height Profiles for Wind Turbine Design and Performance Evaluation Applications.  

National Technical Information Service (NTIS)

The purpose of this report is to provide a set of reference or standard values of wind profiles, wind speed distributions and their effects on wind turbine performance for engineering design applications. Based on measured Weibull distribution parameters,...

A. Mikhail C. G. Justus W. R. Hargraves

1976-01-01

368

MOD-0 wind turbine dynamics test correlations  

NASA Technical Reports Server (NTRS)

The behavior of the teetered, downwind, free yaw, MOD-0 wind turbine, as represented by NASA dynamic test data, was used to support confidence in the Hamilton Standard computer code simulations. Trim position, performance at trim, and teeter response as predicted by the computer codes were compared to test results. Using the computer codes, other possible configurations for MOD-0 were investigated. Several new test configurations are recommended for exploring free yaw behavior. It is shown that eliminating rotor tilt and optimizing cooling and blade twist can contribute to good free yaw behavior and stability. The effects of rotor teeter, teeter gravity balance, inflow and other physical and operating parameters were also investigated.

Brooks, B. M.

1981-01-01

369

Fatigue of fiberglass wind turbine blade materials  

NASA Astrophysics Data System (ADS)

Fatigue behavior for a variety of generic materials used in wind turbine blades was explored. Coupon testing was carried out under constant amplitude tensile fatigue loading to beyond 10(exp 7) cycles for most materials. Unidirectional materials performed close to expectations despite fiber misalignment. Materials with triaxial (0/plus or minus 45) reinforcement showed greater fatigue sensitivity than expected, but lifetime trends flattened at high cycles. The uniaxial and triaxial materials could be normalized to a single S-N lifetime trend for each case. Results include the effects of differing matrix materials, manufacturing methods, reinforcement structure, and ply terminations.

Mandell, J. F.; Reed, R. M.; Samborsky, D. D.

1992-08-01

370

Fatigue reliability of wind turbine components  

NASA Astrophysics Data System (ADS)

Fatigue life estimates for wind turbine components can be extremely variable due to both inherently random and uncertain parameters. A structural reliability analysis is used to qualify the probability that the fatigue life will fall short of a selected target. Reliability analysis also produces measures of the relative importance of the various sources of uncertainty and the sensitivity of the reliability to each input parameter. The process of obtaining reliability estimates is briefly outlined. An example fatigue reliability calculation for a blade joint is formulated; reliability estimates, importance factors, and sensitivities are produced. Guidance in selecting distribution functions for the random variables used to model the random and uncertain parameters is also provided.

Veers, P. S.

371

Model 0A wind turbine generator FMEA  

NASA Technical Reports Server (NTRS)

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.

Klein, William E.; Lalli, Vincent R.

1989-01-01

372

Fluid-Structure Interaction Analysis of Wind Turbines  

NASA Astrophysics Data System (ADS)

Countries around the world are putting substantial effort into the development of wind energy technologies. The urgent need of renewable energy puts pressure on the wind energy industry research and development to enhance the current wind generation capabilities and decrease the associated costs. Currently most wind turbine aerodynamics and aeroelasticity simulations are performed using low-fidelity methods. These methods are simple to implement and fast to execute; however, the cases involving important features, such as unsteady flow, turbulence, and details of the wind turbine geometry, are beyond their range of applicability. In this dissertation, we introduce a paradigm shift in wind turbine analysis by developing 3D, complex geometry, time-dependent, multi-physics modeling procedures for wind turbine fluid-structure interaction (FSI). The proposed framework consists of a collection of numerical methods combined into a single framework for FSI modeling and simulation of wind turbines at full scale. The use of the Navier-Stokes equations of incompressible flows for wind turbine aerodynamics is validated against experimental data. The structural modeling of the composite blades is based on the Kirchhoff-Love thin shell theory discretized using isogeometric analysis. The coupled FSI formulation is derived using the augmented Lagrangian approach and accommodates non-matching fluid-structure interface discretizations. The challenges of fluid-structural coupling and the handling of computational domains in relative motion are discussed, and the FSI computations of a 5 MW offshore baseline wind turbine are shown.

Hsu, Ming-Chen

373

Applications of an improved equivalent wind method for the aggregation of DFIG wind turbines  

Microsoft Academic Search

Recently wind energy has developed at a fast pace, and it is necessary to develop equivalent models to represent dynamic behaviors of wind farms on power system. The equivalent wind method has been investigated for the aggregation of DFIG wind turbines. The detailed procedure for the calculation of equivalent wind has been analyzed. The necessity of classifying incoming winds has

Z. J. Meng; F. Xue; Kang Chang; Maosheng Ding; Jun Zhang; Li Xiang; Jiafeng Shi; Xiaoyu Li

2011-01-01

374

Improving the performance of the equivalent wind method for the aggregation of DFIG wind turbines  

Microsoft Academic Search

Recently wind energy has developed at a fast pace, and it is necessary to develop equivalent models to represent dynamic behaviors of wind farms on power system. The equivalent wind method has been investigated for the aggregation of DFIG wind turbines. The detailed procedure for the calculation of equivalent wind has been analyzed. The necessity of classifying incoming winds has

Z. J. Meng; F. Xue

2011-01-01

375

An Investigation of the Equivalent Wind Method for the Aggregation of DFIG Wind Turbines  

Microsoft Academic Search

Recently wind energy has developed at a fast pace, and it is necessary to develop equivalent models to represent dynamic behaviors of wind farms on power system. The equivalent wind method has been investigated for the aggregation of DFIG wind turbines. The detailed procedure for the calculation of equivalent wind has been analyzed. The necessity of classifying incoming winds has

Z. J. Meng; F. Xue

2010-01-01

376

Using Dynamically Coupled Turbine\\/Wind Simulations to Investigate the Influence of Atmospheric Turbulence in Turbine Wake Recovery  

Microsoft Academic Search

In order to increase our efficiency of energy capture in wind farms, optimize turbine arrangements, and adapt wind-turbine technology to optimal performance in common atmospheric conditions such as low level jets (LLJ), it is critical to understand the dynamic interactions between turbulence and multiple wind turbines. Ambient atmospheric turbulence interacts with spinning turbines producing the critical mechanism for the recovery

R. Linn; E. Koo; N. D. Kelley; B. Jonkman; J. K. Lundquist; J. Canfield

2010-01-01

377

Control of Wind Turbines: Past, Present, and Future  

SciTech Connect

We review the objectives and techniques used in the control of horizontal axis wind turbines at the individual turbine level, where controls are applied to the turbine blade pitch and generator. The turbine system is modeled as a flexible structure operating in the presence of turbulent wind disturbances. Some overview of the various stages of turbine operation and control strategies used to maximize energy capture in below rated wind speeds is given, but emphasis is on control to alleviate loads when the turbine is operating at maximum power. After reviewing basic turbine control objectives, we provide an overview of the common basic linear control approaches and then describe more advanced control architectures and why they may provide significant advantages.

Laks, J. H.; Pao, L. Y.; Wright, A. D.

2009-01-01

378

(Construction of a wind turbine). Final report  

SciTech Connect

A wind powered electrical generator was built by industrial arts students working in electricity, woodworking, and metal technology facilities. The blades were originally aluminum frames covered with sailcloth. These were replaced with hand-carved laminated basswood blades. Original plans called for a bullet and downwind propeller, but this was replaced with an upwind propeller and an aft-mounted tailfin. A V-belt and pulley drive transmits power from the turbine and a motorcycle brake stops the machine during high winds and/or for safe servicing. The original 13 volt, 105 amp alternator was replaced by a 12 volt, 100 amp dc generator. Publicity and dissemination events are listed as well as expenditures. (LEW)

Devine, L.E.

1982-03-22

379

Wind turbine generator with improved operating subassemblies  

DOEpatents

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.

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

1985-01-01

380

Wind turbine trailing edge aerodynamic brakes  

SciTech Connect

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).

Migliore, P G [National Renewable Energy Lab., Golden, CO (United States); Miller, L S [Wichita State Univ., KS (United States). Dept. of Aerospace Engineering; Quandt, G A

1995-04-01

381

Combination wind turbine generator and solar hot water system  

Microsoft Academic Search

This demonstration combined two renewable sources of energy, wind and solar, to meet the needs for a hot water system and electrical generation. A new and unique wind blade design called a Helical Wind Turbine was used. The solar hot water system used was commercially produced. The project has demonstrated that wind generators are feasible in Harford County, Maryland.

J. L. Jr

1983-01-01

382

Individual pitch control of wind turbine based on loads estimation  

Microsoft Academic Search

The use of wind energy for generating electricity has been constantly and rapidly increasing over last few decades and this growth is expected to continue. In order to enable even greater role of wind energy in power production wind turbinespsila sizes and rated powers must increase. As wind turbines grow in size they are subjected to extreme loads and fatigue

M. Jelavic; V. Petrovic; N. Peric

2008-01-01

383

Identification of wind turbine model for individual pitch controller design  

Microsoft Academic Search

The use of wind power has been increasing rapidly over last few decades and according to all predictions this trend is likely to continue. At the same time need for better cost effectiveness of wind power plants has stimulated growth in wind turbinespsila size and rated power. As wind turbines grow in size they are subject to extreme structural loads

V. Petrovic; M. Jelavic; N. Peric

2008-01-01

384

Real-time simulation of BLDC-based wind turbine emulator using RT-LAB  

Microsoft Academic Search

A novel wind turbine emulator (WTE) based on a torque controlled Brushless DC (BLDC) motor is presented, which can emulate the steady-state and dynamic characteristics of an actual wind turbine. Variable wind speeds, turbine inertia and torque oscillation caused by tower shadow and wind shear are all considered in the construction of the actual wind turbine model and the torque

Honghao Guo; Bo Zhou; Jichen Li; Fangshun Cheng; Le Zhang

2009-01-01

385

Maximum power extraction from a small wind turbine using 4-phase interleaved boost converter  

Microsoft Academic Search

This paper describes a 4-phase interleaved boost converter in a small wind turbine application. The boost converter is placed between the wind turbine and the load and is controlled to extract the maximum power from wind turbine. The boost converter duty ratio adjusted, based on the wind speed and rotor speed values, so that the wind turbine would be operated

Liqin Ni; D. J. Patterson; J. L. Hudgins

2009-01-01

386

How I Home-Built an Electricity Producing Wind Turbine  

NSDL National Science Digital Library

This site has step-by-step instructions on how to build a wind turbine with parts you can purchase from the hardware store and e-bay. The website includes photographs and text which illustrate how to build the wind turbine.

Davis, Michael

2010-10-20

387

Impact of wind turbine controller strategy on deloaded operation  

Microsoft Academic Search

In the past, wind turbines were only required to provide limited ancillary services and they could inject as much power as they wanted in the grid. Nowadays the impact of wind turbines is no longer negligible. Therefore, many system operators have put in place grid codes which require renewable energy sources support the power system and provide ancillary services. These

P. Venne; X. Guillaud

2009-01-01

388

Experimental demonstration of the Diffuser Augmented Wind Turbine concept  

Microsoft Academic Search

The Diffuser Augmented Wind Turbine (DAWT) is one of the advanced concepts being investigated to improve the economics of wind energy conversion systems (WECS). Very compact diffusers using boundary layer control have been examined experimentally. Small scale model testing with screens and centerbodies to simulate a real turbine was used to choose a baseline diffuser configuration. This design is a

B. L. Gilbert; K. M. Foreman

1978-01-01

389

Stochastic Models for Strength of Wind Turbine Blades using Tests  

Microsoft Academic Search

The structural cost of wind turbine blades is dependent on the values of the partial safety factors which re- flect the uncertainties in the design values, including statistical uncertainty from a limited number of tests. This paper presents a probabilistic model for ultimate and fatigue strength of wind turbine blades especially considering the influence of prior knowledge and test results

Henrik Stensgaard Toft; John Dalsgaard Sørensen

390

Wind turbine load reduction by rejecting the periodic load disturbances  

Microsoft Academic Search

For the cost per kilowatt hour to be decreased, the trend in offshore wind turbines is to increase the rotor diameter as much as possible. The increasing dimensions have led to a relative increase of the loads on the wind turbine structure; thus, it is necessary to react to disturbances in a more detailed way, e.g. each blade separately. The

I. Houtzager; Jan-Willem van Wingerden; Michel Verhaegen

2012-01-01

391

Towards Data-Driven Control for Modern Wind Turbines  

Microsoft Academic Search

Further developments in data-driven control techniques for the load reduction of modern wind turbines can achieve an increased lifetime of components and make the scaling to larger rotor diameters possible, and therefore improve the cost effectiveness of modern wind turbines. Also the success of future rotor designs will heavily depend for their operation on new developments in active control technologies.

I. Houtzager

2011-01-01

392

Lightning protection for wind turbine blades and bearings  

Microsoft Academic Search

The protection of wind turbines from lightning damage is increasingly important as they increase in size and are placed in locations where access to carry out repairs may be difficult. As blades are the most common attachment point of lightning, they must be adequately protected. In addition, the passage of lightning current through wind turbine bearings introduces a risk of

Ian Cotton; Nick Jenkins; Krishnan Pandiaraj

2001-01-01

393

Effects of Wind Turbine Farms on ATC Radar.  

National Technical Information Service (NTIS)

The UK Government supports the introduction of wind turbine farms as part of its alternative energy strategy. However, Ministry of Defense (MoD) guidelines restrict planning consent for wind turbine farms within line of sight (LoS) from Primary Surveillan...

2005-01-01

394

Radar-Cross-Section Reduction of Wind Turbines. Part 1.  

National Technical Information Service (NTIS)

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...

B. C. Brock J. A. Paquette J. J. McDonald P. G. Clem S. E. Allen W. E. Patitz

2012-01-01

395

Wind turbine electromagnetic scatter modelling using physical optics techniques  

Microsoft Academic Search

A software programme has been developed at EMRAD to model the Radar Cross Section (RCS) of complex objects such as wind turbines. The model is based on Physical Optics simplifying the computational complexity of the model. Initial validation experiments show encouraging results. The model predictions can then be used to compute the effects of wind turbines on nearby radio systems.

H. S. Dabis; R. J. Chignell

1999-01-01

396

Failure Modes and Effects Analysis (FMEA) for wind turbines  

Microsoft Academic Search

The Failure Modes and Effects Analysis (FMEA) method has been used to study the reliability of many different power generation systems. This paper now applies that method to a wind turbine (WT) system using a proprietary software reliability analysis tool. Comparison is made between the quantitative results of an FMEA and reliability field data from real wind turbine systems and

H. Arabian-Hoseynabadi; H. Oraee; P. J. Tavner

2010-01-01

397

Assessment of lightning stroke incidence to modern wind turbines  

Microsoft Academic Search

An assessment of lightning stroke incidence to modern wind turbines will be presented in this paper. Wind turbines present tall isolated objects, often located in regions with high thunderstorm activity. This leads to their high lightning incidence, which means that they tend to get struck by lightning very often, compared to other structures. This fact, combined with the intense grow

Petar Sarajcev

2010-01-01

398

Control of wind turbine generators connected to power systems  

Microsoft Academic Search

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

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

1978-01-01

399

General review of the MOSTAS computer code for wind turbines  

NASA Technical Reports Server (NTRS)

The MOSTAS computer code for wind turbine analysis is reviewed, and techniques and methods used in its analyses are described. Impressions of its strengths and weakness, and recommendations for its application, modification, and further development are made. Basic techniques used in wind turbine stability and response analyses for systems with constant and periodic coefficients are reviewed.

Dungundji, J.; Wendell, J. H.

1981-01-01

400

Wind turbines emulating inertia and supporting primary frequency control  

Microsoft Academic Search

The increasing penetration of variable-speed wind turbines in the electricity grid will result in a reduction of the number of connected conventional power plants. This will require changes in the way the grid frequency is controlled. In this letter, a method is proposed to let variable-speed wind turbines emulate inertia and support primary frequency control. The required power is obtained

Johan Morren; Sjoerd W. H. de Haan; Wil L. Kling; J. A. Ferreira

2006-01-01

401

Fault ride-through capability of DFIG wind turbines  

Microsoft Academic Search

This paper concentrates on the fault ride-through capability of doubly fed induction generator (DFIG) wind turbines. The main attention in the paper is, therefore, drawn to the control of the DFIG wind turbine and of its power converter and to the ability to protect itself without disconnection during grid faults. The paper provides also an overview on the interaction between

Anca D. Hansen; Gabriele Michalke

2007-01-01

402

Understanding the unbalanced-voltage problem in wind turbine generation  

Microsoft Academic Search

Most wind turbines are equipped with line-connected induction generators. Induction generators are very attractive as wind turbine generators due to their low cost, ruggedness, and the need for little or no maintenance. At constant frequency, the induction generator operates in a small range of speeds and, therefore, it operates with a small range of slips with respect to synchronous speed.

E. Muljadi; D. Yildirim; T. Batan; C. P. Butterfield

1999-01-01

403

Representing wind turbine electrical generating systems in fundamental frequency simulations  

Microsoft Academic Search

Increasing numbers of wind turbines are being erected. In the near future, they may start to influence the dynamics of electrical power systems by interacting with conventional generation equipment and with loads. The impact of wind turbines on the dynamics of electrical power systems therefore becomes an important subject, studied by means of power system dynamics simulations. Various types of

J. G. Slootweg; H. Polinder; W. L. Kling

2003-01-01

404

DIRECT-COUPLED PERMANENT MAGNET WIND TURBINE DESIGN CONSIDERATIONS  

Microsoft Academic Search

The paper presents the design procedure of a permanent magnet generator for a 20 kW wind turbine prototype. This work has been developed in the frame of a research project funded by the General Secretariat for Research and Technology of Greece concerning the design and construction of a gear-less wind turbine for both autonomous and interconnected operation with the electrical

S. A. Papathanassiou; A. G. Kladas; M. P. Papadopoulos

405

Using partial safety factors in wind turbine design and testing  

Microsoft Academic Search

This paper describes the relationship between wind turbine design and testing in terms of the certification process. An overview of the current status of international certification is given along with a description of limit-state design basics. Wind turbine rotor blades are used to illustrate the principles discussed. These concepts are related to both International Electrotechnical Commission and Germanischer Lloyd design

W. D. Musial; C. Butterfield

1997-01-01

406

DOE/NASA Lewis large wind turbine program  

NASA Technical Reports Server (NTRS)

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).

Thomas, R. L.

1982-01-01

407

Wind turbine design codes: A preliminary comparison of the aerodynamics  

Microsoft Academic Search

The National Wind Technology Center of the National Renewable Energy Laboratory is comparing several computer codes used to design and analyze wind turbines. The first part of this comparison is to determine how well the programs predict the aerodynamic behavior of turbines with no structural degrees of freedom. Without general agreement on the aerodynamics, it is futile to try to

Marshall L. Buhl; Alan D. Wright; James L. Tangler

1997-01-01

408

Simulation studies on imbalance faults of wind turbines  

Microsoft Academic Search

This paper presents the use of simulations to study imbalance faults of wind turbines. The dynamics of a model wind turbine are simulated in three different scenarios, i.e., normal operating conditions, blade imbalance, and aerodynamic asymmetry, using TurbSim and FAST. Blade imbalance is simulated by scaling the mass density of one blade which created an uneven distribution of mass with

Derek J. Gardels; Wei Qiao; Xiang Gong

2010-01-01

409

PMSG Wind Turbine Performance Analysis During Short Circuit Faults  

Microsoft Academic Search

Due to the increasing price of fossil fuels and the security concerns of the nuclear energy, electricity generation using wind turbines has recently attracted significant attention after a period of neglect. Among different types of wind turbine generators, PM synchronous generators (PMSG) offer better performance due to higher efficiency and less maintenance since they do not have rotor current and

A. Abedini; A. Nasiri

2007-01-01

410

Actuator Surface Model for Wind Turbine Flow Computations  

Microsoft Academic Search

Summary The paper presents a new numerical technique for simulating wind turbine flows. The method, denoted as the actuator surface technique, consists of a three-dimensional Navier-Stokes solver and a body force distributed along the blade surfaces of a wind turbine. The force at each airfoil section is obtained from tabulated lift and drag coefficients, which depend on local angle of

Wen Zhong Shen; Jens Nørkær Sørensen; Jian Hui Zhang

411

High Tip Speed Operation for Offshore Wind Turbines  

Microsoft Academic Search

Summary The operation of large offshore wind turbines at high rotational speeds is investigated with focus on rotor aerodynamics, performance for the extended operational range and the potential for tower top mass reductions. 2D aerodynamic investigations were carried out with the program XFOIL on the NACA 63415 airfoil. Several 5 MW wind turbine rotors were designed to operate at tip

Andreas Knauer; Tor David Hanson

412

Research on pitch control of floating offshore wind turbines  

Microsoft Academic Search

This article mainly focuses on individual pitch control of floating offshore wind turbines. Regarding to the power and movement control of offshore wind turbines, we apply experts PID control to the design of controller. In order to verify the feasibility of controller, simulation experiments have been run on FAST. The result shows individual pitch control technique can effectively reduce pitching

Hongche Guo; Xiaoping Lu; Tianyu Qiu

2012-01-01

413

Fault detection of large scale wind turbine systems  

Microsoft Academic Search

Fault diagnosis of large scale wind turbine systems has received much attention in the recent years. Effective fault prediction would allow for scheduled maintenance and for avoiding catastrophic failures. Thus the availability of wind turbines can be enhanced and the cost for maintenance can be reduced. In this paper, we consider the sensor and actuator fault detection issue for large

Xiukun Wei; Lihua Liu

2010-01-01

414

Fault estimation of large scale wind turbine systems  

Microsoft Academic Search

Fault diagnosis of large scale wind turbine systems has received much attention in the recent years. Effective fault prediction would allow for scheduled maintenance and for avoiding catastrophic failures. Thus the availability of wind turbines can be enhanced and the cost for maintenance can be reduced. In this paper, we consider the sensor and actuator fault detection issue for large

Wei Xiukun; Liu Lihua

2010-01-01

415

Monitoring of small wind turbine blade using FBG sensors  

Microsoft Academic Search

Dynamic behavior of a small wind turbine blade has been analyzed experimentally. Arrays of Fiber Bragg Grating (FBG) sensors and strain gauges were used to extract mode shapes of a small wind turbine blade made of fiber reinforced plastic (FRP). The root of the blade was fixed by a cantilever system developed for this study and dynamic strains from the

Chang-Hwan Kim; Insu Paek; Neungsoo Yoo

2010-01-01

416

How to squeeze more kilowatts from wind turbines  

Microsoft Academic Search

Proposals to make wind turbines more efficient range from inexpensive taping of a seam on the Danish blades to costly projects that would replace entire rotor systems. Other efficiency steps would alter the pitch of the blades, use different lubricants, extend hubs, etc. Only those turbines in the direct wind stream achieve a high efficiency. Paybacks for corrective measures should

Gipe

1987-01-01

417

PLC Based Test Platform for Wind Turbine Gearbox  

Microsoft Academic Search

Wind turbine gearbox is one of the most important and most expensive components of wind turbine. Once installed, it is difficult to repair. Therefore, it needs effective experiments during its design and production to meet the strict quality requirements. The test platform adopts Closure Design, which enables it to experiment two gearbox products at the same time. And thanks to

Zou Xinyu

2010-01-01

418

A floating platform of concrete for offshore wind turbine  

Microsoft Academic Search

A floating platform concept is introduced in this paper for offshore wind turbine. A vertical cylinder on the top of an elliptical sphere forms the principal configuration of the platform. The analysis of the dynamic performance of an example platform with 5 MW wind turbine by means of the well-established linear theory for the dynamics of marine constructions in waves

Jianbo Hua

2011-01-01

419

Wind turbine wake properties from Doppler lidar measurements  

NASA Astrophysics Data System (ADS)

Wake properties were estimated from the High-Resolution Doppler Lidar (HRDL) measurements during the Turbine Wake and Inflow Characterization Study (TWICS) in the spring of 2011. Velocity deficit, wake downwind extent, and wake meandering were obtained by detailed analysis of both lidar vertical-slice scans, performed straddling along the lidar-turbine centerline, and lidar conical scans, performed in narrow, nearly horizontal sectors that include the wind turbine inflow, and its wake at four levels. Simultaneous measurements of inflow and turbine outflow were corrected by terrain and wind direction to obtain mean wake properties. It has been found out that an operating wind turbine generates a wake with the maximum velocity deficit varying from 20% to 70% extending up to 10 rotor diameters downstream of the turbine, depending on the wind strength and atmospheric turbulence. Details including images and animations of the wake behavior will be presented.

Pichugina, Y.; Banta, R. M.; Brewer, A.; Lundquist, J. K.

2012-12-01

420

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

NASA Astrophysics Data System (ADS)

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, , 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.

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

2013-08-01

421

Spatial mapping and attribution of Wyoming wind turbines  

USGS Publications Warehouse

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.

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

2010-01-01

422

Parameter Study of LM 9.7 M Wind Turbine Blades. Measurement of Efficiency Curves and Breaking Proficiency of an LM 9.7 M Wind Turbine Blade Mounted on a WM 20 S Wind Turbine Produced by Wind Matic.  

National Technical Information Service (NTIS)

Measurements of performance and breaking efficiency of a LM 9.7 m wind turbine blade mounted on a WM 20 S wind turbine produced by the firm Wind Matic in Denmark. Measurements were made, taking account of wind speed and direction, electric power productio...

J. B. Gjerding

1988-01-01

423

Locations and attributes of wind turbines in Colorado, 2011  

USGS Publications Warehouse

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.

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

2013-01-01

424

Locations and attributes of wind turbines in New Mexico, 2011  

USGS Publications Warehouse

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.

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

2013-01-01

425

Avian Hearing and the Avoidance of Wind Turbines  

SciTech Connect

This report provides a complete summary of what is known about basic hearing capabilities in birds in relation to the characteristics of noise generated by wind turbines. It is a review of existing data on bird hearing with some preliminary estimates of environmental noise and wind turbine noise at Altamont Pass, California, in the summer of 1999. It is intended as a resource in future discussions of the role that hearing might play in bird avoidance of turbines.

Dooling, R.

2002-06-01

426

Wind turbines: is there a human health risk?  

PubMed

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

Roberts, Jennifer D; Roberts, Mark A

2013-04-01

427

Duration Test Report for the Ventera VT10 Wind Turbine  

SciTech Connect

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.

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

2013-06-01

428

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

USGS Publications Warehouse

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.

Diffendorfer, Jay E.; Compton, Roger W.

2014-01-01

429

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

PubMed

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

Diffendorfer, Jay E; Compton, Roger W

2014-01-01

430

Smoothing effects of distributed wind turbines. Part 1. Coherence and smoothing effects at a wind farm  

NASA Astrophysics Data System (ADS)

Recently there has been a marked increase in wind power generation. From a power system point of view, because a wind turbine is an intermittent generator with large output fluctuation, any increase in the number of wind turbines gives rise to concerns about the adverse effects of wind turbines on power quality. The smoothing effects of wind turbine output fluctuation are of great importance in assessing the impacts of a large number of wind turbines. This article examines smoothing effects at a wind farm. First it presents a summary of wind measurements taken at two locations with six masts over a period of 1 year on both flat and complex terrain. Then the spatial coherence of wind speed is analysed, paying special attention to its dependence on the distance between observation points, wind direction, wind velocity and fluctuation frequency. Approximation equations for coherence of frequency and distance are obtained by applying Davenport's expression to the observed data. Second, coherence between turbine output at a wind farm is investigated; the results indicate that coherence for wind speed and turbine output shows a considerable resemblance. The article also examines smoothing effects at a wind farm using power spectral density through a theoretical approach. The study proves that smoothing effects can be approximated with a lowpass filter and that the effects at a wind farm should not be taken into account for periods of more than 10 min in case of assessing them on the safe side. Copyright

Nanahara, Toshiya; Asari, Masahiro; Sato, Takamitsu; Yamaguchi, Koji; Shibata, Masaaki; Maejima, Tsutomu

2004-04-01

431

An Induction Motor Based Wind Turbine Emulator  

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

432

Synchronization of wind turbine generators against an infinite bus under gusting wind conditions  

NASA Technical Reports Server (NTRS)

Studies of synchronizing a wind turbine generator against an infinite bus are performed on a digital computer. In the digital simulation, wind gusts of different magnitudes and durations are hypothesized. Prior to the synchronization, differences of the frequency and phase position between voltages of the alternator and the bus are also included in the simulation. Solutions for rotor speed, generator power angle, electromagnetic torque, wind turbine torque, wind turbine blade pitch angle, and armature current are simulated and presented graphically. The ERDA-NASA 100-kW wind turbine is used as a case study. The results so obtained will thus have immediate applications.

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

1978-01-01

433

Annoyance, detection and recognition of wind turbine noise.  

PubMed

Annoyance, recognition and detection of noise from a single wind turbine were studied by means of a two-stage listening experiment with 50 participants with normal hearing abilities. In-situ recordings made at close distance from a 1.8-MW wind turbine operating at 22 rpm were mixed with road traffic noise, and processed to simulate indoor sound pressure levels at LAeq 40 dBA. In a first part, where people were unaware of the true purpose of the experiment, samples were played during a quiet leisure activity. Under these conditions, pure wind turbine noise gave very similar annoyance ratings as unmixed highway noise at the same equivalent level, while annoyance by local road traffic noise was significantly higher. In a second experiment, listeners were asked to identify the sample containing wind turbine noise in a paired comparison test. The detection limit of wind turbine noise in presence of highway noise was estimated to be as low as a signal-to-noise ratio of -23 dBA. When mixed with local road traffic, such a detection limit could not be determined. These findings support that noticing the sound could be an important aspect of wind turbine noise annoyance at the low equivalent levels typically observed indoors in practice. Participants that easily recognized wind-turbine(-like) sounds could detect wind turbine noise better when submersed in road traffic noise. Recognition of wind turbine sounds is also linked to higher annoyance. Awareness of the source is therefore a relevant aspect of wind turbine noise perception which is consistent with previous research. PMID:23624007

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

2013-07-01

434

Tribological advancements for reliable wind turbine performance.  

PubMed

Wind turbines have had various limitations to their mechanical system reliability owing to tribological problems over the past few decades. While several studies show that turbines are becoming more reliable, it is still not at an overall acceptable level to the operators based on their current business models. Data show that the electrical components are the most problematic; however, the parts are small, thus easy and inexpensive to replace in the nacelle, on top of the tower. It is the tribological issues that receive the most attention as they have higher costs associated with repair or replacement. These include the blade pitch systems, nacelle yaw systems, main shaft bearings, gearboxes and generator bearings, which are the focus of this review paper. The major tribological issues in wind turbines and the technological developments to understand and solve them are discussed within. The study starts with an overview of fretting corrosion, rolling contact fatigue, and frictional torque of the blade pitch and nacelle yaw bearings, and references to some of the recent design approaches applied to solve them. Also included is a brief overview into lubricant contamination issues in the gearbox and electric current discharge or arcing damage of the generator bearings. The primary focus of this review is the detailed examination of main shaft spherical roller bearing micropitting and gearbox bearing scuffing, micropitting and the newer phenomenon of white-etch area flaking. The main shaft and gearbox are integrally related and are the most commonly referred to items involving expensive repair costs and downtime. As such, the latest research and developments related to the cause of the wear and damage modes and the technologies used or proposed to solve them are presented. PMID:20855322

Kotzalas, Michael N; Doll, Gary L

2010-10-28

435

ERCOT's Dynamic Model of Wind Turbine Generators: Preprint  

SciTech Connect

By the end of 2003, the total installed wind farm capacity in the Electric Reliability Council of Texas (ERCOT) system was approximately 1 gigawatt (GW) and the total in the United States was about 5 GW. As the number of wind turbines installed throughout the United States increases, there is a greater need for dynamic wind turbine generator models that can properly model entire power systems for different types of analysis. This paper describes the ERCOT dynamic models and simulations of a simple network with different types of wind turbine models currently available.

Muljadi, E.; Butterfield, C. P.; Conto, J.; Donoho, K.

2005-08-01

436

Wind Turbine Certification and Type Certification Guideline for the Certification of Wind Turbines, Edition 2003 with Supplement 2004  

Microsoft Academic Search

Certification of wind turbines or components is state-of-the-art and a must in most places around the world. Furthermore certification to harmonised requirements is an active support of export. Therefore it is important for manufacturers, banks and insurances of wind turbines and components to know the different certification processes as well as guidelines. The procedures to obtain Type and Project Certificates

Mike Woebbeking; Christian Nath; Germanischer Lloyd

437

Wind turbine power tracking using an improved multimodel quadratic approach.  

PubMed

In this paper, an improved multimodel optimal quadratic control structure for variable speed, pitch regulated wind turbines (operating at high wind speeds) is proposed in order to integrate high levels of wind power to actively provide a primary reserve for frequency control. On the basis of the nonlinear model of the studied plant, and taking into account the wind speed fluctuations, and the electrical power variation, a multimodel linear description is derived for the wind turbine, and is used for the synthesis of an optimal control law involving a state feedback, an integral action and an output reference model. This new control structure allows a rapid transition of the wind turbine generated power between different desired set values. This electrical power tracking is ensured with a high-performance behavior for all other state variables: turbine and generator rotational speeds and mechanical shaft torque; and smooth and adequate evolution of the control variables. PMID:20434153

Khezami, Nadhira; Benhadj Braiek, Naceur; Guillaud, Xavier

2010-07-01

438

Wind turbine reliability : a database and analysis approach.  

SciTech Connect

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.

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

2008-02-01

439

AGGREGATED MODELLING OF WIND PARKS WITH VARIABLE SPEED WIND TURBINES IN POWER SYSTEM DYNAMICS SIMULATIONS  

Microsoft Academic Search

More and more wind turbines are made part of electrical power systems, in order to reduce the adverse environmental impact of conventional electrical power generation. A tendency to erect these turbines in wind parks, that are connected to the high voltage transmission grid can be observed. To facilitate the investigation of the impact of a wind park on the dynamics

J. G. Slootweg; S. W. H. de Haan; H. Polinder; W. L. Kling

2002-01-01

440

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

Microsoft Academic Search

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

B. Loyd; W. L. Harris

1995-01-01

441

Wind Tunnel Tests on a Wind Turbine with Contractor and Diffuser Arrangement  

Microsoft Academic Search

This article illustrates the improved wind energy capture of a standard small-scale wind turbine with a novel contractor and diffuser. The contractor and diffuser arrangement is used to accelerate the air-flow across the turbine's blade system and has been optimised using computational fluid dynamics. The results obtained from wind tunnel experiments show a 43% increase in power output for the

J Fletcher; F Wang; L Bai; J Whiteford; D Cullen

2007-01-01

442

Statistical analysis of wind characteristics at candidate wind-turbine sites  

Microsoft Academic Search

Accurate prediction for a wind turbine facility performance is dependent on appropriate wind characteristics data. This report presents preliminary recommendations of appropriate data recording procedures for initial site evaluation and for large machine performance evaluation. Conclusions are based on autocorrelation, autospectrum persistence, cross-correlation, and coherence analysis of a limited sample of wind speed and turbine power data collected at the

Corotis

1982-01-01

443

Use of turbine inertia for power smoothing of wind turbines with a DFIG  

Microsoft Academic Search

Fluctuating power is of serious concern in grid connected wind systems and energy storage systems are being developed to help alleviate this. This paper describes how additional energy storage can be provided within the existing wind turbine system by allowing the turbine speed to vary over a wider range. It also addresses the stability issue due to the modified control

L. Ran; J. R. Bumby; P. J. Tavner

2004-01-01

444

A flexible turbine blade for passive blade pitch control in wind turbines  

Microsoft Academic Search

We present a flexible wind turbine blade that effectively pitches itself according to variable wind loading. In contrast to rigid turbine blades, where active controls are often required to pitch blades, the flexible or morphing blade adjusts its geometry passively, eliminating the need for costly electromechanical systems. We analyze the airfoil using a robust and accurate fluid-structure interaction routine, and

David MacPhee; Asfaw Beyene

2011-01-01

445

Impedance-based structural health monitoring of wind turbine blades  

NASA Astrophysics Data System (ADS)

Wind power is a fast-growing source of non-polluting, renewable energy with vast potential. However, current wind turbine technology must be improved before the potential of wind power can be fully realized. Wind turbine blades are one of the key components in improving this technology. Blade failure is very costly because it can damage other blades, the wind turbine itself, and possibly other wind turbines. A successful damage detection system incorporated into wind turbines could extend blade life and allow for less conservative designs. A damage detection method which has shown promise on a wide variety of structures is impedance-based structural health monitoring. The technique utilizes small piezoceramic (PZT) patches attached to a structure as self-sensing actuators to both excite the structure with high-frequency excitations, and monitor any changes in structural mechanical impedance. By monitoring the electrical impedance of the PZT, assessments can be made about the integrity of the mechanical structure. Recently, advances in hardware systems with onboard computing, including actuation and sensing, computational algorithms, and wireless telemetry, have improved the accessibility of the impedance method for in-field measurements. This paper investigates the feasibility of implementing such an onboard system inside of turbine blades as an in-field method of damage detection. Viability of onboard detection is accomplished by running a series of tests to verify the capability of the method on an actual wind turbine blade section from an experimental carbon/glass/balsa composite blade developed at Sandia National Laboratories.

Pitchford, Corey; Grisso, Benjamin L.; Inman, Daniel J.

2007-05-01

446

The Selection of a Suitable Maintenance Strategy for Wind Turbines  

Microsoft Academic Search

Common maintenance strategies applied to wind turbines include 'Time-Based' which involves carrying out maintenance tasks at predetermined regular-intervals and 'Failure- Based' which entails using a wind turbine until it fails. However, the consequence of failure of critical components limits the adequacy of these strategies to support the current commercial drivers of the wind industry. Reliability-Centred Maintenance (RCM) is a technique

Jesse A. Andrawus; Mohammed Kishk; Allan Adam

2006-01-01

447

Grid code requirements concerning connection and operation of wind turbines in Germany  

Microsoft Academic Search

This paper discusses issues of German grid codes relating to wind turbines. With the high utilization of wind power a simultaneous loss of several thousand MW wind generation became a realistic scenario in the German power system. Therefore, the main requirements concern the fault ride through capability of wind turbines. Accordingly, disconnection of wind turbines and wind farms above 15

I. Erlich; U. Bachmann

2005-01-01

448

Active disturbance rejection based pitch control of variable speed wind turbine  

Microsoft Academic Search

Pitch system is a complicated nonlinear system disturbed by many uncertainties and is a key part of wind turbine system. When wind speed exceeds rated cut-in speed, pitch angle is changed to control wind power conversion efficiency, thus capturing rated power from wind and protecting wind turbine from damage. In this paper, based on the analysis of wind turbine aerodynamic,

Wenjing Zhang; Hongze Xu

2011-01-01

449

A user's manual for the program TRES4: Random vibration analysis of vertical-axis wind turbines in turbulent winds  

NASA Astrophysics Data System (ADS)

TRES4 is a software package that works with the MSC/NASTRAN finite element analysis code to conduct random vibration analysis of vertical-axis wind turbines. The loads on the turbine are calculated in the time domain to retain the nonlinearities of stalled aerodynamic loadings. The loads are transformed into modal coordinates to reduce the number of degrees of freedom. Power spectra and cross spectra of the loads are calculated in the modal coordinate system. These loads are written in NASTRAN Bulk Data format to be read and applied in a random vibration analysis by NASTRAN. The resulting response is then transformed back to physical coordinates to facilitate user interpretation.

1994-03-01

450

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

Microsoft Academic Search

This report examines the complex interactions between atmospheric stability and turbine-induced wakes on downwind turbine wind speed and power production at a West Coast North American multi-MW wind farm. Wakes are generated when the upwind flow field is distorted by the mechanical movement of the wind turbine blades. This has two consequences for downwind turbines: (1) the downwind turbine encounters

S Wharton; J K Lundquist; N Marjanovic

2012-01-01

451

Seismic analysis of wind turbines in the time domain  

NASA Astrophysics Data System (ADS)

The analysis of wind turbine loading associated with earthquakes is clearly important when designing for and assessing the feasibility of wind farms in seismically active regions. The approach taken for such analysis is generally based on codified methods which have been developed for the assessment of seismic loads acting on buildings. These methods are not able to deal properly with the aeroelastic interaction of the dynamic motion of the wind turbine structure with either the wind loading acting on the rotor blades or the response of the turbine controller. This article presents an alternative approach, which is to undertake the calculation in the time domain. In this case a full aeroelastic model of the wind turbine subject to turbulent wind loading is further excited by ground motion corresponding to the earthquake. This capability has been introduced to the GH Bladed wind turbine simulation package. The software can be used to compute the combined wind and earthquake loading of a wind turbine given a definition of the external conditions for an appropriate series of load cases. This article discusses the method and presents example results. Copyright

Witcher, D.

2005-01-01

452

Simulation for Grid Connected Wind Turbines with Fluctuating  

NASA Astrophysics Data System (ADS)

This paper establishes the whole dynamic model of wind turbine generator system which contains the wind speed model and DFIG wind turbines model .A simulation sample based on the mathematical models is built by using MATLAB in this paper. Research are did on the performance characteristics of doubly-fed wind generators (DFIG) which connected to power grid with three-phase ground fault and the disturbance by gust and mixed wind. The capacity of the wind farm is 9MW which consists of doubly-fed wind generators (DFIG). Simulation results demonstrate that the three-phase ground fault occurs on grid side runs less affected on the stability of doubly-fed wind generators. However, as a power source, fluctuations of the wind speed will run a large impact on stability of double-fed wind generators. The results also show that if the two disturbances occur in the meantime, the situation will be very serious.

Ye, Ying; Fu, Yang; Wei, Shurong

453

Influences of Atmospheric Stability State on Wind Turbine Aerodynamic Loadings  

NASA Astrophysics Data System (ADS)

Wind turbine power and loadings are influenced by the structure of atmospheric turbulence and thus on the stability state of the atmosphere. Statistical differences in loadings with atmospheric stability could impact controls, blade design, etc. Large-eddy simulation (LES) of the neutral and moderately convective atmospheric boundary layer (NBL, MCBL) are used as inflow to the NREL FAST advanced blade-element momentum theory code to predict wind turbine rotor power, sectional lift and drag, blade bending moments and shaft torque. Using horizontal homogeneity, we combine time and ensemble averages to obtain converged statistics equivalent to ``infinite'' time averages over a single turbine. The MCBL required longer effective time periods to obtain converged statistics than the NBL. Variances and correlation coefficients among wind velocities, turbine power and blade loadings were higher in the MCBL than the NBL. We conclude that the stability state of the ABL strongly influences wind turbine performance. Supported by NSF and DOE.

Vijayakumar, Ganesh; Lavely, Adam; Brasseur, James; Paterson, Eric; Kinzel, Michael

2011-11-01

454

Safety and Function Test Report for the SWIFT Wind Turbine  

SciTech Connect

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.

Mendoza, I.; Hur, J.

2013-01-01

455

Duration Test Report for the SWIFT Wind Turbine  

SciTech Connect

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.

Mendoza, I.; Hur, J.

2013-01-01

456

Augmented adaptive control of a wind turbine in the presence of structural modes  

Microsoft Academic Search

Wind turbines operate in highly turbulent environments resulting in aerodynamic loads that can easily excite turbine structural modes, potentially causing component fatigue and failure. Two key technology drivers for turbine manufacturers are increasing turbine up time and reducing maintenance costs. Since the trend in wind turbine design is towards larger, more flexible turbines with lower frequency structural modes, manufacturers will

Susan A. Frost; Mark J. Balas; Alan D. Wright

2010-01-01

457

A simple method of estimating wind turbine blade fatigue at potential wind turbine sites  

NASA Astrophysics Data System (ADS)

This paper presents a technique of estimating blade fatigue damage at potential wind turbine sites. The cornerstone of this technique is a simple model for the blade's root flap bending moment. The model requires as input a simple set of wind measurements which may be obtained as part of a routine site characterization study. By using the model to simulate a time series of the root flap bending moment, fatigue damage rates may be estimated. The technique is evaluated by comparing these estimates with damage estimates derived from actual bending moment data; the agreement between the two is quite good. The simple connection between wind measurements and fatigue provided by the model now allows one to readily discriminate between damaging and more benign wind environments.

Barnard, J. C.; Wendell, L. L.

1995-06-01

458

A simple method of estimating wind turbine blade fatigue at potential wind turbine sites  

SciTech Connect

This paper presents a technique of estimating blade fatigue damage at potential wind turbine sites. The cornerstone of this technique is a simple model for the blade`s root flap bending moment. The model requires as input a simple set of wind measurements which may be obtained as part of a routine site characterization study. By using the model to simulate a time series of the root flap bending moment, fatigue damage rates may be estimated. The technique is evaluated by comparing these estimates with damage estimates derived from actual bending moment data; the agreement between the two is quite good. The simple connection between wind measurements and fatigue provided by the model now allows one to readily discriminate between damaging and more benign wind environments.

Barnard, J.C.; Wendell, L.L.

1995-06-01

459

Axial flux, modular, permanent-magnet generator with a toroidal winding for wind turbine applications  

Microsoft Academic Search

Permanent-magnet generators have been used for wind turbines for many years. Many small wind turbine manufacturers use direct-drive permanent-magnet generators. For wind turbine generators, the design philosophy must cover the following characteristics: low cost; light weight; low speed; high torque; and variable speed generation. The generator is easy to manufacture and the design can be scaled up for a larger

E. Muljadi; C. P. Butterfield; Yih-Huei Wan

1998-01-01

460

Full-scale modal wind turbine tests: comparing shaker excitation with wind excitation  

Microsoft Academic Search

\\u000a The test facilities at the National Wind Technology Center (NWTC) of the National Renewable Energy Laboratory (NREL) include\\u000a a three-bladed Controls Advanced Research Turbine (CART3). The CART3 is used to test new control schemes and equipment for\\u000a reducing loads on wind turbine components. As wind turbines become lighter and more flexible to reduce costs, novel control\\u000a mechanisms are necessary to

Richard Osgood; Gunjit Bir; Heena Mutha; Bart Peeters; Marcin Luczak; Gert Sablon

461

Wind Characteristics Analyses and Determination of Appropriate Wind Turbine for Amasra—Black Sea Region, Turkey  

Microsoft Academic Search

In this study, wind characteristics of Amasra were analyzed with hourly wind data collected between 1997 and 2006. Wind characteristics such as monthly average mean speeds, power densities, turbulence intensities, maximum gust, and prevailing wind directions were identified. Weibull distribution model was used to determine energy output of thirty commercial wind turbines ranging from 335 to 3000 kW. Estimated mean

S. A. Akda?; Ö. Güler

2010-01-01

462

Aggregated dynamic model for wind farms with doubly fed induction generator wind turbines  

Microsoft Academic Search

As a result of increasing wind farms penetration in power systems, the wind farms begin to influence power system, and thus the modelling of wind farms has become an interesting research topic. Nowadays, doubly fed induction generator based on wind turbine is the most widely used technology for wind farms due to its main advantages such as high-energy efficiency and

Luis M. Fernández; Francisco Jurado; José Ramón Saenz

2008-01-01

463

Design considerations for medium-frequency power transformers in offshore wind farms  

Microsoft Academic Search

In a recently proposed converter system for offshore wind farms, single-phase medium-frequency (MF) transformers replace the conventional three-phase line-frequency transformers that convert the electricity from the wind turbine generators to high voltage. MF operation allows a reduction of the transformer size and weight, thus leading to a compact and efficient design, which minimizes the installation and maintenance costs. This paper

Stephan Meier; Tommy Kjellqvist; Staffan Norrga; Hans-Peter Nee

2009-01-01

464

Vibration Based Structural Health Monitoring for Utility Scale Wind Turbines  

NASA Astrophysics Data System (ADS)

Structural health monitoring (SHM) is a process of implementing a damage detection strategy for a mechanical system. Wind turbine machinery stands to benefit from SHM significantly as the ability to detect early stages of damage before serious malfunction or collapse reduces the overall operating costs of wind power projects. Vibration analysis of dynamic structural response is an approach to SHM that has been successfully applied to mechanical and civil systems and shows promise for wind turbine application due to availability of instruments, ease of installation, and overall affordability. This study presents the development of vibration based wind turbine structural health monitoring through experimental analysis of an operating wind turbine. A database of acquired vibration response signals detailing over 3 hours of turbine operation was assembled and a Daubachies 6th order wavelet was used to perform a 12 level discrete wavelet decomposition such that general trends and patterns within the signals could be identified. After determining response behavior of a healthy turbine, a novel vibration based SHM scheme is developed based on findings from experimental work. Specific interest has been paid to monitoring yaw and braking systems as they have been identified as problematic. With further development this vibration scheme can be applied by wind farm operators to reduce downtime and failure frequency of utility scale wind turbines.

Bassett, Kyle

465

Aeroelastic stability analysis of wind turbines using an eigenvalue approach  

NASA Astrophysics Data System (ADS)

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

Hansen, M. H.

2004-04-01

466

Recent results from data analysis of dynamic stall on wind turbine blades  

Microsoft Academic Search

Wind turbines are subjected to dynamic loading from a variety of different sources. Wind shear and turbulence cause time-varying inflow that results in unsteady airloads. Tower shadow, upwind turbine wakes, and yaw angles also introduce unsteady inflow to wind turbine rotors. Wind turbine designers must predict these loads accurately in order to adequately design blades, hubs, and the remaining support

C. P. Butterfield; D. Simms; S. Huyer

1992-01-01

467

A summary of the fatigue properties of wind turbine materials  

NASA Astrophysics Data System (ADS)

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 aeroplane. 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. This article reviews the fatigue data that have been developed especially for wind turbines. Major sections are devoted to the properties developed for metals (primarily aluminium), wood and fibreglass. Special emphasis is placed on the fibreglass discussion because this material is currently the material of choice for wind turbine blades. The article focuses on the data developed in the US, but cites European references that provide important insights. Published in 2000 by John Wiley & Sons, Ltd.

Sutherland, Herbert J.

2000-01-01

468

Aeroelastic analysis of the Darrieus wind turbine  

SciTech Connect

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.

Meyer, E.E.

1982-01-01

469

Wind turbine rotor hub and teeter joint  

DOEpatents

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.

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

1994-10-11

470

Computational study of horizontal axis wind turbines  

SciTech Connect

A hybrid Navier-Stokes potential flow methodology for modeling three-dimensional unsteady viscous flow over horizontal axis wind turbine configurations is presented. In this approach, the costly viscous flow equations are solved only in a small viscous flow region surrounding the rotor. The rest of the flow field is modeled using a potential flow methodology. The tip vortices are modeled using a free wake approach, which allows the vortices to deform and interact with each other. Sample results are presented for two rotor configurations tested by the National Renewable Energy Laboratory. Comparisons with experimental data, full Navier-Stokes simulations and blade element momentum theory are given to establish the efficiency and accuracy of the present scheme.

Xu, G.; Sankar, L.N.

2000-02-01

471

Structural health monitoring of wind turbines  

SciTech Connect

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.

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

1997-09-01

472

A fatigue approach to wind turbine control  

NASA Astrophysics Data System (ADS)

Conventional design of wind turbine controllers is focused on speed and produced electric power. As fatigue loads is an important design consideration, the resulting design is evaluated also with respect to the fatigue loads inflicted on the turbine structure. This is normally done by performing simulations using tools like FLEX, HAWC or FAST, followed by rainflow counting in the resulting time series. This procedure constitutes an iterative design procedure involving realisations of the stress processes in order to obtain the time series needed for fatigue estimates. The focus of this paper is the elimination of the need for process realisation. To this end, known techniques for approximative fatigue load assesment based on the spectral moments of the inflicted stress histories are applied. Assuming a linearised system model, we present a novel scheme for efficient computation of these spectral moments. The scheme is applied to obtain rapid evaluation of cost functions including fatigue loads, hereby allowing efficient numerical optimisation of the controller. Three different controller design examples are given, all defined directly in terms of component life times.

Hammerum, K.; Brath, P.; Poulsen, N. K.

2007-07-01

473

Active Power Control Strategies of DFIG Wind Turbines  

Microsoft Academic Search

This paper is devoted to the active power control of DFIG wind turbines. An adaptation of the usual power set point control has been proposed in order to improve the transient behavior for high wind speeds. Several strategies for the active power control are studied. In the high wind speed range, the pitch control seems the most relevant to release

Noël A. Janssens; Guillaume Lambin; Nicolas Bragard

2007-01-01

474

Seabed instability simplified model and application in offshore wind turbine  

Microsoft Academic Search

The offshore wind power is increasingly developed, it is essential to study the design technology of the offshore wind turbine foundation, which is crucial to reduce the construction cost of the offshore wind farm. In the design of marine pile foundations, the evaluation of wave-induced seabed stability is quite significant. Based on the mechanical properties of seabed, this article firstly

Zhang Yong-li; Li Jie

2009-01-01

475

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

NASA Technical Reports Server (NTRS)

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.

Strock, O. J.

1980-01-01

476

ASR11 radar performance assessment over a wind turbine farm  

Microsoft Academic Search

Wind turbines are known to interfere with radar systems, including Air Traffic Control (ATC) radar. Despite this being a known issue, relatively few quantitative studies have been performed which analyze the performance of ATC radar systems impacted by wind farms. For this study, an Apache helicopter flew two sets of varied flight paths above two wind farm in proximity to

Christopher Lute; William Wieserman

2011-01-01

477

Evaluation of a wind turbine electric power generator  

NASA Technical Reports Server (NTRS)

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.

Swim, W. B.

1981-01-01

478

Forecast of faults in a wind turbine gearbox  

Microsoft Academic Search

The maintenance costs associated with wind turbines assumes an important weight in the operation of wind parks. The main objective of wind farms operators is to run their parks most economically, to increase their profits. An adequate maintenance planning is essential to an effective operating costs reduction, compared with traditional maintenance techniques. Tools to detect the onset of mechanical and

R. F. Mesquita Brandao; J. A. Beleza Carvalho; F. P. Maciel Barbosa

2012-01-01

479

Small Wind Turbine power curves obtained in laboratory  

Microsoft Academic Search

This paper describes the methodology to obtain power curves of Small Wind Turbine Generators (SWTG) in laboratory. Power generator system includes a fan, wind tunnel, SWTG, power monitor, weather sensors, battery and a PC. A wind tunnel was adapted after an axial fan in order to reduce turbulence. Power curves were draw for different cases; varying the distance and the

Wei-Ching Chen; Sheng-Chung Tzeng; P. K. Valdivia; Yi-Chang Yang

2010-01-01

480

Optimization of wind turbine vane manufacture based on queuing theory  

Microsoft Academic Search

Wind turbine vane is the key components of wind power generators effectively capture the wind. RTM is a manufacture technology of advanced composite materials, low cost, medium batch blade. Some random factors often lead to the production schedule can not be predetermined program normally. It can help reduce production costs that with the start-up costs were study of production scheduling

Qing-hui Dai; Sha Li

2011-01-01

481

Quantifying the hurricane risk to offshore wind turbines.  

PubMed

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

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

2012-02-28

482

Dynamic wind loads and wake characteristics of a wind turbine model in an atmospheric boundary layer wind  

NASA Astrophysics Data System (ADS)

An experimental study was conducted to characterize the dynamic wind loads and evolution of the unsteady vortex and turbulent flow structures in the near wake of a horizontal axis wind turbine model placed in an atmospheric boundary layer wind tunnel. In addition to measuring dynamic wind loads (i.e., aerodynamic forces and bending moments) acting on the wind turbine model by using a high-sensitive force-moment sensor unit, a high-resolution digital particle image velocimetry (PIV) system was used to achieve flow field measurements to quantify the characteristics of the turbulent vortex flow in the near wake of the wind turbine model. Besides conducting "free-run" PIV measurements to determine the ensemble-averaged statistics of the flow quantities such as mean velocity, Reynolds stress, and turbulence kinetic energy (TKE) distributions in the wake flow, "phase-locked" PIV measurements were also performed to elucidate further details about evolution of the unsteady vortex structures in the wake flow in relation to the position of the rotating turbine blades. The effects of the tip-speed-ratio of the wind turbine model on the dynamic wind loads and wake flow characteristics were quantified in the terms of the variations of the aerodynamic thrust and bending moment coefficients of the wind turbine model, the evolution of the helical tip vortices and the unsteady vortices shedding from the blade roots and turbine nacelle, the deceleration of the incoming airflows after passing the rotation disk of the turbine blades, the TKE and Reynolds stress distributions in the near wake of the wind turbine model. The detailed flow field measurements were correlated with the dynamic wind load measurements to elucidate underlying physics in order to gain further insight into the characteristics of the dynamic wind loads and turbulent vortex flows in the wakes of wind turbines for the optimal design of the wind turbines operating in atmospheric boundary layer winds.

Hu, Hui; Yang, Zifeng; Sarkar, Partha

2012-05-01

483

Fatigue case study and reliability analyses for wind turbines  

NASA Astrophysics Data System (ADS)

Modern wind turbines are fatigue critical machines used to produce electrical power. To insure long term, reliable operation, their structure must be optimized if they are to be economically viable. The fatigue and reliability projects in Sandia's Wind Energy Program are developing the analysis tools required to accomplish these design requirements. The first section of the paper formulates the fatigue analysis of a wind turbine using a cumulative damage technique. The second section uses reliability analysis for quantifying the uncertainties and the inherent randomness associated with turbine performance and the prediction of service lifetimes. Both research areas are highlighted with typical results.

Sutherland, Herbert J.; Veers, Paul S.

484

Locations and attributes of wind turbines in New Mexico, 2009  

USGS Publications Warehouse

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.

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

2011-01-01

485

Locations and attributes of wind turbines in Colorado, 2009  

USGS Publications Warehouse

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.

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

2011-01-01

486

High temperature co-axial winding transformers  

NASA Technical Reports Server (NTRS)

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 densit