WorldWideScience
 
 
1

Vortex wind turbine  

Energy Technology Data Exchange (ETDEWEB)

The Vortex Wind Turbine Project is intended to prove or disprove the viability of Vortex Air Inducement in a cross wind axis turbine of vertical design. Experimentation was cautiously pursued with various models of proposed Vortex Wind turbines. A realization of the Vortex principle with other known devices, was incorporated throughout the search, for correct application to a cross-wind axis vertical turbine. Initial findings of structural design negatives, dominated much of the Vortex wind turbine work. The vertical axis turbine with a Vortex inducing housing indicated two major problems. The first area of structural concern is that the turbine design is such that many critical stress components are of a cantilever type. The second area of concern is that a housing needed to produce the proper anticipated Vortex action is costly. The effectiveness of Vortex action in a cross-wind vertical turbine has not as yet been established.

Raymond, F.E.

1981-10-01

2

Wind turbine  

Science.gov (United States)

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

3

Wind conditions for wind turbine design proposals for revision of the IEC 1400-1 standard  

Energy Technology Data Exchange (ETDEWEB)

The International Electrotechnical Commission (IEC) TC88 formed a subcommittee to re-evaluate the external wind condition models defined in the standard for `Wind Turbine Generator Systems, Part I: Safety Requirements` 1400-1. These models define design turbulence conditions, extreme gust transients, extreme wind direction transients and extreme shear transients as well as other normal and extreme conditions. The TC88 subcommittee solicited extreme wind condition data from countries throughout the world reporting such parameters as maximum gust magnitudes, minimum gust rise times, and extreme wind shears. These data were used to modify the IEC models to be more representative of typical field conditions. Some data used for comparison together with the new models are presented

Stork, C.H.J. [Riva Calzoni, Via E. Ponente 72, 40033 Bologna (Italy); Butterfield, C.P. [National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, CO (United States); Holley, W. [Consultant, 3731 Oak Brook Court, Pleasanton, CA (United States); Madsen, P.H.; Jensen, P.H. [Risoe National Laboratory, Frederiksborgvej 399, 4000 Roskilde (Denmark)

1998-04-01

4

Wind turbines  

Energy Technology Data Exchange (ETDEWEB)

A wind turbine is described which has at least one blade having a fixed portion and a portion rotatable relative thereto about the blade axis. Rotation of the latter portion is between a normal pitch position, in which it enhances turbine rotation, and an altered pitch position, in which it causes the speed of the turbine to be reduced. A hydraulic system including an actuator drives the rotatable portion towards the normal pitch position when the hydraulic system is pressurised. A safety valve in the hydraulic system is located within the blade. Upon rotation of the blade above a permitted speed, the valve opens, thereby depressurising the hydraulic system and permitting the rotating blade portion to be urged to the altered pitch position.

Ratcliffe, H.

1987-08-19

5

Wind turbine noise diagnostics  

Energy Technology Data Exchange (ETDEWEB)

This presentation proposed a self-consistent model for broad-band noise emitted from modern wind turbines. The simple source model was consistent with the physics of sound generation and considered the unique features of wind turbines. Although the acoustics of wind turbines are similar to those of conventional propellers, the dimensions of wind turbines pose unique challenges in diagnosing noise emission. The general features of the sound field were deduced. Source motion and source directivity appear to be responsible for amplitude variations. The amplitude modulation is likely to make wind-turbine noise more audible, and may be partly responsible for annoyance that has been reported in the literature. Acoustic array data suggests that broad-band noise is emitted predominantly during the downward sweep of each rotor blade. Source motion and source directivity account for the observed pattern. Rotor-tower interaction effects are of lesser importance. Predicted amplitude modulation ranges from 1 dB to 6dB. 2 refs., 9 figs.

Richarz, W. [Aerocoustics Engineering Ltd., Toronto, ON (Canada); Richarz, H.

2009-07-01

6

Wind turbine noise diagnostics  

International Nuclear Information System (INIS)

[en] This presentation proposed a self-consistent model for broad-band noise emitted from modern wind turbines. The simple source model was consistent with the physics of sound generation and considered the unique features of wind turbines. Although the acoustics of wind turbines are similar to those of conventional propellers, the dimensions of wind turbines pose unique challenges in diagnosing noise emission. The general features of the sound field were deduced. Source motion and source directivity appear to be responsible for amplitude variations. The amplitude modulation is likely to make wind-turbine noise more audible, and may be partly responsible for annoyance that has been reported in the literature. Acoustic array data suggests that broad-band noise is emitted predominantly during the downward sweep of each rotor blade. Source motion and source directivity account for the observed pattern. Rotor-tower interaction effects are of lesser importance. Predicted amplitude modulation ranges from 1 dB to 6dB. 2 refs., 9 figs.

2009-01-01

7

A proposed metric for assessing the potential of community annoyance from wind turbine low-frequency noise emissions  

Energy Technology Data Exchange (ETDEWEB)

Given our initial experience with the low-frequency, impulsive noise emissions from the MOD-1 wind turbine and their impact on the surrounding community, the ability to assess the potential of interior low-frequency annoyance in homes located near wind turbine installations may be important. Since there are currently no universally accepted metrics or descriptors for low-frequency community annoyance, we performed a limited program using volunteers to see if we could identify a method suitable for wind turbine noise applications. We electronically simulated three interior environments resulting from low-frequency acoustical loads radiated from both individual turbines and groups of upwind and downwind turbines. The written comments of the volunteers exposed to these interior stimuli were correlated with a number of descriptors which have been proposed for predicting low-frequency annoyance. The results are presented in this paper. We discuss our modifications of the highest correlated predictor to include the internal dynamic pressure effects associated with the response of residential structures to low-frequency acoustic loads. Finally, we outline a proposed procedure for establishing both a low-frequency ''figure of merit'' for a particular wind turbine design and, using actual measurements, estimate the potential for annoyance to nearby communities. 10 refs., 13 figs., 7 tabs.

Kelley, N.D.

1987-10-05

8

A proposed metric for assessing the potential of community annoyance from wind turbine low-frequency noise emissions  

Science.gov (United States)

Given our initial experience with the low frequency, impulsive noise emissions from the MOD-1 wind turbine and their impact on the surrounding community, the ability to assess the potential of interior low frequency annoyance in homes located near wind turbine installations may be important. Since there are currently no universally accepted metrics or descriptors for low frequency community annoyance, we performed a limited program using volunteers to see if we could identify a method suitable for wind turbine noise applications. We electronically simulated three interior environments resulting from low frequency acoustical loads radiated from both individual turbines and groups of upwind and downwind turbines. The written comments of the volunteers exposed to these interior stimuli were correlated with a number of descriptors which have been proposed for predicting low frequency annoyance. The results are presented in this paper. We discuss our modification of the highest correlated predictor to include the internal dynamic pressure effects associated with the response of residential structures to low frequency acoustic loads. Finally, we outline a proposed procedure for establishing both a low frequency figure of merit for a particular wind turbine design and, using actual measurements, estimate the potential for annoyance to nearby communities.

Kelley, N. D.

1987-11-01

9

Aerodynamics of wind turbines  

CERN Document Server

Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its second edition, it has been entirely updated and substantially extended to reflect advances in technology, research into rotor aerodynamics and the structural response of the wind turbine structure.Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Ele

Hansen, Martin OL

2013-01-01

10

Small wind turbines  

CERN Multimedia

Small Wind Turbines provides a thorough grounding in analysing, designing, building, and installing a small wind turbine. Small turbines are introduced by emphasising their differences from large ones and nearly all the analysis and design examples refer to small turbines.The accompanying software includes MATLAB(R) programs for power production and starting performance, as well as programs for detailed multi-objective optimisation of blade design. A spreadsheet is also given to help readers apply the simple load model of the IEC standard for small wind turbine safety. Small Wind Turbines repr

Wood, David

2011-01-01

11

Aerodynamics of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Wind power is an increasingly significant renewable energy resource, producing no environmentally damaging C0{sub 2} emissions. The efficient production of electricity by wind turbines relies on aerodynamics: aerodynamics of wind turbines provides the fundamental solutions to efficient wind turbine design. Following a historical introduction, Part 1 of Aerodynamics of Wind Turbines is concerned with basic rotor aerodynamics, while Part 2 deals with structural aspects of the wind turbine and calculation of the loads on it. Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element Momentum method is also covered, as are eigenmodes and the dynamic behaviour of a turbine. Aerodynamics of Wind Turbines is an essential reference for both engineering students and others with a professional or academic interest in the physics and technologies behind horizontal axis wind turbines. It will provide a sound understanding of the mechanisms behind the generation of forces on a wind turbine. (author)

Hansen, M.O.L.

2000-06-15

12

Aerodynamics of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Wind power is an increasingly significant renewable energy resource, producing no environmentally damaging CO2 emissions. The efficient production of electricity by wind turbines relies on aerodynamics. Aerodynamics of Wind Turbines provides the fundamental solutions to efficient wind turbine design. Following a historical introduction, Part 1 of Aerodynamics of Wind Turbines is concerned with basic rotor aerodynamics, while Part 2 deals with structural aspects of the wind turbine and calculation of the loads on it. Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element Momentum method is also covered, as are eigenmodes and the dynamic behaviour of a turbine. Aerodynamics of Wind Turbines is an essential reference for both engineering students and others with a professional or academic interest in the physics and technologies behind horizontal axis wind turbines. It will provide a sound understanding of the mechanisms behind the generation of forces on a wind turbine. (author)

Hansen, M.O.L. [Technical University of Denmark (Denmark)

2001-01-01

13

Wind turbine. Windturbine  

Energy Technology Data Exchange (ETDEWEB)

The invention is concerned with a wind turbine for converting wind energy. The turbine consists of a rotor wind vertical rotation shaft and energy converter like electric generator, coupled with this shaft. The rotor runs in bearings. It is intended to support the rotor bearings by pillars. The energy converter is installed in the interior between the wind vanes of the rotor.

Bueltzingsloewen, K. von; Wensien, E.

1981-07-02

14

Wind Turbine Blade Design  

Directory of Open Access Journals (Sweden)

Full Text Available A detailed review of the current state-of-art for wind turbine blade design is presented, including theoretical maximum efficiency, propulsion, practical efficiency, HAWT blade design, and blade loads. The review provides a complete picture of wind turbine blade design and shows the dominance of modern turbines almost exclusive use of horizontal axis rotors. The aerodynamic design principles for a modern wind turbine blade are detailed, including blade plan shape/quantity, aerofoil selection and optimal attack angles. A detailed review of design loads on wind turbine blades is offered, describing aerodynamic, gravitational, centrifugal, gyroscopic and operational conditions.

Peter J. Schubel; Richard J. Crossley

2012-01-01

15

Wind turbine generation statistics  

Energy Technology Data Exchange (ETDEWEB)

The wind turbine output has in principal been calculated via the steady-state performance curve. Four wind turbines were modeled for a study. The relevant parameters utilized in the generation calculations are the rated power (MW), the cut-in (m/s), the rated wind speed (m/s), the cut-out (m/s) and the hub height (m).

Dub, W.; Pape, H.

1983-03-01

16

Editorial - Wind Turbine PHM  

Directory of Open Access Journals (Sweden)

Full Text Available This Special Issue on Wind Turbine Prognostics and Health Management contains 14 excellent papers that highlight a wide range of current research and application topics related to wind turbine PHM. Fault diagnostics is an important aspect of wind turbine PHM. Eight papers included in this special issue deal with fault diagnostics of different parts of a wind turbine. Each of these papers presents different fault diagnostic techniques and sensing technologies.We, the editors, are confident that this special issue containing research papers on wind turbine prognostics and health management with both an academic and industrial focus will push further the wind turbine research PHM and help to bring more advanced PHM technologies into the industrial applications. We would also like to thank the authors for their contributions and express our sincere appreciation to the reviewers for their time and expertise in providing valuable feedback.

David He; Eric Bechhoefer; Abhinav Saxena

2013-01-01

17

Wind Turbines Wake Aerodynamics  

DEFF Research Database (Denmark)

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 conditions. The emphasis is put on measurements in controlled conditions.For the far wake, the survey focusses on both single turbines and wind farm effects, and the experimental and numerical work are reviewed; the main interest is to study how the far wake decays downstream, in order to estimate the effect produced in downstream turbines.The article is further restricted to horizontal axis wind turbines and excludes all other types of turbines.

Vermeer, L.; SØrensen, Jens NØrkær

2003-01-01

18

Wind turbine noise  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this book is to give an overview of state-of-the-art knowledge in the field of wind turbine noise: Chapters: 1. Introduction; 2. Noise and its effects; 3. Introduction to aeroacoustics; 4. Noise mechanisms of wind turbines; 5. Noise prediction; 6. Noise propagation; 7. Measurement of noise and flow field; 8. Noise reduction; 9. Future work. (HW). 88 figs.

Wagner, S. [Stuttgart Univ. (Germany). Inst. fuer Aerodynamik und Gasdynamik; Bareiss, R. [Stuttgart Univ. (Germany). Inst. fuer Aerodynamik und Gasdynamik; Guidati, G. [Stuttgart Univ. (Germany). Inst. fuer Aerodynamik und Gasdynamik

1996-12-01

19

Wind Turbine Blade Design  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A detailed review of the current state-of-art for wind turbine blade design is presented, including theoretical maximum efficiency, propulsion, practical efficiency, HAWT blade design, and blade loads. The review provides a complete picture of wind turbine blade design and shows the dominance of mod...

Peter J. Schubel; Richard J. Crossley

20

Wind turbine technology  

CERN Multimedia

Presents an introduction to the wind turbine technology, which can generate electrical energy with lower costs and zero greenhouse effects. Highlighting limitations, capabilities, and benefits, this text identifies the critical components of a wind turbine and describes the functional capabilities of each component.

Jha, A R

2010-01-01

 
 
 
 
21

Wind turbine acoustics  

Science.gov (United States)

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.

1990-12-01

22

The Tjaereborg wind turbine  

Energy Technology Data Exchange (ETDEWEB)

The cooperation between the Danish Ministry of Energy and the electric utilities started in 1976 with a joint programme directed towards the development of large wind turbines, their siting and integration in the electric grid. The Tjaereborg wind turbine, a 3-bladed, horizontal axis turbine with the blades placed upwind and full span pitch control for power regulation and with the nacelle placed on a concrete tower, was connected to the electric grid in 1988. It finally came into stable operation in late 1990 after severe technical problems with the control system and gearbox. Rotor diameter is 61.1 m, blade profile is NACA 4412-43, blade length - 29 m, solidity - 5.9%, nominal speed at rated power - 22.36 rpm, tilt angle - 3 deg., hub height - 60 m. The design is based on experience gained from NIBE wind turbines. After 2 1/2 years with serious technical problems, in 1991 the turbine was released for automatic unmanned operation for 10117 hours. The general conclusion is that the electricity-producing wind turbines in the multi MW class are a viable technical possibility although the Tjaereborg turbine represents the wind turbine technology of the early eighties. A detailed technical description of this turbine is given in addition to a description of the main problems previously encountered. The system of measurement, site characteristics, operation and production, the power curve, noise emission, optimization of operation and loads are also dealt with in detail. (AB) (32 refs.).

1992-09-01

23

Noise from wind turbines  

International Nuclear Information System (INIS)

[en] Denmark has 3200 wind turbines with an installed maximum capacity of 418MW. The most important Danish research projects into wind turbine noise and the main results are listed. These date from 1983. Two comprehensive studies are currently in progress. The first is an analytical and empirical investigation of aerodynamic noise from wind turbine rotors and has so far dealt mainly with tip noise. The measurement method, using a hard board mounted microphone on the ground near the turbine, is described. Four different tip designs have been tested. Some examples of reference sound power level spectra for three of the designs are presented. During the past two years a computerbased data acquisition system has been used for real-time determination of sound power levels. The second study, which has just commenced, is on annoyance from wind turbine noise. It will include noise measurements, masking calculations and a social survey on the perceived nuisance. (UK)

1992-06-30

24

Wind turbines and infrasound  

International Nuclear Information System (INIS)

This paper provided the results of a study conducted to assess the impacts of wind farm-induced infrasound on nearby residences and human populations. Infrasound occurs at frequencies below those considered as detectable by human hearing. Infrasonic levels caused by wind turbines are often similar to ambient levels of 85 dBG or lower that are caused by wind in the natural environment. This study examined the levels at which infrasound poses a threat to human health or can be considered as an annoyance. The study examined levels of infrasound caused by various types of wind turbines, and evaluated acoustic phenomena and characteristics associated with wind turbines. Results of the study suggested that infrasound near modern wind turbines is typically not perceptible to humans through either auditory or non-auditory mechanisms. However, wind turbines often create an audible broadband noise whose amplitude can be modulated at low frequencies. A review of both Canadian and international studies concluded that infrasound generated by wind turbines should not significantly impact nearby residences or human populations. 17 refs., 2 tabs., 4 figs

2006-01-01

25

Wind turbines and infrasound  

Energy Technology Data Exchange (ETDEWEB)

This paper provided the results of a study conducted to assess the impacts of wind farm-induced infrasound on nearby residences and human populations. Infrasound occurs at frequencies below those considered as detectable by human hearing. Infrasonic levels caused by wind turbines are often similar to ambient levels of 85 dBG or lower that are caused by wind in the natural environment. This study examined the levels at which infrasound poses a threat to human health or can be considered as an annoyance. The study examined levels of infrasound caused by various types of wind turbines, and evaluated acoustic phenomena and characteristics associated with wind turbines. Results of the study suggested that infrasound near modern wind turbines is typically not perceptible to humans through either auditory or non-auditory mechanisms. However, wind turbines often create an audible broadband noise whose amplitude can be modulated at low frequencies. A review of both Canadian and international studies concluded that infrasound generated by wind turbines should not significantly impact nearby residences or human populations. 17 refs., 2 tabs., 4 figs.

Howe, B. [HGC Engineering, Mississauga, ON (Canada)

2006-11-29

26

Extreme Response for Wind Turbines  

DEFF Research Database (Denmark)

The characteristic load on wind turbines during operation are among others dependent on the mean wind speed, the turbulence intensity and type and settings of the control system. The characteristic load during operation is normally estimated by statistical extrapolation of a limited number of simulated 10min time series of the response according to the wind turbine standard IEC 61400-1. However, this method assumes that the individual 10min time series and the extracted peaks from the time series are independent. In the present paper is this assumption investigated based on field measurements and a new method for estimating the characteristic load based on field measurements is proposed.

Toft, Henrik Stensgaard; SØrensen, John Dalsgaard

2009-01-01

27

Wind turbine pitch optimization  

DEFF Research Database (Denmark)

We consider a static wind model for a three-bladed, horizontal-axis, pitch-controlled wind turbine. When placed in a wind field, the turbine experiences several mechanical loads, which generate power but also create structural fatigue. We address the problem of finding blade pitch profiles for maximizing power production while simultaneously minimizing fatigue loads. In this paper, we show how this problem can be approximately solved using convex optimization. When there is full knowledge of the wind field, numerical simulations show that force and torque RMS variation can be reduced by over 96% compared to any constant pitch profile while sacrificing at most 7% of the maximum attainable output power. Using iterative learning, we show that very similar performance can be achieved by using only load measurements, with no knowledge of the wind field or wind turbine model.

Biegel, Benjamin; Juelsgaard, Morten

2011-01-01

28

Noise from wind turbines  

International Nuclear Information System (INIS)

Based on a previous project concerning the calculation of the amount of noise emanating from wind turbine arrays, this one examines the subject further by investigating whether there could be significant differences in the amount of noise made by individual wind turbines in an array, and whether the noise is transmitted in varying directions - so that when it is carried in the same direction as the wind blows it would appear to be louder. The aim was also to determine whether the previously used method of calculation lacked precision. It was found that differences in noise niveaux related to individual wind turbines were insignificant and that noise was not so loud when it was not borne in the direction of the wind. It was necessary to change the method of calculation as reckoning should include the influence of the terrain, wind velocity and distance. The measuring and calculation methods are exemplified and the resulting measurements are presented in detail. (AB).

1992-01-01

29

The Dutch wind turbine industry  

International Nuclear Information System (INIS)

[en] An overview is given of the manufacturers of wind turbines and wind turbine blades in the Netherlands. Special attention is paid to the impact of the Dutch Integral Program Wind energy (IPW) on the developments and activities of the Dutch wind turbine industry. Implementation of wind energy is less than expected. The activities to reduce the prices for wind turbines have not yet resulted in cheaper wind turbines. The efficiency of wind energy however does not only depend on the costs for wind turbines but also on the value adjudged to the electric power from wind energy. Implementation of wind turbines must be better planned based on the condition that the developments in the wind turbine industry should be continued. Problems regarding the selection of sites and licensing procedures have to be solved. 4 tabs

1990-01-01

30

Wind Turbine Blade Design  

Science.gov (United States)

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

31

Vertical axis wind turbines  

Science.gov (United States)

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

2011-03-08

32

Vertical axis wind turbine  

International Nuclear Information System (INIS)

In recent years, the interest in wind turbines with vertical axis noticeably increased. They have some important advantages: low cost, relatively simple structure, reliable packaging system of wind aggregate long period during which require no maintenance, low noise, independence of wind direction, etc.. The relatively low efficiency, however, makes them applicable mainly for small facilities. The work presents a methodology and software for approximately aerodynamic design of wind turbines of this type, and also analyzed the possibility of improving the efficiency of their workflow

2012-01-01

33

Wind turbines and health  

International Nuclear Information System (INIS)

This document summarized the potential health hazards associated with wind turbines, such as noise and low frequency sound, vibration and infrasound; electromagnetic fields (EMF); shadow flicker; and ice throw and structural failure. Various symptoms can be attributed to wind turbines, including dizziness, sleep disruption, and headaches. A review of available research regarding potential health affects to residents living in close proximity to wind turbines showed that the sound level associated with wind turbines at common residential setbacks is not sufficient to damage hearing, but may lead to annoyance and sleep disturbance. Research has shown that wind turbines are not a significant source of EMF exposure, and although shadows caused by the blades may be annoying, they are not likely to cause epileptic seizures at normal operational speeds. The risk of injury from ice throw can be minimized with setbacks of 200 to 400 m. Examples of Canadian wind turbine setback guidelines and regulations were also offered. It was concluded that setbacks and operational guidelines can be utilized in combination to address safety hazards, sound levels, land use issues, and impacts on people. 46 refs., 2 tabs., 2 figs.

2010-01-01

34

European wind turbine catalogue  

International Nuclear Information System (INIS)

The THERMIE European Community programme is designed to promote the greater use of European technology and this catalogue contributes to the fulfillment of this aim by dissemination of information on 50 wind turbines from 30 manufacturers. These turbines are produced in Europe and are commercially available. The manufacturers presented produce and sell grid-connected turbines which have been officially approved in countries where this approval is acquired, however some of the wind turbines included in the catalogue have not been regarded as fully commercially available at the time of going to print. The entries, which are illustrated by colour photographs, give company profiles, concept descriptions, measured power curves, prices, and information on design and dimension, safety systems, stage of development, special characteristics, annual energy production, and noise pollution. Lists are given of wind turbine manufacturers and agents and of consultants and developers in the wind energy sector. Exchange rates used in the conversion of the prices of wind turbines are also given. Information can be found on the OPET network (organizations recognised by the European Commission as an Organization for the Promotion of Energy Technologies (OPET)). An article describes the development of the wind power industry during the last 10-15 years and another article on certification aims to give an overview of the most well-known and acknowledged type approvals currently issued in Europe. (AB).

1994-01-01

35

Wind turbine noise  

International Nuclear Information System (INIS)

[en] Due to a high density in population, wind turbine noise is a serious obstacle in the achievement of the Dutch government's aim: 1000 MW wind power in 2000. This paper presents an overview on the noise issue from the Dutch point of view. (author)

1991-01-01

36

The flora and fauna of a proposed wind turbine site near Royal Road, Prince Edward County, Ontario : preliminary screening of the natural environment  

Energy Technology Data Exchange (ETDEWEB)

Calgary based Vision Quest Windelectric has been given zoning approval to install a 22 MW windfarm in Ontario's Prince Edward County. Following a preliminary screening to determine the effect of the windfarm on the natural environment, the Royal Road Windfarm will be developed in stages with up to 32 turbines. Jacques Whitford Environment Ltd. conducted an environmental study which showed that an exploratory wind turbine in the area is not likely to cause major adverse impacts on local fauna and flora. The proposed location of the wind turbine is not in an important bird area (IBA). An IBA is defined as a site providing essential habitat for one of more species of breeding or non-breeding birds. In 1999, Vision Quest initiated a program to examine bird interactions with wind turbines in southern Alberta. It was shown that most species choose flight paths to avoid turbines. The Royal Road site hosts rare alvars which are naturally open landscapes found in shallow soils on flat limestones. The alvars are subject to seasonal drought and flooding and have specific types of vegetation and animals. Since the exploratory wind turbine will be placed outside the IBA area, its impact on birds will be minimized, and it will have minimal effect on migrant, breeding and wintering birds. It was recommended that monitoring take place at the site during the first year of operation. It is also presumed that the wind turbine will not have any impact on mammals, reptiles and amphibians, or insects. However, it was recommended that more information be gathered on bat movement in the area. If placed appropriately, the wind turbine is not expected to impact on rare plants. It was emphasized that in the past, Vision Quest Windelectric has conducted environmental screening activities, and has acted on recommendations to place wind turbines in locations where environmental impact will be minimized. 26 refs., 5 tabs., 2 figs., 2 appendices.

Holder, M.; Leggett, A. [Jacques Whitford Environment Ltd., Markham, ON (Canada)

2002-07-15

37

Functional requirements and optimisation of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

This report contains a preliminary investigation of site specific design of off-shore wind turbines for a large off-shore wind farm project at Roedsand that is currently being proposed by ELKRAFT/SEAS. The results were found using a design tool for wind turbines that involve numerical optimization and aeroelastic calculations of response. The wind climate was modeled in detail and a cost function was used to estimate costs from manufacture and installation. Cost of energy is higher for off-shore installations. A comparison of an off-shore wind farm site with a typical stand alone on-shore site showed an increase of the annual production of 28% due to the difference in wind climate. Extreme loads and blade fatigue loads were nearly identical, however, fatigue loads on other main components increased significantly. Optimizations were carried out to find the optimum overall off-shore wind turbine design. A wind turbine for the off-shore wind farm should be different compared with a stand-alone on-shore wind turbine. The overall design changed were increased swept area and rated power combined with reduced rotor speed and tower height. Cost was reduced by 12% for the final 5D/14D off-shore wind turbine from 0.306 DKr/kWh to 0.270 DKr/kWh. These figures include capital costs from manufacture and installation but not on-going costs from maintenance. These results make off-shore wind farms more competitive and comparable to the reference on-shore stand-alone wind turbine. A corresponding reduction of cost of energy could not be found for the stand alone on-shore wind turbine. Furthermore the fatigue loads on wind turbines in on-shore wind farms will increase and cost of energy will increase in favor of off-shore wind farms. (au)

Fuglsang, P.; Thomsen, K. [Risoe National Lab., Dept. of Meteorology and Wind Energy (Denmark)

1999-07-01

38

Wind conditions for wind turbine design  

Energy Technology Data Exchange (ETDEWEB)

Delegates from Europe and USA attended the meeting and discussed general aspects of wind conditions for wind turbine design. The subjects and the presented papers covered a very broad range of aspects of wind conditions and related influence on the wind turbine. (EHS)

Maribo Pedersen, B.

1999-04-01

39

Airborne Wind Turbine  

Energy Technology Data Exchange (ETDEWEB)

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

40

Tornado type wind turbines  

Science.gov (United States)

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)

1984-01-01

 
 
 
 
41

Dynamics of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Three principal aspects of the dynamics of wind-turbine behavior are discussed: forced response to deterministic loads, forced response to stochastic loads and stability. In each case, an introduction to the physics of the problem is presented and a means of analysis is described. A simple analytical model is derived to help illustrate some of the analytical techniques commonly employed.

Garrad, A.D.

1983-12-01

42

Dynamics of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Three principal aspects of the dynamics of wind-turbine behaviour are discussed: forced response to deterministic loads, forced response to stochastic loads and stability. In each case, an introduction to the physics of the problem is presented and a means of analysis is described. A simple analytical model is derived to help illustrate some of the analytical techniques commonly employed.

Garrad, A.D.

1983-12-01

43

HWP-300 wind turbine  

Energy Technology Data Exchange (ETDEWEB)

A 300 kW, 22 m diameter wind turbine has been designed and erected (July 1983) on the site of the North of Scotland Hydro-Electric Board at Burgar Hill in Orkney. The machine and its design concepts are described.

Jamieson, P.; Mcleish, D.

1983-12-01

44

Wind turbine spoiler  

Science.gov (United States)

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)

1985-01-01

45

Annoyance rating of wind turbine noise  

International Nuclear Information System (INIS)

[en] This paper proposes a simple criterion for noise limitation of wind turbines: 'The LaA50 from a Wind Farm should not exceeding the LA50 of the wind generated background plus 5dB at any place of potential complaint'. This criterion is then examined and developed in the light of experience to date with turbine noise complaint and procedures. (author)

1992-06-30

46

Annoyance rating of wind turbine noise  

Energy Technology Data Exchange (ETDEWEB)

This paper proposes a simple criterion for noise limitation of wind turbines: 'The La[sub A50] from a Wind Farm should not exceeding the L[sub A50] of the wind generated background plus 5dB at any place of potential complaint'. This criterion is then examined and developed in the light of experience to date with turbine noise complaint and procedures. (author).

Iredale, R.A.

1992-01-01

47

Great expectations: large wind turbines  

International Nuclear Information System (INIS)

This article focuses on wind turbine product development, and traces the background to wind turbines from the first generation 1.5 MW machines in 1995-6, plans for the second generation 3-5 MW class turbines to meet the expected boom in offshore wind projects, to the anticipated installation of a 4.5 MW turbine, and offshore wind projects planned for 2000-2002. The switch by the market leader Vestas to variable speed operation in 2000, the new product development and marketing strategy taken by the German Pro + Pro consultancy in their design of a 1.5 MW variable speed pitch control concept, the possible limiting of the size of turbines due to logistical difficulties, opportunities offered by air ships for large turbines, and the commissioning of offshore wind farms are discussed. Details of some 2-5 MW offshore wind turbine design specifications are tabulated

2001-01-01

48

Great expectations: large wind turbines  

Energy Technology Data Exchange (ETDEWEB)

This article focuses on wind turbine product development, and traces the background to wind turbines from the first generation 1.5 MW machines in 1995-6, plans for the second generation 3-5 MW class turbines to meet the expected boom in offshore wind projects, to the anticipated installation of a 4.5 MW turbine, and offshore wind projects planned for 2000-2002. The switch by the market leader Vestas to variable speed operation in 2000, the new product development and marketing strategy taken by the German Pro + Pro consultancy in their design of a 1.5 MW variable speed pitch control concept, the possible limiting of the size of turbines due to logistical difficulties, opportunities offered by air ships for large turbines, and the commissioning of offshore wind farms are discussed. Details of some 2-5 MW offshore wind turbine design specifications are tabulated.

De Vries, E.

2001-06-01

49

Harmonic Current Predictors for Wind Turbines  

Directory of Open Access Journals (Sweden)

Full Text Available The harmonic impact caused by wind turbines should be carefully investigated before wind turbines are interconnected. However, the harmonic currents of wind turbines are not easily predicted due to the variations of wind speed. If the harmonic current outputs can be predicted accurately, the harmonic impact of wind turbines and wind farms for power grids can be analyzed efficiently. Therefore, this paper analyzes the harmonic current characteristics of wind turbines and investigates the feasibility of developing harmonic current predictors. Field measurement, data sorting, and analysis are conducted for wind turbines. Two harmonic current predictors are proposed based on the measured harmonic data. One is the Auto-Regressive and Moving Average (ARMA)-based harmonic current predictor, which can be used for real-time prediction. The other is the stochastic harmonic current predictor considering the probability density distributions of harmonic currents. It uses the measured harmonic data to establish the probability density distributions of harmonic currents at different wind speeds, and then uses them to implement a long-term harmonic current prediction. Test results use the measured data to validate the forecast ability of these two harmonic current predictors. The ARMA-based predictor obtains poor performance on some harmonic orders due to the stochastic characteristics of harmonic current caused by the variations of wind speed. Relatively, the prediction results of stochastic harmonic current predictor show that the harmonic currents of a wind turbine in long-term operation can be effectively analyzed by the established probability density distributions. Therefore, the proposed stochastic harmonic current predictor is helpful in predicting and analyzing the possible harmonic problems during the operation of wind turbines and wind farms.

Jen-Hao Teng; Rong-Ceng Leou; Chuo-Yean Chang; Shun-Yu Chan

2013-01-01

50

Aeroservoelasticity of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

This thesis deals with the fundamental aeroelastic interaction between structural motion, Pitch action and control for a wind turbine blade. As wind turbines become larger, the interaction between pitch action, blade motion, aerodynamic forces, and control become even more important to understand and address. The main contribution of this thesis is the development of an aeroelastic blade model which on the one hand includes the important effects of steady state blade deformation, gravity and pitch action, and on the other it is transparent, suitable for analytical analysis and parameter studies, and furthermore linear and therefore suitable for control design. The development of the primary aeroelastic blade model is divided into four steps: 1) Nonlinear partial differential equations (PDEs) of structural blade motion are derived together with equations of pitch action and rotor speed; the individual terms in these equations are discussed and given physical interpretations; 2) Steady state blade deformation and induced velocities are computed by combining the PDEs with a steady state aerodynamic model; 3) Aeroelastic modes of motion are computed by combining the linearized PDEs with a linear unsteady aerodynamic model; this model is used to analyze how blade deformation effects the modes of motion; and 4) the linear aeroelastic blade model is derived by a modal expansion of the linearized PDEs combined with a linear unsteady aerodynamic model. The aeroelastic blade model has many similarities to a 2D blade section model, and it can be used instead of this in many applications, giving a transparent connection to a real wind turbine blade. In this work the aeroelastic blade model is used to analyze interaction between pitch action, blade motion and wind speed variations. Furthermore the model is used to develop a state estimator for estimating the wind speed and wind shear, and to suggest a load reducing controller. The state estimator estimates the wind shear very well and the load reducing controller is capable of reducing flapwise blade motion caused by wind shear with 75 % under ideal conditions. So, a new aeroelastic blade model has been derived, which includes important features of large wind turbines, yet simple enough to be suitable for analytical analysis and control design. (au)

Skovmose Kallesoee, B.

2007-12-14

51

Aeroservoelasticity of Wind Turbines  

DEFF Research Database (Denmark)

This thesis deals with the fundamental aeroelastic interaction between structural motion, Pitch action and control for a wind turbine blade. As wind turbines become larger, the interaction between pitch action, blade motion, aerodynamic forces, and control become even more important to understand and address. The main contribution of this thesis is the development of an aeroelastic blade model which on the one hand includes the important effects of steady state blade deformation, gravity and pitch action, and on the other it is transparent, suitable for analytical analysis and parameter studies, and furthermore linear and therefore suitable for control design. The development of the primary aeroelastic blade model is divided into four steps: 1) Nonlinear partial differential equations (PDEs) of structural blade motion are derived together with equations of pitch action and rotor speed; the individual terms in these equations are discussed and given physical interpretations; 2) Steady state blade deformation and induced velocities are computed by combining the PDEs with a steady state aerodynamic model; 3) Aeroelastic modes of motion are computed by combining the linearized PDEs with a linear unsteady aerodynamic model; this model is used to analyze how blade deformation effects the modes of motion; and 4) the linear aeroelastic blade model is derived by a modal expansion of the linearized PDEs combined with a linear unsteady aerodynamic model. The aeroelastic blade model has many similarities to a 2D blade section model, and it can be used instead of this in many applications, giving a transparent connection to a real wind turbine blade. In this work the aeroelastic blade model is used to analyze interaction between pitch action, blade motion and wind speed variations. Furthermore the model is used to develop a state estimator for estimating the wind speed and wind shear, and to suggest a load reducing controller. The state estimator estimates the wind shear very well and the load reducing controller is capable of reducing flapwise blade motion caused by wind shear with 75 % under ideal conditions. So, a new aeroelastic blade model has been derived, which includes important features of large wind turbines, yet simple enough to be suitable for analytical analysis and control design.

KallesØe, Bjarne Skovmose

2007-01-01

52

Pitchcontrol of wind turbines using model free adaptivecontrol based on wind turbine code  

DEFF Research Database (Denmark)

As the wind turbine is a nonlinear high-order system, to achieve good pitch control performance, model free adaptive control (MFAC) approach which doesn't need the mathematical model of the wind turbine is adopted in the pitch control system in this paper. A pseudo gradient vector whose estimation value is only based on I/O data of the wind turbine is identified and then the wind turbine system is replaced by a dynamic linear time-varying model. In order to verify the correctness and robustness of the proposed model free adaptive pitch controller, the wind turbine code FAST which can predict the wind turbine loads and response in high accuracy is used. The results show that the controller produces good dynamic performance, good robustness and adaptability.

Zhang, Yunqian; Chen, Zhe

2011-01-01

53

Ultimate loading of wind turbines  

DEFF Research Database (Denmark)

An extreme loading study has been conducted comprising a general wind climate analysis as well as a wind turbine reliability study. In the wind climate analysis, the distribution of the (horizontal) turbulence standard deviation, conditioned on the meanwind speed, has been approximated by fitting a three parameter Weibull distribution to the measured on-shore and off-shore data for wind speed variations. Specific recommendations on off-shore design turbulence intensities are lacking in the presentIEC-code. Based on the present analysis of the off-shore wind climate on two shallow water sites, a design turbulence intensity for off-shore application is proposed which, in the IEC code framework, is applicable for extreme as well as for fatigue loaddetermination. In order to establish a rational method to analyse wind turbine components with respect to failure in ultimate loading, and in addition to establish partial safety factors for design of such components against this failure mode, structuralreliability methods must be applied. This type of analysis accounts for the variability of the external (wind) loading (as addressed in the analyses of the general wind climate) - and thereby the induced variability in the component stress response - aswell as variability in material resistance. The present study comprises the development of a procedure suitable for dealing with this type of analyses. The main effort has been put on the methodology. Application of the procedure is illustrated byapplication to the event of failure in ultimate loading in flapwise bending in the normal operating condition of a site-specific turbine.

Larsen, Gunner Chr.; Ronold, K.

1999-01-01

54

Small Wind Turbine Technology Assessment  

International Nuclear Information System (INIS)

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 m2) is presented. The study analyzes the collected information on 60 models of wind turbines from 23 manufacturers in the worldwide market. Data from Chinese manufacturers, that have a large participation in the total number of small wind turbines in operation, are not included, due to the unavailability of the technical information. (Author) 15 refs.

1999-01-01

55

Wind turbine acoustic standards  

Science.gov (United States)

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.

1981-05-01

56

Wind powered turbine  

Energy Technology Data Exchange (ETDEWEB)

A wind powered turbine comprises a plurality of vanes tangentially angled about the axis of a drum-like frame. The frame is arranged to rotate about its longitudinal axis and it has a tubular member mounted co-axially with the longitudinal axis within the path swept by the vanes as they rotate. The tubular member constrains the wind to follow an arcuate path between entry and exit points where it reacts with the vanes of the turbine, and may contain an electric generator. The angle of attack on the vanes may be adjusted by a governor or manually, by means of a mechanism comprising two relatively rotatable co-axial rings. (Author)

Farrar, A.P.

1994-08-17

57

Optimum propeller wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

58

Vertical axis wind turbine  

Energy Technology Data Exchange (ETDEWEB)

The wind turbine includes stator blades, rotor blades and a domed, annular shroud with a flared cone. The shroud surmounts the cone and the stator blades extend between the base of the shroud and a lower region of the cone, the shroud having upper and lower openings. The rotor blades are mounted in the shroud for rotation about the central axis of the cone. (author)

Coker, C.M.

1994-02-23

59

Airfoils for wind turbine  

Energy Technology Data Exchange (ETDEWEB)

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

60

Wind Turbine Blade  

DEFF Research Database (Denmark)

The invention relates to a blade for a wind turbine, particularly to a blade that may be produced by an advanced manufacturing process for producing a blade with high quality structural components. Particularly, the structural components, which are preferably manufactured from fibre reinforced plastic material, will have a high level of stretched fibres as well as a far better controlled resin distribution and content and also a low void content.

Jensen, Find MØlholt Technical University of Denmark,

 
 
 
 
61

Make Your Own Wind Turbine  

Science.gov (United States)

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

62

Wind Turbine Providing Grid Support  

DEFF Research Database (Denmark)

A variable speed wind turbine is arranged to provide additional electrical power to counteract non-periodic disturbances in an electrical grid. A controller monitors events indicating a need to increase the electrical output power from the wind turbine to the electrical grid. The controller is arranged to control the wind turbine as follows: after an indicating event has been detected, the wind turbine enters an overproduction period in which the electrical output power is increased, wherein the additional electrical output power is taken from kinetic energy stored in the rotor and without changing the operation of the wind turbine to a more efficient working point.; When the rotational speed of the rotor reaches a minimum value, the wind turbine enters a recovery period to re-accelerate the rotor to the nominal rotational speed while further contributing to the stability of the electrical grid by outputting at least a predetermined minimum electrical power.

Tarnowski, Germán Claudio Technical University of Denmark,

63

Wind turbines in northern climates  

Energy Technology Data Exchange (ETDEWEB)

An overview of wind turbines operating in icing conditions was presented. A computer code to predict ice accretion on horizontal axis wind turbine blades was developed and a possible solution to the problem was determined. The proposed model was based on two aerodynamic codes, one for ice accretion and one for performance prediction. The computer code can be used to predict ice shape and mass on the blades and the corresponding performance degradation. The presence of ice was found to have significant effect on the aerodynamic and aero-elastic behaviour of the blades, reducing power output by more than 20 per cent. Some typical solutions used for de-icing systems include: (1) low temperature steels, (2) low temperature synthetic lubricants and fluids, (3) equipment heaters, (4) black coloured blades, (5) leading edge heaters, (6) a heat source evenly distributed inside the blades to reduce ice adhesion and encourage the cleaning of ice, and (7) a tubular tower. 23 refs., 4 figs.

Patreau, V.; Brahimi, M.T.; Chocran, D.; Paraschivoiu, I. [Ecole Polytechnique de Montreal, Montreal, PQ (Canada)

1998-05-01

64

Value determination of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Cost estimates of wind turbines are based on vague assumptions regarding production costs and learning curves. The report gives - accounting all uncertainties of cost estimates - an approach which determines the breakeven cost of wind turbines. The approach looks at the maximum savings caused by wind turbines in the utility system over some predefined planning horizon. The breakeven value per wind turbine is estimated in terms of the savings realized both in the electric utility all day-production and the expansion planning for conventional units. It is mainly determined by the production savings not by the capital savings.

Dub, W.; Pape, H.

1983-03-01

65

Reliability Analysis of Wind Turbines  

DEFF Research Database (Denmark)

In order to minimise the total expected life-cycle costs of a wind turbine it is important to estimate the reliability level for all components in the wind turbine. This paper deals with reliability analysis for the tower and blades of onshore wind turbines placed in a wind farm. The limit states consideres are in the ultimate limit state (ULS) extreme conditions in the standstill position and extreme conditions during operating. For wind turbines, where the magnitude of the loads is influenced by the control system, the ultimate limit state can occur in both cases. In the fatigue limit state (FLS) the reliability level for a wind turbine placed in a wind farm is considered, and wake effects from neighbouring wind turbines is taken into account. An illustrative example with calculation of the reliability for mudline bending of the tower is considered. In the example the design is determined according to the wind turbine standard IEC 61400-1 "Wind turbines - Design requirements" and different stochastic modelsfor the uncertainties are compared.

Toft, Henrik Stensgaard; SØrensen, John Dalsgaard

2008-01-01

66

Wind turbine-generator  

Energy Technology Data Exchange (ETDEWEB)

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

Kirschbaum, H.S.

1981-09-22

67

Superconducting wind turbine generators  

International Nuclear Information System (INIS)

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.

68

Superconducting wind turbine generators  

DEFF Research Database (Denmark)

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, Asger Bech; Mijatovic, Nenad

2010-01-01

69

Wind tunnel investigation on wind turbine wakes and wind farms  

Science.gov (United States)

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

70

Effects of Icing on Wind Turbine Fatigue Loads  

Energy Technology Data Exchange (ETDEWEB)

The external conditions occurring at cold climate sites will affect wind turbines in different ways. The effects of ice accretion on wind turbines and the influence on the turbine fatigue loads are examined. The amount of icing prior to turbine installation needs to be estimated by using standard measurement data and considering the geometry of the proposed turbine. A procedure to calculate the expected ice accretion on wind turbines out of standard measurement data is explained and the results are discussed. Different parameters to describe the accreted ice on the turbine are examined separately in a fatigue load calculation. The results of the fatigue load calculation are discussed and selected cases are presented.

Frohboese, Peter; Anders, Andreas [Germanischer Lloyd Industrial Services GmbH, Business Segment Wind Energy, Projects Department, Steinhoeft 9, 20459 Hamburg (Germany)

2007-07-15

71

Aerodynamics of wind turbine wakes  

Energy Technology Data Exchange (ETDEWEB)

This report reviews the available literature on the aerodynamics of wind turbines and wind farms. Firstly, two introductory chapters are devoted to the physics of the flow around a wind turbine and the existing engineering models for blade and wake aerodynamics. The focus of this work is however on the numerical modeling of wakes. The difficulties in solving the Navier-Stokes equations are discussed, and the different existing models for the description of the rotor and the wake are mentioned, along with problems associated with the choice of turbulence models and inflow conditions. The purpose of this overview is to include the latest developments in the numerical computation of wind turbine aerodynamics.

Sanderse, B. [ECN Wind Energy, Petten (Netherlands)

2009-04-15

72

Wind turbine facilities noise issues  

Energy Technology Data Exchange (ETDEWEB)

The Ontario Ministry of the Environment (MOE) released a guideline document, in order to help proponents of wind turbine installations with the list of necessary information to be submitted when applying for a certificate of approval under section 9 of the Environmental Protection Act. This article focused on noise guidelines in several MOE publications as well as the issue of complying with wind generated noise limits. It presented an assessment of the appropriateness of the MOE's approach to regulating the noise impacts of wind turbines and provided advice on the science regarding wind turbine noise and on MOE policies and procedures that relate to wind turbine facilities. The report presented a review of a 2006 doctoral dissertation on this issues. It also presented available noise policies and guidelines, relevant scientific literature and the Ministry of Environment's current noise policies as applied to wind turbines. The review of available literature focused on meteorological effects; assessment procedures of wind turbine noise levels; particular characteristics of wind farm noise; and human responses to wind farm noise levels. The report also provided expert opinion based on the above findings. Assessment procedures applied in different jurisdictions have shown that the current MOE process in Ontario is similar to other jurisdictions. Further, the MOE process provides a balanced approach between noise impact and the need for wind farms, based on currently available scientific data. 53 refs., 17 tabs., 28 figs., 6 appendices.

Ramakrishnan, R. [Aiolos Engineering Corp., Toronto, ON (Canada)

2007-12-15

73

Structural reliability of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Structural reliability is presently an area in wind turbine design that draws attention from many different interest groups. Manufactures are looking for reliable methods to design larger and more optimised wind turbines in a safe way. Research institutes and universities are currently involved in activities aiming at developing and refining basic tools within the field. Standardisation bodies, such as IEC, are putting great emphasis on developing rules and regulations in the area. As a result of this common interest, the symposium attracted 15 participants from universities, research institutes, classification bodies and industry giving 11 presentations covering different aspects of the theme of the symposium. At the finalising discussion at the meeting there was a common interest to proceed with information exchange in this area in the future. An Ad Hoc group was sent up in order to formulate a proposal for an annex dealing with structural reliability. The following issues was identified as important for further consideration: I . External conditions (parameter estimation etc.); 2. Partial safety factor calibration; 3. Application of partial safety factors in dynamic simulation; 4. Extrapolation of loads; 5. Assessment of relevant uncertainties; 6. Stochastic modelling of uncertainties; 7. Limit states (fatigue, ultimate); 8. Material strength models; 9. Target reliability level; 10. Case studies and comparisons with good examples; 11. Code format (which partial safety factors etc.); 12. Onshore and offshore. Deliverables: 1. Recommended Practice - code format, - partial safety factors, - methods for adjustment of safety factors; 2. Annual workshops. Proposed title: Structural safety of Wind Turbines. Time frame: 2 (- 3) years. The intention was to be able to present a proposal for a new Annex at the next Executive Committee meeting in Germany April 2002.

NONE

2002-07-01

74

Dual-speed wind turbine generation  

Energy Technology Data Exchange (ETDEWEB)

Induction generator has been used since the early development of utility-scale wind turbine generation. An induction generator is the generator of choice because of its ruggedness and low cost. With an induction generator, the operating speed of the wind turbine is limited to a narrow range (almost constant speed). Dual- speed operation can be accomplished by using an induction generator with two different sets of winding configurations or by using a dual output drive train to drive two induction generators with two different rated speeds. With single-speed operation, the wind turbine operates at different power coefficients (Cp) as the wind speed varies. Operation at maximum Cp can occur only at a single wind speed. However, if the wind speed.varies across a wider range, the operating Cp will vary significantly. Dual-speed operation has the advantage of enabling the wind turbine to operate at near maximum Cp over a wider range of wind speeds. Thus, annual energy production can be increased. The dual-speed mode may generate less energy than a variable-speed mode; nevertheless, it offers an alternative which captures more energy than single-speed operation. In this paper, dual-speed operation of a wind turbine is investigated. Annual energy production is compared between single-speed and dual-speed operation. One type of control algorithm for dual-speed operation is proposed. Some results from a dynamic simulation will be presented to show how the control algorithm works as the wind turbine is exposed to varying wind speeds.

Muljadi, E.; Butterfield, C.P. [National Renewable Energy Lab., Golden, CO (United States); Handman, D. [Flowind Corp., San Rafael, CA (United States)

1996-10-01

75

Potential health impact of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

In response to public health concerns about wind turbines, a study was conducted to review the scientific evidence on the potential health effects of wind turbines. Several research questions were examined, including scientific evidence on the potential health impacts of wind turbines; the relationship between wind turbine noise and health; the relationship between low frequency sound, infrasound and health; assessment of exposure to wind turbines; wind turbine health and safety hazards and Ontario wind turbine setbacks; community consultation prior to wind farm construction and data gaps and research needs. The study showed that although some people living near wind turbines reported symptoms such as dizziness, headaches, and sleep disturbance, the scientific evidence available to date does not demonstrate a direct causal link between wind turbine noise and adverse health effects. The sound level from wind turbines at common residential setbacks is not sufficient to cause hearing impairment or other direct health effects, although some people may find it annoying. 41 refs., 1 appendix.

NONE

2010-05-15

76

Innovation in wind turbine design  

CERN Multimedia

Innovation in Wind Turbine Design addresses the fundamentals of design, the reasons behind design choices, and describes the methodology for evaluating innovative systems and components. Always referencing a state of the art system for comparison, Jamieson discusses the basics of wind turbine theory and design, as well as how to apply existing engineering knowledge to further advance the technology, enabling the reader to gain a thorough understanding of current technology before assessing where it can go in the future. Innovation in Wind Turbine Design is divided into four mai

Jamieson, Peter

2011-01-01

77

Wind turbine supply in Canada  

International Nuclear Information System (INIS)

[en] This study reported on wind turbine supplies to the Canadian market. The report was written to address concerns for Canada's supply outlook in the near future due to the booming wind energy market. Turbine shortages have arisen as a result of continued growth in both European and North American markets. Long lead-times on turbine orders are now increasing the pressure to lock in turbine supply during the initial phases of the development process. Future growth of the wind energy industry will be impacted if turbine supply difficulties continue to contribute to uncertainties in the development process. The report provided an overview of the North American and global wind energy markets, as well as a summary of telephone interviews conducted with turbine suppliers. The implications for the future of turbine supply to the Canadian market were also analyzed. It was concluded that policy-makers should focus on supporting the expansion of manufacturing facilities for small wind turbines and control infrastructure in Canada 7 refs., 3 figs

2007-01-01

78

75 FR 29365 - Job Corps: Final Finding of No Significant Impact (FONSI) for Small Wind Turbine Installation at...  

Science.gov (United States)

...Significant Impact (FONSI) for Small Wind Turbine Installation at the Pine Ridge...Significant Impact (FONSI) for Small Wind Turbine Installation at the Pine Ridge...proposed construction of a small wind turbine at the Pine Ridge Job Corps...

2010-05-25

79

Noise immission from wind turbines  

International Nuclear Information System (INIS)

[en] The project has dealt with practical ways to reduce the influence of background noise caused by wind acting on the measuring microphones. The uncertainty of measured noise emission (source strength) has been investigated. The main activity was a Round Robin Test involving measurements by five laboratories at the same wind turbine. Each laboratory brought its own instrumentation and performed the measurements and analyses according to their interpretation. The tonality of wind turbine noise is an essential component of the noise impact on the environment. In the present project the uncertainty in the newest existing methods for assessing tonality was investigated. The project included noise propagation measurements in different weather conditions around wind turbines situated in different types of terrain. The results were used to validate a noise propagation model developed in the project. Finally, the project also included a study with listeners evaluating recordings of wind turbine noise. The results are intended as guidance for wind turbine manufacturers in identifying the aspects of wind turbine noise most important to annoyance. (author)

1999-01-01

80

Noise immission from wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The project has dealt with practical ways to reduce the influence of background noise caused by wind acting on the measuring microphones. The uncertainty of measured noise emission (source strength) has been investigated. The main activity was a Round Robin Test involving measurements by five laboratories at the same wind turbine. Each laboratory brought its own instrumentation and performed the measurements and analyses according to their interpretation. The tonality of wind turbine noise is an essential component of the noise impact on the environment. In the present project the uncertainty in the newest existing methods for assessing tonality was investigated. The project included noise propagation measurements in different weather conditions around wind turbines situated in different types of terrain. The results were used to validate a noise propagation model developed in the project. Finally, the project alsoincluded a study with listeners evaluating recordings of wind turbine noise. The results are intended as guidance for wind turbine manufacturers in identifying the aspects of wind turbine noise most important to annoyance. (author)

NONE

1999-07-01

 
 
 
 
81

Noise immission from wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The project has dealt with practical ways to reduce the influence of background noise caused by wind acting on the measuring microphones. The uncertainty of measured noise emission (source strength) has been investigated. The main activity was a Round Robin Test involving measurements by five laboratories at the same wind turbine. Each laboratory brought its own instrumentation and performed the measurements and analyses according to their interpretation. The tonality of wind turbine noise is an essential component of the noise impact on the environment. In the present project the uncertainty in the newest existing methods for assessing tonality was investigated. The project included noise propagation measurements in different weather conditions around wind turbines situated in different types of terrain. The results were used to validate a noise propagation model developed in the project. Finally, the project also included a study with listeners evaluating recordings of wind turbine noise. The results are intended as guidance for wind turbine manufacturers in identifying the aspects of wind turbine noise most important to annoyance. (author)

NONE

1999-10-01

82

Probabilistic Design of Wind Turbines  

Directory of Open Access Journals (Sweden)

Full Text Available Probabilistic design of wind turbines requires definition of the structural elements to be included in the probabilistic basis: e.g., blades, tower, foundation; identification of important failure modes; careful stochastic modeling of the uncertain parameters; recommendations for target reliability levels and recommendation for consideration of system aspects. The uncertainties are characterized as aleatoric (physical uncertainty) or epistemic (statistical, measurement and model uncertainties). Methods for uncertainty modeling consistent with methods for estimating the reliability are described. It is described how uncertainties in wind turbine design related to computational models, statistical data from test specimens, results from a few full-scale tests and from prototype wind turbines can be accounted for using the Maximum Likelihood Method and a Bayesian approach. Assessment of the optimal reliability level by cost-benefit optimization is illustrated by an offshore wind turbine example. Uncertainty modeling is illustrated by an example where physical, statistical and model uncertainties are estimated.

John D. Sørensen; Henrik S. Toft

2010-01-01

83

Reliability Assessment Of Wind Turbines  

DEFF Research Database (Denmark)

Reduction of cost of energy for wind turbines are very important in order to make wind energy competitive compared to other energy sources. Therefore the turbine components should be designed to have sufficient reliability but also not be too costly (and safe). This paper presents models for uncertainty modeling and reliability assessment of especially the structural components such as tower, blades, substructure and foundation. But since the function of a wind turbine is highly dependent on many electrical and mechanical components as well as a control system also reliability aspects of these components are discussed and it is described how there reliability influences the reliability of the structural components. Two illustrative examples are presented considering uncertainty modeling, reliability assessment and calibration of partial safety factors for structural wind turbine components exposed to extreme loads and fatigue, respectively.

SØrensen, John Dalsgaard

2013-01-01

84

The aerodynamics of wind turbines  

DEFF Research Database (Denmark)

In the paper we present state-of-the-art of research in wind turbine aerodynamics. We start be giving a brief historical review and a survey over aerodynamic research in wind energy. Next, we focus on some recent research results obtained by our wind energy group at Department of Mechanical Engineering at DTU. In particular, we show some new results on the classical problem of the ideal rotor and present a series of new results from an on-going research project dealing with the modelling and simulation of turbulent flow structures in the wake behind wind turbines.

SØrensen, Jens NØrkær; Mikkelsen, Robert Flemming

2013-01-01

85

Performance testing on wind turbine in natural wind  

Energy Technology Data Exchange (ETDEWEB)

To determine whether a practical wind turbine will operate as expected, performance tests should be carried out in natural wind at the actual site. In field testing, however, the velocity and direction of wind is always fluctuating, making it difficult to select a wind velocity to be used as a basis for calculating the performance. Both the peripheral speed ratio and the torque coefficient, dimensionless values to be used for expressing the turbine performance, should be calculated by using the wind velocity. Thus, results of performance tests in natural wind tend to show large variations and it is often difficult to determine the output characteristics inherent in the wind turbine. In the present study, data are processed by a method that has been proposed by Stacey et al. to be applied to performance testing under outdoor conditions with large fluctuations in wind velocity. A Darrieus-Savonius combination type wind turbine is tested using a battery to apply a load. Results indicate that this data processing method is effective. (11 figs, 2 tabs, 9 refs)

Motohashi, Gen; Takahashi, Hiroshi; Shiono, Osamu; Mitobe, Noriaki; Ono, Tomoaki

1987-06-01

86

Lightning protection of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Lightning damage to wind turbines is a serious problem for Danish power companies, who have experienced some cases with very costly lightning damage and a large number of cases with minor damage. The most costly cases include one catastrophic damage to an entire wind turbine, and several cases of destruction of blades, main bearings, generators and control systems. Over the years there have been several hundreds of cases with minor damage - typically damage and interruptions of the control and communication systems, or the power systems. The Danish power companies anticipate that the lightning threat will be even bigger for the large off-shore wind turbine installations that are currently being planned in Denmark. Furthermore, it is known from the off-shore wind turbines at Vindeby in Denmark that the costs of inspection and particularly repair work must be expected to be much higher off-shore as compared to wind turbines on land. These considerations was the background for a two year project concerned with investigation of lighting damages and with the formulation of a DEFU Recommendation for lightning protection of wind turbines, which was published in January 1999. The project was funded by the Danish power companies Elsam, Eltra, Elkraft and by DEFU. (au)

Soerensen, T.; Brask, M.H. [DEFU (Denmark); Jensen, F.V.; Raben, N. [SEAS (Denmark); Saxov, J. [Nordjyllandsvaerket (Denmark); Nielsen, L. [Vestkraft (Denmark); Soerensen, P.E. [Risoe National Lab. (Denmark)

1999-03-01

87

Wind turbine noise workshop. Proceedings  

Energy Technology Data Exchange (ETDEWEB)

Noise generated by wind turbines is an environmental constraint on the exploitation of wind energy. It is a major consideration when seeking planning consent for the siting of machines due to the high population density in the UK and low levels of background noise in rural areas. There is, therefore, a need to identify the sources and characteristics of noise emitted by wind turbine generators, assess the influences on the propagation of noise through the atmosphere, and provide information to both wind farm developers and planning regulators on noise levels. A one day workshop was organised to provide an opportunity for experts in the field of wind turbine noise to present the current thoughts on the subject and so allow a wide ranging discussion of particular issues of interest. This volume contains the 10 papers presented at the workshop for each of which a separate abstract has been prepared. (author)

Legerton, M. [ed.] [AEA Environment and Energy, Harwell (United Kingdom)

1993-08-01

88

Diffuser augmented wind turbine simulation  

Energy Technology Data Exchange (ETDEWEB)

The effects of enclosing a wind turbine with a simple diffuser on wind energy capture efficiency were investigated. A Reynolds-averaged Navier-Stokes equation solver was used to predict aerodynamic performance. A bare wind turbine rotor was simulated initially for comparison with the experimental data. Simulations were carried out for various diffuser geometry parameters. Computations for various wind speeds were also done for 2 geometries of the diffuser-augmented wind turbine. Results were compared for: mass flow rate; aerodynamic power; power ratio; pressure recovery; overall pressure recovery; diffuser efficiency; and power augmentation. Results indicated that overall diffuser pressure recovery increased linearly with the area ratio. However, its slope decreased with the increase in diffuser length. Trends of pressure recovery and diffuser efficiency as functions of area ratio were similar. It was also observed that the mass flow rate ratio decreased with an increase in the thrust coefficient.11 refs., 17 figs.

Gupta, A.; Henni, A. [Regina Univ., SK (Canada). Dept. of Industrial Systems and Engineering

2006-07-01

89

Footprinting wind turbine fatigue loads  

Energy Technology Data Exchange (ETDEWEB)

The effect of wind farm and complex terrain operation on wind turbine fatigue loading is of great interest but still not easily quantified. Within the EU Non Nuclear Energy R and D Programme the described project 'Measuring Footprints of Wind Turbine Fatigue Loads Using Monitoring Methods' applies a monitoring method on three wind turbines of the same type operating under flat terrain / stand alone, wind farm and complex terrain conditions. Statistics - footprints - of the load quantities are established through on-line rainflow counting of the sampled data. These footprints are evaluated to identify relevant quantities that can serve as shape, intensity and validity parameters. The paper presents the project's objectives and technical approach as well as first measurements and evaluation results.

Soeker, H. [Deutsches Windenergie-Inst., DEWI, Wilhelmshaven (Germany); Morfiadokis, E.; Kossivas, T. [Centre for Renewable Energy Sources, CRES, Pikermi Attiki (Greece); Oestman, A. [Aeronautical Research Inst. of Sweden, Bromma (Sweden)

1999-09-01

90

Rotationally sampled wind and MOD-2 wind turbine response  

Science.gov (United States)

In an effort to learn more about how wind behaves near wind turbines, researchers rotationally sampled winds by attaching sensors to the blades of a MOD-2 wind turbine. This fieldwork demonstrates the feasibility of a blade-mounted measuring technique and provides new data on the winds encountered by a rotating turbine blade.

Connell, J. R.; George, R. L.; Morris, V. R.; Sandborn, V. A.

1985-11-01

91

Asynchronous Generators for use in Gearless Wind Turbines  

DEFF Research Database (Denmark)

In this presentation the squirrel cage induction generator is proposed for a direct-drive wind turbine. The squirrel cage induction generator is proposed for direct drive wind turbines, because of its simple and rugged construction and because it does not require rare earth elements, which are a key element in permanent magnets and might become difficult to source affordably in the future.

Jensen, Bogi Bech Technical University of Denmark,

2011-01-01

92

Air flow behind wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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 results refer to single turbine wakes. The thrust coefficient, C{sub T}, is found to be a better parameter for description of wake characteristics than wind speed, because it implicitly includes the effect of regulation. It is also found that down wind travel time is more convenient to use than down wind distance in this context. The travel time, t{sub 0}, to the end of the near-wake region, i.e. to the point where a single velocity deficit peak first appears, is found to be inversely proportional to the rotational frequency of the turbine and to the turbulence intensity of the ambient air flow and proportional to the ratio of the wake radius and the hub height. For larger travel times, i.e. for the far-wake region, it is found that the centreline relative velocity deficit decreases with the logarithm of the time travelled and is parametrically dependent on t{sub 0} and C{sub T}. The combined wake of two turbines aligned with the wind direction is found to have a lower relative velocity deficit than the wake of a single turbine for the same travel time. This is explained by the inverse relation between t{sub 0} and turbulence intensity, the latter being much higher in the double wake, initially

Magnusson, M.; Smedman, A.-S. [Department of Earth Sciences, Meteorology Uppsala University, Villavaegen 16, S-752 36, Uppsala (Sweden)

1999-03-01

93

Wind turbine airfoil catalogue  

Energy Technology Data Exchange (ETDEWEB)

The aim of this work is two-sided. Firstly, experimental results obtained for numerous sets of airfoil measurements (mainly intended for wind turbine applications) are collected and compared with computational results from the 2D Navier-Stokes solver EllipSys2D, as well as results from the panel method code XFOIL. Secondly, we are interested in validating the code EllipSys2D and finding out for which air-foils it does not perform well compared to the experiments, as well as why, when it does so. The airfoils are classified according to the agreement between the numerical results and experimental data. A study correlating the available data and this classification is performed. It is found that transition modelling is to a large extent responsible for the poor quality of the computational results for most of the considered airfoils. The transition model mechanism that leads to these discrepancies is identified. Some advices are given for elaborating future airfoil design processes that would involve the numerical code EllipSys2D in particular, and transition modelling in general. (au)

Bertagnolio, F.; Soerensen, N.; Johansen, J.; Fuglsang, P.

2001-08-01

94

Wind turbine airfoil catalogue  

DEFF Research Database (Denmark)

The aim of this work is two-sided. Firstly, experimental results obtained for numerous sets of airfoil measurements (mainly intended for wind turbine applications) are collected and compared with computational results from the 2D Navier-Stokes solverEllipSys2D, as well as results from the panel method code XFOIL. Secondly, we are interested in validating the code EllipSys2D and finding out for which airfoils it does not perform well compared to the experiments, as well as why, when it does so. Theairfoils are classified according to the agreement between the numerical results and experimental data. A study correlating the available data and this classification is performed. It is found that transition modelling is to a large extent responsible forthe poor quality of the computational results for most of the considered airfoils. The transition model mechanism that leads to these discrepancies is identified. Some advices are given for elaborating future airfoil design processes that would involvethe numerical code EllipSys2D in particular, and transition modelling in general.

Bertagnolio, F.; SØrensen, Niels N.

2001-01-01

95

Wind turbine noise workshop. Proceedings.  

Science.gov (United States)

Noise generated by wind turbines is an environmental constraint on the exploitation of wind energy. It is a major consideration when seeking planning consent for the siting of machines due to the high population density in the UK and low levels of backgro...

M. Legerton

1993-01-01

96

Extreme Response for Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The characteristic load on wind turbines during operation are among others dependent on the mean wind speed, the turbulence intensity and type and settings of the control system. The characteristic load during operation is normally estimated by statistical extrapolation of a limited number of simula...

Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

97

Load Extrapolation During Operation for Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the recent years load extrapolation for wind turbines has been widely considered in the wind turbine industry. Loads on wind turbines during operations are normally dependent on the mean wind speed, the turbulence intensity and the type and settings of the control system. All these parameters mus...

Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

98

Foundations for offshore wind turbines.  

UK PubMed Central (United Kingdom)

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.

Byrne BW; Houlsby GT

2003-12-01

99

TV Interference from Wind Turbines  

UK PubMed Central (United Kingdom)

Wind turbines may be a source of disturbancein the radiation fields of TV broadcast transmitters. Thesituation is particularly serious when the direct path fromthe transmitter to the receiver antenna is obstructed whileboth transmitter and receiver antennas have a unblockedpath to the wind turbine. Starting from an analysis of thedi#racted field by the pylon we proceed to implement a simplerule derived from ITU Recommendation 805 to definea minimum clearance distance from an isolated wind turbineand a TV transmitter antenna. Measurements using ascaled model confirm the existence of the floor level in thescatter model used in ITU Recommendation BT.805.I.

Carlos Salema; Carlos Fern; Luca Fauro

100

Noise from offshore wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Noise assessment of wind turbines through calculations is based on sound power levels measured according to e.g. IEC 61400-11. With larger wind turbines and distances some of the calculation models give erroneous results. Noise propagation over water is different from propagation over land. For that reason it is important be able to make valid noise assessments for offshore wind farms. A suggestion for an offshore measurement method is described and a survey of models for noise propagation offshore has been made. (au)

Soendergaard, B.; Plovsing, B.

2005-07-01

 
 
 
 
101

Results of a wind turbine FDI competition  

DEFF Research Database (Denmark)

In this paper some newly published methods for fault detection and isolation developed for a wind turbine benchmark model are tested, compared and evaluated. These methods have been presented as a part of an international competition. The tested methods cover different types of fault detection and isolation methods, which include support vector machines, observer based methods, and auto generated methods. All of these methods show interesting potentials for usage in the wind turbine application, but all with different strong and weak sides in relation to the requirements specified in the proposed benchmark model.

Odgaard, Peter Fogh; Stoustrup, Jakob

2012-01-01

102

Fault tolerant control of wind turbines using unknown input observers  

DEFF Research Database (Denmark)

This paper presents a scheme for accommodating faults in the rotor and generator speed sensors in a wind turbine. These measured values are important both for the wind turbine controller as well as the supervisory control of the wind turbine. The scheme is based on unknown input observers, which are also used to detect and isolate these faults. The scheme is tested on a known benchmark for FDI and FTC of wind turbines. Tests on this benchmark model show a clear potential of the proposed scheme.

Odgaard, Peter Fogh; Stoustrup, Jakob

2012-01-01

103

FloWind advanced wind turbines research  

Energy Technology Data Exchange (ETDEWEB)

A review is presented of FloWind Corporation`s advanced wind turbine technology. The horizontal axis FloWind AWT-26 can produce power for 5.3 cents/kWh, utilizing advanced airfoils and a downwind free yaw system. It weighs substantially less than its competitors, enabling it to be mounted on very tall towers. FloWind has been selected to deliver 25 MW through a consortium of Washington Public Utility District`s Conservation and Renewable Energy System. The extended height-to-diameter (EHT) vertical axis wind turbine (VAWT) allows production of more power on the same area of land, takes advantage of wind shear, and maximizes the swept area while minimizing wake effects. Pultruded, fiberglass composite blades can be pulled from the die and erected on site, saving labor and materials costs. Two-hundred and three 17 m VAWT produce a total wind farm swept area of 106,000 m{sup 2}, compared to only 46,081 m{sup 2} for the same number of 17 m horizontal axis turbines. 1 tab.

Davies, A.K. [FloWind Corp., San Rafael, CA (United States)

1993-12-31

104

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-03-01

105

Wind turbines fundamentals, technologies, application, economics  

CERN Multimedia

Addresses those professionally involved in research, development, manufacture, and operation of wind turbines, this second edition provides a cross-disciplinary overview of modern wind turbine technology, and an orientation in the associated technical, economic, and environmental fields.

Hau, Erich

2005-01-01

106

Statistical variation of wind turbine fatigue loads.  

Science.gov (United States)

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

107

Wind Turbine Control: Robust Model Based Approach  

DEFF Research Database (Denmark)

In the 1970s the oil price crisis encouraged investigation of non-petroleum energy sources of which wind energy was the most promising one. Lately global warming concerns have even intensified the demand for green and sustainable energy resources and opened up several lines of research in this area. Wind turbines are the most common wind energy conversion systems and are hoped to be able to compete economically with fossil fuel power plants in near future. However this demands better technology to reduce the price of electricity production. Control can play an essential part in this context. This is because, on the one hand, control methods can decrease the cost of energy by keeping the turbine close to its maximum efficiency. On the other hand, they can reduce structural fatigue and therefore increase the lifetime of the wind turbine. The power produced by a wind turbine is proportional to the square of its rotor radius, therefore it seems reasonable to increase the size of the wind turbine in order to capture more power. However as the size increases, the mass of the blades increases by cube of the rotor size. This means in order to keep structural feasibility and mass of the whole structure reasonable, the ratio of mass to size should be reduced. This trend results in more flexible structures. Control of the flexible structure of a wind turbine in a wind field with stochastic nature is very challenging. In this thesis we are examining a number of robust model based methods for wind turbine control. Firstly we examine potentials of -synthesis methods and use -tools to analyze robustness of the resulting controllers both in terms of robust stability and robust performance. Afterwards we employ model predictive control (MPC) and show that the way MPC solves control problems suits wind turbine control problems very well, especially when we have preview measurements of wind speed using LIDARs. For the control problem with LIDAR measurements we have proposed a new MPC approach which gives better results than linear MPC while it has almost the same computational complexity. We have also tackled wind turbine control using robust MPC. In general, robust MPC problems are very computationally demanding, however we have shown that with some approximations the resulting robust MPC problem can be specialized with reduced computational complexity. After a short introduction on wind energy and wind turbines in chapter 1, we briefly explain wind turbine modeling in chapter 2. Introductions to different control design methods are given in chapter 3. The goal of this chapter is to show how different control methods are chosen. The next eight chapters comprise the body of the thesis and are scientific papers that are published or going to be published. Control methods which were briefly introduced in chapter 3 are explained in these chapters in details.

Mirzaei, Mahmood

2012-01-01

108

Vertical axis wind turbine airfoil  

Science.gov (United States)

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

109

Wind turbine noise source characterization  

Energy Technology Data Exchange (ETDEWEB)

Wind turbine noise is a function of many parameters. Aerodynamics noise is a direct function of the rotor characteristics and wind speed, which can change rapidly with time. Mechanical noise is primarily a function of electrical power output, but the radiation of such noise is highly modified by vibration behaviour within the turbine. An experiment has been performed to isolate the behaviour of the major WTG noise sources with respect to electrical power output and wind speed. Twelve ground based microphones equispaced around the turbine gave detailed noise directionality information. Additional instrumentation was added to allow the separation of aerodynamic and mechanical noise components. Noise was found to be very well correlated to electrical power output. (author)

Lowson, J.V. [Flow Solutions Ltd., Bristol (United Kingdom); Bullmore, A.J. [Hoare Lea and Partners, Bristol (United Kingdom)

1997-06-01

110

Wind turbine noise source characterization  

International Nuclear Information System (INIS)

[en] Wind turbine noise is a function of many parameters. Aerodynamics noise is a direct function of the rotor characteristics and wind speed, which can change rapidly with time. Mechanical noise is primarily a function of electrical power output, but the radiation of such noise is highly modified by vibration behaviour within the turbine. An experiment has been performed to isolate the behaviour of the major WTG noise sources with respect to electrical power output and wind speed. Twelve ground based microphones equispaced around the turbine gave detailed noise directionality information. Additional instrumentation was added to allow the separation of aerodynamic and mechanical noise components. Noise was found to be very well correlated to electrical power output. (author)

1997-01-01

111

A novel floating offshore wind turbine concept  

DEFF Research Database (Denmark)

This paper will present a novel concept of a floating offshore wind turbine. The new concept is intended for vertical-axis wind turbine technology. The main purpose is to increase simplicity and to reduce total costs of an installed offshore wind farm. The concept is intended for deep water and large size turbines.

Vita, Luca; Schmidt Paulsen, Uwe

2009-01-01

112

RBI Optimization of Offshore Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Wind turbines for electricity production have increased significantly the last years both in production capability and size. This development is expected to continue also in the coming years. Offshore wind turbines with an electricity production of 5-10 MW are planned. Typically, the wind turbine su...

Ramírez, José G. Rangel; Sørensen, John Dalsgaard

113

Estimation of electric power production on small wind turbines  

Energy Technology Data Exchange (ETDEWEB)

In planning an installation of small wind turbines, it is necessary to evaluate the inaccuracies in the estimation of electric power production based on the Weibull distribution. However, the authors establish a more accurate method of power output estimation. This report presents a proposal for a more accurate way of predicting the electric power production by small wind turbines. As the results, the estimated values of small wind turbines designed for the moderate wind speed range, agreed well with the observed values. On the other hand, in the case of a small wind turbines designed for higher output in higher wind speed range, the estimated values of electric power production were to large compared to the observed values. However, the estimated values of the latter cases could be made closer to the observed values by limiting the operating wind speed range to two or three times of the average wind speed.

Matsuzawa, Keisuke; Ushiyama, Izumi; Nagai, Hiroshi

1999-07-01

114

Economics of Small Wind Turbines  

Science.gov (United States)

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

115

New guidelines for wind turbine gearboxes  

Energy Technology Data Exchange (ETDEWEB)

The American Gear Manufacturers Association in cooperation with the American Wind Energy Association will soon be publishing AGMA/AWEA 921-A97 {open_quotes}Recommended Practices for Design and Specification of Gearboxes for Wind Turbine Generator Systems.{close_quotes} Much has been learned about the unique operation and loading of gearboxes in wind turbine applications since the burgeoning of the modern wind turbine industry in the early 1980`s. AGMA/AWEA 921-A97 documents this experience in a manner that provides valuable information to assist gear manufacturers and wind turbine designers, operators, and manufacturers in developing reliable wind turbine gearboxes. The document provides information on procurement specification development, wind turbine architecture, environmental considerations, and gearbox load determination, as well as the design, manufacturing, quality assurance, lubrication, operation and maintenance of wind turbine gearboxes. This paper presents the salient parts of the practices recommended in AGMA/AWEA 921-A97.

McNiff, B. [McNiff Light Industry, Blue Hill, ME (United States); Errichello, R. [GEARTECH, Townsend, MT (United States)

1997-12-31

116

Integrated installation for offshore wind turbines  

Energy Technology Data Exchange (ETDEWEB)

A project to investigate the feasibility of integrating the offshore installation of foundation, turbine and tower for offshore wind turbines into one operation is described. Three separate objectives are listed. They are: (1) Telescopic tower study - reversible process incorporating lift and lock mechanisms; (2) Transportation study - technical and economic feasibility of transporting and installing a wind turbine unit via a standard barge with minimal conversion and (3) Self-burial system study - to demonstrate the feasibility of self burial of a slab foundation via controlled jetting beneath the slab. The background to the study and the proposed concepts are discussed. The work carried out to date and the costs are reported together with the findings. Recommendations for future work are listed. The work was carried out by Corus UK Ltd and is managed by Future Energy Solutions for the DTI.

Way, J.; Bowerman, H.

2003-07-01

117

Sound wave contours around wind turbine arrays  

International Nuclear Information System (INIS)

[en] Noise pollution is an important factor in selecting suitable sites for wind turbines in order to realize 1000 MW of wind power as planned by the Dutch government for the year 2000. Therefore an accurate assessment of wind turbine noise is important. The amount of noise pollution from a wind turbine depends on the wind conditions. An existing standard method to assess wind turbine noise is supplemented and adjusted. In the first part of the investigation the method was developed and applied for a solitary sound source. In the second part attention is paid to the use of the method for wind turbine arrays. It appears that the adjusted method results in a shift of the contours of the permitted noise level. In general the contours are 15-25% closer to the wind farm, which means that the minimal permitted distance between houses and wind turbine arrays can be reduced. 14 figs., 1 tab., 4 appendices, 7 refs

118

Wind Turbine Siting: Wildlife Concerns  

Science.gov (United States)

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

119

The HWP-300 wind turbine  

Energy Technology Data Exchange (ETDEWEB)

A 300 kW, 22 m diameter wind turbine has been designed by James Howden and Company, and erected (July 1983) on the site of the North of Scotland Hydro-Electric Board at Burgar Hill in Orkney. The machine and its design concepts are described.

Jamieson, P.; McLeish, D.

1983-12-01

120

Fatigue loads for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

A brief article discusses the types of loads in wind turbines including transient loads, steady operational loads and extreme loads and concentrates on the prediction of the loads. The level of confidence with which the loads may be predicted is described and the interface between the load prediction and the fatigue life prediction discussed. (UK).

Garrad, A.D. (Flight Refuelling Ltd., Wimborne (UK))

1989-01-01

 
 
 
 
121

Mechanical noise from wind turbines  

International Nuclear Information System (INIS)

[en] Community annoyance due to noise from wind turbines is often the result of noise character rather than level. Although the overall contributions from each of the two main classes of noise source, namely aerodynamic and mechanical, are often of a similar order for an untreated turbine, it is usually the mechanical sources which provide the dominant noise characteristics that may lead to annoyance. In this paper, the sources of mechanical noise are identified primarily with reference to horizontal axis wind turbines and then attention is concentrated on the rotor-shaft step-up gearbox, which is normally the top-ranking source. The major gearbox noise mechanisms and transmission paths are discussed and reference made to Noise Specifications and procedures applicable to the gearbox prior to its installation. The reduction of machinery noise is reviewed both at source and by treatment of transmission paths. (author)

1992-06-30

122

Near-wake behaviour of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

For studies of the flow downstream wind turbines, the initial state of the flow is of importance. In this study the flow generated by a wind turbine has been calculated. The purpose is to study how a logarithmic wind profile and yaw, modifies the initial state. For validation of the model, measurements from the Alsvik wind farm are used

Magnusson, M. [Department of Earth Sciences, Meteorology, Uppsala University, Villavaegen 16, S-752 36 Uppsala (Sweden)

1999-03-01

123

Fault tolerant wind speed estimator used in wind turbine controllers  

DEFF Research Database (Denmark)

Advanced control schemes can be used to optimize energy production and cost of energy in modern wind turbines. These control schemes most often rely on wind speed estimations. These designs of wind speed estimators are, however, not designed to be fault tolerant towards faults in the used sensors. In this paper a fault tolerant wind speed estimator is designed based on a set of unknown input observers, each designed to the different sets of non-faulty sensors. Faults in the rotor, generator and wind speed sensors are considered. The designed wind speed estimator is passive tolerant towards faults in the wind speed sensors, and faults in the generator and rotor speed sensors are accommodated by an active fault tolerant observer scheme in which the faults are detected and identified, and the observer corresponding to the non-faulty sensors are used. The potential of the scheme is shown by applying the proposed wind speed estimator to a simulation model of a wind turbine. Notice that since the faults are accommodated in the observer scheme the actual controller do not need to be adjusted or reconfigured to accommodate the sensor faults.

Odgaard, Peter Fogh; Stoustrup, Jakob

2012-01-01

124

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

Energy Technology Data Exchange (ETDEWEB)

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

2004-11-01

125

Dynamic simulation of dual-speed wind turbine generation  

Energy Technology Data Exchange (ETDEWEB)

Induction generators have been used since the early development of utility-scale wind turbine generation. An induction generator is the generator of choice because of its ruggedness, and low cost. With an induction generator, the operating speed of the wind turbine is limited to a narrow range (almost constant speed). Dual- speed operation can be accomplished by using an induction generator with two different sets of winding configurations or by using two induction generators with two different rated speeds. With single- speed operation, the wind turbine operates at different power coefficients (Cp) as the wind speed varies. The operation at maximum Cp can occur only at a single wind speed. However, if the wind speed varies across a wider range, the operating Cp will vary significantly. Dual-speed operation has the advantage of enabling the wind turbine to operate at near maximum Cp over a wider range of wind-speeds. Thus, annual energy production can be increased. The dual-speed mode may generate less energy than a variable-speed mode; nevertheless, it offers an alternative to capture more energy than single-speed operation. In this paper, dual-speed operation of a wind turbine will be investigated. One type of control algorithm for dual- speed operation is proposed. Results from a dynamic simulation will be presented to show how the control algorithm works and how power, current and torque of the system vary as the wind turbine is exposed to varying wind speeds.

Muljadi, E.; Butterfield, C.P.

1996-10-01

126

Effects of Icing on Wind Turbine Fatigue Loads  

International Nuclear Information System (INIS)

[en] The external conditions occurring at cold climate sites will affect wind turbines in different ways. The effects of ice accretion on wind turbines and the influence on the turbine fatigue loads are examined. The amount of icing prior to turbine installation needs to be estimated by using standard measurement data and considering the geometry of the proposed turbine. A procedure to calculate the expected ice accretion on wind turbines out of standard measurement data is explained and the results are discussed. Different parameters to describe the accreted ice on the turbine are examined separately in a fatigue load calculation. The results of the fatigue load calculation are discussed and selected cases are presented

2007-01-01

127

RBI Optimization of Offshore Wind Turbines  

DEFF Research Database (Denmark)

Wind turbines for electricity production have increased significantly the last years both in production capability and size. This development is expected to continue also in the coming years. Offshore wind turbines with an electricity production of 5-10 MW are planned. Typically, the wind turbine support structure is a steel structure consisting of a tower and a monopile, tripod or jacket type foundation. This paper considers aspects of inspection and maintenance planning of fatigue prone details in jacket and tripod type of wind turbine support structures. Based on risk-based inspection planning methods for oil & gas installations, a framework for optimal inspection and maintenance planning of offshore wind turbines is presented. Special aspects for offshore wind turbines considered are the fatigue loading characteristics where usually the wind loading are dominating the wave loading, wake effects in wind farms and also the reliability level which is typically significantly lower than for oil & gas installations. An illustrative example is presented.

Ramírez, José G. Rangel; SØrensen, John Dalsgaard

2009-01-01

128

Dynamic Models for Wind Turbines and Wind Power Plants  

Energy Technology Data Exchange (ETDEWEB)

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

Singh, M.; Santoso, S.

2011-10-01

129

Market for wind turbines in italy  

International Nuclear Information System (INIS)

Wind power utilization in Italy has not been very popular until the privatization of the ENEL and introduction of subsidies for private electricity producers. The greatest interest is concentrated around large wind turbines. Therefore the Danish manufacturers with know-how within large wind turbines can establish themselves on the Italian market. Cooperation with one of the four local wind turbine manufacturers is advisable. (EG).

1997-01-01

130

Potential health impact of wind turbines  

International Nuclear Information System (INIS)

[en] In response to public health concerns about wind turbines, a study was conducted to review the scientific evidence on the potential health effects of wind turbines. Several research questions were examined, including scientific evidence on the potential health impacts of wind turbines; the relationship between wind turbine noise and health; the relationship between low frequency sound, infrasound and health; assessment of exposure to wind turbines; wind turbine health and safety hazards and Ontario wind turbine setbacks; community consultation prior to wind farm construction and data gaps and research needs. The study showed that although some people living near wind turbines reported symptoms such as dizziness, headaches, and sleep disturbance, the scientific evidence available to date does not demonstrate a direct causal link between wind turbine noise and adverse health effects. The sound level from wind turbines at common residential setbacks is not sufficient to cause hearing impairment or other direct health effects, although some people may find it annoying. 41 refs., 1 appendix.

2010-01-01

131

Vertical axis wind turbines: a survey and bibliography  

Energy Technology Data Exchange (ETDEWEB)

The stimulus for the development of modern, big wind turbines has been the world-wide oil crisis during the seventies. Although the horizontal axis wind turbines (HAWT) was the most popular type of wind turbine the Darrieus vertical axis wind turbine (VAWT) has been recognized as a machine with competitive economic potential. The state of the art of the VAWT is reviewed. The wind turbine carrying the name of Darrieus was first proposed by the French inventor in 1925. His original patent covered a range of vertical-axis configurations but the term 'Darrieus' is now generally associated with the curved-blade geometry. In 1966 two researchers at the Canadian NRC again raised the idea of both the straight and curved-blade versions of the Darrieus VAWT.

Abramovich, H.

1987-01-01

132

On the Fatigue Analysis of Wind Turbines  

UK PubMed Central (United Kingdom)

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 components has matured to the point thatthe prediction of service lifetime is becoming an essential part of the design process. In thisreview paper, I summarize the technology and describe the "best practices" for the fatigueanalysis of a wind turbine component. The paper focuses on U.S. technology, but cites Europeanreferences that provide important insights into the fatigue analysis of wind turbines.ivAcknowledgmentsIn this article, I have drawn upon the work of many researchers. I wish to express myappreciation to them and to the many ot...

Herbert J. Sutherland

133

On the Fatigue Analysis of Wind Turbines  

Energy Technology Data Exchange (ETDEWEB)

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

Sutherland, Herbert J.

1999-06-01

134

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

Energy Technology Data Exchange (ETDEWEB)

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

Huskey, A.

2011-11-01

135

Optimal size of wind turbine transformer  

Energy Technology Data Exchange (ETDEWEB)

During the past decade considerable efforts have been put into the efficiency of wind turbines. Almost every component in wind turbines has been the object of optimization. Still, when it comes to grid connection the transformer is very often oversized. In this paper the cost price of transformers is compared with the cost of transformer losses. The transformer losses are calculated from the wind probability curve and the power curve of the wind turbine. The temperature and thereby the lifetime of the transformer are calculated based on the IEC 354. The results show that an optimal transformer kVa is 20% lower than the rated power of the wind turbine.

Larsson, Aake [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electric Power Engineering

1999-09-01

136

Probabilistic fatigue methodology and wind turbine reliability  

Energy Technology Data Exchange (ETDEWEB)

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

Lange, C.H. [Stanford Univ., CA (United States)

1996-05-01

137

Wind turbine power tracking using an improved multimodel quadratic approach.  

UK PubMed Central (United Kingdom)

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.

Khezami N; Benhadj Braiek N; Guillaud X

2010-07-01

138

Wind turbine power tracking using an improved multimodel quadratic approach.  

Science.gov (United States)

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

139

Standards for measurements and testing of wind turbine power quality  

Energy Technology Data Exchange (ETDEWEB)

The present paper describes the work done in power quality sub-task of the project `European Wind Turbine Testing Procedure Developments` funded by the EU SMT program. The objective of the power quality sub-task has been to make analyses and new recommendation(s) for the standardisation of measurement and verification of wind turbine power quality. The work has been organised in three major activities. The first activity has been to propose measurement procedures and to verify existing and new measurement procedures. This activity has also involved a comparison of the measurements and data processing of the participating partners. The second activity has been to investigate the influence of terrain, grid properties and wind farm summation on the power quality of wind turbines with constant rotor speed. The third activity has been to investigate the influence of terrain, grid properties and wind farm summation on the power quality of wind turbines with variable rotor speed. (au)

Soerensen, P. [Risoe National Lab., Roskilde (Denmark); Gerdes, G.; Klosse, R.; Santjer, F. [DEWI, Wilhelmshaven (Germany); Robertson, N.; Davy, W. [NEL, Glasgow (United Kingdom); Koulouvari, M.; Morfiadakis, E. [CRES, Pikermi (Greece); Larsson, Aa. [Chalmers Univ. of Technology, Goeteborg (Sweden)

1999-03-01

140

Wind Turbine Manufacturing Process Monitoring  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-04-26

 
 
 
 
141

Cost optimization of wind turbines for large-scale offshore wind farms  

Energy Technology Data Exchange (ETDEWEB)

This report contains a preliminary investigation of site specific design of off-shore wind turbines for a large off-shore wind farm project at Roedsand that is currently being proposed by ELKRAFT/SEAS. The results were found using a design tool for wind turbines that involve numerical optimization and aeroelastic calculations of response. The wind climate was modeled in detail and a cost function was used to estimate costs from manufacture and installation. Cost of energy is higher for off-shore installations. A comparison of an off-shore wind farm site with a typical stand alone on-shore site showed an increase of the annual production of 28% due to the difference in wind climate. Extreme loads and blade fatigue loads were nearly identical, however,fatigue loads on other main components increased significantly. Optimizations were carried out to find the optimum overall off-shore wind turbine design. A wind turbine for the off-shore wind farm should be different compared with a stand-alone on-shore wind turbine. The overall design changed were increased swept area and rated power combined with reduced rotor speed and tower height. Cost was reduced by 12% for the final 5D/14D off-shore wind turbine from 0.306 DKr/kWh to 0.270 DKr/kWh. These figures include capital costs from manufacture and installation but not on-going costs from maintenance. These results make off-shore wind farms more competitive and comparable to the reference on-shore stand-alone wind turbine. A corresponding reduction of cost of energy could not be found for the stand alone on-shore wind turbine. Furthermore the fatigue loads on wind turbines in on-shore wind farms will increase and cost of energy will increase in favor of off-shore wind farms. (au) EFP-95; EU-JOULE-3; 21 tabs., 7 ills., 8 refs.

Fuglsang, P.; Thomsen, K.

1998-02-01

142

Wind turbines brace themselves for change  

Energy Technology Data Exchange (ETDEWEB)

The British Wind Energy Association held its annual meeting in Oxford during March 1985, with speakers reviewing the wind power situation. While wind turbines must now compete on an equal footing with other power sources, they have now developed to a point where they are competitive. Latest turbine developments in Belgium, Canada, Denmark, Romania, Sweden, and the UK, are summarized briefly here.

Conway, A.

1985-05-01

143

Acoustic noise measurements on wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The acoustic noise emitted by wind turbines can be a serious obstacle for the realisation of wind energy projects. This is especially the case in countries with a high population density like the Netherlands. For this reason the acoustic noise emission of wind turbines is an important item for the manufacturers of turbines (who want to minimize the emission) and for the licensing authorities (who want to predict the noise immission of the turbine at a certain distance). The noise emission can be characterised by performing acoustic noise measurements in the vicinity of the wind turbine according to recommended practices. At the moment three documents are available describing recommended practices for the measurement of wind turbine noise. These documents are compared. ECN has performed acoustic noise measurements on wind turbines since 1982. Due to the increased importance of wind turbine noise the measurement procedure and data treatment has been modified substantially. The new procedure is described, together with some examples of measurement results. A list of measured acoustic source power data of various wind turbines has been obtained from measurements by ECN and from the open literature. Using these data an empirical relation has been calculated between the source power and the rotor diameter of the wind turbines. The source power data and the empirical relation are given. 6 figs., 36 refs., 1 tab.

Van der Borg, N.J.C.M.; Stam, W.J.

1989-06-01

144

Wind turbine. Windmotor  

Energy Technology Data Exchange (ETDEWEB)

The invention concerns a wind rotor similar to the Savonius rotor, with two pairs of vertical semicircular vanes at an angle of 90/sup 0/ to each other and a vertical axis with a cast gripper, rotating head and dynamo housing with 1 or 2 dynamos. The invention is characterised by the fact that the above parts are built into a system of struts, instead of the well-known horizontal plates. The system of struts consists of two double struts and a cross of double struts with short simple struts. The double struts are provided with perforated flat steel connections in the centre and at the ends, where the projecting ends of the vertical struts are worked in. The wind rotor is connected with the mast by the axis and rotating head so that it can rotate. The dynamo is operated directly. The gripper has a crown wheel, by which a second dynamo can be operated.

Weiss, G.

1981-10-22

145

Development of Superconducting Wind Turbine Generators  

DEFF Research Database (Denmark)

In this paper the commercial activities in the field of superconducting machines, particularly superconducting wind turbine generators, are reviewed and presented. Superconducting generators have the potential to provide a compact and light weight drive train at high torques and slow rotational speeds, because high magnetic fields can be produced by coils with very little loss. Three different superconducting wind turbine generator topologies have been proposed by three different companies. One is based on low temperature superconductors (LTS); one is based on high temperature superconductors (HTS); and one is a fully superconducting generator based on MgB2. It is concluded that there is large commercial interest in superconducting machines, with an increasing patenting activity. Such generators are however not without their challenges. The superconductors have to be cooled down to somewhere between 4K and 50K, depending on what type of superconductor is employed, which poses a significant challenge both from a construction and operation point of view. The high temperature superconductors can facilitate a higher operation temperature and simplified cooling, but the current price and production volumes prohibit a large scale impact on the wind sector. The low temperature superconductors are readily available, but will need more sophisticated cooling. Eventually the CoE from superconducting wind turbines, with particular emphasis on reliability, will determine if they become feasible or not and for such investigations large-scale demonstrations will be needed.

Jensen, Bogi Bech; Mijatovic, Nenad

2012-01-01

146

Wind turbine aerodynamics research needs assessment  

Science.gov (United States)

A prioritized list is developed for wind turbine aerodynamic research needs and opportunities which could be used by the Department of Energy program management team in detailing the DOE Five-Year Wind Turbine Research Plan. The focus of the Assessment was the basic science of aerodynamics as applied to wind turbines, including all relevant phenomena, such as turbulence, dynamic stall, three-dimensional effects, viscosity, wake geometry, and others which influence aerodynamic understanding and design. The study was restricted to wind turbines that provide electrical energy compatible with the utility grid, and included both horizontal axis wind turbines (HAWT) and vertical axis wind turbines (VAWT). Also, no economic constraints were imposed on the design concepts or recommendations since the focus of the investigation was purely scientific.

Stoddard, F. S.; Porter, B. K.

1986-01-01

147

Utility Scale Wind turbine Demonstration Project  

Energy Technology Data Exchange (ETDEWEB)

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

Terry Fredericks

2006-03-31

148

On System Identification of Wind Turbines  

DEFF Research Database (Denmark)

Recently several methods have been proposed for the system identification of wind turbines which can be considered as a linear time-varying system due to the operating conditions. For the identification of linear wind turbine models, either black-box or grey-box identification can be used. In the case of black-box identification no "physical" model structure is assumed and a large number of parameters have to be defined by the identification techniques. For the identified black-box models, it is difficult to perform model analysis since the internal states are not known to the user. The operational model analysis (OMA) methodology can provide accurate estimates of the natural frequencies, damping ratios and mode shapes of the systems as long as the measurements have a low noise to signal ratio. However, in order to take information about the wind turbine into account a grey-box identification method can be used. This paper reviews proposed system identification methods and the durability and the limitations of the different methods are outlined.

Kirkegaard, Poul Henning; Perisic, Nevena

149

Market experiences with small wind turbines  

International Nuclear Information System (INIS)

An overview is given of the marketing experiences of Lagerwey Windturbines with the exploitation of small wind turbines. Attention is paid to the market mechanisms which effect the sale and implementation of small wind turbines: payback of surplus power, provincial and regional subsidies, grid connection costs, energy prices, and flexible solutions for grid connections. Also problems with municipalities with regard to regulations or construction licenses are discussed. Some recommendations are given to stimulate the market for small wind turbines. 1 fig., 1 ref

1990-01-01

150

Airfoil design for horizontal axis wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The interest in tailor made airfoils for Wind Turbines has lately increased. At FFA work is beeing done to develop new airfoils for Horizontal Axis Wind Turbines, HAWTs, within the FFA Basic Wind Energy Research program. A discussion of the desirable characteristics of airfoils for HAWTs is given and the design philosophy for a suggested 15.2% thick airfoil for the outer parts of turbine blade will be presented. Suggested thicker airfoils for the inner blade is also presented. (author) 16 refs.

Bjoerck, A. (FFA, The Aeronautical research institute, FFA Aeronautics Lab. at KTH, Stockholm (SE))

1989-01-01

151

Small Wind Research Turbine: Final Report  

Energy Technology Data Exchange (ETDEWEB)

The Small Wind Research Turbine (SWRT) project was initiated to provide reliable test data for model validation of furling wind turbines and to help understand small wind turbine loads. This report will familiarize the user with the scope of the SWRT test and support the use of these data. In addition to describing all the testing details and results, the report presents an analysis of the test data and compares the SWRT test data to simulation results from the FAST aeroelastic simulation model.

Corbus, D.; Meadors, M.

2005-10-01

152

Optimization of wind turbine rotors  

Energy Technology Data Exchange (ETDEWEB)

The Constrained Steepest Descent method has been applied to the optimization of wind turbine rotors through the development of a numerical model. The model consists of an optimization kernel, an aerodynamic model, a structural dynamic model of a rotating beam, and a cost model for the wind turbine. The cost of energy is minimized directly by varying the blade design, the rotational speed and the resulting design of the drive-train and tower. The aerodynamic model is a combination of a fast engineering model based on strip-theory and two and three-dimensional Euler solvers. The two-dimensional Euler solver is used for generation of pre-stall airfoil data. Comparisons with experimental data verify that the engineering model effectively approximates non-stalled flow, except at the blade tip. The three-dimensional Euler solver is in good agreement with the experimental data at the tip, and is therefore a useful supplement for corrections of the tip-loss model, and evaluation of an optimized design. The structural dynamic model evaluates stresses and deformations for the blade. It is based on constitutive relations for a slender beam that are solved with the equations of motions using a finite-difference method. The cost model evaluates the design change of the wind turbine and the resulting costs that occur when a change in blade design modifies the blade mass and the overall forces. The cost model is based on engineering design rules for the drive-train and tower. The model was applied using a Danish 600 kW wind turbine as a reference. Two rotors were optimized using traditional NACA airfoils and a new low-lift airfoil family developed specifically for wind turbine purposes. The cost of energy decreased four percent for the NACA rotor, and seven percent for the low-lift rotor. Optimizations with a high number of degrees of freedom show that a designer has considerable flexibility in choosing some primary parameters such as rated power and rotor diameter, if the rest of the parameters are optimized. The model requires modest computer resources, and seems to be well suited for use as an industrial design tool. (author)

Nygaard, Tor Anders

1999-07-01

153

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

Energy Technology Data Exchange (ETDEWEB)

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

154

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

Energy Technology Data Exchange (ETDEWEB)

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

155

Background sound levels and wind turbine noise  

International Nuclear Information System (INIS)

[en] This paper reviewed the regulators' approach to the challenge of establishing sound level limits in wind turbine arrays that allow for variations in background sound level with wind speed. Wind speed influences the amount of noise produced by wind turbines and also the noise associated with wind passing over terrain and through foliage. New guidelines by Ontario's Ministry of the Environment were discussed along with wind noise as a function of speed in remote locations having a variety of terrain and foliage types. It was concluded that wind induced noise can effectively mask the steady noise of wind turbine generators, especially during high wind conditions. The extent of wind induced noise depends on the local terrain, foliage and wind speed through vegetation. Masking wind turbine noise by wind induced noise in vegetation can be reduced during stable atmospheric conditions which are common at night. The extent of masking by wind induced noise depends on the level and characteristics of wind turbine noise and wind induced noise. 9 refs., 2 tabs., 2 figs

2005-01-01

156

Background sound levels and wind turbine noise  

Energy Technology Data Exchange (ETDEWEB)

This paper reviewed the regulators' approach to the challenge of establishing sound level limits in wind turbine arrays that allow for variations in background sound level with wind speed. Wind speed influences the amount of noise produced by wind turbines and also the noise associated with wind passing over terrain and through foliage. New guidelines by Ontario's Ministry of the Environment were discussed along with wind noise as a function of speed in remote locations having a variety of terrain and foliage types. It was concluded that wind induced noise can effectively mask the steady noise of wind turbine generators, especially during high wind conditions. The extent of wind induced noise depends on the local terrain, foliage and wind speed through vegetation. Masking wind turbine noise by wind induced noise in vegetation can be reduced during stable atmospheric conditions which are common at night. The extent of masking by wind induced noise depends on the level and characteristics of wind turbine noise and wind induced noise. 9 refs., 2 tabs., 2 figs.

Parkinson, J.P. [HFP Acoustical Consultants Corp., Calgary, AB (Canada)

2005-07-01

157

Implementation of Pitch Control Of wind Turbine Using Simulink (Matlab)  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, it is shown that how the variable speed wind turbine can be used to generate a fixed value of voltage at the output with the help of a pi controller and it is done by varying the pitch angle of the blades Pitch angle control is the most common means for adjusting the aerodynamic torque of the wind turbine when wind speed is above rated speed and various controlling variables may be chosen, such as wind speed, generator speed and generator power. As conventional pitch control usually use PI controller, the mathematical model of the system should be known well. The block diagram of the proposed speed control system which consists of speed controller, actuator model and the turbine linearized model is simulated by Matlab-Simulink software package. the simulation results show that the controller accurately adjusts the blade pitch angle to set the wind turbine power output to its reference value.

Sachin Khajuria, Jaspreet Kaur

2012-01-01

158

Improved performance of wind turbines using fibre optic structural monitoring  

Energy Technology Data Exchange (ETDEWEB)

This development programme, which will run from December 2004 to September 2006, aims to deliver a condition monitoring system suitable for mass deployment across the UK wind industry that will reduce operating costs and improve design load understanding, operational efficiency, reliability and public safety. The project involves the development of a complete fibre optic structural monitoring system for the wind turbine blades and hub structure. The proposed system will offer significant operational benefits to the developers and users of utility-scale wind turbines. The project's objectives are to: develop a cost-effective strain and temperature sensing system suitable for long-term deployment; carry out functional and environmental stress testing to ensure measurement accuracy (both short and long term); develop a technique to embed the fibre optic sensors in composite wind turbine blades during manufacturing; and develop a technique for retrofitting the sensors to existing wind turbines.

NONE

2005-01-15

159

Operation and control of large wind turbines and wind farms  

Energy Technology Data Exchange (ETDEWEB)

This report is the final report of a Danish research project 'Operation and control of large wind turbines and wind farms'. The objective of the project has been to analyse and assess operational strategies and possibilities for control of different types of wind turbines and different wind farm concepts. The potentials of optimising the lifetime/energy production ratio by means of using revised operational strategies for the individual wind turbines are investigated. Different strategies have been simulated, where the power production is decreased to an optimum when taking loads and actual price of produced electricity into account. Dynamic models and control strategies for the wind farms have also been developed, with the aim to optimise the operation of the wind farms considering participation in power system control of power (frequency) and reactive power (voltage), maximise power production, keep good power quality and limit mechanical loads and life time consumption. The project developed models for 3 different concepts for wind farms. Two of the concepts use active stall controlled wind turbines, one with AC connection and one with modern HVDC/VSC connection of the wind farm. The third concept is based on pitch controlled wind turbines using doubly fed induction generators. The models were applied to simulate the behaviour of the wind farm control when they were connected to a strong grid, and some initial simulations were performed to study the behaviour of the wind farms when it was isolated from the main grid on a local grid. Also the possibility to use the available information from the wind turbine controllers to predict the wind speed has been investigated. The main idea has been to predict the wind speed at a wind turbine using up-wind measurements of the wind speed in another wind turbine. (au)

Soerensen, Poul; Hansen, Anca D.; Thomsen, Kenneth (and others)

2005-09-01

160

Spatial planning of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

This paper proposes guidelines for spatial planning for wind power, based on experience with spatial planning in Belgium, Denmark, France and the Netherlands. In addition experiences from Germany and Ireland have been used. This guidelines quotes all decisive criteria for successful implementation of wind energy: landscape integration, stakeholders involvement, noise and distance from buildings. (author)

NONE

2004-01-01

 
 
 
 
161

Noise annoyance from wind turbines a review  

International Nuclear Information System (INIS)

[en] This study summarises present knowledge on noise perception and annoyances from wind turbines in areas were people live or spend recreation time. There are two main types of noise from a wind turbine: mechanical noise and aerodynamic noise. The aerodynamic noise emits from the rotor blades passing the air. It has a swishing character with a modulation that makes it noticeable from the background noise. This part of the wind turbine noise was found to be the most annoying. Field studies performed among people living in the vicinity of wind turbines showed that there was a correlation between sound pressure level and noise annoyance, but annoyance was also influenced by visual factors such as the attitude to wind turbines' impact on the landscape. Noise annoyance was found at lower sound pressure levels than in studies of annoyance from traffic noise. There is no scientific evidence that noise at levels created by wind turbines could cause health problems other than annoyance. No studies on noise from wind turbines in wilderness areas have been found, but the reaction to other noise sources such as aircraft have been studied. In recreational areas, the expectation of quietness is high among visitors, but wind turbines are, in contrary to aircraft, stationary and could be avoided by recreationists. The visual impact of wind turbines might though be the dominant source of annoyance. Regulations on noise from wind turbines are based on different principles. Some states, e.g. Denmark, have a special legislation concerning wind turbines, while others, like Sweden, have used recommendations originally developed for a different noise source. The noise level could either be absolute, as in Germany, or related to the background noise level as in France. This background noise level could be standardised, measured or related to wind speed

2003-01-01

162

Noise annoyance from wind turbines a review  

Energy Technology Data Exchange (ETDEWEB)

This study summarises present knowledge on noise perception and annoyances from wind turbines in areas were people live or spend recreation time. There are two main types of noise from a wind turbine: mechanical noise and aerodynamic noise. The aerodynamic noise emits from the rotor blades passing the air. It has a swishing character with a modulation that makes it noticeable from the background noise. This part of the wind turbine noise was found to be the most annoying. Field studies performed among people living in the vicinity of wind turbines showed that there was a correlation between sound pressure level and noise annoyance, but annoyance was also influenced by visual factors such as the attitude to wind turbines' impact on the landscape. Noise annoyance was found at lower sound pressure levels than in studies of annoyance from traffic noise. There is no scientific evidence that noise at levels created by wind turbines could cause health problems other than annoyance. No studies on noise from wind turbines in wilderness areas have been found, but the reaction to other noise sources such as aircraft have been studied. In recreational areas, the expectation of quietness is high among visitors, but wind turbines are, in contrary to aircraft, stationary and could be avoided by recreationists. The visual impact of wind turbines might though be the dominant source of annoyance. Regulations on noise from wind turbines are based on different principles. Some states, e.g. Denmark, have a special legislation concerning wind turbines, while others, like Sweden, have used recommendations originally developed for a different noise source. The noise level could either be absolute, as in Germany, or related to the background noise level as in France. This background noise level could be standardised, measured or related to wind speed.

Pedersen, Eja [Halmstad Univ., Halmstad (Sweden). School of Business and Engineering

2003-08-01

163

Large superconducting wind turbine generators  

DEFF Research Database (Denmark)

To realize large (>10 MW) direct-driven off-shore wind turbines, a number of steps are needed to reduce weight and cost compared to on-shore technologies. One of the major challenges is to provide drive trains which can comply with the large torque as the turbine rotor diameter is scaled up and the rotation speed is lowered in order to limit the tip speed of the blades. The ability of superconducting materials to carry high current densities with very small losses might facilitate a new class of generators operating with an air gap flux density considerably higher than conventional generators and thereby having a smaller size and weight [1, 2]. A 5 MW superconducting wind turbine generator forms the basics for the feasibility considerations, particularly for the YBCO and MgB2 superconductors entering the commercial market. Initial results indicate that a 5 MW generator with an active weight of 34 tons, diameter of 4.2 m and length of 1.2 m can be realized using superconductors carrying 300 A/mm2 in a magnetic field of 4 T and an air gap flux density of the order 2.5 T. The results are compared to the performance of available superconductors, as well as the near future forecasted performance.

Abrahamsen, Asger Bech; Magnusson, Niklas

2012-01-01

164

Computational Aerodynamics and Aeroacoustics for Wind Turbines  

DEFF Research Database (Denmark)

To analyse the aerodynamic performance of wind turbine rotors, the main tool in use today is the 1D-Blade Element Momentum (BEM) technique combined with 2D airfoil data. Because of its simplicity, the BEM technique is employed by industry when designing new wind turbine blades. However, in order to obtain more detailed information of the flow structures and to determine more accurately loads and power yield of wind turbines or cluster of wind turbines, it is required to resort to more sophisticated techniques, such as Computational Fluid Dynamics (CFD). As computer resources keep on improving year by year (about ten times every five years from statistics over the last twenty years), CFD has now become a popular tool for studying the aerodynamics of wind turbines. The present thesis consists of 19 selected papers dealing with the development and use of CFD methods for studying the aerodynamics and aero-acoustics of wind turbines. The papers are written in the period from 1997 to 2008 and numbered according tothe list in page v. The work consists of two parts: an aerodynamic part based on Computational Fluid Dynamics and an aero-acoustic part based on Computational Aero Acoustics for wind turbines. The main objective of the research was to develop new computational tools and techniques for analysing flows about wind turbines. A few papers deal with applications of Blade Element Momentum (BEM) theory to wind turbines. In most cases the incompressible Navier-Stokes equations in primitive variables (velocity-pressure formulation) are employed as the basic governing equations. However, since fluid mechanical problems essentially are governed by vortex dynamics, it is sometimes advantageous to use the concept of vorticity (defined as the curl of velocity). In vorticity form the Navier-Stokes equations may be formulated in different ways, using a vorticity-stream function formulation, a vorticity-velocity formulation or a vorticity-potential-stream function formulation. In [1] - [3] two different vorticity formulations were developed for 2D and 3D wind turbine flows. In [4] and [5] numerical techniques for avoiding pressure oscillations were developed when solving the velocity-pressure coupling system in the in-house EllipSys2D/3D code, which originally was developed in a cooperation between DTU (Michelsen, 1992) and Risø (Sørensen, 1995). In [6] – [8] different actuator disc techniques combined with CFD are presented. This includes actuator disc, actuator line and actuator surface techniques, which were developed to simulate flows past one or more wind turbines. In [9] and [10] a tip loss correction method that improves the conventional models was developed for use in combination with BEM or actuator/Navier-Stokes computations. A simple and efficient technique for determining the angle of attack for flow past a wind turbine rotor was developed in [11], and in [12] tunnel wall corrections for wind tunnels with closed or open test sections were developed. The second part of the thesis deals with Computational Aero-Acoustics (CAA). With the spread of wind turbines near urban areas, there is an increasing need for accurate predictions of aerodynamically generated noise. Indeed, noise has become one of the most important issues for further development of wind power, and the ability of controlling and minimising noise emission may be advantageous when competing on the world energy market. To predict generation and propagation of aerodynamic noise, it is required to solve the compressible Navier-Stokes equations. As the scales of the flow and the acoustic waves are quite different (about 1/M, M=Mach number=U/c), it is difficult to resolve them together at the same time. Hardin and Pope proposed a non-linear two-step (viscous incompressible flow and inviscid acoustic perturbation) splitting procedure for computational aero-acoustics that is suitable for both generation and propagation. The advantage of the splitting approach, as compared to the acoustic analogies, is that the source strength is obtained directly and that it account

Shen, Wen Zhong

2009-01-01

165

Status of local planning for wind turbines. Vol. 2: Jutland. Wind turbines - January 1997  

International Nuclear Information System (INIS)

Information on the status of individual municipalities regarding wind turbine power plans, the content of the plans themselves, key figures on existing wind turbines for each municipality, overall plans for wind power development and key figures for development of wind power in Jutland - in addition to maps and lists of local authorities with either a high or a low coverage of electric power by wind turbines either now or in the future - are found in this volume. (EG).

1997-01-01

166

Lightning protection in wind turbines; Potzblitz  

Energy Technology Data Exchange (ETDEWEB)

Lightning protection in wind power plants is explained in detail. In view of the fact that lightning strokes may significantly shorten the life of wind turbines, manufacturers are working hard on improved protection systems.

Hautmann, Daniel

2012-09-15

167

Mitigation of Wind Power Fluctuation by Active Current Control of Variable Speed Wind Turbines  

DEFF Research Database (Denmark)

Wind shear and tower shadow are the sources of power fluctuation of grid connected wind turbines during continuous operation. This paper presents a simulation model of a MW-level doubly fed induction generator (DFIG) based variable speed wind turbine with a partial-scale back-to-back power converter in Simulink. A simple and effective method of wind power fluctuations mitigation by active current control of DFIG is proposed. It smoothes the generator output active power oscillations by adjusting the active current of the DFIG, such that the power oscillation is stored as the kinetic energy of the wind turbine. The simulations are performed on the NREL 1.5MW upwind reference wind turbine model. The simulation results are presented and discussed to demonstrate the validity of the proposed control method.

Zhang, Yunqian; Chen, Zhe

2013-01-01

168

Harmonisation of European wind turbine certification  

Energy Technology Data Exchange (ETDEWEB)

The present situation in wind turbine certification - characterised by a co-existence of different wind turbine certification systems - hampers the trade of wind turbines in Europe. This situation has many negative implications on the implementation of wind energy in political, commercial, environmental and legal sense. The EWTC project was set up in the FP4 (Joule 3 Programme) by four certification bodies in Europe to tackle this problem on the 'technical level'. The project partners have carried out parallel certifications to determine specific interpretation differences in design evaluation of wind turbines, using IEC 61400-1 and IEC WT 01 as a common basis. The partners have streamlined their conclusions towards common Guidelines for Design Evaluation of Wind Turbines to be used together with the existing standards and regulations. The project team also formulated recommendations on how to implement the Guidelines in a formal way in Europe. 5 refs.

Van Hulle, F.J.L [ECN Wind, Petten (Netherlands); Nath, C. [GL Wind, Hamburg (Germany); Hjuler Jensen, P. [Risoe, Roskilde (Denmark); Eriksson, C. [DNV, Hellerup (Denmark); Vionis, P. [CRES, Pikermi (Greece)

2001-09-01

169

Development of vertical axis wind turbine  

Energy Technology Data Exchange (ETDEWEB)

This paper traces the development of the vertical axis wind turbine (VAWT) from 1926 when a Frenchman, Darrieus, first patented a curved bladed wind turbine to the current UK development of a straight bladed VAWT. The Darrieus VAWT was rediscovered in 1966 and extensively developed at modest size in Canada and USA. Currently there are more than 100 VAWTs of this type in windfarms in California and scattered around Canada. In the UK the Department of Energy is interested in the development of large multi-megawatt wind turbines for supply of electricity to the grid from wind farms possibly sited offshore. Vertical Axis Wind Turbines Ltd (VAWT Ltd), with support funding from the Department, is developing the straight bladed vertical axis wind turbine to large size. (author).

Clare, R.; Mays, I.D. (Sir Robert McAlpine and Sons Ltd. (GB))

1989-10-01

170

Anisotropy of turbulence in wind turbine wakes  

Energy Technology Data Exchange (ETDEWEB)

This work is mainly dedicated to the study of non-isotropic characteristics of turbulence in wind turbine wakes, specifically the shear layer of the near wake. A calculation method based on an explicit algebraic model for the components of the turbulent stress tensor is proposed, and the results are found to be in acceptable agreement with experimental results. Analytical expressions for the estimation of an upper limit of the global turbulence kinetic energy, k, and the individual contributions of each diagonal term in the turbulent stress tensor are proposed. Their predictions are compared with experimental results.

Gomez-Elvira, Rafael [Comision Nacional de Energia (Spain); Crespo, Antonio; Migoya, Emilio; Manuel, Fernando [Departamento de Ingenieria Energetica y Fluidomecanica, Escuela Tecnica Superior de Ingenieros Industriales, Universidad Politecnica de Madrid, Jose Gutierrez Abascal, 2. 28006 Madrid (Spain); Hernandez, Julio [Departamento de Mecanica, ETSII, Universidad Nacional de Educacion a Distancia, Ciudad Universitaria, 28040 Madrid (Spain)

2005-10-01

171

Mechanical noise from wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Community annoyance due to noise from wind turbines is often the result of noise character rather than level. Although the overall contributions from each of the two main classes of noise source, namely aerodynamic and mechanical, are often of a similar order for an untreated turbine, it is usually the mechanical sources which provide the dominant noise characteristics that may lead to annoyance. In this paper, the sources of mechanical noise are identified primarily with reference to HAWTs and then attention is concentrated on the rotor-shaft step-up gearbox, which is normally the top-ranking source. The major gearbox noise mechanisms and transmission paths are discussed and reference made to Noise Specifications and procedures applicable to the gearbox prior to its installation. The reduction of machinery noise is reviewed both at source and by treatment of transmission paths. (author)

Pinder, J.N. (Southampton Univ. (United Kingdom). Inst. of Sound and Vibration Research)

1992-01-01

172

Mechanical noise from wind turbines  

International Nuclear Information System (INIS)

[en] Community annoyance due to noise from wind turbines is often the result of noise character rather than level. Although the overall contributions from each of the two main classes of noise source, namely aerodynamic and mechanical, are often of a similar order for an untreated turbine, it is usually the mechanical sources which provide the dominant noise characteristics that may lead to annoyance. In this paper, the sources of mechanical noise are identified primarily with reference to HAWTs and then attention is concentrated on the rotor-shaft step-up gearbox, which is normally the top-ranking source. The major gearbox noise mechanisms and transmission paths are discussed and reference made to Noise Specifications and procedures applicable to the gearbox prior to its installation. The reduction of machinery noise is reviewed both at source and by treatment of transmission paths. (author)

1992-06-30

173

Aeroacoustic (noise) measurements on wind turbines  

Energy Technology Data Exchange (ETDEWEB)

This paper presents aeroacoustic measurement on wind turbines. The Waterloo wind energy research group focused on wind turbine aerodynamics and aeroacoustics. They conducted small-scale experiments on airfoils, and large-scale experiments on turbines. The motivation came from the concern over wind turbine sound emissions. The aim was to design, fabricate, calibrate and test low-cost microphone arrays for wind turbine noise applications. Background information on areas such as sound, beam forming, wind turbine and airfoil noise is given. Two types of microphone are generally used, condenser or electret. The experimental setup for data acquisition on a large-scale array monopole source is given. Results at 333m and 5kHz are shown. A large-scale array wind turbine of 600W was also evaluated. The results are given. From these results it was concluded that LSA correctly located and isolated multiple sources; measurements of 600W wind turbine at 5.5 m/s wind speed show substantial evidence of trailing edge noise. The paper concludes with recommendations for future work.

Johnson, David; Bale, Adam [University of Waterloo (Canada)

2011-07-01

174

Optimization of wind turbine rotors  

Energy Technology Data Exchange (ETDEWEB)

A computer program for aerodynamic optimization of wind turbine rotors has been written in Fortran with the purpose to maximize the annual energy production. The constraints is the maximum power output from the turbine and maximum and minimum values on the design variables. The design of the rotor is described by the chord- and twist distribution. The chord- and twist distributions are described with Bezier splines which, with a few number of control points, are very flexible. The Bezier control points are the design variables which are optimized by the optimization program. The optimization method used in the program is the Method of Moving Asymptotes, MMA, suggested by Krister Svanberg at the Royal Institute of Technology in Stockholm. MMA is a stable method and it seems suitable for this application. It is also in general easy to implement constraints. It seems like there are many local maximum points and the variations in the annual energy production between the total maximum points are very small, so there are many solutions to choose between and finding the global maximum point can be a problem. The problem could possibly be avoided with smaller wind steps near the rated wind. In future versions of the optimization program the Reynolds number dependents of the aerodynamic coefficients should be taken into consideration. Constraints for the thrust and the aerodynamic noise should also be implemented in the program 8 refs, 8 figs, 13 tabs, 14 appendixes

Holmkvist, Jonas

1998-05-01

175

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

Energy Technology Data Exchange (ETDEWEB)

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

176

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

Energy Technology Data Exchange (ETDEWEB)

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

177

Wake effects on wind turbine performance  

Energy Technology Data Exchange (ETDEWEB)

Introduction. In existing wind farms, where it is impossible to change the distance between turbines, it is likely that the overall wind farm efficiency can be improved by strategically control of the power extraction of the individual turbines. One of the ways to achieved this is by changing the yaw angle of the upstream turbines. This change can significantly affect the performance of the upstream turbines and hence, their wake properties and therefore, the performance of the turbines further downstream. This study presents a wind tunnel study of the performance characteristics of a model wind turbine operating in the wake of another turbine operating at yawed condition. This information might be useful for validation of computational studies, and also provide a better understanding of the overall flow structure, helping proper planning and designing of wind farms. Experimental Approaches. The experiments were performed in a low-speed, closed-return wind tunnel with a test section of 1.9 m (height) x 2.7 m (width) x 11.0 m (length). For this study, two model turbines with 3-bladed upwind rotors and the same rotor diameter of 0.90 m were used. The torque generated by the wind turbine was measured directly by a torque sensor mounted on the rotor shaft. The downstream turbine is located at three rotor diameters from the upstream turbine and the upstream yaw angle was varied from 0 to 30 degree. Overview of Results. It was observed that as the upstream turbine yaw angle increases there is a gradual increase in the power coefficient of the downstream turbine at a given tip speed ratio except within the stalled region. This is because operating the upstream turbine in yaw, less power may be extracted from the air flow by the upstream turbine. The downstream turbine is therefore exposed to higher wind speed compared to when the turbines are in an in-line arrangement. This results in the improved performance of the downstream turbine. For a constant rotor speed, it was observed that with increasing yaw angle of the upstream turbine, the cut-in wind speed at which the downstream turbine can start producing power is slightly reduced. The normalized maximum power coefficient shows that the gain in relative maximum power coefficient of the downstream turbine increases with increasing yaw angle of the upstream turbine. At a yaw angle of 10 deg. the gain is only about 4% compared to when the upstream turbine is operating in non-yawed position, and this increases to about 29% at yaw angle of 40 deg. (the largest yaw angle considered in this study). In addition, it was found that by operating the upstream turbine at appropriate yaw angle and using a relatively small distance of separation between the turbines, the efficiency of the wind farm (two model wind turbines) is comparable to when the distance between them is high and the upstream turbine is not yawed. Therefore, operating the upstream turbine at a suitable yaw angle will not only improve the total wind farm power output but will also reduce the space required for a given wind farm. (Author)

Adaramola, Muyiwa S.; Krogstad, Per-Aage

2010-07-01

178

Seaside, mountain and... wind turbines  

International Nuclear Information System (INIS)

Several courts have given a ruling considering that the law 'Montagne' (January 9., 1985) and the law 'Littoral' (January 3., 1986) are opposable to the building license of wind turbines. The law 'Littoral' imposes that any new construction in seaside areas has to be built in continuity of existing villages or hamlets. The law 'Montagne' imposes similar constraints to avoid the construction of isolated buildings in mountain areas but, contrary to the law 'Littoral', it allows some impairment for instance for the construction of certain public equipment. (A.C.)

2011-01-01

179

Permanent orientation wind turbines: a preliminary feasibility study  

Energy Technology Data Exchange (ETDEWEB)

The present paper examines the possibility of developing a fixed orientation wind turbine to be used at locations with strong prevailing winds. In the paper the wind energy distribution data from several Aegean islands are used as a reference. The preliminary results tend to indicate that the energy losses in some sites are not prohibitive. Therefore, the simplification and cost reduction afforded by a fixed orientation wind turbine may well lead to a more cost effective unit. The paper also proposes a method based on Fourier analysis for the estimation of the optimum orientation angle. (author)

Sparis, P.D.; Papadopoulos, D. (Democritus Univ. of Thrace (Greece). Polytechnic School of Xanthi)

1993-01-01

180

Multilevel converters for 10 MW Wind Turbines  

DEFF Research Database (Denmark)

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 time and cost of the converter. Simulation results of different converter candidates regarding the loss and junction temperature are presented and analyzed. It is concluded that the three-level and five-level H-bridge converter topologies both have potential to achieve improved thermal performances compared to the three-level Neutral-Point-Clamped converter topology in the wind power application.

Ma, Ke; Blaabjerg, Frede

2011-01-01

 
 
 
 
181

OUT Success Stories: Wind Turbine Development  

Energy Technology Data Exchange (ETDEWEB)

Cost-shared projects with the U.S. Department of Energy and the wind industry have produced new, commercially available turbines that generate power at low costs. Advanced wind turbine technologies will be instrumental for the United States and other countries in meeting their commitments to reduce greenhouse gases.

Jones, J.; Green, B.

2000-08-31

182

When wind turbines go to the sea  

International Nuclear Information System (INIS)

Land wind turbines are not designed to operate in the open seas. In order to enhance their reliability, facilitate their maintenance and increase their power, existing technologies are adapted to the offshore constraints (direct drive for the blades, maintenance optimization, etc.) while innovating designs (such as vertical axis wind turbines, floating platforms, etc.) are presently tested. Several of these new concepts are described

2010-01-01

183

OUT Success Stories: Wind Turbine Development  

International Nuclear Information System (INIS)

Cost-shared projects with the U.S. Department of Energy and the wind industry have produced new, commercially available turbines that generate power at low costs. Advanced wind turbine technologies will be instrumental for the United States and other countries in meeting their commitments to reduce greenhouse gases.

2000-01-01

184

IEA Joint action. Aerodynamics of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The 9th Symposium on Aerodynamics of Wind Turbines was organized in Stockholm, from the 11th until 12th December 1995. 16 contributions on vortex aerodynamics, stall regulated wind turbines, high-lift airfoils and other rotor-related topics were presented. (EG)

Maribo Pedersen, B. [ed.

1995-12-31

185

Voltage Quality of Grid Connected Wind Turbines  

DEFF Research Database (Denmark)

Grid connected wind turbines may cause quality problems, such as voltage variation and flicker. This paper discusses the voltage variation and flicker emission of grid connected wind turbines with doubly-fed induction generators. A method to compensate flicker by using a voltage source converter (VSC) based STATCOM is presented, which shows it is an efficient mean to improve voltage quality.

Chen, Zhe; Blaabjerg, Frede

2004-01-01

186

Atmospheric icing on large wind turbine blades  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A numerical study of atmospheric ice accretion on a large horizontal axis ‘NREL 5 MW’ wind turbine blade has been carried out using the computational fluid dynamics based technique. Numerical analyses were carried out at five different sections along the wind turbine blade for both rime and glaze ...

Muhammad S. Virk, Matthew C. Homola, Per J. Nicklasson

187

Dynamic Response of Flexible Wind Turbine Blade  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Aiming at the non-stationary and stall flutter problems of wind turbine blade caused by transient load fluctuations, the dynamic properties of wind turbine were studied, the blade was simplify to a cantilever beam in case of the action of shear deformation and cross section rotating effect we...

Yu-qiao Zheng; Rong-zhen ZHAO; Hong liu

188

Experimental Research for MW Wind Turbine Blade  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of this study was get acquiring dependable results of MW wind turbine blade performance at work condition to design new-style blade. Most of the research study on structural analysis of wind turbine blade by make model test and use the finite element, but there were certain differen...

Fu Jie; Song Lin-Hui; He Bin; Fan Qin-Shan

189

Testing of rotor blades of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The trend within the wind power industry to develop ever larger wind turbines was discussed. In addition to marketing advantages to having the largest, fastest and best turbine, there are also technical and economical reasons for upscaling, particularly for offshore wind turbines, where installation, maintenance, offshore cables and foundation costs do not fully scale to the diameter of the turbine. However, the square-cube law presents a major challenge to the economical upscaling of the wind turbine. As wind turbines reach 200 m diameter and rotor blades approach 90 m in length, major investments are needed to develop new concepts. Rotor blade certification is a major cost factor. As such, the wind power industry is seeking to optimize this process which involves material tests as well as static and cyclic testing of the blade which can take over half a year to complete. Fatigue testing of rotor blades is becoming increasingly costly and time-consuming with the increasing size of wind turbines. Alternative test method, based on static blade tests and component tests are therefore needed. Another problem for the further development of offshore applications is the increased need for reliability of wind turbines. More extensive material tests might satisfy reliability demands at considerably lower costs. 9 refs., 7 figs.

Van Wingerde, A. [Fraunhofer Center for Wind Energy and Marine Engineering, Bremerhaven (Germany)

2008-07-01

190

Aerodynamic interference between two Darrieus wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

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

1981-04-01

191

Discord amongst the wind turbine buyers with regard to Dutch wind turbine manufacturers  

International Nuclear Information System (INIS)

[en] In the Netherlands two medium-large manufacturers of wind turbines exist: NedWind (Hollandia Kloos) and Windmaster Nederland (Begemann Groep). Also Lagerwey, which constructs wind turbines for the private market (farmers, cooperatives), is important for the Dutch market and successfull in Germany. There is a tendency amongst the Dutch energy utilities, which cooperate in the foundation WindPlan, to buy wind turbines from foreign manufacturers. Some energy utilities want to take advantage of the most attractive offers, while others want to cooperate in building up a Dutch wind turbine industry. 5 ills

1992-01-01

192

Superconductivity for Large Scale Wind Turbines  

Energy Technology Data Exchange (ETDEWEB)

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

193

Lightning protection system for a wind turbine  

Science.gov (United States)

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); Petter, Jeffrey K. (Williston, VT)

2008-05-27

194

Control of variable speed wind turbines  

Energy Technology Data Exchange (ETDEWEB)

A variable speed, fixed pitch wind turbine is difficult to control: it is stable at below rated wind speeds but becomes unstable as power output is limited by stalling the turbine at above rated wind speeds. This turbine is suitable especially for small, sub-100 kW wind power plants as we can avoid the use of a costly and failure-prone pitch mechanism. The aerodynamic torque of the turbine is considered a disturbance to be cancelled by feedforward control. The torque cannot be measured and is estimated by a Kalman filter as an extended state. The estimated aerodynamic torque is also used to define a rotational speed reference and to restrict the power input. In addition, a fuzzy controller is designed and compared to a previous one. A turbine and wind field are modelled for the Kalman filter to operate. The Kalman filter yields a good estimate of rotational speed from noisy measurement. In laboratory tests, both 100 kW and 300 W generators and frequency converters were subjected to variable wind torque. Both control algorithms, feedforward and fuzzy, operated satisfactorily. The tests showed that a Kalman filter must be used to give the fuzzy controller a good estimate of aerodynamic torque. Power output was controlled at all above-rated wind speeds. In the small turbine, maximum power was also restricted from 300 W down to 50 W without problems. The small wind turbine was also tested in a wind tunnel and in field conditions. (orig.)

Vihriaelae, H.

2002-07-01

195

'Wind turbine syndrome': fact or fiction?  

UK PubMed Central (United Kingdom)

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

Farboud A; Crunkhorn R; Trinidade A

2013-03-01

196

Structural optimization study of composite wind turbine blade  

DEFF Research Database (Denmark)

In this paper the initial layout of a 2. MW composite wind turbine blade is designed first. The new airfoils families are selected to design a 2. MW wind turbine blade. The finite element parametric model for the blade is established. Based on the modified Blade Element Momentum theory, a new one-way fluid-structure interaction method is introduced. A procedure combining finite element analysis and particle swarm algorithm to optimize composite structures of the wind turbine blade is developed. The procedure proposed not only allows thickness variation but also permits the spar cap location variation over the structure. The results show that, compared to the initial blade, the mass of the optimized blades is reduced and especially for the scheme II (the location of blade spar cap is seen as one of the variables) which exhibit more mass saving. This present study has important significance for the structural design and optimization of wind turbine blades. © 2012.

Chen, Jin; Shen, Wen Zhong

2013-01-01

197

Power Control Design for Variable-Speed Wind Turbines  

Directory of Open Access Journals (Sweden)

Full Text Available This paper considers power generation control in variable-speed variable-pitch horizontal-axis wind turbines operating at high wind speeds. A dynamic chattering torque control and a proportional integral (PI) pitch control strategy are proposed and validated using the National Renewable Energy Laboratory wind turbine simulator FAST (Fatigue, Aerodynamics, Structures, and Turbulence) code. Validation results show that the proposed controllers are effective for power regulation and demonstrate high-performances for all other state variables (turbine and generator rotational speeds; and smooth and adequate evolution of the control variables) for turbulent wind conditions. To highlight the improvements of the provided method, the proposed controllers are compared to relevant previously published studies.

Yolanda Vidal; Leonardo Acho; Ningsu Luo; Mauricio Zapateiro; Francesc Pozo

2012-01-01

198

Factors affecting public acceptance of wind turbines in Sweden  

Energy Technology Data Exchange (ETDEWEB)

Wind power is growing in Sweden, but the high-level of opposition to turbine proposals has meant that many proposals are never realised. This opposition in a country that has a measured 74% support for wind power leads to questions being raised as to what is causing this opposition. Many have suggested that it is due to prevalent NIMBY attitudes; this, however, is only one factor affecting the public acceptance of turbines. The over-riding factor is the spatial distance between the costs incurred and the benefits derived from wind power. Perceived need for wind power, level of participation, individual considerations of visual impact and the amount to which the local community benefits determine the realisation of turbine proposals. (author)

Devlin, E.

2005-12-15

199

Frozen wind turbines; Windkraftanlagen - eisgekuehlt  

Energy Technology Data Exchange (ETDEWEB)

It happens every year. For some days there has been cold weather with freezing temperatures. When the weather changes a warm front drifts above the cold air which is in the lower layers of the atmosphere and eventually it starts raining. The precipitation will get cooled down to temperatures below the freezing point but it stays still liquid and does not freeze to solid ice. If the 'super cooled' rain hits the surface of objects which have also temperatures below 0 Celsius it will instantly turn to a layer of solid ice. This is commonly known as 'ice rain'. These effects are only a few of several problems of wind turbines at sites where icing occurs frequently or occasionally which are analysed in the EU-project 'New Icetools' (see DEWI-Magazine No. 21, August 2002). One issue in this project deals with practical experiences and observations of operators of wind turbines running under icing conditions as well as downtimes caused by icing events. The reports will be statistically analysed by using a standardised questionnaire. (orig.)

Durstewitz, M. [Institut fuer Solare Energieversorgungstechnik (ISET), Kassel (Germany)

2003-02-15

200

Wind Turbine Converter Control Interaction with Complex Wind Farm Systems  

DEFF Research Database (Denmark)

This study presents wind turbine converter stability analysis of wind farms in frequency domain. The interaction between the wind turbine control system and the wind farm structure in wind farms is deeply investigated. Two wind farms (i.e. Horns Rev II and Karnice) are taken into consideration in this study. It is shown that wind farm components, such as long high-voltage alternating current cables and park transformers, can introduce significant low-frequency series resonances seen from the wind turbine terminals that can affect wind turbine control system operation and overall wind farm stability. The same wind turbine converter control strategy is evaluated in two different wind farms. It is emphasised that the grid-side converter controller should be characterised by sufficient harmonic/noise rejection and adjusted depending on wind farms to which it is connected. Various stability indices such as gain margin, vector gain margin and phase margin are used in order to emphasise the differences between the two wind farms.

Kocewiak, Lukasz Hubert; Bak, Claus Leth

2013-01-01

 
 
 
 
201

Smart structure for small wind turbine blade  

Science.gov (United States)

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

202

Meteorological aspects of siting large wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

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

1981-01-01

203

Illustration of Modern Wind Turbine Ancillary Services  

Directory of Open Access Journals (Sweden)

Full Text Available Increasing levels of wind power penetration in modern power systems has set intensively high standards with respect to wind turbine technology during the last years. Security issues have become rather critical and operation of wind farms as conventional power plants is becoming a necessity as wind turbines replace conventional units on the production side. This article includes a review of the basic control issues regarding the capability of the Doubly Fed Induction Generator (DFIG) wind turbine configuration to fulfill the basic technical requirements set by the system operators and contribute to power system security. An overview of ancillary services provided by wind turbine technology nowadays is provided, i.e., fault ride-through capability, reactive power supply and frequency-active power control.

Ioannis D. Margaris; Anca D. Hansen; Poul Sørensen; Nikolaos D. Hatziargyriou

2010-01-01

204

Flicker emission levels from wind turbines  

International Nuclear Information System (INIS)

The paper presents and verifies a method to calculate the flicker emission levels from wind turbines connected to power distribution systems. The idea of the method is to measure the flicker emission level from a wind turbine with reference conditions and to use these measurements to calculate a flicker coefficient for that specific wind turbine type. This can be done as a part of the approval of a wind turbine type. The flicker coefficient can then be used to calculate the flicker emission level from any wind turbine of that type with any grid and wind conditions. A simple method to determine the total flicker emission level from a number of wind turbines is also presented and verified. The flicker coefficient method is applied to 4 Danish wind turbine types representing stall and pitch control and nominal power from 300 kW to 500 kW. The conclusion is that the flicker emission in certain cases exceeds limits which are expected to be normative in the future. (author).

1996-01-01

205

Grid-connection of wind turbines and wind farms  

Energy Technology Data Exchange (ETDEWEB)

Power generation by wind turbines is controlled by several parameters. Changes in the stationary voltage levels, voltage fluctuations, inrush currents, voltage regulation in HV/MV substations, reactive power compensation and short circuits are all essential for efficient grid connection of wind turbine arrays. (EG)

Koelbaek Jensen, K.

1993-06-01

206

Turbulence characteristics in wind-turbine wakes  

Energy Technology Data Exchange (ETDEWEB)

An analysis of the evolution of turbulence characteristics in wind-turbine wakes has been carried out. Based on experimental results and on numerical results obtained with a CFD code, complemented with some theoretical considerations, simple analytical expressions are proposed for the estimation of the turbulent kinetic energy, k, and its dissipation rate, {epsilon}. To obtain the turbulence spectra in the wake a classical law used for atmospheric turbulence is assumed, in which characteristic values of turbulence velocity and turbulence length are calculated by algebraic combinations of k and {epsilon}, so that when the effect of the wake is negligible the spectrum of the unperturbed basic flow is recovered

Crespo, A. [Mecanica de Fluidos, ETS Ingenieros Industriales, Universidad Politecnica de Madrid, Madrid (Spain); Hernandez, J. [ETS Ingenieros Industriales, Madrid (Spain)

1996-06-01

207

Offshore wind turbines reliability, availability and maintenance  

CERN Multimedia

The first book to specifically focus on offshore wind turbine technology and which addresses practically wind turbine reliability and availability. The book draws on the author's experience of power generation reliability and availability and the condition monitoring of that plant to describe the problems facing the developers of offshore wind farms and the solutions available to them to raise availability, reduce cost of energy and improve through life cost.

Tavner, Peter

2012-01-01

208

Model Predictive Control of Wind Turbines  

DEFF Research Database (Denmark)

Wind turbines play a major role in the transformation from a fossil fuel based energy production to a more sustainable production of energy. Total-cost-of-ownership is an important parameter when investors decide in which energy technology they should place their capital. Modern wind turbines are controlled by pitching the blades and by controlling the electro-magnetic torque of the generator, thus slowing the rotation of the blades. Improved control of wind turbines, leading to reduced fatigue loads, can be exploited by using less materials in the construction of the wind turbine or by reducing the need for maintenance of the wind turbine. Either way, better total-cost-of-ownership for wind turbine operators can be achieved by improved control of the wind turbines. Wind turbine control can be improved in two ways, by improving the model on which the controller bases its design or by improving the actual control algorithm. Both possibilities have been investigated in this thesis. The level of modeling detail has been expanded as dynamic in ow has been incorporated into the control design model where state-of-the-art controllers usually assume quasi-steady aerodynamics. Floating wind turbines have been suggested as an alternative to ground-fixed wind turbines as they can be placed at water depths usually thought outside the realm of wind turbine placement. The special challenges posed by controlling a floating wind turbine have been addressed in this thesis. Model predictive control (MPC) has been the foundation on which the control algorithms have been build. Three controllers are presented in the thesis. The first is based on four different linear model predictive controllers where appropriate switching conditions determine which controller is active. Constraint handling of actuator states such as pitch angle, pitch rate and pitch acceleration is the primary focus of this controller. The wind turbine is a highly nonlinear plant and a gain scheduling or relinearizing model predictive controller forms the next step to improve performance compared to a linear controller. Finally, a nonlinear model predictive controller has been devised and tested under simplified conditions. At present, the nonlinear model predictive controller is however not expected to be an realistic option for real world application as the computation burden is to heavy to achieve real-time performance. This thesis is comprised of a collection scientific papers dealing with the various topics presented in this summary.

Henriksen, Lars Christian

2011-01-01

209

Estimation of fatigue life of wind turbine`s blades  

Energy Technology Data Exchange (ETDEWEB)

We estimated the fatigue life-time of a wind turbine`s blade by modified Goodman`s rule counting by the Rain-Flow procedure each values and numbers of stresses measured at TAPPI Wind Park where it is very mountainous and very rough terrain. It was concluded that the fatigue life-time of a blade at our site would be 12 years. (author)

Tsuchiya, K.; Inomata, N. [Tohoku Electric Power Co., Inc., Research and Development Center, Sendai (Japan)

1996-12-31

210

Meteorological Controls on Wind Turbine Wakes  

DEFF Research Database (Denmark)

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

Barthelmie, Rebecca J. Indiana University

2013-01-01

211

The Tjaereborg wind turbine. Final report  

Energy Technology Data Exchange (ETDEWEB)

The cooperation between the Danish Ministry of Energy and the electric utilities started in 1976 with a joint programme directed towards the development of large wind turbines, their siting and integration in the electric grid. The Tjaereborg wind turbine, a 3-bladed, horizontal axis turbine with the blades placed upwind and full span pitch control for power regulation and with the nacelle placed on a concrete tower, was connected to the electric grid in 1988. It finally came into stable operation in late 1990 after severe technical problems with the control system and gearbox. Rotor diameter is 61.1 m, blade profile is NACA 4412-43, blade length - 29 m, solidity - 5.9%, nominal speed at rated power - 22.36 rpm, tilt angle - 3 deg., hub height - 60 m. The design is based on experience gained from NIBE wind turbines. After 2 1/2 years with serious technical problems, in 1991 the turbine was released for automatic unmanned operation for 10117 hours. The general conclusion is that the electricity-producing wind turbines in the multi MW class are a viable technical possibility although the Tjaereborg turbine represents the wind turbine technology of the early eighties. A detailed technical description of this turbine is given in addition to a description of the main problems previously encountered. The system of measurement, site characteristics, operation and production, the power curve, noise emission, optimization of operation and loads are also dealt with in detail. (AB) (32 refs.).

1992-09-01

212

Wind Turbine Noise and Natural Sounds: Masking, Propagation and Modeling  

Energy Technology Data Exchange (ETDEWEB)

Wind turbines are an environmentally friendly and sustainable power source. Unfortunately, the noise impact can cause deteriorated living conditions for nearby residents. The audibility of wind turbine sound is influenced by ambient sound. This thesis deals with some aspects of noise from wind turbines. Ambient sounds influence the audibility of wind turbine noise. Models for assessing two commonly occurring natural ambient sounds namely vegetation sound and sound from breaking waves are presented in paper A and B. A sound propagation algorithm has been compared to long range measurements of sound propagation in paper C. Psycho-acoustic tests evaluating the threshold and partial loudness of wind turbine noise when mixed with natural ambient sounds have been performed. These are accounted for in paper D. The main scientific contributions are the following.Paper A: A semi-empiric prediction model for vegetation sound is proposed. This model uses up-to-date simulations of wind profiles and turbulent wind fields to estimate sound from vegetation. The fluctuations due to turbulence are satisfactory estimated by the model. Predictions of vegetation sound also show good agreement to measured spectra. Paper B: A set of measurements of air-borne sound from breaking waves are reported. From these measurements a prediction method of sound from breaking waves is proposed. Third octave spectra from breaking waves are shown to depend on breaker type. Satisfactory agreement between predictions and measurements has been achieved. Paper C: Long range sound propagation over a sea surface was investigated. Measurements of sound transmission were coordinated with local meteorological measurements. A sound propagation algorithm has been compared to the measured sound transmission. Satisfactory agreement between measurements and predictions were achieved when turbulence were taken into consideration in the computations. Paper D: The paper investigates the interaction between wind turbine noise and natural ambient noise. Two loudness models overestimate the masking from two psychoacoustic tests. The wind turbine noise is completely concealed when the ambient sound level (A-weighed) is around 10 dB higher than the wind turbine noise level. Wind turbine noise and ambient noise were presented simultaneously at the same A-weighed sound level. The subjects then perceived the loudness of the wind turbine noise as 5 dB lower than if heard alone

Bolin, Karl

2009-05-15

213

Influence of refraction on wind turbine noise  

CERN Document Server

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

Makarewicz, Rufin

2013-01-01

214

Wind turbines for a jetstream power plant  

Energy Technology Data Exchange (ETDEWEB)

The equations for energy drawn form a free airflow show that kinetic energy alone can be utilized for energy generation. For non-diffusor-augmented wind turbines it is under certain conditions possible to establish a firm relationship between speed reduction and mass flow yielding a maximum of performance. By the use of diffusors, that yield of performance per turbine surface can be further increased. The meteorological boundary conditions for the use of wind turbines in a jetstream power plant are investigated. The paper compares the use of free and diffusor-augmented wind turbines in jetstream power plants and, evaluating the weight of the individual system components, shows that diffusor-augmented wind turbines can be advantageously used in jetstream power plants.

Riegler, G.

1983-09-01

215

Fatigue loads on wind turbine blades in a wind farm  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the flap moment load spectrum in the blades on turbines operating in a wind farm and comparisons are made with a single turbine. The Swedish State Power Board is operating a small wind turbine farm situated at Alsvik on the west coast of the island of Gotland in the Baltic Sea. The farm consists of four Danwin 23/180 kW turbines. Three turbines are placed close to the shoreline in a row that runs approximately in the nort-south direction. The fourth turbine is placed to the east of the row so that the distances to the other turbines are 5, 7 and 9.5 turbine diameters. The prevailing wind direction is south-west which means that the fourth turbine often operates in the wake of another turbine. The site is favourable for wake studies since the surrounding terrain is flat and the wind often blows from the open sea. The influence of wakes on the load spectrum is important to take into account. Especially for offshore sites where the surrounding terrain does not give high load cycles due to high turbulence intensity or high wind shear. This study shows that also wakes from 9.5 diameters distance give significantly higher loads. (2 refs., 28 figs.).

Poppen, M.; Dahlberg, J.Aa.

1992-06-01

216

Load Extrapolation During Operation for Wind Turbines  

DEFF Research Database (Denmark)

In the recent years load extrapolation for wind turbines has been widely considered in the wind turbine industry. Loads on wind turbines during operations are normally dependent on the mean wind speed, the turbulence intensity and the type and settings of the control system. All these parameters must be taken into account when characteristic load effects during operation are determined. In the wind turbine standard IEC 61400-1 a method for load extrapolation using the peak over threshold method is recommended. In this paper this method is considered and some of the assumptions are examined. The statistical uncertainty related to the limited number of simulations of the response during operation is explored together with the influence of the threshold value.

Toft, Henrik Stensgaard; SØrensen, John Dalsgaard

2008-01-01

217

Active load control techniques for wind turbines.  

Energy Technology Data Exchange (ETDEWEB)

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

218

Concessions for home-made wind turbines. Vergunningen voor zelfbouwmolens  

Energy Technology Data Exchange (ETDEWEB)

Dutch jurisprudence is not adjusted yet to the use of small, home-made wind turbines. Difficulties lie in vague and indistinct concession policy. Wind turbines are divided into: mini wind turbines (up to 1 kW); small wind turbines (1-10 kW); medium sized wind turbines (10-100 kW); large or very large wind turbines. Marketing prospects for home-made wind turbines are good for mini and small wind turbines. Medium sized and large wind turbines are not of interest for do-it-yourself builders. Results of an inquiry among users of home-made wind turbines are presented. An inquiry form has been sent to 97 users; answers came in from 52 users. Licenses were issued to 38 users and refused to 14 users.

Pragt, W.

1983-01-01

219

Near wake behaviour of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

If wind turbines are to be large contributors for energy production, a large amount of turbines have to be erected. As the areas suitable for wind energy production are limited, an optimum use of these areas are needed. For that reason wind turbines have to be localised in larger or smaller wind farms. Localizing wind turbines in cluster will lead to interference between them, reducing the wind speed and generating heightened loads on downstream sited turbines. In order to build suitable wind turbines, the loads have to be investigated properly. For that reason it is important to get as good understanding of the wake behaviour as possible. In this report a simple numerical model is used to calculate the near wake of a turbine. The purpose is to study the initial structure of the wake. A major part of the turbulence in the wake is generated from the shear originated from the difference in air velocity inside and outside the wake. As the velocity deficit determines the shear generated turbulence, the structure and magnitude of the deficit at the rotor is of importance for the development of the wake. Full-scale measurements in a wind farm consisting of four turbines have been performed on the island Gotland, Sweden. For one wind direction the wake at a down wind distance of one diameter can be measured. Comparisons between model and full-scale measurements are presented in this paper, which consists of four parts. First is a section describing the theory for the numerical model. Next section presents the site for the full-scale measurements. In section 3 the numerical results are presented. Finally in section 4 results from full-scale measurements are presented. 12 refs, 23 figs

Magnusson, Mikael [Uppsala Univ. (Sweden). Dept. of Meteorology

1996-03-01

220

Experimental Research for MW Wind Turbine Blade  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this study was get acquiring dependable results of MW wind turbine blade performance at work condition to design new-style blade. Most of the research study on structural analysis of wind turbine blade by make model test and use the finite element, but there were certain differences from real MW wind turbine blade. Therefore full-scale experiments were employed in the research, the strains, stresses and displacements of all parts were gained. The test results shown that the stress distribution was different at every direction and work condition and 12~18 m of the blade is the dangerous area.

Fu Jie; Song Lin-Hui; He Bin; Fan Qin-Shan

2013-01-01

 
 
 
 
221

Basic rotor aerodynamics applied to wind turbines  

Energy Technology Data Exchange (ETDEWEB)

It is the hope of the author that the notes will impart a basic understanding of the mechanisms behind the production of forces on a wind turbine. Even though aero-elastic codes, including a standard Blade Element Momentum method, can be bought, it is considered important that the theory behind this method and its limitations is understood. The aerodynamics of a wind turbine is important, but building a wind turbine is a multi disciplinary task since it requires knowledge of meteorology, atmospheric turbulence, fluid mechanics, structural dynamics, generators, electrical grid connections, gear boxes, hydraulics, foundations, economics and so on. (au) 14 refs.

Hansen, M.O.L.

1998-01-01

222

Dynamic Modeling of Autonomous Wind–Diesel system with Fixed-Speed Wind Turbine  

Directory of Open Access Journals (Sweden)

Full Text Available Wind turbines have often connected to small power systems, operating in parallel to diesel generators, as is typically the case in autonomous wind–diesel installations or small island systems with high wind potential. Hence, the modeling and analysis of the dynamic behavior of wind–diesel power systems in presence of wind power will be important. In this paper, the system under study is modeled by a set of dynamic and algebraic equations (DAE). Dynamic behavior of a wind-diesel system is investigated by the proposed dynamic model. Wind-diesel system consists of wind turbines that are connected to synchronous diesel generator via short transmission line with local load. Dynamic stability of autonomous wind–diesel systems are discussed with emphasis on the eigenvalue analysis and the effective parameters on system stability. In this regards, saddle node bifurcation and hopf bifurcation are also investigated.

Farshad Dastyar; Hamidreza Najafi

2012-01-01

223

Maximum Output Power Tracking of Wind Turbine Using Intelligent Control  

Directory of Open Access Journals (Sweden)

Full Text Available The output power of wind turbine is determined by wind speed. The Output power can be adjusted by controlling the generator speed and pitch angle of wind turbine. When the wind speed below the wind turbine rated, the output power of generator can be maximized by controlling the generator speed at point of maximum power coefficient. When the wind speed above the wind turbine rated, output power of wind turbine will exceed the power generators rated. In this condition, the output power of wind turbine needs to be regulated to conform to the generator power rate. Output power of wind turbine can be regulated by adjusting the pitch angle of wind turbine. In this paper is developed the control strategies based intelligent control for controlling the generator speed and pitch angle of wind turbine, so the maximum output power tracking (MOPT) of wind turbine can be obtained at any wind speed variations. Generator speed is controlled using PI Fuzzy Logic Controller (PI-FLC) based Direct Field Oriented Control (DFOC). Pitch angle of wind turbine is controlled using Elman Recurrent Neural Network (RENN). The simulation results with Matlab Simulink shows that the both controller was successfully regulates the output power when the wind speed above the wind turbine rated and the output power can be maximum when the wind speed below the wind turbine rated.

Muldi Yuhendri; Mochamad Ashari; Mauridhi Hery Purnomo

2011-01-01

224

Maximum Output Power Tracking of Wind Turbine Using Intelligent Control  

Directory of Open Access Journals (Sweden)

Full Text Available The Output power of wind turbine is determined by wind speed. The Output power can be adjusted by controlling the generator speed and pitch angle of wind turbine. When the wind speed below the wind turbine rated, the output power of generator can be maximized by controlling the generator speed at point of maximum power coefficient. When the wind speed above the wind turbine rated, output power of wind turbine will exceed the power generators rated. In this condition, the output power of wind turbine needs to be regulated to conform to the generator power rate. Output power of wind turbine can be regulated by adjusting the pitch angle of wind turbine. In this paper is developed the control strategies based intelligent control for controlling the generator speed and pitch angle of wind turbine, so the maximum output power tracking (MOPT) of wind turbine can be obtained at any wind speed variations. Generator speed is controlled using PI Fuzzy Logic Controller (PI-FLC) based Direct Field Oriented Control (DFOC). Pitch angle of wind turbine is controlled using Elman Recurrent Neural Network (RENN). The simulation results with Matlab Simulink shows that the both controller was successfully regulates the output power when the wind speed above the wind turbine rated and the output power can be maximum when the wind speed below the wind turbine rated.

Muldi Yuhendri; Mochamad Ashari; Mauridhi Hery Purnomo

2011-01-01

225

Structured Control of LPV Systems with Application to Wind Turbines  

DEFF Research Database (Denmark)

This paper deals with structured control of linear parameter varying systems (LPV) with application to wind turbines. Instead of attempting to reduce the problem to linear matrix inequalities (LMI), we propose to design the controllers via an LMI-based iterative algorithm. The proposed algorithm can synthesize structured controllers like decentralized, static output and reduced order output feedback for discrete-time LPV systems. Based on a coordinate decent, it relies on a sufficient matrix inequality condition extended with slack variables to an upper bound on the induced L2-norm of the closed-loop system. Algorithms for the computation of feasible as well as optimal controllers are presented. The general case where no restrictions are imposed on the parameter dependence is treated here due to its suitability for modeling wind turbines. A comprehensive numerical example of a gain-scheduled LPV controller design with prescribed pattern for wind turbines illustrate the utilization of the proposed algorithm.

Adegas, Fabiano Daher; Stoustrup, Jakob

2012-01-01

226

Wind turbines. Fiction and facts; Windmolens. Fictie en feiten  

Energy Technology Data Exchange (ETDEWEB)

The author gives a personal impression of factual and fictional data with respect to different aspects of wind turbines: properties, the production or capacity factor, emission of CO2, the consumption of electricity in the Netherlands, performance, cost price and exploitation costs of wind turbines, environmental effects, government policy, energy yield of 442 wind turbines at 36 sites in the Netherlands, wind turbine projects, and the value of a so-called environmental impact report for wind turbines.

Halkema, J.A.

2000-04-01

227

Forecast and Performance of Wind Turbines  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: Wind energy industry is a nonprofit organization that works hands-on with local and community based wind projects, providing technical support to create an understanding of wind energy opportunities for rural economic benefit. This study provides a detailed vision of the global wind power market and the Indian wind market in particular. It also helps in analyzing and forecasting key metrics relating to the installed capacities, market size and growth. Approach: It helps lay the foundation to build markets for locally owned wind projects in the southeast of Tamil Nadu as well as to help rural landowners and communities benefit more from corporate owned wind projects. As part of this effort, this study organizes state, regional and national wind energy for aimed at moving the wind energy policy and project development dialogue forward, especially regarding community wind projects. Results: This study is designed to give an overview of the wind energy industry and the many benefits and challenges to wind power development in India today. Yet most research in the wind industry remains focused on near term issues, while energy system models that focus on century-long time horizons undervalue wind by imposing exogenous limits on growth. This study fills a critical gap in the literature by taking a closer look at the importance, growth and tariff of large-scale wind. The report helps to comprehend the wind turbine industry and the regulatory framework regarding the wind market in India. It offers interesting results on the market share of the top manufacturers in the India wind turbine industry. Additionally, it also provides the profiles of ten major wind turbine companies in India. Conclusion/Recommendations: This has been an ongoing process to discover the best combination for a given environment in which the wind turbine has to operate and with various challenges met, India would be in a better position to develop and carry forward its own determined initiatives to better the prospects of the wind turbine technology in the coming years. This sectoral innovation systems framework is especially useful tool for analyzing the growth of wind turbine industry and in its essence to preserve the environment with reduction in carbon dioxide emissions.

T. Ahilan; S. Arumugham; R. S. Manimalar

2012-01-01

228

An international perspective on wind turbine noise  

Energy Technology Data Exchange (ETDEWEB)

Established in 1982, the Renewable Energy Systems (RES) Group is a global leader in renewable energy, with a staff of 400 in 15 offices worldwide. The company specializes in the development and construction of wind turbines, biomass facilities, solar energy, geothermal heat pumps and tidal technology. RES currently has 69 wind farm projects underway, with a total capacity of 3,089 MW from approximately 2,000 turbines. When developing a wind turbine array, RES strives to maximize the production of wind-generated electricity from a site while gaining the support of nearby residents. This is accomplished by balancing the interests of developers, society and local residents. The presentation emphasized the importance of having an approach to development that is neither too conservative nor too aggressive. In an effort to resolve difficulties, the United Kingdom has developed a framework for wind farm noise assessment that recommends an allowable wind farm noise limit. figs.

Bass, J. [RES Group (United Kingdom)

2008-07-01

229

Airfoil characteristics for wind turbines  

DEFF Research Database (Denmark)

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 basedon four different methods: 1) Inverse momentum theory, 2) Actuator disc theory, 3) Numerical optimisation and 4) Quasi-3D CFD computations. The two former methods are based on 3D CFD computations and wind tunnel measurements on a 41-m full-scale rotorwith LM 19.1 blades. The derived airfoil characteristics show that the lift coefficient in stall at the tip is low and that it is high at the root compared to 2D airfoil characteristics. The use of these characteristics in aeroelastic calculations shows agood agreement in power and flap moments with measurements. Furthermore, a fatigue analysis shows a reduction in the loads of up to 15 % compared to a commonly used set of airfoil characteristics. The numerical optimisation is based on both the 3D CFDcomputationsand measurements on a 41-m rotor with LM 19.1 and LM 19.0 blades, respectively. The method requires power and loads from a turbine and is promising since a set of lift and drag curves is derived that can be used to calculate mean values ofpower and loads. The lift in stall at the tip is low and at the root it is high compared to 2D airfoil characteristics. In particular the power curves were well calculated by use of the optimised airfoil characteristics. In the quasi-3D CFDcomputations, the airfoil characteristics are derived directly. This Navier-Stokes model takes into account rotational and 3D effects. The model enables the study of the rotational effect of a rotor blade at computing costs similar to what is typical for2D airfoil calculations. The depicted results show that the model is capable of determining the correct qualitative behaviour for airfoils subject to rotation. The method shows that lift is high at the root compared to 2D airfoil characteristics. Thedifferent systematic methods show theimportance of rotational and 3D effects on rotors. Furthermore, the methods show high lift coefficients in stall at the inboard part of the blade and low lift coefficients in stall at the outboard part of the bladecompared to 2D wind tunnel measurements.

Bak, C.; Fuglsang, P.

1999-01-01

230

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

Energy Technology Data Exchange (ETDEWEB)

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

231

Reliability of Wind Turbine Components-Solder Elements Fatigue Failure  

DEFF Research Database (Denmark)

The physics of failure for electrical components due to temperature loading is described. The main focus is on crack propagation in solder joints and damage accumulation models based on the Miner’s rule. Two models are proposed that describe the initial accumulated plastic strain depending on the temperature mean and temperature range. Constant terms and model errors are estimated. The proposed methods are useful to predict damage values for solder joint in power electrical components. Based on the proposed methods it is described how to find the damage level for a given temperature loading profile. The proposed methods are discussed for application in reliability assessment of Wind Turbine’s electrical components considering physical, model and measurement uncertainties. For further research it is proposed to evaluate damage criteria for electrical components due to the operational temperature fluctuations within Wind Turbines

Kostandyan, Erik; SØrensen, John Dalsgaard

2012-01-01

232

Birds and wind turbines: can they co-exist?  

International Nuclear Information System (INIS)

The wind farm is situated along an exposed pier at Blyth Harbour and has now been designated as part of a SSI and part of a proposed RAMSAR site. The bird activity within the harbour is high and is also the wintering home of the Purple Sandpiper. An offshore wind farm is proposed for the area, one kilometre from the pier. Two turbines will be erected with the support of the European Commission THERMIE Programme. The bird study at Blyth has been funded by Border Wind, Blyth Harbour Wind Farm Company and the DTI as part of an ETSU funded study. (UK).

1996-01-01

233

Diffuser for augmenting a wind turbine  

Energy Technology Data Exchange (ETDEWEB)

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); Gilbert, Barry L. (Westbury, NY)

1984-01-01

234

Wind Turbine Drivetrain Condition Monitoring - An Overview  

Energy Technology Data Exchange (ETDEWEB)

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

Sheng, S; Veers, P.

2011-10-01

235

Assessment and prediction of wind turbine noise.  

Science.gov (United States)

The significance of basic aerodynamic noise sources for wind turbine noise are assessed, using information on the aero-acoustic mechanisms of other rotors, which have been studied in depth for many years. From the analysis, areas of potential improvement ...

M. V. Lowson

1993-01-01

236

Review of aerodynamics for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

This article reviews the state of the art of wind turbine rotor aerodynamics. It addresses present uncertainties in rotor design and load calculations, recent modelling efforts to reduce these uncertainties, and validation activities regarding the modelling and results thereof. (author)

Snel, H. [ECN, Petten (Netherlands). Energy Research Centre

2003-07-01

237

Fatigue of fiberglass wind turbine blade materials.  

Science.gov (United States)

Fatigue behavior for a variety of generic materials used in wind turbine blades has been explored. Coupon testing was carried out under constant amplitude tensile fatigue loading to beyond 10(sup 7) cycles for most materials. Unidirectional materials perf...

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

1992-01-01

238

Proceedings: Small Wind Turbine Systems, 1981  

Energy Technology Data Exchange (ETDEWEB)

Small wind turbine technology is discussed. Systems development, test programs, utility interface issues, safety and reliability programs, applications, and marketing are discussed. For individual titles, see N83-23723 through N83-23741.

1981-01-01

239

Microprocessor based control for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

This paper will discuss the design of a microprocessor based control system for a Vertical Axis Wind Turbine (VAWT). A control philosophy is developed and the reasons for a microprocessor control are discussed. 5 refs.

Absi, M.; Dodd, C.

1980-01-01

240

Mobile measurement system for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The aim of this project `Udviklingsafproevning af smaa moellevinger` has been to develop a mobile measurement system for wind turbines. The following report describes the measurement system. The project has been financed by the Danish Ministry of Energy. (au)

Kildemoes Moeller, T.

1997-06-01

 
 
 
 
241

Design prediction model for wind turbine noise  

Energy Technology Data Exchange (ETDEWEB)

A full prediction method for aerodynamic noise from wind turbines suitable for use at the design stage has been developed. The new model involves a sequence of steps: Prediction of Onset Flow, Prediction of Boundary Layer Parameters and Acoustic Prediction. The model provides a basis for the prediction of aerodynamic noise at the initial design stage. It should be noted that the present methods are cumbersome computationally, requiring transfer between a number of different prediction programmes to obtain a final result. Also comparison with experiment is at present very limited, both for basic noise source mechanisms, and for full comparisons with data from actual wind turbines. Nevertheless the new models appear to have potential value to the wind turbine designer to design wind turbines of lower noise with minimal effects of performance. (author)

Lawson, M.V.; Fiddes, S.P. [Flow Solutions Ltd., Bristol (United Kingdom)

1994-12-31

242

Vertical Axis Wind Turbine Foundation parameter study  

Energy Technology Data Exchange (ETDEWEB)

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

243

Available and announced offshore wind turbines  

International Nuclear Information System (INIS)

At the end of 2011, about 4000 MW of offshore wind capacity had been installed in Europe. With market shares of respectively 50% and 40%, Siemens and Vestas are the dominant manufacturers on this market. In the field of offshore wind, Siemens is primarily successful with its wind turbine type SET3,6 (3.6 MW) and Vestas with the V90 of 3.0 MW. The offshore wind turbines of other manufacturers that have a higher capacity do not play a significant role with their market share.

2012-01-01

244

Loads for wind turbines in complex terrain  

Energy Technology Data Exchange (ETDEWEB)

The wind conditions and loads for wind turbines in homogeneous and complex terrain are investigated experimentally and with the use of aeroelastic models. The importance of the differences in wind field parameters for the loads is investigated and we have found that even for complex terrain, the most important load generating parameters is the turbulence intensity. Other differences in wind parameters seem to be of secondary importance for the loads. (author)

Thomsen, Kenneth [Risoe National Lab., Roskilde (Denmark). Test Station for Wind Turbines

1996-12-31

245

Aerodynamical noise from wind turbine generators  

International Nuclear Information System (INIS)

[en] Two extensive measurement series of noise from wind turbines have been made during different modifications of their rotors. One series focused on the influence from the tip shape on the noise, while the other series dealt with the influence from the trailing edge. The experimental layout for the two investigations was identical. The total A-weighted noise from the wind turbine was measured in 1/3 octave bands from 50 Hz to 10 kHz in 1-minute periods simultaneously with wind speed measurements. The microphone was mounted on a hard board on the ground about 40 m directly downwind of the wind turbine, and the wind speed meter was placed at the same distance upwind of the wind turbine 10 m above ground. Regression analysis was made between noise and wind speed in each 1/3 octave band to determine the spectrum at 8 m/s. During the measurements care was taken to avoid influence from background noise, and the influence from machinery noise was minimized and corrected for. Thus the results display the aerodynamic rotor noise from the wind turbines. By use of this measurement technique, the uncertainty has been reduced to 1.5 - 2 dB per 1/3 octave band in the relevant frequency range and to about 1 dB on the total A-weighted levels. (au) (10 refs.)

1993-01-01

246

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

Energy Technology Data Exchange (ETDEWEB)

This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers to wind energy expansion by providing independent testing results for small wind turbines (SWT). In total, five turbines were tested at the National Wind Technology Center (NWTC) as a part of this project. Safety and function testing is one of up to five tests performed on the turbines, including power performance, duration, noise, and power-quality tests. NWTC testing results provide manufacturers with reports that may be used to meet part of small wind turbine certification requirements. The test equipment includes a Mariah Windspire wind turbine mounted on a monopole tower. L&E Machine manufactured the turbine in the United States. The inverter was manufactured separately by Technology Driven Products in the United States. The system was installed by the NWTC site operations group with guidance and assistance from Mariah Power.

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

2010-07-01

247

Modeling stochastic wind loads on vertical axis wind turbines  

Science.gov (United States)

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.

248

Passively cooled direct drive wind turbine  

Science.gov (United States)

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

249

Method for lubricating wind turbine gearbox  

UK PubMed Central (United Kingdom)

A method of lubricating a wind turbine gearbox comprising using a lubricating composition comprising at least one (i.e. one or a mixture of more than one) perfluoropolyether (PFPE) lubricant which comprises a perfluorooxyalkylene chain, said perfluorooxyalkylene chain comprising recurring units having at least one ether bond and at least one fluorocarbon moiety. A wind turbine gearbox comprising a lubricating system containing said lubricating composition.

BOCCALETTI GIOVANNI; RIGANTI FABIO; JUNGK MANFRED

250

Assessment of wind turbine load measurement instrumentation  

Energy Technology Data Exchange (ETDEWEB)

In the framework of Sub-Task3 `Wind turbine load measurement instrumentation` of EU-project `European Wind Turbine Testing Procedure Development`, the load measurement techniques have been assessed by laboratory, full scale and numerical tests. The existing methods have been reviewed with emphasis on the strain gage application techniques on composite materials and recommendations are provided for the optimisation of load measurement techniques. (au) EU. 14 refs.

Morfiadakis, E.; Papadopoulos, K. [CRES (Greece); Borg, N. van der [ECN, Petten (Netherlands); Petersen, S.M. [Risoe, Roskilde (Denmark); Seifert, H. [DEWI, Wilhelmshaven (Germany)

1999-03-01

251

Reliability-Based Optimization of Wind Turbines  

DEFF Research Database (Denmark)

Reliability-based optimization of the main tower and monopile foundation of an offshore wind turbine is considered. Different formulations are considered of the objective function including benefits and building and failure costs of the wind turbine. Also different reconstruction policies in case of failure are considered, including systematic reconstruction and failure of the control system. An example is presented, and as a part of the result the optimal reliability level is obtained.

SØrensen, John Dalsgaard; Tarp-Johansen, N.J.

2004-01-01

252

Site-optimization of wind turbine generators  

Energy Technology Data Exchange (ETDEWEB)

The Danish Company Nordtank is one of the pioneers within the wind turbine industry. Since 1981 Nordtank has installed worldwide more than 2500 wind turbine generators with a total name plate capacity that is exceeding 450 MW. The opening up of new and widely divergent markets has demanded an extremely flexible approach towards wind turbine construction. The Nordtank product range has expanded considerable in recent years, with the main objective to develop wind energy conversion machines that can run profitable in any given case. This paper will describe site optimization of Nordtank wind turbines. Nordtank has developed a flexible design concept for its WTGs in the 500/750 kW range, in order to offer the optimal WTG solution for any given site and wind regime. Through this flexible design, the 500/750 turbine line can adjust the rotor diameter, tower height and many other components to optimally fit the turbine to each specific project. This design philosophy will be illustrated with some case histories of recently completed projects.

Wolff, T.J. de; Thillerup, J. [Nordtank Energy Group, Richmond, VA (United States)

1997-12-31

253

Adaptive Extremum Control and Wind Turbine Control  

DEFF Research Database (Denmark)

This thesis is divided into two parts, i.e., adaptive extremum control and modelling and control of a wind turbine. The rst part of the thesis deals with the design of adaptive extremum controllers for some processes which have the behaviour that process should have as high e ciency as possible. Firstly, it is assumed that the nonlinear processes can be divided into a dynamic linear part and static nonlinear part. Consequently the processes with input nonlinearity and output nonlinearity are treated separately. With the nonlinearity at the input it is easy to set up a model which is linear in parameters, and thus directly lends itself to parameter estimation and adaptive control. The extremum control law is derived based on static optimization of a performance function. For a process with nonlinearity at output the intermediate signal between the linear part and nonlinear part plays an important role. If it can be emphasis on control design. The models have beenvalidated by experimental data obtained from an existing wind turbine. The e ective wind speed experienced by the rotor of a wind turbine, which is often required by some control methods, is estimated by using a wind turbine as a wind measuring device. The investigation of control design is divided into below rated operation and above rated operation. Below ratedpower, the aim of control is to extract maximumenergy from the wind. The pitch angle of the rotor blades is xed at its optimal value and turbine speed is adjusted to follow thechanges in wind speed. Above rated power, the control design problem is to limit and smooth the output electrical power. The pitch control is investigated for both constant speed and variable speed wind turbines. The minimization of the turbine transient loads is focussed in both cases.

Ma, Xin

1997-01-01

254

Laboratory implementation of variable-speed wind turbine generation  

Energy Technology Data Exchange (ETDEWEB)

To improve the performance of wind turbines, various control schemes such as variable speed operation have been proposed. Testing of these control algorithms on a full scale system is very expensive. To test these systems simulation, we developed programs and small scale laboratory experiments. We used this system to verify a control method that attempts to keep the turbine operating at its peak power coefficient. Both the simulations and the experiments verified the principle of operation of this control scheme.

Zinger, D.S. [Northern Illinois University, DeKalb, IL (United States); Miller, A.A. [Univ. of Idaho, Moscow, ID (United States); Muljadi, E.; Butterfield, C.P.; Robinson, M.C. [National Renewable Energy Lab., Golden, CO (United States)

1996-07-01

255

Cost optimization of wind turbines for large-scale offshore wind farms  

International Nuclear Information System (INIS)

[en] This report contains a preliminary investigation of site specific design of off-shore wind turbines for a large off-shore wind farm project at Roedsand that is currently being proposed by ELKRAFT/SEAS. The results were found using a design tool for wind turbines that involve numerical optimization and aeroelastic calculations of response. The wind climate was modeled in detail and a cost function was used to estimate costs from manufacture and installation. Cost of energy is higher for off-shore installations. A comparison of an off-shore wind farm site with a typical stand alone on-shore site showed an increase of the annual production of 28% due to the difference in wind climate. Extreme loads and blade fatigue loads were nearly identical, however,fatigue loads on other main components increased significantly. Optimizations were carried out to find the optimum overall off-shore wind turbine design. A wind turbine for the off-shore wind farm should be different compared with a stand-alone on-shore wind turbine. The overall design changed were increased swept area and rated power combined with reduced rotor speed and tower height. Cost was reduced by 12% for the final 5D/14D off-shore wind turbine from 0.306 DKr/kWh to 0.270 DKr/kWh. These figures include capital costs from manufacture and installation but not on-going costs from maintenance. These results make off-shore wind farms more competitive and comparable to the reference on-shore stand-alone wind turbine. A corresponding reduction of cost of energy could not be found for the stand alone on-shore wind turbine. Furthermore the fatigue loads on wind turbines in on-shore wind farms will increase and cost of energy will increase in favor of off-shore wind farms. (au) EFP-95; EU-JOULE-3; 21 tabs., 7 ills., 8 refs

1998-01-01

256

Power electronics for modern wind turbines  

CERN Document Server

Wind energy is now the world's fastest growing energy source. In the past 10 years, the global wind energy capacity has increased rapidly. The installed global wind power capacity has grown to 47.317 GW from about 3.5 GW in 1994. The global wind power industry installed 7976 MW in 2004, an increase in total installed generating capacity of 20%. The phenomenal growth in the wind energy industry can be attributed to the concerns to the environmental issues, and research and development of innovative cost-reducing technologies.Denmark is a leading producer of wind turbines in the world, with an a

Blaabjerg, Frede

2006-01-01

257

Innovative multi rotor wind turbine designs  

Energy Technology Data Exchange (ETDEWEB)

Among the renewable energy sources, today wind energy is the most recognized and cost effective. Developers and researchers in this sector are optimistic and continuously working innovatively to improve the technology. The wind power obtained is proportional to the swept area of wind turbine. The swept area is increased by using a single rotor of large diameter or multi rotors in array. The rotor size is growing continuously with mature technology. Multi rotor technology has a long history and the multi rotor concept persists in a variety of modern innovative systems but the concept has fallen out of consideration in mainstream design from the perception that is complex and unnecessary as very large single rotor units are now technically feasible. This work addresses the evaluation of different multi rotor wind turbine systems. These innovative wind turbines are evaluated on the basis of feasibility, technological advantages, security of expected power performance, cost, reliability, impact of innovative system, comparison with existing wind turbine design. The findings of this work will provide guidelines for the practical and economical ways for further research on the multi rotor wind turbines. (Author)

Kale, S.A.; Sapali, S.N. [College of Engineering. Mechanical Engineering Dept, Pune (India)

2012-07-01

258

Computational study and modeling of turbine spacing effects in infinite aligned wind farms  

Science.gov (United States)

We study the turbine spacing effects in infinite, aligned wind-turbine arrays using large-eddy simulation (LES) with the wind turbine rotors parameterized as actuator disks. A series of simulations is carried out to systematically investigate the different effects of streamwise and spanwise turbine spacings on the array power output and turbulence intensities. We show that for the same turbine density, increasing the streamwise spacing is more beneficial than increasing the spanwise spacing. Larger streamwise turbine spacing increases the power extraction and lowers the turbulence intensity at each turbine more efficiently than when the spanwise turbine spacing is increased. The reason for the different effects of streamwise and spanwise turbine spacings on wind farm performance is that the wake recovery of wind turbines in infinite arrays depends on the area influenced by the wind-turbine wakes, rather than the land area occupied by each turbine. Based on this idea, an improved effective roughness height model is proposed, which can account for the different effects of streamwise and spanwise turbine spacings in infinite aligned wind farms. The predictive capabilities of the new model are demonstrated via extensive comparisons with results obtained from the LES and previously proposed roughness height models.

Yang, Xiaolei; Kang, Seokkoo; Sotiropoulos, Fotis

2012-11-01

259

Design Oriented Aerodynamic Modelling of Wind Turbine Performance  

International Nuclear Information System (INIS)

[en] The development of a wind turbine aerodynamics model using a Boundary Integral Equation model (BIEM) is presented. The methodology is valid to study inviscid unsteady flows around three dimensional bodies of arbitrary shape and arbitrarily moving with respect to the incoming flow. The extension of this methodology to study viscosity effects in turbine blade flow at high angle of attack is addressed and an approach to determine aerodynamic loads over a wide range of turbine operating conditions is proposed. Numerical applications considering a selected test cases from the NREL experimental dataset are presented. Finally, the application of the proposed turbine aerodynamics model into a multi-disciplinary study including aeroelasticity of pylon-turbine assembly and aeroacoustics modelling of induced noise is briefly described

2007-01-01

260

Load prediction of stall regulated wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Measurements of blade loads on a turbine situated in a small wind farm shows that the highest blade loads occur during operation close to the peak power i.e. when the turbine operates in the stall region. In this study the extensive experimental data base has been utilised to compare loads in selected campaigns with corresponding load predictions. The predictions are based on time domain simulations of the wind turbine structure, performed by the aeroelastic code VIDYN. In the calculations a model were adopted in order to include the effects of dynamic stall. This paper describes the work carried out so far within the project and key results. 5 refs, 10 figs

Bjoerck, A.; Dahlberg, J.Aa. [Aeronautical Research Inst. of Sweden, Bromma (Sweden); Carlen, I. [Chalmers Univ. of Technology, Goeteborg (Sweden). Div. of Marine Structural Engineering; Ganander, H. [Teknikgruppen AB, Sollentua (Sweden)

1996-12-01

 
 
 
 
261

The social acceptability of wind turbines: some resident are ready to pay to keep their wind turbines. Survey on four French wind farms  

International Nuclear Information System (INIS)

The authors report a study which aimed at exploiting and deepening the results of a 2001 survey on visual and sound disturbances caused by wind turbines in Sigean (Aude), at identifying all the attitudes and opinions with respect with wind energy, and at assessing the different characteristics of a wind farm (height, localization, and so on). A survey has been performed on four sites located in different French regions. The authors discuss the social-demographic characteristics of the population samples, the global opinion on wind energy, and the opinion of the people on wind turbines located in their neighbourhood. They propose an estimation of benefits and damages related to the vicinity of wind turbines. By applying a method of choice experiments, they reveal the preferences of residents

2009-01-01

262

Predicted aerodynamic performance of a horizontal-axis wind turbine equipped with vortex generators  

Energy Technology Data Exchange (ETDEWEB)

A simple flow model for a wind turbine with vortex generators on the blades is developed and applied to an existing wind turbine geometry. The performance of the proposed flow model is evaluated by contrasting the results of the numerical work with available experimental data. The possibility of improving wind turbine efficiency by incorporating vortex generators on rotor blades is demonstrated. 13 figs., 20 refs.

Afjeh, A.A.; Keith, T.G.; Fateh, A. (Toledo Univ., OH (USA) Eldec Corp., Seattle, WA (USA))

1990-04-01

263

Tribological advancements for reliable wind turbine performance.  

UK PubMed Central (United Kingdom)

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.

Kotzalas MN; Doll GL

2010-10-01

264

Tribological advancements for reliable wind turbine performance.  

Science.gov (United States)

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

265

Jet spoiler arrangement for wind turbine  

Energy Technology Data Exchange (ETDEWEB)

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); Kadlec, Emil G. (Albuquerque, NM); Klimas, Paul C. (Albuquerque, NM)

1985-01-01

266

The BONUS 750kw wind turbine  

Energy Technology Data Exchange (ETDEWEB)

The development of the BONUS 750 kW wind turbine commenced in 1993 with support by a JOULE II grant. The general purpose of the project was the development of a competitive large wind turbine in the 50 m range. It was argued that the highest probability of success would be achieved through the combination of new, competitive technology with proven and reliable concepts. Based on the traditional ``Danish concept`` the new turbine would use novel design features in the aerodynamics and the structural dynamics. The expected achievement of the project was a reduction in the energy price of 25% compared with the Danish turbines being marketed at that time. The prototype turbine was erected in September 1994 at Tjaereborg, Denmark and was put into automatic operation early 1995. The performance and noise levels were satisfactory, and the primary cost reduction goal has been met. (author)

Stiesdal, H. [BONUS Energy A/S, Brande (Denmark)

1996-12-31

267

Environmental life cycle analyses of wind turbines  

International Nuclear Information System (INIS)

The aim of this investigation is to determine environmental aspects of (1) upscaling of both onshore and offshore turbines and (2) offshore versus onshore placement of turbines. Attention has also been paid to a couple of waste processing options in order to obtain a responsible disposal of dismissed wing blades of wind turbines. Shortcomings of the followed procedure for life cycle assessments are pinpointed in the field of the software package, the inventory and the normalization of effect scores both for classification and evaluation. Upscaling from a 300 kW wind turbine to a 500 kW wind turbine results in a decrease (20-50%) of all environmental impacts considered in this study both for an onshore and an offshore situation. This is caused by the fact that the increase of materials use turns out to be lower than the increase in energy production. However, smaller differences than assumed in this study in electricity production between the two types of wind turbines - depending on wind climate and design - will result in a lower decrease or even an increase in environmental impacts. Offshore placement leads to considerably higher environmental impacts compared to onshore placement (5-180%). However, offshore placement offers important advantages in the field of noise pollution, adverse effect on landscape and level of electricity production. 11 figs., 25 tabs., 41 refs.

1996-01-01

268

Acoustic Tests of Small Wind Turbines: Preprint  

Energy Technology Data Exchange (ETDEWEB)

Eight small wind turbines ranging from 400 watts to 100 kW in rated power were tested for acoustic emissions at the U.S. Department of Energy's National Renewable Energy Laboratory. Rigorous test procedures based on international standards were followed for measurements and data analyses. Results are presented in the form of sound pressure level versus wind speed, where the sound was recorded downwind of the turbine at a distance equal to the hub height plus half the rotor diameter. When there was sufficient separation between wind turbine noise and background noise, the apparent sound power level was calculated. In several cases, this was not possible. The implications of this problem are discussed briefly. Some of the configurations tested were specifically developed to reduce the noise level of their predecessors. Test data for these machines demonstrate marked progress toward quieter turbines.

Migliore, P.; van Dam, J.; Huskey, A.

2003-10-01

269

Vertical axis wind turbine control strategy  

Energy Technology Data Exchange (ETDEWEB)

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

270

RELIABILITY OF MACHINE ELEMENTS IN WIND TURBINES  

Directory of Open Access Journals (Sweden)

Full Text Available Worldwide electrical energy production generated by wind turbines grows at a rate of 30 percent. This doubles the total production every three years. At the same time the power of individual stations goes up by 20 percent annually. Whereas today the towers, rotors and drive trains have to handle 5 MW, in about six to eight years they might produce up to fifteen MW. As a consequence, enormous pressure is put on the wind turbine manufacturers, the component suppliers and the operators. And because prototype and field testing is limited by its expense, the design of new turbines demands thorough analysis and simulation. Looking at the critical components of a wind turbine this paper describes advanced design tools which help to anticipate failures, but also assists in optimizing reliability and service life. Development of the software tools has been supported by research activities in many universities.

Willi GRUENDER

2010-01-01

271

Voltage Regulation of Variable Speed Wind Turbine using MATLAB/Simulink  

Directory of Open Access Journals (Sweden)

Full Text Available The conventional sources of energy are depleting and emphasis is now focused on renewable energy. Wind energy is one of the renewable sources having great potential. It is cheap and requires less maintenance but also have issues associated with it. The main issue associated with Wind turbines (WT) is the unpredictable nature of wind. This makes it difficult to get a constant frequency and constant voltage from wind turbines driven by the variable speed. This paper presents method of regulating the output voltage for standalone wind turbine driven by variable speed wind. The method is based on the using voltage regulator for the fluctuating voltage of wind turbine driven by variable speed. The regulated voltage is supplied to utility. Battery system is also proposed for the system which will provide power when wind regulated voltage is dropped from a threshold value due to low wind speed or absence of wind.

Arshad Nawaz; Muhammad Naeem Arbab

2013-01-01

272

Fatigue analysis of offshore wind turbine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this master thesis analyses will be conducted on a 5MW offshore wind turbine, with a jacket foundation. The goal is to investigate how seven different wind profiles affect fatigue in the blade root, the tower top and the tower bottom. The effect of the turbulence level is also investigated. The a...

Stava, Ole Magnus

273

Tailored airfoils for vertical axis wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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 that significant reductions in system costs-of-energy and increases in fatigue lifetime may be expected for VAWT systems using these blade elements.

Klimas, P.C.

1984-11-01

274

Tailored airfoils for vertical axis wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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 that significant reductions in system costs-of-energy and increases in fatigue lifetime may be expected for VAWT systems using these blade elements.

Klimas, P.C.

1984-01-01

275

Tailored airfoils for Vertical Axis Wind Turbines*  

Energy Technology Data Exchange (ETDEWEB)

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 that significant reductions in system cost-ofenergy and increases in fatigue lifetime may be expected for VAWT systems using these blade elements.

Klimas, P.C.

1984-08-01

276

A wind turbine evaluation model under a multi-criteria decision making environment  

International Nuclear Information System (INIS)

[en] Highlights: ? This paper proposes an evaluation model to select suitable turbines in a wind farm. ? Interpretive structural modeling is used to know the relationship among factors. ? Fuzzy analytic network process is used to calculate the priorities of turbines. ? The results can be references for selecting the most appropriate wind turbines. - Abstract: Due to the impacts of fossil and nuclear energy on the security, economics, and environment in the world, the demand of alternative energy resources is expanding consistently and tremendously in recent years. Wind energy production, with its safe and environmental characteristics, has become the fastest growing renewable energy source in the world. The construction of new wind farms and the installation of new wind turbines are important processes in order to provide a long-term energy production. In this research, a comprehensive evaluation model, which incorporates interpretive structural modeling (ISM) and fuzzy analytic network process (FANP), is constructed to select suitable turbines when developing a wind farm. A case study is carried out in Taiwan in evaluating the expected performance of several potential types of wind turbines, and experts in a wind farm are invited to contribute their expertise in determining the importance of the factors of the wind turbine evaluation and in rating the performance of the turbines with respect to each factor. The most suitable turbines for installation can finally be generated after the calculations. The results can be references for decision makers in selecting the most appropriate wind turbines.

2012-01-01

277

Study on optimal design of wind turbine blade airfoil and its application  

International Nuclear Information System (INIS)

[en] This study was carried out with two goals. One was the development of a model of a wind turbine blade airfoil and the other was the application of the folding blade. In general, in large sized (MW) wind turbines, damage is prevented in small wind turbines since equipment costs and maintenance costs are high, and therefore, the blade will cause serious damage. The wind turbine proposed in this study does not require maintenance, and the blades do not break during high winds because they are folded in accordance with changes in the wind speed. But generators are not cut out, while maintaining a constant angle will continue to produce. The focus of this study, the wind turbine is continued by folding blade system in strong winds and gusts without stopping production

2012-01-01

278

Design optimization of a cost-effective micro wind turbine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this paper is to investigate the performance of a specially designed micro wind turbine for urban environment where the wind speed is usually low. Differing from the traditional wind turbine that can be connected directly to the grid, the micro wind turbine is linked to a small generator ...

Leung, DYC; Deng, Y; Leung, MKH

279

Structural Reliability Aspects in Design of Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Reliability assessment, optimal design and optimal operation and maintenance of wind turbines are an area of significant interest for the fast growing wind turbine industry for sustainable production of energy. Offshore wind turbines in wind farms give special problems due to wake effects inside the...

Sørensen, John Dalsgaard

280

A neuro-fuzzy controlling algorithm for wind turbine  

Energy Technology Data Exchange (ETDEWEB)

The wind turbine control system is stochastic and nonlinear, offering a demanding field for different control methods. An improved and efficient controller will have great impact on the cost-effectiveness of the technology. In this article, a design method for a self-organizing fuzzy controller is discussed, which combines two popular computational intelligence techniques, neural networks and fuzzy logic. Based on acquisited dynamic parameters of the wind, it can effectively predict wind changes in speed and direction. Maximum power can always be extracted from the kinetic energy of the wind. Based on the stimulating experiments applying nonlinear dynamics to a `Variable Speed Fixed Angle` wind turbine, it is demonstrated that the proposed control model 3rd learning algorithm provide a predictable, stable and accurate performance. The robustness of the controller to system parameter variations and measurement disturbances is also discussed. (author)

Li Lin [Tampere Univ. of Technology (Finland); Eriksson, J.T. [Tampere Univ. of Technology (Finland)

1995-12-31

 
 
 
 
281

Vortex system studies on small wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The wind tunnel experiment reported included a small wind turbine setup and smoke to visualize the trailing tip vortices for different wind turbine configurations. Several combinations of tunnel wind speeds and tip speed ratios generated a database where the end result functions were radius and pitch, of the tip vortex spirals, versus the downstream coordinate. The Reynolds number in the experiment was very low compared to that of full size turbines. The results should therefore be seen as valid only for low Reynolds numbers. The models were 18 and 25 cm diameter turbines. This is thought to be complementary to the information obtained in similar wind tunnel investigations for much larger models. The database is meant to be a fundamental tool for the construction of practical aerodynamic induction methods. Such methods typically employ the Biot-Savart law has been shown to lead to a flow field, which deviates considerably from that of reality. E.g. concentration into tip vortices does not happen when the flow is simulated with Biot-Savart law only. Thus, a combination of the induction method and its modification, based on investigations such as the one reported, is foreseen to replace the widely used Blade Element Momentum method for wind turbine loads and performance prediction.

Montgomerie, Bjoern; Dahlberg, Jan-Aake [Swedish Defence Research Agency, Stockholm (Sweden). Div. of Aeronautics, FFA

2003-10-01

282

Review paper on wind turbine aerodynamics  

DEFF Research Database (Denmark)

The paper describes the development and description of the aerodynamic models used to estimate the aerodynamic loads on wind turbine constructions. This includes a status of the capabilities of computation fluid dynamics and the need for reliable airfoil data for the simpler engineering models. Also a discussion of the use of passive and active aerodynamic devices is included such as, e.g., Vortex Generators and distributed active flaps. Finally the problem of wakes in wind farms is addressed and a section of the likely future development of aerodynamic models for wind turbines is included. © 2011 American Society of Mechanical Engineers.

Hansen, Martin Otto Laver; Aagaard Madsen, Helge

2011-01-01

283

Fatigue Reliability of Offshore Wind Turbine Systems  

DEFF Research Database (Denmark)

Optimization of the design of offshore wind turbine substructures with respect to fatigue loads is an important issue in offshore wind energy. A stochastic model is developed for assessing the fatigue failure reliability. This model can be used for direct probabilistic design and for calibration of appropriate partial safety factors / fatigue design factors (FDF) for steel substructures of offshore wind turbines (OWTs). The fatigue life is modeled by the SN approach. Design and limit state equations are established based on the accumulated fatigue damage. The acceptable reliability level for optimal fatigue design of OWTs is discussed and results for reliability assessment of typical fatigue critical design of offshore steel support structures are presented.

Marquez-Dominguez, Sergio; SØrensen, John Dalsgaard

2012-01-01

284

The design of wind turbine for electrical power generation in Malaysian wind characteristics  

International Nuclear Information System (INIS)

[en] The paper describes the study of a wind turbine for electrical power generation in Malaysia wind characteristics. In this research, the wind turbine is designs based on the local wind characteristics and tries to avoid the problems faced in the past (turbine design, access, manpower and technical). The new wind turbine rotor design for a medium speed wind speed turbine utilises the concept of open-close type of horizontal axis (up-wind) wind turbine is intended to widen the optimum performance range for electrical generation in Malaysia wind characteristics. The wind turbine has been designed to cut-in at a lower speed, and to provide the rotation speed that high enough to run a generator. The analysis and design of new low speed wind turbine blades and open-close turbine rotor and prediction of turbine performance are being detailed in this paper. (Author)

2000-01-01

285

Parametric evaluation of wind turbine noise  

Energy Technology Data Exchange (ETDEWEB)

In lieu of large single wind turbine installations, US Windpower, Burlington, Massachusetts is promoting the wind farm concept for wind power generation. A wind farm is an array of several small machines which are used to produce the equipment power of a single, large wind turbine. The smaller 50 KW machines manufactured by US Windpower, when used in an array to produce a large quantity of power, minimize the incidence of annoying infrasonic pulsing, nevertheless, the production of low frequency sound by wind farms still occurs. Measurements and theory clearly demonstrate that blade passage through the tower wake produces a sound pressure level frequency spectra consisting of harmonics of the blade passage frequency. The chief purpose of this work is to identify the importance of various tower and blade parameters that control blade passage noise generation.

Tocci, G.C.; Marcus, E.N.

1982-01-01

286

Design of the Wind Eagle Turbine  

Energy Technology Data Exchange (ETDEWEB)

The Wind Eagle Turbine has many design features that contribute to a simple, lightweight, low cost and rugged wind machine. It is a down wind, two bladed, rigid hub, free yaw and free pitch machine with full span blade pitch control. Most of the wind community are unaware of the advantages that are inherent in the Wind Eagle concept. It is the intent of this oral presentation to point out and discuss the features of this design so there is a better understanding of this very cost effective machine. Some parts of the Wind Eagle Turbine to be covered include: main spar, spar and blade connection, fiberglass blade, yaw bearing, tower, low speed shaft and shut down.

Carter, J. Sr. [Wind Eagle Corporation, Wichita Falls, TX (United States).

1995-09-01

287

Robust Utilization of Wind Turbine Flexibility for Grid Stabilization  

DEFF Research Database (Denmark)

This work considers the use of wind turbines for stabilizing an electrical grid, by employing temporary overproduction with respect to available power. We present a simple model describing a turbine, and show how the possible period of overproduction, can be maximized through a series of convex problems, where the load is distributed among several turbines in a farm. We then present an optimization scheme that guarantees a lower limit for the overproduction period and subsequently propose an adaptive implementation that is robust against parameter uncertainties.

Juelsgaard, Morten; Bendtsen, Jan Dimon

2012-01-01

288

H? Based Control for Load Mitigation in Wind Turbines  

Directory of Open Access Journals (Sweden)

Full Text Available This article demonstrates a strategy to design multivariable and multi-objective controllers based on the H? norm reduction applied to a wind turbine. The wind turbine model has been developed in the GH Bladed software and it is based on a 5 MW wind turbine defined in the Upwind European project. The designed control strategy works in the above rated power production zone and performs generator speed control and load reduction on the drive train and tower. In order to do this, two robust H? MISO (Multi-Input Single-Output) controllers have been developed. These controllers generate collective pitch angle and generator torque set-point values to achieve the imposed control objectives. Linear models obtained in GH Bladed 4.0 are used, but the control design methodology can be used with linear models obtained from any other modelling package. Controllers are designed by setting out a mixed sensitivity problem, where some notch filters are also included in the controller dynamics. The obtained H? controllers have been validated in GH Bladed and an exhaustive analysis has been carried out to calculate fatigue load reduction on wind turbine components, as well as to analyze load mitigation in some extreme cases. The analysis compares the proposed control strategy based on H? controllers to a baseline control strategy designed using the classical control methods implemented on the present wind turbines.

Asier Diaz de Corcuera; Aron Pujana-Arrese; Jose M. Ezquerra; Edurne Segurola; Joseba Landaluze

2012-01-01

289

Grid impact of variable-speed wind turbines  

Energy Technology Data Exchange (ETDEWEB)

In this paper the power quality of variable-speed wind turbines equipped with forced-commutated inverters is investigated. Measurements have been taken on the same type of variable-speed wind turbines in Germany and Sweden. The measurements have been analysed according to existing IEC standards. Special attention has been paid to the aggregation of several wind turbines on flicker emission and harmonics. The aggregation has been compared with the summation laws used in the draft IEC 61400-21 `Power Quality Requirements for Grid Connected wind turbines`. The methods for calculating and summing flicker proposed by IEC Standards are reliable. Harmonics and inter-harmonics are treated in IEC 61000-4-7 and IEC 61000-3-6. The methods for summing harmonics and inter-harmonics in IEC 61000-3-6 are applicable to wind turbines. In order to obtain a correct magnitude of the frequency components, the use of a well-defined window width, according to IEC 61000-4-7 Amendment 1 is of a great importance. (au)

Larsson, Aa. [Chalmers Univ. of Technology, Dept. of Electric Power Engineering, Goeteborg (Sweden); Soerensen, P. [Risoe National Lab., Roskilde (Denmark); Santjer, F. [German Wind Energy Inst., DEWI, Wilhelmshaven (Germany)

1999-03-01

290

Distribution of extreme gust loads of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Extreme gust loading of wind turbines has been treated deterministically as prescribed in the design codes, without taking into account the stochastic property of the wind turbulence. In this paper a rational approach to quantify the variability of the gust loading of a wind turbine is presented and a new approach on the simulation of the extreme gusts with constrained simulations is proposed. The results from simulations with deterministic gusts and stochastic gusts are compared. The distribution of the extreme response due to extreme gust is derived using the constrained gust approach. The influence on response of a spatial gust and a point gust is studied. The effect of the gust centre on the turbine response has also been taken into account. The response distribution at a certain mean wind speed is determined with full-scale time domain simulation and compared to the distribution derived with constrained gusts. The method is demonstrated using the turbine model of a prototype wind turbine; for this reason the result is preliminary and generalization should be made with care.

Cheng, P.W.; Bierbooms, W.A.A.M. [Institute for Wind Energy, TU Delft, Stevinweg 1, 2628 CN Delft (Netherlands)

2001-03-01

291

Failure Probability Estimation of Wind Turbines by Enhanced Monte Carlo  

DEFF Research Database (Denmark)

This paper discusses the estimation of the failure probability of wind turbines required by codes of practice for designing them. The Standard Monte Carlo (SMC) simulations may be used for this reason conceptually as an alternative to the popular Peaks-Over-Threshold (POT) method. However, estimation of very low failure probabilities with SMC simulations leads to unacceptably high computational costs. In this study, an Enhanced Monte Carlo (EMC) method is proposed that overcomes this obstacle. The method has advantages over both POT and SMC in terms of its low computational cost and accuracy. The method is applied to a low-order numerical model of a 5 MW wind turbine with a pitch controller exposed to a turbulent inflow. Two cases of the wind turbine model are investigated. In the first case, the rotor is running with a constant rotational speed. In the second case, the variable rotational speed is controlled by the pitch controller. This provides a fair framework for comparison of the behavior and failure event of the wind turbine with emphasis on the effect of the pitch controller. The Enhanced Monte Carlo method is then applied to the model and the failure probabilities of the model are estimated to the values related to the required 50-year return period of the wind turbine.

Sichani, Mahdi Teimouri; Nielsen, SØren R.K.

2012-01-01

292

Observer Backstepping Control for Variable Speed Wind Turbine  

DEFF Research Database (Denmark)

This paper presents an observer backstepping controller as feasible solution to variable speed control of wind turbines to maximize wind power capture when operating between cut-in and rated wind speeds. The wind turbine is modeled as a two-mass drive-train system controlled by the generator torque. The nonlinear controller aims at regulating the generator torque such that an optimal tip-speed ratio can be obtained. Simply relying on the measured rotor angular velocity the proposed observer backstepping controller guarantees global asymptotic tracking of the desired trajectory while maintaining a globally uniformly ultimately bounded torsional angle. The proposed controller shows convincing performance when simulated in closed loop within a stochastic environment.

Galeazzi, Roberto; Gryning, Mikkel Peter Sidoroff

2013-01-01

293

Wind Turbine Micropitting Workshop: A Recap  

Energy Technology Data Exchange (ETDEWEB)

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

Sheng, S.

2010-02-01

294

A review of wind turbine noise  

Energy Technology Data Exchange (ETDEWEB)

The IEC standard 61400-11 wind turbines - Part 11 'acoustic noise measurement techniques' was revised recently in order to present a procedure expected to provide accurate results that can be replicated by others. Immission measurements are not within the scope of this IEC standard. The different measurement procedures of noise immission from wind turbines at noise receptor locations are described in an IEA recommendation. In this general review the history and the state of the art of wind turbine noise is given with special emphasis on: noise sources, propagation effects, standards and recommendations, noise reduction, measurement procedures at high wind speeds, noise characteristics (e.g. tonality) and declaration and verification of sound levels. (orig.)

Klug, H. [DEWI Wilhelmshaven (Germany)

2006-08-15

295

Computer control for remote wind turbine operation  

Energy Technology Data Exchange (ETDEWEB)

Light weight wind turbines located in harsh, remote sites require particularly capable controllers. Based on extensive operation of the original ESI-807 moved to such a location, a much more sophisticated controller than the original one has been developed. This paper describes the design, development and testing of that new controller. The complete control and monitoring system consists of sensor and control inputs, the control computer, control outputs, and additional equipment. The control code was written in Microsoft Visual Basic on a PC type computer. The control code monitors potential faults and allows the turbine to operate in one of eight states: off, start, run, freewheel, low wind shut down, normal wind shutdown, emergency shutdown, and blade parking. The controller also incorporates two {open_quotes}virtual wind turbines,{close_quotes} including a dynamic model of the machine, for code testing. The controller can handle numerous situations for which the original controller was unequipped.

Manwell, J.F.; Rogers, A.L.; Abdulwahid, U.; Driscoll, J. [Univ. of Massachusetts, Amherst, MA (United States)

1997-12-31

296

Load attenuating passively adaptive wind turbine blade  

Energy Technology Data Exchange (ETDEWEB)

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

297

A Shrouded Wind Turbine Generating High Output Power with Wind-lens Technology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have developed a new wind turbine system that consists of a diffuser shroud with a broad-ring brim at the exit periphery and a wind turbine inside it. The shrouded wind turbine with a brimmed diffuser has demonstrated power augmentation by a factor of about 2–5 compared with a bare wind turbine, ...

Yuji Ohya; Takashi Karasudani

298

Defect distribution and reliability assessment of wind turbine blades  

DEFF Research Database (Denmark)

In this paper, two stochastic models for the distribution of defects in wind turbine blades are proposed. The first model assumes that the individual defects are completely randomly distributed in the blade. The second model assumes that the defects occur in clusters of different size, based on the assumption that one error in the production process tends to trigger several defects. For both models, additional information, such as number, type, and size of the defects, is included as stochastic variables. In a numerical example, the reliability is estimated for a generic wind turbine blade model both with and without defects in terms of delaminations. The reliability of the blade decreases when defects are included. However, the distribution of the defects influences how much the reliability is decreased. It is also shown how non-destructive inspection (NDI) after production can be used to update the reliability for the wind turbine blade using Bayesian statistics.

Stensgaard Toft, Henrik; Branner, Kim

2011-01-01

299

Defect Distribution and Reliability Assessment of Wind Turbine Blades  

DEFF Research Database (Denmark)

In this paper, two stochastic models for the distribution of defects in wind turbine blades are proposed. The first model assumes that the individual defects are completely randomly distributed in the blade. The second model assumes that the defects occur in clusters of different size, based on the assumption that one error in the production process tends to trigger several defects. For both models, additional information, such as number, type, and size of the defects, is included as stochastic variables. In a numerical example, the reliability is estimated for a generic wind turbine blade model both with and without defects in terms of delaminations. The reliability of the blade decreases when defects are included. However, the distribution of the defects influences how much the reliability is decreased. It is also shown how non-destructive inspection (NDI) after production can be used to update the reliability for the wind turbine blade using Bayesian statistics.

Toft, Henrik Stensgaard; Branner, Kim

2011-01-01

300

Mitigation of Fatigue Loads Using Individual Pitch Control of Wind Turbines Based on FAST  

DEFF Research Database (Denmark)

With the increase of wind turbine dimension and capacity, the wind turbine structures are subjected to prominent loads and fatigue which would reduce the lifetime of wind turbines. Individual pitch control (IPC) is used in this paper to attenuate the blade root bending moment and the tilt and yaw moments and fatigue. The loading transfer from rotational coordinate system to the fixed coordinate system of the wind turbine is analyzed. In order to make the simulation results more reliable, the wind turbine code FAST is applied to doubly fed induction generator (DFIG) based power system to demonstrate the correctness of individual pitch control strategy. The performance of the proposed control method is tested and compared with that using collective pitch control (CPC), demonstrating the effectiveness of individual pitch control of wind turbines.

Zhang, Yunqian; Chen, Zhe

2011-01-01

 
 
 
 
301

Atmospheric stability affects wind turbine power collection  

International Nuclear Information System (INIS)

[en] The power generated by a wind turbine largely depends on the wind speed. During time periods with identical hub-height wind speeds but different shapes to the wind profile, a turbine will produce different amounts of power. This variability may be induced by atmospheric stability, which affects profiles of mean wind speed, direction and turbulence across the rotor disk. Our letter examines turbine power generation data, segregated by atmospheric stability, in order to investigate power performance dependences at a West Coast North American wind farm. The dependence of power on stability is clear, regardless of whether time periods are segregated by three-dimensional turbulence, turbulence intensity or wind shear. The power generated at a given wind speed is higher under stable conditions and lower under strongly convective conditions: average power output differences approach 15%. Wind energy resource assessment and day ahead power forecasting could benefit from increased accuracy if atmospheric stability impacts were measured and appropriately incorporated in power forecasts, e.g., through the generation of power curves based on a range of turbulence regimes. (letter)

2012-01-01

302

Optimal Excitation Controller Design for Wind Turbine Generator  

Directory of Open Access Journals (Sweden)

Full Text Available An optimal excitation controller design based on multirate-output controllers (MROCs) having a multirate sampling mechanismwith different sampling period in each measured output of the system is presented. The proposed H? -control techniqueis applied to the discrete linear open-loop system model which represents a wind turbine generator supplying an infinite busthrough a transmission line.

A. K. Boglou; D. V. Bandekas; D. I. Pappas; C. Potolias

2011-01-01

303

Thermoplastic Composite Wind Turbine Blades: An Integrated Design Approach  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis proposes a new structural design concept for future large wind turbine blades based on fully recyclable thermoplastic composites (TPC). With respect to material properties, cost and processing, reactively processed anionic polyamide-6 (APA-6) has been identified as the most promising the...

Joncas, S.

304

The Vestas Midwest Model wind turbine  

Energy Technology Data Exchange (ETDEWEB)

More than a decade of research, development, and operating experience has made Vestas the leader in wind turbine technology. Vestas research and development specialists use data accumulated from more than 4,500 Vestas turbines operating world-wide to perfect their designs and manufacturing systems. Based on this experience and know-how, part of Vestas product development has concentrated on further evolution and optimizing of the V27-225 kW turbine, which is the most sold wind turbine (1,200 sold units) in the world. The developments have resulted in the introduction of the Midwest Model V29-225kW, which was recently released for commercial sale. The V29-225kW is a specialized version of moderate-to-low wind regimes. The V29-225 kW turbine will provide greater cost effectiveness; improved materials allowing an extension of the blades and modifications have been the important factors in this development. As most other Vestas systems, the V29-225 kW is a pitch regulated upwind turbine with active yaw and a high speed rotor with three blades. The turbine employs full span active pitch with OptiTip{reg_sign}, a high-tech feature that ensures optimum power control and quiet operation.

Poulsen, E.V. [Vestas-American Wind Technology, Inc., Palm Springs, CA (United States)

1995-09-01

305

Overcoming icing effects on wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Wind turbine blades in the Whitehorse area are often subjected to rime icing. High energy winds on ridges, hilltops and mountains result in cloud and rime ice formation. Reliable models and detectors for rime and glaze icing are needed in order to measure the duration and severity of icing. Currently, there is a limited supply of good models on the market, and they do not appear to cope well with severe rime icing. A two heated anemometer approach appears to be reasonably reliable. This paper describes a wind speed and icing event monitoring study at Haeckel Hill in which the performance of an iced turbine was compared with the performance of an ice-free turbine. Technological advancement in the area of blade icing include: the development of low temperature synthetic lubricants and fluids; heated wind instruments and ultrasonics; after-market blade heating systems and blade coatings; and, reductions in energy losses. The challenges that still need to be addressed include: ice detection for severe conditions; off-the-shelf blade heating systems; further reductions in energy losses; and, adaptations of turbine control algorithms. The paper includes a list of manufacturers who are working on equipment for use in cold/icing environments. The large turbine manufacturers include Vestas, Bonus, NEG Micon, Enercon, and Lagerwey. The small turbine manufacturers include Atlantic Orient, Vergnet, Northern Power Systems, and Bergey. 10 figs.

Maissan, J. [Yukon Energy Corp., Whitehorse, YT (Canada)

2003-07-01

306

Evaluating the impact of electrical grid connection on the wind turbine performance for Hofa wind farm scheme in Jordan  

International Nuclear Information System (INIS)

[en] The growth of wind energy is attributed to the development of turbine size and the increase in number of units in each wind farm. The current modern design of large wind turbines (WT) is directed towards producing efficient, sensitive and reliable units. To achieve this goal, modern turbines are equipped with several devices which are operated with highly advanced electronic circuits. Sensing instruments, measuring devices and control processes of major systems and subsystems are based on various types of electronic apparatus and boards. These boards are very sensitive to the voltage variations caused by abnormal conditions in both the turbine itself and the electric grid to which the wind farm is connected. This paper evaluates wind farm records and proposes a number of methods to overcome such obstacles associated with the design of large wind turbines. Several cases of grid abnormality such as sudden feeder interruption due to the short circuit, network disconnection, voltage variation and circuit breaker opening affecting wind turbines operation and availability are classified and presented. The weight of such impact is determined for each type of disturbances associated with electronic problems in the wind turbine. Wind turbine performance at Hofa wind farm scheme in Jordan is taken as a case study

2008-01-01

307

Offshore Wind Turbine Installation Equipment  

Energy Technology Data Exchange (ETDEWEB)

The contents of this presentation concern Present offshore wind market, Present installation methods, GustoMSC installation equipment, Scenarios for future offshore wind, and Future challenges for installation.

Van Nood, N. [Product Development, GustoMSC, Schiedam (Netherlands)

2008-10-15

308

Operational-Condition-Independent Criteria Dedicated to Monitoring Wind Turbine Generators: Preprint  

Energy Technology Data Exchange (ETDEWEB)

To date the existing wind turbine condition monitoring technologies and commercially available systems have not been fully accepted for improving wind turbine availability and reducing their operation and maintenance costs. One of the main reasons is that wind turbines are subject to constantly varying loads and operate at variable rotational speeds. As a consequence, the influences of turbine faults and the effects of varying load and speed are coupled together in wind turbine condition monitoring signals. So, there is an urgent need to either introduce some operational condition de-coupling procedures into the current wind turbine condition monitoring techniques or develop a new operational condition independent wind turbine condition monitoring technique to maintain high turbine availability and achieve the expected economic benefits from wind. The purpose of this paper is to develop such a technique. In the paper, three operational condition independent criteria are developed dedicated for monitoring the operation and health condition of wind turbine generators. All proposed criteria have been tested through both simulated and practical experiments. The experiments have shown that these criteria provide a solution for detecting both mechanical and electrical faults occurring in wind turbine generators.

Yang, W.; Sheng, S.; Court, R.

2012-08-01

309

Assessment and prediction of wind turbine noise  

Energy Technology Data Exchange (ETDEWEB)

The significance of basic aerodynamic noise sources for wind turbine noise are assessed, using information on the aero-acoustic mechanisms of other rotors, which have been studied in depth for many years. From the analysis, areas of potential improvement in wind turbine noise prediction are defined. Suggestions are made for approaches to wind turbine noise control which separate the noise problems at cut-in from those at rated power. Some of these offer the possibility of noise reduction without unfavourable effects on performance. Based on this analysis, a new model for prediction of wind turbine noise is presented and comparisons made between prediction and experiment. The model is based on well established aeroacoustic theory and published laboratory data for the two principal sources, inflow turbulence and boundary layer trailing edge interaction. The new method gives good agreement with experiment with the case studied so far. Parametric trends and sensitivities for the model are presented. Comparisons with previous prediction methods are also given. A consequence of the new model is to put more emphasis on boundary layer trailing edge interaction as a noise source. There are prospects for reducing noise from this source detail changes to the wind turbine design. (author)

Lowson, M.V.

1993-10-01

310

Impact of wind turbines on birds  

Energy Technology Data Exchange (ETDEWEB)

The paper is a review of the present knowledge on impacts of wind turbines on birds, requested by the Danish Ministry of the Environment and Energy. The main conclusions of the review are, that in nearly all the studies so far the numbers of birds recorded colliding with wind turbines have been limited. Some studies indicate that stationary (breeding) birds inside the wind turbine area in the short run habituate to wind turbines, especially the noise and visual impacts, and that the risk for collision becomes low. However, some of the few more long term studies indicate that a negative impact may occur in later generations of breeding birds. In some studies a disturbance effect on bird species, which temporarily stay inside a wind turbine area in order to forage or rest, is observed. The degree of impact is species-specific. An effect is typically recorded inside a zone of up to 250-800 m, with geese and waders as the most sensitive groups of birds. (author)

Clausager, I. [National Environmental Research Institute, Ronde (Denmark); Nohr, H. [Ornis Consult Ltd., Copenhagen (Denmark)

1996-12-31

311

Impact of wind turbines on birds  

International Nuclear Information System (INIS)

The paper is a review of the present knowledge on impacts of wind turbines on birds, requested by the Danish Ministry of the Environment and Energy. The main conclusions of the review are, that in nearly all the studies so far the numbers of birds recorded colliding with wind turbines have been limited. Some studies indicate that stationary (breeding) birds inside the wind turbine area in the short run habituate to wind turbines, especially the noise and visual impacts, and that the risk for collision becomes low. However, some of the few more long term studies indicate that a negative impact may occur in later generations of breeding birds. In some studies a disturbance effect on bird species, which temporarily stay inside a wind turbine area in order to forage or rest, is observed. The degree of impact is species-specific. An effect is typically recorded inside a zone of up to 250-800 m, with geese and waders as the most sensitive groups of birds. (author).

1996-01-01

312

Assessment and prediction of wind turbine noise  

International Nuclear Information System (INIS)

[en] The significance of basic aerodynamic noise sources for wind turbine noise are assessed, using information on the aero-acoustic mechanisms of other rotors, which have been studied in depth for many years. From the analysis, areas of potential improvement in wind turbine noise prediction are defined. Suggestions are made for approaches to wind turbine noise control which separate the noise problems at cut-in from those at rated power. Some of these offer the possibility of noise reduction without unfavourable effects on performance. Based on this analysis, a new model for prediction of wind turbine noise is presented and comparisons made between prediction and experiment. The model is based on well established aeroacoustic theory and published laboratory data for the two principal sources, inflow turbulence and boundary layer trailing edge interaction. The new method gives good agreement with experiment with the case studied so far. Parametric trends and sensitivities for the model are presented. Comparisons with previous prediction methods are also given. A consequence of the new model is to put more emphasis on boundary layer trailing edge interaction as a noise source. There are prospects for reducing noise from this source detail changes to the wind turbine design. (author)

1993-01-01

313

Structural Reliability Aspects in Design of Wind Turbines  

DEFF Research Database (Denmark)

Reliability assessment, optimal design and optimal operation and maintenance of wind turbines are an area of significant interest for the fast growing wind turbine industry for sustainable production of energy. Offshore wind turbines in wind farms give special problems due to wake effects inside the farm. Reliability analysis and optimization of wind turbines require that the special conditions for wind turbine operation are taken into account. Control of the blades implies load reductions for large wind speeds and parking for high wind speeds. In this paper basic structural failure modes for wind turbines are described. Further, aspects are presented related to reliability-based optimization of wind turbines, assessment of optimal reliability level and operation and maintenance.

SØrensen, John Dalsgaard

2007-01-01

314

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

Energy Technology Data Exchange (ETDEWEB)

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

315

Wind Turbine Generator System Duration Test Report for the Mariah Power Windspire Wind Turbine  

Energy Technology Data Exchange (ETDEWEB)

This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project 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 Wind Technology Center (NWTC) as a part of the first round of this project. Duration testing is one of up to five tests that may be performed on the turbines. Other tests include power performance, safety and function, noise, and power quality tests. NWTC testing results provide manufacturers with reports that may be used to meet part of small wind turbine certification requirements. This duration test report focuses on the Mariah Power Windspire wind turbine.

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

2010-05-01

316

Wind turbine manufacturer's perspective on wind turbine noise  

Energy Technology Data Exchange (ETDEWEB)

This slide presentation reviewed how wind turbine manufacturers address the issue of noise. The sources of sound, sound measurement and sound control were outlined along with a brief corporate history of Vestas Canada, a wholly owned subsidiary of Vestas-Americas and Vestas Wind Systems of Denmark, the largest manufacturer of wind turbine generators. The company believes that wind will be a key strategic source of energy and is committed to the Canadian market by actively creating positive wind energy policy in Canada. Current Vestas projects in Canada include 131 MW in Alberta, 150 MW in Saskatchewan, 104 MW in Manitoba, 40 MW in Ontario, 108 MW in Quebec and 30 MW in Nova Scotia for a total of 563 MW. It was noted that wind turbine sound levels are a key siting constraint. As turbines get bigger, the sound level increases, which is a frequent objection to wind turbines. The dominant source of noise on a wind turbine is the aerodynamic noise which is radiated from around the blades. The factors influencing sound level include mechanical noise emission which are nearly constant with wind speed; aerodynamic noise level which is dependent on wind speed at the rotor, pitch angle, rotor RPM, blade geometry, air inflow angle and air turbulence; and the reference wind speed. The result is that noise level depends on wind speed, tower height and site conditions. This presentation outlined the standardized method for measuring wind turbine sound levels and included an illustration of measurement arrangement. The 8 site conditions that influence the site noise emission were also outlined along with a list of good siting practices and appropriate technologies. 11 figs.

Duimering, D. [Vestas, Toronto, ON (Canada)

2005-07-01

317

Study on transient stability of wind turbine with induction generator based on variable pitch control strategy  

DEFF Research Database (Denmark)

In order to enhance and improve the transient stability of a grid-connected wind turbine generator system under the power grid fault, based on typical pitch control strategy of wind turbine, considering the wind turbine system oscillation caused by the drive-train shaft flexibility, Based on Matlab/Simulink, electromagnetic transient state models of the wind tubine generator system and the pitch control models were presented, and the transient behaviors of the wind turbine genarator system using the typical and the proposed pitch control strategies were analyzed and compared when the power grid was subjected to a three-phase short-circuit fault. Also the results were compared with using reactive compensation device. The simulation results show that the proposed pitch control strategy can effectively improve the transient stability of wind turbine generator system.

Zhao, B.; Li, H.

2011-01-01

318

Optimization of wind farm turbines layout using an evolutive algorithm  

International Nuclear Information System (INIS)

The optimum wind farm configuration problem is discussed in this paper and an evolutive algorithm to optimize the wind farm layout is proposed. The algorithm's optimization process is based on a global wind farm cost model using the initial investment and the present value of the yearly net cash flow during the entire wind-farm life span. The proposed algorithm calculates the yearly income due to the sale of the net generated energy taking into account the individual wind turbine loss of production due to wake decay effects and it can deal with areas or terrains with non-uniform load-bearing capacity soil and different roughness length for every wind direction or restrictions such as forbidden areas or limitations in the number of wind turbines or the investment. The results are first favorably compared with those previously published and a second collection of test cases is used to proof the performance and suitability of the proposed evolutive algorithm to find the optimum wind farm configuration. (author)

2010-01-01

319

Design and Development of a Wind Turbine Simulator Using a Separately Excited DC Motor  

Directory of Open Access Journals (Sweden)

Full Text Available Over the course of the past decade, power generation based on wind energy has become a significant component in modern power systems, which has caused substantial increase in the wind power based research. As it is complicated to use a real wind turbine for laboratory purposes, development of a replica of a real wind turbine that can be connected and used indoors is imperative. This paper presents the design and development of a wind turbine simulator that operates on the typical power-speed characteristics of a wind turbine. First, the mathematical model of the wind turbine simulator is developed and the corresponding CAD simulations are carried out. Proposed hardware implementations involve a DC motor-DC generator set, a variable load and a control system based on PI controllers. It is a simple, low power and low cost design that can be easily connected to an AC system through an inverter.

K. K. M. S. Kariyawasam; K. K. N. P. Karunarathna; R. M. A. Karunarathne; M. P. D. S. C. Kularathne; K. T. M. U. Hemapala

2013-01-01

320

An investigation of the levels of electromagnetic radiation generated by wind turbines  

International Nuclear Information System (INIS)

[en] The issue of electromagnetic interference is arising with some regularity as various wind energy projects throughout the UK reach the stage where local authority planning approval is sought. To many of the parties involved, wind turbines represent an unknown quantity and hence objections to their siting must be expected. Wind turbines may cause electromagnetic interference through two quite distinct processes. The first occurs when the wind turbine scatters electromagnetic signals passing through the area of the site and essentially, provides a second path between the transmitter and receiver of the signal. The second source of interference arises when signals generated within the wind turbine itself affect communications equipment or, indeed, any electronic circuitry. A case in point is a wind farm project under development by Bonython Estates of Cornwall. The aim of this project was to investigate the emissions from the wind turbines proposed for the Bonython development. This was achieved by means of field measurements on existing installations. (author)

1992-01-01

 
 
 
 
321

Modeling of wind turbines for power system studies  

Energy Technology Data Exchange (ETDEWEB)

When wind turbines are installed into the electric grid, the power quality is affected. Today, strict installation recommendations often prevail due to a lack of knowledge on this subject. Consequently, it is important to predict the impact of wind turbines on the electric grid before the turbines are installed. The thesis describes relevant power quality issues, discusses different configurations of wind turbines with respect to power quality and draw requirements regarding wind turbine modeling. A model of a stall-regulated, fixed-speed wind turbine system is introduced and its power quality impact on the electric grid is evaluated. The model is verified with field measurements.

Petru, T.

2001-05-01

322

Replacement of older wind turbines - perspectives and measures in Denmark  

International Nuclear Information System (INIS)

A replacement program has been initiated in Denmark. The aims and spin-offs of this program are: removal of old and small wind turbines scattered sited in the open land, mitigation of neighbor complains, mitigation of the small but increasing public disapproval of wind turbines, an enlarged total MW-potential, a stimulation of the wind turbine market, and an economical relieve of pioneer wind turbine owners. The replacement program is based on subsidies to owners who are replacing their old or misplaced turbines. Five month into the program 16 turbines have been replaced, and 3.5 MW of wind power capacity has been added. (au).

1995-01-01

323

OUT Success Stories: Advanced Airfoils for Wind Turbines  

International Nuclear Information System (INIS)

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

2000-01-01

324

Effects of Wind Turbine Farms on Air Defence Radars.  

Science.gov (United States)

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

325

Magnus wind turbines as an alternative to the blade ones  

International Nuclear Information System (INIS)

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.

2007-01-01

326

Analysis and estimation of transient stability for a grid-connected wind turbine with induction generator  

DEFF Research Database (Denmark)

Increasing levels of wind energy in modern electrical power system is initiating a need for accurate analysis and estimation of transient stability of wind turbine generation systems. This paper investigates the transient behaviors and possible direct methods for transient stability evaluation of a grid-connected wind turbine with squirrel cage induction generator (SCIG). Firstly, by using an equivalent lump mass method, a three-mass wind turbine equivalent model is proposed considering both the blades and the shaft flexibility of the wind turbine drive train system. Combined with the detailed electromagnetic transient models of a SCIG, the transient behaviors of the wind turbine generation system during a three-phase fault are simulated and compared with the traditional models. Secondly, in order to quickly estimate the transient stability limit of the wind turbine generation system, a direct method based on normal form theory is proposed. The transient models of the wind turbine generation system including the flexible drive train model are derived based on the direct transient stability estimation method. A method of critical clearing time (CCT) calculation is developed for the transient stability estimation of the wind turbine generation system. Finally, the CCT at various initial mechanical torques for different dynamical models are calculated and compared with the trial and error method by simulation, when the SCIG stator terminal is subjected to a three-phase short-circuit fault. The results have shown the proposed method and models are correct and valid.

Li, H.; Zhao, B.

2011-01-01

327

Performance of spanish wind turbines  

International Nuclear Information System (INIS)

In this document we can find a statistical evaluation for the wind energy generation from each spanish wind farm referred to 1994, going on with the work that has been carried out since 1992, by initiative of the Wind Energy Division from Renewable Energy Institute. The purpose of this work is to contribute with interesting information for the wind environment and offer a global view from monthly performances of different wind farms. (Author)

1995-01-01

328

Rotationally sampled wind and MOD-2 wind turbine response. Final report  

Energy Technology Data Exchange (ETDEWEB)

In an effort to learn more about how wind behaves hear wind turbines, researchers rotationally sampled winds by attaching sensors to the blades of a MOD-2 wind turbine. This fieldwork demonstrates the feasibility of a blade-mounted measuring technique and provides new data on the winds encountered by a rotating turbine blade.

Connell, J.R.; George, R.L.; Morris, V.R.; Sandborn, V.A.

1985-11-01

329

Feasibility of monitoring large wind turbines using photogrammetry  

Energy Technology Data Exchange (ETDEWEB)

Photogrammetry, which is a proven measurement technique based on determination of the 3D coordinates of the points on an object by using two or more images taken from different positions, is proposed to be a promising and cost efficient alternative for monitoring the dynamic behavior of wind turbines. The pros and cons of utilizing this measurement technique for several applications such as dynamic testing or health monitoring of large wind turbines are discussed by presenting the results of the infield tests performed on a 2.5 MW - 80 m diameter - wind turbine. Within the scope of the work, the 3D dynamic response of the rotor is captured at 33 different locations simultaneously by using 4 CCD (charge coupled device) cameras while the turbine is rotating. Initial results show that the deformations on the turbine can be measured with an average accuracy of {+-}25 mm from a measurement distance of 220 m. Preliminary analyses of the measurements also show that some of the important turbine modes can be identified from photogrammetric measurement data. (author)

Ozbek, Muammer; Rixen, Daniel J. [Delft University of Technology, Faculty of Mechanical Engineering, Mekelweg 2, 2628CD Delft (Netherlands); Erne, Oliver; Sanow, Gunter [GOM mbH (Optical Measuring Techniques), Mittelweg 7-8, 38106 Braunschweig (Germany)

2010-12-15

330

Electrical generating systems in wind turbine applications  

Energy Technology Data Exchange (ETDEWEB)

The aim of this paper is to give a survey of the electrical systems used in wind turbine applications. Synchronous as well as induction generators are investigated. Line-commutated thyristor converters are compared with force-commutated transistor converters. System characteristics are investigated regarding power quality, capability of damping resonance, losses and costs. Several recommendations regarding the turbine and the connection to the grid are discussed. 16 refs, 2 figs, 1 tab

Larsson, Aake; Carlson, Ola [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electrical Machines and Power Electronics; Siden, G. [Halmstad Univ. (Sweden). Dept. of Technology and Natural Science

1995-12-31

331

Wind turbine arrangement. [Magnus effect]. Vindturbinanordning  

Energy Technology Data Exchange (ETDEWEB)

In this turbine arrangement is the so called Magnus-effect utilized. To a point hub are a number of rotable light bodies fitted. When each of this bodies is brought to rotate by means of an electric motor a pressure difference is created when simultaneously a wind blows against the bodies. The pressure difference give the turbine shaft a turning movement which may be utilized in a known manner. (L.F.).

Svegner, B.

1990-11-05

332

Methods of making wind turbine rotor blades  

Science.gov (United States)

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

333

Electromagnetic Interference on Large Wind Turbines  

Directory of Open Access Journals (Sweden)

Full Text Available Electromagnetic interference (EMI) can both affect and be transmitted by mega-watt wind turbines. This paper provides a general overview on EMI with respect to mega-watt wind turbines. Possibilities of measuring all types of electromagnetic interference are shown. Electromagnetic fields resulting from a GSM transmitter mounted on a mega-watt wind turbine will be analyzed in detail. This cellular system operates as a real-time communication link. The method-of-moments is used to analytically describe the electro-magnetic fields. The electromagnetic interference will be analyzed under the given boundary condition with a commercial simulation tool. Different transmitter positions are judged on the basis of their radiation patterns. The principal EMI mechanisms are described and taken into consideration.

Florian Krug; Bastian Lewke

2009-01-01

334

Resonant vibration control of wind turbine blades  

DEFF Research Database (Denmark)

The paper deals with introduction of damping to specific vibration modes of wind turbine blades, using a resonant controller with acceleration feedback. The wind turbine blade is represented by three-dimensional, two-node finite elements in a local, rotating frame of reference. The element formulation accounts for arbitrary mass density distributions, general elastic crosssection properties and geometric stiffness effects due to internal stresses. A compact, linear formulation for aerodynamic forces with associated stiffness and damping terms is established and added to the structural model. The efficiency of the resonant controller is demonstrated for a representative turbine blade exposed to turbulent wind loading. It is found that the present explicit tuning procedure yields close to optimal tuning, with very limited modal spill-over and effective reduction of the vibration amplitudes.

Svendsen, Martin Nymann Technical University of Denmark,

2010-01-01

335

Shoosing the appropriate size wind turbine  

Energy Technology Data Exchange (ETDEWEB)

Within the past several years, wind turbines rated at 400 kW and higher have been introduced into the market, and some manufacturers are developing machines rated at 750 - 1,000+ kW. This raises the question: What is the appropriate size for utility-grade wind turbines today? The answer depends upon the site where the machines will be used and the local conditions. The issues discussed in the paper are: (1) Site-Related (a) Visual, noise, erosion, television interference, interference with aviation (b) Siting efficiency (2) Logistics (a) Adequacy of roads and bridges to accept large vehicles (b) Availability and cost of cranes for erection and maintenance (c) Capability of local repair/overhauls (3) Cost Effectiveness (a) Capital costs (1) Wind Turbine (2) Infrastructure costs (b) Maintenance costs (4) Technical/Financial Risk. 1 fig., 1 tab.

Lynette, R. [FloWind Corp., San Rafael, CA (United States)

1996-12-31

336

Two LQRI based Blade Pitch Controls for Wind Turbines  

Directory of Open Access Journals (Sweden)

Full Text Available As the wind turbine size has been increasing and their mechanical components are built lighter, the reduction of the structural loads becomes a very important task of wind turbine control in addition to maximum wind power capture. In this paper, we present a separate set of collective and individual pitch control algorithms. Both pitch control algorithms use the LQR control technique with integral action (LQRI), and utilize Kalman filters to estimate system states and wind speed. Compared to previous works in this area, our pitch control algorithms can control rotor speed and blade bending moments at the same time to improve the trade-off between rotor speed regulation and load reduction, while both collective and individual pitch controls can be designed separately. Simulation results show that the proposed collective and individual pitch controllers achieve very good rotor speed regulation and significant reduction of blade bending moments.

Sungsu Park; Yoonsu Nam

2012-01-01

337

Wind shear climatology for large wind turbine generators  

Energy Technology Data Exchange (ETDEWEB)

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

338

Wind energy and the trend towards megawatt turbines  

International Nuclear Information System (INIS)

The economic potential for wind energy in Europe and the trend towards megawatt turbines is discussed. It is expected that the portion of wind energy in the total power production in Europe will rise to 2 percent in 2000. Presently, the power generation by wind energy is economically feasible for wind turbines with a capacity of 300 to 400 k W. The present technologic evolution indicates that larger and lighter wind turbines will be developed. A clear trend towards megawatt turbines in wind parks or clusters is observed. Commercially developed megawatt turbines are expected to become available during the coming 3 to 5 years. (A.S.)

1994-01-01

339

Amplitude modulation of wind turbine noise  

CERN Document Server

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

Makarewicz, Rufin

2013-01-01

340

Innovative system for wind turbine testing  

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-07-01

 
 
 
 
341

Modeling of Wind Turbine Gearbox Mounting  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper three bushing models are evaluated to find a best practice in modeling the mounting of wind turbine gearboxes. Parameter identification on measurements has been used to determine the bushing parameters for dynamic simulation of a gearbox including main shaft. The stiffness of the main components of the gearbox has been calculated. The torsional stiffness of the main shaft, gearbox and the mounting of the gearbox are of same order of magnitude, and eigenfrequency analysis clearly reveals that the stiffness of the gearbox mounting is of importance when modeling full wind turbine drivetrains.

Morten Haastrup; Michael R. Hansen; Morten K. Ebbesen

2011-01-01

342

Aspects of unsteady aerodynamics in wind turbines  

Energy Technology Data Exchange (ETDEWEB)

This presentation is primarily about unsteady aerodynamics in relation to wind turbines. It is divided into three very distinct sections: (1) Basic unsteady aerodynamics; (2) VAWT performance modelling and (3) Passive stall regulation of VAWTs. The aim of the presentation is to illustrate that, if desired, future wind turbine blades could be aerodynamically tailored to exploit the unsteady nature of the VAWT flow with far greater confidence and insight than has been hitherto possible. To this effect, the collaborating British research teams and, in particular, VAWT Ltd. have assembled sufficient knowledge for such a conclusion to be made. (author).

Galbraith, R.A.McD.; Niven, A.J.; Coton, F.N. (Glasgow Univ. (GB). Dept. of Aerospace Engineering)

1990-01-01

343

Spectral coherence in wind turbine wakes  

Energy Technology Data Exchange (ETDEWEB)

Spectral coherence in the wake of a wind turbine situated in a wind farm has been investigated. Results are presented for lateral coherence at two heights with 5 m separation and vertical coherence at 13 m separation at different downstream stations in the wake. Also presented is the decay of turbulence generated by the wake. The results show that turbulence from the wake is still noticeable 15 diameters from the turbine, lateral coherence in the near-wake is decreased relative to conventional models, but from 8 rotor diameters on, the lateral coherence seems unaffected by the wake. The vertical coherence shows only little influence by the wake

Hoejstrup, Joergen [Wind Energy and Atmospheric Physics Department, Risoe National Laboratory, DK-4000 Roskilde (Denmark)

1999-03-01

344

Dynamic stall on wind turbine blades  

Energy Technology Data Exchange (ETDEWEB)

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

345

Impact of wind turbines on birdlife  

International Nuclear Information System (INIS)

[en] An overview of wind energy programmes is presented, as well as an analysis of recent studies on the title subject and data on the attitude of nature conservation organisations both from the USA and Europe. The studies were analyzed for legitimacy of assumptions and validity of the conclusions. Most of the wind energy programs and all European studies deal with bird kills and disturbance in coastal areas. The number of victims per turbine per year in this type of area appears to be acceptable. The disturbing effect of wind turbines on breeding birds appears to be negligible. The disturbance of resting and migrating birds by wind turbines however is reasonably clear. As a result of international concern several sites have been designated where siting of wind turbines is prohibited. Well known examples are wetlands of international importance (Ramsar-convention) and European Community Special Protection Areas. Major concern among conservationists is the location of many valuable and vulnerable environmental resources outside the protected areas. Negative attitudes towards wind energy projects are not particularly due to avian considerations, but rather to a general objective to protect landscapes and habitats, undisturbed by human infrastructures and disturbance. It is concluded that all new locations for wind energy projects should be weighed on the disturbance aspect. Reference data for such a weigh are available for coastal areas, although the impact on local migration between feeding grounds and high water refugee areas needs further research. Future research is also needed for application of wind energy both on off-shore locations, grasslands and farmlands. Wind energy developers and conservationists should have a close contact in order to establish consensus on how to deal with remaining uncertainties. 7 figs., 9 tabs., 5 appendices, 37 refs

1993-01-01

346

Power generation from wind turbines in a solar chimney  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recent studies have shown that shrouded wind turbines can generate greater power compared to bare turbines. A solar chimney generates an upward draft of wind inside a tower and a shroud around the wind turbine. There are numerous empty silos on farms in the U.S. that can be converted to solar chim...

Tudor Foote, Ramesh K. Agarwal

347

Experiments with a diffuser augmented model wind turbine  

Energy Technology Data Exchange (ETDEWEB)

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

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

1982-03-01

348

Duration Test Report for the Entegrity EW50 Wind Turbine  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-12-01

349

Structured Linear Parameter Varying Control of Wind Turbines  

DEFF Research Database (Denmark)

High performance and reliability are required for wind turbines to be competitive within the energy market. To capture their nonlinear behavior, wind turbines are often modeled using parameter-varying models. In this chapter, a framework for modelling and controller design of wind turbines is presented. We specifically consider variable-speed, variable-pitch wind turbines with faults on actuators and sensors. Linear parameter-varying (LPV) controllers can be designed by a proposed method that allows the inclusion of faults in the LPV controller design. Moreover, the controller structure can be arbitrarily chosen: static output feedback, dynamic (reduced order) output feedback, decentralized, among others. The controllers are scheduled on an estimated wind speed to manage the parametervarying nature of the model and on information from a fault diagnosis system. The optimization problems involved in the controller synthesis are solved by an iterative LMI-based algorithm. The resulting controllers can also be easily implemented in practice due to low data storage and simple math operations. The performance of the LPV controllers is assessed by nonlinear simulations results.

Adegas, Fabiano Daher; Sloth, Christoffer

2012-01-01

350

The North Wind 100 wind turbine, a turbine designed specifically for cold climates  

Energy Technology Data Exchange (ETDEWEB)

The development of a wind turbine designed to serve energy needs at circumpolar locations around the world was described. The North Wind 100 turbine was developed by Northern Power Systems with support from NSF, NASA, and NREL. Wind energy is considered to be the most viable year round renewable energy supply option for circumpolar locations. In January 1997, a modified HR3 wind turbine was installed at the South Pole to test the turbine`s ability to work in extremely cold temperatures (-85 degrees C). The turbine featured low air density, low average wind speed of 11.5 mph annual average, its limited service and maintenance capability and limited logistic and construction support requirement. The year long operating experience was better than originally predicted. The North Wind 100, Cold Weather Version will be the first commercial version of the turbine to be developed. It is suited for small village applications in circumpolar regions such as Northern Alaska, Canada, Europe and Asia. 2 figs.

Coleman, C. [Northern Power Systems, Waitsfield, VT (United States)

1998-05-01

351

Wind power integration: from individual wind turbine to wind park as a power plant  

Digital Repository Infrastructure Vision for European Research (DRIVER)

As power capacities of single wind turbine, single wind park and total wind power installation are continuously increasing, the wind power begins to challenge the safety operation of the power system. This thesis focuses on the grid integration aspects such as the dynamic behaviours of wind power du...

Zhou, Y.

352

Damping Wind and Wave Loads on a Floating Wind Turbine  

Directory of Open Access Journals (Sweden)

Full Text Available Offshore wind energy capitalizes on the higher and less turbulent wind speeds at sea. To enable deployment of wind turbines in deep-water locations, structures are being explored, where wind turbines are placed on a floating platform. This combined structure presents a new control problem, due to the partly unconstrained movement of the platform and ocean wave excitation. If this additional complexity is not dealt with properly, this may lead to a significant increase in the structural loads and, potentially, instability of the controlled system. In this paper, the wave excitation is investigated, and we show the influence that both wind speed, wave frequencies and misalignment between wind and waves have on the system dynamics. A new control model is derived that extends standard turbine models to include the hydrodynamics, additional platform degrees of freedom, the platform mooring system and tower side-side motion, including gyroscopic effects. The models support a model-based design that includes estimators for wind speed and wave frequency. The design is applied to a number of examples representing different wind and wave conditions and successfully demonstrates a reduction in the structural oscillations, while improving power performance.

Søren Christiansen; Thomas Bak; Torben Knudsen

2013-01-01

353

Damping Wind and Wave Loads on a Floating Wind Turbine  

DEFF Research Database (Denmark)

Offshore wind energy capitalizes on the higher and less turbulent wind speeds at sea. To enable deployment of wind turbines in deep-water locations, structures are being explored, where wind turbines are placed on a floating platform. This combined structure presents a new control problem, due to the partly unconstrained movement of the platform and ocean wave excitation. If this additional complexity is not dealt with properly, this may lead to a significant increase in the structural loads and, potentially, instability of the controlled system. In this paper, the wave excitation is investigated, and we show the influence that both wind speed, wave frequencies and misalignment between wind and waves have on the system dynamics. A new control model is derived that extends standard turbine models to include the hydrodynamics, additional platform degrees of freedom, the platform mooring system and tower side-side motion, including gyroscopic effects. The models support a model-based design that includes estimators for wind speed and wave frequency. The design is applied to a number of examples representing different wind and wave conditions and successfully demonstrates a reduction in the structural oscillations, while improving power performance.

Christiansen, SØren; Bak, Thomas

2013-01-01

354

European wind turbine testing procedure developments. Task 1: Measurement method to verify wind turbine performance characteristics  

Energy Technology Data Exchange (ETDEWEB)

There is currently significant standardisation work ongoing in the context of wind farm energy yield warranty assessment and wind turbine power performance testing. A standards maintenance team is revising the current IEC (EN) 61400-12 Ed 1 standard for wind turbine power performance testing. The standard is being divided into four documents. Two of them are drafted for evaluation and verification of complete wind farms and of individual wind turbines within wind farms. This document, and the project it describes, has been designed to help provide a solid technical foundation for this revised standard. The work was wide ranging and addressed 'grey' areas of knowledge, regarding existing methodologies or to carry out basic research in support of fundamentally new procedures. The work has given rise to recommendations in all areas of the work, including site calibration procedures, nacelle anemometry, multi-variate regression analysis and density normalisation. (au)

Hunter, R.; Friis Pedersen, T.; Dunbabin, P.; Antoniou, I.; Frandsen, S.; Klug, H.; Albers, A.; Lee, W.K.

2001-01-01

355

Using Neural Networks to Estimate Wind Turbine  

UK PubMed Central (United Kingdom)

This paper uses data collected at Central and SouthWest Services Fort Davis wind farm to develop a neural networkbased prediction of power produced by each turbine. The powergenerated by electric wind turbines changes rapidly because ofthe continuous fluctuation of wind speed and direction. It is importantfor the power industry to have the capability to performthis prediction for diagnostic purposes---lower-than-expected windpower may be an early indicator of a need for maintenance. Inthis paper, characteristics of wind power generation are first evaluatedin order to establish the relative importance for the neuralnetwork. A four input neural network is developed and its performanceis shown to be superior to the single parameter traditionalmodel approach.

Edgar A. O'hair; Shuhui Li; Donald C. Wunsch; Michael G. Giesselmann; Senior Member

356

Power Electronics Converters for Wind Turbine Systems  

DEFF Research Database (Denmark)

The steady growth of installed wind power together with the upscaling of the single wind turbine power capability has pushed the research and development of power converters toward full-scale power conversion, lowered cost pr kW, increased power density, and also the need for higher reliability. In this paper, power converter technologies are reviewed with focus on existing ones and on those that have potential for higher power but which have not been yet adopted due to the important risk associated with the high-power industry. The power converters are classified into single- and multicell topologies, in the latter case with attention to series connection and parallel connection either electrical or magnetic ones (multiphase/windings machines/transformers). It is concluded that as the power level increases in wind turbines, medium-voltage power converters will be a dominant power converter configuration, but continuously cost and reliability are important issues to be addressed.

Blaabjerg, Frede; Liserre, Marco

2012-01-01

357

The power fluctuations of a wind turbine  

Energy Technology Data Exchange (ETDEWEB)

At the beginning of the paper the power fluctuations in the case of a sinusoidal gust are investigated. A quasi-steady model is derived. Then this model is corrected to account for the dynamic characteristics of the turbine. The correction is introduced using a special correction function which is obtained after running a complete dynamic model of the wind turbine. It is shown that for each value of average wind speed there is, for practical purposes, a linear relation between the intensity of power fluctuations and the product of the intensity of turbulence and the above-mentioned correction function. The derivation for a sinusoidal gust is the basis for the analysis of the power fluctuations in the case of a `real` wind. The model for `real` wind is validated by comparing its results with field measurements

Rosen, A; Sheinman, Y [Faculty of Aerospace Engineering, Technion - Israel Institute of Technology, Haifa (Israel)

1996-01-01

358

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

Energy Technology Data Exchange (ETDEWEB)

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

359

Lift Augmentation for Vertical Axis Wind Turbines  

Directory of Open Access Journals (Sweden)

Full Text Available The concept of harnessing wind power has been around for centuries, and is first recorded by the Persians in 900 AD. These early uses of wind power were for the processing of food, particularly grinding grains, and consisted of stationary blades around a horizontal axis, the precursor to today’s horizontal axis wind turbines (HAWT). Technology for these wind mills was essentially the same until the 1930’s when advances in aircraft propeller theories were applied to the blades of the turbine. During this development period, which has since remained basically unchanged, the design push was for increasingly larger propellers requiring heavy and costly transmissions, generators, and support towers to be installed. An alternative concept to the HAWT was developed by Georges Darrieus [5], which utilized a vertical shaft and is known as a vertical axis wind turbine (VAWT). The scientific development of the concept did not gain strong attention until the 1970’s due to the perceived low efficiency of this style. This perception was due in part to the portion of the blade’s rotary path that is adverse to the generation of power. This efficiency loss can be minimized by the mechanical movement of the blade, relative to the airflow during the upwind portion of the blades’ rotational path. Since, circulation control can alter the forces generated by an airfoil, it could be used to increase the efficiency of a VAWT by increasing the torque produced on the downwind portion of the path, while removing the need for a physical change in angle of attack. With the recent upturn in petroleum costs and global warming concerns, interest in renewable energy technologies have been reinvigorated, in particular the desire for advanced wind energy technologies, including the application of lift augmentation techniques. One of these techniques is to utilize circulation control to enhance the lifting capacity of the blades based on the location of the blade in the turbine’s rotation. Though this technology can be applied to any wind turbine, whether horizontal or vertical axis, this paper focuses on the application of circulation control for VAWT’s due primarily to reduced hardware complexities and to increase the performance of this design thus helping to level the playing field between the two styles. This performance enhancement coupled with the ability to locate the primary components near the ground allows for easier installation, troubleshooting, maintenance, and future improvement of the circulation control sub-system. By varying the circulation control performance with the blade position, the coefficient of performance, Cp, of the wind turbine can be altered. This variation in Cp resembles a change in the effective solidity factor, the non-dimensional characteristic that accounts for the number of turbine blades, chord length, and turbine radius. The solidity factor is typically used in the design of a wind turbine with its peak performance occurring at various tip speed ratios, at different solidity factors. Prior to the construction of physical models, analytical methods, namely a vortex model, was used to estimate the performance enhancement potential of the blade force augmentation via circulation control. These results were then used to construct and test a wind tunnel blade section model to obtain lift and drag values for a full range of rotational angles. These results were then supplied to the vortex model which indicated that through the addition of circulation control to the blades of a vertical axis wind turbine an approximately 20% improvement in the annual energy production, and consequently the capacity factor, could be achieved.

Gerald M Angle II; Mary Ann Clarke

2010-01-01

360

Grid fault and design-basis for wind turbines. Final report  

Energy Technology Data Exchange (ETDEWEB)

This is the final report of a Danish research project 'Grid fault and design-basis for wind turbines'. The objective of this project has been to assess and analyze the consequences of the new grid connection requirements for the fatigue and ultimate structural loads of wind turbines. The fulfillment of the grid connection requirements poses challenges for the design of both the electrical system and the mechanical structure of wind turbines. The development of wind turbine models and novel control strategies to fulfill the TSO's requirements are of vital importance in this design. Dynamic models and different fault ride-through control strategies have been developed and assessed in this project for three different wind turbine concepts (active stall wind turbine, variable speed doublyfed induction generator wind turbine, variable speed multipole permanent magnet wind turbine). A computer approach for the quantification of the wind turbines structural loads caused by the fault ride-through grid requirement, has been proposed and exemplified for the case of an active stall wind turbine. This approach relies on the combination of knowledge from complimentary simulation tools, which have expertise in different specialized design areas for wind turbines. In order to quantify the impact of the grid faults and grid requirements fulfillment on wind turbines structural loads and thus on their lifetime, a rainflow and a statistical analysis for fatigue and ultimate structural loads, respectively, have been performed and compared for two cases, i.e. one when the turbine is immediately disconnected from the grid when a grid fault occurs and one when the turbine is equipped with a fault ride-through controller and therefore it is able to remain connected to the grid during the grid fault. Different storm control strategies, that enable variable speed wind turbines to produce power at wind speeds higher than 25m/s and up to 50m/s without substantially increasing the structural loads, have also been proposed and investigated during the project. Statistics in terms of mean value and standard deviation have been analysed and rainflow calculations have been performed to estimate the impact over the lifetime of a variable speed wind turbine. (author)

Hansen, A.D.; Cutululis, N.A.; Markou, H.; Soerensen, Poul; Iov, F.

2010-01-15

 
 
 
 
361

Small Wind Turbine Applications: Current Practice in Colorado  

International Nuclear Information System (INIS)

[en] Numerous small wind turbines are being used by homeowners in Colorado. Some of these installations are quite recent while others date back to the federal tax-credit era of the early 1980s. Through visits with small wind turbine owners in Colorado, I have developed case studies of six small wind energy applications focusing on the wind turbine technology, wind turbine siting, the power systems and electric loads, regulatory issues, and motivations about wind energy. These case studies offer a glimpse into the current state-of-the-art of small-scale wind energy and provide some insight into issues affecting development of a wider market

1999-01-01

362

Options for wind turbines in the Netherlands  

International Nuclear Information System (INIS)

[en] By order of the Netherlands Agency for Energy and the Environment (Novem) Ecofys carried out a study on the options for wind energy in interior locations in the Netherlands. Attention is paid to points of view, current initiatives, financial and technical marginal conditions and bottlenecks. The results of the study can be used to set up demonstration projects for wind turbines in the interior part of the Netherlands. 10 refs

1998-01-01

363

Control Logic Algorithm for Medium Scale Wind Turbines  

Directory of Open Access Journals (Sweden)

Full Text Available Recently, sustainable attention has been drawn to renewable energy sources. Wind energy systems as renewable source of energy have been extensively studied because of its benefits as an environmentally friendly clean energy, inexhaustible, safe and a low-cost for long term. Because of its unpredictable availability, power management control algorithms are essential to extract as much power as possible from the wind during its availability durations. This paper is motivated for proposing the main control algorithm for wind turbines each incorporating two generators. The proposed main algorithm contains several sub algorithm models (strategies) for power control, pitch control, status checking, starting, grid connection, normal and emergency shutdown that are studied, designed and also, tested under operation. The testing phase shows that in the high wind speed range, the pitch control seems the most relevant to release a power margin. While in the low wind speed range, the increase of the rotation speed is more convenient.

Osama Abdel Hakeem Abdel Sattar; R. R. Darwish; Saad Mohamed Ali Eid; Elsayed Mostafa Saad

2012-01-01

364

PowerJet Wind Turbine Project  

Energy Technology Data Exchange (ETDEWEB)

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 electrical wires were fully contained inside

Bartlett, Raymond J

2008-11-30

365

Built-Environment Wind Turbine Roadmap  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-11-01

366

Noise measurements in 4 wind turbine farms  

International Nuclear Information System (INIS)

[en] The title wind turbine arrays are situated in Herbayum (Newinco 23PI250), Callantsoog (Bouma 160/20), Noordoostpolder (Windmaster WM300), and Ulketocht (Newinco 500 kW). Measurements were carried out by means of the so-called Ecofys Correlating Noise Meter to determine the source level of the wind turbines. The resulting source level as a function of the wind speed is interpolated to a source level for a wind speed of 8 m/s at 10 m height, on the basis of which the noise contours can be calculated. The noise contours are determined to analyze the noise load for people living in the neighbourhood of the wind parks. The source levels are compared with values as indicated in certificates, which are granted on the basis of a so-called Restricted Quality Certificate (BKC, abbreviated in Dutch) or the new standard NNI 6096/2 for the above-mentioned wind turbines. In general the results of this study agree quite well with the certified values. 12 figs., 7 tabs., 6 refs

1993-01-01

367

Wind Turbines on CO2 Neutral Luminaries in Urban Areas  

DEFF Research Database (Denmark)

In the present work, an overview of three different wind turbines used in hybrid luminaries is presented. The turbines are: vertical-axis twisted Savonius, three-blade horizontal-axis, and vertical-axis three-blade helical H-rotor. The considered luminaries are also equipped with photovoltaic panels and batteries, detailed investigation of which is outside the scope of the present manuscript. Analysis of the turbines’ performance based on producer-supplied power curves is presented together with an estimation of the wind climate in Copenhagen district comprising 1-2 story single family buildings. A new vertical-axis twisted Savonius rotor is proposed for a luminary being designed for such a district within the “Development of CO2 neutral urban luminary” project.

Skrzypinski, Witold Robert; Bak, Christian

2013-01-01

368

Upstream and lateral wind turbine wake effects on nearby wind turbine performance  

Energy Technology Data Exchange (ETDEWEB)

A selection of different 1:50 scale rotor blades were evaluated with dynamometers, force balances, and wake measurements to select a rotor model which correctly simulates the full-scale behavior of an actual wind mill. A wind-tunnel measurement program was then carried out on a set of five dynamic (operating) wind mills placed at various heights and orientations to one another. The interdependence of wind-turbine performance on such spacing was determined. 10 figs., 14 refs., 1 tab.

Neff, D.E.; Meroney, R.N. (Colorado State Univ., Fort Collins (USA)); McCarthy, E.; Davis, E. (U.S. Windpower, Inc., Livermore, CA (USA))

1990-10-01

369

Leasing wind turbines (and its alternatives)  

Energy Technology Data Exchange (ETDEWEB)

The financing of wind farms has historically consisted of a mixture of traditional debt and equity, with debt generally being provided by high street or specialist banks, through inter-company loans, or from International Funding Agencies (IFA's) via National Funding Agencies in developing countries. The use of more innovative financing methods has to date been limited. One possible methods of attracting finance for wind farms is the leasing of wind turbines, and this paper sets out the reasons leasing is particularly appropriate for renewable energy (RE) projects (in particular wind farms), the effect leasing may have on returns available to investors, and some of the obstacles that have to be overcome by the RE and wind industry to increase the utilisation of leasing. This paper concludes by discussing the possibility of using a pan-European leasing company as means of providing overseas aid to developing countries, thereby facilitating the implementation of wind energy in these important regions. (Author)

Johns, Jonathan H. [Ernst and Young UK, Renewable Energy Unit, Exeter (United Kingdom)

1999-04-01

370

Leasing wind turbines (and its alternatives)  

Energy Technology Data Exchange (ETDEWEB)

The financing of wind farms has historically consisted of a mixture of traditional debt and equity, with debt generally being provided by high street or specialist banks, through inter-company loans, or from International Funding Agencies (IFA`s) via National Funding Agencies in developing countries. The use of more innovative financing methods has to date been limited. One possible methods of attracting finance for wind farms is the leasing of wind turbines, and this paper sets out the reasons leasing is particularly appropriate for renewable energy (RE) projects (in particular wind farms), the effect leasing may have on returns available to investors, and some of the obstacles that have to be overcome by the RE and wind industry to increase the utilisation of leasing. This paper concludes by discussing the possibility of using a pan-European leasing company as means of providing overseas aid to developing countries, thereby facilitating the implementation of wind energy in these important regions. (Author)

Johns, Jonathan H. [Ernst and Young UK, Renewable Energy Unit, Exeter (United Kingdom)

1999-01-01

371

Leasing wind turbines (and its alternatives)  

International Nuclear Information System (INIS)

The financing of wind farms has historically consisted of a mixture of traditional debt and equity, with debt generally being provided by high street or specialist banks, through inter-company loans, or from International Funding Agencies (IFA's) via National Funding Agencies in developing countries. The use of more innovative financing methods has to date been limited. One possible methods of attracting finance for wind farms is the leasing of wind turbines, and this paper sets out the reasons leasing is particularly appropriate for renewable energy (RE) projects (in particular wind farms), the effect leasing may have on returns available to investors, and some of the obstacles that have to be overcome by the RE and wind industry to increase the utilisation of leasing. This paper concludes by discussing the possibility of using a pan-European leasing company as means of providing overseas aid to developing countries, thereby facilitating the implementation of wind energy in these important regions. (Author)

1999-01-01

372

Method for fabricating wind turbine blades  

Energy Technology Data Exchange (ETDEWEB)

The manufacture of large scale wind turbine blades is accomplished by winding composite fiber materials onto a mandrel to form the desired airfoil shape. The winding process requires that the fibers always maintain contact with the mandrel surface. If the surface is concave the fibers will form a bridge over the concave surface portion which produces a void. This invention avoids bridging by analysis of the mandrel surface design including the steps of defining a plurality of coordinate points on the surface prior to winding thereof, and determining if a concavity will occur in the fiber winding plane passing through each coordinate point. If a concavity is located, the mandrel design coordinate point at the concavity is modified to eliminate the concavity and provide a continuous flat or convex surface in the fiber winding plane. The process can be automated by clerical or computing methods, and is repeated for each coordinate point until bridging is substantially eliminated.

Blaney, D.H.

1982-11-23

373

Effects of wind turbines on UHF television reception: field tests in Denmark, November 1991  

International Nuclear Information System (INIS)

As a result of a planning application for a wind farm comprising 20 wind turbines at Tynewydd Farm, Gilfach Goch in Mid Glamorgan, it became necessary to produce a Report discussing any detrimental effects the proposal might have on UHF television reception. In order to make that Report as definitive as possible, it was decided to carry out field tests on the exact model of wind turbine to be used to Tynewydd. This required a field trip to Denmark, and the opportunity was taken to make measurements on two other models of turbine at the same time. This Report presents the analysis of the results for all three turbines. (Author)

1992-01-01

374

Power Performance Test Report for the SWIFT Wind Turbine  

Energy Technology Data Exchange (ETDEWEB)

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

Mendoza, I.; Hur, J.

2012-12-01

375

Optimization and Reliability Problems in Structural Design of Wind Turbines  

DEFF Research Database (Denmark)

Reliability-based cost-benefit optimization formulations for wind turbines are presented. Some of the improtant aspects for stochastic modeling of loads, strengths and models uncertainties for wind turbines are described. Single wind turbines and wind turbines in wind farms with wake effects are discussed. Limit state equations are presented for fatigue limit states and for ultimate limit states with extreme wind load, and illustrated by bending failure. Illustrative examples are presented, and as a part of the results optimal reliability levels are obtained which corresponds to an annual reliability index equal to 3. An example with fatigue failure indicates that the reliability level is almost the same for single wind turbines and for wind turbines in wind farms if the wake effects are modeled equivalently in the design equation and the limit state equation.

SØrensen, John Dalsgaard

2007-01-01

376

Wind Turbine Blade with Angled Girders  

DEFF Research Database (Denmark)

The present invention relates to a reinforced blade for a wind turbine, particularly to a blade having a new arrangement of two or more girders in the blade, wherein each of the girders is connected to the upper part and the lower part of the shell and forms an angle with another girder thereby strengthening the shell against transverse shear distortion.

Jensen, Find MØlholt Technical University of Denmark,

377

Dynamic Response of Flexible Wind Turbine Blade  

Directory of Open Access Journals (Sweden)

Full Text Available Aiming at the non-stationary and stall flutter problems of wind turbine blade caused by transient load fluctuations, the dynamic properties of wind turbine were studied, the blade was simplify to a cantilever beam in case of the action of shear deformation and cross section rotating effect were considered in this analysis, equations of the blade were established based on D'Alemberts' principle and the principle of virtual displacement. The dynamic response of the wind turbine was solved by using the finite element method under the transient load environment. A 29.2 m rotor blade, previously reported in specialized literature, was chosen as a case study to validate dynamic behaviour predicted by a Timoshenko beam model. It is concluded that despite its simplicity, The cross-sectional shear-deformation  has great influence on  dynamic response of the blade.Dynamic model is sufficiently accurate to serve as a design tool for the recursive analyses required during design and optimization stages of wind turbines using only readily available computational tools.

Yu-qiao Zheng; Rong-zhen ZHAO; Hong liu

2013-01-01

378

Root region airfoil for wind turbine  

Science.gov (United States)

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); Somers, Dan M. (State College, PA)

1995-01-01

379

Applied modal analysis of wind turbine blades  

Energy Technology Data Exchange (ETDEWEB)

In this project modal analysis has been used to determine the natural frequencies, damping and the mode shapes for wind turbine blades. Different methods to measure the position and adjust the direction of the measuring points are discussed. Different equipment for mounting the accelerometers are investigated and the most suitable are chosen. Different excitation techniques are tried during experimental campaigns. After a discussion the pendulum hammer were chosen, and a new improved hammer was manufactured. Some measurement errors are investigated. The ability to repeat the measured results is investigated by repeated measurement on the same wind turbine blade. Furthermore the flexibility of the test set-up is investigated, by use of accelerometers mounted on the flexible adapter plate during the measurement campaign. One experimental campaign investigated the results obtained from a loaded and unloaded wind turbine blade. During this campaign the modal analysis are performed on a blade mounted in a horizontal and a vertical position respectively. Finally the results obtained from modal analysis carried out on a wind turbine blade are compared with results obtained from the Stig Oeyes blade{sub E}V1 program. (au)

Broen Pedersen, H.; Dahl Kristensen, O.J.

2003-02-01

380

Status of Boeing wind-turbine systems  

Energy Technology Data Exchange (ETDEWEB)

Boeing involvement with wind energy began in 1977 with the award of the US Department of Energy (DOE) sponsored MOD-2 programme to design, fabricate and install the first multimegawatt rated wind turbines developed for commercial operation. Five 2.5 MW MOD-2 turbines have been installed: three at Goldendale, Washington, one at Medicine Bow, Wyoming and in Solano County, California. These five units have operated on-line for over 4200 hours and generated over five-million kilowatt-hours of energy. The DOE MOD-5B programme to design, fabricate and install a third generation multimegawatt machine was awarded to Boeing in 1980. The MOD-5B incorporates the operational and test experience obtained with the MOD-2 test wind turbines as a great many performance improvements. These items, coupled with a continuing effort of design simplification, combine to give a wind turbine which will be highly reliable and meet the economic objectives of electric utility customers. This paper presents a summary of experiences to date with the MOD-2 machines, and the current status of the MOD-5B design.

Lowe, J.E.; Wiesner, W.

1983-12-01

 
 
 
 
381

Mod-2 wind turbine loads test correlations  

Energy Technology Data Exchange (ETDEWEB)

The Boeing Company, under contract to the Electric Power Research Institute (EPRI), has completed a test program on the Mod-2 wind turbines at Goodnoe Hills, Washington. The objectives were to update fatigue load spectra for different sites, to measure vortex generator effects, and to evaluate rotational sampling techniques. This paper presents the results of these tests and assesses the adequacy of prediction techniques.

Zimmerman, D.K.; Shipley, S.A.

1986-02-01

382

Applied modal analysis of wind turbine blades  

DEFF Research Database (Denmark)

In this project modal analysis has been used to determine the natural frequencies, damping and the mode shapes for wind turbine blades. Different methods to measure the position and adjust the direction of the measuring points are discussed. Differentequipment for mounting the accelerometers are investigated and the most suitable are chosen. Different excitation techniques are tried during experimental campaigns. After a discussion the pendulum hammer were chosen, and a new improved hammer wasmanufactured. Some measurement errors are investigated. The ability to repeat the measured results is investigated by repeated measurement on the same wind turbine blade. Furthermore the flexibility of the test set-up is investigated, by use ofaccelerometers mounted on the flexible adapter plate during the measurement campaign. One experimental campaign investigated the results obtained from a loaded and unloaded wind turbine blade. During this campaign the modal analysis are performed on ablade mounted in a horizontal and a vertical position respectively. Finally the results obtained from modal analysis carried out on a wind turbine blade are compared with results obtained from the Stig Øyes blade_EV1 program.

Pedersen, H.B.; Kristensen, O.J.D.

2003-01-01

383

Infrasound from Wind Turbines Could Affect Humans  

Science.gov (United States)

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

384

Evaluation of airfoils for small wind turbines  

Science.gov (United States)

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

385

Certification and type approval of wind turbines  

International Nuclear Information System (INIS)

Information is given on the certification and type approval of wind turbines in Europe and on the following certification bodies: CIWI-Holland (Arnhem), Det Norske Veritas (Copenhagen Denmark), The Test Station at Risoe National Laboratory (Roskilde, Denmark), and Germanischer Lloyd (Hamburg, Germany). (AB).

1994-01-01

386

Wooden wind turbine blade manufacturing process  

Energy Technology Data Exchange (ETDEWEB)

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

387

The IEC safety code for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The IEA Draft International standard - DRAFT IEC 1400-1: Wind Turbine Generator Systems, Part 1: Safety Requirements is described. A short discussion of the limited experiences so far obtained is given. Finally the future activity of the IEC/TC88 is described. (au)

Christensen, C.J.; Hjuler Jensen, P. [Risoe National Laboratory, Dept. of Meteorology and Wind Energy, The Test Station for Wind Turbines, Roskilde (Denmark)

1995-01-01

388

Load prediction of stall regulated wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Measurements of blade loads on a turbine situated in a small wind farm shows that the highest blade loads occur during operation close to the peak power i.e. when the turbine operates in the stall region. In this study the extensive experimental data base has been utilised to compare loads in selected campaigns with corresponding load predictions. The predictions are based on time domain simulations of the wind turbine structure, performed by the aeroelastic code VIDYN. In the calculations a model developed by Stig Oye were adopted in order to include the effects of dynamic stall. This paper describes the work carried out so far within the project and key results. (author)

Bjoerck, A.; Dahlberg, J.-A. [FFA, Aeronautical Research Institue (Sweden); Carlen, I. [CTH, Chalmers Univ. of Technology, Div. of Marine Structural Engineering, Goeteborg (Sweden); Ganander, H. [Teknikgruppen AB, Sollentuna (Sweden)

1996-12-31

389

Large wind turbine development in Europe  

Energy Technology Data Exchange (ETDEWEB)

During the last few years we have witnessed in Europe the development of a new generation of wind turbines ranging from 1000-1500 kW size. They are presently being tested and they are scheduled to reach the market in late 1996 early 1997. The European Commission has played a key role by funding the research leading to the development of these turbines. The most visible initiative at present is the WEGA program - the development, together with Europe`s leading wind industry players of a new generation of turbines in the MW range. By the year 1997 different European manufacturers will have introduced almost a dozen new MW machine types to the international market, half of them rated at 1.5 MW. 3 refs., 3 tabs.

Zervos, A. [Center for Renewable Energy Sources, Attikis (Greece)

1996-12-31

390

A continuous bivariate model for wind power density and wind turbine energy output estimations  

International Nuclear Information System (INIS)

[en] The wind power probability density function is useful in both the design process of a wind turbine and in the evaluation process of the wind resource available at a potential site. The continuous probability models used in the scientific literature to estimate the wind power density distribution function and wind turbine energy output assume that air density is independent of the wind speed. A constant annual value for air density of 1.225 kg m-3, corresponding to standard conditions (sea level, 15 oC), is generally used. A bivariate probability model (BPM) is presented in this paper for wind power density and wind turbine energy output estimations. This model takes into account the time variability of air density and wind speed, as well as the correlation existing between both variables. Contingency type bivariate distributions with specified marginal distributions have been used for this purpose. The proposed model is applied in this paper to meteorological data (temperature, pressure, relative humidity, wind speed) recorded over a one year period at a weather station located at the facilities of the Technological Institute of the Canary Islands (Spain). The conclusion reached is that the BPM presented in this paper is more realistic than the univariate probability models (UPMs) normally used in the scientific literature. In the particular case under study, and for all the situations analysed, the BPM has provided values for the annual mean wind power density and annual energy output of a wind turbine that fit the sample data better than the UPMs. However, as a result of the climatological characteristics of the area where the analysis was performed, the results do not differ notably from those obtained through the use of a UPM and the mean air density of the area

2007-01-01

391

A continuous bivariate model for wind power density and wind turbine energy output estimations  

Energy Technology Data Exchange (ETDEWEB)

The wind power probability density function is useful in both the design process of a wind turbine and in the evaluation process of the wind resource available at a potential site. The continuous probability models used in the scientific literature to estimate the wind power density distribution function and wind turbine energy output assume that air density is independent of the wind speed. A constant annual value for air density of 1.225 kg m{sup -3}, corresponding to standard conditions (sea level, 15{sup o}C), is generally used. A bivariate probability model (BPM) is presented in this paper for wind power density and wind turbine energy output estimations. This model takes into account the time variability of air density and wind speed, as well as the correlation existing between both variables. Contingency type bivariate distributions with specified marginal distributions have been used for this purpose. The proposed model is applied in this paper to meteorological data (temperature, pressure, relative humidity, wind speed) recorded over a one year period at a weather station located at the facilities of the Technological Institute of the Canary Islands (Spain). The conclusion reached is that the BPM presented in this paper is more realistic than the univariate probability models (UPMs) normally used in the scientific literature. In the particular case under study, and for all the situations analysed, the BPM has provided values for the annual mean wind power density and annual energy output of a wind turbine that fit the sample data better than the UPMs. However, as a result of the climatological characteristics of the area where the analysis was performed, the results do not differ notably from those obtained through the use of a UPM and the mean air density of the area. (author)

Carta, Jose Antonio [Department of Mechanical Engineering, University of Las Palmas de Gran Canaria, Campus de Tafira s/n, 35017 Las Palmas de Gran Canaria, Canary Islands (Spain); Mentado, Dunia [Department of Renewable Energies and Water, Technological Institute of the Canary Islands, Pozo Izquierdo Beach s/n, 35119 Santa Lucia, Gran Canaria, Canary Islands (Spain)

2007-02-15

392

Adaptive control algorithm for improving power capture of wind turbines in turbulent winds  

DEFF Research Database (Denmark)

The standard wind turbine (WT) control law modifies the torque applied to the generator as a quadratic function of the generator speed (K!2) while blades are positioned at some optimal pitch angle (). The value of K and should be properly selected such that energy capture is increased. In practice, the complex and time-varying aerodynamics a WT face due to turbulent winds make their determination a hard task. The selected constant parameters may maximize energy for a particular, but not all, wind regime conditions. Adaptivity can modify the controller to increase power capture under variable wind conditions. This paper present new analysis tools and an adaptive control law to increase the energy captured by a wind turbine. Due to its simplicity, it can be easily added to existing industry-standard controllers. The effectiveness of the proposed algorithm is assessed by simulations on a high-fidelity aeroelastic code.

Diaz-Guerra, Lluis; Adegas, Fabiano Daher

2012-01-01

393

Status of Atlantic Orient wind turbine technology  

Energy Technology Data Exchange (ETDEWEB)

In 1992, the Atlantic Orient Corporation installed the first AOC 15/50 50 kW turbine for field testing. Extensive field testing and analytical work were combined to produce a machine that is simple, reliable, cost effective, and in increasing demand throughout the world. Problem areas were identified and ranked according to their contribution to downtime. Specific potential solutions were conceptualized and the impact of the various solutions were evaluated on an economic and risk basis to define the benefits of each improvement. To bring the proven performance of the AOC 15/50 50 kW turbine to smaller applications the AOC 8/12 12 kW turbine was developed with variable speed operation which allows for increased energy capture as well as reduced capital cost, improved reliability, and ease of manufacture. All these factors combined will reduce the cost of energy for wind turbine applications. 7 figs.

McNamara, J.L.; Hughes, P.S.; Johnson, B.; Sherwin, R.W. [Atlantic Orient Corp., Norwich, VT (United States); Torrey, D.A. [Rensselear Polytechnic Institute, Troy, NY (United States)

1995-12-31

394

European wind turbine testing procedure developments. Task 1: Measurement method to verify wind turbine performance characteristics  

DEFF Research Database (Denmark)

There is currently significant standardisation work ongoing in the context of wind farm energy yield warranty assessment and wind turbine power performance testing. A standards maintenance team is revising the current IEC (EN) 61400-12 Ed 1 standard forwind turbine power performance testing. The standard is being divided into four documents. Two of them are drafted for evaluation and verification of complete wind farms and of individual wind turbines within wind farms. This document, and the project itdescribes, has been designed to help provide a solid technical foundation for this revised standard. The work was wide ranging and addressed 'grey' areas of knowledge, regarding existing methodologies or to carry out basic research in support offundamentally new procedures. The work has given rise to recommendations in all areas of the work, including site calibration procedures, nacelle anemometry, multi-variate regression analysis and density normalisation.

Hunter, R.; Friis Pedersen, Troels

2001-01-01

395

Evaluation of wind farm efficiency and wind turbine wakes at the Nysted offshore wind farm  

DEFF Research Database (Denmark)

Here, we quantify relationships between wind farm efficiency and wind speed, direction, turbulence and atmospheric stability using power output from the large offshore wind farm at Nysted in Denmark. Wake losses are, as expected, most strongly related to wind speed variations through the turbine thrust coefficient; with direction, atmospheric stability and turbulence as important second order effects. While the wind farm efficiency is highly dependent on the distribution of wind speeds and wind direction, it is shown that the impact of turbine spacing on wake losses and turbine efficiency can be quantified, albeit with relatively large uncertainty due to stochastic effects in the data. There is evidence of the ‘deep array effect’ in that wake losses in the centre of the wind farm are under-estimated by the wind farm model WAsP, although overall efficiency of the wind farm is well predicted due to compensating edge effects. Copyright © 2010 John Wiley & Sons, Ltd.

Barthelmie, Rebecca Jane; Jensen, L.E.

2010-01-01

396

A Shrouded Wind Turbine Generating High Output Power with Wind-lens Technology  

Directory of Open Access Journals (Sweden)

Full Text Available We have developed a new wind turbine system that consists of a diffuser shroud with a broad-ring brim at the exit periphery and a wind turbine inside it. The shrouded wind turbine with a brimmed diffuser has demonstrated power augmentation by a factor of about 2–5 compared with a bare wind turbine, for a given turbine diameter and wind speed. This is because a low-pressure region, due to a strong vortex formation behind the broad brim, draws more mass flow to the wind turbine inside the diffuser shroud.

Yuji Ohya; Takashi Karasudani

2010-01-01

397

Numerical study of turbulent flow around a wind turbine nacelle  

Energy Technology Data Exchange (ETDEWEB)

This article presents a numerical method for the simulation of turbulent flow around the nacelle of a horizontal axis wind turbine. The flow field around the turbine and nacelle is described by the Reynolds-averaged Navier-Stokes equations. The k-{epsilon} model has been chosen for closure of the time-averaged turbulent flow equations. The rotor disc is modelled using the actuator disc concept. The main purpose of this article is to assess the impacts of the variation of some operational parameters (e.g. blade pitch angle changes) and atmospheric turbulence upon the relationship between wind speed measured near the nacelle and freestream wind speed established for an isolated turbine. Simulation results were compared with experimental data (from a typical stall-controlled, commercially available wind turbine rated higher than 600 kW). In general, good qualitative agreements have been found that validate the proposed method. It has been shown that a level of accuracy sufficient for use in power performance testing can be obtained only when a proper aerodynamic analysis of the inboard non-lifting cylindrical sections of the blade is included. Furthermore, the numerical method has proven to be a useful tool for locating nacelle anemometers. (Author)

Masson, Christian; Smaili, Arezki [Ecole de Technologie Superieure, Dept. of Mechanical Engineering, Montreal, PQ (Canada)

2005-07-01

398

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

Energy Technology Data Exchange (ETDEWEB)

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

Clifton, A.

2012-12-01

399

Increasing the efficiency of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The importance of clean energy sources was realised rapidly after the negative effects of the pollution caused by generators on the environment became clear. Wind energy is a clean and renewable energy source whose applications exist worldwide. Some countries changed their national energy forward planning for renewable clean energy projects. In developed countries some researchers have worked on developing new kinds of wind turbines in order to produce a part of their power from renewable wind energy. The rotational speed of the wind blades can be increased using steering aerofoils surrounding the blades. A prototype of this wind turbine has been made in the laboratory; a ventilator whose flow rate is variable generates the 'wind'. The blade profiles are designed using the theory of aerodynamics. The steering aerofoils are fixed surrounding the wind blades at an optimum distance. The number of the aerofoils and the angle of inclination (tilt) of the foils can be changed. In the experiment the ambient conditions are held constant. Because of the optimum adjustment of the distance and angle of the aerofoils the rotational speed of the blades can be increased by 32% on the experimental device. In this paper the theoretical and experimental results will be discussed.

Varol, A. [Communications Faculty, Firat University, 23119 Elazig (Turkey); Ilkilic, C. [Technical Education Faculty, Department of Material Science, Firat University, 23119 Elazig (Turkey); Varol, Y. [Technical Education Faculty, Department of Mechanical Science, Firat University, 23119 Elazig (Turkey)

2001-07-01

400

Dfl. 150 million subsidies for Dutch wind turbine manufacturers  

Energy Technology Data Exchange (ETDEWEB)

At the 3rd National Wind Energy Conference, held in the Netherlands, 17-19 December 1985, the representative of the Dutch government announced a new program for commercialization of wind power in the Netherlands. To realize 150-200 MW wind power capacity in 1990 the government will spend Dfl. 150 million on subsidies for Dutch wind turbine manufacturers. Indicative figures for 1990 are: installation of 400 wind turbines with capacity 100 kW, 550 wind turbines in the range 200-300 kW, and 40 turbines of the 1 MW-type.

Van Beek, J.

1986-03-01

 
 
 
 
401

Minimum Thrust Load Control for Floating Wind Turbine  

DEFF Research Database (Denmark)

— Offshore wind energy capitalizes on the higher and less turbulent wind at sea. Shallow water sites are pro?table for deployment of monopile wind turbines at water depths of up to 30 meters. Beyond 30 meters, the wind is even stronger and less turbulent. At these depths, ?oating wind turbines become pro?table, capable of accessing unexploited wind resources while reaching regions of new consumers. However, ?oating wind turbines are subject