WorldWideScience
 
 
1

Wind turbines  

Energy Technology Data Exchange (ETDEWEB)

This evaluation of wind turbines is part of a series of Technology Evaluations of possible components and subsystems of community energy systems. Wind turbines, ranging in size from 200 W to 10 MW, are discussed as candidates for prime movers in community systems. Estimates of performance characteristics and cost as a function of rated capacity and rated wind speed are presented. Data concerning material requirements, environmental effects, and operating procedures also are given and are represented empirically to aid computer simulation.

Yeoman, J.C. Jr.

1978-12-01

2

Wind turbine  

Energy Technology Data Exchange (ETDEWEB)

A wind turbine is provided consisting of a cone or the frustum of a cone, on which are mounted in a more or less helical fashion , a plurality of blades having a varying pitch angle. The blades are arranged in a manner to utilize the initial force of the wind and to continue to utilize the diminishing force of the wind after it passes over the leading end of the vanes. Provided also is a shroud which enhances the wind velocity and provides a suitable diffuser augmenter to dissipate the spent wind force.

Carpenter, R.D.

1980-08-19

3

Wind turbine  

Energy Technology Data Exchange (ETDEWEB)

A wind turbine is described comprising: a vertical axis rotor assembly coupled to a rotatable drive shaft for driving electrical power generating means; first wind deflector means mounted on the wind turbine normally positioned generally upwind and to one side of the rotor assembly for initially deflecting wind current into the rotor assembly and second wind deflector means mounted on the wind turbine normally positioned on another side of the rotor assembly to redirect the initially deflected wind current into the rotor assembly. The first and second wind deflector means are normally spaced from each other by a certain inter-deflector spacing; mounting means for mounting the first and second wind deflector means in the normal positions, the mounting means including an outer shaft through which the drive shaft extends and which is normally fixed with respect thereto. The outer shaft has an upwardly facing circumferentially extending shoulder formed therein including a first shoulder portion extending around a major portion of the circumference of the outer shaft and a pair of upwardly sloping portions which reet at an apex.

Yeoman, D.R.

1987-03-24

4

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

5

Proposed procedure for the evaluation of uncertainties in load measurements on wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Subtask 3 of the project `Wind Turbine Load Measurement Instrumentation` will result in an improved knowledge of sources of uncertainties that occur during load measurements. The various sources of uncertainties all contribute to the uncertainty of the final results of the measurements. One of ECN`s tasks in the project was to draft a procedure that can be used to combine the various sources of uncertainty into the overall uncertainty of the final result. The proposed procedure is described in this report and follows the general approach laid down in the ISO-standard for expression of uncertainty in measurement. In situations where the ISO-standard fails to give a practical procedure (e.g. in case of Rain Flow Counting) an alternative procedure is described. Based on the proposed procedure some examples concerning load measurements on wind turbine blades are elaborated in detail

Van der Borg, N.J.C.M.; Van Dam, J.J.D.

1998-02-01

6

Wind turbine  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a wind turbine. It comprises: a vertical axis rotor assembly coupled to a rotatable drive shaft for driving electrical power generating means; first wind deflector means for initially reflecting wind current into the rotor assembly; second wind deflector means to redirect the initially deflected wind current into the rotor assembly; and mounting means for mounting the first and second wind deflector means in the normal positions. The mounting means including an outer shaft through which the drive shaft extends and which is normally fixed with respect thereto. The outer shaft having at least one lower groove winding in one of a left-hand or right-hand direction, at least one lower groove constituting a first lower groove set, and at least one upper groove winding in the other of the left-hand or right-hand direction, at least one upper groove constituting a second upper groove set, and first lower and second upper connector rings coupled to the first and second wind deflector means respectively, and mounted on the outer shaft proximate to the first and second groove sets respectively. The first and second connector rings including guide means cooperating with at least one groove of the first and second groove sets respectively. The mounting means allowing at least one of the first and second wind deflector means to automatically move relative to each other and from its respective normal position when the velocity of the wind current exceeds a first predetermined value to increase the inter-deflector spacing and causing at least one of the first and second wind deflector means to automatically return to its respective normal position when the velocity of the wind current diminishes to a value below the first predetermined value.

Yeoman, D.R.

1989-07-25

7

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

8

Wind turbines; Aerogenerateurs electriques  

Energy Technology Data Exchange (ETDEWEB)

This article describes the electrotechnical aspects of wind turbines, in particular with respect to other power generation systems: 1 - context and evolution prospects of wind energy; 2 - wind turbines: wind characterization, energy efficiency of a 'wind catcher', different types of wind turbines, energy conversion adjustment means; 3 - wind turbine systems: main design criteria and constraints, wind turbine systems architecture; 4 - specificity of wind power generators: asynchronous and synchronous generators. (J.S.)

Multon, B.; Ben Ahmed, H. [Ecole Nationale Superieure de Cachan/Satie, 94 (France); Roboam, X. [Centre National de la Recherche Scientifique (CNRS/LEEI/UMR), (CNRS/INPT/ENSEEIHT), 31 - Toulouse (France); Dakyo, B.; Nichita, C. [Groupe de Recherche en Electrotechnique et Automatique du Havre, Lab. GREAH EA 3220, 76 (France); Gergaud, O. [Institut Universitaire de Technologie, 35 - Rennes (France)

2005-01-01

9

Recommended practices for wind turbine performance testing. Preliminary proposals for sub-section on wind speed/power measurements  

Energy Technology Data Exchange (ETDEWEB)

In the present paper some proposals as to the contents of the ''recommended practices'' are put forward. The paper shall be considered as a first draft, incomplete in many places, but hopefully sufficient as a basis for detailed discussions. The present proposals consider primarily long term measurements, which should give the most accurate information for the above-mentioned users. Additional recommendations, when making short term measurements, are thus left out for the present. What is discussed are the methods to be used in determining - the power curve of a wind turbine. - the mean power output or annual energy production. - the percentage of time in which the turbine is operating or the power duration curve.

Frandsen, S. (Risoe National Laboratory, Roskilde, Denmark); Maribo Pedersen, B. (Technical University of Denmark, Lyngby, Denmark); Frandsen, S. (ed.)

1981-04-01

10

Wind turbines  

Energy Technology Data Exchange (ETDEWEB)

A wind turbine is disclosed having a generally vertically extending support tower upon which are mounted a front or blade section and a rear or tail section. The front section includes a generally horizontal drive shaft which is connected to a vertical drive shaft in the support tower. The rear or tail section is rotatably mounted on the support structure to permit radial oscillation of the tail section. The blade and tail section are releasably interconnected to each other such that upon manual operation of a latch, the rear or tail section can pivot independently from the front or blade section. The front section is upwardly inclined relative to the rear section whereby a universal joint is provided in the vertical drive shaft to insure that a portion of the vertical drive shaft remains perpendicular to the horizontal drive shaft connected to the front or blade section.

Skelskey, D.A.

1983-09-13

11

Locking the wind turbines  

Energy Technology Data Exchange (ETDEWEB)

With the new technology called 'Sealock', the Norwegian company Vest Kran Wind Power enters the offshore wind turbine market. 'Sealock' enhances the mounting and maintenance for wind turbines offshore. (Author)

Oekland, John

2009-07-01

12

Wind turbine noise diagnostics  

International Nuclear Information System (INIS)

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.

2009-05-19

13

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

14

Turbulence and Wind Turbines  

Energy Technology Data Exchange (ETDEWEB)

The nature of turbulent flow towards, near and behind a wind turbine, the effect of turbulence on the electricity production and the mechanical loading of individual and clustered wind turbines, and some future issues are discussed.

Brand, A.J. [ECN Wind Energy, Petten (Netherlands); Peinke, J. [ForWind, Institute of Physics, University of Oldenburg, Oldenburg (Germany); Mann, J. [Risoe National Laboratory for Sustainable Energy, Technical University of Denmark, Wind Energy Division, Roskilde (Denmark)

2011-09-15

15

Turbulence and wind turbines  

International Nuclear Information System (INIS)

The nature of turbulent flow towards, near and behind a wind turbine, the effect of turbulence on the electricity production and the mechanical loading of individual and clustered wind turbines, and some future issues are discussed.

2011-12-22

16

Small wind turbines  

CERN Document Server

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

17

Aerodynamics of wind turbines  

CERN Multimedia

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

18

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

19

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

20

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 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 ...

Schubel, Peter J.; Crossley, Richard J.

2012-01-01

 
 
 
 
21

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.

Richard J. Crossley

2012-09-01

22

Wind Turbine Power References in Coordinated Control of Wind Farms  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The new grid regulations require that a grid-connected wind farm acts as a single controllable power producer. To meet this requirement a traditional wind farm control structure, which allowed individual wind turbines to internally define their power production, has to be modified. This paper investigates the opportunity for wind turbine load reduction that arises from dynamic power control of wind turbines. The wind farm controller design is proposed that utilizes coordinated power control o...

Spudic, Vedrana; Jelavic, Mate; Baotic, Mato

2011-01-01

23

Wind turbines modelling  

Energy Technology Data Exchange (ETDEWEB)

Experimental identification in relation to wind turbines modelling is introduced. Such a model is complex because of the rapid variability of wind parameters and the constructive elasticity of the modern wind turbine. The model is required to simulated specific regimes, it helps in optimizing design and the control equipment. The modern adaptive control concept (on-line modelling), the basic mathematical techniques and how the wind conditions are included in the modelling, are dealt with. The author's software is presented and some results found in relevant literature related to both analytical and experimental models for medium and large wind turbines are given. (AB).

Tantareaunu, C.

1992-06-01

24

Dynamic control of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The paper presents an intelligent wind turbine control system based on models integrating the following three approaches: data mining, model predictive control, and evolutionary computation. To enhance the control strategy of the intelligent system, a multi-objective model is proposed. The model involves five different objectives with different weights controlling the wind turbine performance. These weights are adjusted in response to the variable wind conditions and operational requirements. Three control factors, wind speed, turbulence intensity, and electricity demand are considered in eight computational scenarios. The performance of each scenario is illustrated with numerical results. (author)

Kusiak, Andrew; Li, Wenyan; Song, Zhe [Department of Mechanical and Industrial Engineering, 3131 Seamans Center, The University of Iowa, Iowa City, IA 52242-1527 (United States)

2010-02-15

25

Introduction to wind turbine engineering  

Energy Technology Data Exchange (ETDEWEB)

Analytical techniques and engineering procedures concerning wind turbines are presented. Data in graphical form and methods for estimating the cost of energy derived from wind energy systems are provided. Topics considered include the applications of wind power, ideal windmill performance, geographical wind distributions, vertical wind speed gradient, propeller turbines, vertical axis lifting surface turbines, drag-type turbines, and preliminary design procedures. 48 references.

Wortman, A.J.

1983-01-01

26

Wind turbines: product guide  

Energy Technology Data Exchange (ETDEWEB)

A product guide is given for wind turbines produced by fifty manufacturers all around the world. For each wind turbine details are given of the model number, the type and the specifications of the rotor, the blades, the tower, the drive and the generator. (U.K.).

1988-09-01

27

Aerodynamics of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Twenty three papers presented by participants at the 8th symposium on Aerodynamics of Wind Turbines held in Lyngby (Denmark) on November 21-22 1994 under the implementing agreement for cooperation in the research and development of wind turbine systems Annex XI (International Energy Agency. IEA Joint Action). (AB)

Maribo Pedersen, B. [ed., Technical University of Denmark. Dept. of Fluid Mechanics, Lyngby (Denmark)

1994-12-31

28

Wind turbines at work  

Energy Technology Data Exchange (ETDEWEB)

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

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

1982-08-01

29

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

30

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

31

Wind turbine wake meandering  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this master thesis the meandering of the wake of a three bladed horizontal axis model wind turbine has been studied. Measurements have been conducted by the use of four hot-wire probes located at multiple nearby points in the wake at X/D = 1, 3 and 5 downstream the model wind turbine. The meandering has been studied based on the location of the tip vortices shed by the turbine blades. The experiments were conducted in the wind tunnel at NTNU at the Department of Energy and Process Engineer...

Lynum, Susanne

2013-01-01

32

Testing of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The certification of wind turbines is important for granting licenses for the construction of wind turbines. Within five and a half years the Netherlands Energy Research Foundation ECN gained a lot of experience in testing wind turbines on the test field in Petten and other sites. During these years the testing method has been improved and the 'type assessment' in the early eighties has been extended to a formal certificate investigation. For the future another extension of this investigation can be expected so that testing methods and instrumentation have to be adjusted. 3 figs., 2 tabs.

Beurskens, H.J.; Lindhout, A.H.; Stam, W.J.

1988-12-01

33

An integrated modeling method for wind turbines  

Science.gov (United States)

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

Fadaeinedjad, Roohollah

34

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

35

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

36

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

37

Wind turbines in competition  

Energy Technology Data Exchange (ETDEWEB)

A wind turbine evaluation centre in the west of Britain provides the battlefield in which manufacturers will joust for contracts to equip the UK's and other countries' forthcoming wind farms. The choice of turbine generators for the three wind farms that the UK electricity supply industry plans to have at work in the early 1990s will depend on evaluations at the Wind Energy Demonstration Centre recently opened by the Central Electricity Generating Board (CEGB) at Carmarthen Bay, Wales.

Conway, A.

1988-12-01

38

Wind Turbine Blade Design  

Science.gov (United States)

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

Project, Kidwind

2006-01-01

39

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

40

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

 
 
 
 
41

Wind turbines and health  

Energy Technology Data Exchange (ETDEWEB)

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.

Rideout, K.; Copes, R.; Bos, C. [National Colaborating Centre for Environmental Health, Vancouver, BC (Canada)

2010-01-15

42

Wind turbine design  

Energy Technology Data Exchange (ETDEWEB)

The design agency Jones Garrard were commissioned by ETSU to identify and demonstrate the effectiveness of good industrial design upon wind turbines. As part of this study Martin Hamblin, an independent research agency were commissioned by the Central Office of Information to validate the benefits of the industrial design upon the views and attitudes of professional and interest groups and the general public. The objectives of this research were: To clarify the criteria upon which the effectiveness of wind turbine design should be measured. To evaluate the differences between selected wind turbine designs in terms of their visual impact upon the general public perceptions of wind farms and the wind energy industry. To assess the role and impact of industrial design upon perceptions and attitudes of key professional and interest groups. (Author)

NONE

1997-10-01

43

A wind turbine  

Energy Technology Data Exchange (ETDEWEB)

A wind turbine is described comprising a horizontal axis mounted on a stand. Rotatably mounted around the axle is a core carrying sixteen flat blades staggered along and radially about the core. The axle projects at one end and is connected to an electric generator; the other end of the axle is connected to a bladed fly wheel. A curved deflector plate extends downwards from a horizontal plane passing through the axle downwards underneath the turbine blades to a vertical plane passing through the axle. Running horizontally along the upper edge of the deflector is a deflector strip which deflects wind flow upwards against the turbine blades. (3 figures). (author)

Newton de Zoysa, G.

1993-08-08

44

Upgrading conventional wind turbines  

Energy Technology Data Exchange (ETDEWEB)

When approaching a conventional wind turbine, the air flow is slowed down and widened. This effect causes a loss in the efficiency of the turbine. By creating a field of low pressure behind the turbine, this effect and the corresponding loss in efficiency can be avoided. In order to maintain this low pressure field, the air passing near, but not through the turbine needs to do work. Based on these considerations we have made a model of a wind turbine with a wing profiled ring around it. We present various fluidodynamical calculations in order to study the resulting increase in power and in order to estimate what the geometrical size of such an apparatus would need to be and whether it could be of advantage compared to conventional devices from an economic point of view. (author)

Bet, F. [BMW Research Center, Muenchen (Germany); Grassmann, H. [University of Udine (Italy). Dept. of Physics

2003-01-01

45

Alcoa wind turbines  

Science.gov (United States)

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

Ai, D. K.

1979-01-01

46

Wind turbine state estimation  

DEFF Research Database (Denmark)

Dynamic inflow is an effect which is normally not included in the models used for wind turbine control design. Therefore, potential improvement from including this effect exists. The objective in this project is to improve the methods previously developed for this and especially to verify the results using full-scale wind turbine data. The previously developed methods were based on extended Kalman filtering. This method has several drawback compared to unscented Kalman filtering which has therefore been developed. The unscented Kalman filter was first tested on linear and non-linear test cases which was successful. Then the estimation of a wind turbine state including dynamic inflow was tested on a simulated NREL 5MW turbine was performed. This worked perfectly with wind speeds from low to nominal wind speed as the output prediction errors where white. In high wind where the pitch actuator was always active the results where not as convincing because the output prediction errors where not white. Usingreal data it has not been possible to get really good results so far. There remains a number of challenges: verifying turbine parameters and getting the most suitable measurement signals, including the 3P effect in the model and perhaps including the 1P effect. It is obviously difficult to make a final conclusion before the above challenges has been resolved.

Knudsen, Torben

2014-01-01

47

Floating wind turbine system  

Science.gov (United States)

A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.

Viterna, Larry A. (Inventor)

2009-01-01

48

Wind turbine operated sailboat  

Energy Technology Data Exchange (ETDEWEB)

A wind powered boat is disclosed which incorporates a vertical axis rotary turbine. A shaft portion extends downwardly from the turbine to a water pump, with the boat being provided with a forwardly opening inlet and a rearwardly opening outlet from the water pump. When rotating, the turbine operates the pump by the shaft to draw in water through the inlet, thereby creating a low pressure area in front of the boat, and to force the water out through the outlet for propelling the boat. In a preferred embodiment, the boat has a catamaran construction or is a large ocean going vessel with enough width to provide a buffer to either side of the turbine, and the turbine is the Darrieus rotor type. The pump is a standard centrifugal type of pump. A self adjusting braking device for the turbine is also disclosed, which prevents over-rotation and is also capable of storing heat energy generated during braking. 4 figs.

Hall, R.

1990-07-31

49

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

50

Wind Turbine Acoustics  

Science.gov (United States)

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

Hubbard, Harvey H.; Shepherd, Kevin P.

2009-01-01

51

WEGA - large wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Based on the results of research projects carried out in the framework of a programme supported by the Commission of the European Communities, this book presents the latest achievements of wind energy technology, in particular of large wind turbines in the megawatt power range. The WEGA (WEGA is an acronym for the German 'Wind Energie Gross Anlagen') programme is an excellent example of European cooperation in the field of technology of innovative energy systems. (orig.) With 115 figs.

Hau, E.; Langenbrinck, J. (ETAPLAN, Ingenieurbuero fuer Energietechnische Analysen und Planung GmbH, Muenchen (Germany)); Palz, W. (Commission of the European Communities, Brussels (Belgium). Directorate General 12 for Science, Research and Development)

1993-01-01

52

Dermond wind turbine  

Energy Technology Data Exchange (ETDEWEB)

Dermond Inc. has developed a simplified and improved VAWT technology that will solve problems encountered by wind turbines. The new design improves energy efficiency and performance in electricity generation. Dermond Inc. is a wholly owned Canadian subsidiary of McKenzie Bay International Ltd. The company plans to manufacture and sell its turbines and establish itself as a dominant player in the renewable energy market. Three 75 kW prototypes are currently under construction for installation in the North American Arctic, oceanside areas, and urban rooftops. Dermond Wind Turbine markets include off-grid and remote areas which currently rely on diesel generators. In main grid areas, Dermond Wind Turbines can be installed on vacant lands or on roofs, thereby eliminating the need for transmission lines. The technology can be used by industries and building owners to reduce power costs. Initial sales and marketing efforts will be for off-grid installation of turbines that are less than 500 kW. Dermond Inc. has created strategic alliances with W.M Bradley Manufacture, Universite du Quebec en Abitibi-Temiscamingue, and Ptarmigan Off-Grid Power Inc. The first commercial sale of the 75 kW wind turbine is expected for Fall 2004. 1 tab., 1 fig.

NONE

2003-07-01

53

Vertical axis wind turbines  

Energy Technology Data Exchange (ETDEWEB)

A vertical axis wind turbine has one or more blades mounted in cantilever manner on a hub on a short tower. The or each blade is unsupported above the level of the hub and extends freely upwards. The hub may be a rigid mounting or a pivot mounting. If two blades are used, they are desirably arranged in a crossed configuration so as to extend along a common axis. The upward arm of the blade can be straight and rigid, or flexible, or cranked, or curved. The wind turbine is suitable both for land-based use and on water-going craft.

Taylor, D. A. (GB)

1985-12-31

54

Superconducting wind turbine generators  

DEFF Research Database (Denmark)

A HTS machine could be a way to address some of the technical barriers offshore wind energy is about to face. Due to the superior power density of HTS machines, this technology could become a milestone on which many, including the wind industry, will rely on in the future. The work presented in this thesis is a part of a larger endeavor, the Superwind project that focused on identifying the potentials that HTS machines could offer to the wind industry and addressing some of the challenges in the process. In order to identify these challenges, I have designed and constructed an HTS machine experimental setup which is made to serve as precursor, leading towards an optimized HTS machine concept proposed for wind turbines. In part, the work presented in this thesis will focus on the description of the experimental setup and reasoning behind the choices made during the design. The setup comprises an HTS synchronous machine where a revolv- ing armature winding spins around an open bath liquid nitrogen cryostat, which contains the HTS coils cooled down to 77 K. A significant part of the thesis is allocated to the description of the setup, particularly the torque transfer element and the compact cryostat design, where a concept with 20 W of heat transfer is achieved. Following the setup description, the focus turns to the electromagnetic design of the HTS machine. Particularly, an approach to increase the performance of HTS coils and the influence of the armature reaction to the HTS field winding will be discussed. Two design strategies are proposed, novel in a machine design, in order to reduce the amount of HTS required in a machine whereby the merits of both have been experimentally verified. The first employs a multiple HTS types in the machine design, since each type of the HTS tape has a specific magnetic characteristic with respect to the critical current. I have showed that the potential for the reduction of HTS conductor can be significant, if the coils are placed strategically, whereby the coils wound with BSCCO performed 40% better depending on the placement in the field winding. The 2G coils were less sensitive to the placement which made them particularly useful for high magnetic field regions in the eld winding. The second design approach proposed and tested was to use multiple current supplies which allowed each coil to operate close to its critical current. I have demonstrated that by introducing one additional power supply, an order of 12% higher MMF was generated (or equivalent HTS savings achieved). Increasing in the number of additional power supplies did not show the same potential for HTS reduction. The implications of an armature reaction impact on the HTS field Winding performance were examined and veried throughout a series of Locked Armature experiments. The interaction have been dened in the terms of two (direct and quadrature) axis machine theory (Park transformation), where significant reduction of 20% was observed for the rated armature reaction in the q axis. Building on this observation,a control strategy for the excitation current to improve a partial load eciency of a HTS machine is proposed. Thus, this work has shown that a signicant savings of a the costly HTS tape could be realized indicating that the HTS machine design can still be optimized towards more competitive alternative to conventional machines. Additionally, by constructing the HTS machine setup we went through most of the issues related to the HTS machine design which we managed to address in rather simple manner using everyday materials and therefore proving that HTS machines are close to commercialization.

Mijatovic, Nenad

2014-01-01

55

Superconducting Wind Turbine Generators  

DEFF Research Database (Denmark)

A HTS machine could be a way to address some of the technical barriers offshore wind energy is about to face. Due to the superior power density of HTS machines, this technology could become a milestone on which many, including the wind industry, will rely in the future. The work presented in this thesis is a part of a larger endeavor, the Superwind project that focused on identifying the potentials that HTS machines could offer to the wind industry and addressing some of the challenges in the process. In order to identify these challenges, I have design and constructed a HTS machine experimental setup which is made to serve as precursor, leading towards an optimized HTS machine concept proposed for wind turbines. In part, the work presented in this thesis will focus on the description of the experimental setup and reasoning behind the choices made during the design. The setup comprises from a HTS synchronous machine where a revolving armature winding spins around an open bath liquid nitrogen cryostat, which contains the HTS coils cooled down to 77 K. A significant part of the thesis is allocated to the description of the setup, particularly the torque transfer element and the compact cryostat design, where a concept with ~20 W of heat transfer is achieved. Following the setup description, the focus turns to the electromagnetic design consideration of the HTS machine. Particularly, an approach to increase the performance of HTS coils and the influence of the armature reaction to the HTS field winding will be discussed. Two design strategies are proposed, novel in a machine design, in order to reduce the amount of HTS required in a machine whereby the merits of both have been experimentally verified. The first employs a multiple HTS types in the machine design, since each type of the HTS tape has a specific magnetic characteristic with respect to the critical current. I have showed that the potential for the reduction of HTS conductor can be significant, if the coils are placed strategically, whereby the coils wound with BSCCO performed 40% better depending on the placement in the field winding. The 2G coils were less sensitive to the placement which made them particularly useful for high magnetic field regions in the field winding. The second design approach proposed and tested was to use multiple current supplies which allowed each coil to operate close to its critical current. I have demonstrated that by introducing one additional power supply, an order of 12% higher MMF was generated (or equivalent HTS savings achieved). Increasing in the number of additional power supplies did not show the same potential for HTS reduction. The implications of an armature reaction impact on the HTS field winding performance were examined and verified throughout a series of Locked Armature experiments. The interaction have been defined in the terms of two (direct and quadrature) axis machine theory (Park transformation), where significant reduction of ~ 20% was observed for the rated armature reaction in the q axis. Building on this observation, a control strategy for the excitation current to improve a partial load eciency of a HTS machine is proposed. Thus, this work has shown that a significant savings of a the costly HTS tape could be realized indicating that the HTS machine design can still be optimized towards more competitive alternative to conventional machines. Additionally, by constructing the HTS machine setup we went through most of the issues related to the HTS machine design which we managed to address in rather simple manner using everyday materials and therefore proving that HTS machines are close to commercialization.

Mijatovic, Nenad

2012-01-01

56

Predicting Noise From Wind Turbines  

Science.gov (United States)

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

Grosveld, Ferdinand W.

1990-01-01

57

Wind turbine with damper  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a horizontal axis wind turbine assembly comprising: a rotor assembly having delta wing blades; a head assembly secured at one end to the rotor assembly and being mountable on a tower so as to pivot about a vertical yaw axis; a tail assembly pivotally mounted on the other end of the head assembly, so as to pivot about a vertical axis, the assembly having one or more upstanding tail surfaces which cooperate with the wind to cause the assembly to track the wind; the central axis of the rotor assembly being offset from the vertical plane of the yaw axis; A wind force acting on the blades will generate a moment about the yaw axis; moment urges the rotor assembly to pivot from an operative position, transverse to the wind, toward a feathered position, edgeways to the wind flow; the tail assembly continues to track the wind; means, connected with the head assembly, for applying a counterbalancing counter-rotational moment to the head assembly to resist the wind moment; a container, mounted in the wind turbine assembly, for containing a reservoir of hydraulic fluid; a double-acting cylinder being pivotally connected with the head and tail assemblies so as to resist pivoting movement of the head assembly about the yaw axis; hydraulic fluid lines interconnecting the reservoir and the two ends of the cylinder chamber; and means for controlling the rate of fluid movement through each of the lines.

Kenfield, J.A.C.

1987-06-23

58

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

59

Wind turbine design  

International Nuclear Information System (INIS)

Using wind energy to generate power has become an attractive and feasible possibility as a complement to the traditional power generation methods. This is mainly due to advances in aerodynamic analysis, development of new composite materials and the experience gained through innovative and pioneering designs. Wind energy is abundant and inexhaustible. Its use to generate power in remote areas of developing countries with less developed infrastructure could accelerate the modernisation of such regions. This paper attempts to give an overview of the technical aspects of wind turbine design and is meant for an audience new to the subject. It is not the purpose of this presentation to deal in detail with the technical aspects, but rather to highlight the salient aspects of the design. After a brief introduction, the topics covered are aerodynamics and aeroacoustics of wind turbines with a discussion of the structural dynamics and vibration engineering aspects. (author)

2001-01-01

60

Noise from wind turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A rapid growth of installed wind power capacity is expectedin the next few years. However, the siting of wind turbines ona large scale raises concerns about their environmental impact,notably with respect to noise. To this end, variable speed windturbines offer a promising solution for applications in denselypopulated areas like the European countries, as this designwould enable an efficient utilisation of the masking effect dueto ambient noise. In rural and recreational areas where windturbi...

Fe?geant, Olivier

2001-01-01

 
 
 
 
61

Vision on Mini Wind Turbines  

International Nuclear Information System (INIS)

This document sketches the vision of the Netherlands Wind Energy Association (NWEA) with respect to the options for implementing small wind turbines in the Netherlands. Next to a description of the characteristics of mini turbines, mini turbines are compared to large wind turbines and solar panels and unique opportunities for mini turbines are described. Next, the market is described as well as the bottlenecks and their solutions. Finally ongoing projects with mini turbines are described, an estimate is provided for the potential for mini turbines and the ambitions are discussed as well as the recommended action plan.

2009-01-01

62

Tornado type wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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, Ch.-T.

1984-06-05

63

Tornado type wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

64

Output of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

27 Smaller wind turbines installed in the Netherlands are listed with following data: owner, location, producer, rotor diameter, output during June, July and total output till August. This list is far from complete. Some sixty windmills have been constructed in the Netherlands.

Werkhoven, J.; de Bruijne, R.

1982-09-01

65

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

66

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

67

Rotating transformers in wind turbine applications  

Energy Technology Data Exchange (ETDEWEB)

The power consumption of rotating electrical components is often supplied via slip-rings in wind turbines. Slip-ring equipment is expensive and need maintenance and are prone to malfunction. If the slip-rings could be replaced with contact-less equipment better turbines could be designed. This paper presents the design, some FE calculations and some measurements on a prototype rotating transformer. The proposed transformer consists of a secondary rotating winding an a stationary exciting primary winding. The results indicate that this transformer could be used to replace slip-rings in wind turbines. (Author)

Hylander, J. [Chalmers Univ. of Technology, Goeteborg (Sweden); Engstroem, S. [Aegir konsult AB, Lidingoe (Sweden)

1996-12-31

68

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

69

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

70

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.

Shun-Yu Chan

2013-03-01

71

Vertical axis wind turbines  

Energy Technology Data Exchange (ETDEWEB)

In a straight-bladed vertical axis wind turbine, a turbine blade is usually mounted at the outer end of a horizontal arm which interconnects the blade with the vertical rotor. In the invention described, the turbine blade is connected to the vertical rotor by a pair of vertically spaced arms, each of aerofoil shape in lateral cross-section. The arms are inclined in opposite directions relative to the horizontal to form a truss-like structure. During rotation these generate additional energy forces which are transmitted to the rotor to assist in rotating it. Preferably, the upper arm is downwardly inclined from its point of connection with the rotor and the lower arm upwardly inclined. (UK).

Sutton-Vane, Vane.

1992-04-29

72

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

73

Small Wind Turbine Technology Assessment.  

Science.gov (United States)

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

F. Avia Aranda I. Cruz Cruz

1999-01-01

74

Concept testing of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The Danish certification system for wind turbines has requirements to testing of wind turbines which is described as basic and system testing. It has been the practice in the past few years that the loads on the 500 kW wind turbine generation were verified for each wind turbine type by measurements, which has meant system testing of quite a number of wind turbines. Therefore, it was decided to put up a testing program that incorporates calculations with aeroelastic codes into the certification process. The present paper describes a testing procedure, called concept testing, which is based on the applicability of aeroelastic codes to reduce the number of system tests necessary to perform on wind turbines of the same concept. (au)

Paulsen, U.S.; Larsen, G.C.; Petersen, S.M.; Pedersen, T.F. [Risoe National Lab., The Test Station for Wind Turbines, Roskilde (Denmark)

1995-01-01

75

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

76

Reliability analysis for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Modern wind turbines are complex aerodynamic, mechanical and electrical machines incorporating sophisticated control systems. Wind turbines have been erected in increasing numbers in Europe, the USA and elsewhere. In Europe, Germany and Denmark have played a particularly prominent part in developing the technology, and both countries have installed large numbers of turbines. This article is concerned with understanding the historic reliability of modern wind turbines. The prime objective of the work is to extract information from existing data so that the reliability of large wind turbines can be predicted, particularly when installed offshore in the future. The article uses data collected from the Windstats survey to analyse the reliability of wind turbine components from historic German and Danish data. Windstats data have characteristics common to practical reliability surveys; for example, the number of failures is collected for each interval but the number of turbines varies in each interval. In this article, the authors use reliability analysis methods which are not only applicable to wind turbines but relate to any repairable system. Particular care is taken to compare results from the two populations to consider the validity of the data. The main purpose of the article is to discuss the practical methods of predicting large-wind-turbine reliability using grouped survey data from Windstats and to show how turbine design, turbine configuration, time, weather and possibly maintenance can affect the extracted results. (Author).

Tavner, P. J. [New and Renewable Energy Group, School of Engineering, Durham University, Durham DH1 4RL, (United Kingdom); Xiang, J. [CREST, Loughborough University, Loughborough, (United Kingdom); Spinato, F. [New and Renewable Energy Group, School of Engineering, Durham University, Durham DH1 4RL, (United Kingdom)

2006-07-12

77

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

78

Equivalent models of wind farms by using aggregated wind turbines and equivalent winds  

International Nuclear Information System (INIS)

As a result of the increasing wind farms penetration on power systems, the wind farms begin to influence power system, and therefore the modeling of wind farms has become an interesting research topic. In this paper, new equivalent models of wind farms equipped with wind turbines based on squirrel-cage induction generators and doubly-fed induction generators are proposed to represent the collective behavior on large power systems simulations, instead of using a complete model of wind farms where all the wind turbines are modeled. The models proposed here are based on aggregating wind turbines into an equivalent wind turbine which receives an equivalent wind of the ones incident on the aggregated wind turbines. The equivalent wind turbine presents re-scaled power capacity and the same complete model as the individual wind turbines, which supposes the main feature of the present equivalent models. Two equivalent winds are evaluated in this work: (1) the average wind from the ones incident on the aggregated wind turbines with similar winds, and (2) an equivalent incoming wind derived from the power curve and the wind incident on each wind turbine. The effectiveness of the equivalent models to represent the collective response of the wind farm at the point of common coupling to grid is demonstrated by comparison with the wind farm response obtained from the detailed model during power system dynamic simulations, such as wind fluctuations and a grid disturbance. The present models can be used for grid integration studies of large power system with an important reduction of the model order and the computation time

2009-03-01

79

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

80

New high profitable wind turbines  

Energy Technology Data Exchange (ETDEWEB)

To generate more quantities of electric energy from wind it is necessary to use a new type of wind turbine built in the regulable mantle's nozzle. This wind turbine type replaces the free air stream from wind by a programmed, i.e. regulated, and partially concentrated stream of air. The nozzle shell is designed as an aerodynamically shaped ring with wings with its lower pressure side pointed towards the centre so that the lift force on each part of the wing is directed radially towards the centre. This induces centrifugal reaction force in the airflow that causes the stream field to expand strongly downstream of the rotor and includes a greater number of streamlines in the active stream in front of the rotor (upstream). Thus the nozzle forces a higher mass flow rate of air through the turbine. The higher mass flow and higher velocity reduction behind the rotor result in a higher energy output from the wind turbine in the nozzle. In this way the wind turbine efficiency is multiplied. New turbines induce more power from weaker and medium winds and their lasting time, because of the relation p = f(v{sup 3}) (i.e. the power corresponds to wind velocity raised to third power). Wind turbine nozzle produces three times more energy than conventional wind turbine. Short economic analysis for conditions of the island of Lastovo indicates that profit gained by new turbines is up to five times higher than by conventional turbines. The new wind turbine nozzle should generate interest and demand on an international market, even for regions with weaker winds. (Author)

Frankovic, Bernard [Rijeka Univ., Faculty of Engineering, Rijeka (Croatia); Vrsalovic, Ivan [Rijekaprojekt d.o.o., Rijeka (Croatia)

2001-11-01

 
 
 
 
81

Superconducting wind turbine generators  

Science.gov (United States)

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

Abrahamsen, A. B.; Mijatovic, N.; Seiler, E.; Zirngibl, T.; Trćholt, C.; Nřrgĺrd, P. B.; Pedersen, N. F.; Andersen, N. H.; Řstergĺrd, J.

2010-03-01

82

Wind turbine control: Robust model based approach  

Energy Technology Data Exchange (ETDEWEB)

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. (Author)

Mirzaei, M.

2012-07-01

83

Wind resource assessment and loss factors for small wind turbines  

Energy Technology Data Exchange (ETDEWEB)

A wind resource assessment is used to characterize wind flow at a particular site and estimate the annual energy production of a proposed installation. The energy production of a turbine is affected by many sources of loss and uncertainty, including high levels of turbulence. The City of Waterloo and the Region of Waterloo commissioned the University of Waterloo's Wind Energy Group to study the feasibility of wind power in the Waterloo region where 2 towers were recently installed. A preliminary examination of meteorological data suggests that these areas are suitable for small wind turbines. However, the wind energy potential is greater at one site (WRESTRC) than at the other (RIM Park), due to stronger and steadier winds, as well as a higher estimated power production from a generic 50 kW turbine. 10 refs., 8 tabs., 10 figs.

Lam, V.; Johnson, D.A. [Waterloo Univ., ON (Canada). Dept. of Mechanical and Mechatronics Engineering, Wind Energy Group

2010-07-01

84

Control strategies for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Operating a wind turbine at variable rotor speed can confer several advantages, foremost among them being enhanced energy capture. Computer simulation and field experiments with a 5 m diameter turbine are in agreement in demonstrating this. Small turbines will benefit most from such a flexible control strategy.

Wilmshurst, S.M.B.

1988-01-01

85

Dynamic behavior of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The dynamic response of wind turbines was calculated, and the dynamic stability was investigated. Methods to calculate the dynamic behavior are discussed. The analysis of the dynamic behavior produces the eigenfrequencies of the turbine construction as a function of the rotor speed in order to avoid eigenfrequencies coinciding with frequencies of exciting loads. The dynamic analysis also shows if the turbines motions are damped allowing the stability of the turbine design to be determined. (ESA)

Ottens, H.H.

1983-08-01

86

Grid-connected wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Fifteen projects presented at a contractors' meeting on wind energy are reviewed and cover a wind farm in Denmark, a 17m diameter vertical axis turbine, a cost effective 1MW wind turbine and island projects e.g. M30 project in Sardinia. Connection of a 100 kW wind turbine to the Irish network, testing of a 200 kW WEC, electricity production for a water purification plant, and hydraulic transmission are discussed. Design, siting, control, safety, operation, performance and economics are considered. (U.K.).

Nacfaire, H.

1988-01-01

87

The small wind turbine field lab  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The emerging market of small wind turbines (SWT) is characterised by a large variety of turbine types as well as turbine performance. The abundance of more ‘exotic’ types of vertical axis wind turbines (VAWT) next to the more traditional horizontal axis wind turbines (HAWT) shows that this market is still developing. However, some technologies have proven to possess the same potential typically only found in larger wind turbines. To study the (lack of) performance of current small wind tu...

Laveyne, Joannes; Wyngene, Karel; Kooning, Jeroen; Ackere, Samuel; Eetvelde, Greet; Vandevelde, Lieven

2013-01-01

88

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

89

Online wind turbine measurement laboratory  

DEFF Research Database (Denmark)

As part of the International Master of Science Program in Wind Energy at DTU, a complete interactive wind turbine measurement laboratory has been developed. A 500 kW stall regulated wind turbine has been instrumented with sensors for recording 1) turbine operational parameters, 2) meteorological conditions, 3) electrical quantities and 4) mechanical loads in terms of strain gauge signals. The data acquisition system has been designed and implemented by Risø together with students and teachers from DTU. It is based on LabVIEW© combined with a MySQL database for data management. The system enables online access for real-time recordings, which are used both for demonstration purposes, in individual [student] exercises and in scientific investigations. Long-term registration of wind turbine loads results in a unique database of noncommercial time series, which are available for practicing fatigue calculations and extreme loads estimation in basic wind turbine courses. Power quality analysis is carried out based on high speed sampled, three-phase voltage and current signals. The wide spectrum of sensors enables a detailed study of the correlation between meteorological, mechanical and electrical quantities. Measurements are acquired by a PC placed at the wind turbine site near Risø National Laboratory. The PC can be remotely controlled from DTU, which gives the students the opportunity to work on an operating wind turbine. Furthermore, measurements are published on WindData.com, which facilitates cooperation with other Universities.

Schmidt Paulsen, U.

2006-01-01

90

Comparison study of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

A study was conducted to investigate the performance of a proposed delta-blade wind turbine compared to other existing wind-powered generators. The application for each of the machines was to provide energy supply to an irrigation water pumping scenario in Alberta. Wind generation scenarios were constructed for each of the manufacturers' standard units based on first principles of wind energy conversion. The performance analysis and subsequent economic evaluation depend significantly on the graphical interpretation of wind generator load factors derived in a prior study performed for the Government of British Columbia. The technical analysis focused primarily on a delta-blade machine, whose the key advantage is simplicity. Current aerogenerator systems tend to rely on complex electronic controllers and measuring devices. The delta-blade reacts mechanically to changing conditions and as the system employs low rotational rotor speed, there should be less opportunity for component failure. Some conclusions are: provided it achieves the expected high energy conversion efficiency, the delta-blade and variable capacity pump system concept is an economical alternative, electric grid supply is more economical at this time than wind conversion systems assuming a common economic comparison, the energy conversion and transfer concepts for the delta-blade system appear technically sound, although the stroke control box and internal mechanisms require careful development and testing, and application of the delta-blade system to a year-round duty cycle would be highly cost advantageous for continued development of the concept. 11 refs., 8 tabs.

1982-04-01

91

Airfoil data for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Some of the problems encountered by wind turbine designers in applying aerodynamic characteristics of airfoil sections to design of wind energy conversion systems are reviewed. It is necessary to know airfoil characteristics over a wider range of Reynolds numbers and angles of attack than is necessary for aircraft applications. Some of the studies of the effects of changing airfoils on wind turbine performance are also reviewed.

Snyder, M.H.

1981-01-01

92

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

93

Megawatt wind turbines gaining momentum  

International Nuclear Information System (INIS)

Through the short history of the modern wind turbine, electric utilities have made it amply clear that they have held a preference for large scale wind turbines over smaller ones, which is why wind turbine builders through the years have made numerous attempts develop such machines - machines that would meet the technical, aesthetic and economic demands that a customer would require. Considerable effort was put into developing such wind turbines in the early 1980s. There was the U.S. Department of Energy's MOD 1-5 program, which ranged up to 3.2 MW, Denmark's Nibe A and B, 630 kW turbine and the 2 MW Tjaereborg machine, Sweden's Naesudden, 3 MW, and Germany's Growian, 3 MW. Most of these were dismal failures, though some did show the potential of MW technology. (au)

1996-01-01

94

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

95

Potential health impact of wind turbines  

International Nuclear Information System (INIS)

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

96

Grid connections of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

While many countries in Europe and worldwide now produce electric power using wind turbines, this usually accounts for a very small proportion of power demand nationally. The trend for wind turbines to be connected to weak electrical networks is assessed here together with a discussion of the factors limiting the success of such projects. Harmonic filters for wind farms may need to be fitted to overcome distortion on rural networks especially for evening use. Network voltages will be altered with the inclusion of wind generated power and these difficulties will need to be overcome to avoid turbine shut-downs. The turbines themselves can suffer from generator overheating where imbalances occur on rural networks. Flicker, produced by voltage fluctuations, causes annoyance to electricity customers. Each difficulty must be overcome if wind generated power is to become commonplace. (UK)

Gardner, P. [Garrad, Hassan and Partners, Bristol (United Kingdom)

1995-03-01

97

Vertical axis wind turbines  

Energy Technology Data Exchange (ETDEWEB)

A vertical wind turbine having vertical blades, each blade being connected intermediate its ends by a hinge to a support arm having a hub that enables the blades to rotate around a vertical axis, a tie wire connected to the blade at positions spaced along the blade from the hinge, said tie wire engaging a spring-loaded pulley disposed inwardly of the blades, the arrangement being such that when the angle of inclination of the blades to the vertical axis alters under the action of centrifugal force the tie wire exerts a force on the pulley opposing the spring force whereby as the turbine speeds up the blades will remain at a predetermined angle of inclination until the force exerted by the wire exceeds the force of the spring. One end of the tie wire can be connected to a position on one blade and connected to another position on another blade so that all of the blades adopt the same angle of inclination to the vertical axis.

Delgado, P.E.; Holmes, B.A.

1981-06-23

98

Wind turbines in Latin America  

Energy Technology Data Exchange (ETDEWEB)

An overview of the development of wind turbines, water pumping and electric generation, in Latin America is given. There are a number of regions with average windspeeds above 5 m/s, however the greatest wind energy potential is in Southern Argentina. The market potential is large, but substantial barriers impede the use of wind energy for generating electricity.

Nelson, V.; Caldera, M.E.

1987-06-01

99

Wind turbines and environment management  

Energy Technology Data Exchange (ETDEWEB)

The environment protection and management aspects of small and large scale wind turbines are examined. Legal aspects on municipal level are discussed. The relation with regional and national management is illustrated by investigations for a planned wind energy park. It is argued that because of environment effects and long term management procedures, the establishment of wind energy generators causes many problems.

Vaneck, P.; Koekebakker, P.

1983-05-01

100

Wind turbines in Latin America  

Energy Technology Data Exchange (ETDEWEB)

An overview of the development of wind turbines, water pumping and electric generation, in Latin America is given. There are a number of regions with average windspeeds above 5 m/s, however the greatest wind energy potential is in Southern Argentina. The market potential is large, but substantial barriers impede the use of wind energy for generating electricity.

Nelson, V.; Caldera, E.M.

1986-01-01

 
 
 
 
101

Wind turbine supply in Canada  

International Nuclear Information System (INIS)

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

102

Methodology for wind turbine blade geometry optimization  

Energy Technology Data Exchange (ETDEWEB)

Nowadays, the upwind three bladed horizontal axis wind turbine is the leading player on the market. It has been found to be the best industrial compromise in the range of different turbine constructions. The current wind industry innovation is conducted in the development of individual turbine components. The blade constitutes 20-25% of the overall turbine budget. Its optimal operation in particular local economic and wind conditions is worth investigating. The blade geometry, namely the chord, twist and airfoil type distributions along the span, responds to the output measures of the blade performance. Therefore, the optimal wind blade geometry can improve the overall turbine performance. The objectives of the dissertation are focused on the development of a methodology and specific tool for the investigation of possible existing wind blade geometry adjustments. The novelty of the methodology presented in the thesis is the multiobjective perspective on wind blade geometry optimization, particularly taking simultaneously into account the local wind conditions and the issue of aerodynamic noise emissions. The presented optimization objective approach has not been investigated previously for the implementation in wind blade design. The possibilities to use different theories for the analysis and search procedures are investigated and sufficient arguments derived for the usage of proposed theories. The tool is used for the test optimization of a particular wind turbine blade. The sensitivity analysis shows the dependence of the outputs on the provided inputs, as well as its relative and absolute divergences and instabilities. The pros and cons of the proposed technique are seen from the practical implementation, which is documented in the results, analysis and conclusion sections. (orig.)

Perfiliev, D.

2013-11-01

103

Control of an offshore wind turbine modeled as discrete system  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Offshore wind turbines are installed at the sea and present a series of advantages such as wind tends to blow stronger and consistently with less turbulence. This work studies the dynamic behavior of wind turbines modeled as an inverted pendulum. Besides, as this type of pendulum is originally unstable, it is proposed a proportional control to stabilize its behavior.

Guimara?es, Pedro; A?vila, Suzana

2013-01-01

104

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

2010-05-25

105

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.

Henrik S. Toft

2010-02-01

106

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

2014-01-01

107

Probabilistic design of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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. (author)

Sorensen, J. D. [Aalborg University and Riso-DTU, Sohngaardsholmsvej 57, Aalborg (Denmark); Toft, H. S. [Aalborg University, Sohngaardsholmsvej 57, Aalborg (Denmark)

2010-07-01

108

Capacity factor of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The power generated by a wind turbine depends on both the design characteristics of the turbine and the properties of the wind resource. These parameters determine the capacity factor (ratio of average power output to rated power of the turbine). Since detailed information on the wind-speed frequency is often lacking, the shape factor (k) of the Weibull distribution is taken to be equal to 2, which may lead to significant errors. It is our aim to estimate capacity factors for shape factors between 1.5 and 3 and for sites with average wind speeds ranging from 4 to 8 m/s. The results have been analyzed to obtain a general form for the capacity factor. Our method may be useful to turbine manufacturers in designing electronic control systems. (Author)

Abed, K.A.; El-Mallah, A.A. [National Research Centre, Dokki, Giza (Egypt). Mechanical Engineering Dept.

1997-05-01

109

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

110

Lightning protection of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Wind turbines are, due to their design and often their locations, prone to a relatively high incidence of lightning strikes, the earthed tower providing an extremely attractive lightning path. The damage done by a lightning strike can result in a large amount of turbine down-time and resulting loss in revenue. A Framework 4 Joule project has recently started to investigate the risk that lightning poses to wind turbines and what can be done to minimise the damage in the event of a lightning strike. This paper gives details of the project, explaining the various areas in which work will be undertaken, including earthing, personnel safety, blade protection and bearing protection. Preliminary findings of a data collection exercise are presented. The data, provided by ISET in Germany and WindStats in Denmark, has been analysed at UMIST. The results serve to further underline the need for lightning protection and also give a guide to which components of a turbine are most vulnerable to lightning damage. Initial results detailing the level of risk posed by lightning to a wind turbine are also presented. These calculations examine the worst case increase in the number of lightning strikes to a wind turbine when lightning protection is added to a set of blades on a turbine with full span pitch control. (Author)

Cotton, I.; Jenkins, N. [Manchester Univ. (United Kingdom). Inst. of Science and Technology; Haigh, S. [AEA Technology, Culham (United Kingdom); Hatziargyriou, N. [National Technical Univ. of Athens (Greece); Hancock, M.; Carter, J. [Taywood Aerolaminates (United Kingdom); Jaquemotte, P. [Tacke WindTechnik GmbH (United Kingdom)

1997-06-01

111

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

112

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

113

Foundations for offshore wind turbines.  

Science.gov (United States)

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

Byrne, B W; Houlsby, G T

2003-12-15

114

Control system on a wind turbine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim for this project is to prepare a wind turbine controller and a wind turbine computer model suitable for controller development. The wind turbine is a Vestas V27, and the wind turbine drive train is modified by ChapDrive with a specified hydraulic transmission. Both the pitch and the rotor speed can be regulated for the modified wind turbine. The model is primarily based on a set of given wind turbine rotor characteristics, transmission specifications and transmission test data. The co...

Varpe, Steffen Andreas

2008-01-01

115

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

116

Fault Behavior of Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Synchronous generators have always been the dominant generation type in the grid. This fact affected both planning and operation of power systems. With the fast increase of wind power share in the grid in the last decade, the situation is changing. In some countries wind power represents already a consistent amount of the total generation. Wind turbines can be classified as non-synchronous generation and they behave differently than synchronous generation under many circumstances. Fault behav...

2012-01-01

117

Multilevel converters for 10 MW Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 cand...

Ma, Ke; Blaabjerg, Frede

2011-01-01

118

Active control: Wind turbine model  

Energy Technology Data Exchange (ETDEWEB)

This report is a part of the reporting of the work done in the project `Active Control of Wind Turbines`. This project aim is to develop a simulation model for design of control systems for turbines with pitch control and to use that model to design controllers. This report describes the model developed for controller design and analysis. Emphasis has been put on establishment of simple models describing the dynamic behavior of the wind turbine in adequate details for controller design. This has been done with extensive use of measurements as the basis for selection of model complexity and model validation as well as parameter estimation. The model includes a simple model of the structure of the turbine including tower and flapwise blade bending, a detailed model of the gear box and induction generator, a linearized aerodynamic model including modelling of induction lag and actuator and sensor models. The models are all formulated as linear differential equations. The models are validated through comparisons with measurements performed on a Vestas WD 34 400 kW wind turbine. It is shown from a control point of view simple linear models can be used to describe the dynamic behavior of a pitch controlled wind turbine. The model and the measurements corresponds well in the relevant frequency range. The developed model is therefore applicable for controller design. (au) EFP-91. 18 ills., 22 refs.

Bindner, Henrik

1999-07-01

119

Wind turbines and human health.  

Science.gov (United States)

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

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

2014-01-01

120

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

 
 
 
 
121

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

122

Vertical axis wind turbine airfoil  

Energy Technology Data Exchange (ETDEWEB)

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

123

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

124

Predicting Faults in Wind Turbines Using SCADA Data  

DEFF Research Database (Denmark)

The cost of operation and maintenance of wind turbines is a significant part of the overall cost of wind turbines. To reduce this cost a method for enabling early fault detection is proposed and tested in this paper. The method is taking advantage of the fact that wind turbines in wind farms are located near similar wind turbines. This is done by generating a model for each turbine, the model is then used to evaluate the performance of that turbine and the nearby turbines. The evaluations from the models are then combined and used as votes to identify the faulty turbines. The method is applied and tested on historical Supervisory Control And Data Acquisition (SCADA) data from nine operational turbines over a testing period of nine months. The performance of the fault detection is found to be acceptable based on the testing period. During the testing period several gear related services were performed, some of these were predicted by the proposed fault detection systems. The advantage of the purposed method isthat it applicable for operational turbines without requiring any extra measurements, since the used SCADA data is available from most modern wind turbines.

Borchersen, Anders Bech; Larsen, Jesper Abildgaard

2013-01-01

125

Wind Turbine in Yawed Operation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The task of this project was to investigate the near wake, performance characteristics and yaw moment on a model wind turbine. The test turbine is a horizontal axis three bladed machine with a rotor diameter of 0.9 meter. Initially it is an upwind turbine, but was used for downwind measurements as well by rotating the blades and the entire construction 180^0. For the wake measurements the tip speed ratio was set to be TSR=3, TSR=6 and TSR=9 to describe the different regimes; partly stalled, o...

Loland, Kari Medby

2011-01-01

126

Design of Wind Turbine Vibration Monitoring System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In order to ensure safety of wind turbine operation and to reduce the occurrence of faults as well as to improve the reliability of wind turbine operation, a vibration monitoring for wind turbine is developed. In this paper, it analyses the enlargement of all the parts of the structure and the working mechanism, the research method of wind turbine operation vibration is introduced, with the focus being the use of the sensor principle. Finally the hardware design and sof...

Shoubin Wang; Wei Gong; Gang Su; Hongyue Sun

2013-01-01

127

The influence of wind turbines on telecommunications  

Energy Technology Data Exchange (ETDEWEB)

Next to noise pollution, disturbance of telecommunications is a disadvantage of using wind turbines. A deliberate selection of the location of wind turbines is necessary to guarantee the quality of the connections. This article indicates the telecommunication services which have interest in the site selection of wind turbines, because of possible conflicts. Next it will be discussed how to prevent these conflicts by taking it into account while selecting a location for wind turbines. 3 figs., 6 refs., 3 tabs.

Berkhuizen, J.C.; Van Kats, P.J.

1988-05-01

128

Experiences with certification of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

This paper gives a presentation of the experience gained by DNV and Risoe in connection with Type Approval and Certification of Wind Turbines. The paper describes the progress concerning the development of the regulations for wind turbines, the view on the approval system seen from the various interested partners side, the methods used in connection with verification of the wind turbines and various approval systems in other countries. It is concluded that there is still a need for certification of wind turbines. (author)

Skamris, C. [Risoe National Lab., Roskilde (Denmark); Eriksson, C. [DNV, Copenhagen (Denmark)

1996-12-31

129

Power Control Design for Variable-Speed Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 demonstra...

Vidal, Yolanda; Acho, Leonardo; Luo, Ningsu; Zapateiro La Hoz, Mauricio Fabia?n; Pozo, Francesc

2010-01-01

130

Power Control Design for Variable-Speed Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

2012-01-01

131

The noise generated by wind turbines  

International Nuclear Information System (INIS)

Sound propagation damps down with distance and varies according to different parameters like wind direction and temperature. This article begins by recalling the basic physics of sound wave propagation and gives a list of common noises and corresponding decibels. The habitual noise of wind turbines 500 m away is 35 decibels which ranks it between a quiet bedroom (30 decibels) and a calm office (40 decibels). The question about whether wind turbines are a noise nuisance is all the more difficult as the feeling of a nuisance is so objective and personal. Any project of wind turbines requires a thorough study of its estimated acoustic impact. This study is a 3 step approach: first the initial noise environment is measured, secondly the propagation of the sound generated by the wind turbine farm is modelled and adequate mitigation measures are proposed to comply the law. The law stipulates that the increase of noise must be less than 5 db during daylight and less than 3 db during night. (A.C.)

2012-06-01

132

Wind turbines. Product guide  

Energy Technology Data Exchange (ETDEWEB)

Product guide presented gives names and addresses of Canadian, USA, EEC, Swiss, Scandinavian and Japanese vertical and horizontal turbine manufacturers, with names of rotor, blade, tower and gear manufacturers included. Technical specifications for each item of equipment are tabulated.

1986-08-01

133

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

134

Icing losses on wind turbines  

Energy Technology Data Exchange (ETDEWEB)

This PowerPoint presentation discussed some of the energy losses that can occur as a result of icing on wind turbines. Airfoil deterioration can occur in the presence of rime and glaze ice. Anemometers are also impacted by ice, and shut-downs can occur as a result of icing events. Availability deficits that occur during the winter months can lead to annual energy losses of 0.5 percent. The impact of icing events on total wind power energy production in Quebec is estimated at between 1.3 percent to 2.7 percent. Ice loss estimates are considered during the pre-construction phases of wind power projects. However, ice loss prediction methods are often inaccurate. Studies have demonstrated that preconstruction masts show a reasonable correlation with wind turbine icing, and that icing losses are site-specific. tabs., figs.

Duncan, T.; Fotsing, I.; Pearson, S. [Garrad Hassan Canada Inc., Ottawa, ON (Canada)

2010-07-01

135

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

136

Analysis of the Environmental Impact on Remanufacturing Wind Turbines  

Science.gov (United States)

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

Sosa Skrainka, Manuel R.

137

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

138

Wind turbines in urban environments  

Energy Technology Data Exchange (ETDEWEB)

The installation of so-called 'urban wind turbines' in cities and on infrastructural objects such as highway noise barrieres is attracting growing interest from inventors, equipment manufacturers, architects and project developers. And while the knowledge base is still small and practical experience limited in this technically challenging wind environment, a number of companies are racing ahead with their new concepts. (au)

Vries, E. de

2001-07-01

139

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

140

Dynamic modeling and simulation of wind turbines  

International Nuclear Information System (INIS)

Using wind energy for generating electricity in wind turbines is a good way for using renewable energies. It can also help to protect the environment. The main objective of this paper is dynamic modeling by energy method and simulation of a wind turbine aided by computer. In this paper, the equations of motion are extracted for simulating the system of wind turbine and then the behavior of the system become obvious by solving the equations. The turbine is considered with three blade rotor in wind direction, induced generator that is connected to the network and constant revolution for simulation of wind turbine. Every part of the wind turbine should be simulated for simulation of wind turbine. The main parts are blades, gearbox, shafts and generator

2002-04-01

 
 
 
 
141

Floating wind turbines :the transport phase  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The worldwide demand of renewable energy is increasing rapidly because of the climate problem. Wind energy appears as a clean and good solution to cope with a great part of this energy demand. Therefore, floating wind turbines have been investigated as a possible solution to increase the efficiency from the wind, as a renewable energy source. A critical phase for the floating wind turbines is the transport phase. Economically, the floating wind turbines should be transported in an upraised po...

Solli, Knut Jostein

2008-01-01

142

Transportation Excellence for Wind Turbine Nacelle  

Digital Repository Infrastructure Vision for European Research (DRIVER)

With the growing demand of renewable wind energy, logistics and operations associated with a wind turbine makes for compelling study and analysis. The study entails understanding of transporting a wind turbine nacelle from Denmark till Australia. The methods of transporting the wind turbine nacelle and the modes of transportation that are currently in use have been studied. Factors that are detrimental to efficient shipping have been reviewed with existing literature and analysed for a wind t...

Babu Thennarasu, Ganesh; Kumar Annamalai Muralidharan, Hemanth

2012-01-01

143

Grid integration of Danish wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The rapid growth of wind turbines being connected to the Danish electricity supply system has provided insight into many problems of linking wind turbines to electric utility systems. The Danish electricity supply system, accounting rules for wind power generation, grid-connection to wind turbines, a power integration study and a wind-diesel project are described with special emphasis on how to handle surplus power. (CLS).

Nielsen, P. (DEFU, Lyngby (DK))

1991-01-01

144

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

145

Risk of collision between service vessels and offshore wind turbines  

International Nuclear Information System (INIS)

Offshore wind farms are growing in size and are situated farther and farther away from shore. The demand for service visits to transfer personnel and equipment to the wind turbines is increasing, and safe operation of the vessels is essential. Currently, collisions between service vessels and offshore wind turbines are paid little attention to in the offshore wind energy industry. This paper proposes a risk assessment framework for such collisions and investigates the magnitude of the collision risk and important risk-influencing factors. The paper concludes that collisions between turbines and service vessels even at low speed may cause structural damage to the turbines. There is a need for improved consideration of this kind of collision risk when designing offshore wind turbines and wind farms.

2013-01-01

146

Small-Scale Vertical Axis Wind Turbine Design  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The thesis focuses on the design of a small vertical axis wind turbine rotor with solid wood as a construction material. The aerodynamic analysis is performed implementing a momentum based model on a mathematical computer program. A three bladed wind turbine is proposed as candidate for further prototype testing after evaluating the effect of several parameters in turbine efficiency, torque and acceleration. The results obtained indicate that wood is a suitable material for rotor cons...

Castillo Tudela, Javier

2011-01-01

147

Preview Control for Wind Turbines  

Science.gov (United States)

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

Ozdemir, Ahmet Arda

148

Aerodynamics of wind turbines. Proceedings  

Energy Technology Data Exchange (ETDEWEB)

The papers in this volume covered the following topics: measurement of aerofoil characteristics, high lift aerofoils, CFD theory and methods, dynamic stall, yawed rotor phenomena, measurement and modelling of turbulent inflow and its effects, structural load calculations, wind turbine blade icing and rotor noise prediction. (author)

Ward, J.M. (ed.)

1994-08-01

149

Health monitoring for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Condition monitoring is an important component in the predictive maintenance of wind turbines and can allow for the maintenance of equipment before a failure occurs. This poster presentation described the method used by the consulting firm Garrad Hassan to predict potential component failure and to target wind turbines that need predictive maintenance or further inspection. Component temperatures were recorded by the SCADA systems of 400 wind turbines of 5 different types and then analyzed in relation to their generator bearings; slip ring; winding; cooling air; gearbox bearing and oil temperature; main shaft bearings temperature; and hydraulic oil temperatures. Component temperatures were then normalized by calculating the per-turbine linear or log-linear fit to the previous power production record and the nacelle or ambient temperature. The fitted expected temperature was then subtracted from the observed component temperature so that signals with high variability were reduced to flat signals. The normalized signals were then median filtered by day, and the resulting trends were analyzed in order to determine signals that deviated more than 5 degrees C above normal. The correspondence between the deviations and known component failure or downtime was then evaluated. Results of the study showed that some signals can be reasonable or excellent early indicators of component failure. tabs., figs.

Duncan, T. [Garrad Hassan Canada Inc., Ottawa, ON (Canada)

2010-07-01

150

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

151

Lubrication systems for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

All wind turbines use several bearings and drives that require consistent and effective lubrication, regardless of the design of the turbine. Correct lubrication extends the time between service intervals, and also protects and extends the life of equipment. It also ensures that the proper amount of lubricant is applied at the right time. This paper discussed lubrication systems for wind turbines. It addressed specific topics such as application oriented lubrication systems; bearing dosage systems; and gear lube applicators. The advantages of automatic lubrication include lower costs for repairs, square parts and lubricant; improved operating times, and less costly downtime; longer maintenance intervals; longer bearing life resulting from regular, metered lubrication amounts; contribution to safety and the environment; and improved corrosion protection, especially in salty climates. figs.

NONE

2010-07-01

152

Design of Wind Turbine Vibration Monitoring System  

Directory of Open Access Journals (Sweden)

Full Text Available In order to ensure safety of wind turbine operation and to reduce the occurrence of faults as well as to improve the reliability of wind turbine operation, a vibration monitoring for wind turbine is developed. In this paper, it analyses the enlargement of all the parts of the structure and the working mechanism, the research method of wind turbine operation vibration is introduced, with the focus being the use of the sensor principle. Finally the hardware design and software of this system is introduced and the main function of this system is described, which realizes condition monitoring of the work state of wind turbines.

Shoubin Wang

2013-04-01

153

Sound wave contours around wind turbine arrays  

International Nuclear Information System (INIS)

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

154

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

155

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

156

Large, horizontal-axis wind turbines  

Science.gov (United States)

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

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

1984-01-01

157

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

158

Contribution of variable-speed wind turbines to voltage control  

Energy Technology Data Exchange (ETDEWEB)

Variable speed, grid connected, wind turbines open new possibilities for voltage control, because they use electronic converters, which may regulate the reactive power interchange with the grid. This paper proposes two voltage control schemes for variable speed wind turbines with double-fed induction generator. The first scheme acts on the wind-turbine power factor, while the latter acts directly on the converter current. Advantages and draw backs of both techniques are discussed. Both control techniques have been tested by simulations of a base case, which represent a synchronous generator, a wind farm and a local load, and several disturbances such as the loss of compensator capacitors. (author)

Ledesma, P.; Usaola, J.

2003-07-01

159

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

160

Fluid-Structure Interaction Analysis of Wind Turbines  

Science.gov (United States)

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

Hsu, Ming-Chen

 
 
 
 
161

Floating wind turbines at medium water depths  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Offshore wind turbines have an enormous potential in terms of larger average wind speeds and low surface roughness compared to their onshore counterpart. Shallow water fixed wind turbines are ranked as a mature technology but are also limited by the price tag of creating and installing fixed installations for increasing depths. Hywind, which is a floating wind turbine concept developed by Statoil with focus on larger depths but may prove beneficial for shallower depths and fill the present vo...

Furunes, Eirik Wie

2010-01-01

162

The stiffness tailoring of megawatt wind turbine  

Science.gov (United States)

Wind power has developed rapidly in recently years, the wind turbine's blades determine the performance of the device and the power. In this paper, we used integrated tailoring aimed at institutional characteristics of horizontal axis wind turbine with the composite laminated plate theory, then analyzed the composite blades of wind turbine by combining experimental analysis and finite elements method, and finally studied the influences that composite material properties on stiffness tailoring with changes in the number of different layers.

Li, Z. M.; Li, C.; Ye, Z.; Wu, P.; Lu, Y. F.

2013-12-01

163

Dynamic models for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Attention is paid to the contribution of the author's institute to the DYNAMO research. The DYNAMO project is a continuation of a previous European Community funded research on Integrated Dynamic Models of Flexible Wind Turbines (INDYMO). The ultimate goal is to reduce the costs of energy generated by Wind Energy Conversion Systems (WECS). This goal can be achieved when each individual WECS has low construction costs, long lifetime and a maximum amount of produced energy. In order to design such an optimized system a Design Tool is needed, capable to simulate and analyze the dynamic behavior of a complete WECS. The Delft University developed WECS (DUWECS) is extended in order to analyze the dynamic impacts of the different components on the complete WECS behavior. Dynamical models of the different wind turbine components are described. The structural dynamics of the wind turbine will be emphasized. The theoretical models are implemented in DUWECS in order to predict the dynamic response of a complete WECS. Reliable predictions can only be made when the used models are accurate descriptions of the reality. To this end validation of the dynamic models is pursued. Finally advanced control strategy is developed and demonstrated. It is shown that by application of advanced controllers fatigue loads in both rotor shafts and blades can be reduced significantly. Experimental results are supporting the theoretical achievements. 52 figs., 1 tab., 2 appendices, 138 refs.

Bongers, P.; Van Baars, G.; Dijkstra, S.; Bosgra, O.

1993-01-01

164

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

165

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

166

New wind turbines of high profitability  

International Nuclear Information System (INIS)

To generate more quantities of electric energy from wind it is necessary to use the new type of wind turbine built in regulable mantle's nozzle, which the free air stream of wind replaces in programmed i.e. regulated and partially concentrated. In this way their efficiency is multiplied. New turbines are getting more power (P = f(v"3)) from cube of higher speeds from weaker and medium winds. Short economic analysis evidently indicates that profit achieved by new wind turbines is 5 (five) times higher than that by conventional turbines. (author)

1999-12-10

167

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

168

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

169

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

170

Cooperative investment in wind turbines  

International Nuclear Information System (INIS)

Two fiscal options to invest in wind turbines are available in the Netherlands for enterprises: the EIA (energy investment deduction) and the VAMIL (random debit of environmental investments). Non-profit organizations (in this case, e.g. private persons, foundations, associations) can make use of the subsidy EINP (energy supply in non-profit and other special sectors). Attention is paid to the use of the fore-mentioned legal forms, while there are other, more advantageous forms, that can be used to start a cooperative to set up a wind farm

2002-02-01

171

Motion of floating wind turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Motion of floating wind turbines has been studied. A literature study on different concepts and what tools are available for simulating them is presented. Marintek’s simulation software SIMO is used for time simulations. In the calculations, the hydrodynamic forces, mooring line forces and aerodynamic forces from the tower and rotor are taken into account. In addition a pitch control algorithm is used for the rotor blades. Results are compared to available experimental results from mo...

Linde, Břrge

2010-01-01

172

Performance comparison of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Commonly accepted power curves of wind turbines are essential for an effective comparison and for a reliable energy output prediction. This presumes a detailed knowledge of the possible error and uncertainty sources which can affect power curve measurements. The study concentrates mostly on physical effects which cannot be evaluated on a standardized way and therefore have to be treated with care. It does not claim for completeness but it points out some sources of errors which appear to be important. (author).

Nebel, M.; Molly, J.P. (WISA Energiesysteme GmbH (DE))

1992-01-01

173

Report on the safety of wind turbines installations; Rapport sur la securite des installations eoliennes  

Energy Technology Data Exchange (ETDEWEB)

This report aims to study the regulatory framework governing the safety of wind turbines and proposes improvement actions. It concerns the wind turbines risk assessment, the technical bases of the wind turbines safety, the regulation relative to the safety and possible evolutions. (A.L.B.)

Guillet, R.; Leteurtrois, J.P.

2004-07-01

174

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

International Nuclear Information System (INIS)

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

175

Performance of propeller wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Presented herein is a parametric study of the performance of propeller wind turbines with realistic drag/lift ratios. Calculations were made using the complete Glauert vortex blade element theory in annular streamtube elements with the complete turbine performance being the sum of the elemental results up to a specified tip speed ratio. The objective here is to exhibit a new computational technique which yields performance directly when tangential speed ratio and section aerodynamic characteristics are specified. It was found that for a tip speed ratio of 4, turbines with drag/lift ratios of 0.00 and 0.01 had power coefficients of 0.575 and 0.55, respectively. The off-design performance of the finite drag/lift was far better than that of their zero drag counterparts, except in a + or - 20% region about the design conditions. Tolerance to off-design operation increased with decreasing tip speed ratios so that the annual energy capture for tip speed ratios between 2 and 4 was about 87% of the ideal turbine value. The results are intended to provide a basis for re-evaluation of the power range classes of fixed pitch turbines and design tip speed ratios.

Wortman, A.

1983-11-01

176

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; one is based on high temperature superconductors; 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 4 K and 50 K, 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 Cost of Energy 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. © 2013 AIP Publishing LLC.

Jensen, Bogi Bech; Mijatovic, Nenad

2013-01-01

177

Control systems for controlling a wind turbine  

Energy Technology Data Exchange (ETDEWEB)

A distributed module control system is described for controlling a wind turbine using multiple controls and monitors comprising multiple modules that include microcontrollers, and having data input terminals and data output terminals; high level logic circuitry interconnecting the modules via selected data input and data output terminals; and certain modules also connected with the turbine monitors and controls to control operation of the wind turbines in response to monitoring of turbine operation. 7 figs.

Cousineau, K.L.

1994-01-11

178

Wind Turbine Modelling, Control and Fault Detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Wind turbines are subject to dynamic loading due to both stochastic wind speed variation caused by turbulence and periodic wind speed variation caused by wind shear and the tower shadow effect. Therefore, a detailed non-linear wind turbine model capable of simulating these effects is developed and described in detail. A linearised periodic state space description of a simplified version of the non-linear model is obtained as a function of the rotor azimuth angle. From this, ...

Dolan, Barry

2010-01-01

179

Adaptive Fuzzy Logic Control of Wind Turbine Emulator  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a Wind Turbine Emulator (WTE based on a separately excited direct current (DC motor is studied. The wind turbine was emulated by controlling the torque of the DC motor. The WTE is used as a prime mover for Permanent Magnet Synchronous Machine (PMSM. In order to extract maximum power from the wind, PI and Fuzzy controllers were tested. Simulation results are given to show performance of proposed fuzzy control system in maximum power points tracking in a wind energy conversion system under various wind conditions. The strategy control was implemented in simulation using MATLAB/Simulink.

BOUZID Mohamed Amine

2014-03-01

180

Climate change drives wind turbines  

International Nuclear Information System (INIS)

The development and prospects for wind power resources, technologies, investment, financing and banking, incentive policies, and operation and maintenance have become popular issues in wind power industry. An exhibition in May 2007 in Milan, Italy (EWEC 2007), with 229 stands on wind power technologies and techniques coinciding with the Conference, confirmed the popularity of these issues. Governments, International organisations, NGOs, universities, research institutions, and private sector are all paying attention to these issues. Developing countries, China and India in particular, are playing an increasingly important role in developing wind power. The EWEC 2007 confirmed that wind energy will make a substantial contribution to achieving the European Council's recently adopted target: 20% of EU energy consumption coming from renewables by 2020. The Chinese government also announced its new wind power development target: additional installation of new capacity of 5 GW in 2010 and 30 GW in 2020. It is evident that more and more wind turbines in both developed and developing countries will be driven by climate change

2007-12-01

 
 
 
 
181

Climate change drives wind turbines  

International Nuclear Information System (INIS)

The development and prospects for wind power resources, technologies, investment, financing and banking, incentive policies, and operation and maintenance have become popular issues in wind power industry. An exhibition in May 2007 in Milan, Italy (EWEC 2007), with 229 stands on wind power technologies and techniques coinciding with the Conference, confirmed the popularity of these issues. Governments, International organisations, NGOs, universities, research institutions, and private sector are all paying attention to these issues. Developing countries, China and India in particular, are playing an increasingly important role in developing wind power. The EWEC 2007 confirmed that wind energy will make a substantial contribution to achieving the European Council's recently adopted target: 20% of EU energy consumption coming from renewables by 2020. The Chinese government also announced its new wind power development target: additional installation of new capacity of 5 GW in 2010 and 30 GW in 2020. It is evident that more and more wind turbines in both developed and developing countries will be driven by climate change. (author)

2007-12-01

182

Hybrid Optimization for Wind Turbine Thick Airfoils  

Energy Technology Data Exchange (ETDEWEB)

One important element in aerodynamic design of wind turbines is the use of specially tailored airfoils to increase the ratio of energy capture and reduce cost of energy. This work is focused on the design of thick airfoils for wind turbines by using numerical optimization. A hybrid scheme is proposed in which genetic and gradient based algorithms are combined together to improve the accuracy and the reliability of the design. Firstly, the requirements and the constraints for this class of airfoils are described; then, the hybrid approach is presented. The final part of this work is dedicated to illustrate a numerical example regarding the design of a new thick airfoil. The results are discussed and compared to existing airfoils.

Grasso, F. [ECN Wind Energy, Petten (Netherlands)

2012-06-15

183

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

184

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

185

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 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 det...

2009-01-01

186

Electromagnetic Interference on Large Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 d...

Florian Krug; Bastian Lewke

2009-01-01

187

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 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...

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

2013-01-01

188

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 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 solve...

Yu-qiao Zheng; Zhao, Rong-zhen; Hong liu

2013-01-01

189

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

190

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

1990-02-21

191

Aerolastic simulation of wind turbine dynamics  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The work in this thesis deals with the development of an aeroelastic simulation tool for horizontal axis wind turbine applications. Horizontal axis wind turbines can experience significant time varying aerodynamic loads, potentially causing adverse effects on structures, mechanical components, and power production. The needs for computational and experimental procedures for investigating aeroelastic stability and dynamic response have increased as wind turbines become lighter and more flexibl...

Ahlstro?m, Anders

2005-01-01

192

Wind turbines in simulated gusts  

Energy Technology Data Exchange (ETDEWEB)

The results of trials in the T4 wind tunnel to simulate the effects of gusts on wind turbines are reported. Three-bladed NACA 0012 and 0018 profile and a six bladed 0012 profile machines were examined in gusts of 10 sec duration. The mean free stream velocity was 7-8 m/sec and the gusts generated had an amplitude of 30-40 pct. An aeroelastic analysis was carried out from high speed photographic images taken at 400-4000 images/sec of the blades in steady and gusting flows. The power output was measured by using a variable resistance alternator in the wind turbine, and comparisons were made between the power extracted from a steady flow to flows marked by gusts. It was found that increasing the pitch angle of the blades lowered power coefficient, as predicted, and a maximum power coefficient of 0.42 was obtained, which was higher than predicted for the 0012 blades. An absence of significant vibration effects was noted, although permanent deformations did appear in the 0012 blades. Finally, gusting winds caused power fluctuations on the order of 74 pct, while the presence of gusts augmented the average power produced by up to 16 pct. 12 references.

Egozcue, C.; Leblanc, R.; Goethals, R.

1982-01-01

193

Grid support capabilities of wind turbines  

DEFF Research Database (Denmark)

Wind power has gained a significant penetration level in several power systems all over the world. Due to this reason modern wind turbines are requested to contribute to power system support. Power system operators have thus introduced grid codes, which specify a set of requirements for wind turbines, such as fault ride-through and reactive power supply during voltage sags. To date different wind turbine concepts exist on the market comprising different control features in order to provide ancillary services to the power system. In the first place the present chapter emphasizes the most important issues related to wind power grid integration. Then different wind turbine concepts are characterized and their grid support capabilities are analysed and compared. Simulation cases are presented in which the respective wind turbine concepts are subjected to a voltage dip specified in a grid code.

Michalke, Gabriele; Hansen, Anca Daniela

2013-01-01

194

Harmonization of wind turbines and DND radar  

Energy Technology Data Exchange (ETDEWEB)

This presentation summarized what Canada's Department of National Defence (DND) is doing to avoid conflict with the wind energy industry in terms of its air traffic control and air defence radars. DND conducted computerized simulations of proposed projects near the community of Forest in Lambton Shores, Ontario. The results did not indicate any conflict with current radar installations. However, proposals for further analysis should be submitted in the event of any major changes in the size of the turbines or location of the wind farms. It was concluded that DND fully supports the development of renewable energy resources but recommends early consultation with stakeholders to ensure a given installation does not cause unacceptable interference that could lead to costly changes or delays at a later stage in the wind farm development. figs.

Hawkes, J. [Department of National Defence, Ottawa, ON (Canada)

2008-07-01

195

Modeling Smart Structure of Wind Turbine Blade  

Science.gov (United States)

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

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

2012-06-01

196

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

197

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

198

Background sound levels and wind turbine noise  

International Nuclear Information System (INIS)

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

2005-05-23

199

Installation and initial operation of a 4100 watt wind turbine  

Science.gov (United States)

The results are presented of 211 days of operation of the 4.1 kilowatt wind turbine, which was the largest commercially available wind turbine. The wind turbine, electric controls and load bank, and the pivoted tower are described.

Tryon, H. B.; Richards, T.

1975-01-01

200

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

 
 
 
 
201

Noise annoyance from wind turbines a review  

International Nuclear Information System (INIS)

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

202

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] â?? [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

Shen, Wen Zhong

2009-01-01

203

Fuzzy Regulator Design for Wind Turbine Yaw Control  

Science.gov (United States)

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

Koulouras, Grigorios

2014-01-01

204

Fuzzy regulator design for wind turbine yaw control.  

Science.gov (United States)

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

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

2014-01-01

205

New wind turbine designs - Challenges and trends  

Energy Technology Data Exchange (ETDEWEB)

The paper presents some of the major development trends for wind turbines as well as for wind farms. This is done mainly on the basis of the Nordic market development. The main objectives when designing future wind energy systems are to continue the trends of reduction in cost of energy and improvement of reliability combined with improved power system integration features. The main trends for offshore wind turbines are presented, as they will constitute a very significant part of the market in the future. Also trends for onland wind turbines are presented as well as a discussion of what will limit the size of future wind turbines. Finally the very important wind power plant technology trends are presented again with emphasis on the requirements for the large offshore wind farms. (author)

Bindner, Henrik

2000-07-01

206

Noise measurements around the Nibe (Denmark) wind turbines and the Windane 31 wind turbine  

Science.gov (United States)

Noise around the two 640 kW wind turbines, and a 300 kW wind turbine at various distances and wind velocities was measured. The results are stated partly as the energy equivalent, A-weighted sound pressure level as a function of the wind velocity, partly as frequency analyses based on tape recordings of the A-weighted sound pressure level. A subjective evaluation of the noise emission from the wind turbines is given.

Kristensen, J.

207

Lightning protection of wind turbines  

Science.gov (United States)

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

Dodd, C. W.

1982-01-01

208

Reduction of Wind Turbine Torque Fluctuation Using Individual Pitch Control Based on Edgewise Moment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In order to eliminate the nonuniform force on the wind rotor caused by wind shear, tower shadow and turbulence and smooth the torque fluctuation of the wind turbine and the unbalanced loads on the wind turbine, a new individual pitch control strategy based on edgewise moment using single neuron PID controller is proposed. That is, the presented control strategy directly controls the blade edgewise moment generated by aerodynamic force. At the same time, to simulate the wind turbine loads, a d...

2013-01-01

209

How to squeeze more kilowatts from wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

Gipe, P.

1987-10-01

210

Actuator control of edgewise vibrations in wind turbine blades  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Edgewise vibrations with low aerodynamic damping are of particular concern in modern multi-megawatt wind turbines, as large amplitude cyclic oscillations may significantly shorten the life-time of wind turbine components, and even lead to structural damages or failures. In this paper, a new blade design with active controllers is proposed for controlling edgewise vibrations. The control is based on a pair of actuators/active tendons mounted inside each blade, allowing a variable control force...

2012-01-01

211

H-Darrieus Wind Turbine with Blade Pitch Control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A procedure for computing the optimal variation of the blades' pitch angle of an H-Darrieus wind turbine that maximizes its torque at given operational conditions is proposed and presented along with the results obtained on a 7?kW prototype. The CARDAAV code, based on the “Double-Multiple Streamtube” model developed by the first author, is used to determine the performances of the straight-bladed vertical axis wind turbine. This was coupled with a genetic algorithm opti...

Paraschivoiu, I.; Trifu, O.; Saeed, F.

2009-01-01

212

Lidars and wind turbine control. Pt. 1  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In recent years lidar technology found its way into wind energy. The main application is still the site assessment, but the possibility to optimize the energy production and reduce the loads by nacelle or spinner based lidar systems is becoming an important issue. In terms of control the inflowing wind field is the main disturbance to the wind turbine and most of the wind turbine control is designed to deal with variations in this disturbance. From control theory, the control performance can ...

Schlipf, David

2013-01-01

213

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

214

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

215

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

216

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.)

2011-02-01

217

Aeroacoustics of large wind turbines  

Science.gov (United States)

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

Hubbard, Harvey H.; Shepherd, Kevin P.

1991-01-01

218

Microprocessor control of a wind turbine generator  

Science.gov (United States)

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

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

1978-01-01

219

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

220

Wind turbines fundamentals, technologies, application, economics  

CERN Document Server

"Wind Turbines" addresses all those professionally involved in research, development, manufacture and operation of wind turbines. It provides a cross-disciplinary overview of modern wind turbine technology and an orientation in the associated technical, economic and environmental fields.  In its revised third edition, special emphasis has been given to the latest trends in wind turbine technology and design, such as gearless drive train concepts, as well as on new fields of application, in particular the offshore utilisation of wind energy. The author has gained experience over decades designing wind energy converters with a major industrial manufacturer and, more recently, in technical consulting and in the planning of large wind park installations, with special attention to economics.

Hau, Erich

2013-01-01

 
 
 
 
221

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

222

Vertical-axle wind turbine  

Energy Technology Data Exchange (ETDEWEB)

A vertical-axle wind turbine comprises tubal sliders on a vertical axle, horizontal members supported in tubular supports, blades, equipoises and a rope and reel system. Openings near both ends of the tubes accommodate stop-pins to control the turning range of the members up to 90 degrees whereby pairs of blades can oscillate when rotating, to secure maximum wind force. The tubal sliders are linked by chain links, and the top and the bottom sliders are connected to ropes under the control of the reel to facilitate elevating and descending of the bladed rotors. Two alternative counterpoise arrangements are disclosed as well as spring arrangements within the members for absorbing shock and regulating speed under centrifugal force. (author).

HsunFa Liu.

1990-05-23

223

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

224

Wind turbine control system modeling capabilities.  

Science.gov (United States)

At the National Renewable Energy Laboratory's (NREL's) National Wind Technology Center the authors are continuing to make progress in their ability to model complete wind turbine systems. An ADAMS(reg-sign) model of the NREL variable speed test bed turbin...

K. Pierce L. J. Fingersh

1998-01-01

225

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

226

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

2010-09-01

227

Performance assessment of a small wind turbine with crossflow runner by numerical simulations  

Energy Technology Data Exchange (ETDEWEB)

Most of the classical wind turbines are not able to start at wind speeds as low as 2-3 m/s. Other turbines, like Savonius, have a low maximum efficiency, which renders them useless in poor wind conditions. Therefore, new turbine designs are required to harvest wind power even when the wind speed is low. A wind turbine having a crossflow runner, similar to the Banki water turbine, is studied numerically in this work in order to estimate its performance. The results obtained suggest that this turbine has a considerable high starting torque and its maximum power coefficient is comparable to those of horizontal axis wind turbines. Based on the results obtained, some improvements of the design are proposed in order to further increase turbine performance. (author)

Dragomirescu, A. [University Politehnica of Bucharest, Department of Hydraulics, Hydraulic Machinery and Environmental Engineering, Splaiul Independentei 313, 060042 Bucharest (Romania)

2011-03-15

228

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

International Nuclear Information System (INIS)

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

229

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

230

An experimental investigation of wind turbine wakes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the present study the wake behind a scaled; Horizontal Axis Wind Turbine (HAWT) has been investigated. The experiments were performed at the Department of Energy and Process Engineering, at the Norwegian University of Science and Technology, NTNU. The turbine was installed in the wind tunnel at the department and measurements were performed at several distances behind the turbine to examine the development of the flow. A five-hole pitot probe was applied as measurement instrument. The inst...

2012-01-01

231

Grid integration of wind turbines. [Denmark  

Energy Technology Data Exchange (ETDEWEB)

In recent years, there has been a rapid growth in the number of wind turbines connected to the Danish electricity supply system. As of 1 January 1989, the total number of all grid-connected wind turbines in Denmark was 2050, with a total electrical capacity of 190 MW. In 1988, the power production was about 290 GWh, and this corresponded to about 1% of the country's electricity consumption. As of 1 January 1988, the total number of grid-connected small-scale wind turbines in Denmark was 1630, and the total electrical capacity was 110 MW. As a by-product of this technological advancement, a valuable collection of experiences has provided insight into many potential problems of linking wind turbines to electric utility systems. The Danish electricty supply system, accounting rules, guidelines for grid connection of wind turbines and two projects are briefly described. (AB).

Nielsen, P. (Research Association of Danish Electric Utilities (DK))

1990-01-01

232

Small power wind turbine (Type DARRIEUS  

Directory of Open Access Journals (Sweden)

Full Text Available This presentation focuses on the calculation for small vertical axis wind turbines (VAWT for an urban application. The fixed-pitch straight – bladed vertical axis wind turbine (SB-VAWT is one of the simplest types of wind turbine and accepts wind from any angle (no yaw system. This turbine is useful for moderate wind speeds (3 - 6 m/s. A case study is presented based upon the use of well documented symmetrical NACA 0012 turbine blade profile. We describe a solution for VAWT. To perform a linear static analysis in the structure, the commercial finite element analysis code ANSYS is used because of its flexibility for handling information in files written in a more or less free format.

Marcel STERE

2012-03-01

233

Design and development of direct drive generators for wind turbines  

International Nuclear Information System (INIS)

This paper discusses various options for wind generators in modern wind turbines without any gearbox. Various power converter configurations are also discussed. The design of modern and efficient variable speed generators is also proposed. The design of a novel permanent magnet generator is also given. (author)

2010-12-02

234

Damping Wind and Wave Loads on a Floating Wind Turbine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Christiansen, Sřren; Bak, Thomas; Knudsen, Torben

2013-01-01

235

Turbulent flow simulation over ice-accreted wind turbine blades  

Energy Technology Data Exchange (ETDEWEB)

This presentation reported on the results of a numerical and experimental research project on the effect of ice accretion on wind turbines. The study involved optimization of de-icing procedures as well as prediction of performance reduction in aerodynamics of iced airfoils. The purpose of the project was to analyze the impact of ice accretion on a wind turbine performance simulating the flow around clean and iced NACA 63-415 airfoils using the commercial package Fluent. The presentation outlined the problems caused by ice accreted over wind turbine blades and de-icing systems. The numerical model and results were also presented. The study proposed the most appropriate turbulence model to be used for airfoils with very large separated regions to determine the aerodynamic performance of iced airfoils and therefore to predict the production loss of a wind turbine during icing events. tabs., figs.

Villalpando, F.; Reggio, M. [Ecole Polytechnique, Montreal, PQ (Canada); Ilinca, A. [Quebec Univ., Rimouski, PQ (Canada). Wind Energy Group

2009-07-01

236

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.

Francesc Pozo

2012-08-01

237

Stability simulation of wind turbine systems  

Energy Technology Data Exchange (ETDEWEB)

A simulation and digital computer modeling effort is described in which a wind turbine-generator system is adapted for stability evaluation using a large scale transient stability computer program. Component models of the MOD-2 wind generator system are described and their digital model equations are provided. A versatile wind velocity model is described, which provides the capability of simulating a wide variety of wind variations, in addition to the usual network disturbances. Computed results obtained from runs of the enhanced stability program are provided that illustrate the wind turbine-generator system dynamic performance for changes in wind velocity.

Anderson, P.M.; Bose, A.

1983-12-01

238

Urban wind turbines. Guidelines for small wind turbines in the built environment  

International Nuclear Information System (INIS)

The objective of the WINEUR project (Wind Energy Integration in the Urban Environment) is to determine the deployability of small wind turbines in built environments while identifying the current significant constraints and possible solutions. The purpose of this document is to Inform the stakeholders about the state of the development of small wind turbines for the built environment; Provide practical guidelines to actors dealing with installation of small wind turbines in urban areas; and Provide recommendations for future products and for market development

2007-01-01

239

The small wind turbine field lab extensive field tests for small wind turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper describes the research possibilities at the Small Wind Turbine Field Lab and the involved research groups of Ghent University, covering different aspects of a small wind energy system. In contrast to large and medium-sized wind turbines, small wind turbines are still plagued by relatively high production and purchase costs, and low reliability and energy yield. Furthermore, most of them have not been subjected to a field test program. Power-Link, the energy knowledge platform of Gh...

Wyngene, Karel; Laveyne, Joannes; Kooning, Jeroen; Stockman, Kurt; Sergeant, Peter; Paepegem, Wim; Botteldooren, Dick; Maeyer, Jeroen; Eetvelde, Greet; Vandevelde, Lieven

2013-01-01

240

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

 
 
 
 
241

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

242

Economics of large wind turbine generators  

Energy Technology Data Exchange (ETDEWEB)

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

Oplinger, J.L.

1982-06-01

243

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

244

Performance methods (again ). [Wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The possibilities are examined of being able to continue using the type of method for performance/force calculation that is now generally being applied, with modifications. The attraction in blade element/momentum theory lies in the simplicity and speed of calculation. This should be viewed in comparison with vortex wake representation, which take up considerable computer time. The measurements were conducted in a low speed wind tunnel at KTH, The Royal Institute of Technology, in Stockholm. The models had a diameter of 25 cm suggesting that extreme care should be taken when Reynold's number (Re) effects are important and the data is to be used for larger machines. The shaft torque was absorbed by a small generator with a controllable dump load device allowing the desired RPM and/or power extraction. In the cases studied here the power coefficient was about 0.35. The wake was traversed with hot wire probes allowing the wake cross section to be mapped in detail concerning velocity and turbulence intensity. The main purpose of the investigation at KTH was to assess the wake speed deficiency for wind turbine clusters where the important issue is wake speed recovery and turbulence. In performance calculations the so called tip correction factor depends strongly on the helix angle assumed. T.Theodorsen, in this ''Theory of Propellers'', McGraw-Hill 1948, suggests that all geometry pertinent to be propeller can more conveniently be referred to the ''Trefftz' Plane''. Applying this idea to a wind turbine means that the apparent tip speed ratio (or helix angle) in the wake be used in place of the nominal tip speed ratio. The conclusion from some numerical exercises suggests that the tip speed ratio taken at the disk, gives better agreement with measurements. The singular tip vortex may be used, rather than some screw surface form which induction emanates. (AB).

Montgomerie, B. (The Aeronautical Research Institute of Sweden (SE))

1989-01-01

245

Challenges for large wind turbine blades  

Digital Repository Infrastructure Vision for European Research (DRIVER)

With global climate problems receiving increasingly international political attention,most European nations are looking for sources of renewable energy. Wind turbines area promising source of renewable energy and their numbers have steadily increasedsince the introduction of the modern wind turbine in the 1970s. The largest units todayhave a rated power of 7 MW and blades ranging up to 62.5 m in length. Offshore windturbines have access to stronger winds with less turbulence, thereby increasi...

Ho?yland, Jo?rg

2010-01-01

246

Low frequency noise and wind turbines  

International Nuclear Information System (INIS)

Concerns have been raised in the UK that noise radiated from wind Turbines contains sufficiently high levels of low frequency energy that may pose a threat to human health. It was suggested that symptoms included nausea, headaches and anxiety. This document, issued by the British Wind Energy Association (BWEA), provides information on the issue of low frequency noise and wind turbines, based on current knowledge. (author)

2005-01-01

247

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

248

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 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 fo...

Sřrensen, John Dalsgaard

2007-01-01

249

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

250

Wave Disturbance Reduction of a Floating Wind Turbine Using a Reference Model-based Predictive Control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Floating wind turbines are considered as a new and promising solution for reaching higher wind resources beyond the water depth restriction of monopile wind turbines. But on a floating structure, the wave-induced loads significantly increase the oscillations of the structure. Furthermore, using a controller designed for an onshore wind turbine yields instability in the fore-aft rotation. In this paper, we propose a general framework, where a reference model models the desired closed-loop beha...

Christiansen, Sřren; Tabatabaeipour, Seyed Mojtaba; Bak, Thomas; Knudsen, Torben

2013-01-01

251

Optimization and Control of a Variable Speed Wind Turbine with a Permanent Magnet Synchronous Generator  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this paper is to propose a control strategy and also analyse a fairly typical configuration of a wind turbine generating system connected with permanent magnet synchronous generator under varying speed. To reduce output power variations in wind turbine generating system, pitch angle controller of wind turbine has been used broadly. When the wind speed crosses the rated speed pitch angle controller become s active and control the power and speed to their rated values. To obtain this...

2013-01-01

252

European wind turbine standards 2 (EWTS-2)  

Energy Technology Data Exchange (ETDEWEB)

A summary is given of the main results of the European Wind Turbine Standards II project. EWTS-II was completed in 1998 and included investigations on: 1) wind farms-wind field and turbine loading; 2) complex terrain and fatigue loading; 3) extreme wind conditions; 4) quantification of failure probabilities; 5) integration of blade tests in design; 6) power performance in complex terrain; 7) site evaluation. In addition to these scientific evaluations, the EWTS-II participants established an organization of qualified measuring institute in the field of wind energy, the MEASNET organization. MEASNET unified measurement procedures of the participating institutes and guarantees qualified measurements and mutual acceptance among its members. (LN)

Pierik, J.T.G.; Dekker, J.W.M.; Braam, H. [and others

1999-03-01

253

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

254

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

255

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

256

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.

He Bin

2013-01-01

257

Soft yaw drives for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Soft yaw drives have many advantages over conventional yaw (azimuth) drives for wind turbines. The need for yaw brakes disappears and the yawing moments generally decrease considerably. The introduction of damping is beneficial for the wind turbine system as s whole and is one way to deal with lateral tower oscillation and blade edge oscillations. Soft yaw drives are available as packages composed from standard components, which is beneficial for the life cycle cost of the wind turbine system, and have been certified by the main certification bodies. (orig.)

Engstroem, S. [Aegier Konsultant AB (Sweden)

2001-02-01

258

Optimization of Wind Turbine Airfoils/Blades and Wind Farm Layouts  

Science.gov (United States)

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

Chen, Xiaomin

259

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

260

Study on wind turbine arrangement for offshore wind farms  

DEFF Research Database (Denmark)

In this paper, the separation distance between two neighboring offshore wind turbines has been carried out by using the Actuator Line/Navier-Stokes technique developed at the Technical University of Denmark (DTU). Under offshore atmospheric conditions, Large Eddy Simulation has been performed for two Tjæreborg 2 MW wind turbines in tandem with separation distances of 4D, 5D, 6D, 7D, 8D and 10D at the design wind speed of 10 m/s. The power performance of the wake turbine showed to be about 23% of the first turbine at a separation distance of 4D while its performance reached about 50% at 7D due to the turbulence mixing. This study hints that the optimal separation distance between neighboring turbines for offshore wind farms should be 7 rotor diameters.

Shen, Wen Zhong; Mikkelsen, Robert Flemming

2011-01-01

 
 
 
 
261

Modal testing of advanced wind turbine systems  

Energy Technology Data Exchange (ETDEWEB)

The US Department of Energy (DOE), in conjunction with the US wind industry, is supporting the development of technology for advanced, higher efficiency wind energy conversion systems. Under the Advanced Wind Turbine (AAWT) Program, the DOE, through the National Renewable Energy Laboratory (NREL), will assist US industry in incorporating advanced wind turbine technology into utility-grade wind turbines. As part of the AWT Program, NREL is conducting a range of activities aimed at assisting the wind industry with system design analysis and testing. One major activity is NREL`s Full System Model Testing (FSMT) task. In 1993 and 1994, NREL`s FSMT team conducted model surveys on several wind turbine systems developed by industry, including Atlantic Orient Corporation`s AOC 15/50, R. Lynette and Associates` AWT-26 P1, and Carter Wind Turbines Incorporated`s CWT-300. This paper describes how these model surveys were carried out and how industry and NREL wind researchers used the experimental results to validate their analytical models.

Osgood, R.M. [National Renewable Energy Laboratory, Golden, CO (United States). National Wind Technology Center

1995-09-01

262

Turbine configurations using wind and solar power  

Energy Technology Data Exchange (ETDEWEB)

A power system comprises structures which capture wind and solar energy to drive turbines for generating power. The structures can assume different forms, some intended to operate only from wind power. All in common, however, have lower air intake means which can accept the wind from any direction, air passageways that conduct the air upward through turbines, and venturi-assisted upper air exhaust vents which discharge the air downwind. Structures intended to operate on solar power in addition to wind have generally transparent sun-facing outer surfaces to admit solar radiation into the air passageways, a heat absorbing and transferring means inside the air passageways, and sufficient height that the solar heated air will rise with adequate velocity to operate the turbines. The invention includes an air inlet louver configuration which permits free entry of normal winds, but restricts entry of winds that have excessive force.

Schmugge, F.K.

1982-03-09

263

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

2012-01-01

264

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

265

Airfoil characteristics for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Airfoil characteristics for use in the Blade Element Momentum (BEM) method calculating the forces on Horizontal Axis Wind Turbines (HAWT) are derived by use of systematic methods. The investigation and derivation of the airfoil characteristics are based on 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 rotor with 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 a good 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 CFD computations and 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 of power 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 CFD computations, 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 for 2D 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. The different systematic methods show the importance 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 blade compared to 2D wind tunnel measurements. (au)

Bak, C.; Fuglsang, P.; Soerensen, N.N.; Aagaard Madsen, H. [Risoe National Lab., Roskilde (Denmark); Wen Zhong Shen; Noerkaer Soerensen, J. [Technical Univ. of Denmark, Lyngby (Denmark)

1999-03-01

266

Assessment of tonal noise from wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The significance of tonal components in noise emissions from wind turbines is discussed. The application of standard tonal assessment methods is reviewed together with the principle differences between methods and some potential areas of difficulty. (Author)

McKenzie, A.R. [Hayes McKenzie Partnership (United Kingdom)

1995-12-31

267

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

268

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

269

Lubricants : the lifeblood of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

With the significant investments in wind turbine equipment, companies need to exercise due diligence when it comes to the types of lubricants and fluids used. Mechanical and equipment issues can often be eliminated with improved maintenance practices and the appropriate selection of lubricants. This presentation discussed lubricants as being the lifeblood of wind turbines. The presentation first provided an overview and discussed wind turbine trends and application trends. The technical aspects of fluid formation were presented. Lubrication maintenance practices and oil monitoring were discussed. Last, key industry tests, and OEM specifications for bearings, gearboxes, and wind turbines were identified. It was concluded that improved maintenance practices in combination with the correct lubricant selection can address several operating problems. figs.

Tremblay, Y. [Petro-Canada, Calgary, AB (Canada)

2009-07-01

270

Wind Turbine Test Danwin 23 Prototype.  

Science.gov (United States)

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

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

1988-01-01

271

Wind Turbine Test Micon 55 KW.  

Science.gov (United States)

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

T. Friis Pedersen

1986-01-01

272

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

273

Slotted Blades Savonius Wind Turbine Analysis by CFD  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper a new bucket configuration for a Savonius wind generator is proposed. Numerical analyses are performed to estimate the performances of the proposed configuration by means of the commercial code COMSOL Multiphysics® with respect to Savonius wind turbine with overlap only. Parametric analyses are performed, for a fixed overlap ratio, by varying the slot position; the results show that for slot positioned near the blade root, the Savonius rotor improves performances at low tip spe...

Andrea Alaimo; Antonio Esposito; Alberto Milazzo; Calogero Orlando; Flavio Trentacosti

2013-01-01

274

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.

2012-04-01

275

Modal Testing of a Rotating Wind Turbine.  

Science.gov (United States)

A testing technique has been developed to measure the modes of vibration of a rotating vertical-axis wind turbine. This technique has been applied to the Sandia Two-Meter Turbine, where the changes in individual modal frequencies as a function of the rota...

T. G. Carne A. R. Nord

1982-01-01

276

Flicker Mitigation by Individual Pitch Control of Variable Speed Wind Turbines With DFIG  

DEFF Research Database (Denmark)

Due to the wind speed variation, wind shear and tower shadow effects, grid connected wind turbines are the sources of power fluctuations which may produce flicker during continuous operation. This paper presents a model of an MW-level variable-speed wind turbine with a doubly fed induction generatorto investigate the flicker emission and mitigation issues. An individual pitch control (IPC) strategy is proposed to reduce the flicker emission at different wind speed conditions. The IPC scheme is proposed and the individual pitch controller is designed according to the generator active power and the azimuth angle of the wind turbine. The simulations are performed on the NREL (National Renewable Energy Laboratory) 1.5-MW upwind reference wind turbine model. Simulation results show that damping the generator active power by IPC is an effective means for flicker mitigation of variable speed wind turbines during continuous operation.

Zhang, Yunqian; Chen, Zhe

2014-01-01

277

Aerodynamical noise from wind turbine generators  

International Nuclear Information System (INIS)

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

278

Preliminary wind tunnel tests on the pedal wind turbine  

Science.gov (United States)

High solidity-low speed wind turbines are relatively simple to construct and can be used advantageously in many developing countries for such direct applications as water pumping. Established designs in this class, such as the Savonius and the American multiblade rotors, have the disadvantage that their moving surfaces require a rigid construction, thereby rendering large units uneconomical. In this respect, the pedal wind turbine recently reported by the author and which incorporates sail type rotors offers a number of advantages. This note reports preliminary results from a series of wind tunnel tests which were carried out to assess the aerodynamic torque and power characteristics of the turbine.

Vinayagalingam, T.

1980-06-01

279

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 ice conditions. Based upon the flow field calculation and the droplet collision efficiency, the rate and shape of accreted ice was simulated at different atmospheric temperatures. Results indicat...

Muhammad S Virk, Matthew C. Homola

2012-01-01

280

Resonant vibration control of wind turbine blades  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ae...

Svendsen, Martin Nymann; Krenk, Steen; Hřgsberg, Jan Becker

2010-01-01

 
 
 
 
281

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

282

Wind turbine measurements for noise source indentification  

International Nuclear Information System (INIS)

This report summarises the results of a study developing a method of measuring and analysing noise from a wind turbine that provides repeatability and can be used to obtain data on noise, vibration, weather conditions and wind turbine operation. The experimental setup is described, and the overall level analysis, and the analyses of mechanical and aerodynamic noise are examined. The effects of turbulence on noise, and investigation of blade swish are discussed

1999-01-01

283

Guidelines for design of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The guidelines for design of wind turbines have been developed with an aim to compile into one book much of the knowledge about design and construction of wind turbines that has been gained over the past few years. This applies to knowledge achieved from research projects as well as to knowledge resulting from practical design experience. In addition, the various rules and methods required for type approval within the major markets.for the wind turbine industry form a basis for the guidelines, with emphasis on the international standards for wind turbines given by the International Electrotechnical Commission, IEC. The objective is to provide guidelines, which can be used for design of different types of wind turbines in the future. The guidelines provide recommendations and guidance for design together with application-oriented solutions to commonly encountered design problems. The guidelines can be used by wind turbine manufacturers, certifying authorities, and wind turbine owners. The guidelines will also be useful as an introduction and tutorial for new technical personnel and as a reference for experienced engineers. The guidelines are available as a printed book in a handy format as well as electronically in pdf format on a CD-ROM. The development of the guidelines is the result of a joint effort between Det Norske Veritas and Riso National Laboratory. The development has been founded by Danish Energy Agency, Det Norske Veritas and Risoe National Laboratory. These guidelines for design of wind turbines have been thoroughly reviewed by internal and external experts. However, no warranty, expressed or implied, is made by Det Norske Veritas and Risoe National Laboratory, as to the accuracy or functionality of the guide- lines, and no responsibility is assumed in connection therewith. (au)

NONE

2001-07-01

284

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

285

Passively cooled direct drive wind turbine  

Energy Technology Data Exchange (ETDEWEB)

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

286

A coherent laser Doppler wind profiler for the active control of wind turbines  

Science.gov (United States)

A low cost design concept for Fibre-based Coherent Laser Doppler Wind Profiler is presented for supporting an active pitch control of Wind Turbines (WTs). The system is based on a 1.5?m Continuous-Wave (CW) semiconductor laser source plus an erbium-doped fibre amplifier (EDFA) with an output power of 1W. A coherent detection method is used for Doppler frequency measurement. In addition, a concept of wind turbine predictive pitch control system is proposed for reducing the damage caused by wind turbulence. A mathematical simulation and the experimental result based on a lab setup are presented to show the calibration of such a system.

Shinohara, L.; Bogatscher, S.; Heussner, N.; Umesh-Babu, H.; Brunet, M.; Stork, W.

2012-02-01

287

Maximum Output Power Tracking of Wind Turbine Using Intelligent Control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Muldi Yuhendri; Mochamad Ashari; Mauridhi Hery Purnomo

2011-01-01

288

Dynamic response of a floating offshore wind turbine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The ever increasing demand for renewable energy, combined with limited areas suitable for large wind farms, has put focus on the development of floating wind turbines. In this thesis the dynamic response of a floating wind turbine, subjected to forces from wind and waves, is analyzed. The wind turbine is of a spar buoy design, similar to Statoil's Hywind project. Simulations with two main type of load cases were run, based on the international offshore wind turbine standard IEC 61400-3. These...

Střlsmark, Rasmus

2010-01-01

289

Wind turbine SCADA alarm analysis for improving reliability  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Previous research for detecting incipient wind turbine failures, using condition monitoring algorithms, concentrated on wind turbine Supervisory Control and Data Acquisition (SCADA) signals, such as power output, wind speed and bearing temperatures, using power-curve and temperature relationships. However, very little research effort has been made on wind turbine SCADA alarms. When wind turbines are operating in significantly sized wind farms, these alarm triggers are overwhelming for operato...

Qiu, Y. N.; Feng, Y. H.; Tavner, P. J.; Richardson, P.; Erdos, G.; Chen, Bindi

2012-01-01

290

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

291

Danish wind turbines - an industrial success story  

Energy Technology Data Exchange (ETDEWEB)

Danish wind turbines have a market share of half the world market with a turnover of some 450 million GBP (1996), out of a total market of 1,000 million. Since 1993-1995 the wind industry has been growing at a rate of 50 per cent per annum, and growth rates of 10 to 20 per cent per year are foreseen for the period up to year 2000. In the 12-months up to October 1996, the Danish wind turbine industry supplied turbines with a rated capacity of 600 Megawatts (MWE), equivalent to one large nuclear or coal-fired power station block per year. Wind turbine manufacturing, maintenance, installation and consultancy services account for some 9,000 jobs in Denmark, while component supplies and installation of Danish turbines currently creates another 6,000 jobs worldwide. Wind energy employs some 30,000 people worldwide, and 20,000 in the European Union (1996). While turbine manufacturing tends to be concentrated in Denmark, Germany, Spain and the Netherlands, component manufacturers and service suppliers are spread all over Europe. The UK Wind Industry is primarily service related, being internationally recognised for its project development and engineering services. (author)

Krohn, S. [Danish Wind Turbine Manufacturers` Association (Denmark)

1996-11-01

292

A Method for Modeling of Floating Vertical Axis Wind Turbine  

DEFF Research Database (Denmark)

It is of interest to investigate the potential advantages of floating vertical axis wind turbine (FVAWT) due to its economical installation and maintenance. A novel 5MW vertical axis wind turbine concept with a Darrieus rotor mounted on a semi-submersible support structure is proposed in this paper. In order to assess the technical and economic feasibility of this novel concept, a comprehensive simulation tool for modeling of the floating vertical axis wind turbine is needed. This work presents the development of a coupled method for modeling of the dynamics of a floating vertical axis wind turbine. This integrated dynamic model takes into account the wind inflow, aerodynamics, hydrodynamics, structural dynamics (wind turbine, floating platform and the mooring lines) and a generator control. This approach calculates dynamic equilibrium at each time step and takes account of the interaction between the rotor dynamics, platform motion and mooring dynamics. Verification of this method is made through model-to-model comparisons. Finally, some dynamic response results for the platform motion are presented as an example for application of this method.

Wang, Kai; Hansen, Martin Otto Laver

2013-01-01

293

Fatigue Analysis of Column-Brace Connection in a Semi-submersible Wind Turbine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The importance of offshore renewable energy from wind is expected to increase in the future. Most offshore wind turbines are currently installed in shallow water up to 50 meter water depth on bottom mounted substructures. To harvest more wind energy at deeper waters, offshore floating support structures are needed. Semi-submersible floating wind turbine is one of the proposed floating concepts. Under simultaneous wind and wave loads, fatigue might be an important design consideration. Study o...

Fredheim, Řrjan

2012-01-01

294

Design Oriented Aerodynamic Modelling of Wind Turbine Performance  

International Nuclear Information System (INIS)

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

2007-07-01

295

Optimization of power output from wind turbines  

Energy Technology Data Exchange (ETDEWEB)

In high-wind climates, the standard wind turbine is not optimized relative to the wind speed distribution, i.e. the machine extracts a lower fraction of the energy available in the wind than theoretically possible. It is demonstrated by an example that the over-all efficiency may be as low as 15% while under other circumstances a modern wind turbine is expected to utilize more than 30% of the wind energy. Thus, for the same external geometry of the wind turbine, the output may be doubled. The basic mean to increase the over-all efficiency in high-wind speed climates is to increase the rpm of the machine (the present trend in wind turbine optimization is actually the opposite: increasing the swept area by means of blade extenders together with decreased rpm). For stall regulated machines, the consequences of increased rpm include higher rated power and larger aerodynamic loads. The paper analyses the technical impact in terms of increase in materials' consumption and briefly indicates the economic benefits obtained by the suggested improvement of efficiency. The potential cost effectiveness is found to be significant. (author).

Frandsen, S.; Hauge Madsen, P. (Department of Meteorology and Wind Energy, Risoe National Lab., Roskilde (DK))

1989-10-01

296

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 during disturbances, and dynamic behaviours of power system with large wind power integration. The work in this thesis is in a down-up approach, starting with concepts for individual wind turbines, i...

Zhou, Y.

2009-01-01

297

Analysis of Counter-Rotating Wind Turbines  

International Nuclear Information System (INIS)

This paper presents a study on the performance of a wind turbine with two counter-rotating (CRWT) rotors. The characteristics of the two counter-rotating rotors are on a 3-bladed Nordtank 500 kW rotor. The analysis has been carried out by using an Actuator Line technique implemented in the Navier-Stokes code EllipSys3D. The analysis shows that the Annual Energy Production can be increased to about 43.5 %, as compared to a wind turbine with a single rotor. In order to determine the optimal settings of the CRWT turbine, parameters such as distance between two rotors and rotational speed have been studied

2007-07-01

298

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

Science.gov (United States)

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

Wu, Yu-Ting; Porté-Agel, Fernando

2014-05-01

299

Infrasound emission generated by wind turbines  

Science.gov (United States)

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

Ceranna, Lars; Pilger, Christoph

2014-05-01

300

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

 
 
 
 
301

Robust and Fault-Tolerant Linear Parameter-Varying Control of Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 paper we design and compare multiple linear parameter-varying (LPV) controllers, designed using a proposed method that allows the inclusion of both faults and uncertainties in the LPV controller design. We specifically consider a 4.8 MW, variable-speed, variable-pitch wind turbin...

Sloth, Christoffer; Esbensen, Thomas; Stoustrup, Jakob

2011-01-01

302

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

2010-06-01

303

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

304

Draft-circular on wind turbines. Concept-circulaire wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Criteria for providing licenses to build and operate a wind turbine are surveyed. Factors to consider are: characteristics of the landscape, density of population, town and country planning, environmental aspects (birds), safety and nuisance. National regulations for wind turbines will simplify licensing procedures and improve legal security.

1983-01-01

305

Wind turbulence inputs for horizontal axis wind turbines  

Science.gov (United States)

Wind turbine response characteristics in the presence of atmospheric turbulence was predicted using two major modeling steps. First, the important atmospheric sources for the force excitations felt by the wind turbine system were identified and characterized. Second, a dynamic model was developed which describes how these excitations are transmitted through the structure and power train. The first modeling step, that of quantifying the important excitations due to the atmospheric turbulence was established. The dynamic modeling of the second step was undertaken separately.

Holley, W. E.; Thresher, R. W.; Lin, S. R.

1981-01-01

306

Technical Description of the NIBE Wind Turbines.  

Science.gov (United States)

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

1981-01-01

307

Vertical Axis Wind Turbine Control Strategy.  

Science.gov (United States)

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...

G. M. McNerney

1981-01-01

308

Wind turbines - localisation strategy in Denmark  

International Nuclear Information System (INIS)

Sites for 1500 MW wind power in Denmark by 2005 will be found through a decentralized planning process with public participation. The wind turbines will be sited in parks and clusters in order to secure good economy and satisfactory locations in the landscape. (author)

1994-08-01

309

Investigations of a building-integrated ducted wind turbine module  

Science.gov (United States)

So far, wind energy has not played a major role in the group of technologies for embedded generation in the built environment. However, the wind flow around conventional tall buildings generates differential pressures, which may cause an enhanced mass flow through a building-integrated turbine. As a first step, a prototype of a small-scale ducted wind turbine has been developed and tested, which seems to be feasible for integration into the leading roof edge of such a building. Here an experimental and numerical investigation of the flow through building-integrated ducting is presented. Pressure and wind speed measurements have been carried out on a wind tunnel model at different angles of incident wind, and different duct configurations have been tested. It was confirmed that wind speeds up to 30% higher than in the approaching freestream may be induced in the duct, and good performance was obtained for angles of incident wind up to ±60°. The experimental work proceeded in parallel with computational fluid dynamics (CFD) modelling. The geometry of the system was difficult to represent to the required level of accuracy, and modelling was restricted to a few simple cases, for which the flow field in the building-integrated duct was compared with experimental results. Generally good agreement was obtained, indicating that CFD techniques could play a major role in the design process. Predicted power of the proposed device suggests that it will compare favourably with conventional small wind turbines and photovoltaics in an urban environment.

Dannecker, Robert K. W.; Grant, Andrew D.

2002-01-01

310

Dynamic Stall Model for Wind Turbine Airfoils  

DEFF Research Database (Denmark)

 A model is presented for aerodynamic lift of wind turbine profiles under dynamic stall. The model combines memory delay effects under attached flow with reduced lift due to flow separation under dynamic stall conditions. The model is based on a backbone curve in the form of the static lift as a function of the angle of attack. The static lift is described by two parameters, the lift at fully attached flow and the degree of attachment. A relationship between these parameters and the static lift is available from a thin plate approximation. Assuming the parameters to be known during static conditions, nonstationary effects are included by three mechanisms: a delay of the lift coefficient of fully attached flow via a second-order filter, a delay of the development of separation represented via a first-order filter, and a lift contribution due to leading edge separation also represented via a first-order filter. The latter is likely to occur during active pitch control of vibrations. It is shown that all included effects can be important when considering wind turbine blades. The proposed model is validated against test data from two load cases, one at fully attached flow conditions and one during dynamic stall conditions. The proposed model is compared with five other dynamic stall models including, among others, the Beddoes-Leishman model and the ONERA model. It is demonstrated that the proposed model performs equally well or even better than more complicated models and that the included nonstationary effects are essential for obtaining satisfactory results. Finally, the influence of camber and thickness distribution on the backbone curve are analysed. It is shown that both of these effects are adequately accounted for via the static input data.

Larsen, Jesper Winther; Nielsen, Søren R.K.

2007-01-01

311

Power Electronics for the Next Generation Wind Turbine System  

DEFF Research Database (Denmark)

The wind power generation has been steadily growing both for the total installed capacity and for the individual turbine size. Due to much more significant impacts to the power grid, the power electronics, which can change the behavior of wind turbines from an unregulated power source to an active generation unit, are becoming crucial in the wind turbine system. The objective of this project is to study the power electronics technology used for the next generation wind turbines. Some emerging challenges as well as potentials like the cost of energy and reliability are going to be addressed. First several potential converter topologies and power semiconductor devices for the future wind power application are presented in respect to the advantages/drawbacks. And then the criteria for evaluating the wind power converter are generally discussed, where the importance of thermal stress in the power semiconductors is emphasized and a multidisciplinary approach for the stress analysis is introduced. Based on the proposed criteria and tools, the electrical and thermal behaviors of wind power converters are investigated under both normal and fault conditions, where the factors of wind speeds, grid codes, converter controls and grid conditions are taken into account. In order to relieve the electrical and thermal stress of the converter in wind turbine system, some new control methods and concepts are thereby proposed. In Chapter 4 a thermal control concept which utilizes the reactive power is used to stabilize the thermal excursion under wind gust. In Chapter 5 a series of special modulation methods which can achieve better thermal loading of power devices under grid faults are introduced. Also in Chapter 5 a series of power control strategies utilizing the zero sequence current are presented to achieve better control performance under the unbalanced AC source. It is concluded that power electronics will play more important role and regulate all the generated power in the next generation wind turbine system. In this case, the stress in the converter components becomes more critical because the power conversion is pushed to multi-MW level with high power density requirement. It has also been revealed that thermal stress in the power semiconductors is closely related to many determining factors in the wind power application like the reliability, cost, power density, etc. therefore it is an important performance for the next generation wind power converter. It is found that the thermal behaviors of wind power converter could be rather adverse under some required operating conditions. On the other hand it is also possible to improve the thermal behaviors by many aspects like the smart control, special modulation, advanced modeling, as well as new converter designs.

Ma, Ke

2013-01-01

312

UNSTEADY SIMULATION OF FLOW IN MICRO VERTICAL AXIS WIND TURBINE  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Though wind turbines and windmills have been used for centuries, the application of aerodynamics technology to improve reliability and reduce costs of wind-generated energy has only been pursued in earnest for the past 40 years. Today, wind energy is mainly used to generate electricity. Wind is a renewable energy source. Power production from wind turbines is affected by certain conditions: wind speed, turbine speed, turbulence and the changes of wind direction. These conditions are not alway...

Bayeul-laine, Annie-claude; Bois, Ge?rard

2010-01-01

313

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

International Nuclear Information System (INIS)

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.

2012-12-01

314

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

315

Common fallacies in wind turbine design  

Energy Technology Data Exchange (ETDEWEB)

As independent wind energy consultants, Garrad Hassan have had wide experience of wind turbine designs over a number of years (1, 2, 3 and multi-bladed rotors, pitch and stall regulation, constant speed and variable speed etc.). This paper is a review not of any specific designs but of aspects underlying design philosophy. In particular, a number of common fallacies about wind turbine design are discussed. These relate to scaling laws, energy trade-offs with rotor diameter, cheap blades for small machines and principles of lightweight design. (Author)

Jamieson, P. [Garrad Hassan and Partners Ltd., Glasgow (United Kingdom)

1998-07-01

316

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

International Nuclear Information System (INIS)

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

2012-05-01

317

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

Science.gov (United States)

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

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

2014-01-01

318

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

Science.gov (United States)

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

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

2014-01-01

319

New methods in wind turbine tower design  

Energy Technology Data Exchange (ETDEWEB)

The main consideration in this wind turbine tower analysis was the use of Finite Element Modelling (FEM) and Computational Fluid Dynamics modelling (CFD). For application, the first wind turbine installation was planned in the hilly region on the banks of the Danube, near Dunaujvaros, where wind speed measurements were recorded from the beginning of 1999. The topographical and wind speed measurement data were used as input for the pre-feasibility study. Flow around the tower was modelled with CFD, with the on-site wind measurement data used as inlet boundary condition for a dynamic system analysis. The aim was to find the most suitable height and cross section for tower design, considering the possible vibrations and torque. The results were verified with wind tunnel and vibration measurements on physical models. (author)

Horvath, G.; Toth, L. [Szent Istvan University (Hungary). Faculty of Mechanical Engineering

2001-07-01

320

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

 
 
 
 
321

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

322

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.

Aron Pujana-Arrese

2012-04-01

323

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

324

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

325

Modeling of soft-starters for wind turbine applications  

Energy Technology Data Exchange (ETDEWEB)

Gurrently, the directly connected squirrelcage induction generator is the most widely used in wind turbine applications. They are normally equipped with a soft-starter in order to avoid inrush currents. A new method, which uses switching functions to simulate different connection types for soft-starter-fed induction generators, is presented in this paper. An ABC/abc model of the induction machine including the deep-bar effect is also shown. Based on the proposed method some simulation results during the grid connection of a large induction machine in wind turbine applications are finally shown and demonstrates the new tools. (au)

Iov, F.; Hansen, A.D. [Risoe National Lab., Wind Energy Dept., Roskilde (Denmark); Blaabjerg, F.; Teodorescu, R. [Aalborg Univ., Inst. of Energy Technology, Aalborg (Denmark)

2003-07-01

326

Aspects in Formulating Mathematical Model of Wind Turbine  

Directory of Open Access Journals (Sweden)

Full Text Available The present paper explores the mathematical molding of the wind turbine and its influence on the subsequent stages. Specifically, the paper investigate the modeling of gear train of the wind turbine and distinguishes the difference in the approaches usually used to establish the mathematical model which is later has a significant impact on the design, characteristic and performance of the modeled system. Mainly two commonly used approached for the gear train systems are analyzed and discussed.  The main well know mechanisms are investigated in term of the most proposed assumptions to deal with the damping, shaft stiffness and inertia effect of the gear. This paper elucidates these concerns??????: ???, ????, ?????, ?? ?????, ?? ????, ????, ????, ????

Waleed Khalil Ahmed

2013-06-01

327

Aerodynamic research on wind turbines at NLR  

Energy Technology Data Exchange (ETDEWEB)

The paper is limited to flow calculations for a horizontal axis wind turbine in a constant homogeneous flow of wind. 3 aspects are considered: 1. The extension of an existing rotor blade method of calculation to a turbulent condition. 2. The development of a vortex method of calculation. This is compared with results from the 'blade element theory' and empirical results. 3. The investigation of wind guide stability for narrow guidance angles. (BR).

Vries, O. de

1985-03-01

328

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

329

Performance of fixed speed wind turbines under system frequency deviations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper studies the impact of system frequency deviations on the operation of fixed speed induction generators used in wind turbine generation systems(WTGS). It presents an analytic method to predict the angular speed, torque and current during and after a frequency disturbance. The proposed method can be used to evaluate the operation limits of the WTGS during frequency deviations.

Sumper, Andreas; Gomis Bellmunt, Oriol; Sudria? Andreu, Antoni; Villafafila Robles, Roberto; Rull Duran, Joan

2010-01-01

330

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

2011-01-01

331

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

332

Atmospheric stability affects wind turbine power collection  

International Nuclear Information System (INIS)

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)

2012-03-01

333

Atmospheric stability affects wind turbine power collection  

Science.gov (United States)

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.

Wharton, Sonia; Lundquist, Julie K.

2012-03-01

334

Grid integration impacts on wind turbine design and development  

DEFF Research Database (Denmark)

This paper presents an overall perspective on contemporary issues like wind power plants and grid integration. The purpose is to present and discuss the impacts of emerging new grid connection requirements on modern wind turbines. The grid integration issue has caused several new challenges to the wind turbine design and development. The survival of different wind turbine concepts and controls is strongly conditioned by their ability to comply with stringent grid connection requirements, imposed by utility companies. Beside its impact on the mechanical design and control of wind turbines, the grid integration aspect has also an effect on wind turbines' role in the power system, on wind turbine technologies' survival on the market, as well as on the wind turbines' loads. Over the last years, it became obviously, that there it is an increasing need for design and research of wind turbines based on an integrated design and control approach.

Hansen, Anca Daniela; Cutululis, Nicolaos Antonio

2009-01-01

335

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

336

Assessment and prediction of wind turbine noise  

International Nuclear Information System (INIS)

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

337

Wind Turbine Test. Wind Matic WM 17S.  

Science.gov (United States)

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

T. Friis Pedersen

1986-01-01

338

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

International Nuclear Information System (INIS)

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

2008-11-01

339

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

340

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

 
 
 
 
341

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

342

Turbine Interaction in Large Offshore Wind Farms. Wind Tunnel Measurements  

Energy Technology Data Exchange (ETDEWEB)

Large wind farms are to be expected in the coming decades. We are talking about farms of for example 20 times 20 turbines or larger. Of course it is of utmost importance to be able to predict the production of such farms accurately. However, little is known on cumulative effects of wind turbine wakes. Therefore this project studies the wind turbine interference and especially wake losses for larger offshore farms. The decrease of the wind speed in the wake of wind turbines can be compared to the frictional drag exerted to the planetary boundary layer by surface roughness. We calculated the effect to the boundary layer when the wind encounters a wind farm. The wind farm was implemented as a sudden change of the surface roughness. Our calculations showed that after an increase of the surface roughness, the wind speed was decreasing up to large distances downstream. Several wind farm models assume that equilibrium is reached after 5 rows of wind turbines, our model showed that it will take at least 10 rows before equilibrium is reached to some extent. This means that our classical models predict a too high power output for really large wind farms. In order to validate the results of the model we set up an experiment in the boundary layer tunnel of TNO, Apeldoorn. We designed and manufactured 30 wind turbines on a scale of 1:400. The turbines are 25 cm diameter and have a hub height of 25 cm. Our design philosophy has delivered rotors which are very similar to full scale rotors regarding the axial force and wake properties, however regarding the efficiency their performance is less. The power coefficient is about 0.30, while is can be between 0.45 and 0.50 for commercial rotors. In the wind tunnel the surface roughness (excluding that due to the wind turbines) was set to sea conditions: after scaling this was approximately 0.2 mm / 400. Sometimes the roughness was adapted to onshore circumstances as well. We installed several wind farms layouts and measured the wake losses and the effects on the boundary layer. The validation suggests that the wind velocity has not reached its equilibrium value after 5 rows, which indicates that the numerical model can be used for global studies of atmospheric flows above (and behind) large wind farms. The words 'suggests' and 'indicates' were used since the situation in the tunnel was different from the real situation in several aspects. For several reasons the interpretation of the results was difficult. Especially the accurate measurement of the wind speed was a difficulty. A way out for this accuracy problem was the application of differential measurements: we finally set up two farms next to each other in the tunnel. We can not rely on wind farm models that assume that the wind flow in a farm is stabilized after five rows of turbines. Many models will over predict production. We recommend that much attention is to be paid to improvement of the accuracy in the wind tunnel and to the organization of good experiments with actual farms in the field. Both suggestions have been implemented in successive projects, which already have been started.

Hegberg, T.; Corten, G.P.; Schaak, P. [ECN Wind Energy, Petten (Netherlands)

2004-08-01

343

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

344

Stochastic wind turbine control in multiblade coordinates  

DEFF Research Database (Denmark)

In this paper we consider wind turbine load attenuation through model based control. Asymmetric loads caused by the wind field can be reduced by pitching the blades individually. To this end we investigate the use of stochastic models of the wind which can be included in a model based individual pitch controller design. In this way the variability of the wind can be estimated and compensated for by the controller. The wind turbine model is in general time-variant due to its rotational nature. For this reason the modeling and control is carried out in so-called multiblade coordinates. A controller based on the H2 methodology is designed and tested in simulations.

Thomsen, Sven Creutz; Niemann, Hans Henrik

2010-01-01

345

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

346

A review of large wind turbine systems  

Science.gov (United States)

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

Selzer, H.; Lerner, J. I.

347

Optimization of wind farm turbines layout using an evolutive algorithm  

Energy Technology Data Exchange (ETDEWEB)

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)

Gonzalez, Javier Serrano; Santos, Jesus Riquelme; Payan, Manuel Burgos [Department of Electrical Engineering, Av. de los Descubrimientos, University of Sevilla, Sevilla (Spain); Gonzalez Rodriguez, Angel G. [Department of Electronic Engineering and Automatic, University of Jaen, Jaen (Spain); Mora, Jose Castro [Persan S.A., Sevilla (Spain)

2010-08-15

348

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)

2010-08-01

349

Transient EMF induced in LV cables due to wind turbine direct lightning strike  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a novel, easy to use, engineering method for determining the transient electromotive force (EMF) induced in low-voltage (LV) cables, connecting the wind turbine with a near-by transformer, in the event of direct lightning strike into the top of the wind turbine tower. Proposed method is based on the application of the travelling wave analysis onto the system consisted of wind turbine tower, earthing system of wind turbine, earthing system of near-by transformer station and LV cables connecting the wind turbine with associated transformer. Hence, this design gives rise to a complex, mutually connected, earthing system. Direct lightning strike to the wind turbine initiates a travelling wave process in the system consisted of lightning channel, wind turbine tower and earthing system of the wind turbine. Due to the transient nature of the observed phenomenon, current and voltage states at the earthing system as well as in the associated low-voltage cables are formed through the propagation and reflection of the accompanying travelling waves. Transient EMF induced in LV cables could endanger cable main insulation and insulation of the associated transformer LV winding. Developed theory is subsequently applied on the concrete wind turbine example. (author)

Sarajcev, Petar; Sarajcev, Ivan; Goic, Ranko [University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, Rudera Boskovica bb, HR-21000 Split (Croatia)

2010-04-15

350

Minimization of the effects of yaw oscillations in wind turbines  

Energy Technology Data Exchange (ETDEWEB)

Yaw (fishtail) oscillations in large wind turbines are minimized by damping provided by a drive motor connecting the turbine to the supporting tower therefore at, for example, a yaw bearing. The drive motor drives the wind turbine in yaw and maintains desired yaw settings of the turbine. The motor is also capable of being driven by yaw oscillations of the wind turbine and in being so driven, dissipates the energy of such oscillations.

Doman, G. S.

1985-05-07

351

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

2013-06-01

352

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

International Nuclear Information System (INIS)

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

353

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

354

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

355

Wind Turbine Gearbox Condition Monitoring with AAKR and Moving Window Statistic Methods  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Condition Monitoring (CM) of wind turbines can greatly reduce the maintenance costs for wind farms, especially for offshore wind farms. A new condition monitoring method for a wind turbine gearbox using temperature trend analysis is proposed. Autoassociative Kernel Regression (AAKR) is used to construct the normal behavior model of the gearbox temperature. With a proper construction of the memory matrix, the AAKR model can cover the normal working space for the gearbox. When the gearbox has a...

Peng Guo; Nan Bai

2011-01-01

356

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

Science.gov (United States)

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

Agrawal, Vineesh V.

357

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

Science.gov (United States)

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

G. M. Smith B. R. Clayton

1992-01-01

358

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

359

Recommended practices for wind turbine testing. Vol. 1  

Energy Technology Data Exchange (ETDEWEB)

This document describes the recommended practices for testing and reporting power performance characteristics of a single wind turbine. It provides a standard methodology, exclusively for comparing the energy production characteristics of wind turbines available in the market. (CLS).

Frandsen, S.; Maribo Pedersen, B. (eds.)

1990-07-01

360

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

2007-07-01

 
 
 
 
361

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

362

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

363

Methods of making wind turbine rotor blades  

Energy Technology Data Exchange (ETDEWEB)

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

364

Aerodynamic analysis of rotor-nacelle interactions for wind turbines  

International Nuclear Information System (INIS)

This paper presents a numerical method for investigating rotor-nacelle aerodynamic interactions of an horizontal axis wind turbine. The flowfield around the turbine and nacelle is described by the Reynolds averaged Navier-Stokes equations. The k - ? model has been chosen for the closure of time-averaged turbulent flow equations. The turbine is modeled using the actuator disk concept. Most of the nacelle region is represented by its real geometrical shape as wall boundary, except for the cooling system (radiator) of the electric generator which is modeled as a permeable surface with some prescribed pressure jump. An unstructured Control-Volume Finite Element Method has been developed to solve the resulting governing equations. The main purpose of this paper is to establish the relationship between the nacelle wind speed and free stream wind speed for an isolated turbine, in order to assess the impacts of the variation of some operational parameters (e.g. blade pitch angle changes) on this relationship. The simulation results have been compared with the experimental data (from typical a stall-controlled wind turbine rated more than 600kW and commercially available). In general, good agreements have been found proving the validity of the proposed method. It has been concluded that the accuracy of the predicted results depends mainly on the prescribed pressure jump across the permeable surface representing the generator cooling system. (author)

2002-06-09

365

Battery Voltage Stability Effects on Small Wind Turbine Energy Capture.  

Science.gov (United States)

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

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

2002-01-01

366

Siting of wind turbines near buildings and obstacles  

Energy Technology Data Exchange (ETDEWEB)

The background for this note is the description of job B-2 in research project: ''Siting of Wind Turbines near Buildings and Obstacles''. The scope of this work is to report measurements, carried out in the wind tunnel at DMI, and make a proposal to supplementary measurements. A model of a farm in scale 1:100 was studied in the boundary-layer wind tunnel. The change in the means velocity of the flow caused by the model was studied in simulated boundary layers, which corresponds to full-scale boundary layers. The report shows that it should be possible to measure the influence of a building on a wind turbine's power production in full-scale on the actual farm placed at Sjaellands Odde, Denmark. (author).

Ingham, P.

1987-10-01

367

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.

Yoonsu Nam

2012-06-01

368

Icing of wind turbines in Europe  

Energy Technology Data Exchange (ETDEWEB)

The main objective of the research program co-funded by the European Commission is the analysis of wind turbine operation under icing conditions within Europe. The increasing application of wind turbines in mountainous regions and in Northern Europe raised the questions which have been partly answered by the project`s results: Which weather conditions cause icing and at which sites do they occur, which types of ice accretion can influence wind turbine operation, and what are the influences on aerodynamics, loads, control system, energy output etc? In order to catalogue ice endangered sites a questionnaire has been distributed to concerned operators and manufacturers. Results from the inquiry have been evaluated in terms of occurrence of icing, types of ice and ice formation, as well as locations around the turbines where thrown off ice fragments were found. A map of Europe is presented, including the reported icing events from several countries covering from a few days to some weeks of operation under icing conditions. The inquiry also proved the assumptions for ice loads developed within the project to be conservative. Influences of icing on wind turbine loads are discussed and recommendations given with respect to interested parties such as manufacturers, certification bodies and operators. (Author)

Seifert, H. [Deutsches Windenergie-Institut, Wilhelmshaven (Germany); Tammelin, B. [Finnish Meteorological Institute, Helsinki (Finland)

1996-12-31

369

High Power Density Power Electronic Converters for Large Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In large wind turbines (in MW and multi-MW ranges), which are extensively utilized in wind power plants, full-scale medium voltage (MV) multi-level (ML) voltage source converters (VSCs) are being more preferably employed nowadays for interfacing these wind turbines with electricity grids. For these VSCs, high power density is required due to limited turbine nacelle space. Also, high reliability is required since maintenance cost of these remotely located wind turbines is quite high and these ...

Senturk, Osman Selcuk

2011-01-01

370

High Power Density Power Electronic Converters for Large Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In large wind turbines (in MW and multi-MW ranges), which are extensively utilized in wind power plants, full-scale medium voltage (MV) multi-level (ML) voltage source converters (VSCs) are being more preferably employed nowadays for interfacing these wind turbines with electricity grids. For these VSCs, high power density is required due to limited turbine nacelle space. Also, high reliability is required since maintenance cost of these remotely located wind turbines is quite high and these ...

Senturk, Osman Selcuk

2012-01-01

371

Power Electronics for the Next Generation Wind Turbine System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The wind power generation has been steadily growing both for the total installed capacity and for the individual turbine size. Due to much more significant impacts to the power grid, the power electronics, which can change the behavior of wind turbines from an unregulated power source to an active generation unit, are becoming crucial in the wind turbine system. The objective of this project is to study the power electronics technology used for the next generation wind turbines. Some emerging...

2013-01-01

372

Amplitude modulation of wind turbine noise  

CERN Multimedia

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

373

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 analyses examine how the fatigue loads differs from one wind profile to the next, which means it is actually the relative fatigue that is being calculated. There are a total of seven wind profiles i...

Stava, Ole Magnus

2012-01-01

374

Dynamic Response of Floating Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this thesis the extreme values of tension in the mooring lines on Hywind Demo is investigated. Hywind Demo is a floating wind turbine developed by Statoil ASA. The aim of the study is to evaluate the application of the environmental contour line method on the wind turbine. The environmental contour line method will be compared to a full long term analysis of the extreme response. It is expected that a full long term analysis will give a good estimates of the design loads and can be used to...

Neuenkirchen Godř, Sjur

2013-01-01

375

Wind turbine blade pitch control system  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The present invention provides an improvement for a wind turbine (20) having at least one blade (21) mounted on a hub (22) for controlled rotation about a blade axis (yb-yb) to vary the pitch of the blade relative to an airstream. The hub is mounted on a nacelle (23) for rotation about a hub axis (xh-xh). The wind turbine includes a main pitch control system for selectively controlling the pitch of the blade, and/or a safety pitch control system for overriding the main blade pitch control sys...

Potter, Benjamin Alexander; Nagasaki, Ryuichi; Shiga, Mamoru

2010-01-01

376

Error analysis in wind turbine field testing  

Energy Technology Data Exchange (ETDEWEB)

In wind turbine field testing, one of the most important issues is understanding and accounting for data errors. Extended dynamic testing of wind turbines requires a thorough uncertainty analysis and a regimen of quality assurance steps in order to preserve accuracy. Test objectives need to be identified to determine the accuracy requirements of any data measurement, collection, and analysis process. Frequently, the uncertainty analysis reveals that the major sources of error can be allowed for with careful calibration and signal drift tracking procedures. This paper offers a basis for the discussion and development of a repeatable and accurate process to track errors and account for them in data processing.

McNiff, B [McNiff Light Industries, Carlisle, MA (United States); Simms, D [National Renewable Energy Lab., Golden, CO (United States)

1994-08-01

377

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 K. Ebbesen

2011-10-01

378

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

379

Mod-2 wind turbine field operations experience  

Science.gov (United States)

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

Gordon, L. H.

1984-01-01

380

Impact of wind turbines on birdlife  

International Nuclear Information System (INIS)

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

 
 
 
 
381

Impact of wind turbines on birdlife  

Energy Technology Data Exchange (ETDEWEB)

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.

Benner, J.H.B.; Berkhuizen, J.C.; De Graaff, R.J.; Postma, A.D. (Consultants on Energy and Environment CEA, Rotterdam (Netherlands)); Hendriks, J.H.W. (Rijksuniversiteit Leiden (Netherlands))

1993-05-01

382

Measurements on large wind turbines  

Energy Technology Data Exchange (ETDEWEB)

In the following an overview about the activities of WINDTEST concerning power performance measurements on wind energy converters (WEC) of the MW-class is given. In addition wind measurement with cup anemometers and a sodar system are compared. (au)

Follrichs, U. [WINDTEST KWK GmbH, Kaiser-Wilhelm-Koog (Germany)

1997-12-31

383

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

384

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

385

A geographic analysis of wind turbine placement in Northern California  

International Nuclear Information System (INIS)

The development of new wind energy projects requires a significant consideration of land use issues. An analytic framework using a Geographic Information System (GIS) was developed to evaluate site suitability for wind turbines and to predict the locations and extent of land available for feasible wind power development. The framework uses rule-based spatial analysis to evaluate different scenarios. The suitability criteria include physical requirements as well as environmental and human impact factors. By including socio-political concerns, this technique can assist in forecasting the acceptance level of wind farms by the public. The analysis was used to evaluate the nine-county region of the Greater San Francisco Bay Area. The model accurately depicts areas where large-scale wind farms have been developed or proposed. It also shows that there are many locations available in the Bay Area for the placement of smaller-scale wind turbines. The framework has application to other regions where future wind farm development is proposed. This information can be used by energy planners to predict the extent that wind energy can be developed based on land availability and public perception

2006-10-01

386

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

2010-12-01

387

Wind turbine pitch control using ICPSO-PID algorithm  

DEFF Research Database (Denmark)

For the traditional simplified first-order pitch-control system model, it is difficult to describe a real dynamic characteristic of a variable pitch action system, thus a complete high order mathematical model has to be developed for the pitch control of wind turbine generation (WTG). In the paper, a pitch controller was designed based on power and wind speed and by considering the inertia and delay characteristics of a pitch-control system to achieve a constant power output when a wind speed was beyond the rated one. A novel ICPSO-PID control algorithm was proposed based on a combination of improved cooperative particle swarm optimization (ICPSO) and PID, subsequently, it was used to tune the pitch controller parameters; thus the difficulty in PID tuning was removed when a wind speed was above the rated speed. It was indicated that the proposed optimization algorithm can tune the pitch controller parameters quickly; and the feed-forward controller for wind speed can improve dynamics of a pitch-control system; additionally the power controller can allow a wind turbine to have a constant power output as a wind speed is over the rated one. Compared with a conventional PID, the controller with ICPSO-PID algorithm has a smaller overshoot, a shorter tuning time and better robustness. The design method proposed in the paper can be applied in a practical electro-hydraulic pitch control system for WTG.

Xu, Chang; Tian, Qiangqiang

2013-01-01

388

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

389

Optimizing wind turbine control system parameters  

Energy Technology Data Exchange (ETDEWEB)

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

Schluter, L.L. [Sandia National Labs., Albuquerque, NM (United States); Vachon, W.A. [Vachon (W.A.) and Associates, Inc., Manchester, MA (United States)

1993-08-01

390

Floating axis wind turbines for offshore power generation—a conceptual study  

International Nuclear Information System (INIS)

The cost of energy produced by offshore wind turbines is considered to be higher than land based ones because of the difficulties in construction, operation and maintenance on offshore sites. To solve the problem, we propose a concept of a wind turbine that is specially designed for an offshore environment. In the proposed concept, a floater of revolutionary shape supports the load of the wind turbine axis. The floater rotates with the turbine and the turbine axis tilts to balance the turbine thrust, buoyancy and gravity. The tilt angle is passively adjustable to wind force. The angle is 30° at rated power. The simplicity of the system leads to further cost reduction of offshore power generation.

2011-10-01

391

Modal testing of a rotating wind turbine  

Energy Technology Data Exchange (ETDEWEB)

A testing technique has been developed to measure the modes of vibration of a rotating vertical-axis wind turbine. This technique has been applied to the Sandia Two-Meter Turbine, where the changes in individual modal frequencies as a function of the rotational speed have been tracked from 0 rpm (parked) to 600 rpm. During rotational testing, the structural response was measured using a combination of strain gages and accelerometers, passing the signals through slip rings. Excitation of the turbine structure was provided by a scheme which suddenly released a pretensioned cable, thus plucking the turbine as it was rotating at a set speed. In addition to calculating the real modes of the parked turbine, the modes of the rotating turbine were also determined at several rotational speeds. The modes of the rotating system proved to be complex due to centrifugal and Coriolis effects. The modal data for the parked turbine were used to update a finite-element model. Also, the measured modal parameters for the rotating turbine were compared to the analytical results, thus verifying the analytical procedures used to incorporate the effects of the rotating coordinate system.

Carne, T.G.; Nord, A.R.

1982-11-01

392

Integrated analysis of wind turbines - The impact of power systems on wind turbine design  

DEFF Research Database (Denmark)

Megawatt-size wind turbines nowadays operate in very complex environmental conditions, and increasingly demanding power system requirements. Pursuing a cost-effective and reliable wind turbine design is a multidisciplinary task. However nowadays, wind turbine design and research areas such as aeroelastic and mechanical, electrical and control, and grid integration, make use of simulation tools dedicated to specific areas. Practical experience shows there is a need to bridge the expertise from different design areas. The focus of this Ph.D. study is on the integrated dynamic analysis of operating conditions that stem from disturbances in the power system. An integrated simulation environment, wind turbine models, and power system models are developed in order to take an integral perspective that considers the most important aeroelastic, structural, electrical, and control dynamics. Applications of the integrated simulation environment are presented. The analysis of an asynchronous machine, and numerical simulations of a fixedspeed wind turbine in the integrated simulation environment, demonstrate the effects on structural loads of including the generator rotor fluxes dynamics in aeroelastic studies. Power system frequency control studies of variable-speed wind turbines with the integrated simulation environment, show that is possible to make a sensible estimation of the contribution of a wind farm to power system frequency control, while studying the impact on wind turbine structural loads. Finally, studies of the impact that voltage faults have on wind turbine loads are presented. The case of unbalanced faults is addressed, the possibilities and drawbacks for reduction of structural loads using electrical control actions is investigated. Load reduction using resonant damping control is proven and quantified.

Barahona GarzĂłn, Braulio

2012-01-01

393

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-05-01

394

Options for wind turbines in the Netherlands  

International Nuclear Information System (INIS)

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

395

Control, stability analysis and grid integration of wind turbines.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In Chapters 2 and 3 of the thesis we propose a self-scheduled control method for a doublyfed induction generator driven by a wind turbine (DFIGWT), whose rotor is connected to the power grid via two back-to-back PWM power converters. We design a controller for this system using the linear matrix inequality based approach to linear parameter varying (LPV) systems, which takes into account the nonlinear dynamics of the system. We propose a two-loop hierarchical control structure....

Wang, Chen

2008-01-01

396

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

397

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

398

Small Wind Turbine Applications: Current Practice in Colorado  

International Nuclear Information System (INIS)

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

399

Dynamic Response Analysis of an Offshore Wind Turbine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The offshore wind power is an attractive renewable energy resource. To improve the wind power generation capacity, there is a strong desire for offshore wind turbine to go to deep waters. For offshore fixed wind turbine, stronger foundation like jacket structure has a good applicability for deeper water depth. A 70-meters jacket substructure for offshore wind turbine is designed. This thesis focuses on the dynamic structural response analysis of this jacket substructure, with a particular foc...

Li, Yu

2011-01-01

400

Low Cost Small Wind Turbine Generators for Developing Countries:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Wind energy accounts for an increasing percentage of the energy supplied to the electricity network. Electricity generation from wind is now cheaper than other renewables and almost cost competitive with other conventional sources of electricity generation. However, this impressive growth is largely due to advances in large wind turbines, particularly off-shore