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1

OPERATIONAL MODAL ANALYSIS AND WAVELET TRANSFORMATION FOR DAMAGE IDENTIFICATION IN WIND TURBINE BLADES  

E-print Network

OPERATIONAL MODAL ANALYSIS AND WAVELET TRANSFORMATION FOR DAMAGE IDENTIFICATION IN WIND TURBINE-frequency modes. KEYWORDS : Wind Turbine Blades, Debonding, Wavelet Transformation, Operational Modal Analysis. INTRODUCTION While failure can happen in any structural component of the wind turbine, one of the most common

Paris-Sud XI, Université de

2

Hilbert Transform-Based Bearing Failure Detection in DFIG-Based Wind Turbines  

E-print Network

and proactive maintenance of wind turbines assumes more importance with the increasing number of installed wind. In this context, cost-effective, predictive and proactive maintenance of wind turbines assumes more importanceHilbert Transform-Based Bearing Failure Detection in DFIG-Based Wind Turbines Yassine Amirat1

Boyer, Edmond

3

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

Microsoft Academic Search

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

Michal Sztykiel

2011-01-01

4

Wind turbine  

DOEpatents

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

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

1982-01-01

5

Wind turbine wake aerodynamics  

Microsoft Academic Search

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

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

2003-01-01

6

Wind Turbine Structural Dynamics  

NASA Technical Reports Server (NTRS)

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

Miller, D. R. (editor)

1978-01-01

7

Wind turbine acoustics  

Microsoft Academic Search

Available information on the physical characteristics of the noise generated by wind turbines is summarized, with example sound pressure time histories, narrow- and broadband frequency spectra, and noise radiation patterns. Reviewed are noise measurement standards, analysis technology, and a method of characterizing wind turbine noise. Prediction methods are given for both low-frequency rotational harmonics and broadband noise components. Also included

Harvey H. Hubbard; Kevin P. Shepherd

1990-01-01

8

Wind turbine acoustics  

NASA Astrophysics Data System (ADS)

Available information on the physical characteristics of the noise generated by wind turbines is summarized, with example sound pressure time histories, narrow- and broadband frequency spectra, and noise radiation patterns. Reviewed are noise measurement standards, analysis technology, and a method of characterizing wind turbine noise. Prediction methods are given for both low-frequency rotational harmonics and broadband noise components. Also included are atmospheric propagation data showing the effects of distance and refraction by wind shear. Human perception thresholds, based on laboratory and field tests, are given. Building vibration analysis methods are summarized. The bibliography of this report lists technical publications on all aspects of wind turbine acoustics.

Hubbard, Harvey H.; Shepherd, Kevin P.

1990-12-01

9

Wind turbine acoustics  

NASA Technical Reports Server (NTRS)

Available information on the physical characteristics of the noise generated by wind turbines is summarized, with example sound pressure time histories, narrow- and broadband frequency spectra, and noise radiation patterns. Reviewed are noise measurement standards, analysis technology, and a method of characterizing wind turbine noise. Prediction methods are given for both low-frequency rotational harmonics and broadband noise components. Also included are atmospheric propagation data showing the effects of distance and refraction by wind shear. Human perception thresholds, based on laboratory and field tests, are given. Building vibration analysis methods are summarized. The bibliography of this report lists technical publications on all aspects of wind turbine acoustics.

Hubbard, Harvey H.; Shepherd, Kevin P.

1990-01-01

10

Wind Turbine Acoustic Noise A white paper  

E-print Network

Wind Turbine Acoustic Noise A white paper Prepared by the Renewable Energy Research Laboratory...................................................................... 8 Sound from Wind Turbines .............................................................................................. 10 Sources of Wind Turbine Sound

Massachusetts at Amherst, University of

11

Wind Turbine Blockset General Overview  

E-print Network

Wind Turbine Blockset in Saber General Overview and Description of the Models Florin Iov, Adrian Turbine Blockset in Saber Abstract. This report presents a new developed Saber Toolbox for wind turbine, optimize and design wind turbines". The report provides a quick overview of the Saber and then explains

12

Floating wind turbine system  

NASA Technical Reports Server (NTRS)

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

Viterna, Larry A. (Inventor)

2009-01-01

13

Wind Turbine Acoustics  

NASA Technical Reports Server (NTRS)

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

14

Optimization of Wind Turbine Operation  

E-print Network

Optimization of Wind Turbine Operation by Use of Spinner Anemometer TF Pedersen, NN Sørensen, L Title: Optimization of Wind Turbine Operation by Use of Spinner Anemometer Department: Wind Energy prototype wind turbine. Statistics of the yaw error showed an average of about 10°. The average flow

15

Model Predictive Control Wind Turbines  

E-print Network

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

16

Predicting Noise From Wind Turbines  

NASA Technical Reports Server (NTRS)

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

Grosveld, Ferdinand W.

1990-01-01

17

Airborne Wind Turbine  

SciTech Connect

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

None

2010-09-01

18

Tornado type wind turbines  

SciTech Connect

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

19

Wind turbine acoustic standards  

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

20

Wind turbine dynamics  

NASA Technical Reports Server (NTRS)

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

Thresher, R. W. (editor)

1981-01-01

21

Superconducting wind turbine generators  

NASA Astrophysics Data System (ADS)

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

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

2010-03-01

22

Vertical axis wind turbine development  

Microsoft Academic Search

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

R. E. Walters; J. B. Fanucci; P. W. Hill; P. G. Migliore

1979-01-01

23

Wind tunnel investigation on wind turbine wakes and wind farms  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

24

Modal analysis of wind turbine tower  

Microsoft Academic Search

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

Jie Chen; Dongxiang Jiang

2010-01-01

25

5th International Meeting Wind Turbine Noise  

E-print Network

1 5th International Meeting on Wind Turbine Noise Denver 28 ­ 30 August 2013 Wind Turbine Noise Broadband noise generated aerodynamically is the dominant noise source for a modern wind turbine(Brooks et, clean energy. While profiting from wind energy, the noise produced by a modern wind turbine becomes

Paris-Sud XI, Université de

26

Estimation of Wind Speed in Connection to a Wind Turbine  

E-print Network

Estimation of Wind Speed in Connection to a Wind Turbine X. Ma #3; , N. K. Poulsen #3; , H. Bindner y December 20, 1995 Abstract The wind speed varies over the rotor plane of wind turbine making the wind speed on the rotor plane will be estimated by using a wind turbine as a wind measuring device

27

A Review of Modern Wind Turbine Technology  

Microsoft Academic Search

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

M. Balat

2009-01-01

28

Small wind turbine power curve comparison  

Microsoft Academic Search

This paper focus is on the small wind turbines resource potential estimation. Assessment is done for seven selected small wind turbines and one measured set of wind speed data with the micropower optimization modeling tool HOMER. Goal was to investigate how estimated energy production and economical parameters are sensitive to the selection of small wind turbine. Selected turbines have similar

Z. Simic; M. B. Vrhovcak; D. Sljivac

2009-01-01

29

Towers for Offshore Wind Turbines  

Microsoft Academic Search

Increasing energy demand coupled with pollution free production of energy has found a viable solution in wind energy. Land based windmills have been utilized for power generation for more than two thousand years. In modern times wind generated power has become popular in many countries. Offshore wind turbines are being used in a number of countries to tap the energy

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

2010-01-01

30

Performance of propeller wind turbines  

Microsoft Academic Search

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

A. Wortman

1983-01-01

31

Parametric design of floating wind turbines  

E-print Network

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

Tracy, Christopher (Christopher Henry)

2007-01-01

32

Airfoils for wind turbine  

SciTech Connect

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

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

2000-05-30

33

MEASURING IMPACTS TO BIRDS CAUSED BY WIND TURBINES MEASURING IMPACTS TO BIRDS CAUSED BY WIND TURBINES  

E-print Network

APPENDIX A MEASURING IMPACTS TO BIRDS CAUSED BY WIND TURBINES #12;A-1 APPENDIX A MEASURING IMPACTS TO BIRDS CAUSED BY WIND TURBINES 1.0 INTRODUCTION Differential composition of wind turbines at wind energy used is the number of fatalities per wind turbine per year (Anderson et al. 1999). This metric has

34

Sandia Wind Turbine Loads Database  

DOE Data Explorer

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

35

Dynamics and stability of wind turbine generators  

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

36

Wind Turbines Electrical and Mechanical Engineering  

E-print Network

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

Provancher, William

37

A Fatigue Approach to Wind Turbine Control  

E-print Network

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

38

Fast Wind Turbine Design via Geometric Programming  

E-print Network

Fast Wind Turbine Design via Geometric Programming Warren Hoburg and Pieter Abbeel UC Berkeley the application of GP to large wind turbine design problems a promising approach. Nomenclature (·)a, (·)t axial According to the World Wind Energy Association, wind turbine installations supply approximately 3

Abbeel, Pieter

39

Wind turbines and human health.  

PubMed

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

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

2014-01-01

40

Economic feasibility of wind farm using low wind speed turbine  

Microsoft Academic Search

One of the renewable energy technologies is the wind power technology abundantly used in countries located at high wind speeds. However, most rural areas of developing countries have low wind speeds. Moreover, low wind speed turbine (LWST) has been developed to reduce cost which is currently higher than high wind speed turbine (HWST). Therefore, economic feasibility of wind farm using

U. Sangpanich; G. A. Ault; K. L. Lo

2009-01-01

41

Offshore Wind Turbines: Some Technical Challenges  

E-print Network

1 Offshore Wind Turbines: Some Technical Challenges Prof. Guy Houlsby FREng Oxford University House engineers concerned with installation of offshore wind turbines. The author is Professor of Civil solved, a DTI and EPSRC-sponsored research programme on foundations for wind turbines will be briefly

Houlsby, Guy T.

42

Dynamics and Stability of Wind Turbine Generators  

Microsoft Academic Search

This paper describes the dynamic and stability properties of wind turbine generators connected to power systems. Both synchronous and induction generators are considered. A comparison is made between wind turbines, steam, and hydro units. The unusual phenomena associated with wind turbines are emphasized. The general control requirements are discussed, as well as various schemes for torsional damping such as speed

E. N. Hinrichsen; P. J. Nolan

1982-01-01

43

Wind Turbine Blockset in Matlab/Simulink  

E-print Network

Wind Turbine Blockset in Matlab/Simulink General Overview and Description of the Models Florin Iov, Anca Daniela Hansen, Poul Sørensen, Frede Blaabjerg Aalborg University March 2004 #12;22 Wind Turbine to model, optimize and design wind turbines" and it has been used as a general developer tool for other

44

Computational Analysis of Shrouded Wind Turbine Configurations  

E-print Network

Computational Analysis of Shrouded Wind Turbine Configurations Aniket C. Aranake Vinod K-dimensional simulations of shrouded wind turbines are performed for selected shroud geometries. The results are compared at the highest wind speed for which the flow over the bare turbine blade stays attached. Flow fields are examined

Alonso, Juan J.

45

The Overvoltage protection Of wind turbine generators  

Microsoft Academic Search

The paper introduces the related characteristics of wind turbine generators, Such as the wind turbine generator may cause serious over-voltage problems of electromagnetic compatibility for using converter technique and be struck by lightning easily and also result in high maintenance costs. So we analyze several hotspots of the over-voltage protection of wind turbine generators, such as the standard on the

Tianwen Yin; Niansheng Xu; Rongxing Jiang

2009-01-01

46

Installing Small Wind Turbines Seminar and Workshop  

E-print Network

on the issues of installation and maintenance of SWTs. The workshop will be led by two wind turbine engineersSeminar and Workshop Installing Small Wind Turbines Seminar and Workshop Location: Murdoch January 2011 Details for Registration and Payment: Mr Daniel Jones, National Small Wind Turbine Test

47

Small Wind Turbine Testing and Applications Development  

Microsoft Academic Search

Small wind turbines offer a promising alternative for many remote electrical uses where there is a good wind resource. The National Wind Technology Center (NWTC) of the National Renewable Energy Laboratory helps further the role that small turbines can play in supplying remote power needs. The NWTC tests and develops new applications for small turbines. The NWTC also develops components

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

1999-01-01

48

Wind turbines in simulated gusts  

Microsoft Academic Search

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

C. Egozcue; R. Leblanc; R. Goethals

1982-01-01

49

Economics of Small Wind Turbines  

NSDL National Science Digital Library

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

2012-10-02

50

Wind turbine testing. Final report  

SciTech Connect

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

Smith, P.R.

1995-01-01

51

Preview Control for Wind Turbines  

NASA Astrophysics Data System (ADS)

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

Ozdemir, Ahmet Arda

52

Small Wind Turbine Testing and Applications Development  

SciTech Connect

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

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

1999-09-14

53

Progress in Wind-Wheel Turbines  

NASA Technical Reports Server (NTRS)

New wind turbine offers important advantages over conventional propeller wind turbines according to theoretical studies and tests of small working models. Project results are described in final report now available. Windwheel turbines consists of bladed wheel, main housing, two forward ducts (front concentrators), two side ducts (side concentrators) and base to support and elevate housing.

Frost, W.; Kessel, P. A.

1983-01-01

54

Design optimization of small wind turbines for low wind regimes  

Microsoft Academic Search

Attention is given to two examples illustrating the design optimization process for small wind turbines, which is concerned with machine parameters and the wind characteristics and electrical loads of the intended operating environment. The optimization process emphasizes the importance of rated wind speed, rotor rpm, generator size, and rotor blade characteristics. Wind turbines are noted to have been designed for

D. E. Cromack; Debbie Oscar

1984-01-01

55

A Direct Drive Wind Turbine HTS Generator  

Microsoft Academic Search

The wind turbine market is growing rapidly, and there has also been a trend toward ever increasing turbine rating. Most turbines to date has used geared high speed generators, but a history of gearbox reliability problems have turned many turbine manufacturers towards direct drive generators, which are very low speed, high torque, and therefore very large. Superconducting machines offer the

Clive Lewis; Jens Müller

2007-01-01

56

Wind Turbine Manufacturing Process Monitoring  

SciTech Connect

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

57

Frequency control and wind turbine technologies  

Microsoft Academic Search

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

Gillian Lalor; Alan Mullane; Mark O'Malley

2005-01-01

58

Wind turbine operation and maintenance experience  

Microsoft Academic Search

Operational information was collected and evaluated from five sites covering four different wind turbine types. The results are presented for the current experience, and projections are developed for future large wind power generation stations. Although preliminary because of the small data base, several important trends are apparent. The wind turbines with ratings near 50 kW are achieving higher availabilities than

1985-01-01

59

Development of High-Performance Wind Turbine with Brimmed Diffuser  

Microsoft Academic Search

We have developed a new wind turbine system that consists of a diffuser with a broad-ring brim at the exit periphery and a conventional wind turbine inside it. The new wind turbine has demonstrated power augmentation for a given turbine diameter and wind speed by a factor of about 2 3 compared with a bare wind turbine. This is because

Yuji Ohya; Takashi Karasudani; Akira Sakurai

2003-01-01

60

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

Microsoft Academic Search

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

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

2006-01-01

61

Wind turbines in simulated gusts  

NASA Astrophysics Data System (ADS)

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.

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

1982-11-01

62

Small Wind Research Turbine: Final Report  

SciTech Connect

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

63

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

SciTech Connect

This report summarizes the results of a safety and function test that NREL conducted on the Ventera VT10 wind turbine. This test was conducted in accordance with the International Electrotechnical Commissions' (IEC) standard, Wind Turbine Generator System Part 2: Design requirements for small wind turbines, IEC 61400-2 Ed.2.0, 2006-03.

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

2012-11-01

64

Lightning protection of wind turbines  

NASA Technical Reports Server (NTRS)

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

Dodd, C. W.

1982-01-01

65

Installation and initial operation of a 4100 watt wind turbine  

NASA Technical Reports Server (NTRS)

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

66

Wind turbine optimal control during storms  

NASA Astrophysics Data System (ADS)

This paper proposes a control algorithm that enables wind turbine operation in high winds. With this objective, an online optimization procedure is formulated that, based on the wind turbine state, estimates those extremal wind speed variations that would produce maximal allowable wind turbine loads. Optimization results are compared to the actual wind speed and, if there is a danger of excessive loading, the wind turbine power reference is adjusted to ensure that loads stay within allowed limits. This way, the machine can operate safely even above the cut-out wind speed, thereby realizing a soft envelope-protecting cut-out. The proposed control strategy is tested and verified using a high-fidelity aeroservoelastic simulation model.

Petrovi?, V.; Bottasso, C. L.

2014-06-01

67

Collected Papers on Wind Turbine Technology  

NASA Technical Reports Server (NTRS)

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

Spera, David A. (editor)

1995-01-01

68

Diffuser Augmented Wind Turbine Analysis Code  

E-print Network

Wind Energy is becoming a significant source of energy throughout the world. This ever increasing field will potentially reach the limit of availability and practicality with the wind farm sites and size of the turbine itself. Therefore...

Carroll, Jonathan

2014-05-31

69

Investigation on installation of offshore wind turbines  

NASA Astrophysics Data System (ADS)

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

Wang, Wei; Bai, Yong

2010-06-01

70

Washington University Can the Sound Generated by Modern Wind Turbines  

E-print Network

Windmills:Sound from Windmills: Wind Turbine SyndromeWind Turbine Syndrome Dr. Nina Pierpont, MD, 2009 (selfWashington University Can the Sound Generated by Modern Wind Turbines Affect the Health of Those turbines haveWind turbines have been getting biggerbeen getting bigger and bigger....and bigger.... Lars

Salt, Alec N.

71

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

SciTech Connect

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

None

2010-02-22

72

Microprocessor control of a wind turbine generator  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

73

Dual-speed wind turbine generation  

Microsoft Academic Search

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

E. Muljadi; C. P. Butterfield; D. Handman

1996-01-01

74

Computational Aerodynamics and Aeroacoustics for Wind Turbines  

E-print Network

objective of the research was to develop new computational tools or approaching techniques for analysingComputational Aerodynamics and Aeroacoustics for Wind Turbines #12;#12;Computational Aerodynamics Shen, Wen Zhong Computational Aerodynamics and Aeroacoustics for Wind Turbines Doctor Thesis Technical

75

Plasma Enhanced Aerodynamics of Wind Turbine Blades  

Microsoft Academic Search

A series of computer simulations was conducted to determine the optimal method for reducing the chord length of large wind turbine blades while incorporating advanced flow control to offset the resulting loss in aerodynamic performance. The dominant building trend in the wind energy industry of turbines with progressively larger diameters provided the inspiration for this study. By reducing the chord

John Cooney; Thomas Corke; Robert Nelson

2009-01-01

76

Simulation investigation of wind turbine imbalance faults  

Microsoft Academic Search

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

Xiang Gong; Wei Qiao

2010-01-01

77

Large-scale wind turbine structures  

Microsoft Academic Search

The purpose of this presentation is to show how structural technology was applied in the design of modern wind turbines, which were recently brought to an advanced stage of development as sources of renewable power. Wind turbine structures present many difficult problems because they are relatively slender and flexible; subject to vibration and aeroelastic instabilities; acted upon by loads which

David A. Spera

1988-01-01

78

Towards the Zero Maintenance Wind Turbine  

Microsoft Academic Search

Renewable sources are set to form an increasingly important component of electricity generation in the UK and worldwide. Wind turbines are the most developed renewable technology and are now the largest renewable source for electricity in the UK. Most new turbines are currently being sited onshore but offshore sites could harness greater resource with higher wind speeds and lower turbulence.

M. Wilkinson; F. Spianto; M. Knowles

2006-01-01

79

An Isolated Small Wind Turbine Emulator  

Microsoft Academic Search

An isolated small wind turbine emulator is described in this paper. The system consists of a PC controlled variable speed DC motor coupled to a synchronous generator. Dump load is connected to the generator through a microcontroller controlled DC-DC converter. The varying aerodynamic torque of the wind turbine due to furling action and its resulting dynamics are incorporated in the

M. Tariq Iqbal; John E. Quaicoe

2006-01-01

80

Design of dynamic simulation of wind turbine  

Microsoft Academic Search

As one kind of regenerative energy, as well as a part of smart grid, wind power has become a hot topic in many countries all over the world. Due to lack of wind farm circumstance, it is difficult to carry out an actual experiment on wind turbine in the laboratory. It is necessary to build a simulative system of wind

Zhang Lei; Daozhuo Jiang; Zhang Zhenhua; Yan Bo

2010-01-01

81

Responses of floating wind turbines to wind and wave excitation  

E-print Network

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

Lee, Kwang Hyun

2005-01-01

82

Siting guidelines for utility application of wind turbines. Final report  

Microsoft Academic Search

Utility-oriented guidelines are described for identifying viable sites for wind turbines. Topics and procedures are also discussed that are important in carrying out a wind turbine siting program. These topics include: a description of the Department of Energy wind resource atlases; procedures for predicting wind turbine performance at potential sites; methods for analyzing wind turbine economics; procedures for estimating installation

Pennell

1983-01-01

83

Economic Analysis of the Stability in the Wind Turbine Selection  

Microsoft Academic Search

Selection of wind turbine is one of the main factors which affect the economics of wind power projects. The current domestic economic analysis of wind turbine selection are relatively backward and the evaluation indexes are imperfect- -major concerned indicators are theoretic indicators such as characteristics of wind turbine and rated generating capacity, lacking of the assessment of actual wind turbine

Zeng Ming; A. Sikaer; Geng Weiting; Li Chen

2010-01-01

84

Siting guidelines for utility application of wind turbines  

Microsoft Academic Search

Utility oriented guidelines are described for identifying viable sites for wind turbines. Topics and procedures are also discussed that are important in carrying out a wind turbine siting program. These topics include: a description of the Department of Energy wind resource atlases; procedures for predicting wind turbine performance at potential sites; methods for analyzing wind turbine economics; procedures for estimating

W. T. Pennell

1983-01-01

85

MOD-2 wind turbine farm stability study  

NASA Technical Reports Server (NTRS)

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

Hinrichsen, E. N.

1980-01-01

86

A Stochastic DEVS Wind Turbine Component Model for Wind Farm Simulation  

E-print Network

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

Ding, Yu

87

Smart structure for small wind turbine blade  

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

88

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

E-print Network

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

Leu, Tzong-Shyng "Jeremy"

89

Proceedings of the 2008 International Conference on Electrical Machines Paper ID 1434 DFIG-Based Wind Turbine Fault Diagnosis  

E-print Network

-Based Wind Turbine Fault Diagnosis Using a Specific Discrete Wavelet Transform E. Al-Ahmar1,2 , M for electrical and mechanical fault diagnosis in a DFIG-based wind turbine. The investigated technique unambiguously diagnose faults under transient conditions. Index Terms--Wind turbine, Doubly-Fed Induction

Boyer, Edmond

90

Industrial drive based wind simulator for small wind turbine optimisation  

Microsoft Academic Search

As part of the research effort to optimise a small grid-connected wind turbine, a wind simulator was built. The simulator enables the researcher to simulate any given wind speed as well as a predefined or recorded wind profile. The control variable for the simulation is torque, since the blades in a real situation produce a certain torque on the generator

S. Paepen; K. De Koker; P. Adams; P. Coussens

2011-01-01

91

Design criteria for small wind turbines. Part 2: Wind characterizing  

Microsoft Academic Search

A calculation model to determine turbulent wind velocity and Wind Direction Fluctuations (WDFs) on a rotating wind turbine rotor was developed to draw up simply applicable and rotor type differentiated design criteria. Using statistical methods, fatiguing and extreme wind gusts as well as turbulent WDFs were constructed and determined as dependent upon criteria chosen (exceed chances). Interstationary (mesoscale) WDFs expected

G. L. H. Beugeling; P. E. J. Vermeulen

1985-01-01

92

Aerodynamic response analysis of wind turbines  

Microsoft Academic Search

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

Jing Li; Jianyun Chen; Xiaobo Chen

2011-01-01

93

Wind turbine simulator based on DSEM  

Microsoft Academic Search

In this paper, a new type of wind turbine simulator (WTS) based on DSEM (doubly salient electro-magnetic machine) is proposed to simulate the steady-state and dynamic characteristics of a wind turbine in direct-driven DSEG (doubly salient electromagnetic generator) wind power generation system. A simple and effective torque control strategy is proposed to realize torque closed-loop control of DSEM which reproduces

Cheng Fangshun; Zhou Bo; Zhang Le

2009-01-01

94

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

E-print Network

ABSTRACT Structural responses and power output of a wind turbine are strongly affected by the wind field acting on the wind turbine. Knowledge about the wind field and its variations is essential not only for designing, but also for cost-efficiently managing wind turbines. Wind field monitoring

Stanford University

95

Numerical investigation of wind turbine and wind farm aerodynamics  

NASA Astrophysics Data System (ADS)

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

Selvaraj, Suganthi

96

Ris-R-1400(EN) Dynamic wind turbine models in power  

E-print Network

Risø-R-1400(EN) Dynamic wind turbine models in power system simulation tool DIgSILENT Anca D December 2003 #12;#12;Contents Preface 5 1 Introduction 6 2 Wind turbine modelling in DIgSILENT 7 2.1 Power converters 14 2.2.3 Transformer 16 2.3 DSL models of wind turbine in DIgSILENT 18 2.3.1 Initialisation issues

97

Effect of precipitation on wind turbine performance  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

98

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

Microsoft Academic Search

Wind turbine system reliability is a critical factor in the success of a wind energy project. Poor reliability directly affects both the project's revenue stream through increased operation and maintenance (O&M) costs and reduced availability to generate power due to turbine downtime. Indirectly, the acceptance of wind-generated power by the financial and developer communities as a viable enterprise is influenced

Walford; Christopher A

2006-01-01

99

Wind Turbines and Health A Rapid Review of the Evidence  

E-print Network

1 Wind Turbines and Health A Rapid Review of the Evidence July 2010 #12;2 Wind Turbines and Health of the evidence from current literature on the issue of wind turbines and potential impacts on human health regarding wind turbines and their potential effect on human health. It is important to note that these views

Firestone, Jeremy

100

A stochastic DEVS wind turbine component model for wind farm simulation  

Microsoft Academic Search

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

Eduardo Pérez; Lewis Ntaimo; Eunshin Byon; Yu Ding

2010-01-01

101

Composite Materials for Wind Power Turbine Blades  

Microsoft Academic Search

Renewable energy resources, of which wind energy is prominent, are part of the solution to the global energy problem. Wind turbine and the rotorblade concepts are reviewed, and loadings by wind and gravity as important factors for the fatigue performance of the materials are considered. Wood and composites are discussed as candidates for rotorblades. The fibers and matrices for composites

Povl Brøndsted; Hans Lilholt; Aage Lystrup

2005-01-01

102

Stability Simulation of Wind Turbine Systems  

Microsoft Academic Search

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

P. M. Anderson; Anjan Bose

1983-01-01

103

PowerJet Wind Turbine Project  

SciTech Connect

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

Bartlett, Raymond J

2008-11-30

104

Wind turbine condition monitoring and fault diagnosis using both mechanical and electrical signatures  

Microsoft Academic Search

Some large wind turbines use a synchronous generator, directly-coupled to the turbine, and a fully rated converter to transform power from the turbine to the mains. This paper considers condition monitoring and diagnosis of mechanical and electrical faults in such a variable speed machine. A new condition monitoring technique is proposed in this paper, which removes the negative influence of

Wenxian Yang; P. J. Tavner; Michael Wilkinson

2008-01-01

105

WIND TURBINE SITING IN AN URBAN ENVIRONMENT: THE HULL, MA 660 KW TURBINE  

E-print Network

1 WIND TURBINE SITING IN AN URBAN ENVIRONMENT: THE HULL, MA 660 KW TURBINE J. F. Manwell, J. G. Mc turbine at Windmill Point in Hull, Massachusetts represents a high point in the long history of wind's performance of the wind turbine is given. The paper also presents an overview of possible future wind

Massachusetts at Amherst, University of

106

Portable wind turbine for charging batteries  

SciTech Connect

In a wind turbine assembly incorporating a diffuser, the diffuser includes an articulated duct formed of a set of members, such as the sectors of a conic section, which are pivotable about axes in a plane normal to the turbine axis. To permit an enlargement or contraction of the articulated duct, the members are joined by flexible gussets or, alternatively, are configured for overlapping. Springs offset from the pivoting axes are attached to the members to provide a bistable attitude thereto. In response to high winds, the spring forces are overcome by the wind forces on the articulated duct to allow the members to pivot inwardly reducing the effective wind capture area of the diffuser. The diffuser is further fabricated with slots between sections of duct to enlarge the effective area swept by the turbine blades for increased power availability from the turbine.

Oman, R.A.

1982-04-13

107

Flexible dynamics of floating wind turbines  

E-print Network

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

Luypaert, Thomas (Thomas J.)

2012-01-01

108

Wind Turbine Drivetrain Condition Monitoring - An Overview  

SciTech Connect

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

109

Diffuser for augmenting a wind turbine  

DOEpatents

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

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

1984-01-01

110

Danehy Park Wind Turbine Project Preliminary Assessment Report  

E-print Network

Danehy Park Wind Turbine Project Preliminary Assessment Report Danehy Park Project Group Wind/s) 13 10 14.5 ~15 12 Table 1: Summary of basic wind turbine specifications for turbines in evaluation. Bob Paine and Scott Abbett for their thoughts and experiences with the Medford McGlynn School wind

111

Riso-M-2546 g Wind Turbine Test  

E-print Network

Riso-M-2546 g Wind Turbine Test Wind Matic WM 17S Troels Friis Pedersen The Test Station for Windmills Riso National Laboratory, DK-4000 Roskilde Denmark April 1986 #12;#12;RIS0-M-2546 WIND TURBINE describes standard measurements performed on a Wind-Matic WM 17S, 75 kW wind turbine. The measurements

112

Wave Models for Offshore Wind Turbines  

Microsoft Academic Search

In the design of wind turbines—onshore or offshore—the prediction of extreme loads as- sociated with a target (long) return period requires statistical extrapolation from available loads data. The data required for such extrapolation are obtained by stochastic time- domain simulation of the inflow turbulence and of the turbine response. Prediction of accurate loads depends on assumptions made in the simulation

Puneet Agarwal; Lance Manuely

2008-01-01

113

A fatigue approach to wind turbine control  

Microsoft Academic Search

Conventional design of wind turbine controllers is focused on speed and produced electric power. As fatigue loads is an important design consideration, the resulting design is evaluated also with respect to the fatigue loads inflicted on the turbine structure. This is normally done by performing simulations using tools like FLEX, HAWC or FAST, followed by rainflow counting in the resulting

K Hammerum; P Brath; N K Poulsen

2007-01-01

114

Wind turbine value analysis for electric utilities  

NASA Astrophysics Data System (ADS)

A methodology for the analysis of the value of large-scale wind turbines to electric utilities, and its application to utility, socioeconomic and meteorological data in two case studies is described. The value analysis was carried out for the year of reference 1985 and included different levels of wind turbine penetration. Results of the value analysis are given. The utility planning procedures in current use and the unique problems of the integration of wind power into the power system are discussed. Observations and conclusions regarding the current and future potential of wind power for utilities are presented.

Dub, W.

1982-06-01

115

Behavior of bats at wind turbines  

USGS Publications Warehouse

Wind turbines are causing unprecedented numbers of bat fatalities. Many fatalities involve tree-roosting bats, but reasons for this higher susceptibility remain unknown. To better understand behaviors associated with risk, we monitored bats at three experimentally manipulated wind turbines in Indiana, United States, from July 29 to October 1, 2012, using thermal cameras and other methods. We observed bats on 993 occasions and saw many behaviors, including close approaches, flight loops and dives, hovering, and chases. Most bats altered course toward turbines during observation. Based on these new observations, we tested the hypotheses that wind speed and blade rotation speed influenced the way that bats interacted with turbines. We found that bats were detected more frequently at lower wind speeds and typically approached turbines on the leeward (downwind) side. The proportion of leeward approaches increased with wind speed when blades were prevented from turning, yet decreased when blades could turn. Bats were observed more frequently at turbines on moonlit nights. Taken together, these observations suggest that bats may orient toward turbines by sensing air currents and using vision, and that air turbulence caused by fast-moving blades creates conditions that are less attractive to bats passing in close proximity. Tree bats may respond to streams of air flowing downwind from trees at night while searching for roosts, conspecifics, and nocturnal insect prey that could accumulate in such flows. Fatalities of tree bats at turbines may be the consequence of behaviors that evolved to provide selective advantages when elicited by tall trees, but are now maladaptive when elicited by wind turbines.

Cryan, Paul; Gorresen, Marcos; Hine, Cris D.; Schirmacher, Michael; Diehl, Robert H.; Huso, Manuela M.; Hayman, David T.S.; Fricker, Paul D.; Bonaccorso, Frank J.; Johnson, Douglas H.; Heist, Kevin; Dalton, David C.

2014-01-01

116

Behavior of bats at wind turbines.  

PubMed

Wind turbines are causing unprecedented numbers of bat fatalities. Many fatalities involve tree-roosting bats, but reasons for this higher susceptibility remain unknown. To better understand behaviors associated with risk, we monitored bats at three experimentally manipulated wind turbines in Indiana, United States, from July 29 to October 1, 2012, using thermal cameras and other methods. We observed bats on 993 occasions and saw many behaviors, including close approaches, flight loops and dives, hovering, and chases. Most bats altered course toward turbines during observation. Based on these new observations, we tested the hypotheses that wind speed and blade rotation speed influenced the way that bats interacted with turbines. We found that bats were detected more frequently at lower wind speeds and typically approached turbines on the leeward (downwind) side. The proportion of leeward approaches increased with wind speed when blades were prevented from turning, yet decreased when blades could turn. Bats were observed more frequently at turbines on moonlit nights. Taken together, these observations suggest that bats may orient toward turbines by sensing air currents and using vision, and that air turbulence caused by fast-moving blades creates conditions that are less attractive to bats passing in close proximity. Tree bats may respond to streams of air flowing downwind from trees at night while searching for roosts, conspecifics, and nocturnal insect prey that could accumulate in such flows. Fatalities of tree bats at turbines may be the consequence of behaviors that evolved to provide selective advantages when elicited by tall trees, but are now maladaptive when elicited by wind turbines. PMID:25267628

Cryan, Paul M; Gorresen, P Marcos; Hein, Cris D; Schirmacher, Michael R; Diehl, Robert H; Huso, Manuela M; Hayman, David T S; Fricker, Paul D; Bonaccorso, Frank J; Johnson, Douglas H; Heist, Kevin; Dalton, David C

2014-10-21

117

Behavior of bats at wind turbines  

PubMed Central

Wind turbines are causing unprecedented numbers of bat fatalities. Many fatalities involve tree-roosting bats, but reasons for this higher susceptibility remain unknown. To better understand behaviors associated with risk, we monitored bats at three experimentally manipulated wind turbines in Indiana, United States, from July 29 to October 1, 2012, using thermal cameras and other methods. We observed bats on 993 occasions and saw many behaviors, including close approaches, flight loops and dives, hovering, and chases. Most bats altered course toward turbines during observation. Based on these new observations, we tested the hypotheses that wind speed and blade rotation speed influenced the way that bats interacted with turbines. We found that bats were detected more frequently at lower wind speeds and typically approached turbines on the leeward (downwind) side. The proportion of leeward approaches increased with wind speed when blades were prevented from turning, yet decreased when blades could turn. Bats were observed more frequently at turbines on moonlit nights. Taken together, these observations suggest that bats may orient toward turbines by sensing air currents and using vision, and that air turbulence caused by fast-moving blades creates conditions that are less attractive to bats passing in close proximity. Tree bats may respond to streams of air flowing downwind from trees at night while searching for roosts, conspecifics, and nocturnal insect prey that could accumulate in such flows. Fatalities of tree bats at turbines may be the consequence of behaviors that evolved to provide selective advantages when elicited by tall trees, but are now maladaptive when elicited by wind turbines. PMID:25267628

Cryan, Paul. M.; Gorresen, P. Marcos; Hein, Cris D.; Schirmacher, Michael R.; Diehl, Robert H.; Huso, Manuela M.; Hayman, David T. S.; Fricker, Paul D.; Bonaccorso, Frank J.; Johnson, Douglas H.; Heist, Kevin; Dalton, David C.

2014-01-01

118

Optimizing small wind turbine performance in battery charging applications  

Microsoft Academic Search

Many small wind turbine generators (10 kW or less) consist of a variable speed rotor driving a permanent magnet synchronous generator (alternator). One application of such wind turbines is battery charging, in which the generator is connected through a rectifier to a battery bank. The wind turbine electrical interface is essentially the same whether the turbine is part of a

Stephen Drouilhet; Eduard Muljadi; Richard Holz; Vahan Gevorgian

1995-01-01

119

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

E-print Network

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

Chiao, Jung-Chih

120

Infrasound emission generated by wind turbines  

NASA Astrophysics Data System (ADS)

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

Ceranna, Lars; Pilger, Christoph

2014-05-01

121

Jet spoiler arrangement for wind turbine  

DOEpatents

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

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

1983-09-15

122

Jet spoiler arrangement for wind turbine  

DOEpatents

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

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

1985-01-01

123

Abstract--This paper proposes a methodology to decide the optimal matching between the size of the rotor of a wind turbine  

E-print Network

of the rotor of a wind turbine and the rated power of a permanent magnet synchronous machine. This is made of the wind turbine, the gearbox's transformation ratio, the battery voltage and the wind speed probability's rated power and the wind turbine's rotor size. The system studied in this paper consists of 220 (V)/50

Paris-Sud XI, Université de

124

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

Microsoft Academic Search

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

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

1978-01-01

125

Multilevel converters for 10 MW Wind Turbines  

Microsoft Academic Search

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

Ke Ma; Frede Blaabjerg

2011-01-01

126

Radar signature control of wind turbine generators  

Microsoft Academic Search

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

A. Tennant; B. Chambers

2005-01-01

127

Practical aspects for small wind turbine applications  

Microsoft Academic Search

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

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

128

A review of large wind turbine systems  

Microsoft Academic Search

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

H. Selzer; J. I. Lerner

1983-01-01

129

ACOUSTIC TESTS OF SMALL WIND TURBINES  

Microsoft Academic Search

Eight small wind turbines ranging from 400 watts to 100 kW in rated power were tested for acoustic emis- sions at the U.S. Department of Energy's National Re- newable Energy Laboratory. Rigorous test procedures based on international standards were followed for measurements and data analyses. Results are presented in the form of sound pressure level versus wind speed, where the

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

130

Field verification program for small wind turbines  

SciTech Connect

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

Windward Engineering, LLC

2003-11-30

131

Condition Monitoring of Wind Turbines: A Review  

E-print Network

ABSTRACT- This paper presents condition monitoring in wind turbines, and related technologies currently applied in practice and under development for aerospace applications, are reviewed. Condition monitoring system estimate the current condition of a machine from sensor measurements, whereas prediction systems give a probabilistic forecast of the future condition of the machine under the projected usage conditions. Current condition monitoring practice in wind turbine rotors involves tracking rotor imbalance, aerodynamic, surface roughness and overall performance and offline and online measurements of stress and strain. Key words- Wind energy, Condition monitoring 1.

Sachin Sharma; Dalgobind Mahto

132

Large, low cost composite wind turbine blades  

NASA Technical Reports Server (NTRS)

A woven roving E-glass tape, having all of its structural fibers oriented across the tape width was used in the manufacture of the spar for a wind turbine blade. Tests of a 150 ft composite blade show that the transverse filament tape is capable of meeting structural design requirements for wind turbine blades. Composite blades can be designed for interchangeability with steel blades in the MOD-1 wind generator system. The design, analysis, fabrication, and testing of the 150 ft blade are discussed.

Gewehr, H. W.

1979-01-01

133

Large horizontal axis wind turbine development  

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

134

Large Horizontal-Axis Wind Turbines  

NASA Technical Reports Server (NTRS)

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

Thresher, R. W. (editor)

1982-01-01

135

LES of wind turbine wakes: Evaluation of turbine parameterizations  

NASA Astrophysics Data System (ADS)

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

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

2009-11-01

136

Wind Turbine Micropitting Workshop: A Recap  

SciTech Connect

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

137

Load attenuating passively adaptive wind turbine blade  

DOEpatents

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

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

2003-01-01

138

Ris-PhD-Report Wind Turbines: Unsteady Aerodynamics and  

E-print Network

Risø-PhD-Report Wind Turbines: Unsteady Aerodynamics and Inflow Noise Brian Riget Broe Risø-PhD-47 Title: Wind Turbines: Unsteady Aerodynamics and Inflow Noise Division: Wind Energy Division Risø-PhD-47(EN) December 2009 Abstract (max. 2000 char.): Aerodynamical noise from wind turbines due

139

Voltage grid support of DFIG wind turbines during grid faults  

Microsoft Academic Search

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

Anca D. Hansen; Gabriele Michalke

140

Cambridge Danehy Park Wind Turbine Preliminary Project Assessment  

E-print Network

Cambridge Danehy Park Wind Turbine Preliminary Project Assessment Overview MIT Wind Energy Projects 4 / 25 2.5 / 25 Rated Wind Speed (m/s) 13 10 14.5 ~15 12 The above turbines were chosen to provide, several recent studies examining birds and wind turbines have observed that most birds usually avoid

141

Wind Turbine Pitch Angle Controllers for Grid Frequency Stabilisation  

E-print Network

Wind Turbine Pitch Angle Controllers for Grid Frequency Stabilisation Clemens Jauch Risø National: In this paper it is investigated how active-stall wind turbines can contribute to the stabilisation of the power. Introduction As wind power penetration reaches considerable levels, power system operators demand wind turbines

142

Wind Turbine Test \\^ind Matic WM 15S  

E-print Network

00 ·2 V. v/ RisoM-2481 Wind Turbine Test \\^ind Matic WM 15S Troels Friis Pedersent The Test Station for Windmills Riso National Laboratory, DK-4000 Roskilde, Denmark July 1986 #12;#12;RIS0-M-2481 WIND TURBINE describes standard measurements performed on a Wind-Matic WM 15S, 55 kW wind turbine. The measurements

143

Ris-R-1330(EN) Wind Turbine Power Performance  

E-print Network

Risø-R-1330(EN) Wind Turbine Power Performance Verification in Complex Terrain and Wind Farms/EN 61400-12 Ed 1 standard for wind turbine power performance testing is being revised. The standard on power performance measurements on individual wind turbines. The second one is a power performance

144

Integrated monitoring of offshore wind turbines – requirements, concepts and experiences  

Microsoft Academic Search

Wind turbines on offshore sites (OWECs) are subjected to combined loads from wind and waves. These dynamic loads, with a frequency content within the range of the natural frequencies of the structures, cause fatigue-effective stresses in the substructures of wind turbines. Therefore, the examination of natural frequencies is an important part within the design process of wind turbines. The quality

Rolf Günter Rohrmann; Sebastian Thöns; Werner Rücker

2010-01-01

145

Power control of a wind farm with active stall wind turbines and AC grid connection  

E-print Network

Power control of a wind farm with active stall wind turbines and AC grid connection Anca D. Hansen1 controller for a wind farm made-up exclusively of active stall wind turbines with AC grid connection wind farm control involves both the control on wind turbine level as well as the central control

146

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

Microsoft Academic Search

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

A. Makkawi; AN Celik; T. Muneer

2009-01-01

147

Optimal control of wind turbine using neural networks  

Microsoft Academic Search

Variable-speed, fixed-pitch wind turbines are required to optimize power output performance without the aerodynamic controls. In steady-state, a wind turbine generator system is operated such that the optimum points of wind rotor curve and electrical generator curve coincide. In order to obtain maximum power output of a wind turbine generator system, it is necessary to drive the wind turbine at

Mahinsasa Narayana; Ghanim Putrus

2010-01-01

148

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

SciTech Connect

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

149

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

SciTech Connect

This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. In total, four turbines were tested at the National Wind Technology Center (NWTC) as a part of this project. Safety and function testing is one of up to five tests that were performed on the turbines, including power performance, duration, noise, and power quality tests. Test results provide manufacturers with reports that can be used for small wind turbine certification. The test equipment includes an ARE 442 wind turbine mounted on a 100-ft free-standing lattice tower. The system was installed by the NWTC Site Operations group with guidance and assistance from Abundant Renewable Energy.

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

2010-02-01

150

Mod2 wind turbine field operations experience  

Microsoft Academic Search

The three-machine, 7.5 MW Goodnoe Hills cluster, located near Goldendale, Washington, is now in a research\\/experimental operations phase that offers a unique opportunity to study the effects of single and multiple wind turbines interacting with each other, the power grid; and the environment. Following a brief description of the turbine and project history, this paper addresses major problem areas and

1985-01-01

151

Mod2 wind turbine field operations experiment  

Microsoft Academic Search

The three-machine, 7.5 MW Goodnoe Hills located near Goldendale, Washington and is now in a research\\/experimental operations phase that offers a unique opportunity to study the effects of single and multiple wind turbines interacting with each other, the power grid; and the environment. Following a brief description of the turbine and project history, this paper addresses major problem areas and

L. H. Gordon

1985-01-01

152

Magnus wind turbines as an alternative to the blade ones  

NASA Astrophysics Data System (ADS)

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

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

2007-07-01

153

Wind Turbine. Final Quarterly Project Report, January-April 1981.  

National Technical Information Service (NTIS)

A 16 ft diameter wind turbine of fiberglass/foam construction was constructed to drive a 4000W/230 VAC alternator. Data are given on the wind turbine's output. Project expenses are tabulated. (ERA citation 10:023726)

W. D. Racine

1981-01-01

154

A doubly-fed permanent magnet generator for wind turbines  

E-print Network

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

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

2004-01-01

155

Advanced wind turbine design studies: Advanced conceptual study  

Microsoft Academic Search

In conjunction with the US Department of Energy and the National Renewable Energy Laboratory's Advanced Wind Turbine Program, the Atlantic Orient Corporation developed preliminary designs for the next generation of wind turbines. These 50 kW and 350 kW turbines are based upon the concept of simplicity. By adhering to a design philosophy that emphasizes simplicity, we project that these turbines

P. Hughes; R. Sherwin

1994-01-01

156

Wind turbine blade aerodynamics: The combined experiment  

SciTech Connect

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

Robinson, M.C.; Luttges, M.W.; Miller, M.S.; Shipley, D.E.; Young, T.S. [Colorado Univ., Boulder, CO (United States). Dept. of Aerospace Engineering Sciences

1994-08-01

157

Aileron controls for wind turbine applications  

NASA Technical Reports Server (NTRS)

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

Miller, D. R.; Puthoff, R. L.

1984-01-01

158

Aileron controls for wind turbine applications  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

159

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

Microsoft Academic Search

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

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

2008-01-01

160

The Effect of Wind Speed and Electric Rates On Wind Turbine Economics  

E-print Network

The Effect of Wind Speed and Electric Rates On Wind Turbine Economics Economics of wind power depends mainly on the wind speeds and the turbine make and model. Definition: Simple Payback The "Simple period of a small wind power project. All the figures are per turbine, so it can be used for a one, two

Massachusetts at Amherst, University of

161

SAR-BASED WIND CLIMATOLOGY FOR WIND TURBINES Merete Bruun Christiansen(1)  

E-print Network

SAR-BASED WIND CLIMATOLOGY FOR WIND TURBINES Merete Bruun Christiansen(1) , Charlotte Bay Hasager(1 of interest. 1. OFFSHORE WIND ENERGY Wind turbines are being installed at offshore locations in several and the energy density can be derived. Different configurations of wind turbines may be tested in WAs

162

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

163

Wind Scanner: A full-scale Laser Facility for Wind and Turbulence Measurements around large Wind Turbines  

E-print Network

Turbines Torben Mikkelsen, Jakob Mann and Michael Courtney Wind Energy Department, Risø National Laboratory measurements of the wind fields engulfing today's huge wind turbines. Our aim is to measure in real- time 3D wind vector data at several hundred points every second: 1) in front of the turbine, 2) at the turbine

164

Wind Turbine Contingency Control Through Generator De-Rating  

NASA Technical Reports Server (NTRS)

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

Frost, Susan; Goebel, Kai; Balas, Mark

2013-01-01

165

Study on Lightning Protection Methods for Wind Turbine Blades  

Microsoft Academic Search

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

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

2005-01-01

166

Assessment of fatigue life for small composite wind turbine blades  

Microsoft Academic Search

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

Jia-Hroung Wu

2010-01-01

167

Doctoral Position Aeroelastic Analysis of Large Wind Turbines  

E-print Network

¨adikat behindertenfreundlich") for its efforts with respect to training and employment of severely disabled peopleDoctoral Position Aeroelastic Analysis of Large Wind Turbines In the research project "Aeroelastic Analysis Horizontal-axis wind turbine and numerical model. of Large Wind Turbines" funded by the Ger- man

168

Quantifying the hurricane risk to offshore wind turbines  

E-print Network

Quantifying the hurricane risk to offshore wind turbines Stephen Rosea , Paulina Jaramilloa,1 GW will be required from shallow offshore turbines. Hurricanes are a potential risk to these turbines be destroyed by hurricanes in an offshore wind farm. We apply this model to estimate the risk to offshore wind

Jaramillo, Paulina

169

Research on fault mechanism of icing of wind turbine blades  

Microsoft Academic Search

In this paper, fault mechanism of icing of wind turbine blades is studied theoretically and experimentally. First, the aerodynamic performance of a wind turbine's primary airfoil under normal and icing conditions are simulated using Fluent software separately to analyze the geometry effect of icing on wind turbine. Then the formation and characteristics of vibration signal on main shaft caused by

Minghao Zhao; Dongxiang Jiang; Shaohua Li

2009-01-01

170

Dynamics and Fatigue Damage of Wind Turbine Rotors  

E-print Network

6 3 RiS0-Rr512 Dynamics and Fatigue Damage of Wind Turbine Rotors during Steady Operation Peter OF WIND TURBINE ROTORS DURING STEADY OPERATION Peter Hauge Madsen, Sten Frandsen, William E. Holley-carrying capacity of a wind turbine rotor with respect to short-term strength and material fatigue are presented

171

Control of Wind Turbines for Power Regulation and  

E-print Network

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

172

Offshore Series Wind Turbine Variable Hub heights & rotor diameters  

E-print Network

3.6MW Offshore Series Wind Turbine GE Energy #12;Feature Variable Hub heights & rotor diameters harmonious function within the local grid Allows wind turbines to stay on line generating power, even during-savings feature, considering the rigors of offshore power generation. The 3.6 MW offshore wind turbine also

Firestone, Jeremy

173

Fast Verification of Wind Turbine Power Summary of Project Results  

E-print Network

Fast Verification of Wind Turbine Power Curves: Summary of Project Results by: Cameron Brown ­ s equation on high frequency wind turbine measurement data sampled at one sample per second or more. The aim's Nordtank wind turbine at the Risø site, the practical application of this new method was tested

174

Initialization of wind turbine models in power system dynamics simulations  

Microsoft Academic Search

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

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

2001-01-01

175

ACOUSTIC STUDY OF THE UD / GAMESA WIND TURBINE PROJECT  

E-print Network

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

Firestone, Jeremy

176

Disturbance Control of the Hydraulic Brake in a Wind Turbine  

E-print Network

Disturbance Control of the Hydraulic Brake in a Wind Turbine Frank Jepsen, Anders Søborg brake in a wind turbine. Brake torque is determined by friction coefficient and clamp force; the latter brake is one1 of the two independent brake systems in a wind turbine. As a consequence of the gearing

Yang, Zhenyu

177

Flicker emission of wind turbines during continuous operation  

Microsoft Academic Search

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

Åke Larsson

2002-01-01

178

EFFECTS OF FIBER WAVINESS ON COMPOSITES FOR WIND TURBINE BLADES  

E-print Network

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

179

Mechanisms of amplitude modulation in wind turbine , A. J. Bullmoreb  

E-print Network

Mechanisms of amplitude modulation in wind turbine noise M. Smitha , A. J. Bullmoreb , M. M. Candb produced by wind turbines is inherently time varying. This amplitude modulation is normally due The environmental noise impact of wind turbine generators has to be assessed when planning new installations

Paris-Sud XI, Université de

180

SOUND COMPLIANCE MONITORING FOR THE GAMESA WIND TURBINE  

E-print Network

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

Firestone, Jeremy

181

Dynamic wind turbine models in power system simulation tool  

E-print Network

Dynamic wind turbine models in power system simulation tool DIgSILENT Anca D. Hansen, Florin Iov Iov, Poul Sørensen, Nicolaos Cutululis, Clemens Jauch, Frede Blaabjerg Title: Dynamic wind turbine system simulation tool PowerFactory DIgSILENT for different wind turbine concepts. It is the second

182

IMPLEMENTATION OF WIND TURBINE CONTROLLERS W.E.Leithead  

E-print Network

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

Duffy, Ken

183

Micro, midi or macro? Onshore wind turbine economics for Scotland  

Microsoft Academic Search

This article investigates the feasibility of the application of wind turbine as a means of offsetting the electricity demand for public buildings within Scotland. A number of case studies are presented with respect to currently operational micro-, midi- and macro wind turbines within England and Scotland. Presently, the micro-, midi- and macro wind turbines have been categorised as those that

A. Makkawi; N. Gupta; T. Muneer

2008-01-01

184

Comparison and evaluation of three main types of wind turbines  

Microsoft Academic Search

Many different types of wind turbines have been connected to the power systems of the world in recent years, and their primary focus was to design them to be more efficient and reliable. In this paper, three main types of wind turbines are modeled and compared. The performances of these wind turbines during a severe three-phase fault at the end

Yi Zhang; Sadrul Ula

2008-01-01

185

Wind turbine availability analysis based on statistical data  

Microsoft Academic Search

Availability is an important performance index for wind turbines. To predict wind turbine availability, failure rate and repair rate have to be known. There are some sources of wind turbine failure data that can be used to estimate parameters of the failure rate function and the repair rate. With repair rate assumed to be constant, this paper first presents maximum

Haitao Guo; Xianhui Yang; Jianping Xiang; Simon Watson

2009-01-01

186

Operation of a third generation wind turbine  

SciTech Connect

A modern wind turbine was installed on May 26, 1982, at the USDA Conservation and Production Research Laboratory, Bushland, Texas. This wind machine was used to provide electrical energy for irrigation pumping and other agricultural loads. The wind turbine purchased for this research is an Enertech Model 44, manufactured by Enertech Corporation, Norwich, Vermont. The horizontal-axis wind turbine has a 13.4 m diameter, three-bladed, fixed-pitch rotor on a 24.4-m tower. The blades are laminated epoxy-wood, and are attached to a steel hub. A 25-kW induction generator provides 240 V, 60 Hz, single-phase electrical power. The wind turbine operated 64 percent of the time, while being available to operate over 94 percent of the time. The unit had a net energy production of over 80,000 kWh in an average windspeed of 5.9 m/s at a height of 10 m in a 16-month period. The blade pitch was originally offset two degrees from design to maintain power production within the limitations of the gearbox, generator, and brakes. A maximum output of 23.2 kW averaged over a 15-second period indicated that with a new brake, the system was capable of handling more power. After a new brake was installed, the blade pitch was changed to one degree from design. The maximum power output measured after the pitch change was 29.3 kW. Modified blade tip brakes were installed on the wind turbine on July 7, 1983. These tip brakes increased power production at lower windspeeds while reducing power at higher windspeeds.

Vosper, F.C.; Clark, R.N.

1983-12-01

187

Built-Environment Wind Turbine Roadmap  

SciTech Connect

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

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

2012-11-01

188

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

SciTech Connect

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

Miller, S.

1988-05-01

189

Hydrogen Storage in Wind Turbine Towers  

SciTech Connect

Low-cost hydrogen storage is recognized as a cornerstone of a renewables-hydrogen economy. Modern utility-scale wind turbine towers are typically conical steel structures that, in addition to supporting the rotor, could be used to store hydrogen. This study has three objectives: (1) Identify the paramount considerations associated with using a wind turbine tower for hydrogen storage; (2)Propose and analyze a cost-effective design for a hydrogen-storing tower; and (3) Compare the cost of storage in hydrogen towers to the cost of storage in conventional pressure vessels. The paramount considerations associated with a hydrogen tower are corrosion (in the form of hydrogen embrittlement) and structural failure (through bursting or fatigue life degradation). Although hydrogen embrittlement (HE) requires more research, it does not appear to prohibit the use of turbine towers for hydrogen storage. Furthermore, the structural modifications required to store hydrogen in a tower are not cost prohibitive.

Kottenstette, R.; Cotrell, J.

2003-09-01

190

Infrasound from Wind Turbines Could Affect Humans  

ERIC Educational Resources Information Center

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

Salt, Alec N.; Kaltenbach, James A.

2011-01-01

191

Monitoring system of wind turbine rotor blades  

Microsoft Academic Search

Conventionally, modal monitoring of Wind Turbine Rotor Blades is primarily based on the evaluation of eigenfrequencies. Beyond this, combining a sensor network with the Operational Modal Analysis (OMA) method, mode shape and parallely a local component are utilized here. In addition it is expected that the damping, which is also determined by the OMA method, will give a lead on

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

2009-01-01

192

Wind turbine performance under icing conditions  

SciTech Connect

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

Jasinski, W.J.; Noe, S.C.; Selig, M.S.; Bragg, M.B. [Univ. of Illinois, Urbana, IL (United States). Dept. of Aeronautical and Astronautical Engineering

1998-02-01

193

Lightning current monitoring system for wind turbines  

Microsoft Academic Search

Lightning protection and surge protection measures are essential for the availability of wind turbines and for their profitability. Whereas the electric and electronic equipment can be protected by a comprehensive surge protection concept, outer structures particularly the rotor blades are hit by direct lightning strikes. In defined maintenance cycles these damages are inspected and repaired in costly operations. In this

Martin Wetter; Arno Kiefer; Achim Zirkel

2011-01-01

194

Lightning protection for wind turbine electronics  

Microsoft Academic Search

Preventive measures for the protection of wind turbines from lightning strike damage are outlined. Lightning can dissipate up to a billion joules in less than a second while electronic components have tolerances in the microjoule range. Structural members may also suffer damage by mechanical stresses due to parallel conductance of lightning amperage; millions of volts are capable of causing flashovers

D. L. Begley; C. W. Dodd; T. M. McCalla Jr.

1981-01-01

195

Fault tolerant generator systems for wind turbines  

Microsoft Academic Search

The objective of this paper is to review the possibilities of applying fault tolerance in generator systems for wind turbines based on what has been presented in the literature. In order to make generator systems fault tolerant in a suitable way, it is necessary to gain insight into the probability of different failures, so that suitable measures can be taken.

H. Polinder; H. Lendenmann; R. Chin; W. M. Arshad

2009-01-01

196

Wind Turbine Tribology Seminar - A Recap  

SciTech Connect

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

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

2012-02-01

197

LOAD DATA ANALYSIS FOR WIND TURBINE GEARBOXES  

Microsoft Academic Search

Gearboxes for wind turbines have to ensure highest reliability over a period of approximately 20 years, withstanding high dynamic loads. At the same time lightweight design and cost minimization are required. These demands can only be met by a thought-out design, high-quality materials, high production quality and maintenance. In order to design a reliable and lightweight gearbox it is necessary

Bernd Niederstucke; Andreas Anders; Peter Dalhoff; Rainer Grzybowski; Germanischer Lloyd

198

On-condition maintenance for wind turbines  

Microsoft Academic Search

This work presents a system to manage wind turbines maintenance through a predictive model. The system is based on specific maintenance software and hardware for data acquisition and also on algorithms for prediction based on time series. The maintenance software is called SMIT - (Terology Integrated Modular System). The acquisition system can be interconnected with professional, industrial and low cost

Inácio Fonseca; Torres Farinha; F. Maciel Barbosa

2009-01-01

199

Wind Turbine Tribology Seminar - A Recap  

Microsoft Academic Search

Tribology is the science and engineering of interacting surfaces in relative motion. It includes the study and application of the principles of friction, lubrication, and wear. It is an important phenomenon that not only impacts the design and operation of wind turbine gearboxes, but also their subsequent maintenance requirements and overall reliability. With the major growth and increasing dependency on

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

2012-01-01

200

Learning in wind turbine development  

Microsoft Academic Search

Both the Netherlands and Denmark started to develop wind energy in the 1970s. Reasons were the oil crisis and the Club of Rome report, which warned of imminent shortages of traditional energy sources like oil and gas. Both countries started this development around 1975 and their governments gave active support. Furthermore, both countries have a comparable wind regime. However, the

Linda Manon Kamp

2002-01-01

201

innovati nNREL Computer Models Integrate Wind Turbines with  

E-print Network

of energy-hungry coastal cities, powerful winds blow over the open ocean, where the water is too deep wind energy resources, wind turbines must be mounted on floating platforms to be cost effectiveinnovati nNREL Computer Models Integrate Wind Turbines with Floating Platforms Far off the shores

202

Periodic pulsations from a three-bladed wind turbine  

Microsoft Academic Search

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

Torbjörn Thiringer; Jan-Åke Dahlberg

2001-01-01

203

A Review of Micro Wind Turbines in the Built Environment  

Microsoft Academic Search

As distributed small-scale generate system integrated into built environment, micro wind turbines are being on the way to commercial market. But there is complexity in small-scale wind system differed from traditional wind system because of the particularity of built environment. This paper provides an overall review of micro wind turbines research in the built environment. The configuration forms, key technical

Dong Li; Shujie Wang; Peng Yuan

2010-01-01

204

Evolution and Reduction of Scour around Offshore Wind Turbines  

Microsoft Academic Search

Evolution and Reduction of Scour around Offshore Wind Turbines In response to growing socio-economic and environmental demands, electricity generation through offshore wind turbine farms is a fast growing sector of the renewable energy market. Considerable numbers of offshore wind farms exist in the shallow continental shelf seas of the North-West Europe, with many more in the planning stages. Wind energy

David McGovern; Suzana Ilic

2010-01-01

205

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

E-print Network

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

Hu, Hui

206

Response of a Vertical Axis Wind Turbine to Time Varying Wind Conditions found within the Urban  

E-print Network

Response of a Vertical Axis Wind Turbine to Time Varying Wind Conditions found within the Urban, 2010 PP 389­401 389 ABSTRACT Experimental testing of a vertical axis wind turbine within the urban of the turbine. Temporal variation of the wind with respect to the direction and velocity fluctuations

Tullis, Stephen

207

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

E-print Network

1 WIND-TUNNEL STUDY ON AERODYNAMIC PERFORMANCE OF SMALL VERTICAL-AXIS WIND TURBINES J. J. Miau*1 were carried out to study the aerodynamic performance of three vertical axis wind turbines (VAWTs. On the other hand, the characteristics of unsteady flow around the helical wind turbine were studied with a hot

Leu, Tzong-Shyng "Jeremy"

208

Implications of the effects of wind characteristics on the operation of large wind turbines  

Microsoft Academic Search

The Wind Characteristics Program Element of the DOE Wind Systems Branch is examined. Three subtasks are considered: wind energy prospecting; wind characteristics for design, performance evaluation, and operations; and site evaluation. Attention is given to how wind characteristics affect the overall performance of large wind turbines. The first simulation of turbine output lends support to the potential need for site-specific

A. H. Miller

1980-01-01

209

Probabilistic fatigue methodology and wind turbine reliability  

SciTech Connect

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

210

Dynamic Models for Wind Turbines and Wind Power Plants  

SciTech Connect

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

211

Mod-2 wind turbine field operations experiment  

NASA Astrophysics Data System (ADS)

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

Gordon, L. H.

1985-12-01

212

Dynamic behavior of variable speed wind turbines under stochastic wind  

Microsoft Academic Search

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

S. A. Papathanassiou; M. P. Papadopoulos

1999-01-01

213

Roof mounting site analysis for micro-wind turbines  

Microsoft Academic Search

Building-integrated micro-wind turbines are promising low-cost renewable energy devices. However, the take-up of micro-wind turbines in high density suburban environments is still very limited due to issues such as: a) low wind speeds; b) high turbulence intensity; and c) the perception of potentially high levels of aerodynamic noise generated by the turbines. The wind flow field above the roof of

L. Ledo; P. B. Kosasih; P. Cooper

2011-01-01

214

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

NASA Technical Reports Server (NTRS)

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

1982-01-01

215

Braking System for Wind Turbines  

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

216

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

NASA Technical Reports Server (NTRS)

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

Park, G. L.

1982-01-01

217

Control of large wind turbine generators connected to utility networks  

NASA Technical Reports Server (NTRS)

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

Hinrichsen, E. N.

1983-01-01

218

Causes of Bat Fatalities at Wind Turbines: Hypotheses and Predictions  

Microsoft Academic Search

Thousands of industrial-scale wind turbines are being built across the world each year to meet the growing demand for sustainable energy. Bats of certain species are dying at wind turbines in unprecedented numbers. Species of bats consistently affected by turbines tend to be those that rely on trees as roosts and most migrate long distances. Although considerable progress has been

Paul M. Cryan; Robert M. R. Barclay

2009-01-01

219

Wind Turbine Tower Optimization Method Using a Genetic Algorithm  

Microsoft Academic Search

A wind turbine tower optimization program was developed, using a genetic algorithm. This allowed a rational analysis to reduce the mass of turbine tower, by considering, for example, the distributions of diameter and wall thickness, and the positions of flanges and access ports to navigation lights. Both extreme and fatigue loads were calculated, based on wind turbine design requirements and

Shigeo Yoshida

2006-01-01

220

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

Microsoft Academic Search

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

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

1997-01-01

221

International collaborative research in wind turbine rotor aerodynamics  

Microsoft Academic Search

Five organizations from four countries are collaborating to conduct detailed wind turbine aerodynamic test programs. Fullscale atmospheric testing will be conducted on turbines configured to measure aerodynamic forces on rotating airfoils. The purpose of these test programs is to come to a better understanding of the steady and unsteady aerodynamic behavior of wind turbine rotors, and provide information needed to

D. A. Simms; C. P. Butterfield

1993-01-01

222

Gearing ratios of a magnetic gear for wind turbines  

Microsoft Academic Search

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

Nicolas W. Frank; Hamid A. Toliyat

2009-01-01

223

Utility Scale Wind turbine Demonstration Project  

SciTech Connect

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

Terry Fredericks

2006-03-31

224

66 APRIL | 2010 The FuTure oF Wind Turbine  

E-print Network

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

Kusiak, Andrew

225

Composite Materials for Wind Power Turbine Blades  

NASA Astrophysics Data System (ADS)

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

Brøndsted, Povl; Lilholt, Hans; Lystrup, Aage

2005-08-01

226

Root region airfoil for wind turbine  

DOEpatents

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

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

1995-05-23

227

10 MW Class Superconductor Wind Turbine Generators  

Microsoft Academic Search

High temperature superconductor (HTS) technology enables generators with one third the weight and one half the losses of conventional machines. These technologies enable a significant reduction in the size and weight of 10 MW-class generators for direct-drive wind turbine systems and reduce the cost of clean energy relative to conventional copper and perma- nent-magnet-based generators and gearboxes. With compact and

Gregory Snitchler; Bruce Gamble; Christopher King; Peter Winn

2011-01-01

228

Mod 2 wind turbine development project  

NASA Astrophysics Data System (ADS)

A wind turbine to produce energy for less than 5 cents/kWh based on 1980 cost forecasts was designed. The pricing method used to project the Mod 2 energy costs is the levelized fixed charge rate approach, generally accepted in the electric utility industry as a basis for relative ranking of energy alternatives. This method derives a levelized energy price necessary to recover utility's purchasing, installing, owning, operating, and maintenance costs.

1980-10-01

229

Mod 2 Wind Turbine Development Project  

SciTech Connect

The primary objective in the development of Mod 2 was to design a wind turbine to produce energy for less than 5 cents/kWh based on 1980 cost forecasts. The pricing method used to project the Mod 2 energy costs is the levelized fixed charge rate approach, generally accepted in the electric utility industry as a basis for relative ranking of energy alternatives. This method derives a levelized energy price necessary to recover utility's purchasing, installing, owning, operating, and maintenance costs.

None

1980-10-01

230

Flow separation on wind turbines blades  

NASA Astrophysics Data System (ADS)

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

Corten, G. P.

2001-01-01

231

Survey of modelling methods for wind turbine wakes and wind farms  

Microsoft Academic Search

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

A. Crespo; J. Hernández; S. Frandsen

1999-01-01

232

WEST-3 wind turbine simulator development  

NASA Technical Reports Server (NTRS)

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

Hoffman, J. A.; Sridhar, S.

1985-01-01

233

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

NASA Astrophysics Data System (ADS)

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

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

234

An overview of DOE's wind turbine development programs  

NASA Astrophysics Data System (ADS)

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

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

1992-12-01

235

Urban wind energy conversion: The potential of ducted turbines  

Microsoft Academic Search

The prospects for urban wind power are discussed. A roof-mounted ducted wind turbine, which uses pressure differentials created by wind flow around a building, is proposed as an alternative to more conventional approaches. Outcomes from tests at model and prototype scale are described, and a simple mathematical model is presented. Predictions from the latter suggest that a ducted turbine can

Andrew Grant; Cameron Johnstone; Nick Kelly

2008-01-01

236

State estimation for wind turbine system based on Kalman filter  

Microsoft Academic Search

Consider the parameter uncertainty of the wind power station, wind turbine system state space model with uncertainty and disturb is modeled. State estimation Kalman filter for wind turbine system is designed based on Kalman filter theory. The effectiveness of the proposed Kalman filter is demonstrated with a simulation example.

Huo Zhihong; Zheng Yuan; Xu Chang

2008-01-01

237

Trailing Edge Noise Model Applied to Wind Turbine Airfoils  

E-print Network

Trailing Edge Noise Model Applied to Wind Turbine Airfoils Franck Bertagnolio Risø-R-1633(EN) Risø Bertagnolio Title: Trailing Edge Noise Model Applied to Wind Turbine Airfoils Department: Wind Energy in the optimization process of two reference airfoils in order to reduce their noise signature: the RIS�-B1

238

Review of failures and condition monitoring in wind turbine generators  

Microsoft Academic Search

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

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

2010-01-01

239

Demonstration project: wind turbines for municipal water pumping  

Microsoft Academic Search

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

1982-01-01

240

Safety-factor calibration for wind turbine extreme loads  

Microsoft Academic Search

Proper prediction of long-term extreme values for operating wind turbine loads and deflections is a critical component of wind turbine design. Direct observations or simulations of long-term extremes are not yet available; therefore, these predictions rely on some combination of large numbers of simulations and extrapolation. Extrapolation methods themselves can have significant uncertainty, and they also require that the wind

Patrick Moriarty

2008-01-01

241

Demonstration of the Ability of RCAS to Model Wind Turbines  

Microsoft Academic Search

In recent years, the wind industry has sponsored the development, verification, and validation of comprehensive aeroelastic simulators, which are used for wind turbine design, certification, and research. Unfortunately, as wind turbines continue to grow in size and sometimes exhibit unconventional design characteristics, the existing codes do not always support the additional analysis features required for proper design. The development history,

J. Jonkman; J. Cotrell

2003-01-01

242

An experimental and numerical study of wind turbine seismic behavior  

E-print Network

history of ground motions and response at top of nacelle Figure 3.1: Wind turbinehistories to be applied in con- junction with other load sources for wind turbines.history to be applied in conjunction with other load sources for wind turbines.

Prowell, I.

2011-01-01

243

Wind turbine concentrator design based on moist air phase change  

Microsoft Academic Search

This current article shows a procedure to improve wind turbines for kinetic energy conversion in mechanics using a new concentrating design based on moist air phase change. This concentrator presents special interest in the European Atlantic Coast because its weather is mild with a high relative humidity and its winds represent low values for wind turbines applications. Results show a

J. A. Orosa; E. J. Garcia-Bustelo; J. A. Perez

2009-01-01

244

Site-specific Design Optimization of Wind Turbines  

Microsoft Academic Search

This article reports results from a European project, where site characteristics were incorporated into the design process of wind turbines, to enable site-specific design. Two wind turbines of different concept were investigated at six different sites comprising normal flat terrain, offshore and complex terrain wind farms. Design tools based on numerical optimization and aeroelastic calculations were combined with a cost

P. Fuglsang; C. Bak; J. G. Schepers; B. Bulder; T. T. Cockerill; P. Claiden; A. Olesen; R. van Rossen

2002-01-01

245

A System for Connecting the Wind Turbines to Power Grid  

Microsoft Academic Search

Generating electrical energy by the alternative energy resources is getting popular as the cost of generating electricity using alternative energy sources is getting cheaper. One of the most popular alternative electrical energy generation method is the wind turbines. The asynchronous character of the wind turbines creates the problem of integrating the generated wind power to the main grid. Converters are

O. C. Ozerdem

2007-01-01

246

Innovative design approaches for large wind turbine blades  

Microsoft Academic Search

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

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

2005-01-01

247

Modeling and control of a small wind turbine  

Microsoft Academic Search

This paper starts with a detailed survey of control methods commonly employed by commercially available small wind turbines. This detailed survey indicates that the most commonly used control method of small wind turbines is horizontal furling method. Such furling mechanism and resulting dynamics are described in the paper. Furling is used to control the aerodynamic power extraction from the wind.

M. Arifujjaman; M. T. Iqbal; J. E. Ouaicoe; M. J. Khan

2005-01-01

248

A robust wind turbine control using a Neural Network based wind speed estimator  

Microsoft Academic Search

Modern wind turbines are capable to work in variable speed operations. These wind turbines are provided with adjustable speed generators, like the double feed induction generator. One of the main advantage of adjustable speed generators is that they improve the system efficiency compared to fixed speed generators because turbine speed is adjusted as a function of wind speed to maximize

Oscar Barambones

2010-01-01

249

Alternative methods of estimating hub-height wind speed for small wind turbine performance evaluation  

Microsoft Academic Search

Current industry standards for evaluating wind turbine power performance require erecting a meteorological mast on site to obtain reference measurements of hub-height wind speed. New considerations for small wind turbines (SWTs) offer the alternative of using an anemometer extending from a lower elevation on the turbine tower. In either case, SWT owners face questions and impracticalities when applying this standard

Brett Ziter

2010-01-01

250

Infrasound, the Ear and Wind Turbines Alec N. Salt, Ph.D.  

E-print Network

2004; 116:3460 #12;Sound from Windmills:Sound from Windmills: Wind Turbine SyndromeWind TurbineInfrasound, the Ear and Wind Turbines Alec N. Salt, Ph.D. Department of Otolaryngology there happens to be a castle nearby). #12;Wind turbines haveWind turbines have been getting biggerbeen getting

Salt, Alec N.

251

36 SEPTEMBER | 2012 WiNd TURbiNE CAPACiTY  

E-print Network

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

Kusiak, Andrew

252

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

Microsoft Academic Search

In conjunction with the US Department of Energy and the National Renewable Energy Laboratory`s Advanced Wind Turbine Program, the Atlantic Orient Corporation developed preliminary designs for the next generation of wind turbines. These 50 kW and 350 kW turbines are based upon the concept of simplicity. By adhering to a design philosophy that emphasizes simplicity, we project that these turbines

P. Hughes; R. Sherwin

1994-01-01

253

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

SciTech Connect

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

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

2012-03-05

254

Remote monitoring and nondestructive evaluation of wind turbine towers  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

255

Superconductivity for Large Scale Wind Turbines  

SciTech Connect

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

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

2012-10-12

256

Wind turbine testing in the NREL dynamometer test bed  

Microsoft Academic Search

A new facility has recently been completed at the National Renewable Energy Laboratory that allows full-scale dynamometer testing of wind turbine components, from generators to complete wind turbines. This facility is equipped with a 2.5 MW motor, gearbox, and variable speed drive system to deliver shaft torque. To simulate other aspects of wind turbine loading an MTS fatigue-rated loading system

Walt Musial; Brian McNiff

2000-01-01

257

Power and energy analysis of commercial small wind turbine systems  

Microsoft Academic Search

Small wind turbines harvest wind energy to provide carbon free energy for residential and small commercial applications. Current technology consists of a diode-bridge rectifier and an off-the-shelf generator. Such a simplified system does not utilize the full capacity of the turbine because the generator drive system is not designed specifically for wind turbine applications. This paper presents the technology that

Nikola Milivojevic; Igor Stamenkovic; Nigel Schofield

2010-01-01

258

Dynamic modeling of doubly fed induction generator wind turbines  

Microsoft Academic Search

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

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

2003-01-01

259

Overview of wind turbine siting research: Prospecting to micrositing  

Microsoft Academic Search

The Federal Wind Energy Program of the United States' Department of Energy has directed research in wind behavior relevant to the economic extraction of power from the wind. The variability of the wind in time and space is important in this process. Topics of research related to wind turbine siting have included resource assessment, siting techniques, and techniques for documenting

L. L. Wendell

1985-01-01

260

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

NASA Technical Reports Server (NTRS)

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

Eberle, W. R.

1981-01-01

261

Analysis of the Environmental Impact on Remanufacturing Wind Turbines  

NASA Astrophysics Data System (ADS)

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

Sosa Skrainka, Manuel R.

262

Spatial mapping and attribution of Wyoming wind turbines, 2012  

USGS Publications Warehouse

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

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

2014-01-01

263

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

E-print Network

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

264

Lightning protection of wind turbines — A comparison of lightning data & IEC 61400-24  

Microsoft Academic Search

IEC 61400-24 dealing with lightning protection of wind turbines was first introduced in 2002. This was initially developed as a technical report. Since then, wind power has been rapidly developing with wind turbine manufacturers developing larger wind turbines which are at an increased risk of lightning strikes. With the move of large wind farms offshore, maintenance of wind turbines also

Vidyadhar Peesapati; Ian Cotton

2009-01-01

265

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

Federal Register 2010, 2011, 2012, 2013

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

2011-09-01

266

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

Federal Register 2010, 2011, 2012, 2013

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

2012-06-01

267

DAMAGE DETECTION METHODS ON WIND TURBINE BLADE TESTING WITH WIRED AND WIRELESS ACCELEROMETER SENSORS  

E-print Network

DAMAGE DETECTION METHODS ON WIND TURBINE BLADE TESTING WITH WIRED AND WIRELESS ACCELEROMETER for nonstationary blade excitations. KEYWORDS : Structural Health Monitoring, Damage Detection, Wind Turbine, Wireless sensing, Wavelets. INTRODUCTION Detecting damage in wind turbine blades is a very

Paris-Sud XI, Université de

268

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

ERIC Educational Resources Information Center

People who live near wind turbines complain of symptoms that include some combination of the following: difficulty sleeping, fatigue, depression, irritability, aggressiveness, cognitive dysfunction, chest pain/pressure, headaches, joint pain, skin irritations, nausea, dizziness, tinnitus, and stress. These symptoms have been attributed to the…

Havas, Magda; Colling, David

2011-01-01

269

Wind Turbine Drivetrain Condition Monitoring - An Overview (Presentation)  

SciTech Connect

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

Sheng, S.; Yang, W.

2013-07-01

270

Basic Integrative Models for Offshore Wind Turbine Systems  

E-print Network

.com) ................................................... 20 17 David Fisher?s Swirling Skyscraper (gizmag.com) ................................................... 20 viii FIGURE Page 18 Offshore Wind Turbine, the Aerogenerator X (gizmodo.com)................................... 22 19 Siemens Hywind... the three wind turbines with greater wind stream. An example from dynamic architecture is David Fisher?s rather unique design of a wind-powered, rotating skyscraper, which features 80 independently-rotating floors and is expected to be the world?s first...

Aljeeran, Fares

2012-07-16

271

Adaptive inverse control of variable speed wind turbine  

Microsoft Academic Search

The efficiency and reliability of wind power has been shown to be depending on the applied control strategy of the wind turbine.\\u000a In this paper, an adaptive control strategy is proposed for variable speed wind turbine (VSWT), producing energy limitation\\u000a above rated wind speed. In the proposed control strategy, the process is modeled using a neural networks based identifier,\\u000a providing

Yan Bao; Hui Wang; Jing Zhang

2010-01-01

272

Fatigue of fiberglass wind turbine blade materials  

NASA Astrophysics Data System (ADS)

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

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

1992-08-01

273

Model 0A wind turbine generator FMEA  

NASA Technical Reports Server (NTRS)

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

Klein, William E.; Lalli, Vincent R.

1989-01-01

274

Application of wind turbine energy yield data to verification of simulated wind fields  

NASA Astrophysics Data System (ADS)

Common datasets for wind field verification are often near-surface wind speed and wind direction data observed at the national weather stations. Those data have one major shortcoming. Measurements at near-surface heights are often disturbed by obstacles and roughness elements in their surrounding. Therefore those data represent the wind conditions in their nearest vicinity but not the wind field neither inside a model grid cell nor at larger heights. As an alternative one might think of wind turbine production data as a wind speed indicator. Hub height of wind turbines is around 100 m and a wind farm may well represent a model grid cell. A method for processing energy yield data from wind turbines in a north eastern region in Germany for application to wind field simulations will be presented. Differences and problems when using turbine output data instead of wind speed measurements will be discussed.

Paetzold, Anne; Mengelkamp, Heinz-Theo

2010-05-01

275

Aeroelastic stability analysis of a Darrieus wind turbine  

Microsoft Academic Search

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

D. Popelka

1982-01-01

276

Wind Turbine Gearbox Failure Modes - A Brief (Presentation)  

Microsoft Academic Search

Wind turbine gearboxes are not always meeting 20-year design life. Premature failure of gearboxes increases cost of energy, turbine downtime, unplanned maintenance, gearbox replacement and rebuild, and increased warranty reserves. The problem is widespread, affects most Original Equipment Manufacturers, and is not caused by manufacturing practices. There is a need to improve gearbox reliability and reduce turbine downtime. The topics

S. Sheng; M. McDade; R. Errichello

2011-01-01

277

Using of Composite Material in Wind Turbine Blades  

Microsoft Academic Search

The turbines manufactured from the mid 1980s until the late 1990s were mainly constructed using standard components. After that period, special components started being designed and manufactured for turbine use only. One of the best solutions is using composite materials in wind turbine. Most composites are made up of just two materials. One material (the matrix or binder) binds together

Bulent Eker; Aysegul Akdogan; Ali Vardar

2006-01-01

278

A hybrid wind turbine suitable for developing regions  

Microsoft Academic Search

In this article, a study is presented on a hybrid wind turbine which consists of two vertical axis coaxial turbines, one of Savonius type and the other a screw type. The Savonius type turbine rotates in a uniform velocity field while the second, the screw type converts the kinetic energy of the vortex flow generated in the center of the

E. Bilgen; I. Paraschivoiu; M. Kaine

1978-01-01

279

Research and development issues for small wind turbines  

Microsoft Academic Search

This paper discusses some of the major research and development issues for small wind turbines whose upper power limit we take arbitrarily as 50 kW. The basis for the comparison is the mature technology available for large turbines which has yet to be fully diffused downwards. After defining and categorising the important features of small turbines, the paper considers the

P. D. Clausen; D. H. Wood

1999-01-01

280

Wind turbine trailing edge aerodynamic brakes  

SciTech Connect

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

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

1995-04-01

281

Passive load control for large wind turbines.  

SciTech Connect

Wind energy research activities at Sandia National Laboratories focus on developing large rotors that are lighter and more cost-effective than those designed with current technologies. Because gravity scales as the cube of the blade length, gravity loads become a constraining design factor for very large blades. Efforts to passively reduce turbulent loading has shown significant potential to reduce blade weight and capture more energy. Research in passive load reduction for wind turbines began at Sandia in the late 1990's and has moved from analytical studies to blade applications. This paper discusses the test results of two Sandia prototype research blades that incorporate load reduction techniques. The TX-100 is a 9-m long blade that induces bend-twist coupling with the use of off-axis carbon in the skin. The STAR blade is a 27-m long blade that induces bend-twist coupling by sweeping the blade in a geometric fashion.

Ashwill, Thomas D.

2010-05-01

282

Wind power fluctuations mitigation by DC-Link voltage control of variable speed wind turbines  

Microsoft Academic Search

This paper presents a simulation model of a MW-level variable speed wind turbine with a permanent magnet synchronous generator (PMSG) and a full-scale converter developed in the simulation tool of PSCAD\\/EMTDC. Grid connected wind turbines are fluctuating power sources during continuous operation. A novel wind power fluctuations mitigation method by DC-link voltage control of variable speed wind turbines is proposed

Weihao Hu; Zhe Chen; Yue Wang; Zhaoan Wang

2008-01-01

283

LIGHTNING EXPOSURE OF WIND TURBINES University of Toronto  

E-print Network

LIGHTNING EXPOSURE OF WIND TURBINES Dale Dolan University of Toronto e-mail: dale@ecf.utoronto.ca Abstract This paper applies the electrogeometric model of lightning exposure to a wind turbine to compute its risk of damage due to a direct lightning strike in an area of known lightning flash density

Lehn, Peter W.

284

Lightning protection for wind turbine blades and bearings  

Microsoft Academic Search

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

Ian Cotton; Nick Jenkins; Krishnan Pandiaraj

2001-01-01

285

Dynamics and control of horizontal axis wind turbines  

Microsoft Academic Search

This tutorial paper describes the field of wind turbine control. It begins with the simplest turbine dynamic models and progresses to more advanced models which incorporate structural resonances in the blades and supporting tower. Disturbance accommodating control techniques are used to provide power control in fluctuating wind fields.

Mark J. Balas; Alan Wright; M. Hand; K. Stol

2003-01-01

286

Grid interface for a wind turbine-fuel cell system  

Microsoft Academic Search

Environmental and sustainability concerns are increasing the importance of distributed generation based on renewable energy sources and its grid integration. This paper proposes a grid interface for a hybrid system composed by fuel cells, a wind turbine and supercapacitors. Such grid interface permits to control the wind turbine energy using a diode rectifier and an intermediate DC boost converter and

E. Ribeiro; A. J. M. Cardoso; C. Boccaletti

2010-01-01

287

Dynamic simulation of dual-speed wind turbine generation  

Microsoft Academic Search

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

E. Muljadi; C. P. Butterfield

1996-01-01

288

Linear vibration analysis of rotating wind-turbine blade  

Microsoft Academic Search

In the wind-turbine design, linear vibration analysis of the wind-turbine blade should be performed to get vibratory characteristics and to avoid structural resonance. EOM (equations of motion) for the blade are derived and vibratory characteristics of a rotating blade are observed and discussed in this work. Linear vibration analysis requires the linearized EOM with DOF (degree of freedom). For the

Jung-Hun Park; Hyun-Yong Park; Seok-Yong Jeong; Sang-Il Lee; Young-Ho Shin; Jong-Po Park

2010-01-01

289

Dynamic Simulation of DFIG Wind Turbines on FPGA Boards  

E-print Network

Dynamic Simulation of DFIG Wind Turbines on FPGA Boards Hao Chen, Student Member, IEEE, Song Sun.10. The mechanical torque applied to the generator shaft is Tm == E2 Pm . Wr B. DFIG Control II. MODELING AND CONTROL of a dy- namic simulation of a doubly fed induction generator (DFIG)- based wind turbine on a field

Zambreno, Joseph A.

290

Methods and Apparatus for Rotor Load Control in Wind Turbines.  

National Technical Information Service (NTIS)

A wind turbine having a rotor, at least one rotor blade, and a plurality of generators, of which a first generator is configured to provide power to an electric grid and a second generator is configured to provide power to the wind turbine during times of...

E. M. Moroz

2004-01-01

291

General review of the MOSTAS computer code for wind turbines  

NASA Technical Reports Server (NTRS)

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

Dungundji, J.; Wendell, J. H.

1981-01-01

292

Fault ride-through capability of DFIG wind turbines  

Microsoft Academic Search

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

Anca D. Hansen; Gabriele Michalke

2007-01-01

293

Representing wind turbine electrical generating systems in fundamental frequency simulations  

Microsoft Academic Search

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

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

2003-01-01

294

Understanding the unbalanced-voltage problem in wind turbine generation  

Microsoft Academic Search

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

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

1999-01-01

295

Wind turbines emulating inertia and supporting primary frequency control  

Microsoft Academic Search

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

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

2006-01-01

296

Coupled Dynamic Modeling of Floating Wind Turbine Systems: Preprint  

Microsoft Academic Search

This article presents a collaborative research program that the Massachusetts Institute of Technology (MIT) and the National Renewable Energy Laboratory (NREL) have undertaken to develop innovative and cost-effective floating and mooring systems for offshore wind turbines in water depths of 10-200 m. Methods for the coupled structural, hydrodynamic, and aerodynamic analysis of floating wind turbine systems are presented in the

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

2006-01-01

297

Micro wind turbines in the UK domestic sector  

Microsoft Academic Search

The micro-scale wind turbine industry is expanding in the UK with institutional support and UK legislation encouraging the development of numerous companies with a profusion of design options. The application of micro wind turbines in urban environment is encouraged in the UK via a grant scheme which provides a proportion of the initial capital costs. This development is predicated on

A. D. Peacock; D. Jenkins; M. Ahadzi; A. Berry; S. Turan

2008-01-01

298

A probabilistic approach to wind turbine fatigue design  

Microsoft Academic Search

In wind turbine fatigue design it is customary to use the partial safety factor approach: loads are inflated by some factor, while material fatigue strength is decreased in calculations. Values for partial factors used originally come from civil engineering standards for utility buildings and bridges, and it is not clear that they are optimal for wind turbines. In the paper

Dick Veldkamp

299

Horizontal axis wind turbine systems: optimization using genetic algorithms  

Microsoft Academic Search

A method for the optimization of a grid-connected wind turbine system is presented. The behaviour of the system components is coupled in a non-linear way, and optimization must take into account technical and economical aspects of the complete system design. The annual electrical energy cost is estimated using a cost model for the wind turbine rotor, nacelle and tower and

T. Diveux; P. Sebastian; D. Bernard; J. R. Puiggali; J. Y. Grandidier

2001-01-01

300

Fault detection of large scale wind turbine systems  

Microsoft Academic Search

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

Xiukun Wei; Lihua Liu

2010-01-01

301

Fault estimation of large scale wind turbine systems  

Microsoft Academic Search

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

Wei Xiukun; Liu Lihua

2010-01-01

302

Further dual purpose evolutionary optimization of small wind turbine blades  

Microsoft Academic Search

Much work has been done to maximise the power extraction of wind turbine blades. However, small wind turbines are also required to be self starting and whilst blades designed for maximum power extraction can be optimised analytically, these blades often have poor starting performance. The numeric method of Differential Evolution is used here to maximise for both power and starting

M J Clifton-Smith; D H Wood

2007-01-01

303

Furling control for small wind turbine power regulation  

Microsoft Academic Search

In this paper, we analyze the steady-state performance and the impact on the power system of the dynamics of small wind turbines with power regulation based on furling control. Using an example of battery charging wind turbine system, we develop its model. In this model, we introduce damping as a component of the restraining moment. This is a novel concept

J. T. Bialasiewicz

2003-01-01

304

Optimization maintenance of wind turbines using Markov decision processes  

Microsoft Academic Search

As the wind power industry is getting more mature, and wind farms are taking their place as one of the mainstream options for new power generation, the demands for ensuring the wind turbines of reliable and economical operation are getting higher. Maintenance is indispensable to the core business objectives of the wind industry. Maintenance optimization is a means to determine

Yan-ru Wu; Hong-shan Zhao

2010-01-01

305

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

Microsoft Academic Search

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

Z. J. Meng; F. Xue

2010-01-01

306

Locations and attributes of wind turbines in New Mexico, 2011  

USGS Publications Warehouse

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

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

2013-01-01

307

Locations and attributes of wind turbines in Colorado, 2011  

USGS Publications Warehouse

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

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

2013-01-01

308

Can Wind Turbines be Bad for You? Alec N. Salt, Ph.D.  

E-print Network

Can Wind Turbines be Bad for You? Alec N. Salt, Ph.D. Department of Otolaryngology there happens to be a castle nearby). #12;Wind turbines haveWind turbines have been getting biggerbeen getting MegaWatts(MW) Total Installed Change by year 3% of US Energy Needs Wind turbines are "green" and areWind

Salt, Alec N.

309

innovati nNREL Innovations Contribute to an Award-Winning Small Wind Turbine  

E-print Network

innovati nNREL Innovations Contribute to an Award-Winning Small Wind Turbine The Skystream 3.7 wind (NREL) and Southwest Windpower, a commercially successful small wind turbine manufacturer. NREL drew blade design that makes the wind turbine more efficient and quieter than most. Small wind turbines

310

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

Microsoft Academic Search

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

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

2009-01-01

311

Spatial mapping and attribution of Wyoming wind turbines  

USGS Publications Warehouse

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

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

2010-01-01

312

Architecture Complexity and Energy Efficiency of Small Wind Turbines  

Microsoft Academic Search

The power characteristics of wind turbines are nonlinear. It is particularly true for vertical-axis turbines whose provided power is very sensitive to the load. Thus, controlling the operating point is essential to optimize the energetic behavior. Several control strategies (maximum power point tracking) can be used for the energy conversion. If the wind-turbine characteristic Cp(lambda) is supposed to be a

Adam Mirecki; Xavier Roboam; Frédéric Richardeau

2007-01-01

313

Along-wind response of a wind turbine tower with blade coupling subjected to rotationally sampled wind loading  

Microsoft Academic Search

This paper proposes an approach to investigate the along-wind forced vibration response of a wind turbine tower and rotating blades assembly subjected to rotationally sampled stationary wind loading. The wind turbine assembly consists of three rotating rotor blades connected to the top of a flexible annular tower, constituting a multi-body dynamic entity. The tower and rotating blades are each modelled

P. J. Murtagh; B. Basu; B. M. Broderick

2005-01-01

314

Measurements of mechanical torque acting on a model wind turbine  

NASA Astrophysics Data System (ADS)

A high precision torque converter is developed and calibrated to measure torques on model wind-turbine generators (small DC motor). By multiplying the measured torque and rotor angular velocity, a direct measurement of the extracted power from the wind turbine can be obtained. This direct method is more advantageous compared to the electrical power measured from the model generator, since it avoids contamination by internal friction, and electric and magnetic losses. The torque converter is mounted on a model wind turbine in a 3 by 3 array (3 rows by 3 columns) of wind turbines in the Corrsin wind tunnel. The power coefficients are obtained as a function of the tip speed ratio. Significant difference between the electrical and mechanical powers is observed, which emphasizes on the importance in using the direct mechanical power measurement. Also, the extracted power by the model turbine is found to be comparable with the power estimated from the kinetic energy flux measured using SPIV.

Kang, Hyung-Suk; Cal, Raul B.; Lebron-Bosques, Jose; Castillo, Luciano; Meneveau, Charles

2009-11-01

315

Understanding Trends in Wind Turbine Prices Over the Past Decade  

SciTech Connect

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

Bolinger, Mark; Wiser, Ryan

2011-10-26

316

Computational studies of horizontal axis wind turbines  

NASA Astrophysics Data System (ADS)

A numerical technique has been developed for efficiently simulating fully three-dimensional viscous fluid flow around horizontal axis wind turbines (HAWT) using a zonal approach. The flow field is viewed as a combination of viscous regions, inviscid regions and vortices. The method solves the costly unsteady Reynolds averaged Navier-Stokes (RANS) equations only in the viscous region around the turbine blades. It solves the full potential equation in the inviscid region where flow is irrotational and isentropic. The tip vortices are simulated using a Lagrangean approach, thus removing the need to accurately resolve them on a fine grid. The hybrid method is shown to provide good results with modest CPU resources. A full Navier-Stokes based methodology has also been developed for modeling wind turbines at high wind conditions where extensive stall may occur. An overset grid based version that can model rotor-tower interactions has been developed. Finally, a blade element theory based methodology has been developed for the purpose of developing improved tip loss models and stall delay models. The effects of turbulence are simulated using a zero equation eddy viscosity model, or a one equation Spalart-Allmaras model. Two transition models, one based on the Eppler's criterion, and the other based on Michel's criterion, have been developed and tested. The hybrid method has been extensively validated for axial wind conditions for three rotors---NREL Phase II, Phase III, and Phase VI configurations. A limited set of calculations has been done for rotors operating under yaw conditions. Preliminary simulations have also been carried out to assess the effects of the tower wake on the rotor. In most of these cases, satisfactory agreement has been obtained with measurements. Using the numerical results from present methodologies as a guide, Prandtl's tip loss model and Corrigan's stall delay model were correlated with present calculations. An improved tip loss model has been obtained. A correction to the Corrigan's stall delay model has also been developed. Incorporation of these corrections is shown to considerably improve power predictions, even when a very simple aerodynamic theory---blade element method with annular inflow---is used.

Xu, Guanpeng

317

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

USGS Publications Warehouse

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

Diffendorfer, Jay E.; Compton, Roger W.

2014-01-01

318

ERCOT's Dynamic Model of Wind Turbine Generators: Preprint  

SciTech Connect

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

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

2005-08-01

319

Power Performance Testing of Small Wind Turbines: Experiences and findings obtained testing the Bornay 1500 Inclin Neo Wind Turbine  

Microsoft Academic Search

Summary The new annex H of the standard IEC 61400-121 for Power Performance Testing of Small Wind Turbines (now in the approving process) was applied at CIEMAT test centre, on the characterization of the BORNAY 1500 Inclin Neo wind turbine. Results and findings obtained are presented.

Luis Arribas de Paz; Félix Avia; Luis Cano; Ignacio Cruz; Enrique Soria

320

Wind turbine reliability : a database and analysis approach.  

SciTech Connect

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

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

2008-02-01

321

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

Microsoft Academic Search

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

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

2004-01-01

322

Turbine Inflow Characterization at the National Wind Technology Center: Preprint  

SciTech Connect

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

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

2012-01-01

323

Contribution to a dynamic wind turbine model validation from a wind farm islanding experiment  

Microsoft Academic Search

Measurements from an islanding experiment on the Rejsby Hede wind farm, Denmark, are used for the validation of the dynamic model of grid-connected, stall-controlled wind turbines equipped with induction generators. The simulated results are found to be in good agreement with the measurements and possible discrepancies are explained. The work with the wind turbine model validation relates to the dynamic

J. K. Pedersen; K. O. Helgelsen-Pedersen; N. Kjølstad Poulsen; V. Akhmatov; A. Hejde Nielsen

2003-01-01

324

Electrical\\/mechanical options for variable speed wind turbines  

Microsoft Academic Search

The use of variable speed wind turbines, especially in large-scale utility electricity generating systems, offers a potential improvement in the cost effectiveness of wind energy systems. This paper presents a review of the potential options (including mechanical, electrical\\/mechanical, electrical, and electrical\\/power electronic) open for variable speed wind turbine design and gives some of the advantages and disadvantages of these design

J. F. Manwell; J. G. McGowan; B. H. Bailey

1991-01-01

325

The Selection of a Suitable Maintenance Strategy for Wind Turbines  

Microsoft Academic Search

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

Jesse A. Andrawus; Mohammed Kishk; Allan Adam

2006-01-01

326

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

E-print Network

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

Peinke, Joachim

327

Seismic analysis of wind turbines in the time domain  

NASA Astrophysics Data System (ADS)

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

Witcher, D.

2005-01-01

328

WIND TURBINE DRIVETRAIN TEST FACILITY DATA ACQUISITION SYSTEM  

SciTech Connect

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

Mcintosh, J.

2012-01-03

329

Simulation for Grid Connected Wind Turbines with Fluctuating  

NASA Astrophysics Data System (ADS)

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

Ye, Ying; Fu, Yang; Wei, Shurong

330

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

Microsoft Academic Search

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

I. Erlich; U. Bachmann

2005-01-01

331

State of the Art in Condition Monitoring in Wind Turbines Based on Embedded FBG Sensors  

Microsoft Academic Search

Wind energy is one of renewable energy sources, which is copiously available without any limitation. Wind turbines are used to tap the potential of wind energy. Thus, stability and reliability of wind turbine is critical to extract this maximum amount of energy from the wind. To keep the wind turbine in operation, implementation of condition monitoring is paramount. This paper,

Huang Xue-feng; Luo Dan; Wang Guan-qing; Ding Ning; Xu Jiang-rong; Liu Yan; Fan Hao

2010-01-01

332

Battery Voltage Stability Effects on Small Wind Turbine Energy Capture: Preprint  

Microsoft Academic Search

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 from pilot project performance monitoring has revealed shortcomings in wind turbine energy output up to 75% of expected due to

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

2002-01-01

333

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

Microsoft Academic Search

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

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

334

The Performance and Wind Tunnel Test of Aerofoils for Small Wind Turbine Generating Systems  

Microsoft Academic Search

The small scale wind turbines have been used as the stand alone power source for years. Particularly these days, there is an increasing demand for the small wind turbines, of the output below 1kW, as monuments and educational materials. It is recommended that wind turbines of a diameter under 1.0m must be the low blade tip speed ratio type, owing

Hideki Tokuyama; Izumi Ushiyama; Kazuichi Seki

2003-01-01

335

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

Microsoft Academic Search

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

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

2010-01-01

336

Fatigue reliability of wind turbine components  

SciTech Connect

Fatigue life estimates for wind turbine components can be extremely variable due to both inherently random and uncertain parameters. A structural reliability analysis is used to qualify the probability that the fatigue life will fall short of a selected target. Reliability analysis also produces measures of the relative importance of the various sources of uncertainty and the sensitivity of the reliability to each input parameter. The process of obtaining reliability estimates is briefly outlined. An example fatigue reliability calculation for a blade joint is formulated; reliability estimates, importance factors, and sensitivities are produced. Guidance in selecting distribution functions for the random variables used to model the random and uncertain parameters is also provided. 5 refs., 9 figs., 1 tab.

Veers, P.S.

1990-01-01

337

A fatigue approach to wind turbine control  

NASA Astrophysics Data System (ADS)

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

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

2007-07-01

338

Institutions Function and Failure Statistic and Analysis of Wind Turbine  

NASA Astrophysics Data System (ADS)

Recently,with install capacity of wind turbines increases continuously, the wind power consisting of operation,research on reliability,maintenance and rapair will be developed into a key point..Failure analysis can support operation,management of spare components and accessories in wind plants,maintenance and repair of wind turbines.In this paper,with the eye of wind plants'structure and function,statistic and analysis the common fault of each part of the plant,and then find out the faults law, faults cause and fault effect,from which put forward the corresponding measures.

yang, Ma; Chengbing, He; Xinxin, Feng

339

Panel resonant behavior of wind turbine blades.  

SciTech Connect

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

Paquette, Joshua A.; Griffith, Daniel Todd

2010-03-01

340

An overview of DOE`s wind turbine development programs  

SciTech Connect

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

Laxson, A; Dodge, D; Flowers, L [National Renewable Energy Lab., Golden, CO (United States); Loose, R; Goldman, P [Dept. of Energy, Washington, DC (United States)

1993-09-01

341

An overview of DOE's wind turbine development programs  

NASA Astrophysics Data System (ADS)

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

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

1993-09-01

342

St h ti d i l i fStochastic dynamic analysis of offshore wind turbines  

E-print Network

1 St h ti d i l i fStochastic dynamic analysis of offshore wind turbines ­ with emphasis on fatigue analysis of offshore bottom-fixed wind turbines · Modelling and dynamic analysis of floating wind turbines ­ Stochastic dynamic analysis of offshore wind turbines; mooring system for wave energy converters · 2010 8

Nørvåg, Kjetil

343

A High-Order Sliding Mode Observer for Sensorless Control ofDFIG-Based Wind Turbines  

E-print Network

A High-Order Sliding Mode Observer for Sensorless Control ofDFIG-Based Wind Turbines Mohamed control of a doubly-fed induction generator (DFIG) based wind turbine. The sensorless control scheme (generator and turbine). Simulations using the wind turbine simulator FAST on a 1.5- MW three-blade wind

Boyer, Edmond

344

www.cesos.ntnu.no Author Centre for Ships and Ocean Structures Offshore Wind Turbine Operation  

E-print Network

1 www.cesos.ntnu.no Author ­ Centre for Ships and Ocean Structures Offshore Wind Turbine Operation Structures Outline · Introduction · Wind Turbine Operational Conditions · Wind Turbine Operation under Atmospheric Icing · Wind Turbine Operation under Fault Condition · Conclusions www.cesos.ntnu.no M. Etemaddar

Nørvåg, Kjetil

345

EEMD-based wind turbine bearing failure detection using the generator stator current homopolar component  

E-print Network

EEMD-based wind turbine bearing failure detection using the generator stator current homopolar in wind turbine generators for stationary and non stationary cases. Keyword: Wind turbine, induction on the installed equipment because they are hardly accessible or even inaccessible [1]. 1.1. Wind turbine failure

Boyer, Edmond

346

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

E-print Network

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

Tedrake, Russ

347

TOWARDS LIFE-CYCLE MANAGEMENT OF WIND TURBINES BASED ON STRUCTURAL HEALTH MONITORING  

E-print Network

) strategies can enable wind turbine manufacturers, owners, and operators to precisely schedule maintenance, wind turbines, long-term monitoring, wind turbine operation and maintenance INTRODUCTION Renewable the road (EWEA 2010). Cost-efficient operation and maintenance of wind turbines is a primary concern

Stanford University

348

SYSTEMIC ASSESSMENT AND ANALYSIS OF FACTORS AFFECT THE RELIABILITY OF A WIND TURBINE  

Microsoft Academic Search

Nowadays, the availability of wind turbines usually approaches the 98%. The objective is to increase the turbines availability, by improving the wind turbine reliability especially for offshore plants. The wind turbines reliability is a pivotal factor in the successfully function of a wind power plant. High reliability can be achieved by understanding and minimizing the failures of the system. Maintenance

Pantelis N. Botsaris; D. Pitsa

2012-01-01

349

Design and construction of a simple blade pitch measurement system for small wind turbines  

Microsoft Academic Search

For small wind turbines to be reliable they must have in place good mechanisms to protect themselves against very high winds or sudden removal of load. One common protection method in small wind turbines is that of blade feathering. It is important that the blade feathering mechanism of a small wind turbine is tested before the turbine is installed in

Jonathan Whale

2009-01-01

350

Quantifying the hurricane risk to offshore wind turbines  

PubMed Central

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

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

2012-01-01

351

Voltage analysis of distribution systems with DFIG wind turbines  

Microsoft Academic Search

Wind energy is becoming the most viable renewable energy source mainly because of the growing concerns over carbon emissions and uncertainties in fossil fuel supplies and the government policy impetus. The increasing penetration of wind power in distribution systems may significantly affect voltage stability of the systems, particularly during wind turbine cut-in and cut-off disturbances. Currently, doubly fed induction generator

Baohua Dong; Sohrab Asgarpoor; Wei Qiao

2009-01-01

352

Active Power Control Strategies of DFIG Wind Turbines  

Microsoft Academic Search

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

Noël A. Janssens; Guillaume Lambin; Nicolas Bragard

2007-01-01

353

Selection of Wind Turbine Blade Materials for Fatigue Resistance  

E-print Network

Selection of Wind Turbine Blade Materials for Fatigue Resistance John Mandell Montana StateE glass and similar compositions · High Performance Glass (WindStrand) C b· Carbon #12;Tensile Fatigue E Gl (2 f b i )E-Glass (2 fabrics), WindStrand, Carbon ; Epoxy Resins; Stress Based (top) and Stress

354

Seabed instability simplified model and application in offshore wind turbine  

Microsoft Academic Search

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

Zhang Yong-li; Li Jie

2009-01-01

355

Small Wind Turbine power curves obtained in laboratory  

Microsoft Academic Search

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

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

2010-01-01

356

High temperature co-axial winding transformers  

NASA Technical Reports Server (NTRS)

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

Divan, Deepakraj M.; Novotny, Donald W.

1993-01-01

357

Locations and attributes of wind turbines in Colorado, 2009  

USGS Publications Warehouse

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

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

2011-01-01

358

Locations and attributes of wind turbines in New Mexico, 2009  

USGS Publications Warehouse

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

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

2011-01-01

359

Mars Technologies Spawn Durable Wind Turbines  

NASA Technical Reports Server (NTRS)

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

Bubenheim, David L.

2013-01-01

360

Detection of wind turbine blades damage by spectrum-recognition using gaussian wavelet-entropy  

Microsoft Academic Search

In this paper, a complex continuous wavelet transform (CWT)-based entropy method is proposed to enhance the damage-detection capability of wind turbine blades. By embedding the time-frequency localization features in wavelets, wavelet entropy of acquired signals can be readily computed. This approach can form a quantitative index systematically to detect the damage of blades, anticipating formulating a forewarning mechanism for wind

C. S. Tsai; C. T. Hsieh; K. L. Lew

2009-01-01

361

Midwest Consortium for Wind Turbine Reliability and Optimization  

SciTech Connect

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

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

2012-05-11

362

Wind turbine blade health monitoring using acoustic beamforming techniques.  

PubMed

Wind turbines operate autonomously and can possess reliability issues attributed to manufacturing defects, fatigue failure, or extreme weather events. In particular, wind turbine blades can suffer from leading and trailing edge splits, holes, or cracks that can lead to blade failure and loss of energy revenue generation. In order to help identify damage, several approaches have been used to detect cracks in wind turbine blades; however, most of these methods require transducers to be mounted on the turbine blades, are not effective, or require visual inspection. This paper will propose a new methodology of the wind turbine non-contact health monitoring using the acoustic beamforming techniques. By mounting an audio speaker inside of the wind turbine blade, it may be possible to detect cracks or damage within the structure by observing the sound radiated from the blade. Within this work, a phased array beamforming technique is used to process acoustic data for the purpose of damage detection. Several algorithms are evaluated including the CLEAN-based Subtraction of Point spread function from a Reference (CLSPR) on a composite panel and a section of a wind turbine blade in the laboratory. PMID:25235971

Aizawa, Kai; Niezrecki, Christopher

2014-04-01

363

Dissipation of turbulence in the wake of a wind turbine  

NASA Astrophysics Data System (ADS)

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

Lundquist, J. K.; Bariteau, L.

2013-12-01

364

Yaw dynamics of horizontal axis wind turbines  

SciTech Connect

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

Hansen, A.C. (Utah Univ., Salt Lake City, UT (United States))

1992-05-01

365

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

NASA Technical Reports Server (NTRS)

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

1984-01-01

366

Assessment Parameters and Matching between the Sites and Wind Turbines  

NASA Astrophysics Data System (ADS)

The objective of this paper is to introduce the assessment parameters of the wind energy production of sites and pairing between the sites and wind turbines. The exploration is made with the wind data gathered at 10 m high is based on the atlas of the wind of Algeria established by the National office of the Meteorology runs 37 stations of measures. The data is used for a feasibility analysis of optimum future utilization of Wind generator potentiality in five promising sites covering a part of landscape types and regions in Algeria. Detailed technical assessment for the ten most promising potential wind sites was made using the capacity factor and the site effectiveness approach. The investigation was performed assuming several models of small, medium and big size wind machines representing different ranges of characteristic speeds and rated power suitable for water pumping and electric supply. The results show that small wind turbines could be installed in some coast region and medium wind turbines could be installed in the high plateau and some desert regions and utilized for water supply and electrical power generation, the sites having an important wind deposit, in high plateau we find Tiaret site's but in the desert there is some sites for example Adrar, Timimoun and In Amenas, in these sites could be installed a medium and big size wind turbines.

Chermitti, A.; Bencherif, M.; Nakoul, Z.; Bibitriki, N.; Benyoucef, B.

367

Comparison of three methods for wind turbine capacity factor estimation.  

PubMed

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

Ditkovich, Y; Kuperman, A

2014-01-01

368

Comparison of Three Methods for Wind Turbine Capacity Factor Estimation  

PubMed Central

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

Ditkovich, Y.; Kuperman, A.

2014-01-01

369

Demonstration of the Ability of RCAS to Model Wind Turbines  

SciTech Connect

In recent years, the wind industry has sponsored the development, verification, and validation of comprehensive aeroelastic simulators, which are used for wind turbine design, certification, and research. Unfortunately, as wind turbines continue to grow in size and sometimes exhibit unconventional design characteristics, the existing codes do not always support the additional analysis features required for proper design. The development history, functionality, and advanced nature of RCAS (Rotorcraft Comprehensive Analysis System) make this code a sensible option. RCAS is an aeroelastic simulator developed over a 4-year cooperative effort amongst the U.S. Army's Aeroflightdynamics Directorate, Advanced Rotorcraft Technology (ART), Inc., and the helicopter industry. As its name suggests, RCAS was created for the rotorcraft industry but developed as a general purpose code for modeling the aerodynamic and structural response of any system with rotating and nonrotating subsystems (such as wind turbines). To demonstrate that RCAS can analyze wind turbines, models of a conventional, 1.5-MW, 3-bladed, upwind, horizontal axis wind turbine (HAWT) are created in RCAS and wind turbine analysis codes FAST (Fatigue, Aerodynamics, Structures, and Turbulence) and ADAMS (Automatic Dynamic Analysis of Mechanical Systems). Using these models, a side-by-side comparison of structural response predictions is performed under several test scenarios.

Jonkman, J.; Cotrell, J.

2003-08-01

370

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

NASA Astrophysics Data System (ADS)

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

Emre Yilmaz, Ali; Meyers, Johan

2014-06-01

371

Performance Study and Optimization of the Zephergy Wind Turbine  

E-print Network

There are many problems associated with small wind turbines, such as small Reynolds number and poor starting performance, that make them much more expensive than the large ones per unit power. New technologies are needed to improve the quality...

Soodavi, Moein

2013-12-04

372

Load Alleviation on Wind Turbine Blades using Variable Airfoil Geometry  

E-print Network

Load Alleviation on Wind Turbine Blades using Variable Airfoil Geometry Peter Bjørn Andersen, Mac deflection angle of the airfoil camberline correlates well with the relative flapwise deflection of the blade

373

The General Electric MOD-1 wind turbine generator program  

NASA Technical Reports Server (NTRS)

The design, fabrication, installation and checkout of MOD-1, a megawatt class wind turbine generator which generates utility grade electrical power, is described. A MOD-1/MOD-1A tradeoff study is discussed.

Poor, R. H.; Hobbs, R. B.

1979-01-01

374

Vertical axis wind turbine with continuous blade angle adjustment  

E-print Network

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

Weiss, Samuel Bruce

2010-01-01

375

Intimate Emptiness: The Flint Hills Wind Turbine Controversy  

E-print Network

ABSTRACT Howard Graham, Master of Arts American Studies, July 2008 University of Kansas This study examines the political and social controversy surrounding the proposed introduction of industrial scale wind turbines, roughly, those over 120 feet...

Graham, Howard Russell

2008-07-28

376

Variable speed generator technology options for wind turbine generators  

NASA Technical Reports Server (NTRS)

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

Lipo, T. A.

1995-01-01

377

Design of wind turbines with Ultra-High Performance Concrete  

E-print Network

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

Jammes, François-Xavier

2009-01-01

378

Development of a New Procedure for Reliability Modeling of Wind Turbine Generators  

Microsoft Academic Search

A method for determining the impact of wind generation on system reliability is developed. This method combines the effects of wind turbine forced outage rates and varying power output due to wind speed variations. Since individual wind turbines on a windfarm all have an output related to wind speed, each turbine's output cannot be assumed to be independent random variables.

Paul Giorsetto; Kent F. Utsurogi

1983-01-01

379

Impact of DFIG wind turbines on transient stability of power systems a review  

E-print Network

Impact of DFIG wind turbines on transient stability of power systems ­ a review Authors Na Abstract of wind farms are using variable speed wind turbines equipped with doubly-fed induction generators (DFIG) due to their advantages over other wind turbine generators. Therefore, the analysis of wind power

Pota, Himanshu Roy

380

Analysis and Comparison of Test Results from the Small Wind Research Turbine Test Project: Preprint  

Microsoft Academic Search

Most small wind turbines furl (yaw or tilt out of the wind) as a means of limiting power and rotor speeds in high winds. The Small Wind Research Turbine (SWRT) testing project was initiated in 2003 with the goal of better characterizing both small wind turbine loads (including thrust) and dynamic behavior, specifically as they relate to furling. The main

D. Corbus; D. Prascher

2004-01-01

381

Constructing a plastic bottle wind turbine as a practical aid for learning about using wind energy to generate electricity  

Microsoft Academic Search

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

S J Appleyard

2009-01-01

382

Constructing a plastic bottle wind turbine as a practical aid for learning about using wind energy to generate electricity  

Microsoft Academic Search

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

S. J. Appleyard

2009-01-01

383

Performance optimization of a dual-rotor wind turbine system  

Microsoft Academic Search

We are building an efficient and smart wind turbine system. The significant features of this turbine are its dual rotor blade system which is positioned horizontally at upwind and downwind locations, its drive train which is installed horizontally inside the tower with a new efficient induction generator, and its control and safety systems. The project focuses mainly on the methodology

Riadh W. Y. Habash; Voicu Groza; Pierre Guillemette

2010-01-01

384

Simulating dynamic interactions of grid-linked wind turbines  

Microsoft Academic Search

Models for dynamic interaction of wind turbine generators (WTGs) on electric utility networks have been suggested, but only a few publications have addressed the aggregation of hundreds of turbine generators. This topic has a significant impact on studies related to power system dynamics, because it helps reduce system complexity and computation cost. This article features a study that set out

R. Chedidl; N. LaWhite; M. Ilic

1994-01-01

385

CFD simulation of turbulent airflow around wind turbine airfoils  

NASA Astrophysics Data System (ADS)

The airflow around wind turbines has proved to be a difficult problem to approach by means of today's Computational Fluid Dynamics (CFD) codes. One reason for this difficulty lies within the stall characteristics of turbine airfoils. For the purposes of this research, the popular commercial CFD code, FLUENT was employed to facilitate the understanding of airflow around wind turbines through the study of various turbulence models. Parallel processing was employed to enhance computational performance as well as lower simulation times. The system used for simulation is the National Renewable Energy Laboratory (NREL) Phase VI Wind Turbine. The coefficients of pressure for the airfoil were extracted from the simulated data and compared against data obtained during the NREL Phase VI Wind Turbine data campaign. Since power is a driving factor of the design of wind turbine blades, the aspect of power was also examined and compared. After the completion of the baseline study, a parametric study was carried out to examine the effects of rotor speed downstream of the turbine blades.

Halbrooks, David N.

386

Overview of and trends in wind turbine generator systems  

Microsoft Academic Search

This paper gives an overview of wind turbine generator systems and describes some trends. Around 1998, many wind turbine manufacturers changed from constant speed systems to variable speed with doubly-fed induction generators. Since around 2005, they have come with a number of alternative generators systems, mainly to comply with grid requirements as grid-fault ride-through. Most alternatives have brushless generators and

Henk Polinder

2011-01-01

387

Data Analytics Methods in Wind Turbine Design and Operations  

E-print Network

of physical changes in wind turbines including intentional retro t, natural degradation, or system faults. It is important to study e ective methods that can detect the occurrence of anomalies. 9 I.3. Research objective and outline Due to uncertainty... of physical changes in wind turbines including intentional retro t, natural degradation, or system faults. It is important to study e ective methods that can detect the occurrence of anomalies. 9 I.3. Research objective and outline Due to uncertainty...

Lee, Giwhyun

2013-05-22

388

Evaluation of the vertical axis wind turbine at DREO  

Microsoft Academic Search

A Vertical Axis Wind Turbine-Battery Storage System was installed at the Defence Research Establishment Ottawa (DREO) in December 1975 and was operated for three years. The system was instrumented to control and monitor its operation and performance. This report deals with an evaluation study of a Vertical Axis Wind Turbine-Battery Storage System for a low-power unattended power source. The System's

H. R. Braun; D. J. Bristow; S. J. Wake

1980-01-01

389

Active and Passive Lift Force Augmentation Techniques on Wind Turbines  

NASA Astrophysics Data System (ADS)

The paper presents a short review of active and passive lift force augmentation concepts for wind turbines. The few models presented were analyzed using CFD to determine their potential in terms of improved performance of wind turbines. There will also be presented and computational aspects related to modeling active and passive control systems. Numerical simulations are based on RANS (Reynolds averaged Navier-Stokes) equations model supplemented with a suitable turbulence model; in our case turbulence models used were k-? and k-? SST.

Frunzulic?, F.; Dumitrescu, H.; Mahu, R.; Preotu, O.

2011-09-01

390

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

E-print Network

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

Reddy, Sivananda Kumjula

2005-01-01

391

Wind turbine blade damage detection using an active sensing approach  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

392

Atmospheric and Wake Turbulence Impacts on Wind Turbine Fatigue Loadings  

SciTech Connect

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

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

2012-01-01

393

Nonlinear control with wind estimation of a DFIG variable speed wind turbine for power capture optimization  

Microsoft Academic Search

A cascaded nonlinear controller is designed for a variable speed wind turbine equipped with a Doubly Fed Induction Generator (DFIG). The main objective of the controller is wind energy capture optimization while avoiding strong transients in the turbine components and specially in the drive train. The inner loop controller ensures an efficient tracking of both generator torque and stator flux,

B. Boukhezzar; H. Siguerdidjane

2009-01-01

394

Selection of Suitable Wind Turbine for Wind Farm Candidate Site Narakkalliya, Kalpitiya Peninsula, Sri Lanka  

Microsoft Academic Search

Out of the candidate sites feasible to construct utility scale wind farms in Sri Lanka, Kalpitiya peninsula is the ideal site. Wind Turbine NM 54\\/950 of NEG Micon AS of Denmark best suits site characteristics and could be used in first large scale wind farm in Sri Lanka. If the wind farm is to be constructed based on Build, Own

395

Reactive power optimization control of wind farms with fixed-speed wind turbine generators  

Microsoft Academic Search

As the level of wind power penetration into the grid increases, reactive power control will become more critical for wind farms with fixed-speed wind turbine generators. Capacitor banks are used for reactive power compensation in wind power plant (WPP). This paper focuses on our effort to develop a method to determine the number, sizes and control strategy of capacitor banks.

Xunwen Su; Zengqiang Mi; Xingjie Liu; Tao Wu

2008-01-01

396

LiDAR observations of offshore winds at future wind turbine operating heights  

E-print Network

LiDAR observations of offshore winds at future wind turbine operating heights Alfredo Peña1 , Sven: Charnock, LiDAR, Marine boundary layer, Offshore, Surface layer, Wind profile. 1 Introduction There is to observe accurately the wind speed as shown by [6] over land and [7] and [2] over sea. In particular, LiDAR

397

Large band simulation of the wind speed for real time wind turbine simulators  

Microsoft Academic Search

In this paper, the authors propose two modeling procedures for wind speed simulation. These procedures could be implemented on the structure of a wind turbine simulator during studies concerning stand-alone or hybrid wind systems. The evolution of a horizontal wind speed has been synthesized taking into account two components. The medium- and long-term component is described by a power spectrum

Cristian Nichita; Dragos Luca; Brayima Dakyo; Emil Ceanga

2002-01-01

398

Comparative study of the behavior of wind-turbines in a wind farm  

Microsoft Academic Search

The Sotavento wind farm is an experimental wind farm which has different types of wind turbines. It is located in an area whose topography is moderately complex, and where wake effects can be significant. One of the objectives of Sotavento wind farm is to compare the performances of the different machines; particularly regarding power production, maintenance and failures. However, because

Emilio Migoya; Antonio Crespo; Javier García; Fermín Moreno; Fernando Manuel; Ángel Jiménez; Alexandre Costa

2007-01-01

399

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

Microsoft Academic Search

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

A. Dragomirescu

2011-01-01

400

Strategies for Refining IEC 61400-2: Wind Turbine Generator Systems - Part 2: Safety of Small Wind Turbines: Preprint  

Microsoft Academic Search

This paper provides a status of the changes currently being made by IEC Maintenance Team 02 (MT02) to the existing IEC 61400-2 ''Safety of small wind turbines.'' In relation to the work done by IEC MT02, work has been done by NREL and Windward Engineering under the DOE\\/NREL Small Wind Turbine (SWT) Project. Aeroelastic models were built and measurements taken

J. J. D. van Dam; T. L. Forsyth; A. C. Hansen

2001-01-01

401

Testing basic performance of a very small wind turbine designed for multi-purposes  

Microsoft Academic Search

A very small wind turbine system for multi-purposes was developed and its performance was reported in this paper. The rotor diameter of the turbine is 500mm. The tests of the energy output, turbine speed, power coefficient, and torque of turbine were carried out for a wide rage of free stream velocity. The flow around the wind turbine and the influence

Hiroyuki Hirahara; M. Zakir Hossain; Masaaki Kawahashi; Yoshitami Nonomura

2005-01-01

402

Defining the normal turbine inflow within a wind park environment  

SciTech Connect

This brief paper discusses factors that must be considered when defining the {open_quotes}normal{close_quotes} (as opposed to {open_quotes}extreme{close_quotes}) loading conditions seen in wind turbines operating within a wind park environment. The author defines the {open_quotes}normal{close_quotes} conditions to include fatigue damage accumulation as a result of: (1) start/stop cycles, (2) emergency shutdowns, and (3) the turbulence environment associated with site and turbine location. He also interprets {open_quotes}extreme{close_quotes} loading conditions to include those events that can challenge the survivability of the turbine.

Kelley, N.D.

1993-06-01

403

Defining the normal turbine inflow within a wind park environment  

SciTech Connect

This brief paper discusses factors that must be considered when defining the [open quotes]normal[close quotes] (as opposed to [open quotes]extreme[close quotes]) loading conditions seen in wind turbines operating within a wind park environment. The author defines the [open quotes]normal[close quotes] conditions to include fatigue damage accumulation as a result of: (1) start/stop cycles, (2) emergency shutdowns, and (3) the turbulence environment associated with site and turbine location. He also interprets [open quotes]extreme[close quotes] loading conditions to include those events that can challenge the survivability of the turbine.

Kelley, N.D.

1993-06-01

404

Coupled Dynamic Modeling of Floating Wind Turbine Systems: Preprint  

SciTech Connect

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

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

2006-03-01

405

Nonlinear parametric instability of wind turbine wings  

NASA Astrophysics Data System (ADS)

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

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

2007-01-01

406

Study of composite wind turbine spars  

NASA Astrophysics Data System (ADS)

This report presents a theoretical, numerical and experimental study of composite wind turbine spars under bending loads. Spars were made from commercially available glass/ carbon fiber material. The spars were composed of uniaxial (0°) flanges and biaxial (+/-45°) shear webs. Items of particular study were co-block polymer additives in vinyl ester resins, a presumably new spar design, and using carbon fiber pultrusions for spar caps (flanges). Composites are very strong and thus tend to be thin, which exacerbates the problem of buckling. Further, fibers also buckle at the micro level, leading to lower effective compression strength than tensile strength of a composite. Many structures tend to buckle in out of plane direction which can cause early and abrupt failure. A 3-point bend test rig was manufactured in-house for experimentally testing composite spars. The experiments indicated abrupt failure without any sign or other form of damage. Limited number of spars was made with slightly different construction. All spars were subjected to same testing environment. Finite element analyses were performed in order to shed light on the failure mechanisms leading to catastrophic failure. The FE code Ansys was used for the analyses. 3D models were developed, loads were applied, and linear elastic static as well as buckling analyses were performed. The results obtained from analysis were in reasonable agreement with the experimental tests.

Zafar, Syed Shahrukh

407

The History and State of the Art of Variable-Speed Wind Turbine Technology  

Microsoft Academic Search

Early wind turbines used for performing mechanical work (pumping, grinding and cutting) optimized aerodynamics by being allowed to run at variable speed. Some of the earliest DC electric wind turbines were allowed to run at variable speed. With the advent of grid-connected AC turbines, rotational speeds were limited in order to control the wind turbine AC frequency output to equal

P. W. Carlin; A. S. Laxson; E. B. Muljadi

2003-01-01

408

The inception of OMA in the development of modal testing technology for wind turbines  

Microsoft Academic Search

Wind turbines are immense, flexible structures with aerodynamic forces acting on the rotating blades at harmonics of the turbine rotational frequency. These harmonics are comparable to the modal frequencies of the structure. Predicting and experimentally measuring the modal frequencies of wind turbines have been important to their successful design and operation. Performing modal tests on wind turbine structures over 100

Thomas G. Carne; George H. James

2010-01-01

409

The inception of OMA in the development of modal testing technology for wind turbines  

Microsoft Academic Search

Wind turbines are immense, flexible structures with aerodynamic forces acting on the rotating blades at harmonics of the turbine rotational frequency. These harmonics are comparable to the modal frequencies of the structure. Predicting and experimentally measuring the modal frequencies of wind turbines have been important to their successful design and operation. Performing modal tests on wind turbine structures over 100m

Thomas G. Carne; George H. James III

2010-01-01

410

Real-Time Wind Turbine Emulator Suitable for Power Quality and Dynamic Control Studies  

E-print Network

1 Real-Time Wind Turbine Emulator Suitable for Power Quality and Dynamic Control Studies Dale S. L. Dolan, Student Member, IEEE, P. W. Lehn, Member IEEE Abstract-- Wind turbines are increasingly becoming-time Wind Turbine Emulator, which emulates the dynamic torque produced by an actual turbine has been

Lehn, Peter W.

411

RIS0-M-2242 ANALYSIS OF DATA FROM THE GEDSER WIND TURBINE 1977-1979  

E-print Network

RIS0-M-2242 ANALYSIS OF DATA FROM THE GEDSER WIND TURBINE 1977-1979 P. Lundsager, S. Frandsen, C on the data from the Gedser wind turbine measurements, made during 1977 to 1979. The report contains chap turbine with modern Danish, Swedish and American experimental wind turbines, based on published data. UDC

412

Energy Based Methods in Wind Turbine Control CeSOS Highlights and AMOS Visions  

E-print Network

Energy Based Methods in Wind Turbine Control CeSOS Highlights and AMOS Visions Morten D. Pedersen 1 / 26 #12;This talk 1 Background 2 Understanding the Wind Turbine 3 Nonlinear Turbine Modeling 4;Background The Problem Previously stable wind turbine systems began exhibiting resonant behavior when put

Nørvåg, Kjetil

413

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

SciTech Connect

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

GE Wind Energy, LLC

2006-05-01

414

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

SciTech Connect

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

Hughes, P.; Sherwin, R. [Atlantic Orient Corp., Norwich, VT (United States)] [Atlantic Orient Corp., Norwich, VT (United States)

1994-08-01

415

Advanced wind turbine design studies: Advanced conceptual study  

NASA Astrophysics Data System (ADS)

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

Hughes, P.; Sherwin, R.

1994-08-01

416

Wind Turbine Blade Design System - Aerodynamic and Structural Analysis  

NASA Astrophysics Data System (ADS)

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

Dey, Soumitr

417

Characterizing wind turbine system response to lightning activity  

SciTech Connect

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

McNiff, B.; LaWhite, N. [McNiff Light Industry, Harborside, ME (United States); Muljadi, E. [National Renewable Energy Lab., Golden, CO (United States)

1998-07-01

418

LES investigation of turbine spacing effects in wind farms  

NASA Astrophysics Data System (ADS)

We study turbine spacing and layout effects in large wind farms using large-eddy simulation (LES) with the actuator disk model to represent individual turbines. The actuator disk model is implemented in our second-order accurate immersed boundary finite-difference solver using the discrete delta functions to interpolate the velocities on the disk and distribute the body forces to the surrounding fluid points. For aligned wind farms, the effects of the streamwise and spanwise spacings on the extracted power and turbulence intensities in the vicinity of the turbines are systematically studied. A model for the effective roughness length is also developed based on the present numerical results. As part of our future work, the effect of turbine spacing in staggered wind farms will be investigated.

Yang, Xiaolei; Sotiropoulos, Fotis

2011-11-01

419

Electrical generation using a vertical-axis wind turbine  

SciTech Connect

Traditionally, windmills have been of the propeller or multiblade types, both of which have their rotational axis parallel to the flow of the wind. A vertical-axis wind turbine has its rotational axis perpendicular to the flow of wind and requires no orientation to keep the rotor in the windstream. The vertical-axis wind turbine operates on the same principle as an airfoil and produces lift and drag as any airfoil. A newly designed 100-kW vertical-axis wind turbine has been operated for one year at the USDA Conservation and Production Research Laboratory, Bushland, TX. The turbine has an induction generator and supplies power to a sprinkler irrigation system with excess power being sold to the electric utility. The turbine begins producing power at 5.5 m/s windspeed and reaches its rated output of 100-kW at 15 m/s. The unit has obtained a peak efficiency of 48% at a windspeed of 8 m/s or 81% of theoretical maximum. Using 17 years of windspeed data from the National Weather Service, the annual energy output is estimated at 200,000 kWh. The unit has experienced several operational problems during its initial testing. Guy cables were enlarged to provide greater stiffness to reduce blade stress levels, lightning shorted the main contactor, and the brake system required a complete redesign and modification. The turbine was operational about 60% of the time.

Clark, R.N.

1982-12-01

420

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

SciTech Connect

Average or expectation values for annual power of a wind turbine in a Rayleigh wind regime are calculated and plotted as a function of cut-out wind speed. This wind speed is expressed in multiples of the annual average wind speed at the turbine installation site. To provide a common basis for comparison of all real and imagined turbines, the Rayleigh-Betz wind machine is postulated. This machine is an ideal wind machine operating with the ideal Betz power coefficient of 0.593 in a Rayleigh probability wind regime. All other average annual powers are expressed in fractions of that power. Cases considered include: (1) an ideal machine with finite power and finite cutout speed, (2) real machines operating in variable speed mode at their maximum power coefficient, and (3) real machines operating at constant speed.

Carlin, P.W.

1996-12-01

421

Potential order-of-magnitude enhancement of wind farm power density via counter-rotating vertical-axis wind turbine arrays  

Microsoft Academic Search

Modern wind farms comprised of horizontal-axis wind turbines (HAWTs) require significant land resources to separate each wind turbine from the adjacent turbine wakes. This aerodynamic constraint limits the amount of power that can be extracted from a given wind farm footprint. The resulting inefficiency of HAWT farms is currently compensated by using taller wind turbines to access greater wind resources

John O. Dabiri

2010-01-01

422

Potential order-of-magnitude enhancement of wind farm power density via counter-rotating vertical-axis wind turbine arrays  

Microsoft Academic Search

Modern wind farms comprised of horizontal-axis wind turbines (HAWTs) require significant land resources to separate each wind turbine from the adjacent turbine wakes. This aerodynamic constraint limits the amount of power that can be extracted from a given wind farm footprint. The resulting inefficiency of HAWT farms is currently compensated by using taller wind turbines to access greater wind resources

John O. Dabiri

2011-01-01

423

Background and system description of the Mod 1 wind turbine generator  

NASA Technical Reports Server (NTRS)

The Mod-1 wind turbine considered is a large utility-class machine, operating in the high wind regime, which has the potential for generation of utility grade power at costs competitive with other alternative energy sources. A Mod-1 wind turbine generator (WTG) description is presented, taking into account the two variable-pitch steel blades of the rotor, the drive train, power generation/control, the Nacelle structure, and the yaw drive. The major surface elements of the WTG are the ground enclosure, the back-up battery system, the step-up transformer, elements of the data system, cabling, area lighting, and tower foundation. The final system weight (rotor, Nacelle, and tower) is expected to be about 650,000 pounds. The WTG will be capable of delivering 1800 kW to the utility grid in a wind-speed above 25 mph.

Ernst, E. H.

1978-01-01

424

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

SciTech Connect

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

Churchfield, M. J.

2013-08-01

425

Predictive diagnosis for offshore wind turbines using holistic condition monitoring  

Microsoft Academic Search

This paper presents the role of SeeByte's RECOVERY system within the wind energy industry, with specific focus on an offshore scenario. The current generation of condition monitoring systems (CMS) in relation to wind energy are generally provided by turbine manufacturers, or have been adapted from other industries. These systems have a propensity to focus explicitly on individual parts of the

E. Miguela?ñez

2010-01-01

426

Frequency Domain Load Calculation for Offshore Wind Turbines (TURBU Offshore)  

Microsoft Academic Search

The design of offshore wind turbines requires to assess a huge amount of different sea-states and wind conditions. Therefor the calculational efficiency of a comb ined time\\/frequency domain approach is attractive. This was the reason for the development of the frequency domain tool TURBU Offshore. In addition, such a tool is very feasible for parameter studies; the dynamics of large

T. G. van Engelen

427

Wind-turbine project tests out an alternative energy source  

Microsoft Academic Search

The Bureau of Reclamation has proposed a project to be constructed at Medicine Bow, Wyoming that will integrate utility-sized wind turbines into an already existing hydroelectric system. Despite the final positive feasibility report and environmental assessment of the project, several issues that remain undecided are discussed. The construction of wind-energy fields could potentially provide as much as 10% of the

2009-01-01

428

Load response of horizontal-axis wind turbines to turbulence  

Microsoft Academic Search

A structural and aerodynamic model of a three-bladed rigid-hub wind turbine is described. The model includes four structural degrees of freedom; one for each blade in flapping, and tower translation. The aerodynamic model includes the effects of wind turbulence as well as the unsteady aerodynamic effects caused by the airfoil shed and trailing wakes. A separate code developed at the

R. E. Wilson; S. N. Walker; J. R. Hartin; T. L. Weber

1990-01-01

429

Pitch-controlled variable-speed wind turbine generation  

Microsoft Academic Search

This paper covers the operation of variable-speed wind turbines with pitch control. The system the authors considered is controlled to generate maximum energy while minimizing loads. The maximization of energy was only carried out on a static basis and only drive train loads were considered as a constraint. In low to medium wind speeds, the generator and the power converter

Eduard Muljadi; C. P. Butterfield

2001-01-01

430

On the Modelling of a Floating Offshore Wind Turbine  

Microsoft Academic Search

The location of wind turbines on floating structures offshore would allow an immense resource to be tapped without the drawbacks large developments can have on public opinion. There are, however, potentially significant technical and cost drawbacks. This article describes the theory and results of research work aimed at developing analytical tools for evaluating the performance of floating offshore wind farms.

Andrew R. Henderson; Minoo H. Patel

2003-01-01

431

Innovative Design Approaches for Large Wind Turbine Blades  

Microsoft Academic Search

The primary goal of the WindPACT Blade System Design Study (BSDS) was investigation and evaluation of design and manufacturing issues for wind turbine blades in the one to ten megawatt size range. The initial project task was to assess the fundamental physical and manufacturing issues that govern and constrain large blades and entails three basic elements: (1) a parametric scaling

THOMAS D

2003-01-01

432

Seismic analysis of wind turbines in the time domain  

Microsoft Academic Search

The analysis of wind turbine loading associated with earthquakes is clearly important when designing for and assessing the feasibility of wind farms in seismically active regions. The approach taken for such analysis is generally based on codified methods which have been developed for the assessment of seismic loads acting on buildings. These methods are not able to deal properly with

D. Witcher

2005-01-01

433

Maintenance strategies for deep-sea offshore wind turbines  

Microsoft Academic Search

Purpose – The objective of this paper is to outline a framework that guides the development of sound maintenance strategies and policies for deep-sea offshore wind turbines. Design\\/methodology\\/approach – An important challenge with offshore wind energy production is to reduce the high operation and maintenance costs. To decrease complexity, and structure the maintenance strategy developing process, systems engineering principles are

Ingrid Bouwer Utne

2010-01-01

434

SPECIFICATIONS FOR SMALL WIND TURBINES FOR AUTONOMOUS ENERGY SYSTEMS  

Microsoft Academic Search

For a wide implementation of Wind Energy Conversion Systems (WECS) in island areas, it is imperative to produce a simple and effective design concept, to enhance their robustness and to minimise their cost. It is evident that the experience coming from the large Wind Turbines technology cannot be applied to the isolated medium and small systems. This is mainly because

C. G. Condaxakis; D. G. Christakis; C. A. Tsambazis; T. A. Chortatsos

435

EVALUATION OF HAND LAY-UP AND RESIN TRANSFER MOLDING IN COMPOSITE WIND TURBINE BLADE MANUFACTURING  

E-print Network

EVALUATION OF HAND LAY-UP AND RESIN TRANSFER MOLDING IN COMPOSITE WIND TURBINE BLADE MANUFACTURING..........................................................................................................1 Hand Lay-up in Turbine Blade Fabrication

436

Causes of bat fatalities at wind turbines: Hypotheses and predictions  

USGS Publications Warehouse

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

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

2009-01-01

437

Fuzzy regulator design for wind turbine yaw control.  

PubMed

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

438

STRUCTURAL HEALTH MONITORING OF THE SUPPORT STRUCTURE OF WIND TURBINE USING WIRELESS SENSING SYSTEM  

E-print Network

practical alternative today. Currently, through the development of wind energy, the number of wind turbineSTRUCTURAL HEALTH MONITORING OF THE SUPPORT STRUCTURE OF WIND TURBINE USING WIRELESS SENSING SYSTEM, Taiwan kclu@narlabs.org.tw ABSTRACT The wind turbine heavily depends on the success of the support

Boyer, Edmond

439

Voltage recovery of grid-connected wind turbines with DFIG after a short-circuit fault  

Microsoft Academic Search

The fast development of wind power generation brings new requirements for wind turbine integration to the network. After the clearance of an external short-circuit fault, the voltage at the wind turbine terminal should be reestablished with minimized power losses. This paper concentrates on voltage recovery of variable speed wind turbines with doubly fed induction generators (DFIG). A simulation model of

T. Sun; Z. Chen; F. Blaabjerg

2004-01-01

440

Fatigue life prediction for wind turbines: A case study on loading spectra and parameter sensitivity  

Microsoft Academic Search

Wind turbines are fatigue-critical machines used to produce electrical energy from the wind. These rotating machines are subjected to environmental loadings that are highly irregular in nature. Historical examples of fatigue problems in both research and commercial wind turbine development are presented. Some example data on wind turbine environments, loadings and material properties are also shown. Before a description of

H. J. Sutherland; P. S. Veers; T. D. Ashwill

1992-01-01

441

PERFORMANCE ENHANCEMENT OF WIND TURBINE POWER REGULATION BY SWITCHED LINEAR CONTROL  

E-print Network

PERFORMANCE ENHANCEMENT OF WIND TURBINE POWER REGULATION BY SWITCHED LINEAR CONTROL D.J.Leith W Power regulation of horizontal-axis grid-connected up-wind constant-speed pitch-regulated wind turbines, switched linear control is more suited for application to wind turbines than the nonlinear control strategy

Duffy, Ken

442

A Comparative Study of Time-Frequency Representations for Fault Detection in Wind Turbine  

E-print Network

A Comparative Study of Time-Frequency Representations for Fault Detection in Wind Turbine El of wind energy, minimization and prediction of maintenance operations in wind turbine is of key importance and the easiness of interpretation. Index Terms--Wind turbine, fault detection, broken-rotor bars, signal

Paris-Sud XI, Université de

443

Performance Testing of a Small Vertical-Axis Wind Turbine , S. Tullis2  

E-print Network

Performance Testing of a Small Vertical-Axis Wind Turbine R. Bravo1 , S. Tullis2 , S. Ziada3 of electric production [1]. Although most performance testing for small-scale wind turbines is conducted vertical-axis wind turbines (VAWT) in urban settings, full-scale wind tunnel testing of a prototype 3.5 k

Tullis, Stephen

444

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

E-print Network

1 A REAL OPTIONS OPTIMIZATION MODEL TO MEET AVAILABILITY REQUIREMENTS FOR OFFSHORE WIND TURBINES wind farm with prognostic capabilities. Alternative energy sources such as offshore wind turbines heavily on the wind resources, and the availability of the turbines. Prognostics and health management

Sandborn, Peter

445

WIND TURBINE STRUCTURAL HEALTH MONITORING: A SHORT INVESTIGATION BASED ON SCADA DATA  

E-print Network

WIND TURBINE STRUCTURAL HEALTH MONITORING: A SHORT INVESTIGATION BASED ON SCADA DATA E. Papatheou1 into the energy arena. As wind turbines have become more complex, efficient, and expensive structures, and then predict measurements of the power produced of each wind turbine from the measurements of the other wind

Boyer, Edmond

446

Wind turbine gearbox health monitoring using time-frequency features from multiple sensors  

Microsoft Academic Search

As wind energy plays an increasingly important role in the US and world electricity supply, maintenance of wind turbines emerges as a critical issue. Because of the remote nature of wind turbines, autonomous and robust health monitoring techniques are necessary. Detecting faults in complex systems such as wind turbine gearboxes remains challenging, even with the recently significant advancement of sensing

Y. Lu; J. Tang

2011-01-01

447

Performance Assessment of Micro and Small-Scale Wind Turbines in Urban Areas  

Microsoft Academic Search

This paper addresses some general issues related to the difficulties and uncertainties during the assessment and characterization of micro and small-scale wind-based generation in urban areas. This paper proposes four generic wind turbine models, which could be used for the analysis and selection of optimal wind turbines in target applications, as they accurately represent the range of wind turbines currently

Jorge L. Acosta; Kevin Combe; Saša Ž Djokic; Ignacio Hernando-Gil

2012-01-01

448

Development of Trouble Diagnosis Technology of 50W Grade Small Wind Turbine Generator  

Microsoft Academic Search

Establishment of an early trouble diagnosis system is demanded to prevent damage of wind turbine generator. Therefore, AE signal occurring by the damage of a wind blade was detected with the AE sensor which installed to the body of wind turbine generator and a pole. In this study, length of a blade of a small wind turbine generator was changed

Masashige Takaoka; Kazuki Inohata; Takuma Miyake; Daisuke Tashima; Masahisa Otsubo; Toshio Bouno

2008-01-01

449

7,511,624 Wind Energy Overview: Device for monitoring the balance and integrity of wind turbine blades either in  

E-print Network

oscillations (including imbalances and tracking variations) in wind turbine blades. This technology was tested covering the RPM rate of any wind turbine blade. This invention directly targets the operational monitoring://tto.montana.edu/technologies Technology Available for License In-Field LIDAR Monitoring and Manufacturing Control of Wind Turbine Montana

Maxwell, Bruce D.

450

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

Federal Register 2010, 2011, 2012, 2013

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

2011-02-24

451

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

SciTech Connect

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

Lantz, E.; Hand, M.

2011-03-01

452

WIND TURBINE SITING IN AN URBAN ENVIRONMENT: THE HULL, MA 660 KW TURBINE  

Microsoft Academic Search

The installation in 2001 of a Vestas 660 kW wind turbine at Windmill Point in Hull, Massachusetts represents a high point in the long history of wind energy activity at this location. The site is in a highly populated coastal area, within 8 miles of Boston (city hall) and within 5 miles of Logan Airport. Its location makes this project

J. F. Manwell; J. G. McGowan; A. Rogers; A. Ellis; S. Wright; M. Brown; J. MacLeod

453

Development of large, horizontal-axis wind turbines  

NASA Technical Reports Server (NTRS)

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

Baldwin, D. H.; Kennard, J.

1985-01-01

454

Cascading Kalman Observers of Structural Flexible and Wind States for Wind Turbine Control  

Microsoft Academic Search

We formulate novel observers of the structural flexible states of a wind turbine, as well as of the wind incident on its rotor. Stochastic filtering processes reconstruct on-line optimal estimates of the tower and blade states, by using readings from accelerometers and strain gages placed along the structural members. From these re- constructed states, another filtering process estimates the wind

C. L. Bottasso; A. Croce

455

Automatic generation control of a wind farm with variable speed wind turbines  

Microsoft Academic Search

Wind farms are considered to be negative loads from the point of view of a utility manager. Modern variable-speed wind turbines offer the possibility for controlling active and reactive power separately. This paper presents a new integrated control system of a wind farm according to the utility manager's requirements. This control system is based on two control levels: a supervisory

José Luis Rodríguez-Amenedo; Santiago Arnalte; Juan Carlos Burgos

2002-01-01

456

Analysis of the effects of integrating wind turbines into a conventional utility: A case study  

NASA Astrophysics Data System (ADS)

Three aspects of the integration of wind turbine (WTG) into a selected utility generating system, are documented. The sensitivity of the economic impact of WTG to wind speed sampling frequency, wind turbine performance model and wind speed forecasting accuracy are examined. The initial phase of the study consisted of calculating the expected output of the MOD-2 wind turbine using various turbine performance models driven by wind data representing different sampling frequencies. The basic wind data set used consisted of instantaneous values of wind speed and direction recorded at 2 min intervals. Four different simulation methods were used with the wind data to estimate MOD-2 performance.

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

1983-03-01

457

Thermal power plant cooperation with wind turbines  

Microsoft Academic Search

The popularity of wind energy is increasing and that arises several technical problems like system stability and wind power reliability. Power companies have learned how to predict power consumption and therefore know how to plan power generation. Adding notable amount of wind power into the system requires a new approach to system stability. The idea of wind power is to

Ivo Palu; Heiki Tammoja; Rein Oidram

2008-01-01

458

The evolution of wind-turbines - An historical review  

NASA Astrophysics Data System (ADS)

The harnessing of wind power over the last 2000 years is considered with emphasis on the technical knowledge in Great Britain during the 20th century. Technically successful research projects on the use of wind energy failed to lead to commercial exploitation because throughout the post-war period, fossil fuels were relatively inexpensive and it was expected that the production of electricity by nuclear fission would also provide inexpensive electrical energy. The development and importance of horizontal-axis and vertical-axis wind-turbines has also been discussed. Because of economic and safety reasons, sharp rises of unit oil prices since 1973 and the realization that fossil fuel reserves are finite, governments have invested in research programs aimed at harnessing ambient energy. Although wind, which is a huge power resource, remains relatively neglected, a favorable market for wind turbines does exist due to the high costs of alternative power sources.

Fleming, P. D.; Probert, S. D.

459

The Wake of a Single Vertical Axis Wind Turbine  

NASA Astrophysics Data System (ADS)

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

Barsky, Danielle

460

Experiments of Wind Turbine Blades with Rocket Triggered Lightning  

NASA Astrophysics Data System (ADS)

This paper describes the results of the experiments of wind turbine blades with rocket triggered lightning. A number of wind power stations have been projected and planted. Lightning damage to wind turbines has been an increasing problem recently. So development on protection of wind power plants from lightning is necessary to be fully run for the future. In the experiments, the 1.8m long blade was struck by the lightning discharge triggered by rocket. For the blade kept dry inside, the very strong discharge of positive peak current 28kV, total charge 520 Coulombs, was triggered, but the breakdown did not occur through the blade into inside. Another blade polluted by salty wet inside was struck by the lightning discharge of negative peak current of 4kA with 0.5 Coulombs. The lightning was small, nevertheless, the blade was broken at the upper edge and the blade was disconnected by crack. For the protection of blade, the blade surface was covered with stainless steel plate. The blade itself was safe when the big positive lightning discharged, while most part of stainless steel cover was burned out. Supplement breakdown tests of wind turbine blade were carried out with lightning impulse voltage in laboratory. As a result, it became clear that the blade kept dry inside was an effective lightning protection of wind turbine blades.

Minowa, Masayuki; Sumi, Shinichi; Minami, Masayasu; Horii, Kenji

461

Thermal Performance of Wind Turbine Power System's Engine Room  

NASA Astrophysics Data System (ADS)

Greatly expanded use of wind energy has been proposed to reduce dependence on fossil and nuclear fuels for electricity generation. For wind turbine power generation, as a mature technology in the field of wind power utilization, its large-scale deployment is limited by the cooling technology. Therefore, the temperature distribution of the wind turbine power generation is a key issue for the design of the cooling system. It is because the characteristics of cooling system have a great effect on the performance of the wind turbine power generation. Based on some assumptions and simplifications, a thermal model is developed to describe the heat transfer behavior of wind turbine power system. The numerical calculation method is adopted to solve the governing equation. The heat generation and heat flux are investigated with a given operating boundary. The achieved results can be used to verify whether the cooling system meets the design requirements. Meanwhile, they also can reveal that among the influencing factors, the meteorological conditions, generated output and operation state as well seriously influence its thermal performance. Numerical calculation of the cooling system enables better understanding and results in performance improvement of the system.

Liu, Zhili; Jiang, Yanlong; Zhou, Nianyong; Shi, Hong; Kang, Na; Wang, Yu

462

Laboratory implementation of variable-speed wind turbine generation  

SciTech Connect

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

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

1996-07-01

463

Full-scale wind turbine rotor aerodynamics research  

SciTech Connect

The United States Department of Energy and the National Renewable Energy Laboratory (NREL) are conducting research to improve wind turbine technology at the NREL National Wind Technology Center (NWTC). One program, the Combined Experiment, has focused on making measurements needed to understand aerodynamic and structural responses of horizontal-axis wind turbines (HAWT). A new phase of this program, the Unsteady Aerodynamics Experiment, will focus on quantifying unsteady aerodynamic phenomena prevalent in stall-controlled HAWTs. Optimally twisted blades and innovative instrumentation and data acquisition systems will be used in these tests. Data can now be acquired and viewed interactively during turbine operations. This paper describes the NREL Unsteady Aerodynamics Experiment and highlights planned future research activities.

Simms, D A; Butterfield, C P

1994-11-01

464

Fatigue Failure Analysis of Small Wooden Wind Turbine Blade  

E-print Network

Advances in engineering technology in recent years have brought demands for reliable wind turbine blade which can operate at different climatic condition and speeds. When failures occur they are expensive, not only in terms of the cost of replacement or repair, but also the costs associated with the down-time of the system of which they are part. Reliability is thus a critical economic factor and for designers to produce wind turbine blade with a high reliability they need to be able to accurately predict the stresses experienced by the different load condition. A wooden 1.5m wind turbine blade was tested by means of a mechanically operated test rig for fatigue failure. The rig uses a crank eccentric mechanism by variable load for each load cycle. The stress distribution in fatigue critical areas of the blade during testing was found to be similar to the expected stress distribution under normal operational condition

Maldhure S. S; Dr. Kharde Y. R

465

Variable speed generator technology options for wind turbine generators  

NASA Astrophysics Data System (ADS)

The electrical system options for variable speed operation of a wind turbine generator were considered. Systems considered for large wind turbine generators were: (1) dc generator with line commutated inverted bridge; (2) synchronous generator with thyristor rectifier and inverter; (3) doubly fed induction generator with dc current link rectifier and inverter; (4) doubly fed induction generator with dc voltage link rectifier and inverter; and (5) doubly fed induction generator and cycloconverter. Those systems considered for smaller wind turbine generators were: (1) dc generator with copper based dc voltage link; (2) induction generator with dc voltage link; (3) induction generator with cycloconverter; (4) induction generator with high frequency link converter; and (5) permanent magnet generator configuration. The key operating characteristics of each system are discussed and the major advantages and disadvantages of each are identified.

Lipo, T. A.

1984-06-01

466

Quiet airfoils for small and large wind turbines  

DOEpatents

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

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

2012-06-12

467

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

SciTech Connect

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

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

2008-03-01

468

Methods and Apparatus for Reduction of Asymmetric Rotor Loads in Wind Turbines.  

National Technical Information Service (NTIS)

A method for reducing load and providing yaw alignment in a wind turbine includes measuring displacements or moments resulting from asymmetric loads on the wind turbine. These measured displacements or moments are used to determine a pitch for each rotor ...

E. M. Moroz, K. G. Pierce

2004-01-01

469

Airfoil family design for large offshore wind turbine blades  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

470

Wind turbine wake characterization using long-range Doppler lidar  

NASA Astrophysics Data System (ADS)

Wind turbines extract energy from the freestream flow, resulting in a waked region behind the rotor which is characterized by reduced wind speed and increased turbulence. The velocity deficit in the wake diminishes with distance, as faster-moving air outside is gradually entrained. In a concentrated group of turbines, then, downwind machines experience very different inflow conditions compared to those in the front row. As utility-scale turbines rarely exist in isolation, detailed knowledge of the mean flow and turbulence structure inside wakes is needed to correctly model both power production and turbine loading at modern wind farms. To this end, the Turbine Wake and Inflow Characterization Study (TWICS) was conducted in the spring of 2011 to determine the reduction in wind speeds downstream from a multi-MW turbine located at the National Renewable Energy Laboratory's National Wind Technology Center (NWTC) near Boulder, Colorado. Full-scale measurements of wake dynamics are hardly practical or even possible with conventional sensors, such as cup anemometers mounted on meteorological (met) masts. Accordingly, the High Resolution Doppler Lidar (HRDL) developed by the National Oceanic and Atmospheric Administration's Earth System Research Laboratory was employed to investigate the formation and propagation of wakes under varying levels of ambient wind speed, shear, atmospheric stability, and turbulence. HRDL remotely senses line-of-sight wind velocities and has been used in several previous studies of boundary layer aerodynamics. With a fully steerable beam and a maximum range up to about 5 km, depending on atmospheric conditions, HRDL performed a comprehensive survey of the wind flow in front of and behind the turbine to study the shape, meandering, and attenuation of wakes. Due in large part to limited experimental data availability, wind farm wake modeling is still subject to an unacceptable amount of uncertainty, particularly in complex terrain. Here, analytical techniques are developed to distinguish wakes from the background variability, and moreover, wakes are then classified by width, height, length, and velocity deficit based on atmospheric stability and inflow conditions. By integrating these advanced observational capabilities with innovative approaches to atmospheric modeling, this work will help to improve simulation tools used to quantify power loss and fatigue loading due to wake effects, thereby aiding the optimization of wind farm layouts.

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

2012-12-01

471

Wind Turbine Gearbox Failure Modes - A Brief (Presentation)  

SciTech Connect

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

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

2011-10-01

472

WIND TURBINE SITING IN AN URBAN ENVIRONMENT: THE HULL, MA 660 KW TURBINE  

E-print Network

The installation in 2001 of a Vestas 660 kW wind turbine at Windmill Point in Hull, Massachusetts represents a high point in the long history of wind energy activity at this location. The site is in a highly populated coastal area, within 8 miles of Boston (city hall) and within 5 miles of Logan Airport. Its location makes this project unique in the United States. This paper documents the history of this project, from its early precursors in the 1800’s, through the installation of a 40 kW Enertech machine in the 1980’s to the installation of the new turbine. The turbine is owned and operated by the Hull Municipal Light Plant (HMLP), and the project was developed by HMLP with assistance of the University of Massachusetts ’ Renewable Energy Research Laboratory and the Massachusetts Division of Energy Resources. The issues that were addressed and the factors that led to successful realization of the project are discussed here. In addition, a summary of the first year’s performance of the wind turbine is given. The paper also presents an overview of possible future wind generation projects that are under discussion in the town. These include (1) the installation of a second land-based wind turbine, (2)

J. F. Manwell; J. G. Mcgowan; A. Rogers; A. Ellis; S. Wright; M. Brown; J. Macleod

473

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

474

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

SciTech Connect

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

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

1983-03-01

475

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

SciTech Connect

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

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

1982-08-01

476

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

NASA Technical Reports Server (NTRS)

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

Loyd, B.; Harris, W. L.

1995-01-01

477

Performance and flow analysis of vortex wind power turbines  

SciTech Connect

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

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

1982-10-01

478

Modified aerospace reliability and quality assurance method for wind turbines  

NASA Technical Reports Server (NTRS)

The safety, reliability, and quality assurance (SR&QA) approach developed for the first large wind turbine generator project is described. The SR&QA approach was used to assure that the machine would not be hazardous to the public or operating personnel, would operate unattended on a utility grid, would demonstrate reliable operation and would help establish the quality assurance and maintainability requirements for future wind turbine projects. A modified failure modes and effects analysis during the design phase, minimal hardware inspections during parts fabrication, and three simple documents to control activities during machine construction and operation were presented.

Klein, W. E.

1980-01-01

479

Advanced system identification techniques for wind turbine structures  

SciTech Connect

The new approach to modal parameter identification, presented in this paper, uses an asymptotically stable observed to form a discrete state-space model for a wind turbine structure. The identification is performed using input-output time-series. A special software package developed in this research has been tested using the data generated by the ADAMS{trademark} model of the Micon 65/13 wind turbine structure. Numerical and graphical presentation of some of the results, generated by the programs developed, illustrates the range of their applicability.

Bialasiewicz, J.T.; Osgood, R.M.

1995-03-01

480

Evaluation of MOSTAS computer code for predicting dynamic loads in two bladed wind turbines  

Microsoft Academic Search

Calculated dynamic blade loads were compared with measured loads over a range of yaw stiffnesses of the DOE\\/NASA Mod-O wind turbine to evaluate the performance of two versions of the MOSTAS computer code. The first version uses a time-averaged coefficient approximation in conjunction with a multi-blade coordinate transformation for two bladed rotors to solve the equations of motion by standard

K. R. V. Kaza; D. C. Janetzke; T. L. Sullivan

1979-01-01

481

Performance of wind turbines in a turbulent atmosphere  

NASA Technical Reports Server (NTRS)

The effect of atmospheric turbulence on the power fluctuations of large wind turbines was studied. The significance of spatial non-uniformities of the wind is emphasized. The turbulent wind with correlation in time and space is simulated on the computer by Shinozukas method. The wind turbulence is modelled according to the Davenport spectrum with an exponential spatial correlation function. The rotor aerodynamics is modelled by simple blade element theory. Comparison of the spectrum of power output signal between 1-D and 3-D turbulence, shows the significant power fluctuations centered around the blade passage frequency.

Sundar, R. M.; Sullivan, J. P.

1981-01-01