WorldWideScience
 
 
1

Wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

Yeoman, J.C. Jr.

1978-12-01

2

Proposal and Development of Radial Air-gap Coreless Generator Suitable for Small Wind Turbine using in Urban Area  

Science.gov (United States)

Independent distributed generations using small wind turbines are widely spread as increasing of wind power generation. Installation of small wind turbines in densely-populated urban area is not only useful from the viewpoint of digging up wind power source in weak-wind area but also for enlightenment of renewable energy due to closing power supplies to consumptions. From the point of view, the authors proposed “urban wind power generation" using collective system with a number of small vertical wind turbines and have developed a suitable generator for low-speed vertical wind turbines such as Savonius windmill. Standardized on a coreless generator, the proposed generator is designed to let direction of magnetic fluxes radial in order to install the magnets and coils on the outer end of the generator. The change of magnet composition and flux direction gives realization of maximized speed of flux change and output voltage in the limited space. With above composition, the power of the proposed one is independent on the diameter. In this report, we describe evaluated fundamental performance of a prototype of the proposed generator. As the result of the experiments, the maximum output power of 283W was obtained. The obtained starting torque is enough small to begin to rotate at weak wind condition of no more than 1m/s. Therefore, it is clear that the proposed “radial” coreless generator is suitable for self-starting and producing high power at low speed wind.

Takahashi, Toshiyuki; Yasuda, Yoh; Ohmoto, Shingo; Hara, Takehisa

3

Turbulence and wind turbines  

International Nuclear Information System (INIS)

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

4

Type IV Wind Turbine Model  

DEFF Research Database (Denmark)

This document is created as part of the EaseWind project. The goal of this project is to develop and investigate new control features for primary response provided by wind power plants. New control features as inertial response, synchronising power and power system damping are of interest to EaseWind project to be incorporated in the wind power plant level. This document describes the Type 4 wind turbine simulation model, implemented in the EaseWind project. The implemented wind turbine model is one of the initial necessary steps toward integrating new control services in the wind power plant level. In the project, this wind turbine model will be further incorporated in a wind power plant model together with the implementation in the wind power control level of the new control functionalities (inertial response, synchronising power and power system damping). For this purpose an aggregate wind power plant (WPP) will be considered. The aggregate WPP model, which will be based on the upscaling of the individualwind turbine model on the electrical part, will make use of an equivalent wind speed. The implemented model follows the basic structure of the generic standard Type 4 wind turbine model proposed by the International Electrotechnical Commission (IEC), in the IEC61400-27-1 Committee Draft for electrical simulation models for wind power generation, which is currently under review, [1]. The Type 4 wind turbine model described in this report includes a set of adjustments of the standard Type 4 wind turbine model in order account for the dynamic features of interest to EaseWind project. The document presents a short overview of the overall structure of the wind turbine model. Descriptions of individual submodels as well as some preliminary simulation results are included to illustrate the performance of the model.

Hansen, Anca Daniela; Margaris, Ioannis D.

2014-01-01

5

Wind Turbine Blade Design  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A detailed review of the current state-of-art for wind turbine blade design is presented, including theoretical maximum efficiency, propulsion, practical efficiency, HAWT blade design, and blade loads. The review provides a complete picture of wind turbine blade design and shows the dominance of modern turbines almost exclusive use of horizontal axis rotors. The aerodynamic design principles for a modern wind turbine blade are detailed, including blade plan shape/quantity, aerofoil selection ...

Crossley, Richard J.; Schubel, Peter J.

2012-01-01

6

Parametric Study on a Horizontal Axis Wind Turbine Proposed for Water Pumping  

Directory of Open Access Journals (Sweden)

Full Text Available Water pumping is considered an economically competitive sustainable process of providing water to communities, rural areas and livestock's. A parametric analysis on HAWT is carried out to explore the influence of the performance parameters on the power generated and withdrawal quantity of water. Effect of wind speed, radius of rotor, ambient condition, well depth, and efficiencies of turbine, generator and the pump were studied and reflected in important generalized performance maps. These performance graphs are valuable in best understanding of on?design and off? design constraints of the horizontal axis wind turbine in water pumping. The blade geometry was also studied. Results showed the reasonable range of wind turbine performance and the corresponding water discharge within the abovementioned constraints. Rating and the effect of pitch angle on discharged water are also presented. Methodology necessary to achieve the abovementioned results is processed by a computer program written in Matlab

Dr. Abdullateef A. Jadallah

2014-01-01

7

Wind turbine technology  

CERN Document Server

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

Jha, A R

2010-01-01

8

Noise from wind turbines  

Energy Technology Data Exchange (ETDEWEB)

A rapid growth of installed wind power capacity is expected in the next few years. However, the siting of wind turbines on a large scale raises concerns about their environmental impact, notably with respect to noise. To this end, variable speed wind turbines offer a promising solution for applications in densely populated areas like the European countries, as this design would enable an efficient utilisation of the masking effect due to ambient noise. In rural and recreational areas where wind turbines are sited, the ambient noise originates from the action of wind on the vegetation and about the listener's ear (pseudo-noise). It shows a wind speed dependence similar to that of the noise from a variable speed wind turbine and can therefore mask the latter for a wide range of conditions. However, a problem inherent to the design of these machines is their proclivity to pure tone generation, because of the enhanced difficulty of avoiding structural resonances in the mechanical parts. Pure tones are deemed highly annoying and are severely regulated by most noise policies. In relation to this problem, the vibration transmission of structure-borne sound to the tower of the turbine is investigated, in particular when the tower is stiffened at its upper end. Furthermore, since noise annoyance due to wind turbine is mostly a masking issue, the wind-related sources of ambient noise are studied and their masking potentials assessed. With this aim, prediction models for wind-induced vegetation noise and pseudo-noise have been developed. Finally, closely related to the effect of masking, is the difficulty, regularly encountered by local authorities and wind farm developers, to measure noise immission from wind turbines. A new measurement technique has thus been developed in the course of this work. Through improving the signal-to-noise ratio between wind turbine noise and ambient noise, the new technique yields more accurate measurement results.

Fegeant, Olivier [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Building Sciences

2002-02-01

9

Wind turbine wake meandering  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Lynum, Susanne

2013-01-01

10

Wind turbine pitch optimization  

DEFF Research Database (Denmark)

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

Biegel, Benjamin; Juelsgaard, Morten

2011-01-01

11

Wind turbines. Fiction and facts  

International Nuclear Information System (INIS)

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

12

An integrated modeling method for wind turbines  

Science.gov (United States)

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

Fadaeinedjad, Roohollah

13

Vertical axis wind turbine  

International Nuclear Information System (INIS)

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

14

Wind Turbine Blade Design  

Science.gov (United States)

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

Project, Kidwind

2006-01-01

15

Aeroservoelasticity of Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis deals with the fundamental aeroelastic interaction between structural motion, Pitch action and control for a wind turbine blade. As wind turbines become larger, the interaction between pitch action, blade motion, aerodynamic forces, and control become even more important to understand and address. The main contribution of this thesis is the development of an aeroelastic blade model which on the one hand includes the important effects of steady state blade deformation, gravit...

Kallesøe, Bjarne Skovmose; Thomsen, Jon Juel; Hansen, Morten Hartvig

2007-01-01

16

The Dutch wind turbine industry  

International Nuclear Information System (INIS)

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

17

European wind turbine catalogue  

International Nuclear Information System (INIS)

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

18

Wind turbines and health  

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-01-15

19

Alcoa wind turbines  

Science.gov (United States)

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

Ai, D. K.

1979-01-01

20

Wind turbine state estimation  

DEFF Research Database (Denmark)

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

Knudsen, Torben

2014-01-01

 
 
 
 
21

Wind turbine productivity considering electrical subassembly reliability.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes a reliability model for the electrical subassemblies of geared wind turbine systems with induction generators. The model is derived considering the failure of main subassemblies and their parameters are calculated. A productivity comparison is performed between the selected wind turbine systems including reliability issues. Two methods of modification for variable-speed wind turbines with Doubly Fed Induction Generators (DFIG) to improve their availability are finally ...

Arabian-hoseynabadi, H.; Oraee, H.; Tavner, P. J.

2010-01-01

22

Wind turbine optimal control during storms  

Science.gov (United States)

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

23

Wind turbines, is it just wind?  

International Nuclear Information System (INIS)

The author first outlines that wind energy is not only random, but almost absent in extreme situations when it would be needed (for example and notably, very cold weather without wind). He suggests the association of a gas turbine to each wind turbine, so that the gas turbine will replace non operating wind turbines. He notices that wind turbines are not proximity energy as they were said to be, and that profitability in fact requires tens of grouped giant wind turbines. He also outlines the high cost of construction of grids for the connection of these wind turbines. Thus, he states that wind energy is far from being profitable in the present conditions of electricity tariffs in France

24

Superconducting Wind Turbine Generators  

DEFF Research Database (Denmark)

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

Mijatovic, Nenad

2012-01-01

25

Lightning Risk on Wind Turbine Generator Systems  

Science.gov (United States)

Recently, the number of outages of wind turbine generator systems has been increasing. For rational lightning protection design, the concept of lightning risk management has been proposed. In this paper, lightning risk assessment of the wind turbine generator systems is carried out and it is compared with field experiences. Furthermore, lightning risk management scheme is discussed.

Shindo, Takatoshi; Suda, Tomotaka

26

Predicting Noise From Wind Turbines  

Science.gov (United States)

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

Grosveld, Ferdinand W.

1990-01-01

27

Wind conditions for wind turbine design  

Energy Technology Data Exchange (ETDEWEB)

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

Maribo Pedersen, B.

1999-04-01

28

Operation Design of Wind Turbines in Strong Wind Conditions  

DEFF Research Database (Denmark)

In order to reduce the impact on the electrical grid from the shutdown of MW wind turbines at wind speeds higher than the cut-out wind speed of 25 m/s, we propose in this paper to run the turbines at high wind speeds up to 40 m/s. Two different operation designs are made for both constant speed and variable speed pitch regulated wind turbines. The variable speed design is more suitable for wind turbines to run at very high wind speeds which can help the turbine braking system to stop the turbine at the new "cut-out" wind speed. Reference power, rotational speed and pitch angle have been designed optimally. In order to reduce the possible increased loading, fatigue due to the wind gusts, control strategies have been considered for both constant sped and variable speed pitch regulated wind turbines. The control study shows that the designed controllers can reduce the standard deviations efficiently for wind turbines at some selected wind high speeds.

Shen, Wen Zhong; Poulsen, Niels KjØlstad

2012-01-01

29

Noise from wind turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Fe?geant, Olivier

2001-01-01

30

Tornado type wind turbines  

Science.gov (United States)

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

Hsu, Cheng-Ting (Ames, IA)

1984-01-01

31

Wind turbine spoiler  

Science.gov (United States)

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

Sullivan, William N. (Albuquerque, NM)

1985-01-01

32

Reliability analysis for wind turbines.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Modern wind turbines are complex aerodynamic, mechanical and electrical machines incorporating sophisticated control systems. Wind turbines have been erected in increasing numbers in Europe, the USA and elsewhere. In Europe, Germany and Denmark have played a particularly prominent part in developing the technology, and both countries have installed large numbers of turbines. This article is concerned with understanding the historic reliability of modern wind turbines. The prime objective of t...

Tavner, P. J.; Xiang, J.; Spinato, F.

2006-01-01

33

High-efficiency wind turbine  

Science.gov (United States)

Vertical axis wind turbine incorporates several unique features to extract more energy from wind increasing efficiency 20% over conventional propeller driven units. System also features devices that utilize solar energy or chimney effluents during periods of no wind.

Hein, L. A.; Myers, W. N.

1980-01-01

34

Wind turbine aerodynamics  

Energy Technology Data Exchange (ETDEWEB)

The need for clean, renewable electricity in remote communities of Canada and the world was discussed in this presentation. The University of Waterloo Wind Energy Laboratory (WEL) performs research in a large scale indoor environment on wind turbines, blade aerodynamics, and aeroacoustics. A key area of research involves developing turbines for remote off-grid communities where climatic conditions are challenging. This presentation outlined research that is underway on wind energy and off-grid renewable energy systems. Many communities in Canada and remote communities in the rest of the world are not connected to the grid and are dependent on other means to supply electrical energy to their community. Remote communities in northern Canada have no road access and diesel is the dominant source of electrical energy for these communities. All of the community supply of diesel comes from brief winter road access or by air. The presentation discussed existing diesel systems and the solution of developing local renewable energy sources such as wind, hydro, biomass, geothermal, and solar power. Research goals, wind energy activities, experimental equipment, and the results were also presented. Research projects have been developed in wind energy; hydrogen generation/storage/utilization; power electronics/microgrid; and community engagement. figs.

Johnson, D.A. [Waterloo Univ., ON (Canada). Dept. of Mechanical Engineering, Wind Energy Group

2010-07-01

35

Rotating transformers in wind turbine applications  

Energy Technology Data Exchange (ETDEWEB)

The power consumption of rotating electrical components is often supplied via slip-rings in wind turbines. Slip-ring equipment is expensive and need maintenance and are prone to malfunction. If the slip-rings could be replaced with contact-less equipment better turbines could be designed. This paper presents the design, some FE calculations and some measurements on a prototype rotating transformer. The proposed transformer consists of a secondary rotating winding and a stationary exciting primary winding. The results indicate that this transformer could be used to replace slip-rings in wind turbines. 4 refs, 3 figs

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

1996-12-01

36

Great expectations: large wind turbines  

International Nuclear Information System (INIS)

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

37

Aeroservoelasticity of Wind Turbines  

DEFF Research Database (Denmark)

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

KallesØe, Bjarne Skovmose

2007-01-01

38

Aeroservoelasticity of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

Skovmose Kallesoee, B.

2007-12-14

39

Small Wind Turbine Technology Assessment  

International Nuclear Information System (INIS)

The result of the study carried out under the scope of the ATYCA project Test Plant of Wind Systems for Isolated Applications, about the state of art of the small wind turbine technology (wind turbines with swept area smaller than 40 m2) is presented. The study analyzes the collected information on 60 models of wind turbines from 23 manufacturers in the worldwide market. Data from Chinese manufacturers, that have a large participation in the total number of small wind turbines in operation, are not included, due to the unavailability of the technical information. (Author) 15 refs

40

Ultimate loading of wind turbines  

DEFF Research Database (Denmark)

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

Larsen, Gunner Chr.; Ejsing JØrgensen, Hans

1999-01-01

 
 
 
 
41

Harmonic Current Predictors for Wind Turbines  

Directory of Open Access Journals (Sweden)

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

Shun-Yu Chan

2013-03-01

42

Composite wind turbine towers  

Energy Technology Data Exchange (ETDEWEB)

This paper discussed experiments conducted to optimized the advanced composite materials such as fiberglass reinforced plastics (FRP) used to fabricate wind turbine towers. FRP materials are used in tubular steel, lattice, guyed, and reinforced concrete towers. The towers and turbine blades are transported in segments and assembled on-site, sometimes in offshore or remote locations.The FRP composites are used to build towers with a high strength-to-weight ratio as well as to provide resistance to chemical attacks and corrosion. Use of the materials has resulted in towers that do not require heavy installation equipment. Experimental programs were conducted to verify the structural behaviour of the tower structure's individual-scaled cells as well as to evaluate the performance of multi-cell assemblies. Joint assembly designs were optimized, and a filament winding machine was used to conduct the experimental study and to test individual cells. Failure mode analyses were conducted to determine local buckling and shear rupture. Tension, compression, and shear properties of the FRP materials were tested experimentally, and data from the test were then used to develop finite element models of the composite towers as well as to obtain load deflection curves and tip oscillation data. A case study of a 750 kW wind turbine in Churchill, Manitoba was used to test the design. tabs., figs.

Polyzois, D. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Civil Engineering

2008-07-01

43

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

DEFF Research Database (Denmark)

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

Zhang, Yunqian; Chen, Zhe

2011-01-01

44

Wind Turbine Providing Grid Support  

DEFF Research Database (Denmark)

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

Tarnowski, Germán Claudio Technical University of Denmark,

45

Introduction to wind turbine aerodynamics  

CERN Document Server

Wind-Turbine Aerodynamics is a self-contained textbook which shows how to come from the basics of fluid mechanics to modern wind turbine blade design. It presents a fundamentals of fluid dynamics and inflow conditions, and gives a extensive introduction into theories describing the aerodynamics of wind turbines. After introducing experiments the book applies the knowledge to explore the impact on blade design.The book is an introduction for professionals and students of very varying levels.

Schaffarczyk, Alois Peter

2014-01-01

46

Online wind turbine measurement laboratory  

Digital Repository Infrastructure Vision for European Research (DRIVER)

As part of the International Master of Science Program in Wind Energy at DTU, a complete interactive wind turbine measurement laboratory has been developed. A 500 kW stall regulated wind turbine has been instrumented with sensors for recording 1) turbine operational parameters, 2) meteorological conditions, 3) electrical quantities and 4) mechanical loads in terms of strain gauge signals. The data acquisition system has been designed and implemented by Risø together with students and teacher...

Hansen, K. S.; Helgesen Pedersen, K. O.; Schmidt Paulsen, U.

2012-01-01

47

Reliability Analysis of Wind Turbines  

DEFF Research Database (Denmark)

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

Toft, Henrik Stensgaard; SØrensen, John Dalsgaard

2008-01-01

48

Numerical investigation of wind turbine and wind farm aerodynamics  

Science.gov (United States)

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

49

Superconducting wind turbine generators  

Science.gov (United States)

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

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

2010-03-01

50

Superconducting wind turbine generators  

International Nuclear Information System (INIS)

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

51

Wind tunnel investigation on wind turbine wakes and wind farms  

Science.gov (United States)

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

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

2012-04-01

52

Effects of Icing on Wind Turbine Fatigue Loads  

Science.gov (United States)

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

Frohboese, Peter; Anders, Andreas

2007-07-01

53

Operational monitoring of horizontal axis wind turbines with inertial measurements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Operational monitoring of wind turbine rotor blades was proposed in this research as an enabling technology for structural load and damage identification, improved turbine control, and future smart adaptive enhancements of wind turbines. The objective of operational monitoring was to estimate the quasi-static and dynamic loading and deflection of an operating wind turbine rotor. To enable operational monitoring, methods for sensor selection, placement, and fabrication and algorithms for estim...

White, Jonathan Raymond

2010-01-01

54

Online wind turbine measurement laboratory  

DEFF Research Database (Denmark)

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

Schmidt Paulsen, U.

2006-01-01

55

Extreme Response for Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

2009-01-01

56

Wind Turbines Adaptation to the Variability of the Wind Field  

Science.gov (United States)

WIND TURBINES ADAPTATION TO THE VARIABILITY OF THE WIND FIELD The subject of our scientific research is wind power turbines (WPT) with the horizontal axis which were now common in the world. Efficient wind turbines work is largely determined by non-stationarity of the wind field, expressed in its gustiness, the presence of vertical and horizontal shifts of wind speed and direction. At critical values of the wind parameters WPT has aerodynamic and mechanical overload, leading to breakdowns, premature wear and reduce the life of the wind turbine. To prevent accidents at the peak values of wind speed it is used the regulatory system of windwheels. WPT control systems provide a process orientation of the wind turbine rotor axis in the line of the mean wind. Wind turbines are also equipped with braking device used to protect against breakdowns when a significant increase in the wind. In general, all these methods of regulation are not always effective. Thus, in practice there may be situations when the wind speed is many times greater than the stated limit. For example, if there are microbursts in the atmospheric boundary layer, low-level wind shears caused by its gust front, storms, etc. It is required for a wind power turbine adaptation to intensive short-term wind impulses and considerable vertical wind shifts that the data about them shall be obtained ahead of time. To do this it is necessary to have the information on the real structure of the wind field in the area of the blade sweep for the minimum range against the wind that is determined by the mean speed and the system action time. The implementation of acoustic and laser traditional wind sounding systems is limited by ambient acoustic noise, by heavy rain, snowfall and by fog. There are free of these disadvantages the inclined radioacoustic sounding (IRASS) technique which works for a system of remote detection and control of wind gusts. IRASS technique is realized as low-potential Doppler pulse radar including combined RF-acoustic antenna installed coaxially with the gondola of the wind power turbine. The work of the technique is synchronized with rotation of blades to eliminate their shielding action. Dangerous in terms of dynamic strength is the wind load pulse, the rise time which is comparable with the period of the natural frequency of the wind turbine elements (blade, tower, rotor, etc.). The amplitude decay of resonant vibrations at critical values of the speed of rotation can be realized through the use of mechanical elastic supports with nonlinear artificial dampers. They have a high coefficient of resistance, but may cause self-excited oscillations. We propose the way to deal with raised vibration of wind turbine elements at the expense of short-term increase of damping in the range of critical rotary axis speeds or during impulsive effects of wind loadings (wind gusts). This is possible through the use of non-linear electromagnetic dampers or active magnetic bearings. Their feature is the possibility of varying the mechanical stiffness and damping properties by changing the electrical parameters of electromagnets. The controlling of these parameters is carried out by the control system (CS) with the information feedback on the spatial-temporal structure of the wind field obtained from IRASS. In the composition of the CS can also be included the rotational speed sensor of the WPT rotor. This approach to the adaptation of wind turbines will allow to reduce vibration and to perform early compensation of the load on their components, which arise under the wind gusts. In addition, corrections about the wind field obtained with IRASS, would increase the mean power of WPT.

Ulianov, Yuriy; Martynenko, Gennadii; Misaylov, Vitaliy; Soliannikova, Iuliia

2010-05-01

57

Design of 50 kilowatt wind turbine blade  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The diploma thesis presents the development of wind turbine blade. The wind turbine blade is a part of the rotor for wind turbine which exploits the wind energy due to its design that is later generated into the electricity. The wind turbine blade, having a better efficiency, namely one that will produce more power than its predecessor, needs to be developed. The main characteristics, methods and instructions how to develop an efficient wind turbine blade are described in the first part of th...

Podgrajs?ek, Simon

2013-01-01

58

Potential health impact of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

NONE

2010-05-15

59

Wind turbine rotor aileron  

Science.gov (United States)

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

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

1994-06-14

60

Airship-floated wind turbine  

Energy Technology Data Exchange (ETDEWEB)

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

Watson, W. K.

1985-01-01

 
 
 
 
61

Design Tool for Direct Drive Wind Turbine Generators : Proposed solutions for direct drive Darrieus generators 20MW  

DEFF Research Database (Denmark)

The current work offers a comparison of the proposed machine geometries for 6 [MW] direct drive wind generator candidates with the prospective of up scaling to 20MW. The suggestions are based on a design tool especially built for this investigation. The in-built flexibility of the design tool gives the possibility of calculating a large variation of geometries using existing modules. The main goal is to be able to quickly and transparently asses the feasibility of a proposed machine for a set of requirements. As a first step, a set of suitable machine types for the 6 [MW] design were investigated. A comparison of the selected machine types in view of up-scaling to 20 [MW] was performed. As an example fitness criterion, the use of active materials for the generators was considered. Based on this, suggestions for 20 [MW] generators were made. The results are discussed and future work, directions and suggestions for potential improvement were listed. The design is obtained analytically at first; then visualised in 3D CAD (Computer Assisted Design) and evaluated in FEM. An analytical optimisation (Particle Swarm –PSO and Genetic Algorithms -GA) patch is available for improving the design. The tool is destined for engineers that are involved in the design of wind turbine systems. The visualisation of the design in work is important for the overall assessment of the machine concept. The tool provides facilities for reporting on a shaped design: list of geometrical and electromagnetic quantities, pictures of the machine itself (3D particular drawing); FEM (Finite Element Model) electromagnetic profile, dynamic simulation model results and characteristic curves. The structure of the design tool is modular and independent so that new machine types and geometries can be designed by reusing recombining and altering the different calculation modules. The design algorithm is transparent as logging of location and comments is used throughout the program. The purpose of this is to enable further development of the design tool by several contributors. The tool was validated by both software and laboratory tests on a prototype and by comparing results with literature reporting of similar machines.

Leban, Krisztina Monika

2014-01-01

62

SERI advanced wind turbine blades  

Science.gov (United States)

The primary goal of the Solar Energy Research Institute's (SERI) advanced wind turbine blades is to convert the kinetic energy in the wind into mechanical energy in an inexpensive and efficient manner. To accomplish this goal, advanced wind turbine blades have been developed by SERI that utilize unique airfoil technology. Performance characteristics of the advanced blades were verified through atmospheric testing on fixed-pitch, stall-regulated horizontal-axis wind turbines (HAWTs). Of the various wind turbine configurations, the stall-regulated HAWT dominates the market because of its simplicity and low cost. Results of the atmospheric tests show that the SERI advanced blades produce 10 percent to 30 percent more energy than conventional blades.

Tangler, J.; Smith, B.; Jager, D.

1992-02-01

63

Wind turbines and environment management  

Science.gov (United States)

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

Vaneck, P.; Koekebakker, P.

1983-05-01

64

Innovation in wind turbine design  

CERN Document Server

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

Jamieson, Peter

2011-01-01

65

Wind turbines for pumping oil  

Energy Technology Data Exchange (ETDEWEB)

The object of this project was to assess the technical and economic feasibility of utilizing wind turbine generators to produce electrical power for operating oil well pumpjack motors. Three Saskoil leases had wind monitoring equipment installed, which collected atmospheric data over a one year period. A review of commercially available wind turbine generators was conducted and using the atmospheric data, two different systems were designed, costed, and analyzed for techno-economic feasibility. System I uses a wind turbine generator to supply power in an attempt to reduce utility costs at a lease presently serviced by a utility network. System II uses a wind turbine generator to supply all the electrical power required to continuously operate a remote location lease which does not have utility power available. The wind system is compared to a remote lease which uses propane to power the pumpjack. The conclusions were as follows: the application of wind turbine generating systems to oil well pumping operations is not economically feasible at present; both wind power systems evaluated were technically feasible to construct and operate by using existing commercial equipment; the widespread use of wind power systems in the oilfield is unlikely due to factors such as unknown reliability in oil wellpumping situations, operational problems, and high operating costs. 10 figs, 9 tabs.

1984-01-01

66

Wind turbine storage systems  

International Nuclear Information System (INIS)

Electric power is often produced in locations far from the point of utilization which creates a challenge in stabilizing power grids, particularly since electricity cannot be stored. The production of decentralized electricity by renewable energy sources offers a greater security of supply while protecting the environment. Wind power holds the greatest promise in terms of environmental protection, competitiveness and possible applications. It is known that wind energy production is not always in phase with power needs because of the uncertainty of wind. For that reason, energy storage is the key for the widespread integration of wind energy into the power grids. This paper proposed various energy storage methods that can be used in combination with decentralized wind energy production where an imbalance exists between electricity production and consumption. Energy storage can play an essential role in bringing value to wind energy, particularly if electricity is to be delivered during peak hours. Various types of energy storage are already in use or are being developed. This paper identified the main characteristics of various electricity storage techniques and their applications. They include stationary or embarked storage for long or short term applications. A comparison of characteristics made it possible to determine which types of electricity storage are best suited for wind energy. These include gravity energy; thermal energy; compressed air energy; coupled stornergy; compressed air energy; coupled storage with natural gas; coupled storage with liquefied gas; hydrogen storage for fuel cells; chemical energy storage; storage in REDOX batteries; storage by superconductive inductance; storage in supercondensers; and, storage as kinetic energy. 21 refs., 21 figs

67

Noise immission from wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

NONE

1999-07-01

68

Noise immission from wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

NONE

1999-10-01

69

Reliability Assessment Of Wind Turbines  

DEFF Research Database (Denmark)

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

SØrensen, John Dalsgaard

2014-01-01

70

Probabilistic Design of Wind Turbines  

Directory of Open Access Journals (Sweden)

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

Henrik S. Toft

2010-02-01

71

Control of an offshore wind turbine modeled as discrete system  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Guimara?es, Pedro; A?vila, Suzana

2013-01-01

72

The aerodynamics of wind turbines  

DEFF Research Database (Denmark)

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

SØrensen, Jens NØrkær; Mikkelsen, Robert Flemming

2013-01-01

73

Lightning protection of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-03-01

74

Footprinting wind turbine fatigue loads  

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-09-01

75

Active robust control of wind turbines  

Science.gov (United States)

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

Rezaei, Vahid

76

Wind turbine wakes for wind energy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

During recent years, wind energy has moved from an emerging technology to a nearly competitive technology. This fact, coupled with an increasing global focus on environmental concern and a political desire of a certain level of diversification in the energy supply, ensures wind energy an important role in the future electricity market. For this challenge to be met in a cost-efficient way, a substantial part of new wind turbine installations is foreseen to be erected in big onshore or offshore...

Larsen, Gunner C.; Crespo Marti?nez, Antonio

2011-01-01

77

Generalized gain scheduling for deloaded wind turbine operation  

DEFF Research Database (Denmark)

The ability to produce less power than what is available from a wind source, a condition known as deloaded operation, is needed for a wind turbine to reproduce synchronous machine behavior in terms of inertial response and frequency droop regulation. Deloaded operation requires the ability to regulate both power production and rotor speed under any wind speed conditions. In this paper, a novel controller for deloaded wind turbine operation is presented. This controller is made possible by a Cp table inversion procedure allowing generalized gain scheduling for linearization of the pitch response. After introducing the wind turbine models, a review of classical turbine control principles and the proposed deloaded wind turbine control architecture is presented. A discussion of wind turbine non linearity and linearization principles follows. Simulation results are shown for stability, immunity to icing and performance. The advantages of generalized gain scheduling over classical gain scheduling are demonstrated by simulation results.

Venne, Philippe; Guillaud, X.

2010-01-01

78

Asynchronous Generators for use in Gearless Wind Turbines  

DEFF Research Database (Denmark)

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

Jensen, Bogi Bech Technical University of Denmark,

2011-01-01

79

Foundations for offshore wind turbines.  

Science.gov (United States)

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

Byrne, B W; Houlsby, G T

2003-12-15

80

Noise from offshore wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

Soendergaard, B.; Plovsing, B.

2005-07-01

 
 
 
 
81

Control system on a wind turbine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Varpe, Steffen Andreas

2008-01-01

82

Nonlinear Dynamics of Wind Turbine Wings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Wind turbines with a nominal effect of 5MW with a rotor diameter of up to 126m are produced today. With the increasing size wind turbines also become more and more optimized with respect to structural dimensions and material usage, without increasing the stiffness proportionally. Consequently, large wind turbines become increasingly flexible and dynamically sensitive. This project focuses on the structural analysis of highly flexible wind turbine wings, and the aerodynamic loading of wind tur...

Larsen, Jesper Winther

2006-01-01

83

Load Extrapolation During Operation for Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the recent years load extrapolation for wind turbines has been widely considered in the wind turbine industry. Loads on wind turbines during operations are normally dependent on the mean wind speed, the turbulence intensity and the type and settings of the control system. All these parameters must be taken into account when characteristic load effects during operation are determined. In the wind turbine standard IEC 61400-1 a method for load extrapolation using the peak over threshold meth...

Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

2008-01-01

84

Results of a wind turbine FDI competition  

DEFF Research Database (Denmark)

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

Odgaard, Peter Fogh; Stoustrup, Jakob

2012-01-01

85

Active control: Wind turbine model  

DEFF Research Database (Denmark)

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

Bindner, H.

1999-01-01

86

Active control: Wind turbine model  

Energy Technology Data Exchange (ETDEWEB)

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

Bindner, Henrik

1999-07-01

87

Wind Turbines and Human Health  

Science.gov (United States)

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

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

2014-01-01

88

Wind energy. From small wind turbines to offshore wind farms  

International Nuclear Information System (INIS)

This bibliographical sheet presents a book in which the authors present and discuss the present and future developments, challenges and problematic of wind energy. They notably focus on offshore wind farms, their technical solutions and current French projects, with their potentials, economic, administrative and environmental aspects, their sizing issue, and so on. They also explain in detail the potential of wind energy and its conversion, present the different subsystems of a wind turbine and their operation, and describe how to build up a wind farm project. They also address the issues related to small wind turbines

89

Extended Kalman Filter based State Estimation of Wind Turbine  

Directory of Open Access Journals (Sweden)

Full Text Available State estimation provides the best possible approximation for the state of the system by processing the available information. In the proposed work, the state estimation technique is used for the state estimation of wind turbine. Modern wind turbines operate in a wide range of wind speeds. To enable wind turbine operation in such a variety of operating conditions, sophisticated control and estimationalgorithms are needed. The theoretical basis of Extended Kalman Filter algorithm is explained in detail and performance is tested with the simulation. A nonlinear state estimator named ExtendedKalman Filter can be used for estimating the states of wind turbine. The Extended Kalman Filter is a recursive estimator that can be decomposed into two phases such as prediction and correction performed at every time instant. The states estimated by usingExtended Kalman Filter for wind turbine application includes rotor speed of turbine, tower top displacement and its velocity.

Kavitha N

2013-11-01

90

Diffuser augmented wind turbine analysis code  

Science.gov (United States)

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, it is necessary to develop innovative wind capturing devices that can produce energy in the locations where large conventional horizontal axis wind turbines (HAWTs) are too impractical to install and operate. A diffuser augmented wind turbine (DAWT) is one such innovation. DAWTs increase the power output of the rotor by increasing the wind speed into the rotor using a duct. Currently, developing these turbines is an involved process using time consuming Computational Fluid Dynamics codes. A simple and quick design tool is necessary for designers to develop efficient energy capturing devices. This work lays out the theory for a quick analysis tool for DAWTs using an axisymmetric surface vorticity method. This method allows for quick analysis of duct, hubs and rotors giving designers a general idea of the power output of the proposed hub, blade and duct geometry. The method would be similar to the way blade element momentum theory is used to design conventional HAWTs. It is determined that the presented method is viable for preliminary design of DAWTs.

Carroll, Jonathan

91

Fault tolerant control of wind turbines using unknown input observers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Odgaard, Peter Fogh; Stoustrup, Jakob

2013-01-01

92

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-03-01

93

Vertical axis wind turbine airfoil  

Science.gov (United States)

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

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

2012-12-18

94

Wind Turbine Control: Robust Model Based Approach  

DEFF Research Database (Denmark)

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

Mirzaei, Mahmood

2012-01-01

95

Bayesian network for wind turbine fault diagnosis.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Wind turbine reliability studies have become more important because good wind turbine reliability with predictable turbine maintenance schedule will reduce the cost of energy and determine the success of a wind farm project. Previous research on wind turbine SCADA system has made progress in this respect. However, SCADA data volume is usually too huge and alarm information is too unclear to indicate failure root causes. In addition, SCADA signals and alarms are not currently interpreted as a ...

Chen, Bindi; Tavner, P. J.; Feng, Y.; Song, W. W.; Qiu, Y. N.

2012-01-01

96

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

Science.gov (United States)

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

97

Predicting Faults in Wind Turbines Using SCADA Data  

DEFF Research Database (Denmark)

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

Borchersen, Anders Bech; Larsen, Jesper Abildgaard

2013-01-01

98

Hywind floating wind turbine project  

Energy Technology Data Exchange (ETDEWEB)

The Hywind floating wind turbine concept was developed by StatoilHydro. Technip was awarded the contract for engineering, fabrication and installation of a demonstration unit in May 2008 and the completed wind turbine was installed mid June 2009 at the west coast of Norway on 220 m water depth. The demonstration unit will generate 2,3 MW and is equipped with instrumentation for monitoring mooring forces, strains and motions. The fabrication of the SPAR type steel substructure was performed at Technip Offshore Finland facilities in Pori and was towed horizontally from Finland to Norway, where it was upended to a vertical position by water filling. The completed floating wind turbine was towed vertically to the final location west of Karmoey and connected to the pre-installed three legged anchor system using an Anchor Handling Tug type vessel. The wind turbine test period is scheduled to start in September 2009. Statoil will monitor the performance of the system for two years before decision will be taken for further development. The paper will present the main challenges and lessons learned through design, fabrication and installation of this first of its kind structure. Main emphasis will be on the special challenges experienced for this floating, catenary moored, slender unit which is highly exposed for wind induced forces in addition to current and waves in hostile North Sea environments. (Author)

Crome, Tim

2010-07-01

99

A novel floating offshore wind turbine concept  

DEFF Research Database (Denmark)

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

Vita, Luca; Schmidt Paulsen, Uwe

2009-01-01

100

The noise generated by wind turbines  

International Nuclear Information System (INIS)

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

 
 
 
 
101

Economics of Small Wind Turbines  

Science.gov (United States)

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

2012-10-02

102

Wind turbine noise. Primary noise sources  

Energy Technology Data Exchange (ETDEWEB)

Wind is a clean, cheap, and inexhaustible source of energy. However, the noise from wind turbines constitutes an important hindrance for the widespread application of wind energy. As a result, there is considerable interest in wind turbine noise, from a number of angles. As public clamour grows from those living near turbines, and misinformation and disinformation begin to take root, there is a clear need for a scientifically accurate book to give an account of the noise generated, its effects on people, and possible remedies either through technology or legislation or both. The different potential source mechanisms are described and the theoretical characteristics of flowinduced sound from wind turbine blades are explained. The noise sources on wind turbines are characterized experimentally by means of wind tunnel and field experiments. Methods to predict and reduce wind turbine noise are discussed. The dominant noise source for typical modern large wind turbines is broadband trailing edge noise from the outer part of the blades. The swishing character of the sound can be explained by trailing edge noise directivity and convective amplification. A semi-analytical, semi-empirical prediction method can accurately predict the characteristics of wind turbine noise. Wind turbine noise can be halved by means of serrations, without adverse effects on the aerodynamic performance. The book is aimed at people with a personal or professional involvement in wind turbine noise, such as environmental health or public health practitioners, wind farm developers or informed wind farm supporters and objectors.

Oerlemans, S.

2011-04-15

103

New guidelines for wind turbine gearboxes  

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-12-31

104

Dynamic modeling and simulation of wind turbines  

International Nuclear Information System (INIS)

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

105

Integrated installation for offshore wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

Way, J.; Bowerman, H.

2003-07-01

106

Transportation Excellence for Wind Turbine Nacelle  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Babu Thennarasu, Ganesh; Kumar Annamalai Muralidharan, Hemanth

2012-01-01

107

Probabilistic Design of Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Probabilistic design of wind turbines requires definition of the structural elements to be included in the probabilistic basis: e.g., blades, tower, foundation; identification of important failure modes; careful stochastic modeling of the uncertain parameters; recommendations for target reliability levels and recommendation for consideration of system aspects. The uncertainties are characterized as aleatoric (physical uncertainty) or epistemic (statistical, measurement and model uncertainties...

Toft, Henrik S.; Sørensen, John D.

2010-01-01

108

Small-Scale Vertical Axis Wind Turbine Design  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Castillo Tudela, Javier

2011-01-01

109

Risk of collision between service vessels and offshore wind turbines  

International Nuclear Information System (INIS)

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

110

Sound wave contours around wind turbine arrays  

International Nuclear Information System (INIS)

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

111

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

Energy Technology Data Exchange (ETDEWEB)

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

2004-11-01

112

MNR proposes wind development policy  

Energy Technology Data Exchange (ETDEWEB)

A proposed 'Policy for Wind Power Development on Crown Land' has been released by the Ontario Ministry of Natural Resources. One of the proposed policy initiatives concerns a Wind Land Rental Charge, based on the nameplate capacity of each turbine and the average Power Purchase Agreement price per kWh. Remote communities and small-scale stand-alone wind energy systems of 50 kW or less, would be exempted from paying the wind land rental charge. Three methods of applying for permits to generate wind power on crown lands are proposed: (1) First Right to Explore, costing $20,000 plus $300 per grid cell; (2) Public Tender Offering, for those with limited up-front financial resources who nevertheless wish to enter into competitive bidding; and (3) Remote Community or Small-Scale System, with exclusive rights to explore, costing $1,000, plus $300 per grid cell. According to the President of the Canadian Wind Energy Association (CWEA) the proposed policy sets royalties too high: since private landowners are charging less, the government is in fact, pricing itself out of the market. In the view of the Association the government's objective should be to free up crown land and encourage the development of the green market, rather than attempt to make money off it. The President of the CWEA believes that unless the policy is changed, development is not likely to happen on crown land, so not only will the government not get the revenue, but the electricity that would be generated by wind power won't be supplied, and electricity prices will be higher.

Anon

2003-06-01

113

RBI Optimization of Offshore Wind Turbines  

DEFF Research Database (Denmark)

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

Ramírez, José G. Rangel; SØrensen, John Dalsgaard

2009-01-01

114

Large, horizontal-axis wind turbines  

Science.gov (United States)

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

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

1984-01-01

115

Dynamic Models for Wind Turbines and Wind Power Plants  

Energy Technology Data Exchange (ETDEWEB)

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

Singh, M.; Santoso, S.

2011-10-01

116

Method and apparatus for wind turbine braking  

Energy Technology Data Exchange (ETDEWEB)

A method for braking a wind turbine including at least one rotor blade coupled to a rotor. The method includes selectively controlling an angle of pitch of the at least one rotor blade with respect to a wind direction based on a design parameter of a component of the wind turbine to facilitate reducing a force induced into the wind turbine component as a result of braking.

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

2009-02-10

117

Lightning Striking Characteristics to Wind Turbine Blades  

Science.gov (United States)

Lightning striking characteristics to wind turbine blades have been investigated by the model experiments with actual turbine blades. The effects of various types of receptors, polarities of applied voltages, pollution on the blade surface have been clarified. Based on these experimental results, lightning protection design of actual wind turbine blades by receptors has been discussed.

Shindo, Takatoshi; Asakawa, Akira; Miki, Megumu

118

On the Fatigue Analysis of Wind Turbines  

Energy Technology Data Exchange (ETDEWEB)

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

Sutherland, Herbert J.

1999-06-01

119

Wind Turbine Manufacturing Process Monitoring  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-04-26

120

Cooperative investment in wind turbines  

International Nuclear Information System (INIS)

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

 
 
 
 
121

Motion of floating wind turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Linde, Børge

2010-01-01

122

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

Energy Technology Data Exchange (ETDEWEB)

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

Huskey, A.

2011-11-01

123

bats and single wind turbine notification  

Single Turbine Planning Applications and Bats We are aware that applicants and agents are experiencing difficulties when addressing NIEA Natural Heritage requirements in relation to the impacts of single wind turbine on...

124

Standards for measurements and testing of wind turbine power quality  

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-03-01

125

Wind turbine power tracking using an improved multimodel quadratic approach.  

Science.gov (United States)

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

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

2010-07-01

126

Development of Superconducting Wind Turbine Generators  

DEFF Research Database (Denmark)

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

Jensen, Bogi Bech; Mijatovic, Nenad

2012-01-01

127

Development of superconducting wind turbine generators  

DEFF Research Database (Denmark)

In this paper, the commercial activities in the field of superconducting machines, particularly superconducting wind turbine generators, are reviewed and presented. Superconducting generators have the potential to provide a compact and light weight drive train at high torques and slow rotational speeds, because high magnetic fields can be produced by coils with very little loss. Three different superconducting wind turbine generator topologies have been proposed by three different companies. One is based on low temperature superconductors; one is based on high temperature superconductors; and one is a fully superconducting generator based on MgB2. It is concluded that there is large commercial interest in superconducting machines, with an increasing patenting activity. Such generators are, however, not without their challenges. The superconductors have to be cooled down to somewhere between 4 K and 50 K, depending on what type of superconductor is employed, which poses a significant challenge both from a construction and operation point of view. The high temperature superconductors can facilitate a higher operation temperature and simplified cooling, but the current price and production volumes prohibit a large scale impact on the wind sector. The low temperature superconductors are readily available, but will need more sophisticated cooling. Eventually the Cost of Energy from superconducting wind turbines, with particular emphasis on reliability, will determine if they become feasible or not and for such investigations large-scale demonstrations will be needed. © 2013 AIP Publishing LLC.

Jensen, Bogi Bech; Mijatovic, Nenad

2013-01-01

128

Climate change drives wind turbines  

International Nuclear Information System (INIS)

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

129

Climate change drives wind turbines  

International Nuclear Information System (INIS)

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

130

Aerodynamic Electrical Energy: Wind Turbine Engineering  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Renewable resources such as wind, solar, and water, are important in energy production. This project was to design a wind turbine electricity generation system and gain an understanding of the engineering involved in producing electricity from the wind. Having observed the wind patterns on the campus of Utah State University, it was decided to obtain both a horizontal axis (HAWT) and a vertical axis wind turbine (VAWT) and mount them on the roof of the USU Dean F. Peterson, Jr. Engineering La...

Nielson, Andrew; Marchant, Scott; Baker, Doran; Engh, Michael; Kang, Alvin; Estrada, Gustavo; Graham, Brandon; Johnson, Jason; Nieveen, Jacob

2012-01-01

131

Optimal Structural Reliability of Offshore Wind Turbines  

DEFF Research Database (Denmark)

The main failure modes of modern large wind turbines are fatigue failure of wings, hub, shaft and main tower, local buckling of main tower, and failure of the foundation. This paper considers reliability-based optimal design of wind turbines. Compared to onshore wind turbines and building structures, humans spent little time in the vicinity of offshore wind turbines and the probability of human injury during storm conditions is small. Further environmental pollution will also in general be small in case of failure. One could therefore argue that the reliability level of offshore wind turbines can be lower than for onshore wind turbines and other civil engineering structures and can be assessed by reliability-based cost-optimization. Specifically this paper considers the main tower and foundation. Both fatigue and ultimate strength failure modes are included. Different formulations of the objective function are considered.

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

2005-01-01

132

Wind turbine aerodynamics research needs assessment  

Science.gov (United States)

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

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

1986-01-01

133

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

Energy Technology Data Exchange (ETDEWEB)

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

Guillet, R.; Leteurtrois, J.P.

2004-07-01

134

On System Identification of Wind Turbines  

DEFF Research Database (Denmark)

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

Kirkegaard, Poul Henning; Perisic, Nevena

135

Small Wind Research Turbine: Final Report  

Energy Technology Data Exchange (ETDEWEB)

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

Corbus, D.; Meadors, M.

2005-10-01

136

Adaptive Fuzzy Logic Control of Wind Turbine Emulator  

Directory of Open Access Journals (Sweden)

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

BOUZID Mohamed Amine

2014-03-01

137

Grid support capabilities of wind turbines  

DEFF Research Database (Denmark)

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

Hansen, Anca Daniela

2013-01-01

138

Large superconducting wind turbine generators  

DEFF Research Database (Denmark)

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

Abrahamsen, Asger Bech; Jensen, Bogi Bech

2012-01-01

139

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-11-01

140

Spatial planning of wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

NONE

2004-01-01

 
 
 
 
141

Background sound levels and wind turbine noise  

International Nuclear Information System (INIS)

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

142

The design of the Banki wind turbine and its testing in real wind conditions  

Energy Technology Data Exchange (ETDEWEB)

This paper discusses a proposed design of the Banki wind turbine based on the classical hydraulic machines theory. To evaluate that design, a 1 x 1 m prototype is experimentally investigated in real wind with and without a guiding vanes system. The turbine has a maximum power coefficient of 0.3 and a cut-in wind speed of 1.2 m/s. Furthermore, the turbine has a high starting torque and a rigid structure. These among many other interesting characteristics indicate that the turbine is suitable for water pumping and electricity generation. (Author)

Al-Maaitah, A.A. (Mu' tah Univ., Al-Karak (Jordan). Dept. of Mechanical Engineering)

1993-01-01

143

Operation and control of large wind turbines and wind farms  

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-09-01

144

Computational Aerodynamics and Aeroacoustics for Wind Turbines  

DEFF Research Database (Denmark)

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

Shen, Wen Zhong

2009-01-01

145

Lightning protection of wind turbines  

Science.gov (United States)

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

Dodd, C. W.

1982-01-01

146

Lightning protection of wind turbines  

Science.gov (United States)

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

Dodd, C. W.

1982-05-01

147

Implementation of Pitch Control Of wind Turbine Using Simulink (Matlab  

Directory of Open Access Journals (Sweden)

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

Sachin Khajuria, Jaspreet Kaur

2012-06-01

148

Wind Turbines Support Techniques during Frequency Drops — Energy Utilization Comparison  

Directory of Open Access Journals (Sweden)

Full Text Available The supportive role of wind turbines during frequency drops is still not clear enough, although there are many proposed algorithms. Most of the offered techniques make the wind turbine deviates from optimum power generation operation to special operation modes, to guarantee the availability of reasonable power support, when the system suffers frequency deviations. This paper summarizes the most dominant support algorithms and derives wind turbine power curves for each one. It also conducts a comparison from the point of view of wasted energy, with respect to optimum power generation. The authors insure the advantage of a frequency support algorithm, they previously presented, as it achieved lower amounts of wasted energy. This analysis is performed in two locations that are promising candidates for hosting wind farms in Egypt. Additionally, two different types of wind turbines from two different manufacturers are integrated. Matlab and Simulink are the implemented simulation environments.

Ayman B. Attya

2014-08-01

149

Optimization of wind turbine rotors  

Energy Technology Data Exchange (ETDEWEB)

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

Holmkvist, Jonas

1998-05-01

150

Investigation on installation of offshore wind turbines  

Science.gov (United States)

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

151

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

International Nuclear Information System (INIS)

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

152

Status of local planning for wind turbines. Vol. 1: Islands. Wind turbines - January 1997  

International Nuclear Information System (INIS)

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

153

Aeroacoustic (noise) measurements on wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-07-01

154

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

DEFF Research Database (Denmark)

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

Zhang, Yunqian; Chen, Zhe

2013-01-01

155

Aeroacoustics of large wind turbines  

Science.gov (United States)

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

Hubbard, Harvey H.; Shepherd, Kevin P.

1991-01-01

156

Seaside, mountain and... wind turbines  

International Nuclear Information System (INIS)

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

157

Towards Data-Driven Control for Modern Wind Turbines:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Houtzager, I.

2011-01-01

158

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Zhibin Ling; Simin Peng; Zhenlan Dou; Xu Cai

2013-01-01

159

Fixed pitch wind turbine control to generate the maximum power  

Science.gov (United States)

This Doctoral Thesis firstly shows the state of the art about wind power, wind turbines and alternating current generators. A part is intended for the state of the art of the commercial small wind turbines: their applications, the technology used, the elements topology according to the application type, the investigation lines in this field, the political respects that have an influence in using or not small turbines, and lastly it analyses in detail four commercial small turbines. One chapter contains the models and equations of the alternating current generators used in the Doctoral Thesis, which are the induction generator and the permanent magnets generator. Other chapter explains some methods to control the alternating current generators speed. Chapter 7 is oriented to the induction machines speed estimators. These estimators will let to eliminate the generators speed sensor. In the Thesis, some of them are simulated to test their behaviour. It presents an original analysis, which is oriented to choose the most right estimators for such an application as small wind turbines. Chapter 8 introduces the control systems developed for wind turbines. They let to extract the maximum power for every wind speed. The base of all of them is the algorithm proposed in the Thesis. Some control systems are proposed for squirrel cage induction generators and permanent magnets generators, which use voltage source and current source schemes. Some of them use generator speed sensors and others use speed estimators. The schemes do not need wind speed sensor.

Martinez Rodrigo, Fernando

160

Multilevel converters for 10 MW Wind Turbines  

DEFF Research Database (Denmark)

Several promising multi-level converter configurations for 10 MW Wind Turbines both with direct drive and one-stage gear box drive using Permanent Magnet Synchronous Generator (PMSG) are proposed, designed and compared. Reliability is a crucial indicator for large scale wind power converters, therefore the evaluations are mainly focused on the power device thermal performances, which are closely related to the life time and cost of the converter. Simulation results of different converter candidates regarding the loss and junction temperature are presented and analyzed. It is concluded that the three-level and five-level H-bridge converter topologies both have potential to achieve improved thermal performances compared to the three-level Neutral-Point-Clamped converter topology in the wind power application.

Ma, Ke; Blaabjerg, Frede

2011-01-01

 
 
 
 
161

Aerodynamic interference between two Darrieus wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

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

1981-04-01

162

Dynamic Phase Compensation of wind turbines  

DEFF Research Database (Denmark)

This paper describes a dynamic phase compensation unit for a wind turbine with directly connected induction generators. The compensation unit is based on thyristor switched capacitors, where conventional wind turbine compensations use mechanical contactors to switch the capacitors. The unit modules are tested and simulated, and preliminary studies on the impact on power quality are performed.

Soerensen, P.; Skaarup, J.

2004-01-01

163

When wind turbines go to the sea  

International Nuclear Information System (INIS)

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

164

Superconductivity for Large Scale Wind Turbines  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-10-12

165

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-03-15

166

Wind turbine blade health monitoring using acoustic beamforming techniques.  

Science.gov (United States)

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

167

Aerodynamics of Wind Turbines : second edition  

DEFF Research Database (Denmark)

Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its second edition, it has been entirely updated and substantially extended to reflect advances in technology, research into rotor aerodynamics and the structural response of the wind turbine structure. Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element Momentum method is also covered, as are eigenmodes and the dynamic behavior of a turbine. The new material includes a description of the effects of the dynamics and how this can be modeled in an aeroelastic code, which is widely used in the design and verification of modern wind turbines. Further, the description of how to calculate the vibration of the whole construction as well as the time varying loads has been substantially updated. This is the essential reference for both engineering students and others with a professional or academic interest in the physics and technologies behind horizontal axis wind turbines.

Hansen, Martin Otto Laver

2008-01-01

168

Design and development of direct drive generators for wind turbines  

International Nuclear Information System (INIS)

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

169

Turbulent flow simulation over ice-accreted wind turbine blades  

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-07-01

170

Power Control Design for Variable-Speed Wind Turbines  

Directory of Open Access Journals (Sweden)

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

Francesc Pozo

2012-08-01

171

Smart structure for small wind turbine blade  

Science.gov (United States)

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

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

2013-08-01

172

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

DEFF Research Database (Denmark)

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. However, new challenges appear for such topology, which have to be properly identified and successfully overcome. This paper presents possible concept for transformer-less wind turbine topology along with an overview of most promising candidates for optimal full-scale power converter design. Study is carried with proposed and justified high voltage wind turbine application along with selection of existing and most promising multilevel power converter topologies, which could be successfully proposed for transformer-less wind turbines.

Sztykiel, Michal

2011-01-01

173

Wind Turbine Converter Control Interaction with Complex Wind Farm Systems  

DEFF Research Database (Denmark)

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

Kocewiak, Lukasz Hubert; Hjerrild, Jesper

2013-01-01

174

Illustration of modern wind turbine ancillary services  

Energy Technology Data Exchange (ETDEWEB)

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

Margaris, I. D.; Hatziargyriou, N. D. [National Technical University of Athens, School of Electrical and Computer Eng. Electric Energy Systems Lab, Iroon Polytechniou 9, 15780 Athens (Greece); Hansen, A. D.; Sorensen, P. [Riso National Laboratory for Sustainable Energy, Technical University of Denmark, Wind Energy Division, P.O. Box 49, DK-4000 Roskilde (Denmark); Hatziargyriou, N. D. [Public Power Corporation S.A. Athens (Greece)

2010-06-15

175

Meteorological aspects of siting large wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

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

1981-01-01

176

Energies | Special Issue : Wind Turbines 2014  

... Numerical analyses are performed to estimate the performances of the proposed configuration by means of the commercial code COMSOL Multiphysics&174 with respect to Savonius wind turbine with overlap only. Parametric analyses are performed, for a fixed overlap ratio, by varying the slot position; the results show that for slot positioned near the blade root, the Savonius rotor improves performances at low tip speed ratio, evidencing a better starting torque. This circumstance is confirmed by static analyses performed on the slotted blades in order to investigate the starting ...

177

Flicker emission levels from wind turbines  

International Nuclear Information System (INIS)

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

178

Offshore wind turbines reliability, availability and maintenance  

CERN Document Server

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

Tavner, Peter

2012-01-01

179

Challenges for large wind turbine blades  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Ho?yland, Jo?rg

2010-01-01

180

Model Predictive Control of Wind Turbines  

DEFF Research Database (Denmark)

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

Henriksen, Lars Christian

2011-01-01

 
 
 
 
181

Floating wind turbines and their associated risks  

Energy Technology Data Exchange (ETDEWEB)

Sgurr energy is a leading independent engineering consultancy that deals with hydro, wind, wave and tidal, solar and bio-energy related projects. The aim of this paper is to present floating wind turbines and the risks associated with them. Floating wind turbines are stronger than conventional turbines and have more consistent winds, reduced visual impact, fewer environmental constraints and can be mass-produced and assembled close to the shore. Types of floating turbine include tension leg platform (TLP), spar buoy, and semi-submersible. A comparison between the designs of the various types is discussed briefly. Failures related to turbines and floating platforms are instanced and the risks and concerns, from the designer's point of view, are detailed. Some examples of failures are described and explained. The paper concludes that it is understood that there is no single optimal platform design; every type of platform has its own advantages and disadvantages and catastrophic failure is considered doubtful.

Briggs, Charles; Capaldo, Michael [Sgurr Energy (Canada)

2011-07-01

182

Proposal of law adopted by the Senate relative to the layout of wind turbines and to the protection of environment; Proposition de loi adoptee par le Senat relative a l'implantation des eoliennes et a la protection de l'environnement  

Energy Technology Data Exchange (ETDEWEB)

This document concerns the modifications given by the French Senate to the proposal of law concerning the layout of wind turbines and their aesthetical impact on the environment. The modifications concern: the construction permit for wind turbines, the preliminary impact study, and the financial warranties for the restoration of the site at the end of the exploitation. (J.S.)

NONE

2002-10-01

183

European wind turbine standards 2 (EWTS-2)  

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-03-01

184

Active load control techniques for wind turbines.  

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-07-01

185

Wind response characteristics of horizontal axis wind turbines  

Science.gov (United States)

It was the objective of the work reported here, and in the companion paper 1 . A broader examination of wind turbine dynamic response to turbulence, and attempts to ascertain the features of turbulence that wind turbines are most sensitive to were made. A statistical description of the wind input including all three wind components and allowing linear wind gradients across the rotor disk, was used together with quasi-static aerodynamic theory and an elementary structural model involving only a few degrees of freedom. The idea was to keep the turbine model simple and show the benefits of this type of statistical wind representation before attempting to use a more complex turbine model. As far as possible, the analysis was kept in the simplest form, while still preserving key physical responses.

Thresher, R. W.; Holley, W. E.; Jafarey, N.

1981-01-01

186

A Benchmark Evaluation of Fault Tolerant Wind Turbine Control Concepts  

DEFF Research Database (Denmark)

As the world’s power supply to a larger and larger degree depends on wind turbines, it is consequently and increasingly important that these are as reliable and available as possible. Modern fault tolerant control (FTC) could play a substantial part in increasing reliability of modern wind turbines. A benchmark model for wind turbine fault detection and isolation, and FTC has previously been proposed. Based on this benchmark, an international competition on wind turbine FTC was announced. In this brief, the top three solutions from that competition are presented and evaluated. The analysis shows that all three methods and, in particular, the winner of the competition shows potential for wind turbine FTC. In addition to showing good performance, the approach is based on a method, which is relevant for industrial usage. It is based on a virtual sensor and actuator strategy, in which the fault accommodation is handled in software sensor and actuator blocks. This means that the wind turbine controller can continue operation as in the fault free case. The other two evaluated solutions show some potential but probably need improvements before industrial applications.

Odgaard, Peter Fogh; Stoustrup, Jakob

2014-01-01

187

Basic rotor aerodynamics applied to wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

Hansen, M.O.L.

1998-01-01

188

Model of wind shear conditional on turbulence and its impact on wind turbine loads  

DEFF Research Database (Denmark)

We analyse high-frequency wind velocity measurements from two test stations over a period of several years and at heights ranging from 60 to 200 m, with the objective to validate wind shear predictions as used in load simulations for wind turbine design. A validated wind shear model is thereby proposed for flat terrain and that can significantly decrease the uncertainty associated with fatigue load predictions for wind turbines with large rotors. An essential contribution is the conditioning of wind shear on the 90% quantile of wind turbulence, such that the appropriate magnitude of the design fatigue load is achieved. The proposed wind shear model based on the wind measurements is thereby probabilistic in definition, with shear jointly distributed with wind turbulence. A simplified model for the wind shear exponent is further derived from the full stochastic model. The fatigue loads over different turbine components are evaluated under the full wind measurements, using the developed wind shear model and withstandard wind conditions prescribed in the IEC 61400-1 ed. 3. The results display the effect of the Wöhler exponent and reveal that under moderate turbulence, the effect of wind shear is most pronounced on the blade flap loads. It is further shown that under moderate wind turbulence, the wind shear exponents may be over-specified in the design standards, and a reduction of wind shear exponent based on the present measurements can contribute to reduced fatigue damage equivalent loads on turbine blades. Although the influence of wind shear on extreme loads was found to be negligible, the IEC 61400-1 wind shear definition was found to result in non-conservative estimates of the 50 year extreme blade deflection toward the tower, especially under extreme turbulence conditions. Copyright © 2014 John Wiley & Sons, Ltd.

Dimitrov, Nikolay Krasimirov; Natarajan, Anand

2014-01-01

189

Increasing the Efficiency of Grid Tied Micro Wind Turbines in Low Wind Speed Regimes  

Directory of Open Access Journals (Sweden)

Full Text Available Major problem with grid tied micro wind turbine is synchronization and wind variability. Due to this problem the stability of available grid gets reduced. The stability can be achieved by output power control of the turbine. Major part of many countries like India, the annual mean wind speed is not high. The rated wind speed of turbine remain around 11 m/s and cut in is around 3.5 m/s. Due to this problem we aimed to develop a sustainable wind energy system that can provide stable power supply even at the locations of low wind speed of 2 - 4 m/s. To address this issue, a momentary impulse or external torque to the rotor by external motor is one of the good options to maintain the momentum of blades and thus provide stability for sufficient time. Various theoretical calculations and experiments are conducted on the above method. This would increase the output power and also the efficiency of wind turbine. We show that Return-On-Investment will be high as compared with other grid connected turbines. Our proposed concept in the present study, if implemented properly, can help the installation of number of wind turbines even at domestic level. It also makes the consumers energy independent and promotes the use of wind as a source of energy and may enter as a rooftop energy supply system similar to solar.

Kshitij Tiwari

2014-10-01

190

Study on wind turbine arrangement for offshore wind farms  

DEFF Research Database (Denmark)

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

Shen, Wen Zhong; Mikkelsen, Robert Flemming

2011-01-01

191

Optimization of Wind Turbine Airfoils/Blades and Wind Farm Layouts  

Science.gov (United States)

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

Chen, Xiaomin

192

Airfoil characteristics for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-03-01

193

Structured Control of LPV Systems with Application to Wind Turbines  

DEFF Research Database (Denmark)

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

Adegas, Fabiano Daher; Stoustrup, Jakob

2012-01-01

194

Aeroelastic instability problems for wind turbines  

DEFF Research Database (Denmark)

This paper deals with the aeroelostic instabilities that have occurred and may still occur for modem commercial wind turbines: stall-induced vibrations for stall-turbines, and classical flutter for pitch-regulated turbines. A review of previous works is combined with derivations of analytical stability limits for typical blade sections that show the fundamental mechanisms of these instabilities. The risk of stall-induced vibrations is mainly related to blade airfoil characteristics, effective direction of blade vibrations and structural damping, whereas the blade tip speed, torsional blade stiffness and chordwise position of the center of gravity along the blades are the main parameters for flutter. These instability characteristics are exemplified by aeroelastic stability analyses of different wind turbines. The review of each aeroelastic instability ends with a list of current research issues that represent unsolved aeroelostic instability problems for wind turbines. Copyright (c) 2007 John Wiley & Sons, Ltd.

Hansen, Morten Hartvig

2007-01-01

195

Forecast and Performance of Wind Turbines  

Directory of Open Access Journals (Sweden)

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

T. Ahilan

2012-01-01

196

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

Energy Technology Data Exchange (ETDEWEB)

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

Halkema, J.A.

2000-04-01

197

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

Directory of Open Access Journals (Sweden)

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

Farshad Dastyar

2012-07-01

198

Advances in wind turbine blade design and materials  

DEFF Research Database (Denmark)

Wind energy is gaining critical ground in the area of renewable energy, with wind energy being predicted to provide up to 8% of the world’s consumption of electricity by 2021. Advances in wind turbine blade design and materials reviews the design and functionality of wind turbine rotor blades as well as the requirements and challenges for composite materials used in both current and future designs of wind turbine blades. Part one outlines the challenges and developments in wind turbine blade design, including aerodynamic and aeroelastic design features, fatigue loads on wind turbine blades, and characteristics of wind turbine blade airfoils. Part two discusses the fatigue behavior of composite wind turbine blades, including the micromechanical modelling and fatigue life prediction of wind turbine blade composite materials, and the effects of resin and reinforcement variations on the fatigue resistance of wind turbine blades. The final part of the book describes advances in wind turbine blade materials, development and testing, including biobased composites, surface protection and coatings, structural performance testing and the design, manufacture and testing of small wind turbine blades. Advances in wind turbine blade design and materials offers a comprehensive review of the recent advances and challenges encountered in wind turbine blade materials and design, and will provide an invaluable reference for researchers and innovators in the field of wind energy production, including materials scientists and engineers, wind turbine blade manufacturers and maintenance technicians, scientists, researchers and academics.

2013-01-01

199

Mobile measurement system for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

Kildemoes Moeller, T.

1997-06-01

200

Stochastic Modeling Of Wind Turbine Drivetrain Components  

DEFF Research Database (Denmark)

Cost reduction is a substantial requirement for wind turbines to become competitive compared to other energy supply techniques. For offshore wind turbines the costs for Operation and Maintenance (OM) are significant. One of the reasons for the high OM costs is unplanned repair, and therefore reliable components are needed for wind turbine. In this paper focus is on reliability of critical components in drivetrain such as bearings and shafts. High failure rates of these components imply a need for more reliable components. To estimate the reliability of these components, stochastic models are needed for initial defects and damage accumulation. In this paper, stochastic models are formulated considering some of the failure modes observed in these components. The models are based on theoretical considerations, manufacturing uncertainties, size effects of different scales. It is illustrated how the stochastic models can be used to obtain estimates of failure rates for wind turbine components.

Rafsanjani, Hesam Mirzaei; SØrensen, John Dalsgaard

2014-01-01

 
 
 
 
201

Vertical Axis Wind Turbine Foundation parameter study  

Energy Technology Data Exchange (ETDEWEB)

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

Lodde, P.F.

1980-07-01

202

Assessment of tonal noise from wind turbines  

International Nuclear Information System (INIS)

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

203

Investigation of Wind Turbine Rotor Concepts for Offshore Wind Farms  

Science.gov (United States)

Current plans in offshore wind energy developments call for further reduction of cost of energy. In order to contribute to this goal, several wind turbine rotor concepts have been investigated. Assuming the future offshore wind turbines will operate only in the offshore wind farms, the rotor concepts are not only evaluated for their stand-alone performances and their potential in reducing the loads, but also for their performance in an offshore wind farm. In order to do that, the 10MW reference wind turbine designed in Innwind.EU project is chosen as baseline. Several rotor parameters have been modified and their influences are investigated for offshore wind turbine design purposes. This investigation is carried out as a conceptual parametrical study. All concepts are evaluated numerically with BOT (Blade optimisation tool) software in wind turbine level and with Farmflow software in wind farm level for two wind farm layouts. At the end, all these concepts are compared with each other in terms of their advantages and disadvantages.

Ceyhan, Özlem; Grasso, Francesco

2014-06-01

204

Reliability of Wind Turbine Components-Solder Elements Fatigue Failure  

DEFF Research Database (Denmark)

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

Kostandyan, Erik; SØrensen, John Dalsgaard

2012-01-01

205

Available and announced offshore wind turbines  

International Nuclear Information System (INIS)

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

206

Aerodynamical noise from wind turbine generators  

International Nuclear Information System (INIS)

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

207

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

Energy Technology Data Exchange (ETDEWEB)

This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers to wind energy expansion by providing independent testing results for small wind turbines (SWT). In total, four turbines were tested at the National Wind Technology Center (NWTC) as a part of this project. Safety and function testing is one of up to five tests performed on the turbines, including power performance, duration, noise, and power-quality tests. The results of the testing provide the manufacturers with reports that can be used for small wind turbine certification. The test equipment includes a Gaia-Wind 11-kW wind turbine mounted on an 18-m monopole tower. Gaia-Wind Ltd. manufactured the turbine in Denmark. The system was installed by the NWTC site operations group with guidance and assistance from Gaia-Wind.

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

2010-01-01

208

Modeling stochastic wind loads on vertical axis wind turbines  

Science.gov (United States)

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

Veers, P. S.

209

Preliminary wind tunnel tests on the pedal wind turbine  

Science.gov (United States)

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

Vinayagalingam, T.

1980-06-01

210

Assessment of wind turbine load measurement instrumentation  

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-03-01

211

Optimal Control of Floating Offshore Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Floating Offshore Wind Power is an emerging and promising technology that is particularly interesting from a Norwegian point of view because of our long and windy coast. There are however still several remaining challenges with this technology and one of them is a possible stability problem due to positive feedback from tilt motion of the turbine tower. The focus of this report is to develope a simulator for a floating offshore wind turbine that includes individual, vibrating blades. Se...

Lindeberg, Eivind

2009-01-01

212

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-07-01

213

Lift Augmentation for Vertical Axis Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The concept of harnessing wind power has been around for centuries, and is first recorded by the Persians in 900 AD. These early uses of wind power were for the processing of food, particularly grinding grains, and consisted of stationary blades around a horizontal axis, the precursor to today’s horizontal axis wind turbines (HAWT). Technology for these wind mills was essentially the same until the 1930’s when advances in aircraft propeller theories were applied to the blades of the turbi...

Angle Ii, Gerald M.; Mary Ann Clarke

2010-01-01

214

Slotted Blades Savonius Wind Turbine Analysis by CFD  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

215

Preliminary modelling study of ice accretion on wind turbines  

DEFF Research Database (Denmark)

One of the main challenges associated with cold-climate wind energy is icing on wind turbines and a series of icing-induced problems such as production loss, blade fatigue and safety issues. Because of the difficulties with on-site measurements, simulations are often used to understand and predict icing events. In this paper, a new methodology for prediction of icing-induced production loss is proposed, from which the fundamentals of ice accretion on wind turbines can be better understood and the operational production losses can be more reliably predicted. Computational fluid dynamics (CFD) modelling of ice accretion on wind turbines is also performed for different ice events, resulting in a reliable framework for CFD-based ice accretion modelling which is one of the key elements in the new methodology.

Pedersen, Marie Cecilie; Yin, Chungen

2014-01-01

216

Site-optimization of wind turbine generators  

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-12-31

217

Computational aerodynamics and aeroacoustics for wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The present thesis consists of 19 selected papers dealing with the development and use of CFD methods for studying the aerodynamics and aero-acoustics of wind turbines. The papers are written in the period from 1997 to 2008 and numbered according to the list in page v. The work consists of two parts: an aerodynamic part based on Computational Fluid Dynamics and an aero-acoustic part based on Computational Aero Acoustics for wind turbines. The main objective of the research was to develop new computational tools and techniques for analysing flows about wind turbines. A few papers deal with applications of Blade Element Momentum (BEM) theory to wind turbines. In most cases the incompressible Navier-Stokes equations in primitive variables (velocity-pressure formulation) are employed as the basic governing equations. However, since fluid mechanical problems essentially are governed by vortex dynamics, it is sometimes advantageous to use the concept of vorticity (defined as the curl of velocity). In vorticity form the Navier-Stokes equations may be formulated in different ways, using a vorticity-stream function formulation, a vorticity-velocity formulation or a vorticity-potential-stream function formulation. In [1] - [3] two different vorticity formulations were developed for 2D and 3D wind turbine flows. In [4] and [5] numerical techniques for avoiding pressure oscillations were developed when solving the velocity-pressure coupling system in the in-house EllipSys2D/3D code. In [6] - [8] different actuator disc techniques combined with CFD are presented. This includes actuator disc, actuator line and actuator surface techniques, which were developed to simulate flows past one or more wind turbines. In [9] and [10] a tip loss correction method that improves the conventional models was developed for use in combination with BEM or actuator/Navier-Stokes computations. A simple and efficient technique for determining the angle of attack for flow past a wind turbine rotor was developed in [11], and in [12] tunnel wall corrections for wind tunnels with closed or open test sections were developed. The second part of the thesis deals with Computational Aero-Acoustics (CAA). With the spread of wind turbines near urban areas, there is an increasing need for accurate predictions of aerodynamically generated noise. Indeed, noise has become one of the most important issues for further development of wind power, and the iv Wen Zhong Shen ability of controlling and minimising noise emission may be advantageous when competing on the world energy market. To predict generation and propagation of aerodynamic noise, it is required to solve the compressible Navier-Stokes equations. As the scales of the flow and the acoustic waves are quite different (about 1/M, M=Mach number=Uinfinity/c), it is difficult to resolve them together at the same time. Hardin and Pope proposed a non-linear two-step (viscous incompressible flow and inviscid acoustic perturbation) splitting procedure for computational aero-acoustics that is suitable for both generation and propagation. The advantage of the splitting approach, as compared to the acoustic analogies, is that the source strength is obtained directly and that it accounts for sound radiation as well as scattering. In [13] and [14] an inconsistency in the original formulation of Hardin and Pope 1994 was analysed and a consistent formulation was proposed and applied to laminar flows. An aero-acoustic formulation for turbulent flows was in [15] developed for Large Eddy Simulation (LES), Unsteady Reynolds Averaged Navier-Stokes Simulation (URANS) and Detached Eddy Simulation (DES). In [16] a collocated grid / finite volume method for aero-acoustic computations was developed and implemented in the EllipSys2D/3D code. In [17] and [18] three dimensional flowacoustic computations were carried out. Finally, the aero-acoustic formulation using high order Finite Difference schemes (Dispersion Relation Preserving (DRP) / Optimized Compact schemes) was developed in [19] and implemented in the EllipSys2D/3D code. (LN)

Shen, W.Z.

2009-10-15

218

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

Science.gov (United States)

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

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

2012-03-01

219

Wind turbine SCADA alarm analysis for improving reliability.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2012-01-01

220

Wind turbines turbulence effects on cable structures in their vicinity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Actual wind turbines size can be as large as 80 meters diameter (1 MW and over). Behind the wind turbines, mean wind speed is sensibly reduced (approximately 50%) and turbulence severely increased. The spectral density power of disturbed wind can be assumed similar to classical wind but centred on the rotational speed of the motor. Due to classical speed and shape of wind turbine, corresponding key frequency for disturbed wind is close to one Hz. Any structure in the vicinity of wind t...

Lilien, Jean-louis; Keutgen, Renaud; Raimarckers, Nicolas

2001-01-01

 
 
 
 
221

Behavior of bats at wind turbines  

Science.gov (United States)

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

222

Behavior of bats at wind turbines.  

Science.gov (United States)

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

223

A Method for Modeling of Floating Vertical Axis Wind Turbine  

DEFF Research Database (Denmark)

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

Hansen, Martin Otto Laver

2013-01-01

224

Innovative multi rotor wind turbine designs  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-07-01

225

Design Oriented Aerodynamic Modelling of Wind Turbine Performance  

Energy Technology Data Exchange (ETDEWEB)

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

Greco, Luca; Testa, Claudio; Salvatore, Francesco [INSEAN, Via di Vallerano, 00128 Rome (Italy)]. E-mail: f.salvatore@insean.it

2007-07-15

226

Analysis of Counter-Rotating Wind Turbines  

International Nuclear Information System (INIS)

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

227

Load prediction of stall regulated wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-12-01

228

Power electronics for modern wind turbines  

CERN Document Server

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

Blaabjerg, Frede

2006-01-01

229

Infrasound emission generated by wind turbines  

Science.gov (United States)

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

Ceranna, Lars; Pilger, Christoph

2014-05-01

230

Jet spoiler arrangement for wind turbine  

Science.gov (United States)

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

231

Slotted Blades Savonius Wind Turbine Analysis by CFD  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper a new bucket configuration for a Savonius wind generator is proposed. Numerical analyses are performed to estimate the performances of the proposed configuration by means of the commercial code COMSOL Multiphysics® with respect to Savonius wind turbine with overlap only. Parametric analyses are performed, for a fixed overlap ratio, by varying the slot position; the results show that for slot positioned near the blade root, the Savonius rotor improves performances at low tip speed ratio, evidencing a better starting torque. This circumstance is confirmed by static analyses performed on the slotted blades in order to investigate the starting characteristic of the proposed Savonius wind generator configuration.

Andrea Alaimo

2013-12-01

232

RELIABILITY OF MACHINE ELEMENTS IN WIND TURBINES  

Directory of Open Access Journals (Sweden)

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

Willi GRUENDER

2010-06-01

233

Vertical axis wind turbine control strategy  

Energy Technology Data Exchange (ETDEWEB)

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

McNerney, G.M.

1981-08-01

234

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

Science.gov (United States)

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

Wu, Yu-Ting; Porté-Agel, Fernando

2014-05-01

235

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

Science.gov (United States)

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

Yang, Xiaolei; Kang, Seokkoo; Sotiropoulos, Fotis

2012-11-01

236

Wind Turbine Test Wind Matic WM 15S  

DEFF Research Database (Denmark)

The report describes standard measurements performed on a Wind-Matic WM 15S, 55 kW wind turbine. The measurements carried out and reported here comprises the power output, system efficiency, energy production, transmission efficiency, rotor power, rotor efficiency, air-brakes efficiency, dynamical behaviour of the turbine, loads at cut-in and braking, rotor torque at stopped condition, and noise emission.

Friis Pedersen, Troels

1986-01-01

237

Wind turbulence inputs for horizontal axis wind turbines  

Science.gov (United States)

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

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

1981-01-01

238

Wind turbines - localisation strategy in Denmark  

International Nuclear Information System (INIS)

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

239

Tjæreborg Wind Turbine : 4. dynamic inflow measurement  

DEFF Research Database (Denmark)

This paper presents results from the fourth measurement camapign at the Tjæreborg (Tjaereborg) WInd Turbine during operation with stepwise pitch angle changes. The measurements cover one hour of operation at wind speeds between 7 and 10 m/s aceraging approximately 8.7 m/s.

Øye, Stig

1991-01-01

240

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

International Nuclear Information System (INIS)

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

 
 
 
 
241

Wind power turbine design, selection, and optimization  

CERN Document Server

Wind power is the most mature technology of the major sources of renewable energy that have been developed, and more efficient and cost-effective techologies and materials are constantly being sought for turbines and the equipment used on them.  Here is a comprehensive and thorough review of the engineering pros and cons for using different kinds of wind turbines in different areas, including offshore.  With a full technical knowledge, engineers, managers, and other decision-makers in the wind energy industry can make more informed decisions about increasing capacity, cost-efficiency, and lon

Lyatkher, Victor

2013-01-01

242

Review paper on wind turbine aerodynamics  

DEFF Research Database (Denmark)

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

Hansen, Martin Otto Laver; Aagaard Madsen, Helge

2011-01-01

243

Computer control for remote wind turbine operation  

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-12-31

244

Wind Turbine Micropitting Workshop: A Recap  

Energy Technology Data Exchange (ETDEWEB)

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

Sheng, S.

2010-02-01

245

A review of wind turbine noise  

Energy Technology Data Exchange (ETDEWEB)

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

Klug, H. [DEWI Wilhelmshaven (Germany)

2006-08-15

246

UNSTEADY SIMULATION OF FLOW IN MICRO VERTICAL AXIS WIND TURBINE  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2010-01-01

247

Power Electronics for the Next Generation Wind Turbine System  

DEFF Research Database (Denmark)

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

Ma, Ke

2013-01-01

248

Robust Utilization of Wind Turbine Flexibility for Grid Stabilization  

DEFF Research Database (Denmark)

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

Juelsgaard, Morten; Bendtsen, Jan Dimon

2012-01-01

249

A neuro-fuzzy controlling algorithm for wind turbine  

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-12-31

250

Grid impact of variable-speed wind turbines  

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-03-01

251

Observer Backstepping Control for Variable Speed Wind Turbine  

DEFF Research Database (Denmark)

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

Galeazzi, Roberto; Gryning, Mikkel Peter Sidoroff

2013-01-01

252

Development of Intelligent Wind Turbine Generator with Tandem Wind Rotors and Double Rotational Armatures  

Science.gov (United States)

This paper proposes the superior wind turbine generator, which is composed of the tandem wind rotors and the double rotational armature type generator without the conventional stator. The large-sized front wind rotor and the small-sized rear wind rotor drive respectively the inner and the outer armatures of the generator, in keeping the rotational torque counter-balanced. Such operating conditions enable to make the output higher than the conventional wind turbine and to keep the output constant in the rated operating mode without using the brake and/or the pitch control mechanisms. Such wonderful advantages in the generating mode are discussed and verified experimentally with the model turbine generator.

Kanemoto, Toshiaki; Galal, Ahmed Mohamed

253

Aspects in Formulating Mathematical Model of Wind Turbine  

Directory of Open Access Journals (Sweden)

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

Waleed Khalil Ahmed

2013-06-01

254

Pitch control system for large-scale wind turbines  

Science.gov (United States)

The purpose of this analysis is to study the design of a pitching blade segment control system for the NASA-DOE MOD 0 wind turbine to alleviate some of the problems associated with shear, tower shadow, and gravity phenomena, such as shortened lifetime and noise generation. The classical linear quadratic Gaussian optimal regulator approach is used in the control formulation. A quasisteady aerodynamic analysis incorporating wind shear and tower shadow is utilized. An equivalent hinge model describes the turbine structural dynamics. The study shows that the proposed control system can provide significant vibration and noise reductions as well as a cleaner power signal, better gust response, and increased annual energy output.

Liebst, B. S.

1983-04-01

255

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

Science.gov (United States)

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

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

2014-01-01

256

Defect distribution and reliability assessment of wind turbine blades  

DEFF Research Database (Denmark)

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

Branner, Kim; Berring, Peter

2011-01-01

257

Defect Distribution and Reliability Assessment of Wind Turbine Blades  

DEFF Research Database (Denmark)

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

Toft, Henrik Stensgaard; Branner, Kim

2011-01-01

258

Aeroelastic analysis of a troposkien-type wind turbine blade  

Science.gov (United States)

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

Nitzsche, F.

1981-01-01

259

Optimal Excitation Controller Design for Wind Turbine Generator  

Directory of Open Access Journals (Sweden)

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

A. K. Boglou

2011-01-01

260

Assessment and prediction of wind turbine noise  

International Nuclear Information System (INIS)

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

 
 
 
 
261

Wind Turbine Test. Wind Matic WM 17S  

DEFF Research Database (Denmark)

The report describes standard measurements performed on a Wind-Matic WM 17S, 75 kW wind turbine. The measurements carried out and reported here comprises the power output, system efficiency, energy production, transmission efficiency, rotor power, rotor efficiency, air-brakes efficiency, structural dynamics, loads at cut-in and braking, rotor torque at stopped condition, and noise emission.

Friis Pedersen, Troels

1986-01-01

262

Thermal Performance of Wind Turbine Power System's Engine Room  

Science.gov (United States)

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

263

Performance of spanish wind turbines  

International Nuclear Information System (INIS)

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

264

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-05-01

265

Stochastic wind turbine control in multiblade coordinates  

DEFF Research Database (Denmark)

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

Thomsen, Sven Creutz; Niemann, Hans Henrik

2010-01-01

266

Structural Reliability Aspects in Design of Wind Turbines  

DEFF Research Database (Denmark)

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

SØrensen, John Dalsgaard

2007-01-01

267

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-08-01

268

Enhanced wind turbine noise prediction tool SILANT  

International Nuclear Information System (INIS)

influencing refraction and ground effects. Prediction results are compared to SIROCCO project measurements from microphones positioned in a circle around a turbine. The high spatial and temporal resolution of the SILANT simulations gives new insights in the variation of wind turbine inflow and trailing edge noise as a function of observer position, rotor azimuth angle and frequency band. The influence of directivity is illustrated for the dominant noise sources.

269

Shoosing the appropriate size wind turbine  

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-12-31

270

Resonant vibration control of wind turbine blades  

DEFF Research Database (Denmark)

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

Svendsen, Martin Nymann Technical University of Denmark,

2010-01-01

271

Methods of making wind turbine rotor blades  

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-04-01

272

Feasibility of monitoring large wind turbines using photogrammetry  

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-12-15

273

Numerical Simulations of a Roof-Top Wind Turbine  

Science.gov (United States)

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

Moayedian, Shahab; Rahai, Hamid

2010-11-01

274

OUT Success Stories: Advanced Airfoils for Wind Turbines  

International Nuclear Information System (INIS)

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

275

Magnus wind turbines as an alternative to the blade ones  

Science.gov (United States)

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

276

Magnus wind turbines as an alternative to the blade ones  

International Nuclear Information System (INIS)

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

277

(Wind turbine). Final quarterly project report, January-April 1981  

Energy Technology Data Exchange (ETDEWEB)

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. (LEW)

Racine, W.D. III

1981-04-30

278

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

DEFF Research Database (Denmark)

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

Zhao, B.; Li, H.

2011-01-01

279

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-04-15

280

Aerodynamic analysis of rotor-nacelle interactions for wind turbines  

International Nuclear Information System (INIS)

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

 
 
 
 
281

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

Directory of Open Access Journals (Sweden)

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

K. K. M. S. Kariyawasam

2013-06-01

282

Comparative Study of Voltage Recovery Behaviors of Grid-Connected Wind Turbines  

DEFF Research Database (Denmark)

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 re-established with minimized power losses. This paper concentrates on voltage recovery of variable speed wind turbines. The models of two different kinds of variable speed wind turbines, respectively with slip control and with doubly fed induction generator (DFIG), are developed in PSCAD/EMTDC. In both wind power generation systems, control strategies are proposed to re-establish the wind turbine terminal voltage after the clearance of an external short-circuit fault, which have been demonstrated by simulation results.

Sun, Tao; Chen, Zhe

2004-01-01

283

Aileron controls for wind turbine applications  

Science.gov (United States)

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

284

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

DEFF Research Database (Denmark)

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

Li, H.; Zhao, B.

2011-01-01

285

Impact of wind turbines on birdlife  

International Nuclear Information System (INIS)

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

286

Two LQRI based Blade Pitch Controls for Wind Turbines  

Directory of Open Access Journals (Sweden)

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

Sungsu Park

2012-06-01

287

Aerodynamic performance prediction of horizontal axis wind turbines  

Science.gov (United States)

A new method for calculating the aerodynamic performance of horizontal axis wind turbines is described. The method, entitled the helical vortex method, directly calculates the local induced velocity due to helical vortices that originate at the rotor blade. Furthermore, the method does not require a specified circulation distribution. Results of the method are compared to similar results obtained from Wilson PROP code methods as well as to existing experimental data taken from a Mod-O wind turbine. It is shown that results of the proposed method agree well with experimental values of the power output both near cut-in and at rated wind speeds. Further, it is found that the method does not experience some of the numerical difficulties encountered by the PROP code when run at low wind velocities.

Jeng, D. R.; Keith, T. G.; Aliakbarkhanafjeh, A.

1981-01-01

288

Modelling and Analysis of DFIG Wind Turbine Harmonics Generated in Grids  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper an analytic technique for modelling harmonics is proposed for a DFIG wind turbine connected to the grid. An algorithm based on Hilbert transform for the analysis of harmonics in power systems isdeveloped. The simulation results prove the effectiveness of the Hilbert Transform (HT for power harmonic analysis in DFIG wind turbine connected to a grid.

A.Chilambuchelvan

2010-06-01

289

Electrical Aspects of Wind Turbines  

DEFF Research Database (Denmark)

This is the most authoritative single volume on offshore wind power yet published. Distinguished experts, mainly from Europe's leading universities, have contributed a collection of peer reviewed papers on the interfaces between wind power technology and marine engineering. The range of issues covered by the book include: wind as a resource; wind power generation; connection to the grid; the marine environment and engineering issues particular to it. This book is essential for academic departments of mechanical engineering/energy engineering/ renewable energy. Offshore wind power generation will be the driver of the offshore industry for the foreseeable future: all organisations involved in offshore engineering should have this book.

Chen, Zhe; Blaabjerg, Frede

2009-01-01

290

Light hindrance by wind turbines. Schaduwhinder door windmolens  

Energy Technology Data Exchange (ETDEWEB)

The application of wind turbines in build up areas generates noise and optical problems for its environment. The optical problems connected with wind turbines, e.g. the shadows generated by the wind turbine blades and its effect on human population, are described.

Verkuijlen, E.

1983-01-01

291

Lift Augmentation for Vertical Axis Wind Turbines  

Directory of Open Access Journals (Sweden)

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

Gerald M Angle II

2010-12-01

292

Structured Linear Parameter Varying Control of Wind Turbines  

DEFF Research Database (Denmark)

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

Adegas, Fabiano Daher; Sloth, Christoffer

2012-01-01

293

Damping Wind and Wave Loads on a Floating Wind Turbine  

DEFF Research Database (Denmark)

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

Christiansen, SØren; Bak, Thomas

2013-01-01

294

Damping Wind and Wave Loads on a Floating Wind Turbine  

Directory of Open Access Journals (Sweden)

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

Torben Knudsen

2013-08-01

295

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

DEFF Research Database (Denmark)

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

Barahona Garzón, Braulio

2012-01-01

296

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2001-01-01

297

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-05-01

298

A geographic analysis of wind turbine placement in Northern California  

International Nuclear Information System (INIS)

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

299

Mother Nature inspires new wind turbine wing  

DEFF Research Database (Denmark)

The sight of a bird of prey hanging immobile in the air while its wings continuously adjust themselves slightly in relation to the wind in order to keep the bird in the same position in the air, is a sight that most of us have admired, including the windenergy scientists at Risø DTU. They have started transferring the principle to wind turbine blades to make them adaptive

SØnderberg Petersen, L.

2007-01-01

300

Wind turbine pitch control using ICPSO-PID algorithm  

DEFF Research Database (Denmark)

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

Shen, Wen Zhong

2013-01-01

 
 
 
 
301

PowerJet Wind Turbine Project  

Energy Technology Data Exchange (ETDEWEB)

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

Bartlett, Raymond J

2008-11-30

302

Individual Pitch Control for Mitigation of Power Fluctuation of Variable Speed Wind Turbines  

DEFF Research Database (Denmark)

Grid connected wind turbines are the sources of power fluctuations during continuous operation due to wind speed variation, wind shear and tower shadow effects. This paper presents an individual pitch control (IPC) strategy to mitigate the wind turbine power fluctuation at both above and below the rated wind speed conditions. Three pitch angles are adjusted separately according to the generator output power and the azimuth angle of the wind turbine. The IPC strategy scheme is proposed and the individual pitch controller is designed. The simulations are performed on the NREL (National Renewable Energy Laboratory) 1.5MW upwind reference wind turbine model. The simulation results are presented and discussed to show the validity of the proposed control method.

Zhang, Yunqian; Hu, Weihao

2012-01-01

303

Noise measurements in 4 wind turbine farms  

International Nuclear Information System (INIS)

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

304

Friction drive 2 MW wind turbine  

Energy Technology Data Exchange (ETDEWEB)

Details of a friction drive 2 MW wind turbine were presented. The friction drive (FD) concept was comprised of a 3-blade horizontal axis with variable speed operation and no gearbox. The system used multiple small generators with independent load paths in order to provide the potential for higher-rated powers than conventional wind turbines. The FD system was designed for use with lighter nacelle weights in turbines rated at over 4 MW. The FD 65 kW was designed to have a measured friction drive efficiency ranging between 95 to 98 per cent. The electrical generators were synchronized, and a slipping mechanism was used to protect generators at high wind gusts. The protection mechanism only allowed the pre-set torque to be transmitted to power generation components. A slipping device was used when the control system was not able to react quickly enough to sudden or localized wind gusts. Results of simulation studies showed that the system is capable of compensating for extreme wind gusts. Shop tire testing results also showed that the tire materials used in the FD were scalable to 2 MW range with an estimated tire life of between 3 to 5 years. Specifications and wind curves were also included. tabs., figs.

Nayef, N. [CWind Inc., Owen Sound, ON (Canada)

2008-07-01

305

Built-Environment Wind Turbine Roadmap  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-11-01

306

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

International Nuclear Information System (INIS)

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

307

Control, stability analysis and grid integration of wind turbines.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Wang, Chen

2008-01-01

308

Learning in wind turbine development  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 result of the development of wind energy in each country is very different. In the year 2000, Denmark had a flou...

Kamp, Linda Manon

2002-01-01

309

Wind Turbines on CO2 Neutral Luminaries in Urban Areas  

DEFF Research Database (Denmark)

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

310

An experimental investigation of wind turbine aerodynamic interaction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Wind turbine installed capacity in the United States has seen an exponential growth over the last decade and mostly coming in the form of large wind farm installations. The wind farms themselves too have been increasing in size, incorporating more wind turbines in larger areas than ever before. ^ Wind turbines have become a viable component in the overall energy makeup of the United States due to improved economics where energy prices have risen and production costs dropped. For a fixed co...

Ennis, Brandon Lee

2013-01-01

311

Control Logic Algorithm for Medium Scale Wind Turbines  

Directory of Open Access Journals (Sweden)

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

Osama Abdel Hakeem Abdel Sattar

2012-01-01

312

Large wind turbine development in Europe  

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-12-31

313

Fatigue Life of Wind Turbine Blades  

DEFF Research Database (Denmark)

The present paper analyses the possibility of reducing the expected damage accumulation during tower passage by modifying the wind turbine tower design from a traditional mono-tower to a tripod. Due to a narrow stagnation zone the stress reversals and hence the damage accumulation in the blades is substantial smaller in the tripod tower design compared to the mono-tower.

Thoft-Christensen, Palle

2010-01-01

314

Wind Turbine Tribology Seminar - A Recap  

Energy Technology Data Exchange (ETDEWEB)

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

315

Certification and type approval of wind turbines  

International Nuclear Information System (INIS)

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

316

Leasing wind turbines (and its alternatives)  

International Nuclear Information System (INIS)

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

317

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

DEFF Research Database (Denmark)

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

Hansen, Anca Daniela; Cutululis, Nicolaos Antonio

2010-01-01

318

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-01-15

319

Development of the Risoe wind turbine aerofoils  

Energy Technology Data Exchange (ETDEWEB)

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

Fuglsang, P.; Bak, C. [Risoe National Lab., Roskilde (Denmark). Wind Energy Dept.

2004-07-01

320

Detection of Wind Turbine Power Performance Abnormalities Using Eigenvalue Analysis  

DEFF Research Database (Denmark)

Condition monitoring of wind turbines is a field of continu- ous research and development as new turbine configurations enter into the market and new failure modes appear. Systems utilising well established techniques from the energy and in- dustry sector, such as vibration analysis, are commercially available and functioning successfully in fixed speed and vari- able speed turbines. Power performance analysis is a method specifically applicable to wind turbines for the detection of power generation changes due to external factors, such as ic- ing, internal factors, such as controller malfunction, or delib- erate actions, such as power de-rating. In this paper, power performance analysis is performed by sliding a time-power window and calculating the two eigenvalues corresponding to the two dimensional wind speed - power generation dis- tribution. The power is classified into five bins in order to achieve better resolution and thus identify the most proba- ble root cause of the power deviation. An important aspect of the proposed technique is its independence of the power curve provided by the turbine manufacturer. It is shown that by detecting any changes of the two eigenvalues trends in the five power bins, power generation anomalies are consistently identified

Skrimpas, Georgios Alexandros; Sweeney, Christian Walsted

2014-01-01

 
 
 
 
321

Power Performance Test Report for the SWIFT Wind Turbine  

Energy Technology Data Exchange (ETDEWEB)

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

Mendoza, I.; Hur, J.

2012-12-01

322

Orthogonal Bases used for Feed Forward Control of Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In optimizing wind turbines it can be of a large help to use information of wind speeds at upwind turbine for the control of downwind turbines, it is, however, problematic to use these measurements directly since they are highly in?uenced by turbulence behind the wind turbine rotor plane. In this paper an orthogonal basis is use to extract the general trends in the wind signal, which are forward to the down wind turbines. This concept controller is designed and simulated on a generic 4.8 MW...

Odgaard, Peter Fogh; Stoustrup, Jakob

2011-01-01

323

Optimization and Reliability Problems in Structural Design of Wind Turbines  

DEFF Research Database (Denmark)

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

SØrensen, John Dalsgaard

2007-01-01

324

Numerical study of turbulent flow around a wind turbine nacelle  

Science.gov (United States)

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

Masson, Christian; Smaïli, Arezki

2006-05-01

325

Wind Turbine Generator System Acoustic Noise Test Report for the ARE 442 Wind Turbine  

Energy Technology Data Exchange (ETDEWEB)

This test was conducted on the ARE 442 as part of the U.S. Department of Energy's (DOE's) Independent Testing project. This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. In total, five turbines are being tested at the National Wind Technology Center (NWTC) as a part of this project. Acoustic noise testing is one of up to five tests that may be performed on the turbines, including duration, safety and function, power performance, and power quality tests. The acoustic noise test was conducted to the IEC 61400-11 Edition 2.1.

Huskey, A.; van Dam, J.

2010-11-01

326

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

DEFF Research Database (Denmark)

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

Diaz-Guerra, Lluis; Adegas, Fabiano Daher

2012-01-01

327

Design and wind tunnel experimentation of a variable blade drag type vertical axis wind turbine  

Science.gov (United States)

The primary purpose of this research effort is to propose a novel efficiency boosting design feature in a drag type vertical axis wind turbine (VAWT), explore practicality through design and fabrication, and test the viability of the design through wind tunnel experiments. Using adaptive control surface design and an improved blade shape can be very useful in harnessing the wind's energy in low wind speed areas. The new design is based on a series of smaller blade elements to make any shape, which changes to reduce a negative resistance as it rotates and thus maximizing the useful torque. As such, these blades were designed into a modified Savonius wind turbine with the goal of improving upon the power coefficient produced by a more conventional design. The experiment yielded some positive observations with regard to starting characteristics. Torque and angular velocity data was recorded for both the conventional configuration and the newly built configuration and the torque and power coefficient results were compared.

Mays, Samuel; Bahr, Behnam

2012-04-01

328

Generators of Modern Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, various types of wind generator configurations, including power electronic grid interfaces, drive trains, are described The performance in power systems is briefed. Then the optimization of generator system is presented. Some investigation results are presented and discussed.

Chen, Zhe

2008-01-01

329

Design optimization of a cost-effective micro wind turbine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this paper is to investigate the performance of a specially designed micro wind turbine for urban environment where the wind speed is usually low. Differing from the traditional wind turbine that can be connected directly to the grid, the micro wind turbine is linked to a small generator and mainly used for local applications. The advantage of the micro wind turbine is that, apart from its low cost, it can be propelled by a wind speed as low as 2 m/s. In this paper, the performance...

Leung, D. Y. C.; Deng, Y.; Leung, M. K. H.

2010-01-01

330

Minimum Thrust Load Control for Floating Wind Turbine  

DEFF Research Database (Denmark)

— Offshore wind energy capitalizes on the higher and less turbulent wind at sea. Shallow water sites are pro?table for deployment of monopile wind turbines at water depths of up to 30 meters. Beyond 30 meters, the wind is even stronger and less turbulent. At these depths, ?oating wind turbines become pro?table, capable of accessing unexploited wind resources while reaching regions of new consumers. However, ?oating wind turbines are subject to reduced structural stiffness which results in instabilities when standard wind turbine control systems are applied. Based on optimal control, this paper presents a new minimum thrust control strategy capable of stabilizing a ?oating wind turbine. The new control strategy explores the freedom of variable generator speed above rated wind speed. A comparison to the traditional constant speed strategy, shows improvements in structural fore-aft oscillations and power stability when using the new control strategy.

Christiansen, SØren; Bak, Thomas

2012-01-01

331

Database on wind characteristics - Analyses of wind turbine design loads  

Energy Technology Data Exchange (ETDEWEB)

The main objective of IEA R and D Wind Annex XVII - Database on Wind Characteristics - has been to provide wind energy planners, designers and researchers, as well as the international wind engineering community in general, with a source of actual wind field data (time series and resource data) observed in a wide range of different wind climates and terrain types. Connected to an extension of the initial Annex period, the scope for the continuation was widened to include also support to the international wind turbine standardisation efforts.. The project partners are Sweden, Norway, U.S.A., The Netherlands and Denmark, with Denmark as the Operating Agent. The reporting of the continuation of Annex XVII falls in two separate parts. Part one accounts in details for the available data in the established database bank, and part two describes various data analyses performed with the overall purpose of improving the design load cases with relevance for to wind turbine structures. The present report constitutes the second part of the Annex XVII reporting. Both fatigue and extreme load aspects are dealt with, however, with the main emphasis on the latter. The work has been supported by The Ministry of Environment and Energy, Danish Energy Agency, The Netherlands Agency for Energy and the Environment (NOVEM), The Norwegian Water Resources and Energy Administration (NVE), The Swedish National Energy Administration (STEM) and The Government of the United States of America. (au)

Larsen, G.C.; Hansen, K.S.

2004-06-01

332

A New Structure Based on Cascaded Multilevel Converter for Variable Speed Wind Turbine  

DEFF Research Database (Denmark)

An alternative structure for variable speed wind turbine, using multiple permanent magnet synchronous generators (PMSGs) drive-train configuration and cascaded multilevel converter is proposed in this paper. This study presents a power electronic solution for the wind turbine. A transformer-less cascaded multilevel converter interface based on PMSGs is developed to synthesize a desired high ac sinusoidal output voltage. The benefits of high power and high ac voltage make this structure possible to be applied in the wind power generation. In addition, the bulky transformer could be omitted. A simulation model of 10 MW variable speed wind turbine based on PMSGs developed in PSCAD/EMTDC is presented. The dynamic performance of grid-connected wind turbine is analyzed. Simulation results shows that the proposed structure may be attractive in wind power generation.

Deng, Fujin; Chen, Zhe

2010-01-01

333

The sound of wind turbines keeps one busy  

International Nuclear Information System (INIS)

A few reactions are given to the thesis 'The sounds of high winds. The effect of atmospheric stability on wind turbine sound and microphone noise' on the availability of wind at night and related production of noise

334

A new generation of wind turbines; Une nouvelle generation d'eoliennes  

Energy Technology Data Exchange (ETDEWEB)

Although homeowners have expressed a desire to use wind energy to supply their electricity needs, many technical barriers have stood in the way of installing wind turbines in urban settings. This was due in part to three-bladed vertical axis turbines, high technical costs, limited performances in urban settings and questionable aesthetics. Tesnic has considered these issues and proposed a completely different turbine that uses a different method for extracting energy from the wind. The first approved 3.6 kW model should appear by the end of 2009. This new turbine is based on the same principal of the steam turbine patented in 1913 by Nikola Tesla. Instead of having blades, the Tesla turbine used closely spaced parallel disks and was recognized as being very robust with a high efficiency rating. Tesnic's new wind powered turbine is a vertical axis turbine with a series of valves that directs the wind on a rotor assembly of disk space. A series of blades on its circumference redirects the wind through the assembly of discs and accelerates the rotation of the rotor. The turbine extracts the wind energy in several ways, including conventional drag and lift, adherence and the vortex effect. This gives a 50 per cent added value of efficiency compared to other wind powered turbines. The global market for small wind powered energy is in full expansion. It has been projected that small turbines with 1 kW capacity will be abundant by 2020. It was noted that for household wind powered energy, the market must consider issues of cost, low maintenance, noise pollution, visual aesthetics, durability and safety. Wind energy can also be used in several industries, including plastics, composites, light metals, textiles and electronics. 2 figs.

Nica, H. [Tesnic, Laval, PQ (Canada)

2008-06-15

335

Grid integration impacts on wind turbine design and development  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Hansen, Anca Daniela; Cutululis, Nicolaos Antonio; Sørensen, Poul Ejnar; Iov, F.

2009-01-01

336

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

Science.gov (United States)

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

337

Multiple turbine wind power transfer system loss and efficiency analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A gearless hydraulic wind energy transfer system utilizes the hydraulic power transmission principles to integrate the energy of multiple wind turbines in a central power generation location. The gearless wind power transfer technology may replace the current energy harvesting system to reduce the cost of operation and increase the reliability of wind power generation. It also allows for the integration of multiple wind turbines to one central generation unit, unlike the traditional wind powe...

Pusha, Ayana T.

2013-01-01

338

Simulation and experiment of a fuzzy logic based MPPT controller for a small wind turbine system  

Science.gov (United States)

This paper describes the development of a fuzzy logic based maximum power point tracking (MPPT) strategy for a variable speed wind turbine system (VSWT). For this scope, a fuzzy logic controller (FLC) was described, simulated and tested on a real time "hardware in the loop" wind turbine emulator. Simulation and experimental results show that the controller is able to track the maximum power point for various wind conditions and validate the proposed control strategy.

Petrila, Diana; Muntean, Nicolae

2012-09-01

339

Modeling and Operational Testing of an Isolated Variable Speed PMSG Wind Turbine with Battery Energy Storage  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents the modeling and operational testing of an isolated permanent magnet synchronous generator (PMSG), driven by a small wind turbine with a battery energy storage system during wind speed and load variations. The whole system is initially modeled, including the PMSG, the boost converter and the storage system. The required power for the connected loads can be effectively delivered and supplied by the proposed wind turbine and energy storage systems, subject to an appropri...

Barote, L.; Marinescu, C.

2012-01-01

340

Braking System for Wind Turbines  

Science.gov (United States)

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

 
 
 
 
341

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

Science.gov (United States)

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

342

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

Science.gov (United States)

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.

343

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

Energy Technology Data Exchange (ETDEWEB)

Deep C Wind, a consortium headed by the University of Maine will test the first U.S. offshore wind platforms in 2012. In advance of final siting and permitting of the test turbines off Monhegan Island, residents of the island off Maine require reassurance that the noise levels from the test turbines will not disturb them. Pacific Northwest National Laboratory, at the request of the University of Maine, and with the support of the U.S. Department of Energy Wind Program, modeled the acoustic output of the planned test turbines.

Aker, Pamela M.; Jones, Anthony M.; Copping, Andrea E.

2010-11-23

344

Control of large wind turbine generators connected to utility networks  

Science.gov (United States)

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

345

Wind tunnel tests of a free yawing downwind wind turbine  

DEFF Research Database (Denmark)

During February and April 2012 a series of wind tunnel tests were performed at the TU Delft Open Jet Facility (OJF) with a three bladed downwind wind turbine and a rotor radius of 0.8 meters. The setup includes an off the shelf three bladed hub, nacelle and generator on which relatively flexible blades are mounted. The tower support structure has free yawing capabilities provided at the tower base. A short overview on the technical details of the experiment is provided as well as a brief summary of the design process. The discussed test cases show that the turbine is stable while operating in free yawing conditions. Further, the effect of the tower shadow passage on the blade flapwise strain measurement is evaluated. Finally, data from the experiment is compared with preliminary simulations using DTU Wind Energy's aeroelastic simulation program HAWC2.

Verelst, David Robert; Larsen, Torben J.

346

Transient control of grid-connected converters for wind turbines to fulfill emerging grid codes  

Energy Technology Data Exchange (ETDEWEB)

This paper studies the controllability of grid-connected converters for wind turbines during symmetrical grid faults. Voltage phase jump often occurs at transient faults. If the phase-locked loop (PLL) fails to capture the voltage phase immediately, wind turbines can not control active and reactive power quickly, and even be damaged, especially for DFIG-based wind turbines. This paper proposes a dynamic reference frame, which helps the controller of the grid-connected converter be oriented to the grid voltage vector immediately. Taking the full-capacity wind turbine as an example, feasibility of the dynamic reference frame is analyzed in detail. Simulation results show that wind turbines can output controllable power quickly with the dynamic reference frame employed, which fulfills emerging grid codes. (orig.)

Tong, Dan; Yuan, Xiaoming; Hu, Jiabing [Huazhong Univ. of Science and Technology, Wuhan (China). State Key Laboratory of Advanced Electromagnetic Engineering and Technology

2012-07-01

347

Calculation of transient potential rise on the wind turbine struck by lightning.  

Science.gov (United States)

A circuit model is proposed in this paper for calculating the transient potential rise on the wind turbine struck by lightning. The model integrates the blade, sliding contact site, and tower and grounding system of the wind turbine into an equivalent circuit. The lightning current path from the attachment point to the ground can be fully described by the equivalent circuit. The transient potential responses are obtained in the different positions on the wind turbine by solving the circuit equations. In order to check the validity of the model, the laboratory measurement is made with a reduced-scale wind turbine. The measured potential waveform is compared with the calculated one and a better agreement is shown between them. The practical applicability of the model is also examined by a numerical example of a 2?MW Chinese-built wind turbine. PMID:25254231

Xiaoqing, Zhang

2014-01-01

348

Calculation of Transient Potential Rise on the Wind Turbine Struck by Lightning  

Science.gov (United States)

A circuit model is proposed in this paper for calculating the transient potential rise on the wind turbine struck by lightning. The model integrates the blade, sliding contact site, and tower and grounding system of the wind turbine into an equivalent circuit. The lightning current path from the attachment point to the ground can be fully described by the equivalent circuit. The transient potential responses are obtained in the different positions on the wind turbine by solving the circuit equations. In order to check the validity of the model, the laboratory measurement is made with a reduced-scale wind turbine. The measured potential waveform is compared with the calculated one and a better agreement is shown between them. The practical applicability of the model is also examined by a numerical example of a 2?MW Chinese-built wind turbine. PMID:25254231

Xiaoqing, Zhang

2014-01-01

349

Fault Detection and Isolation and Fault Tolerant Control of Wind Turbines Using Set-Valued Observers  

DEFF Research Database (Denmark)

Research on wind turbine Operations & Maintenance (O&M) procedures is critical to the expansion of Wind Energy Conversion systems (WEC). In order to reduce O&M costs and increase the lifespan of the turbine, we study the application of Set-Valued Observers (SVO) to the problem of Fault Detection and Isolation (FDI) and Fault Tolerant Control (FTC) of wind turbines, by taking advantage of the recent advances in SVO theory for model invalidation. A simple wind turbine model is presented along with possible faulty scenarios. The FDI algorithm is built on top of the described model, taking into account process disturbances, uncertainty and sensor noise. The FTC strategy takes advantage of the proposed FDI algorithm, enabling the controller reconfiguration shortly after fault events. Additionally, a robust controller is designed so as to increase the wind turbine's performance during low severity faults. Finally, the FDI algorithm is assessed within a publicly available benchmark model, using Monte-Carlo simulation runs.

Casau, Pedro; Rosa, Paulo Andre Nobre

2012-01-01

350

Wind turbines in the Netherlands?  

International Nuclear Information System (INIS)

The Dutch government plans to have 3000 MW wind power installed in the Netherlands in the year 2020. It is argued that the electricity production is relatively low, the costs for construction and maintenance are high and the use of space considerable

351

Wind turbine reliability database update.  

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-03-01

352

Wind turbine control and model predictive control for uncertain systems  

DEFF Research Database (Denmark)

This thesis presents both an applied study and a theoretical study within the field of control theory. Control theory is an interdisciplinary branch between mathematics and engineering dealing with the manipulation of systems to produce a desired output. The applied study deals with wind turbine control. Wind turbines are controlled to optimize energy extraction from the wind. This must be done while respecting physical restrictions and ensuring that loads on the wind turbine structure does not seriously reduce the lifetime of components. This poses a trade-off in the design and the wind turbine problem is hence a complex multivariable problem. In this thesis the main focus is on design of controllers which optimally attenuates the impact of the variability in the wind. The angles of the wind turbine blades have been used as the primary control variable to achieve this goal. Strategies have been studied in which the blades are controlled collectively and individually. The wind has both temporal and spatial variations with a stochastic nature. Furthermore, the wind has deterministic (or slowly varying) trends. Large parts of the thesis hence deals with developing wind models which can be used as disturbance models for controller design. The theoretical study deals with Model Predictive Control (MPC). MPC is an optimal control method which is characterized by the use of a receding prediction horizon. MPC has risen in popularity due to its inherent ability to systematically account for time-domain constraints on signals. During the last decades several theoretical advances have been made, so that it can handle a wide variety of system structures. In this thesis, the focus is on handling uncertain linear system description. To this end the so-called Youla parameterizations have been used. Two methods are proposed: The first method exploits the modularity of the parameterizations so that the uncertainty can be identified and the MPC controller can be reconfigured in a modular setting. The second method is a robust MPCmethod in which the Youla parameters are used as an integral part of the online optimization. In this way stability can be guaranteed given an assumed bound on the uncertainty. The contributions of the thesis have been documented in a series of scientific papers. The papers form the main part of this thesis.

Thomsen, Sven Creutz

2010-01-01

353

Highway damage due to movement of wind turbine components  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes a methodology for assessing the damage imposed by the movement of wind turbine components on Texas’s highway infrastructure. The pavement damage associated with traffic resulting from site preparation was omitted from the scope of this study because reliable data characterizing the construction traffic were not available. The damage to the pavement structure was estimated using three primary distresses: rutting, longitudinal, and alligator cracking. In addition, the impa...

Banerjee, A.; Prozzi, J. A.; Prozzi, Jolanda

2012-01-01

354

Automated wind turbine pitch fault prognosis using ANFIS.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Many current wind turbine (WT) studies focus on improving their reliability and reducing the cost of energy, particularly when WTs are operated offshore. WT Supervisory Control and Data Acquisition (SCADA) systems contain alarms and signals that provide significant important information. A possible WT fault can be detected through a rigorous analysis of the SCADA data. This paper proposes a new method for analysing WT SCADA data by using Adaptive Neuro-Fuzzy Inference System (ANFIS) with the ...

Chen, Bindi; Matthews, P. C.; Tavner, P. J.

2013-01-01

355

Structural Robustness Evaluation of Offshore Wind Turbines  

DEFF Research Database (Denmark)

Wind turbines are complex structures that should deal with adverse weather conditions, are exposed to impacts or ship collisions and, due to the strategic roles in the energetic supplying, can be the goal of military or malevolent attacks. Even if a structure cannot be design to resist any unforeseeable critical event or arbitrarily high accidental action, this kind of systems should be able to maintain integrity and a certain level of functionality also under accidental circumstances, which are not contemplated or cannot be considered in the usual design verification. According to a performance-based design view, the entity of actions to be resisted and the services levels to be maintained are the design objectives, which should be defined by the stakeholders and by the designer in respect of the regulation in force. For what said above, the structural integrity of wind turbines is a central issue in the framework of a safe design: it depends on different factors, like exposure, vulnerability and robustness.Particularly, the requirement of structural vulnerability and robustness are discussed in this paper and a numerical application is presented, in order to evaluate the effects of a ship collision on the structural system of an offshore wind turbine. The investigation resorts nonlinear dynamic analyses performed on the finite element model of the turbine and considers three different scenarios for the ship collision. The review of the investigation results allows for an evaluation of the turbine structural integrity after the impact and permits to identify some characteristics of the system, which are intrinsic to the chosen organization of the elements within the structure.

Giuliani, Luisa

2010-01-01

356

Mapping of grid faults and grid codes[Wind turbines  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to investigate into the consequences of the new grid connection requirements for the fatigue and extreme loads of wind turbines. The goal is also to clarify and define possible new directions in the certification process of power plant wind turbines, namely wind turbines, which participate actively in the stabilisation of power systems. Practical experience shows that there is a need for such investigations. The grid connection requirements for wind turbines have increased significantly during the last 5-10 years. Especially the requirements for wind turbines to stay connected to the grid during and after voltage sags, imply potential challenges in the design of wind turbines. These requirements pose challenges for the design of both the electrical system and the mechanical structure of wind turbines. An overview over the frequency of grid faults and the grid connection requirements in different relevant countries is done in this report. The most relevant study cases for the quantification of the loads' impact on the wind turbines' lifetime are defined. The goal of this report is to present a mapping of different grid fault types and their frequency in different countries. The report provides also a detailed overview of the Low Voltage Ride-Through Capabilities for wind turbines in different relevant countries. The most relevant study cases for the quantification of the loads' impact on the wind turbines' lifetime are defined. (au)

Iov, F. [Aalborg Univ., Inst. of Energy Technology (Denmark); Hansen, Anca D.; Soerensen, Poul; Cutululis, N.A. [Risoe National Lab. - DTU, Wind Enegy Dept., Roskilde (Denmark)

2007-06-15

357

Large mills attract the wind. Part 2. Noise pollution of wind turbines at night  

International Nuclear Information System (INIS)

Noise measurements were carried out for the wind turbine array (17 wind turbines) in Bellingwedde, Netherlands. Residents complained about shadows (flickering of light) in the morning hours and noise at night

358

Aeroelastic optimization of MW wind turbines  

Energy Technology Data Exchange (ETDEWEB)

This report contains the results from the Energy Development and Demonstration Project ''Aeroelastic Optimization of MW wind turbine'' (AeroOpt). The project has had the following five Work Packages: 1. Geometric non-linear, anisotropic beam element for HAWC2. 2. Closed-loop eigenvalue analysis of controlled wind turbines. 3. Resonant wave excitation of lateral tower bending modes. 4. Development of next generation aerodynamic design tools. 5. Advanced design and verification of airfoils. The purposes of these Work Packages are briefly described in the Preface and a summary of the results are given in Section 2. Thereafter, the results from each Work Package are described in eight subsequent chapters. (Author)

Hartvig Hansen, M.; Zahle, F.

2011-12-15

359

Offshore Wind Turbine Design : Addressing Uncertainty Drivers  

DEFF Research Database (Denmark)

Current offshore wind turbine design methods have matured to a 1st generation state, manifested in the draft of a possible standard, IEC 61400-3 (2005). It is now time to investigate the possibilities of improving existing methods. To do so in an efficient manner a clear identification of the most important uncertainty drivers specific for offshore wind turbine design loads is required. Describing the initial efforts in a Danish research project, the paper points to focal points for research and development. These are mainly: soil-structure interaction, improved modelling of wave loads from deep to shallow waters, integrated re-sponse modelling, wake effects, response extrapola-tion and clarification of the relevance of deterministic load cases in the operational regime.

Frandsen, Sten; Hansen, Erik Asp

2006-01-01

360

Effect of Rotor Current Control for Wound Rotor Induction Generator on the Wind Turbine Performance  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the effect of rotor current control of wound rotor induction generator driven by wind turbine during different operation modes when varying the rotor resistance. The studied modes are wind speed variation, starting especially at high wind speed. Moreover, the effect of the proposed control on short circuit and critical fault clearing time is investigated.

Mahmoud Rabie Barakat

2012-03-01

 
 
 
 
361

Effect of Rotor Current Control for Wound Rotor Induction Generator on the Wind Turbine Performance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents the effect of rotor current control of wound rotor induction generator driven by wind turbine during different operation modes when varying the rotor resistance. The studied modes are wind speed variation, starting especially at high wind speed. Moreover, the effect of the proposed control on short circuit and critical fault clearing time is investigated.

Mahmoud Rabie Barakat

2012-01-01

362

Wear Analysis of Wind Turbine Gearbox Bearings  

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-04-01

363

Modelling and prevention of ice accretion on wind turbines  

Energy Technology Data Exchange (ETDEWEB)

A numerical model that simulates ice accretion amounts and ice shapes on wind turbine blades is presented. The model simulates both rime icing due to fog droplets and glaze icing due to precipitation at all angles of droplet attack experienced by wind turbine blades. Icing can be simulated by the model also when the blade is heated. The sensitivity of ice accretions to meteorological variables is studied and predictions of the model are compared to data from icing wind tunnel experiments and from a field study of natural wind turbine icing. Applications of the model in the design of blade heating elements for anti-icing of wind turbines are described. (author)

Makkonen, L. [Technical Research Centre of Finland, Espoo (Finland). VTT Building and Transport; Laakso, T.; Marjaniemi, M. [Technical Research Centre of Finland, Espoo (Finland). VTT Energy; Finstad, K.J.

2001-07-01

364

Composite Materials for Wind Power Turbine Blades  

Science.gov (United States)

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

365

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-09-01

366

Active system monitoring applied on wind turbines  

DEFF Research Database (Denmark)

A concept for active system monitoring (ASM) applied on wind turbines is presented in this paper. The concept is based on an injection of a small periodic auxiliary signal in the system. An investigation of the signature from the auxiliary input in residual (error) signals can then be applied for an online monitoring of central parameters/elements of the system. Statistical tests are applied on the residual signals for obtaining a correct monitoring.

Niemann, Hans Henrik; Poulsen, Niels KjØlstad

2009-01-01

367

Wind turbine SCADA alarm pattern recognition.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Current wind turbine (WT) studies focus on improving their reliability and reducing the cost of energy, particularly when they are operated offshore. WT Supervisory Control and Data Acquisition (SCADA) systems contain alarm signals providing significant important information. Pattern recognition embodies a set of promising techniques for intelligently processing WT SCADA alarms. This paper presents the feasibility study of SCADA alarm processing and diagnosis method using an artificial neural...

Bindi, Chen; Qiu, Y. N.; Feng, Y.; Tavner, P. J.; Song, W. W.

2011-01-01

368

12MW: final report; Wind turbines  

Energy Technology Data Exchange (ETDEWEB)

'12MW: final report' is for the project with the full title '12 MW wind turbines: the scientific basis for their operation at 70 to 270 m height offshore' that had the goal to experimentally investigate the wind and turbulence characteristics between 70 and 270 m above sea level and thereby establish the scientific basis relevant for the next generation of huge 12 MW wind turbines operating offshore. The project started 1st October 2005 and ended 31st March 2009. Firstly was conducted a 6-month experiment at the Horns Rev offshore wind farm deploying a lidar and a sodar on the transformer platform. The observed data were successfully compared to offshore mast data and the wind profile was extended 100 m above previous levels observed in this offshore environment. The wind and turbulence was observed up to 160m above mean sea level. A new normalization was introduced to group the wind profiles into stability groups with variable roughness. Secondly two experiments were conducted at Hoevsoere at the North Sea coast in Jutland. Again the wind profile was extended far beyond previous observed levels, up to 300 m above ground. The analysis showed that the profiles extended far beyond the surface layer and therefore surface layer scale alone could not described the profiles well. In addition the boundary layer height has to be used for the scaling. The boundary layer height was observed by an aerosol lidar at Hoevsoere. The results are published widely, please see the list of publications. (au)

Hasager, C.; Pena, A.; Mikkelsen, T.; Gryning, S.-E.; Courtney, M.; Soerensen, Paul B. (DONG energy)

2009-06-15

369

Shape Optimization of Wind Turbine Blades  

DEFF Research Database (Denmark)

This paper presents a design tool for optimizing wind turbine blades. The design model is based on an aerodynamic/aero-elastic code that includes the structural dynamics of the blades and the Blade Element Momentum (BEM) theory. To model the main aero-elastic behaviour of a real wind turbine, the code employs 11 basic degrees of freedom corresponding to I I elastic structural equations. In the BEM theory, a refined tip loss correction model is used. The objective of the optimization model is to minimize the cost of energy which is calculated from the annual energy production and the cost of the rotor. The design variables used in the current study are the blade shape parameters, including chord, twist and relative thickness. To validate the implementation of the aerodynamic/aero-elastic model, the computed aerodynamic results are compared to experimental data for the experimental rotor used in the European Commision-sponsored project Model Experiments in Controlled Conditions, (MEXICO) and the computed aero-elastic results are examined against the FLEX code for flow post the Tjereborg 2 MW rotor. To illustrate the optimization technique, three wind turbine rotors of different sizes (the MEXICO 25 kW experimental rotor, the Tjareborg 2 MW rotor and the NREL 5 MW virtual rotor) are applied. The results show that the optimization model can reduce the cost of energy of the original rotors, especially for the investigated 2 MW and 5 MW rotors. Copyright (C) 2009 John Wiley & Sons, Ltd.

Wang, Xudong; Shen, Wen Zhong

2009-01-01

370

Atmospheric icing on large wind turbine blades  

Energy Technology Data Exchange (ETDEWEB)

A numerical study of atmospheric ice accretion on a large horizontal axis 'NREL 5 MW' wind turbine blade has been carried out using the computational fluid dynamics based technique. Numerical analyses were carried out at five different sections along the wind turbine blade for both rime and glaze ice conditions. Based upon the flow field calculation and the droplet collision efficiency, the rate and shape of accreted ice was simulated at different atmospheric temperatures. Results indicate that the icing is less severe near the blade root sections, where the blade profiles are larger and thicker, both in terms of local ice mass and accreted ice thickness. Change in accreted ice growth with the atmospheric temperature is significant along the blade sections from centre to tip. The research work also highlighted that the ice accretion on wind turbine blades can also be controlled by optimizing its geometric design features instead of only using the energy consuming anti icing and de-icing systems.

Virk, Muhammad S.; Nicklasson, Per J. [Department of Technology, Barvik University College, 8505 Narvik (Norway); Homola, Matthew C. [Nordkraft Produksjon, Narvik (Norway)

2012-07-01

371

Atmospheric icing on large wind turbine blades  

Directory of Open Access Journals (Sweden)

Full Text Available A numerical study of atmospheric ice accretion on a large horizontal axis ‘NREL 5 MW’ wind turbine blade has been carried out using the computational fluid dynamics based technique. Numerical analyses were carried out at five different sections along the wind turbine blade for both rime and glaze ice conditions. Based upon the flow field calculation and the droplet collision efficiency, the rate and shape of accreted ice was simulated at different atmospheric temperatures. Results indicate that the icing is less severe near the blade root sections, where the blade profiles are larger and thicker, both in terms of local ice mass and accreted ice thickness. Change in accreted ice growth with the atmospheric temperature is significant along the blade sections from centre to tip. The research work also highlighted that the ice accretion on wind turbine blades can also be controlled by optimizing its geometric design features instead of only using the energy consuming anti icing and de-icing systems.

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

2012-01-01

372

Wind turbine blade tip comparison using CFD  

International Nuclear Information System (INIS)

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

373

WEST-3 wind turbine simulator development  

Science.gov (United States)

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

374

Actuator Control of Edgewise Vibrations in Wind Turbine Blades  

DEFF Research Database (Denmark)

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

Staino, A.; Basu, B.

2012-01-01

375

Low frequency sound from wind turbine arrays  

International Nuclear Information System (INIS)

Due to the effects of tower wakes and atmospheric turbulence, wind turbines emit sounds at low frequencies characterized by the turbine blade passage frequency and its harmonics. These frequencies range from the sub-audible tones of a few hertz up to frequencies in the lower audible range of 50 to 100 Hz. The results of tests on a small controlled array of turbines at the U.S. Windpower Windplant in Altamont Pass, California, indicate that the low frequency sound propagates according to the well established physical principle of spherical spreading. The effect of operating multiple turbines can be accurately modeled by considering each turbine to be a randomly phased acoustic point source. In order to characterize the low frequency sound, the AWEA Standard, Low-Frequency, C-Weighted metric is recommended for both rms and impulse-hold transient signal processing. To assess the effects of this low frequency sound on community receptors an appropriate criterion based on previous results and a corresponding simplified methodology are developed. (Author)

376

Power Quality Enhancement in Wind Turbine Fed FSIG under asymmetric faults using SVPWM control  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the mitigation of faults in wind turbine connected fixed speed induction generator using distribution static compensator because of its excellent performance of fault mitigation. The D current controlled voltage source converter used for reactive power compensation when connected to the power system. The control system of the proposed d proposed wind turbine fed fixed speed induction generator is evaluated and simulated using SIMULINK/MATLAB environment with and without D-statcomunder asymmetric faults

P. Karthigeyan

2014-02-01

377

Generic aerodynamic model for simulation of variable speed wind turbines  

Energy Technology Data Exchange (ETDEWEB)

There is an increased international interest in electrical simulation models of wind turbines for stability analysis and interconnection studies. So-called ''generic'' models, with a model structure that is publicly available, have been required in the USA by many utilities. A working group of the Western Electricity Coordinating Council (WECC) and IEEE has developed models for different types of generators, among others for wind turbines using doubly fed induction generators (DFIG) and full size converters (FSC). Those models were so far mainly used in the USA, and the models were able to represent wind turbines with respect to common US grid code requirements. Due to an increased international interest in generic models, there is a need for updating existing models in order to improve the accuracy of the models since validation requirements in many countries now require a comparison with measurements (and not to more detailed simulation models only). It can be shown that the proposed model allows for an improved representation of the aerodynamic effects during grid faults compared to existing model approaches based on cp {lambda}-tables while still requiring far less parameters. The results of simulations using the proposed generator model are compared to measurements during voltage dips of a 2MW and 6MW wind turbine. The new generic aerodynamic model will be proposed as extension for the WECC/IEEE aerodynamic models as well as basis for the draft of the IEC TC88 working group 27 (61400-27) on modelling and model validation. (orig.)

Fortmann, Jens [REpower Systems AG, Osterroenfeld (Germany)

2010-07-01

378

High Voltage Power Converter for Large Wind Turbine  

DEFF Research Database (Denmark)

The increasing penetration of the wind energy has resulted in newly planned installations of offshore wind turbines. In order to minimize installation, material and transportation costs of the offshore wind power plants, large multi-MW wind turbine systems are being preferably employed and developed, which allow high power generation of each single unit. Nevertheless, further increase in the power ratings of the newly emerging turbines becomes a major concern related to the operating voltage level. In order to accommodate larger powers, presently employed low voltage (690 V) systems already require multi-parallel converter and filter modules, which increase the overall complexity. In this thesis, a concept for the medium voltage wind turbine is examined and evaluated, where voltage increase is dictated by the removal of the step-up transformer. As a result, an entire wind turbine electrical system operates at 20 kV level - identical as for the collector distribution network. Medium voltage operation allows the converter unit along with the filter to be installed on the base platform inside the tower. In this manner, more space in the nacelle can be flexibly accommodated by the mechanical parts. Due to limited voltage level of the generator insulation system (15 kV) along with the increasing grid integration requirements, special care has been made over the search for optimal full-scale power converter circuitry, which additionally has to compensate voltage differences between the generator-side and a grid-side. Three converter topologies with different conversion philosophies have been introduced (A, B and C), their performance examined and eventually compared with the conventional low voltage system. System A is a back-to-back MMC converter, which is commonly used in HVDC application. System B consists of the generator-side 2-level converter, DC/DC boost unit and a grid-side NPC-3L converter. System C is made of a seriesconnected full-bridge cells on the generator-side, and a grid-side NPC-5L converter. The performance of the proposed topologies is analyzed both under the normal and fault operation. In normal operation, medium and low voltage converter topologies are compared with regard to the efficiency and the required amount of silicon material in the semiconductor switches. In fault operation, maximum temporary ratings of the collector feeder components are compared also for different grounding schemes, which impact is the result of the removed step-up transformer. Finally, the ground fault detection scheme for feeder cable system is proposed - with the usage of current differential relay. Due to lack of the galvanic separation between the wind turbines and the feeder cable sections, careful investigation for the relay selective operation has been made, which distinguishes ground faults located at the wind turbine terminals from faults within the protected cables. The obtained results from the computer simulations in EMTDC/PSCAD software show, that the best performance has been achieved by the transformer-less turbine with a back-to-back modular multilevel converter (MMC) topology, which is single grounded only through its DC link common-mode point. It has also occurred that the results derived from losses and short circuit analyses have become advantageous over the equivalent conventional system consisting of low voltage wind turbines equipped with the step up transformer.

Sztykiel, Michal

2014-01-01

379

Wind turbine improvements by wind-lidar-based preview and control  

DEFF Research Database (Denmark)

Wind turbines equipped with laser prevision hold potential for up to 6+ years lifetime extension. Forward looking wind lidars integrated within operational wind turbines providing feed-forward control can reduce the daily operation loads. The turbine lifetime may in this way be extended by up to 30 percent.

Mikkelsen, Torben

2014-01-01

380

High power horizontal axis wind turbines dynamic behaviour modeling  

International Nuclear Information System (INIS)

Facing to a very competing market, the manufacturers have to propose increasingly reliable and powerful turbines, at lower cost, with greater and greater rotor diameter. In this context, it proves to be crucial to have tools able to quickly calculate the loads, in order to be able to design them correctly. The wind turbines are complex mechanical systems composed of rigid or flexible bodies. The major part of the current codes treat correctly only the part relating to the aerodynamic loads, and lie on assumptions which can be too simplified with regard to the calculation of the dynamic loads, especially when the size of the rotor increases. Consequently, the aim of this work was then to model the wind turbine dynamic behaviour avoiding drastic simplifications, which could affect the precision of the results. To do this, the Kane's formalism was employed, as well as the description of the kinematic chain through a topological tree-like structure, which allows a recursive and purely numerical building of equations of motion, facilitating its algorithmic treatment, without any simplification. The method developed for the most general case makes possible to model any type of wind turbine, thanks to the improvements made to the basic formalism. It takes into account the behaviour of the rigid bodies (nacelle) as well as flexible ones (blades), for which the flexibility was introduced through a modal representation basis. A computer code was written and validated on some simple cases, by comparison with exact analytical solutions. The calculation of the aerodynamic loads was then coupled to model the mechanical behaviour of an wind turbine starting from realistic data. (author)

 
 
 
 
381

Constant Power Control Of 15 DFIG Wind Turbines With Superconducting Magnetic Energy Storage System  

Directory of Open Access Journals (Sweden)

Full Text Available With the increasing penetration of wind power into electric power grids, energy storage devices will be required to dynamically match the intermittency of wind energy. This paper proposes a novel two-layer constant power control scheme for a wind farm equipped with doubly fed induction generator (DFIG wind turbines. Each DFIG wind turbine is equipped with a superconducting magnetic energy storage system (ESS and is controlled by the low-layer wind turbine generator (WTG controllers and coordinated by a high-layer wind farm supervisory controller (WFSC. The WFSC generates the active power references for the low-layer WTG controllers according to the active power demand from or generation commitment to the grid operator; the low-layer WTG controllers then regulate each DFIG wind turbine to generate the desired amount of active power, where the deviations between the available wind energy input and desired active power output are compensated by the ESS. Simulation studies are carried out in MATLAB/SIMULINK on a wind farm equipped with 15 DFIG wind turbines to verify the effectiveness of the proposed control scheme.

V.Krishnamurthy 1 , Ch.Rajesh Kumar

2013-09-01

382

Plasma Aerodynamic Control Effectors for Improved Wind Turbine Performance  

Energy Technology Data Exchange (ETDEWEB)

Orbital Research Inc is developing an innovative Plasma Aerodynamic Control Effectors (PACE) technology for improved performance of wind turbines. The PACE system is aimed towards the design of "smart" rotor blades to enhance energy capture and reduce aerodynamic loading and noise using flow-control. The PACE system will provide ability to change aerodynamic loads and pitch distribution across the wind turbine blade without any moving surfaces. Additional benefits of the PACE system include reduced blade structure weight and complexity that should translate into a substantially reduced initial cost. During the Phase I program, the ORI-UND Team demonstrated (proof-of-concept) performance improvements on select rotor blade designs using PACE concepts. Control of both 2-D and 3-D flows were demonstrated. An analytical study was conducted to estimate control requirements for the PACE system to maintain control during wind gusts. Finally, independent laboratory experiments were conducted to identify promising dielectric materials for the plasma actuator, and to examine environmental effects (water and dust) on the plasma actuator operation. The proposed PACE system will be capable of capturing additional energy, and reducing aerodynamic loading and noise on wind turbines. Supplementary benefits from the PACE system include reduced blade structure weight and complexity that translates into reduced initial capital costs.

Mehul P. Patel; Srikanth Vasudevan; Robert C. Nelson; Thomas C. Corke

2008-08-01

383

Failure Analysis of Wind Turbines by Probability Density Evolution Method  

DEFF Research Database (Denmark)

The aim of this study is to present an efficient and accurate method for estimation of the failure probability of wind turbine structures which work under turbulent wind load. The classical method for this is to fit one of the extreme value probability distribution functions to the extracted maxima of the response of wind turbine. However this approach may contain high amount of uncertainty due to the arbitrariness of the data and the distributions chosen. Therefore less uncertain methods are meaningful in this direction. The most natural approach in this respect is Monte Carlo (MC) simulation. This is not practical due to its excessive computational load. This problem can alternatively be tackled if the evolution of the probability density function (PDF) of the response process can be realized. The evolutionary PDF can then be integrated on the boundaries of the problem. For this reason we propose to use the Probability Density Evolution Method (PDEM). PDEM can alternatively be used to obtain the distribution of the extreme values of the response process by simulation. This approach requires less computational effort than integrating the evolution of the PDF; but may be less accurate. In this paper we present the results of failure probability estimation using PDEM. The results will then be compared to extrapolated values obtained from extreme value distribution fits to the sample response values. The results approve the feasibility of this approach for reliability analysis of wind turbines however they convey the potential for improving accuracy of the method in low probability areas

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

2013-01-01

384

Estimation of turbulence level and scale for wind turbine applications  

Energy Technology Data Exchange (ETDEWEB)

A simplified method is presented for estimating onsite turbulence variance within the wind turbine layer for horizontal wind speed. The method is based principally on estimating the probability distribution of wind speed and assigning a variance to each mean wind speed based on surface roughness estimates. The model is not proposed as an alternative to onsite measurement and analysis, but rather as an adjunct to such a program. A revision of the Kaimal neutral u-component spectrum is suggested to apply to the mix of the stabilities occurring during operational winds. Values of integral length scale calculated from data analysis are shown to contradict the length scale model implicit in turbulence power spectra. Also, these calculated values are shown to be extremely sensitive to the length of the time series and the detrending method used. The analysis and modeling are extended to the rotational frame of reference for a horizontal-axis wind turbine by modeling the ratios of harmonic spike variances (1P, 2P, etc.) in the rotational spectrum to the Eulerian turbulence variance. 15 refs., 11 figs., 3 tabs.

Powell, D.C.

1988-11-01

385

Parametric Studies for Vertical Axis Wind Turbine Simulations  

Science.gov (United States)

Efficiency of the vertical axis wind turbine depends on turbine design. Wind tunnel experiments, usually performed for evaluation of turbine design, are expensive in comparison with CFD simulations. Although purely numeric, CFD models critically depend on a large set of parameters, which varies from mesh size to numerical schemes and models of turbulence. The aim of the presented research is to evaluate the critical ranges of these parameters for a practically applicable turbine design.

Gulbe, Linda; Jekabsons, Normunds; Traskovs, Agris

2011-01-01

386

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

Energy Technology Data Exchange (ETDEWEB)

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