Vertical axis wind turbines (VAWT) have many advantages over traditional Horizontalaxis wind turbines (HAWT).One of the more severe problem of VAWTs are the complicated aerodynamicbehavior inherent in the concept. Incontrast to HAWTs the blades experience varying angle of attack during its orbitalmotion. The unsteady flowleads to unsteady loads, and hence, to increased risk for problems with fatigue.A tool for aerodynamic analysis of vertical axis wind turbines has been developed.The model, a Discrete vortex method, relies on conformal maps to simplify the taskto finding the flowaround cylinders. After the simplified problem has been solved with Kutta condition,using the Fast Fouriertransform, the solution is transformed back to the original geometry yielding the flowabout the turbine.The program can be used for quick predictions of the aerodynamic blade loads fordifferent turbines allowing the method to be validated by comparing the predictionsto experimental data from realvertical axis wind turbines. The agreement with experiment is good.

Wind power is the most mature green energy source in electric power systems and is now a booming worldwide industry. The use of wind power is growing rapidly throughout the world to reduce environmental degradation. Due to global environmental concerns and public awareness, many power utilities around the world are considering wind energy as a substitute for conventional generation. Many governments already have energy plans and policies in place to ensure significantincrease in power generation using wind energy within designated time periods. The wind is variable, site specific and is an intermittent source of energy. It is therefore a complex task to analyze generating system capacity adequacy considering wind energy. The growing application of wind power dictates the need to develop methods to evaluate the system reliability and the capacity value of wind power. Wind is generally considered to be a source of energy, rather than a power source. It is equally important however, to consider the capacity credit of wind power as its penetration increases in electric power systems. It is very important for both electric power utilities and wind power developers to accurately assess wind capacity credit and therefore it is necessary to study and develop different methodologies for performing this task. The research presented in this thesis examines a range of methods used for the evaluation of wind capacity credit using data from four wind sites in Saskatchewan. The techniques, methods and results presented in this thesis should prove to be valuable for system planners assessing generating capacity adequacy evaluation incorporating wind energy.

Thesis (Ph.D.)--University of Texas at Arlington, 2009.

Thesis (doctoral)--Uppsala University, 1990. / Summary in English. Leaf with thesis statement inserted. Includes bibliographical references (p. 292-300).

Thesis--Virginia Polytechnic Institute and State University. / Vita. Abstract. Includes bibliographical references (leaves 116-117). Also available via the Internet.

The generation of electricity using wind turbines is now widespread and commercially viable. There are two aspects of wind energy which are critically important. Firstly, the evaluation of the wind resource, both on nationally and on a local scale. Secondly, the integration of electricity generated by wind turbines into existing electricity grids without reducing the reliability of supply or reducing the overall economic efficiency of the system. This thesis examines both these aspects. Chapters 3 and 4 are concerned with the large scale utilisation of wind energy. Chapter 3 discusses the suitability for wind energy evaluation of the data held by the UK Meteorological office, describes the results of a detailed examination of over 130 station-years of hourly data, and recommends areas of further study as well as a UK standard for site description. Chapter 4 describes a computer model used to examine the effects of integrating wind-generated electricity into the CEGB National Grid and the results obtained with it. The relative importance of dispersal of wind turbines, load and wind forecasting, variation of turbine characteristics and inter-annual variability of wind speed is determined. Chapters 5 and 6 are concerned with a detailed evaluation of thewind energy potential on the Shetland island group. Chapter 5 describes the planning, testing and installation of two hill-top monitoring stations on Shetland and the results found. Chapter 6 describes the development of a computer model of the Shetland Power Station, which is used to examine how the introduction of wind turbines would affect the operation of the power station and the maximum energy penetration possible before power cuts occur. Both chapters conclude with detailed recommendations which will be of worldwide use as the wind energy potential of other diesel-fuelled grids is determined.

The configuration of a wind turbine and its control system dictate the dynamics of the machine. Since the dynamics of each part of the wind turbine affect those of the others, the machine should be considered as an integrated unit. The objective of the research reported here is to lay the foundations for the control aspects of integrated design by determining the dependence of the power controller performance of medium- and largescale, actively regulated, up-wind, horizontal-axis, grid-connected wind turbines on their configuration, that is, the dependence of the magnitude of the loads experienced by the drive train on the machine characteristics. There is a tendency amongst manufacturers to move from conventional, heavy and stiff machines to ones with lighter and more flexible components which makes machines more dynamically active and hence makes the power control task more difficult. Simple thoroughly derived linear and non-linear models of the significant wind turbine dynamics for power control are used to obtain a greater understanding of how machine parameters effect the overall behaviour of the power train. The dependence of the power controller performance of different full-span and tip-regulated machines is discussed. Finally, explanation of the results is illustrated with regard to the design of a 1 MW wind turbine.

China is an energy production and consumption country, wind power is one of the greatest development potential energy.The authors use literature research methodology, case study, comparative study and trend analysis study to analysis current condition of the breeze wind power.China has a long history of wind development, use wind power to generate electric is only developed in recent years, but it is expanding fast. China is a country covering vast territory, and it is rich in wind resources. But some reasons such like natural, economy, environmental etc, limit the wind power development of China.The VAWT is a new kind of wind driven generator, it has many advantages that HAWT doesn’t have. Utilize VAWT to develop breeze wind power generation, will bring wind power into more families.

No description available.

In attempting to control the power output of a wind farm, it is first necessary to smooth the power fluctuations due to wind turbulence. This is accomplished by spatial smoothing, whereby the high frequency power components of a single wind turbine generator (WTG) is reduced by a factor of N-1/2, where N is the number of WTGs in the farm. For this reason the first part of the thesis is concerned with developing a model of smoothing in a wind farm and justifying it mathematically. / After spatial smoothing, the wind farm output still contains low frequency fluctuations. The second part of the thesis makes use of a combination of: (i) pitch angle control of the turbine blades, (ii) power electronic control of the generators, (iii) spatial filtering and (iv) negative feedback control to remove the low frequency fluctuations. The wind farm output then has the quality to be sold as regulated power which fetches a better economic return than when sold as energy. This, of course, presumes that 1-hour ahead prediction of wind velocity at 1-hour long low variance is available. / The thesis also considers the case when the conditions for regulated power are not predicted. In this situation, the wind farm may opt to use the tracking mode which tracks the slowly time varying non-turbulent wind power. The thesis examines the possibility of diverting some of the wind farm power to implement dynamic performance enhancement strategies, for system damping for example. / The controllability of the wind farm is demonstrated by simulations of a wind farm made up of 24 wind turbine-generators (WTGs) using 1-hour long wind velocity data.