Table of Contents
ISRN Renewable Energy
Volume 2011 (2011), Article ID 890582, 11 pages
Research Article

Time-Domain Modeling of Tower Shadow and Wind Shear in Wind Turbines

Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78712, USA

Received 11 July 2011; Accepted 31 July 2011

Academic Editors: W. E. Alnaser, M. Cheng, S. S. Kalligeros, and B. Mwinyiwiwa

Copyright © 2011 Swagata Das et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Tower shadow and wind shear contribute to periodic fluctuations in electrical power output of a wind turbine generator. The frequency of the periodic fluctuations is 𝑛 times the blade rotational frequency 𝑝 , where 𝑛 is the number of blades. For three-bladed wind turbines, this inherent characteristic is known as the 3 𝑝 effect. In a weak-power system, it results in voltage fluctuation or flicker at the point of common coupling of the wind turbine to the grid. The phenomenon is important to model so as to evaluate the flicker magnitude at the design level. Hence, the paper aims to develop a detailed time-domain upwind fixed speed wind turbine model which includes the turbine's aerodynamic, mechanical, electrical, as well as tower shadow and wind shear components. The model allows users to input factors such as terrain, tower height, and tower diameter to calculate the 3 𝑝 oscillations. The model can be expanded to suit studies involving variable speed wind turbines. Six case studies demonstrate how the model can be used for studying wind turbine interconnection and voltage flicker analysis. Results indicate that the model performs as expected.