Statistical analysis of flicker produced by wind farms with fixed speed asynchronous generators in continuous operation

摘要

Wind farms with fixed speed asynchronous generators generate periodic voltage fluctuations and flicker therefore mainly due to the so-called tower shadow effect. An analytical expression of the current supplied by the wind farm (and the voltage at the connection point) can be derived from a simplified model of the farm with a term that quantifies the relative fluctuation of the electrical variable considered. By its very nature, this term is a random variable since it is the result of the fluctuations introduced by each of the generators, and these depend on the angular positions of the individual turbines. In this paper, the authors, based on the aforementioned expression of the total current of the farm, have analyzed the resulting fluctuation phenomenon as a statistical problem by a new theoretical approach. This has allowed the calculation of the distribution and probability density functions as well as the mean values, the variance and the standard deviation, as expressions depending on the number of generators. Copyright © 2012 John Wiley & Sons, Ltd.