Extreme Wind Speeds and Their Prediction for Wind Turbines

The precise knowledge of occurrence of extreme wind speed for wind turbine design is of utmost importance. This paper describes the extreme value theory, especially the Fisher-Tippett generalized extreme value distributions. On this basis, Gumbel's hypothesis that merely recording of annual extreme events for a duration of ten years or more can provide the probability of occurrence of an extreme event (maximum or minimum). Gumbel's cumulative distribution function (two parameter function) provides the exceedances of wind speed from a given value. The fitting of a regression to the data provides the unknown parameters. However, at the extreme end of the plot, the function is biased. This has been corrected by Gringorten method. The work also calculates the mean recurrence interval of, say, occurrence of a 50-year wind. The proposed methodology to estimate extreme wind speed is simple and straightforward. It is hoped that its use would be a valuable tool in designing wind turbines.