Impact of Short Duration Wind Variations on Output of a Pitch Angle Controlled Turbine

The distorted output of a pitch angle controlled (PAC) horizontal axis turbine, as influenced by short duration wind variations like turbulence and gusts, is analyzed under the assumption of two-parameter Weibull statistics. The well accepted concept of turbulence intensity is used as a parametric measure of short duration wind variations. Analytical expressions are formulated and used to estimate the short duration aggregate power output from a turbine, together with the fractional deviations from corresponding ideal zero-turbulence values. Operating conditions of constant turbulence intensity, and constant wind speed standard deviation, are considered separately for the studies. Sensitivity of turbine output power to cut-in and rated values of wind speed are evaluated and discussed.