Wind direction fluctuation analysis for wind turbines

Fluctuations are a key characteristic of the wind resource. It is important to quantitatively analyze wind direction fluctuation due to its influence on the optimization of wind turbine yaw control. Based on wind resource data available from SCADA systems, a method is proposed to describe wind direction fluctuations in terms of fluctuation amplitude A and fluctuation duration T. A Weibull distribution is employed to fit the marginal probability density of both these two measures of wind direction fluctuations, and a mixed Copula used to connect the marginal distributions, establishing the joint probability density function. This representation has been verified through comparison with the real operating SCADA data. A set of indicators are extracted from the probability distribution which can accurately quantify the local wind direction fluctuation characteristics of a wind turbine. These indicators can be helpful in the optimization of the yaw control system parameters, facilitating an improvement in the power generating performance of the wind turbine.