THE AVERAGE OUTPUT POWER OF A WIND TURBINE IN A TURBULENT WIND

Turbulence has an important influence on the average output power of a wind turbine taken over a certain period of time. The wind dynamics is coupled to the turbine dynamic characteristics and results in a fairly complicated behavior. Thus, the common ''static'' model of calculating the average power, which is based on the turbine power curve and the average wind speed, may result in increasing errors. This paper presents three different models for calculating the average output power, taking into account the dynamic characteristics of the phenomenon. These models include direct time integration using accurate wind data and a detailed dynamic model of the turbine, a quasi-steady approach which is much simpler to apply and takes into account the wind dynamics, and an improved efficient model that also includes the influence of the dynamic characteristics of the turbine. The last improved model is based on a study of the turbine response to a sinusoidal gust. All models are compared with field measurements in order to study their accuracy. The comparison exhibits the importance of including all the dynamic effects in the calculations.