Determination of stationary and dynamical power curves using a nacelle-based lidar system

Abstract

This paper investigates the determination of stationary and dynamical power curves using a nacelle-based lidar system. Wind speed measurements on one of the REpower 5MW turbines at the German offshore test site "alpha ventus" were carried out with a pulsed lidar system that is capable of measuring the wind field at different measurement planes over the rotor swept area. The results show that the stationary lidar-based power curve has a small scatter but is shifted towards lower wind speeds compared to a conventional power curve measured with a cup anemometer from a met mast. The new approach of calculating dynamical power curves shows short-time dynamics of the turbine and allows a quick detection of changes such as the icing of an anemometer or the reduction in the maximum power output of the wind turbine.