Lidar-assisted Extreme Load Reduction by Multi-variable Protective Derating

Abstract

Lidar-assisted control of wind turbines has been an active field of research during the last years and has recently become more attention from industry, as well. The potential of lidar-assisted feed-forward controllers is shown in various simulation studies and proven in first field-testings. This work aims to further push forward the application of lidar-assisted control by introducing a method to bring the wind turbine to a different operating point, when a lidar detects an approaching extreme gust. The method reduces the power output of the wind turbine while keeping the rotor rotation constant. This is achieved by a synchronous multi-variable feed-forwarding of the generator torque and the pitch angle. In combination with a classical lidar-assisted feed-forward controller, this leads to further reduced structural loads under the impact of an extreme gust. The method is tested with a coherent and a corresponding turbulent gust.