METHOD AND ARRANGEMENT FOR DETECTING A BLADE PITCH ANGLE UNBALANCE OF A ROTOR BLADE SYSTEM OF A WIND TURBINE

摘要

A method is provided for detecting a blade pitch angle unbalance of a rotor blade system of a wind turbine, the rotor blade system rotating around a rotor rotation axis. The method includes yawing the rotor rotation axis about a yawing axis transverse to the rotor rotation axis. The method also includes obtaining a load signal indicative of a load due to the yawing. The method further includes analyzing the load signal regarding a frequency component of the load signal, and detecting the blade pitch angle unbalance based on the analyzed load signal.