SYSTEM AND METHOD FOR CONTROLLING BLADE PITCH ON WIND TURBINE ROTOR BLADES TO REDUCE VIBRATIONS AND LIMIT LOADS IN A LOCKED CONDITION OF THE TURBINE ROTOR

A proactive method and related wind turbine system are provided for reducing vibrations in the rotor blades when the rotor hub is locked against rotation. The method includes determining an initial blade orientation to wind direction and wind parameters for wind impacting the rotor blades. Based on the wind parameters and blade orientation, an angle of attack is determined for the rotor blades that will at least reduce vibrations expected to be induced in the blades from the current wind conditions. With a controller, the rotor blades are pitched to achieve the angle of attack using a pitch control system. The angle of attack is determined and the rotor blades are pitched from the initial blade orientation to the new angle of attack prior to vibrations being induced in the rotor blades.