A wind turbine with a sensor that measures the out-of-plane deflection of the blades and a controller that uses the signal from the sensor to determine the risk of a tower strike. The controller takes any necessary action to prevent a tower strike when it determines that the risk of a strike is high. The sensor can include strain gages or accelerometers mounted on the blades or it can include a fixed sensor mounted on the side of the tower to measure tower clearance as the blade passes by. The control action taken can include pitching blades, yawing the nacelle, or stopping the turbine. The controller is preferably a fuzzy logic controller.

This relates to a wind power installation comprising a pylon (tower) and a rotor arranged on the pylon and having at least one individually adjustable rotor blade. The wind power installation further comprises a device to detect the wind direction, a device to detect the azimuthal position and/or a device to detect the deviation from vertical of the pylon (tower). In one embodiment, a control unit is coupled to the rotor blade to adjust an angle of incidence of the at least one adjustable rotor blade using information which is representative of (i) the wind direction, (ii) the azimuthal position of the rotor, and (iii) the deviation from vertical of the pylon. The rotor blade may be adjusted in dependence on a deviation between the ascertained wind direction and the detected azimuthal position.