Patent ID: 8779611

Claim:
A method for operating a pitch-controlled wind turbine having a rotor blade, a rotor and a generator, the method comprising the steps of: prescribing a set-point value for the generator torque (M) in dependence upon a rotational speed (n) of the generator or of the rotor; providing a transition point (n 3 , M 3 ) whereat a transition occurs from a partial-load operation into a nominal-load operation wherein said rotational speed (n) is controlled by adjusting the pitch angle of said rotor blade; determining the values (n 3 , M 3 ) of said transition point in dependence upon a current value of the air density (ρ); with falling air density, increasing the rotational speed (n 3 ) and/or reducing said set-point value (M 3 ) for the generator torque; determining a change (Δρ) in said air density (ρ) and comparing said change (Δρ) to a maximum allowable change (Δρ 2 ) in air density; and, if said change (Δρ) in air density (ρ) exceeds said maximum allowable change (Δρ 2 ), then changing said transition point.