Method for the emergency braking of a wind power plant and a wind power plant with a rotor blade pitch control for emergency braking

1. A method for the emergency braking of a wind turbine, in which at least one rotor blade of the wind turbine is adjusted into its feathering position, characterized by: a first phase, in which the at least one rotor blade is adjusted with a first speed, and a second phase, in which the at least one rotor blade is adjusted as of a first predetermined blade pitch angle with a second speed, which is increased until a maximum speed is reached and/or until a second predetermined blade pitch angle is reached.

2. The method according to claim 1 , characterized in that the first speed is constant in the first phase.

3. The method according to claim 1 , characterized in that the second speed is increased continuously or gradually in the second phase.

4. The method according to claim 1 , characterized in that the first predetermined blade pitch angle lies in an area, in which there are lower loads on the rotor blade than at the beginning of the pitch control process.

5. The method according to claim 1 , characterized in that the first predetermined blade pitch angle has a value of 30° to 50°.

6. The method according to claim 1 , characterized in that as of a third predetermined blade pitch angle, which is smaller than the first predetermined blade pitch angle, the speed for the pitch control of the rotor blade is reduced in a third phase.

7. The method according to claim 6 , characterized in that the third predetermined blade pitch angle is 10° to 20° smaller than the first predetermined blade pitch angle.

8. A wind turbine with at least one rotor blade and a pitch system comprising a pitch control for adjusting the at least one rotor blade, the pitch control comprising a brake program, the brake program beginning upon receipt of a control signal for an emergency braking, the brake program comprising instructions to move the at least one rotor blade into its feathering position, characterized in that the instructions to move the at least one rotor blade into its feathering position include instructions to:

adjust the rotor blade with a first speed in a first phase, and

as of a first predetermined blade pitch angle adjust the rotor blade in a second phase with a second speed, which is increased until a maximum speed is reached and/or a second predetermined blade pitch angle is reached.

9. The wind turbine according to claim 8 , characterized in that the first speed is constant in the first phase.

10. The wind turbine according to claim 8 , characterized in that the second speed is increased continuously or gradually in the second phase.

11. The wind turbine according to claim 8 , characterized in that the first predetermined blade pitch angle lies in an area, as of which there are lower loads on the rotor blade, in particular between 30° and 50°.

12. The wind turbine according to claim 8 , characterized in that the instructions of the brake program further include instructions to, as of a third predetermined blade pitch angle which is smaller than the first predetermined blade pitch angle, reduce the speed for the pitch control of the rotor blade in a third phase.

13. The wind turbine according to claim 12 , characterized in that there is a constant speed in the third phase.

14. The wind turbine according to claim 12 , characterized in that the third predetermined blade pitch angle is 10° to 20° smaller than the first predetermined blade pitch angle.

15. The wind turbine according to claim 8 , characterized in that the instructions of the brake program further include instructions to reduce the speed when the second predetermined blade pitch angle is reached.

16. The wind turbine according to claim 8 , wherein the brake program ends when the feathering position is reached.