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The invention is directed to a method for operating a wind turbine in the event of a grid error. The wind turbine has a rotor having a rotor blade adjustable in its blade pitch angle, a generator and a unit for capturing an actual value of the rotational speed of the generator, a value of the blade

The invention is directed to a method for operating a wind turbine in the event of a grid error. The wind turbine has a rotor having a rotor blade adjustable in its blade pitch angle, a generator and a unit for capturing an actual value of the rotational speed of the generator, a value of the blade pitch angle and an actual value of a variable which is representative of a generator torque. The method includes recognizing a grid error; capturing the actual value of the generator torque and actual value of rotational speed of the generator when a grid error was recognized; determining a change in torque; capturing the pitch angle; determining a corrective value for the pitch angle in dependence upon the change in the generator torque and the value for the pitch angle; and, determining a corrected set-point for the pitch angle.

대표청구항 ▼

1. A method for operating a wind turbine in the event of a grid error, wherein the wind turbine has a rotor having at least one rotor blade which can be adjusted in its blade pitch angle, a generator connected to the rotor for the generation of electrical power (P) and at least one unit for capturin

1. A method for operating a wind turbine in the event of a grid error, wherein the wind turbine has a rotor having at least one rotor blade which can be adjusted in its blade pitch angle, a generator connected to the rotor for the generation of electrical power (P) and at least one unit for capturing an actual value of the rotational speed of the generator (na), a value for the blade pitch angle (βa, βs) and an actual value of a variable which is representative of a generator torque (MG), said method comprising the steps of: recognizing a grid error;capturing an actual value of the variable representative of the generator torque (MG) and the actual value of the rotational speed of the generator (ns) when a grid error is recognized;determining a change in the generator torque (ΔMG);capturing the value for the blade pitch angle βa, βs);determining a corrective value for the blade pitch angle in dependence upon the change of the generator torque (ΔMG) and the value for the blade pitch angle (βa, βs); and,determining a corrected set-point for the blade pitch angle which results from a rotational speed dependent set-point for the blade pitch angle during a regular operation and the determined corrective value for the blade pitch angle. 2. The method of claim 1, wherein the actual value of a variable representative of the generator torque (MG) is one of an actual value of a generated active power (Pa) and of an active current (Ia). 3. The method of claim 1, wherein the recognition of the grid error takes place in dependence upon at least one of a change in a grid voltage (ΔU), a change in a grid frequency (Δf), an error message of a converter, and an error message of the generator. 4. The method of claim 1, wherein the recognition of the grid error takes place in dependence upon an error message which is generated in at least one of a converter and the generator. 5. The method according to claim 1, wherein an actual value of the blade pitch angle is captured. 6. The method of claim 1, wherein a set-point of the blade pitch angle is captured. 7. The method of claim 1, wherein: one of the actual value and the set-point for the blade pitch angle is captured; and,said corrective value for the blade pitch angle is determined in dependence upon the change in generator torque (ΔMG) and one of said actual value of said blade pitch angle (βa, βs) and said set-point for the blade pitch angle (βa, βs). 8. The method of claim 1, wherein the corrective value for the blade pitch angle is determined as an angle (βFRT). 9. The method of claim 1, wherein the corrective value for the blade pitch angle is determined as a rate of change of an angle (dβFRT/dt). 10. The method of claim 1, wherein the corrective value for the blade pitch angle is limited in such a manner that a maximum rate of change for the blade pitch angle is not exceeded. 11. The method of claim 1, wherein the rotational speed dependent set-point for the blade pitch angle is controlled in dependence upon an actual value and a set-point of the rotational speed in a regular operation. 12. The method of claim 1, wherein the corrective value for the blade pitch angle is applied after the recognition of a grid error. 13. A wind turbine comprising: a rotor having at least one rotor blade configured to be adjustable in a blade pitch angle;a blade pitch control configured to determine a rotational speed-dependent set-point for setting said blade pitch angle for said rotor blade;a generator connected to said rotor and configured to generate electrical power for an electrical supply grid and to develop a generator torque;a control unit configured to determine a change in the generator torque in response to a grid error and transmit a corrective value for the blade pitch angle in dependence upon said change in said generator torque and a value for said blade pitch angle to said blade pitch control; and,said blade pitch control being configured to set said blade pitch angle in correspondence to a corrected set-point which results from said rotational speed-dependent set-point for said blade pitch angle for regular operation and said corrective value for said blade pitch angle. 14. The wind turbine of claim 13, wherein said corrective value for said blade pitch angle is limited in such a manner that a maximum rate of change for said blade pitch angle is not exceeded.