Method for operating a wind energy plant and wind energy plant

Abstract

A method for operating a wind energy plant having a rotor with at least one rotor blade which has an adjustable pitch angle and a generator coupled to the rotor, and a regulation means which, if a there is a deviation of the rotation speed of the generator or rotor from a rotation speed set point, adjusts the pitch angle of the at least one rotor blade such that the rotation speed set point is reached again, wherein an electrical quantity provided by the wind energy plant by means of a generator and fed into a grid is reduced to a predetermined value in a short time by a reduction of a preset value for the generator, wherein prior to the regulation means noticing a deviation of the rotation speed of the rotor or generator from the rotation speed set point effected by the reduction of the preset value, an adjustment of the at least one rotor blade to a new pitch angle is initiated, wherein at the new pitch angle the rotation speed of the rotor or the generator reaches the rotation speed set point at the reduced electrical quantity and the current wind speed.

What is claimed is: 
     
       1. Method for operating a wind energy plant, the wind energy plant having a rotor with at least one rotor blade which has an adjustable pitch angle, the wind energy plant having a generator coupled to the rotor, and a regulation means which, if there is a deviation of the rotation speed of the generator or rotor from a rotation speed set point, adjusts the pitch angle of the at least one rotor blade such that the rotation speed set point is reached again, wherein an electrical quantity provided by the wind energy plant by means of a generator and fed into a grid is reduced to a predetermined value in a short time by reduction of a preset value for the generator, characterized in that prior to the regulation means ( 12 ) noticing a deviation of the rotation speed of the rotor or generator (n GI ) from the rotation speed set point (n GS ) effected by the reduction of the preset value, an adjustment of the at least one rotor blade to a new pitch angle (ν) is initiated, wherein at the new pitch angle (ν) the rotation speed of the rotor or generator (n GI ) reaches the rotation speed set point at the reduced electrical quantity (P 1 , P 2 , P 3 , P 4 , P 5 ) and the current wind speed (V Wind ). 
     
     
       2. Method according to  claim 1 , characterized in that the preset value is a preset generator torque or a preset generator power. 
     
     
       3. Method according to  claim 1 , characterized in that the electrical quantity (P 1 , P 2 , P 3 , P 4 , P 5 ) is the active power (P 1 , P 2 , P 3 , P 4 , P 5 ) of the wind energy plant. 
     
     
       4. Method according to  claim 1 , characterized in that the new pitch angle (ν) is adjusted by way of reducing a rotation speed set point (n GS ) supplied to the regulation means ( 12 ) by a defined offset. 
     
     
       5. Method according to  claim 4 , characterized in that the offset is reduced over time to zero starting from an initial maximum value. 
     
     
       6. Method according to  claim 4 , characterized in that the offset is determined by means of a characteristic diagram. 
     
     
       7. Method according to  claim 4 , characterized in that the offset is determined by means of at least one function. 
     
     
       8. Method according to  claim 1 , characterized in that the new pitch angle (ν) is adjusted by way of increasing a current rotation speed (n GI ) supplied to the regulation means ( 12 ) by a defined offset. 
     
     
       9. Method according to  claim 1 , characterized in that the new pitch angle (ν) is adjusted by way of increasing a minimal pitch angle supplied to the regulation means ( 12 ) by a defined offset. 
     
     
       10. Method according to  claim 1 , characterized in that the adjustment to the new pitch angle (ν) is initiated only if the rotation speed of the rotor or generator (n GI ) is above a threshold rotation speed and/or if the preset value prior to its reduction is above a threshold preset value. 
     
     
       11. Wind energy plant having a rotor with at least one rotor blade which has an adjustable pitch angle, the wind energy plant having a generator coupled to the rotor, a regulation means designed to adjust the pitch angle of the at least one rotor blade such that, if there is a deviation of the rotation speed of the generator or rotor from a rotation speed set point, the rotation speed set point is reached again, and a control means designed to reduce an electrical quantity which is provided by the wind energy plant by means of a generator and fed into a grid to a predetermined value in a short time by reduction of a preset value for the generator, characterized in that the control means ( 22 ) is designed to initiate an adjustment of the at least one rotor blade to a new pitch angle (ν) prior to the regulation means ( 12 ) noticing a deviation of the rotation speed of the rotor or generator (n GI ) from the rotation speed set point (n GS ) effected by the reduction of the preset value, wherein at the new pitch angle (ν) the rotation speed of the rotor or generator (n GI ) reaches the rotation speed set point (n GS ) at the reduced electrical quantity (P 1 , P 2 , P 3 , P 4 , P 5 ) and the current wind speed (V Wind ). 
     
     
       12. Wind energy plant according to  claim 11 , characterized in that the preset value is a preset generator torque or a preset generator power. 
     
     
       13. Wind energy plant according to  claim 11 , characterized in that the electrical quantity (P 1 , P 2 , P 3 , P 4 , P 5 ) is the active power (P 1 , P 2 , P 3 , P 4 , P 5 ) of the wind energy plant. 
     
     
       14. Wind energy plant according to  claim 11 , characterized in that the control means ( 22 ) is designed to adjust the new pitch angle (ν) by way of reducing a rotation speed set point (n GS ) supplied to the regulation means ( 12 ) by a defined offset. 
     
     
       15. Wind energy plant according to  claim 14 , characterized in that a characteristic diagram for determining the offset is retained in the control means ( 22 ). 
     
     
       16. Wind energy plant according to  claim 14 , characterized in that at least one function for calculating the offset is retained in the control means ( 22 ). 
     
     
       17. Wind energy plant according to  claim 11 , characterized in that the control means ( 22 ) is designed to adjust the new pitch angle (ν) by way of increasing a current rotation speed (n GI ) supplied to the regulation means ( 12 ) by a defined offset. 
     
     
       18. Wind energy plant according to  claim 11 , characterized in that the control means ( 22 ) is designed to adjust the new pitch angle (ν) by way of increasing a minimal pitch angle supplied to the regulation means ( 12 ) by a defined offset. 
     
     
       19. Wind energy plant according to  claim 11 , characterized in that the control means ( 22 ) is designed to reduce the offset over time to zero starting from an initial maximum value. 
     
     
       20. Wind energy plant according to  claim 11 , characterized in that the control means ( 22 ) has a comparison means for comparing the rotation speed of the rotor or generator (n GI ) to a threshold rotation speed and in that the control means ( 22 ) is designed to initiate the adjustment to the new pitch angle (ν) only if the rotation speed of the rotor or generator (n GI ) is above a threshold rotation speed and/or if the preset value prior to its reduction is above a threshold preset value. 
     
     
       21. A method for operating a wind energy plant, the wind energy plant having a rotor with at least one rotor blade which has an adjustable pitch angle, the wind energy plant having a generator coupled to the rotor, and a regulation means for adjusting the pitch angle of the at least one rotor blade, the wind energy plant providing an electrical quantity to a grid, the method comprising:
 reducing the electrical quantity to a reduced electrical quantity in a short time period,   adjusting the at least one rotor blade to a new pitch angle (ν) when a reduction to the reduced electrical quantity is initiated, wherein a rotation speed of the rotor or generator (n GI ) at the new pitch angle (ν) reaches a rotation speed set point of the rotor or generator (n GS ) at the reduced electrical quantity and current wind speed (V Wind ), wherein the rotation speed set point is at least equal to a nominal rotation speed of the generator or rotor.    
     
     
       22. The wind energy plant of claim 21, wherein the short time period is less than a minute.  
     
     
       23. The method according to claim 21, characterized in that the electrical quantity is an active power (P1, P2, P3, P4, P5) of the wind energy plant.  
     
     
       24. A wind energy plant configured to feed an electrical quantity into an electric grid, the wind energy plant comprising:
 a rotor with at least one rotor blade with an adjustable pitch angle;   a generator coupled to the rotor;   a regulation means for adjusting the pitch angle of the at least one rotor blade;   a control means, the control means configured to reduce the electrical quantity to a reduced electrical quantity in a short time period and to adjust the at least one rotor blade to a new pitch angle (ν) when the reduction of the electrical quantity to the reduced electrical quantity is initiated, wherein a rotation speed of the rotor or generator (n GI ) at the new pitch angle (ν) reaches a rotation speed set point of the rotor or generator (n GS ) at the reduced electrical quantity and current wind speed (V Wind ).    
     
     
       25. The wind energy plant of claim 24, wherein the short time period is less than a minute.  
     
     
       26. The method according to claim 24, characterized in that the electrical quantity is an active power (P1, P2, P3, P4, P5) of the wind energy plant.