Method for operating a wind turbine

• US 7,462,947 B2
• Filed: 11/15/2006
• Issued: 12/09/2008
• Est. Priority Date: 04/20/2001
• Status: Expired due to Term

• Current Assignee: Aloys Wobben
• Original Assignee: Aloys Wobben
• Inventors: Wobben, Aloys
• Primary Examiner(s): Schuberg; Darren
• Assistant Examiner(s): Cuevas; Pedro J
• Application Number:
  US11/600,703
• Publication Number:
  US 20070063519A1
• Time in Patent Office: 755 Days
• Field of Search: 290/44
• US Class Current: 290/44
• CPC Class Codes: F03D 17/00 Monitoring or testing of wind motors, e.g. diagnostics testing during commissioning of wind motors F03D13/30
• CPC Class Codes: F03D 7/0284 in relation to the state of the electric grid
• CPC Class Codes: F03D 7/042 by means of an electrical or electronic controller
• CPC Class Codes: F03D 9/255 connected to electrical distribution networks; Arrangements therefor
• CPC Class Codes: F05B 2270/1033 Power (if explicitly mentioned)
• CPC Class Codes: F05B 2270/1071 in particular sudden load loss
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction

Abstract

A system and method for operating a wind turbine with a generator, drivable by a rotor, for supplying electrical power to an electric load, in particular an electric grid, are disclosed. Briefly described, one embodiment generates electrical power from an electrical generator coupled to the wind turbine, outputs the generated electrical power to an electric grid, senses a disruption in the electric grid, maintains connection of the electrical generator during the disruption, and limits the generated electrical power during at least a portion of the disruption.

Claims

1. A method for operating a wind turbine, comprising:

generating electrical power from an electrical generator coupled to the wind turbine;

outputting the generated electrical power to an electric grid from a regulating device coupled to the generator;

sensing a fault in the electric grid with a sensor;

maintaining connection of the electrical generator to the electric grid to provide some power to the electric grid during the fault;

limiting the generated electrical power provided to the electric grid from the regulating device during at least a portion of the fault; and

resuming normal delivery of electrical power to the grid after functionality of the grid is restored.

2. The method of claim 1, further comprising:

regulating the generated electrical power provided to the electric grid during at least the portion of the fault to an amount less than the electrical power output to the electric grid before the disruption occurs.

3. The method of claim 1 wherein the generated electrical power is characterized by a current, the method further comprising:

regulating the current during at least the portion of the fault to an amount less than the current output to the electric grid before the fault occurs.

4. The method of claim 1 wherein the generated electrical power is characterized by a reactive current, the method further comprising:

regulating the reactive current during at least the portion of the fault to an amount less than the reactive current output to the electric grid before the fault occurs.

5. The method of claim 1, further comprising:

increasing the generated electrical power provided to the electric grid after conclusion of the fault.

6. The method of claim 1, further comprising:

regulating the generated electrical power output provided to the electric grid during at least the portion of the fault in accordance with at least a power gradient dP/dt.

7. The method of claim 1 further comprising:

sensing a change in a frequency of the electric grid during the fault; and

regulating the generated electrical power provided to the electric grid during at least the portion of the fault in accordance with the sensed frequency change.

8. The method of claim 1 wherein the electrical power output provided to the electric grid is characterized as an alternating current (AC) power with a frequency, and wherein the frequency is substantially equal to an electric grid frequency.

9. The method of claim 1 wherein the generated electrical power is characterized by a phase position, the method further comprising:

regulating the phase position during at least the portion of the fault to an amount less than the phase position before the fault occurs.

10. The method of claim 1 wherein the electric grid is a multiphase system, and wherein the generated electrical power is characterized by at least an amount of current, a phase position, and/or a proportion of reactive current for each phase of the multiphase system, the method further comprising:

limiting for at least one phase of the multiphase system the amount of current, the phase position, and/or the proportion of reactive current during at least the portion of the fault.

11. The method of claim 10 wherein the limiting comprises:

independently limiting for each phase of the multiphase system the amount of current, the phase position, and/or the proportion of reactive current during at least the portion of the fault.

12. The method of claim 1 wherein maintaining connection of the electrical generator during the fault comprises:

maintaining connection of the electrical generator to provide some power to the electric grid during the fault when the fault is a short circuit characterized by a grid voltage deviation of more than 20%.

13. The method of claim 1 wherein the fault is characterized by a grid voltage deviation of more than 20% from a reference value.

14. The method of claim 1, further comprising:

sensing a voltage; and

limiting a reactive component of the generated electrical power in accordance with the sensed voltage during at least the portion of the fault.

15. The method of claim 1, further comprising:

limiting a power factor of the generated electrical power during at least the portion of the fault.

16. The method of claim 1 wherein the fault is a short circuit.

17. A wind turbine, comprising:

a rotor;

an electrical generator coupled to the rotor and operable to generate power into an electric grid;

a sensor operable to sense a fault on the electric grid; and

a regulating device operable to regulate the generated power into the electric grid to a reduced amount during at least a portion of the fault, while providing power above a selected amount during the fault.

18. The wind turbine of claim 17 wherein the electrical generator remains connected to the electric grid during the fault.

19. The wind turbine of claim 17 wherein the reduced amount of the generated power into the electric grid is less than an amount of power generated before the fault occurs.

20. The wind turbine of claim 17 wherein the sensor comprises:

a frequency sensor operable to sense a change in frequency of the electric grid such that the regulating device regulates the generated power into the electric grid in accordance with the sensed frequency change.

21. The wind turbine of claim 17, further comprising:

a current sensor operable to sense a change in an amount of current output to the electric grid from the electrical generator such that the regulating device regulates the generated power into the electric in accordance with the sensed current change.

22. The wind turbine of claim 17, further comprising:

a means for detecting a short circuit in the electric grid.

23. The wind turbine of claim 17 wherein the sensor is coupled to the grid.

24. The wind turbine of claim 17 wherein the sensor is coupled to the regulating device.

25. The wind turbine of claim 17 wherein the sensor is coupled to the generator.