Method for operating a wind energy plant

• US 7,462,946 B2
• Filed: 04/12/2002
• 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:
  US10/475,531
• Publication Number:
  US 20040207206A1
• Time in Patent Office: 2,433 Days
• Field of Search: 290/44
• US Class Current: 290/44
• 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: F05B 2270/335 Output power or torque
• CPC Class Codes: F05B 2270/337 Electrical grid status parameters, e.g. voltage, frequency or power demand
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction

Abstract

The present invention relates to a method for operating a wind turbine with a generator, drivable by a rotor, for supplying electrical power to an electrical load, in particular an electric grid. In order to compensate for fluctuations in the grid as far as possible, the system of the kind initially specified is developed in such a way that the power delivered to the load by the generator is regulated in response to a current outputted to the load.

Claims

1. A method for operating a power system comprising:

generating electrical power with an electrical generator of a wind power installation driven by a rotor to output the electrical power to an electrical grid;

sensing an electrical current of the electrical power outputted to the electrical grid to detect a fault in the grid;

maintaining connection of the wind power installation to the grid during the fault to continue to supply electrical current to the grid from the wind power installation during the fault;

limiting the electrical current delivered by the wind power installation to the grid during the fault to less than a selected amount;

controlling the wind power installation from a control station distant from the wind power installation to remotely adjust the amount of electrical current delivered by the wind power installation to the grid during the fault; and

resuming normal function of the wind power installation when the fault is no longer in the grid.

2. The method of claim 1, further comprising:

regulating the electrical power outputted by the generator to a load in response to an amount of current outputted to the load.

3. The method of claim 1,

wherein the electrical current is an alternating current with a predefinable frequency.

4. The method of claim 3,

wherein the predefinable frequency is substantially equal to a frequency of the grid.

5. The method of claim 1,

wherein the outputted power does not exceed a predefinable amount, has a predefinable phase position and includes a predefinable proportion of reactive current.

6. The method of claim 5,

wherein the power system is a multiphase system and phase position and a proportion of reactive current for each phase do not exceed a predefinable value.

7. The method of claim 6,

wherein for each phase a value independent of other phases can be predefined.

8. The method of claim 1,

wherein the electrical current is limited for every phase affected by a short circuit to a momentary value at a moment the short circuit occurs.

9. The method of claim 1 wherein the fault corresponds to a grid voltage reaching a value that deviates by more than 20% from a reference value.

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

11. The method of claim 1, further comprising:

limiting the electrical power outputted to the electrical grid to at least a predefinable amount of electrical power.

12. The method of claim 1, further comprising:

limiting the electrical power outputted to the electrical grid to at least a predefinable phase position.

13. The method of claim 1, further comprising:

limiting the electrical power outputted to the electrical grid to at least a predefinable proportion of reactive current.

14. The method of claim 1 wherein the fault is a grid voltage fault.

15. The method of claim 1 wherein the fault is a phase position fault.

16. A power system, comprising:

a wind power installation including;

an electrical generator coupled to a rotor to output electrical power to an electrical grid;

a sensor operable to detect a fault in the grid;

a regulating device configured to maintain connection of the wind power installation to the grid during the fault and to continue to supply a limited current from the wind power installation to the grid during the fault; and

an external command input; and

a control station remote from the wind power installation operable to adjust the limited current during the fault by commands given to the external command input of the wind power installation.

17. The power system of claim 16, wherein the regulating device of the wind power installation includes:

a microprocessor operable to compare a sensed electrical current outputted to the grid with a selected current value.

18. The power system of claim 16 wherein the external command input transfers data to the regulating device.

19. The power system of claim 16 wherein the sensor of the wind power installation includes:

a device to detect a short circuit in the grid.

20. The power system of claim 19 wherein the sensor of the wind power installation comprises:

a voltage sensing device to detect a voltage of at least one phase in the grid.

21. The power system of claim 19 wherein the sensor of the wind power installation comprises:

a phase monitor to detect a phase position of currents and voltages of at least one phase in the grid.

22. The power system of claim 16 wherein the fault is a short circuit, and

wherein the electrical generator remains connected to the grid when the short circuit occurs.

23. The power system of claim 18, wherein:

control signals are received via the external command input from a grid operator, and in response to said control signals from the grid operator the wind power installation is controlled in response to needs of the grid operator and hence that electrical power, including a non-reactive power, a wind power, a current position, a voltage position or a phase position, is fed into the grid in a form as required by the grid operator.

24. The power system of claim 16, wherein the fault corresponds to a grid voltage reaching a value that deviates by more than 20%.

25. The power system of claim 16 wherein the wherein the fault is a short circuit.

26. The power system of claim 16 wherein the wind power installation remains connected to the grid when a grid voltage reaches a value that deviates by more than 20% from a reference value.

27. The power system of claim 16 wherein the wind power installation remains connected to the grid when a grid voltage reaches a value that deviates by more than 40% from a reference value.

28. The power system of claim 16, comprising:

a rectifier coupled to the generator and operable to rectify alternating current (AC) power produced by the generator to direct current (DC) power; and

an inverter coupled between the rectifier and the grid and operable to convert the DC power to AC power with a frequency corresponding to a grid frequency.

29. The power system of claim 28, comprising:

a microprocessor operable to control at least the inverter, wherein the inverter is controlled so that at least the electrical current of the electrical power output to the electrical grid does not exceed a selected value.

30. A method for operating a wind turbine comprising:

generating electrical power from a generator coupled to a rotor and driven by wind;

outputting the electrical power from the wind turbine to an electrical grid;

detecting a fault in the electrical grid based upon a sensed parameter; and

regulating the electrical power output to the electrical grid such that at least an electrical current of the electrical power output to the electrical grid does not exceed a selected amount, and such that the wind turbine remains operable and connected to the electrical grid so that the electrical power is output to the electrical grid during the fault;

controlling the amount of power supplied by the wind turbine to the grid by commands submitted to an external command input of the wind power turbine from a control center remote from the wind power turbine; and

resuming normal function of the wind turbine when the fault is no longer on the grid.

31. The method of claim 30, wherein the sensed parameter is a grid voltage.

32. The method of claim 30, wherein the sensed parameter is a phase position of a phase of the grid.

33. The method of claim 30, further comprising:

sensing a grid voltage deviation of more than 20% from a reference value to determine the occurrence of the substantial disruption.

34. The method of claim 30, further comprising:

sensing a grid voltage deviation of more than 40% from a reference value to determine the occurrence of the substantial disruption.

35. The method of claim 30, further comprising:

sensing an electrical current of the electrical power output to the electrical grid such that regulating the electrical power is based upon the sensed electrical current.

36. The method of claim 30, further comprising:

sensing a grid frequency of the electrical power output to the electrical grid such that regulating the electrical power is based upon the sensed grid frequency.

37. The method of claim 30 further comprising:

sensing an amount of the electrical power output to the electrical grid such that regulating the electrical power is based upon the sensed power amount.

38. The method of claim 30, further comprising:

sensing a power gradient of the electrical power output to the electrical grid such that regulating the electrical power is based upon the sensed power gradient.

39. The method of claim 30, further comprising:

sensing a power factor of the electrical power output to the electrical grid such that regulating the electrical power is based upon the sensed power factor.

40. The method of claim 30, further comprising:

rectifying an alternating current (AC) power produced by the generator of the wind turbine to direct current (DC) power;

converting the DC power to AC power with a frequency corresponding to a grid frequency; and

monitoring a parameter associated with the AC power output to the grid such that at least the electrical current of the generator does not exceed a selected generator current value during the fault.

41. The method of claim 30, further comprising:

sensing a short circuit on the grid to determine occurrence of the fault.