Frequency-responsive wind turbine output control

• US 8,301,311 B2
• Filed: 07/06/2009
• Issued: 10/30/2012
• Est. Priority Date: 07/06/2009
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Nelson, Robert J.
• Primary Examiner(s): JARRETT, RYAN A
• Application Number:
  US12/497,772
• Publication Number:
  US 20110001318A1
• Time in Patent Office: 1,212 Days
• Field of Search: 700/287, 290/44, 290/55
• US Class Current: 700/287
• CPC Class Codes: F03D 7/0272 by measures acting on the electrical generator
• CPC Class Codes: F03D 7/0284 in relation to the state of the electric grid
• CPC Class Codes: F03D 7/043 characterised by the type of control logic
• CPC Class Codes: F03D 7/048 controlling wind farms
• CPC Class Codes: F05B 2270/1041 in particular the electrical frequency of driven generator
• CPC Class Codes: F05B 2270/309 Rate of change of parameters
• CPC Class Codes: F05B 2270/337 Electrical grid status parameters, e.g. voltage, frequency or power demand
• CPC Class Codes: H02J 3/472 For selectively connecting the AC sources in a particular order, e.g. sequential, alternating or subsets of sources
• CPC Class Codes: H02J 3/48 Controlling the sharing of the in-phase component
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction
• CPC Class Codes: Y02E 10/76 Power conversion electric or electronic aspects

Abstract

A wind farm (10) may include a plurality of variable speed wind turbines (12, 14, 16). A centralized controller (50) may be configured to selectively adjust a respective electrical output power from each of the wind turbines. The controller may include a monitor (52) configured to monitor a correlation between a deviation from a grid frequency and a wind power change. The controller may be configured to adjust a response of the electrical output power based on the monitored correlation. The electrical output power response may be configured to meet a grid frequency regulation notwithstanding of random occurrences of wind power changes.

Claims

1. A wind farm comprising:

a plurality of variable speed wind turbines; and

a centralized controller configured to selectively adjust a respective electrical output power from each of the wind turbines, wherein the controller includes a monitor configured to monitor over one or more periods of time a directional correlation between values corresponding to a deviation from a grid frequency and a wind power change, the controller configured to adjust a response of the electrical output power over the one or more periods of time for at least one of the wind turbines based on the monitored correlation between the values corresponding to the grid frequency deviation and the wind power change, the response of the electrical output power configured to meet a grid frequency regulation notwithstanding of random occurrences of wind power changes.

2. The wind farm of claim 1, wherein when the monitored directional correlation indicates over a respective period of time a positive correlation between values corresponding to a deviation from the grid frequency and a wind power change, then the output power response is adjusted over said respective period of time in accordance with a first control strategy.

3. The wind farm of claim 2, wherein when the monitored directional correlation indicates over a further period of time a negative correlation between values corresponding to a deviation from the grid frequency and a wind power change, then the output power response is adjusted over said further period of time in accordance with a second control strategy.

4. The wind farm of claim 3, wherein the first control strategy comprises a transition for the output power at a first rate of change, and wherein the second control strategy comprises a transition for the output power at a second rate of change, wherein the second rate change is higher than the first rate of change.

5. The wind farm of claim 4, wherein said first rate of change comprises ramping up or ramping down the electrical power output at a rate of 50% or less per minute with respect to a rated output power of the wind turbine.

6. The wind farm of claim 4, wherein said second rate of change comprises transitioning the output power at an average rate of 1% or more per second with respect to a rated output power of the wind turbine.

7. The wind farm of claim 2, wherein the first control strategy comprises a delayed transition for the output power.

8. The wind farm of claim 2, wherein the first control strategy comprises at least a transition segment where the output power transitions at a first rate of change and further comprises at least a delay segment where the output power is delayed by a predefined time delay.

9. The wind farm of claim 1, comprising a wind turbine implementation selected from the group consisting of a doubly-fed induction generator implementation, a direct-drive implementation, and a geared full-converter implementation.

10. A variable speed wind turbine comprising:

a controller configured to adjust an electrical output power from the wind turbine, wherein the controller includes a monitor configured to monitor over one or more periods of time a directional correlation between values corresponding to a deviation from a grid frequency and a wind power change, the controller configured to adjust a response of the electrical output power over the one or more periods of time based on the monitored directional correlation between the values corresponding to the deviation from the grid frequency and the wind power change, the response of the electrical output power configured to meet a grid frequency regulation notwithstanding of random occurrences of wind power changes.

11. The wind turbine of claim 10, wherein when the monitored directional correlation indicates over a respective period of time a positive correlation between values corresponding to a deviation from the grid frequency and a wind power change, then the output power response is adjusted over said respective period of time in accordance with a first control strategy.

12. The wind turbine of claim 11, wherein when the monitored directional correlation indicates over a further period of time a negative correlation between values corresponding to a deviation from the grid frequency and a wind power change, then the output power response is adjusted over said further period of time in accordance with a second control strategy.

13. The wind turbine of claim 12, wherein the first control strategy comprises a transition for the output power at a first rate of change, and wherein the second control strategy comprises a transition for the output power at a second rate of change, wherein the second rate change is higher than the first rate of change.

14. The wind turbine of claim 13, wherein said first rate of change comprises ramping up or ramping down the electrical power output at a rate of 50% or less per minute with respect to a rated output power of the wind turbine.

15. The wind turbine of claim 13, wherein said second rate of change comprises transitioning the output power at an average rate of 1% or more per second with respect to a rated output power of the wind turbine.

16. The wind turbine of claim 11, wherein the first control strategy comprises a delayed transition for the output power.

17. The wind turbine of claim 11, wherein the first control strategy comprises at least a transition segment where the output power transitions at a first rate of change and further comprises at least a delay segment where the output power is delayed by a predefined time delay.

18. The wind turbine of claim 10, comprising a wind turbine implementation selected from the group consisting of a doubly-fed induction generator implementation, a direct-drive implementation, and a geared full-converter implementation.

19. A method for controlling a variable speed wind turbine comprising:

adjusting an electrical output power from the wind turbine;

monitoring over one or more periods of time a directional correlation between values corresponding to a deviation from a grid frequency and a wind power change; and

adjusting a response of the electrical output power over the one or more periods of time based on the monitored directional correlation between the values corresponding to the deviation from the grid frequency and the wind power change, wherein the response of the electrical output power is configured to meet a grid frequency regulation notwithstanding of random occurrences of wind power changes.

20. The method of claim 19, wherein when the monitored directional correlation indicates over a respective period of time a positive correlation between values corresponding to a deviation from the grid frequency and a wind power change, adjusting the output power response over said respective period of time in accordance with a first control strategy.

21. The method of claim 20, wherein when the monitored directional correlation indicates over a further period of time a negative correlation between values corresponding to a deviation from the grid frequency and a wind power change, adjusting the output power response over said further period of time in accordance with a second control strategy.

22. The method of claim 21, wherein the first control strategy comprises transitioning the output power at a first rate of change, and wherein the second control strategy comprises transitioning the output power at a second rate of change, wherein the second rate change is higher relative to the first rate of change.

23. The method of claim 22, wherein said first rate of change comprises ramping up or ramping down the output power at a rate of 50% or less per minute with respect to a rated output power of the wind turbine.

24. The method of claim 22, wherein said second rate of change comprises transitioning the output power at an average rate of 1% or more per second with respect to a rated output power of the wind turbine.

25. The method of claim 20, wherein the first control strategy comprises delaying a transition of the output power.

26. The method of claim 20, wherein the first control strategy comprises transitioning during a transition segment the output power at a first rate of change and further comprises delaying during a delay segment the output power by a predefined time delay.