Claims
- 1. A wind farm comprising:
a plurality of wind turbines each of which produces multi-phase alternating current electrical output with a wave form consisting of a fundamental component and harmonics thereof; a device at one said wind turbine for modifying the output thereof; and an electrical collection system that aggregates the outputs of said plurality of wind turbines wherein one or more of the harmonic components of the outputs of said wind turbines are substantially canceled in said collection system.
- 2. The wind farm of claim 1 wherein said device for modifying the output of one II said wind turbine is a transformer.
- 3. The wind farm of claim 2 wherein said transformer provides a phase shift in the voltage wave form of said wind turbine.
- 4. The wind farm of claim 3 wherein said transformer is a zig-zag wound transformer.
- 5. The wind farm of claim 3 wherein said transformer is a wye-delta transformer.
- 6. The wind farm of claim 2 wherein said transformer is an extended delta transformer.
- 7. The wind farm of claim 1 wherein each of said wind turbines is a variable speed wind turbine.
- 8. The wind farm of claim 7 wherein each of said wind turbines comprises a multiphase generator that produces electrical output with varying frequency, a power converter for converting said varying frequency electrical power into constant frequency power with a low pulse number.
- 9. The wind farm of claim 8 wherein each of said wind turbines further comprises a turbine transformer and wherein the turbine transformer of at least one wind turbine shifts the phase of the voltage wave form of the output of said at least one wind turbine relative to the output of the other wind turbines.
- 10. The wind farm of claim 9 wherein said turbine transformer at said wind turbines perform phase multiplication on the output of said power converters to create a high pulse number approximation of a sine wave at an interconnection point with a utility grid.
- 11. The wind farm of claim 10 wherein each said transformer is a zig-zag wound transformer.
- 12. The wind farm of claim 11 wherein said zig-zag transformers provide a phase shift in the voltage wave form that varies between wind turbines thereby to substantially cancel harmonic content in the output of said wind turbines.
- 13. The wind farm of claim 1 wherein at least the 5th and 7th harmonics of the outputs of said wind turbines are canceled in said electrical collection system.
- 14. A wind farm comprising:
a plurality of wind turbines each of which produces multi-phase alternating current electrical output with a wave form that has a first distortion; a device for modifying the output of at least one wind turbine; and an electrical collection system that aggregates the outputs of said plurality of wind turbines to create a net wind farm output with a distortion that is lower than said first distortion.
- 15. The wind farm of claim 14 wherein the output of each said wind turbine does not comply with the harmonic requirements of IEEE 519 and wherein said net output does comply with the harmonic requirements of IEEE 519.
- 16. The wind farm of claim 14 wherein said device for modifying the output of at least one wind turbine is a multi-phase transformer.
- 17. The wind farm of claim 16 wherein said transformer provides a phase shift in the voltage wave form of said at least one wind turbine between the primary and secondary sides of said transformer.
- 18. The wind farm of claim 17 wherein said transformer is a zig-zag wound transformer.
- 19. The wind farm of claim 18 wherein said transformer is a wye-delta transformer.
- 20. The wind farm of claim 19 wherein said transformer is and extended delta transformer.
- 21. The wind farm of 16 wherein said transformer provides phase multiplication.
- 22. The wind farm of claim 16 wherein said transformer comprises more than one winding segment for each phase on either the primary or the secondary side of the transformer.
- 23. The wind farm of claim 14 wherein each said wind turbine comprises a DC portion of the electrical power circuit thereof and further comprises a six pulse inverter for converting DC power to alternating current power.
- 24. The wind farm of claim 23 wherein said six pulse inverter comprises line commutated SCRs.
- 25. A wind farm comprising:
a plurality of wind turbines; an electrical network coupling said wind turbines to a utility grid at a connection point; and a static active VAR source that provides harmonic cancellation currents to reduce the harmonic content in the electrical output of said wind farm.
- 26. The wind farm of claim 25 wherein said static active VAR source is located at said utility grid connection point.
- 27. The wind farm of claim 25 wherein said static active VAR source is embedded within said wind farm at a location remote from said utility grid interconnection point.
- 28. The wind farm of claim 25 wherein said static active VAR source comprises solid state switching devices.
- 29. The wind farm of claim 28 wherein said wind farm further comprises a switchable bank of capacitors.
- 30. A wind farm comprising:
a plurality of wind turbines each of which produces multi-phase alternating current electrical output wherein each said wind turbine comprises two six pulse inverters and wherein the outputs of said two six pulse inverters are combined to provide a twelve pulse alternating current electrical output.
- 31. The wind farm of claim 30 wherein the outputs of said two six pulse inverters are combined in a transformer associated with a respective said wind turbine.
- 32. The wind farm of claim 31 wherein each said transformer has two low voltage windings wherein one said low voltage winding is a wye winding and one said low voltage winding is a delta winding.
- 33. The wind farm of claim 32 wherein the high voltage side of at least two of said transformers have different winding configurations from each other.
- 34. The wind farm of claim 33 wherein the high voltage side of at least two of said transformers have winding configurations that provide a phase shift in the voltage wave form of the electrical output of their respective wind turbines relative to each other.
- 35. The wind farm of claim 30 further comprising harmonic cancellation located at an interconnection point between said wind farm and a utility grid.
- 36. The wind farm of claim 35 wherein said harmonic cancellation comprises a static active VAR source that provides harmonic cancellation currents to reduce the harmonic content in the electrical output of said wind farm.
- 37. A wind farm comprising:
a plurality of wind turbines each of which produces multiphase alternating current electrical output with low pulse number; a transformer associated with at least one said wind turbine that shifts the phase of the current output of said wind turbine by a predetermined phase shift angle; and an electrical collection system that aggregates the outputs of said plurality of wind turbines wherein a high pulse number electrical output is created at a point of interconnection with a utility grid.
- 38. A wind farm comprising:
a group of at least two wind turbines each of which produces multiphase alternating current electrical output wherein each of said at least two wind turbines in said group has a unique transformer configuration wherein phase multiplication results from combining the current outputs of said at least two wind turbines in said group.
- 39. The wind farm of claim 38 wherein the current output of each of said at least two wind turbines comprises a low pulse number wave form and wherein the combined current output of said at least two wind turbines in said group comprises a high pulse number wave form.
- 40. The wind farm of claim 38 wherein the output of each of said at least two wind turbines comprises a current wave form with a first distortion and wherein the combined current output of said at least two wind turbines in said group comprises a current wave form with a distortion lower than said first distortion. 41. The wind farm of claim 38 wherein the output of each of said at least two wind turbines does not meet the harmonics requirements of IEEE 519 and wherein the combined output of said at least two wind turbines in said group does meet the harmonics requirements of IEEE 519.
RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 60/386,442 which was filed on Jun. 7, 2002 and which is incorporated herein by reference.
Provisional Applications (1)
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Number |
Date |
Country |
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60386442 |
Jun 2002 |
US |