System and method for voltage control of wind generators

Patent metadata

Field	Value
Publication number	US-9318988-B2
Application number	US-201314018482-A
Country	US
Kind code	B2
Filing date	Sep 5, 2013
Priority date	Sep 5, 2013
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

A system and associated method for reactive power generation for a wind turbine generator includes receiving a higher-than-generator level voltage command signal. A reactive current is determined for the wind turbine generator in response to the voltage command signal and is transmitted to a controller of the wind turbine generator for generating a real and reactive power based on the reactive current command. A trim value may be generated and applied to the voltage command signal.

First claim

What is claimed is:

1. A method for reactive power generation for a wind turbine generator within a wind farm, comprising:
receiving, from a field-level controller, a field-level voltage command signal, the field-level voltage command determined as a function of a power output of the wind farm and a voltage at a point of common coupling of a plurality of wind turbine generators;
determining a generator-level voltage command for the wind turbine generator by adjusting the field-level voltage command signal as a function of a local reactive power droop characteristic for the wind turbine generator;
determining a reactive current command for the wind turbine generator in response to the generator-level voltage command;
transmitting the reactive current command to a controller of the wind turbine generator; and
generating, via the controller of the wind turbine generator, a reactive power of the wind turbine generator based on the reactive current command that is determined in response to the field-level voltage command signal.

2. The method as in claim 1 , wherein the generator-level voltage command signal is limited to a range of upper and lower limits based on generator terminal voltage, and the reactive current command is limited to a range based on a current rating of the wind turbine generator.

3. The method as in claim 2 , wherein the generator-level voltage command signal is compared to a measured terminal voltage of the wind turbine generator to generate an error voltage signal transmitted to a voltage regulator.

4. The method as in claim 1 , wherein the field-level voltage command signal is applicable to all or a subset of wind turbines within the wind farm.

5. The method as in claim 1 , wherein the droop characteristic is preset and varies for different wind turbine generators within the wind farm or substation.

6. The method as in claim 1 , comprising generating a voltage trim signal as a function of the reactive power droop characteristic and a measured reactive power feedback signal from the wind turbine generator, and applying the voltage trim signal to the field-level voltage command signal to generate the generator-level voltage command signal.

7. The method as in claim 1 , further comprising adjusting the field-level voltage command signal as a function of a real power offset value for the wind turbine.

8. The method as in claim 7 , wherein the real power offset value is preset and varies for different wind turbine generators within wind farm or substation.

9. The method as in claim 7 , comprising generating a voltage trim signal as a function of the real power offset value and a measured real power feedback signal from the wind turbine generator, and applying the voltage trim signal to the field-level voltage command signal to generate the generator-level voltage command signal.

10. The method as in claim 1 , further comprising adjusting the field-level voltage command signal as a combined function of a local reactive power droop characteristic and real power offset value for the wind turbine generator.

11. The method as in claim 10 , wherein either or both of the droop characteristic and real power offset value varies for different wind turbine generators within the wind farm or substation.

12. The method as in claim 10 , comprising generating a voltage trim signal as a function of the combination of the reactive power droop characteristic applied to a measured reactive power feedback signal for the wind turbine generator, and the real power offset value applied to a measured real power feedback signal for the wind turbine generator, and applying the voltage trim signal to the field-level voltage command signal to generate the generator-level voltage command signal.

13. A method for reactive power generation for a wind turbine generator, within a wind farm, comprising:
receiving a field-level voltage command for a wind turbine generator from a field-level controller, the field-level voltage command determined as a function of a power output of the wind farm and a voltage at a point of common coupling of a plurality of wind turbine generators;
receiving a feedback reactive power signal for the individual wind turbine;
applying a local reactive power droop characteristic for the wind turbine generator to the feedback reactive power signal to generate a voltage trim value;
limiting the voltage trim value to a predetermined voltage range;
applying the voltage trim value to the field-level voltage command to generate an adjusted voltage command;
limiting the adjusted voltage command to a predetermined voltage range;
generating a voltage error signal based on a measured voltage of the wind turbine generator and the adjusted voltage command;
generating a reactive current command based on the voltage error signal, and limiting the reactive current command to a predetermined current range; and
generating a reactive power of the wind turbine generator based on the reactive current command that is based on the voltage command received from the field-level controller.

14. A method for reactive power generation for a wind turbine generator, within a wind farm, comprising:
receiving a field-level voltage command for a wind turbine generator from a field-level controller, the field-level voltage command determined as a function of a power output of the wind farm and a voltage at a point of common coupling of a plurality of wind turbine generators;
receiving a feedback real power signal for the individual wind turbine;
applying a real power offset value to the feedback real power signal to generate a voltage trim value;
limiting the voltage trim value to a predetermined voltage range;
applying the voltage trim value to the field-level voltage command to generate an adjusted generator level voltage command;
limiting the adjusted generator level voltage command to a predetermined voltage range;
generating a voltage error signal based on a measured voltage of the wind turbine generator and the adjusted generator level voltage command;
generating a reactive current command based on the voltage error signal, and limiting the reactive current command to a predetermined current range; and
generating a reactive power of the wind turbine generator based on the reactive current command that is based on the field-level voltage command received from the field-level controller.

Assignees

• Gen Electric

Inventors

• Larsen Einar Vaughn
• Achilles Alfredo Sebastian

Classifications

• H02J2101/28

  Wind energy · CPC title

• F03D7/048

  controlling wind farms · CPC title

• H02P9/305

  controlling voltage (H02P9/302 takes precedence) · CPC title

• F03D9/257

  the wind motor being part of a wind farm · CPC title

• H02J3/16 Primary

  by adjustment of reactive power · CPC title