Determining reactive power capability of a renewable energy system

Patent metadata

Field	Value
Publication number	US-2016237990-A1
Application number	US-201514624906-A
Country	US
Kind code	A1
Filing date	Feb 18, 2015
Priority date	Feb 18, 2015
Publication date	Aug 18, 2016
Grant date	—

Abstract

Systems and methods for controlling a renewable energy system based on actual reactive power capability of the renewable energy system are provided. The reactive power output of the renewable energy system can be controlled based at least in part on an initial reactive power limit. The initial reactive power limit can be determined based on rated reactive power for the power generation units in the renewable energy system. When a difference between a reactive power demand and the actual reactive power production of the renewable energy system fall outside a threshold, the initial reactive power limit can be adjusted to a corrected reactive power limit that is closer to the actual reactive power capability of the renewable energy system.

First claim

1 . A method for controlling a renewable energy system, comprising:
controlling, by one or more control devices, a reactive power output for a renewable energy system based at least in part on an initial reactive power limit for the renewable energy system; determining, by the one or more control devices, a difference between a reactive power demand and an actual reactive power production for the renewable energy system; wherein when the difference falls outside a threshold, the method comprises:
determining, by the one or more control devices, a correction factor for the initial reactive power limit;
adjusting, by the one or more control devices, the initial reactive power limit to a corrected reactive power limit based at least in part on the correction factor; and
controlling, by the one or more control devices, the reactive power output for the renewable energy system based at least in part on the corrected reactive power limit;
detecting, by the one or more control devices, the difference returning to within the threshold; and in response to detecting the difference returning to within the threshold, controlling, by the one or more control devices, the reactive power output based at least in part on the initial reactive power limit.

2 . (canceled)

3 . The method of claim 1 , wherein the initial reactive power limit is determined by aggregating a rated reactive power for each of a plurality of power generation units in the renewable energy system.

4 . The method of claim 1 , wherein the correction factor results in adjusting the initial reactive power limit towards the actual reactive power capability of the renewable energy system.

5 . The method of claim 1 , wherein the initial reactive power limit comprises an initial maximum reactive power limit and an initial minimum reactive power limit.

6 . The method of claim 5 , wherein the corrected reactive power limit comprises a corrected maximum reactive power limit and a corrected minimum reactive power limit.

7 . The method of claim 1 , wherein the threshold comprises 5% of rated reactive power for the renewable energy system.

8 . The method of claim 1 , wherein the corrected reactive power limit is used to limit a reactive power command for the renewable energy system.

9 . The method of claim 8 , wherein the reactive power command is distributed to a plurality of power generation units.

10 . A control system for controlling a renewable energy system, the control system comprising:
a voltage regulator implemented by one or more control devices, the voltage regulator configured to provide a reactive power command based at least in part on a voltage error signal; a limiter implemented by the one or more control devices, the limiter configured to limit the reactive power command based at least in part on an initial reactive power limit for the renewable energy system; a reactive power limit correction module implemented by the one or more control devices, the reactive power limit correction module configured to adjust the initial reactive power limit to a corrected reactive power limit when a difference between the reactive power command for the renewable energy system and an actual reactive power production for the renewable energy system falls outside of a threshold, and wherein the reactive power limit correction module is configured to detect the difference returning to within the threshold, and in response to detecting the difference returning to within the threshold, control the reactive power output based at least in part on the initial reactive power limit; wherein the corrected reactive power limit corrects the initial reactive power limit towards the actual reactive power capability of the renewable energy system.

11 . The control system of claim 10 , the initial reactive power limit is determined by aggregating a rated reactive power for each of a plurality of power generation units in the renewable energy system.

12 . The control system of claim 10 , wherein the threshold comprises 5% of rated reactive power for the renewable energy system.

13 . The control system of claim 10 , wherein the corrected reactive power limit is determined based at least in part on a correction factor, the correction factor determined based on the difference between the reactive power demand for the renewable energy system and the actual reactive power production for the renewable energy system.

14 . The control system of claim 10 , wherein the reactive power command is determined based at least in part on a power factor setpoint for the renewable energy system.

15 . A wind farm, comprising:
a plurality of wind turbines; a plurality of wind turbine controllers, each wind turbine controller associated with at least one of the plurality of wind turbines; and a wind farm controller, the wind farm controller in communication with each of the wind turbine controllers, the wind farm controller configured to adjust an initial reactive power limit to a corrected reactive power limit based at least in part on a difference between a reactive power demand for the wind farm and an actual reactive power production for the wind farm, the wind farm controller further configured to control the reactive power output for the wind farm based on the corrected reactive power limit, and wherein the wind farm controller is configured to detect the difference returning to within a threshold, and in response to detecting the difference returning to within the threshold, control the reactive power output based at least in part on the initial reactive power limit; wherein the initial reactive power limit is determined by aggregating a rated reactive power for each of a plurality of wind turbines in the wind farm and the corrected reactive power limit adjusts the initial reactive power limit toward an actual reactive power capability of the wind farm.

16 . The wind farm of claim 15 , wherein the wind farm controller is configured to adjust an initial reactive power limit to a corrected reactive power limit based at least in part on a difference between a reactive power demand for the wind farm and an actual reactive power production for the wind farm by determining that the difference falls outside the threshold and adjusting the initial reactive power limit to the corrected reactive power limit when the difference falls outside the threshold.

17 . The wind farm of claim 16 , wherein the initial reactive power limit is adjusted to the corrected reactive power limit based at least in part on a correction factor, the correction factor determined based on the difference between the reactive power demand and the actual reactive power production.

18 . The wind farm of claim 16 , wherein the threshold is 5% of rated reactive power for the wind farm.

19 . The wind farm of claim 15 , wherein the wind farm controller is configured to distribute the reactive power command among the plurality of wind turbine controllers.

20 . The wind farm of claim 15 , wherein the wind farm controller is configured to control the reactive power output of the wind farm based at least in part on a power factor setpoint.

Assignees

• Gen Electric

Inventors

• Ubben Enno
• Barton Werner Gerhard
• Junge Carsten
• Smolenski Arnim

Classifications

• H02J2101/28

  Wind energy · CPC title

• H02J2101/20

  Dispersed power generation using renewable energy sources · CPC title

• F03D7/0284

  in relation to the state of the electric grid · CPC title

• H02J3/1885

  using rotating AC generators, e.g. synchronous generators · CPC title

• H02J3/18

  Arrangements for adjusting, eliminating or compensating reactive power in networks · CPC title