Utilization of distributed generator inverters as statcom

Patent metadata

Field	Value
Publication number	US-2016197482-A1
Application number	US-201615072014-A
Country	US
Kind code	A1
Filing date	Mar 16, 2016
Priority date	Sep 15, 2009
Publication date	Jul 7, 2016
Grant date	—

Abstract

The invention provides a method and system for operating a solar farm inverter as a Flexible AC Transmission System (FACTS) device—a STATCOM—for voltage control. The solar farm inverter can provide voltage regulation, damping enhancement, stability improvement and other benefits provided by FACTS devices. In one embodiment, the solar farm operating as a STATCOM at night is employed to increase the connectivity of neighbouring wind farms that produce peak power at night due to high winds, but are unable to connect due to voltage regulation issues. The present invention can also operate during the day because there remains inverter capacity after real power export by the solar farm. Additional auxiliary controllers are incorporated in the solar farm inverter to enhance damping and stability, and provide other benefits provided by FACTS devices.

First claim

What is claimed is:

1 . A distributed power generation source for operatively connecting to a power grid system at a point of common coupling, said distributed power generation source comprising:
a voltage inverter; and a controller that operates said voltage inverter as a static synchronous compensator (STATCOM) when said distributed power generation source is providing less than a maximum rated active power of said distributed power generation source to said power grid system;
wherein
a voltage at said point of common coupling is regulated by said controller,
said STATCOM prevents said voltage at said point of common coupling from exceeding a specified voltage range when at least one additional distributed power generation source is operatively connected to said power grid system,
said STATCOM produces an excess amount of power relative to an amount of power required by at least one load on said distributed power generation network.

2 . The distributed power generation source according to claim 1 , wherein said inverter is operated as said STATCOM when said distributed power generation source is not providing active power to said power grid system.

3 . The distributed power generation source according to claim 1 , wherein said distributed power generation source is a solar farm.

4 . The distributed power generation source according to claim 1 , wherein said distributed power generation source is a solar farm and said inverter is operated as said STATCOM when said solar farm is not generating active power.

5 . The distributed power generation source according to claim 1 , wherein said distributed power generation source is an inverter based wind farm.

6 . The distributed power generation source according to claim 1 , wherein said distributed power generation source is an inverter based wind farm and said inverter is operated as said STATCOM when said wind farm is not generating active power.

7 . The distributed power generation source according to claim 1 , wherein at least one of said at least one additional distributed power generation source is a wind farm.

8 . The distributed power generation source according to claim 1 , wherein said distributed power generation source and said at least one additional distributed power generation source are electrically connected to said power grid system.

9 . A control system for use in controlling a distributed generation (DG) power source, said control system having at least one specific function relating to a power grid system, wherein at least one input of the control system is derived from a characteristic of a signal passing through said power grid system.

10 . The control system according to claim 9 , wherein said at least one specific function of said DG power source is at least one of:
a voltage regulation of a point of common coupling (PCC) voltage and a damping control, the voltage regulation being constructed and arranged to control transient signals on said power transmission system through dynamic reactive power control; a DC bus voltage regulation; and an active power injection into said power grid system.

11 . The control system according to claim 9 , wherein at least one of said plurality of inputs received by said control system is at least one of:
a PCC voltage, a line current, a line power flow, a bus frequency, rotor oscillations of generators in power grid, and inter area oscillations, and
wherein said at least one of said plurality of inputs is at least one of: measured, computed and communicated.

12 . A system for improving stability of a power grid system, said system comprising:
a power generating source having an output being injected on to said power grid system; a damping controller receiving as input a signal indicative of oscillations in said power grid system, and said damping controller outputting a damping control signal; and a control system receiving said damping control signal, wherein said control system outputs a control signal proportional to a transient signal on said power grid system; wherein said control signal controls said power generating source such that said output is based on said control signal; wherein said control system operates said voltage inverter of said power generating source as a Static Synchronous Compensator (STATCOM) to exchange controlled reactive power to improve said stability of said power grid system; wherein said control system operates said voltage inverter as a STATCOM only when said voltage inverter is operating at a capacity less than a rated capacity of said voltage inverter; said control system operating said voltage inverter as a STATCOM using an unutilized capacity of said voltage inverter, and wherein said damping controller comprises a compensator for compensating for said oscillations of said power grid system.

13 . The system according to claim 12 , wherein said power generating source is a solar farm DG power source.

14 . The system according to claim 12 , wherein said power generating source is a wind farm DG power source.

Assignees

• Univ Western Ontario

Inventors

• Varma Rajiv Kumar
• Khadkikar Vinod
• Rahman Shah Arifur

Classifications

• H02J3/01 Primary

  Arrangements for reducing harmonics or ripples · CPC title

• H02J3/1842

  having reactive elements actively controlled by bridge converters, e.g. active filters or static compensators [STATCOM] · CPC title

• H02J3/381

  Dispersed generators · CPC title

• H02J3/40

  Synchronisation of generators for connection to a network or to another generator · CPC title

• Y02E40/40

  Arrangements for reducing harmonics · CPC title