Systems and methods for use in identifying and responding to type of grid fault event

Patent metadata

Field	Value
Publication number	US-9843182-B2
Application number	US-201114354336-A
Country	US
Kind code	B2
Filing date	Oct 28, 2011
Priority date	Oct 28, 2011
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

Systems ( 100 ), power modules ( 108 ), and methods for using in controlling a converter ( 110 ) coupled between a power generator ( 104 ) and an electric grid ( 102 ). A power module ( 108 ) includes the converter ( 110 ) configured to supply the output from the power generator ( 104 ) to the electric grid ( 102 ) and a controller ( 112 ) coupled to the converter ( 110 ) and configured to disable the converter ( 110 ) in response to a grid fault event, to identify the type or the grid fault event after a first predetermined interval from disabling the converter ( 110 ), and to enable switching of the converter ( 110 ), when the type of the grid fault event is identified as a low voltage condition.

First claim

What is claimed is:

1. A power module for use in controlling a converter coupled between a power generator and an electric grid, said power module comprising:
a converter configured to supply an output from a power generator to an electric grid; and,
a controller coupled to said converter and configured to:
disable said converter in response to a grid fault event, such that said converter is gated off;
identify the type of grid fault event after a first predetermined interval from disabling said converter; and
enable said entire converter, when the type of the grid fault event is identified as a low voltage condition.

2. The power module of claim 1 , wherein said controller is configured to identify the type of the grid fault event based on the voltage associated with the electric grid after the first predetermined interval.

3. The power module of claim 2 , wherein said controller is configured to determine if a phase-lock-loop (PLL) module of said controller is locked on the electric grid after a second predetermined interval, when the type of the grid fault event is identified by said controller as a phase jump condition.

4. The power module of claim 3 , wherein the second predetermined interval is within the range between about 10 milliseconds and about 120 milliseconds.

5. The power module of claim 1 , wherein said controller is configured to enable said converter to output reactive current to the electric grid, when the type of the grid fault event is identified by said controller as a low voltage condition.

6. The power module of claim 1 , wherein the first predetermined interval is within the range between about 2 milliseconds and about 20 milliseconds.

7. The power module of claim 1 , wherein said controller is configured to detect the grid fault event based on an amplitude and/or a phase frequency of a voltage measured at one of said converter and the electric grid.

8. The power module of claim 1 , wherein said power module is configured to trip when the type of the grid fault event is identified as a phase jump condition and the grid fault event persists for at least about 1.0 second after identified as a phase jump condition.

9. A power system comprising:
a power generator configured to generate a DC voltage; and,
a power module coupled to said power generator and configured to convert the DC output to an AC output and provide the AC output to an electric grid, said power module including a converter, said power module is configured to:
detect a grid fault event based on a parameter associated with said converter;
disable said converter in response to the detected grid fault event, such that said converter is gated off;
identify a type of the grid fault event after a first predetermined interval based on the parameter associated with said converter;
when the type of the grid fault event is identified as a phase jump condition, determine if a phase-lock-loop (PLL) module is locked onto the electric grid after a second predetermined interval; and
enable said entire converter, after the second predetermined interval, when the type of the grid fault event is identified as a phase jump condition.

10. The power system of claim 9 , wherein the parameter associated with said converter comprises a voltage associated with said converter.

11. The power system of claim 10 , wherein said power module is further configured to enable switching of said converter, when the type of grid fault event is identified by said controller as a low voltage condition, to supply reactive current to the electric grid.

12. The power system of claim 9 , wherein the power generator comprises at least one photovoltaic array.

13. The power system of claim 9 , wherein said power module comprises a DC-DC converter coupled between said power generator and said converter, said DC-DC converter configured to boost the DC voltage supplied from said power generator.

14. A method for use by a power module in controlling a converter coupled between a power generator and an electric grid, the power module including a converter and a controller coupled to the converter, said method comprising:
detecting a grid fault event as a function of a parameter associated with the electric grid;
disabling the converter based on the detected grid fault event, such that the converter is gated off;
identifying, at the controller, the type of the grid fault event after waiting a first predetermined interval; and
enabling said entire converter, when the type of the grid fault event is identified as a low voltage condition.

15. The method of claim 14 , wherein the parameter associated with the electric grid comprises a voltage associated with the converter.

16. The method of claim 15 , wherein identifying the type of grid fault event includes measuring a magnitude of the voltage associated with the converter.

17. The method of claim 15 , further comprising enabling the converter, when the identified type of the grid fault event is a low voltage condition, to supply reactive power to the electric grid.

18. The method of claim 17 , wherein the first predetermined interval is within the range between about 2.0 millisecond and about 20.0 milliseconds.

19. The method of claim 15 , further comprising determining if a phase-lock-loop (PLL) module of the power module is locked on the voltage associated with the converter after a second predetermined interval, when the identified type of grid fault event is a phase jump condition.

20. The method of claim 19 , wherein the second predetermined interval is within the range between about 10 milliseconds and about 120 milliseconds.

21. The method of claim 19 , further comprising tripping the power module when the PLL module is not lock onto the voltage associated with the converter after at least about 1.0 second from identifying the type of the grid fault event.

Assignees

• Zhu Huibin
• Smith David
• Gong Maozhong
• Wu Xeuqin
• Gen Electric

Inventors

• Zhu Huibin
• Smith David
• Gong Maozhong
• Wu Xeuqin

Classifications

• H02J3/381

  Dispersed generators · CPC title

• H02J2101/24

  Photovoltaics · CPC title

• Y02E70/30

  Systems combining energy storage with energy generation of non-fossil origin · CPC title

• G01R19/2513

  Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging · CPC title

• H02J3/28

  Arrangements for balancing of the load in networks by storage of energy · CPC title