Fault detection and location in nested microgrids

Patent metadata

Field	Value
Publication number	US-10483754-B2
Application number	US-201715655378-A
Country	US
Kind code	B2
Filing date	Jul 20, 2017
Priority date	May 1, 2017
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

Unique systems, methods, techniques and apparatuses of a power grid control system. One exemplary embodiment is a microgrid comprising a plurality of switching devices, a plurality of distribution line segments, a plurality of measuring devices, each measuring device corresponding to one of the plurality of switching devices, and a network controller. The network controller is configured to: receive measurements from the plurality of measurement devices, determine a fault is occurring within the microgrid using the measurements, assign a topology classification to each of the plurality of distribution line segments, assign a proximity classification to each of the plurality of distribution line segments, determine fault location using the topology classification and the proximity classification, and isolate the fault by transmitting open commands to the two switching devices of the plurality of switching devices closest to the fault.

First claim

What is claimed is:

1. A microgrid comprising:
a plurality of switching devices;
a plurality of distribution line segments, each distribution line segment coupled to at least one switching device of the plurality of switching devices;
a plurality of measuring devices, each measuring device corresponding to one of the plurality of switching devices; and
at least one distributed energy resource (DER) coupled to one of the plurality of distribution line segments;
a network controller configured to:
receive measurements from the plurality of measurement devices,
determine a fault is occurring within the microgrid using the measurements,
assign a topology classification to each of the plurality of distribution line segments based on whether a load or a DER is coupled to the distribution line segment following the determining a fault is occurring,
assign a proximity classification to said each of the plurality of distribution line segments based on whether a fault current may flow through the distribution line segment in one direction or two directions following the determining a fault is occurring,
determine fault location using the topology classification and the proximity classification, and
isolate the fault by transmitting open commands at least one of the plurality of switching devices closest to the fault.

2. The microgrid of claim 1 wherein each of the plurality of measuring devices comprises a directional fault indicator.

3. The microgrid of claim 1 wherein each of the plurality of measuring devices is incorporated into a corresponding switch of the plurality of switching devices.

4. The microgrid of claim 1 wherein the network controller is configured to receive measurements including an open/close switch status for each of the plurality of switching devices.

5. The microgrid of claim 1 wherein the network controller is configured to assign a topological classification by determining an operational status of each DER coupled to the distribution line.

6. The microgrid of claim 1 wherein the network controller is configured to classify each of the plurality of distribution line segments based on whether a load or a DER is coupled to the distribution line segment includes classifying a line segment as having neither a coupled load nor a coupled DER.

7. The microgrid of claim 1 wherein the network controller determines the location of the fault within a line segment with a proximity classification indicating fault current may flow into the line segment from two directions by determining fault current is flowing into the line segment in two directions.

8. The microgrid of claim 1 wherein the network controller assigns a topological classification to one distribution line segment of the plurality of distribution line segments indicating a DER is coupled to the distribution line segment and the distribution line segment is only coupled to one distribution line segment by way of one switching device of the plurality of switching devices, and wherein the network controller isolates the fault by opening the one switching device in response to determining current is flowing into the one line segment of the plurality of line segments.

9. The microgrid of claim 1 wherein the network controller determines the proximity classifications of a portion of the plurality of distribution line segments indicate fault current may flow through the portion of the plurality of distribution line segments in one direction, determines one topology classification of the portion of the plurality of distribution line segments indicates a DER is coupled to one of the distribution lines segments of the portion, and opens the switching device between the distribution line segment coupled to the DER and the remaining distribution line segments of the portion of the plurality of distribution line segments.

10. The microgrid of claim 9 wherein the network controller is configured to receive measurements from a portion of the plurality of switching devices corresponding to a power output of the DER coupled to the one of the distribution lines segments of the portion, and close the switching device between the distribution line segment coupled to the DER and the remaining distribution line segments of the portion of the plurality of distribution line segments in response to determining a voltage or power frequency of the power output of the DER is not collapsing.

11. The microgrid of claim 1 wherein the network controller determines the proximity classifications of a portion of the plurality of distribution line segments indicates fault current may flow through the portion of plurality of distribution line segments in one direction, determines one topology classification of the portion of the plurality of distribution line segments indicates a DER is coupled to one of the distribution lines segments of the portion, and opens the switching device between the distribution line segment coupled to the DER and the remaining distribution line segments of the portion of the plurality of distribution line segments.

12. A method for detecting and isolating a fault condition in a microgrid comprising:
operating a plurality of switching devices coupled between a plurality of line segments with a network controller;
receiving measurements from the plurality of switching devices with the network controller;
determining a fault is occurring within the microgrid using the measurements with the network controller;
assigning a topology classification to each of the plurality of line segments based on whether a load or a distributed energy resource (DER) is coupled to the line segment;
assigning a proximity classification to said each of the plurality of line segments based on whether a fault current may flow through the line segment in one direction or two directions;
determining the location of the fault condition using the topology classifications and the proximity classifications of the plurality of line segments; and
isolating the location of the fault in response to determining the location of the fault condition with a portion of the plurality of switching devices.

13. The method of claim 12 wherein determining the location of the fault condition includes:
identifying each line segment with a two direction current proximate classification;
determining whether current is entering the line segment in two directions; and
identifying the location of the fault condition in response to determining current is entering the line segment in two directions.

14. The method of claim 13 wherein determining the location of the fault condition includes:
identifying each line segment with a one direction current proximate classification, a DER topology classification, coupled to only one of the plurality of switching devices;
determining whether current is entering the line segment; and
identifying the location of the fault condition in response to determining current is entering the line segment.

15. The method of claim 14 wherein determining the location of the fault condition includes:
identifying each line segment with a one direction current proximate classification and coupled to at least two of the plurality of switching devices, and determining whether one of the line segments has a DER topology classification; and
wherein isolating the location of the fault includes opening the switching device coupled to the DER topology classification through which current is flowing into the segment.

16. The method of claim 15 wherein determining the location of the fault condition includes identifying each group of two line

Assignees

• Abb Schweiz Ag

Inventors

• Hong Junho
• Kondabathini Anil
• Ishchenko Dmitry

Classifications

• H02J3/38

  Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel · CPC title

• H02J3/0073

  by providing alternative feeding paths when the main path fails · CPC title

• H02J2101/20

  Dispersed power generation using renewable energy sources · CPC title

• H02H7/261

  involving signal transmission between at least two stations (transmission of signals in general H02H1/0061) · CPC title

• H02J2105/12

  supplying households or buildings · CPC title