# US 7,746,080 B2 · System and method for determining a position of a single phase fault to ground in a feeder line

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- Number: US 7,746,080 B2
- Document ID: US7746080B2
- Status: Granted
- Kind: B2
- Application number: 12/059,175
- Filed: 2008-03-31
- Published: 2009-10-01
- Granted: 2010-06-29
- Earliest claimed: 2008-03-31
- Assignees: Consolidated Edison Company of New York, Inc.
- Inventors: Christopher G Jones
- Web page: https://patentgrep.com/patent/US7746080B2

## CPC

- G01R 31/088: {Aspects of digital computing}
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

A system and a method for determining a position of a single phase fault to ground in a feeder line are provided. The feeder line is electrically connected to an electrical substation via a substation bus. The system includes first and second sensors electrically coupled to a transformer in the electrical substation. The system further includes a processor that determines a reactance value based on measured electrical characteristics and a predetermined constant. The processor accesses a table having a plurality of position identifiers associated with positions on the feeder line, and a plurality of reactance component values corresponding to positions on the feeder line relative to the substation bus. The processor selects a first reactance component value from the plurality of reactance component values in the table to determine the position of a fault.

## Claims

### Claim 1

A method for determining a position of a single phase fault to ground in a feeder line, the feeder line electrically connected to an electrical substation via a substation bus, the method comprising:
measuring an amplitude and a phase angle of an electrical current being output by a transformer in the electrical substation to the substation bus electrically connected to the feeder line, utilizing a first sensor;
measuring an amplitude and a phase angle of a voltage being output by the transformer in the electrical substation to the substation bus electrically connected to the feeder line, utilizing a second sensor;
determining a reactance value based on the amplitude of the electrical current, the amplitude of the voltage, a phase angle between the electrical current and the voltage, and a predetermined constant, utilizing a processor;
accessing a table having a plurality of position identifiers associated with positions on the feeder line, and a plurality of reactance component values corresponding to reactance components of Thevenin impedances at the positions on the feeder line relative to the substation bus, utilizing the processor;
selecting a first reactance component value from the plurality of reactance component values in the table that substantially corresponds to the reactance value, utilizing the processor;
selecting a first position identifier from the plurality of position identifiers that is associated with the first reactance component value, utilizing the processor, the first position identifier indicating a first estimated position of the single phase fault to ground in the feeder line; and
displaying the first position identifier on a display device, utilizing the processor.

### Claim 2 (depends on 1)

The method of claim 1, further comprising storing the first position identifier in a memory device, utilizing the processor.

### Claim 3 (depends on 1)

The method claim 1, further comprising:
selecting a second reactance component value from the plurality of reactance component values in the table that substantially corresponds to the reactance value, utilizing the processor;
selecting a second position identifier from the plurality of position identifiers that is associated with the second reactance component value, utilizing the processor, the second position identifier indicating a second estimated position of the single phase fault to ground in the feeder line; and
displaying the second position identifier on the display device, utilizing the processor.

### Claim 4

A system for determining a position of a single phase fault to ground in a feeder line, the feeder line electrically connected to an electrical substation via a substation bus, the system comprising:
a first sensor electrically coupled to a transformer in the electrical substation, the first sensor measuring an amplitude and a phase angle of an electrical current being output by the transformer to the substation bus electrically connected to the feeder line;
a second sensor electrically coupled to the transformer in the electrical substation, the second sensor measuring an amplitude and a phase angle of a voltage being output by the transformer to the substation bus electrically connected to the feeder line; and
a processor operably communicating with the first and second sensors, the processor configured to determine a reactance value based on the amplitude of the electrical current, the amplitude of the voltage, a phase angle between the electrical current and the voltage, and a predetermined constant, the processor further configured to access a table having a plurality of position identifiers associated with positions on the feeder line, and a plurality of reactance component values corresponding to reactance components of Thevenin impedances at the positions on the feeder line relative to the substation bus, the processor further configured to select a first reactance component value from the plurality of reactance component values in the table that substantially corresponds to the reactance value, the processor further configured to select a first position identifier from the plurality of position identifiers that is associated with the first reactance component value, the first position identifier indicating a first estimated position of the single phase fault to ground in the feeder line, the processor further configured to display the first position identifier on a display device.

### Claim 5 (depends on 4)

The system of claim 4, wherein the processor is further configured to store the first position identifier in a memory device.

### Claim 6 (depends on 4)

The system of claim 4, wherein the processor is further configured to select a second reactance component value from the plurality of reactance component values in the table that substantially corresponds to the reactance value, the processor further configured to select a second position identifier from the plurality of position identifiers that is associated with the second reactance component value, the second position identifier indicating a second estimated position of the single phase fault to ground in the feeder line, the processor further configured to display the second position identifier on the display device.