Fault location during pole-open condition

Patent metadata

Field	Value
Publication number	US-10197614-B2
Application number	US-201615143938-A
Country	US
Kind code	B2
Filing date	May 2, 2016
Priority date	May 2, 2016
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

The present disclosure illustrates the errors that are encountered when using both single-ended and double-ended normal-mode fault location calculations when a fault occurs in a pole-open condition. The disclosure provides systems and methods for accurately calculating the location of faults that occur during pole-open conditions, including single-ended approaches and double-ended approaches.

First claim

What is claimed:

1. A single-ended fault location determination system, comprising:
one or more computer-readable storage media;
a processor operatively coupled to the one or more computer-readable storage media, wherein the processor is configured to:
determine current values on at least two phase lines of a three-phase transmission system during a pole-open condition;
determine a fault current value, I AG , of a faulted loop during a fault;
determine a prefault sequence current value, IXL pref , of the three-phase transmission system during the pole-open condition;
determine a sequence fault current value, IXL, during the fault, wherein an incremental value of the sequence current, ΔIXL, corresponds to the difference between the prefault sequence current value, IXL pref , and the sequence fault current value, IXL;
determine a current distribution factor phase angle, e −jψx , based on impedance values of at least two sequence networks;
calculate a tilt value corresponding to a conjugate of a product of the incremental value of the sequence current, ΔIXL, and the current distribution factor phase angle, e −jψx ;
calculate a distance dividend corresponding to an imaginary part of a product of the voltage of the faulted loop, VAL, and the tilt value;
calculate a distance divisor corresponding to an imaginary part of a product of a positive-sequence impedance, ZL1, the fault current value, I AG , and the tilt value;
determine a distance to the fault corresponding to a quotient of the distance dividend and the distance divisor; and
provide the distance to the fault during the pole-open condition by utilizing the at least two sequence networks of the three-phase transmission system to compensate for a voltage potential across an open pole of the three-phase transmission system.

2. The system of claim 1 , wherein the prefault sequence current value, IXL pref , comprises a prefault zero-sequence current value I0L pref , and wherein the sequence fault current value, IXL, comprises a zero-sequence current value I0L, such that the incremental value of the sequence current, ΔIXL, comprises an incremental value of the zero-sequence current ΔI0L, and the current distribution factor phase angle, e −jψx , is a zero-sequence current distribution factor phase angle, e −jψ0 .

3. The system of claim 1 , wherein the prefault sequence current value, IXL pref , comprises a prefault positive-sequence current value I1L pref , and wherein the sequence fault current value, IXL, comprises a positive-sequence current value I1L, such that the incremental value of the sequence current, ΔIXL, comprises an incremental value of the positive-sequence current ΔI1L, and the current distribution factor phase angle, e −jψx , is the positive-sequence current distribution factor phase angle, e −jψ1 .

4. The system of claim 1 , wherein the prefault sequence current value, IXL pref , comprises a prefault negative-sequence current value I2L pref , and wherein the sequence fault current value, IXL, comprises a negative-sequence current value I2L, such that the incremental value of the sequence current, ΔIXL, comprises an incremental value of the negative-sequence current ΔI2L, and the current distribution factor phase angle, e −jψx , is the negative-sequence current distribution factor phase angle, e −jψ2 .

5. The system of claim 1 , wherein the current distribution factor phase angle, e −jψx , is based on impedance values of a positive-sequence network of the three-phase transmission system and a zero-sequence network of the three-phase transmission system.

6. The system of claim 1 , wherein the current distribution factor phase angle, e −jψx , is based on impedance values of a negative-sequence network of the three-phase transmission system and a zero-sequence network of the three-phase transmission system.

7. The system of claim 1 , wherein the current distribution factor phase angle, e −jψx , is based on impedance values of a negative-sequence network of the three-phase transmission system and a positive-sequence network of the three-phase transmission system.

8. The system of claim 1 , wherein the current distribution factor phase angle, e −jψx , is further made a function of the distance, d, to the fault and wherein the distance, d, is solved through an iterative polynomial curve-fitting algorithm.

9. The system of claim 1 , wherein the voltage of the faulted loop, VAL, is measured using a voltage meter.

10. A method, comprising:
determining, via at least one current sensor, a fault current value, I AG , of a faulted loop during a fault;
calculating a prefault sequence current value, IXL pref , of a three-phase transmission system during a pole-open condition, and
calculating a sequence fault current value, IXL, during a fault,
calculating an incremental value of the sequence current, ΔIXL, corresponding to the difference between the prefault sequence current value, IXL pref , and the sequence fault current value, IXL;
identifying a current distribution factor phase angle, e −jψx , based on impedance values of at least two sequence networks selected from the group of sequence networks consisting of a positive-sequence network, a negative-sequence network, and a zero-sequence network;
calculating a tilt value corresponding to a conjugate of a product of the incremental value of the sequence current, ΔIXL, and the current distribution factor phase angle, e −jψx ;
determining a distance to the fault based on the quotient of (a) an imaginary part of a product of the voltage of the faulted loop, VAL, and the tilt value divided by (b) an imaginary part of a product of a positive-sequence impedance, ZL1, the fault current value, I AG , and the tilt value; and
provide the distance to the fault during the pole-open condition, wherein the provided distance to the fault utilizes the impedance values of the at least two sequence networks to compensate for a voltage potential across an open pole of the three-phase transmission system.

11. The method of claim 10 , wherein phase B is in a pole-open condition during the fault such that a is equal to 1∠120°.

12. The method of claim 10 , further comprising:
reporting the calculated distance to the fault as a range based on an estimated error percentage.

13. A method, comprising:
identifying which one of three phases of a three-phase transmission system was in a pole-open condition during a fault between a first relay and a second relay;
selecting a corresponding complex operator, α, where the complex operator, α, is equal to 1 for a phase A open-pole, 1∠120° for a phase B open-pole, and (1∠120°) 2 for a phase C open-pole;
determining an impedance value ZL1 between the first relay and the second relay;
calculating a difference between a negative-sequence voltage, V2L, at the first relay and a negative-sequence voltage, V2R, at the second relay;
calculating a difference between a negative-sequence current, I2R, at the second relay and a positive-sequence current, I1R, at the second relay;
calculating a difference between a positive-sequence voltage, V1L, at the first relay and a positive-sequence voltage, V1R, at the second relay;
calculating a sum of a negative-sequence current, I2L, at the first relay and a negative-sequence current, I2R, at the second relay;
calculating a sum of the positive-sequence current, I1L, at the first relay and a positive-sequence current, I1R, at the second relay;
determining a distance to the fault by implementing an algorithm that at least approximately satisfies at least one of two distance equations:

Assignees

• Schweitzer Engineering Lab Inc

Inventors

• Benmouyal Gabriel
• Smyth Brian A

Classifications

• H02J13/12

  Monitoring network conditions, e.g. electrical magnitudes or operational status · CPC title

• G01R31/085 Primary

  in power transmission or distribution lines, e.g. overhead · CPC title