Method and system for locating a fault in a mixed power transmission line

Patent metadata

Field	Value
Publication number	US-11047892-B2
Application number	US-201616315665-A
Country	US
Kind code	B2
Filing date	Jul 8, 2016
Priority date	Jul 8, 2016
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

A method and system is provided for locating a fault in a mixed power transmission line. The method is implemented by an Intelligent Electronic Device (IED) of the mixed line. The IED detects a travelling wave from one or more signals received from one or more measurement equipment. Thereafter, the IED identifies a line section with the fault, and generates two or more estimates for the location of the fault based on a time difference between arrival of two peaks of the travelling wave, a velocity of propagation of the travelling wave in the line section identified with the fault, and a length of one or more line sections. The IED determines the location of the fault based on a comparison of each estimate with a threshold, wherein the threshold is estimated based on the one or more signals, equivalent source impedance of each source and total line impedance.

First claim

The invention claimed is:

1. A method for locating a fault in a mixed power transmission line comprising two or more line sections, the method comprising:
receiving, by an Intelligent Electronic Device (IED) of the mixed power transmission line, one or more signals from one or more measurement equipment connected to the mixed power transmission line;
detecting, by the IED, a travelling wave from the one or more signals received from the one or more measurement equipment, wherein the travelling wave is generated due to the fault in a line section where the fault is located of the two or more line sections;
identifying, by the IED, the line section where the fault is located from the one or more signals received from the one or more measurement equipment, including determining a first peak of the travelling wave and at least one travelling-wave characteristic of the first peak chosen from a peak width, a rise time, and a discharge time and comparing the at least one travelling-wave characteristic of the first peak with a corresponding threshold value for each junction of one or more junctions that connect consecutive line sections of the two or more line sections of the mixed power transmission line, wherein the corresponding threshold value for each junction is predetermined for each junction of the one or more junctions and is stored in the IED;
generating, by the IED, two or more estimates of a location of the fault within the line section where the fault is located, wherein each estimate of the two or more estimates is generated based on a time difference between arrival of two peaks of the travelling wave, a velocity of propagation of the travelling wave in the line section where the fault is located t, and a length of one or more line sections of the two or more line sections; and
determining, by the IED, the location of the fault within the line section where the fault is located based on a comparison of each estimate of the two or more estimates with a threshold for the location of the fault, wherein the threshold for the location of the fault is estimated based on the one or more signals, equivalent source impedance of each of multiple sources of the mixed power transmission line, and total line impedance of the mixed power transmission line.

2. The method of claim 1 , wherein the two peaks of the travelling wave comprise the first peak of the travelling wave and a second peak of the travelling wave respectively.

3. The method of claim 1 , wherein determining the location of the fault comprises selecting an estimate of the two or more estimates that is closest to the threshold for the location of the fault.

4. The method of claim 1 , wherein a first estimate of the two or more estimates corresponds to a first half of the line section where the fault is located, and a second estimate of the two or more estimates corresponds to a second half of the line section where the fault is located.

5. The method of claim 1 , further comprising estimating the threshold for the location of the fault based on voltage and current measurements obtained from the one or more measurement equipment, equivalent source impedance of each source of the mixed power transmission line, and total line impedance of the mixed power transmission line.

6. The method of claim 1 , wherein the threshold for the location of the fault comprises a single value for the location of the fault or a range of values for the location of the fault.

7. The method of claim 6 , further comprising determining the range of values for the location of the fault based on an estimation error, a measurement error, or both.

8. The method of claim 6 , wherein determining the location of the fault within the line section where the fault is located based on the comparison of each estimate of the two or more estimates with the threshold for the location of the fault comprises determining each estimate of the two or more estimates that is within the range of values.

9. The method of claim 8 , wherein determining the location of the fault within the line section where the fault is located based on the comparison of each estimate of the two or more estimates with the threshold for the location of the fault further comprises determining the location of the fault based on each estimate of the two or more estimates that is within the range of values.

10. A method comprising:
detecting, by an Intelligent Electronic Device (IED), a travelling wave from one or more signals received from one or more measurement equipment of a mixed power transmission line;
identifying, by the IED, a line section of the mixed power transmission line having a fault by comparing a characteristic of the travelling wave with a corresponding threshold for each junction of a plurality of junctions of the mixed power transmission line;
generating, by the IED and based on the identified line section and a time difference between arrival of two peaks of the travelling wave, at least two estimates of a location of the fault within the identified line section; and
determining, by the IED, the location of the fault within the identified line section by comparing the at least two estimates of the location of the fault to a reference location determined as a function of a total line impedance of the mixed power transmission line.

11. The method of claim 10 , wherein comparing the characteristic of the travelling wave with the corresponding threshold for each junction of the plurality of junctions comprises comparing a peak width of a peak of the travelling wave with a corresponding threshold value for each junction of the plurality of junctions.

12. The method of claim 10 , wherein comparing the characteristic of the travelling wave with the corresponding threshold for each junction of the plurality of junctions comprises comparing a rise time of a peak of the travelling wave with a corresponding threshold value for each junction of the plurality of junctions.

13. The method of claim 10 , wherein comparing a characteristic of the travelling wave with a corresponding threshold for each junction of the plurality of junctions comprises comparing a discharge time of a peak of the travelling wave with a corresponding threshold value for each junction of the plurality of junctions.

14. The method of claim 10 , wherein detecting the travelling wave from the one or more signals comprises:
applying a Clark transformation to the one or more signals;
obtaining aerial mode components and ground mode components from the one or more signals;
filtering out, as a function of the aerial mode components, noise from the one or more signals; and
extracting the travelling wave from a predetermined frequency band of the one or more signals.

15. The method of claim 14 , further comprising extracting a travelling wave from each phase of a multiphase alternating current signal.

16. The method of claim 10 , wherein determining the location of the fault within the identified line section by comparing the at least two estimates of the location of the fault to the reference location determined as the function of the total line impedance of the mixed power transmission line comprises selecting, as the location of the fault within the identified line section, an estimate of the location that is closest to the reference location.

17. The method of claim 10 , wherein the reference location is further determined by impedances of sources connected to the mixed power transmission line.

18. The method of claim 17 , further comprising determining, by the IED, a range of reference locations

Assignees

• Abb Power Grids Switzerland Ag

Inventors

• Obbalareddi Demudu Naidu
• Purohit Amit
• Srivastava Sachin
• Wang Jianping

Classifications

• G01R31/088

  Aspects of digital computing · CPC title

• H02H3/40

  responsive to ratio of voltage and current · CPC title

• G01R27/16 Primary

  Measuring impedance of element or network through which a current is passing from another source, e.g. cable, power line · CPC title

• G01R31/11

  using pulse reflection methods · CPC title

• G01R31/085

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