Transient based method for identifying faults in a high / medium voltage electric power transmission system

Patent metadata

Field	Value
Publication number	US-2022206055-A1
Application number	US-202017604823-A
Country	US
Kind code	A1
Filing date	Apr 16, 2020
Priority date	Apr 19, 2019
Publication date	Jun 30, 2022
Grant date	—

Abstract

The invention relates to a transient based method for identifying faults in an electric power transmission and/or distribution system (100) having at least one current transmission line (L12, L13, L23) comprising the following steps: —generation of a physical model of the at least one current transmission line (L12, L13, L23), the physical model depending on the fault parameters and describing the behavior of voltage and/or current transients due to the fault in the at least one current transmission line, fault parameters comprising a fault location parameter on said current transmission line (L12, L13, L23) and a fault impedance parameter, —measurement of voltage and/or currents evolution at least at one specific location in the said power system (100), —iterative simulation of the voltage and/or current evolution by the physical model at the measurement point with a set of fault parameters where at each step of iteration, simulated and measured voltage and/or current evolutions are compared and the set of fault parameters is adapted according to a convergence criterion, —identification of a fault with its fault parameters when convergence of the measured voltage and/or current evolutions and simulated voltage and/or current evolutions is reached in a limited number of iterations.

First claim

1 . A transient based method for identifying faults in an electric power transmission and/or distribution system comprising a current transmission line, said method comprising
generating a physical model of the current transmission line, the physical model depending on fault parameters and describing the behavior of voltage and/or current transients due to a fault in the current transmission line, said fault parameters comprising a fault location parameter on said current transmission line and a fault impedance parameter, measuring voltage and/or current evolution at a specific location in said power system, iteratively simulating the voltage and/or current evolution by the physical model at a measurement point with a set of fault parameters, wherein each step of iteration comprises comparing simulated and measured voltage and/or current evolutions and adapting the set of fault parameters according to a convergence criterion, and identifying a fault and fault parameters thereof upon having reached convergence of the measured voltage and/or current evolution and the simulated voltage and/or current evolution.

2 . The method according to claim 1 , wherein the measurements of voltage and/or current evolution are carried out at several specific locations in the said power system, each corresponding to a measurement point and wherein the steps of iteratively simulating of the voltage and/or current evolution and identifying a fault with its fault parameters are carried out for each measurement point independently from the other measurement points.

3 . The method according to claim 1 , wherein the physical model is based on a telegraph equation for describing the fault parameters and the behavior of travelling waves due to the fault in said electrical power transmission and/or distribution system.

4 . The method according to claim 3 , wherein only traveling waves are taken into account when iteratively simulating the voltage and/or current evolution that can reach the measurement point before a predetermined maximum time t max between one and ten milliseconds.

5 . The method according claim 1 , further comprising extending the physical model to take into account soil resistivity.

6 . The method according to claim 5 , wherein extending the physical model for taking into account soil resistivity comprises implementing a filtering function.

7 . The method according to claim 1 , wherein said electrical power transmission and/or distributor system is a high or medium voltage DC grid comprising overhead current transmission lines and/or underground and/or submarine current transmission lines.

8 . The method according to claim 1 , wherein said electrical power transmission and/or distributor system is a high or medium voltage AC grid.

9 . The method according to claim 1 , wherein said physical model takes into account modal voltage and current.

10 . The method according to claim 1 , wherein the convergence criterion comprises the minimization of a cost function of the difference of simulated and measured voltage and/or current evolutions.

11 . The method according to claim 1 , wherein identifying identification of a fault comprises verifying that the obtained fault parameters belong to a predefined validity domain.

12 . The method according to claim 1 , wherein each iteration step comprises completing voltage and/or current evolutions at specific locations in said electrical power transmission and/or distribution system with ongoing measurements at said measurement point.

13 . The method according to claim 1 , wherein the specific location is at one of an end of said current transmission line (L 12 , L 13 , L 23 ), a relay, a breaker module, and a station.

14 . The method according to claim 1 , further comprising detecting unusual behavior with respect to a nominal functioning of the electrical power transmission and/or distribution system and thereafter iteratively simulating the voltage and/or current evolution by the physical model.

15 . The method according to claim 14 , wherein detecting said unusual behavior comprises detecting at least one of a voltage drop, a current increase, and a crossing of a threshold.

16 . The method according to claim 1 , further comprising, after having identified said fault, generating an output in order to activate protection circuits in said electrical power transmission and/or distribution system.

17 . An apparatus comprising
a fault-identification module for identifying faults in an electrical power transmission and/or distribution system having a current transmission line (L 12 , L 13 , L 23 ) the fault-identification module being configured for:
memorization of a physical model of the electrical power transmission and/or distribution system with said current transmission line, the physical model describing fault parameters and behavior of travelling waves due to a fault in the electrical power transmission and/or distribution system and, in case of a fault, fault parameters comprising a fault-location parameter on said current transmission line (L 12 , L 13 , L 23 ) and a fault-impedance parameter,
measurement of voltage and/or current evolution at a specific location in said power system,
iterative simulation of the voltage and/or current evolution by the physical model at the measurement point with a set of fault parameters, wherein, at each iteration of said iterative simulation, simulated and measured voltage and/or current evolutions are compared and the set of fault parameters is adapted according to a convergence criterion,
identification of a fault and fault parameters thereof when convergence of the measured voltage and/or current evolutions and simulated voltage and/or current evolutions has been reached.

18 . The apparatus according to claim 17 , wherein the physical model is based on a telegraph equation for describing the fault parameters and the behavior of travelling waves due to the fault in said electrical power transmission and/or distribution system.

19 . The apparatus according to claim 17 , wherein the physical model is extended to take into account soil resistivity.

20 . The apparatus of claim 17 , further comprising a high or medium voltage electric power transmission and/or distribution system that comprises said fault identification module for controlling at least one protection circuit in a high/medium voltage electric power transmission and/or distribution system in case of a fault identification.

Assignees

• Inst Supergrid
• Univ De Paris Xi Paris Sud
• Univ Grenoble Alpes

Inventors

• Verrax Paul
• Bertinato Alberto
• Kieffer Michael
• Raison Bertrand
• Alglave Nathan

Classifications

• H02J13/12

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

• Y02E60/60

  Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD] · CPC title

• Y04S10/20

  using protection elements, arrangements or systems · CPC title

• Y04S10/30

  State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge · CPC title

• H02J3/36

  Arrangements for transfer of electric power between AC networks via high-voltage DC [HVDC] links; Arrangements for transfer of electric power between generators and networks via HVDC links · CPC title