CN-122017446-A - Fault identification method and system based on current traveling wave

CN122017446ACN 122017446 ACN122017446 ACN 122017446ACN-122017446-A

Abstract

The invention provides a fault identification method and system based on current traveling waves, which comprise the steps of collecting initial three-phase current traveling wave signals on a line after faults, extracting initial amplitude values of all phases of the initial three-phase current traveling wave signals, carrying out modulus transformation on the initial amplitude values of the initial three-phase current traveling wave signals to obtain single-phase quantities and multiple phase quantities, determining initial fault types from ground faults and interphase short-circuit faults according to the magnitude relation between the amplitude values of the single-phase quantities and a first preset threshold value, identifying final fault types and final fault phases by comparing the magnitude relation of the multiple phase quantities based on the determined initial fault types, outputting the fault identification results as fault identification results, and having the advantages of simplicity in calculation, rapidness in response, clear criteria and high reliability, and effectively improving the accuracy and adaptability of fault identification.

Inventors

CHEN TIANYING
WANG LEI
ZHANG WEIMING
WANG XIANZHI
GUO SHAOFEI
LI ZE
LIU SHIYAN
WANG XINRUI

Assignees

国网河北省电力有限公司电力科学研究院
国家电网有限公司

Dates

Publication Date: 20260512
Application Date: 20251203

Claims (10)

1. A fault identification method based on current traveling wave, comprising: collecting initial three-phase current traveling wave signals on a line after faults; extracting initial amplitude values of phases of the initial three-phase current traveling wave signals; modulus transformation is carried out on the initial amplitude value of the initial three-phase current traveling wave signal, so that single-phase quantity and multiple-phase quantity are obtained; Determining an initial fault type from the ground fault and the interphase short-circuit fault according to the magnitude relation between the amplitude of the single phasor and a first preset threshold value; based on the determined initial fault type, identifying a final fault type and a final fault phase by comparing the amplitude relations of the plurality of phase amounts as a fault identification result; and outputting the fault identification result.
2. The method for fault identification based on current traveling wave according to claim 1, wherein modulus transforming the initial amplitude of the initial three-phase current traveling wave signal to obtain a single-phase quantity and a plurality of phase quantities comprises: Adding the initial amplitudes of all phases of the initial three-phase current traveling wave signals to obtain an addition result, and taking one third of the addition result as single-phase quantity; Dividing the difference between the A phase and the B phase, the difference between the A phase and the C phase and the difference between the B phase and the C phase of the initial three-phase current traveling wave signal by three to obtain respective corresponding phase-to-phase quantities.
3. The fault identification method based on the current traveling wave according to claim 2, wherein modulus transformation is performed on the initial amplitude of the initial three-phase current traveling wave signal to obtain a single-phase quantity and a plurality of phase quantities, wherein the single-phase quantity and the plurality of phase quantities are represented by the following formulas: ; Wherein, the 、、 The initial amplitudes of the phase A, the phase B and the phase C in the initial three-phase current traveling wave signals are respectively; Is a single phasor; The phase amounts corresponding to the phase A and the phase B; the phase amounts corresponding to the A phase and the C phase; The corresponding phase amounts are B phase and C phase.
4. The method of fault identification based on traveling current waves according to claim 1, wherein determining an initial fault type from among a ground fault and an inter-phase short circuit fault according to a magnitude relation of the magnitude of the single-phase quantity and a first preset threshold value comprises: comparing the magnitude relation between the magnitude of the single phasor and a first preset threshold value; if the amplitude of the single phasor is greater than a first preset threshold, determining that the initial fault type is a ground fault; if the amplitude of the single phasor is smaller than or equal to a first preset threshold value, determining that the initial fault type is interphase short-circuit fault; the first preset threshold is a positive number determined according to the system noise level or field commissioning.
5. The current traveling wave based fault identification method of claim 4, wherein identifying a final fault type and a final fault phase by comparing magnitude relationships of the plurality of phase amounts based on the determined initial fault type comprises: when the initial fault type is a ground fault, comparing the magnitude relation of any two of the three phase quantities; if two of the three phase amounts are equal in amplitude and the third phase amount is smaller than the first preset threshold, judging that the final fault type is single-phase earth fault, and judging that the fault phase is a phase with uncorrelated third phase amount; If two of the three phase amounts are equal in amplitude and the third phase amount is greater than the first preset threshold, judging that the final fault type is an indirect fault, and the fault phase is a phase related to the third phase amount; if the magnitudes of the three phase amounts are equal, then the final fault type is determined to be a three-phase ground fault.
6. The current traveling wave based fault identification method of claim 4, wherein identifying a final fault type and a final fault phase by comparing magnitude relationships of the plurality of phase amounts based on the determined initial fault type comprises: When the initial fault type is interphase short-circuit fault, comparing the magnitude relation of any two of the three phase quantities; if two of the three phase amounts are equal in amplitude and the third phase amount is twice as large as the other two phase amounts, determining that the final fault type is an interphase fault and the fault phase is a phase related to the third phase amount; if the magnitudes of the three phase amounts are equal, then the final fault type is determined to be a three-phase ground fault.
7. The current traveling wave based fault identification method according to claim 4, wherein the final fault type and the final fault phase are identified by comparing the magnitude relation of the plurality of phase amounts based on the determined initial fault type, and as a fault identification result, comprising: When the initial fault type is a ground fault, the following steps are executed: if the amplitude of one phase amount is smaller than the other two phase amounts, judging that the single-phase earth fault exists; If the absolute value of the difference between the magnitudes of any two phase quantities is smaller than a first preset threshold value and the magnitude of the third phase quantity is larger than the first preset threshold value, judging that the two phases are in ground fault, wherein the fault phase is the two phases associated with the third phase quantity.
8. The current traveling wave based fault identification method according to claim 7, wherein the final fault type and the final fault phase are identified by comparing the magnitude relation of the plurality of phase amounts based on the determined initial fault type, and as a fault identification result, comprising: when the initial fault type is interphase short-circuit fault, executing the following steps: if the absolute value of the difference between the amplitude values of the two phase amounts is smaller than a first preset threshold value, and the absolute value of the difference between the amplitude value of the third phase amount and twice the amplitude value of the two phase amounts is smaller than the first preset threshold value, judging that the phase-to-phase short circuit fault exists, wherein the fault phase is the two phases associated with the third phase amount; And if the absolute values of the differences between the amplitudes of the three phase amounts are smaller than the first preset threshold value, judging that the three-phase short circuit fault exists.
9. The method of claim 1, wherein collecting the initial three-phase current traveling wave signal on the line after the fault comprises: and acquiring a signal corresponding to a first traveling wave head reaching a monitoring point on the line after the fault, and taking the signal as an initial three-phase current traveling wave signal.
10. A fault identification system based on a traveling current wave, comprising: the signal acquisition module is used for acquiring initial three-phase current traveling wave signals on the line after the fault; The current extraction module is used for extracting the initial amplitude value of each phase of the initial three-phase current traveling wave signal; the current transformation module is used for carrying out modulus transformation on the initial amplitude value of the initial three-phase current traveling wave signal to obtain single-phase quantity and a plurality of phase quantities; The initial fault module is used for determining an initial fault type from the ground fault and the interphase short-circuit fault according to the magnitude relation between the amplitude of the single-phase quantity and a first preset threshold value; the final fault module is used for identifying the final fault type and the final fault phase by comparing the amplitude relations of the phase quantities based on the determined initial fault type, and taking the final fault type and the final fault phase as a fault identification result; And the fault output module is used for outputting the fault identification result.

Description

Fault identification method and system based on current traveling wave Technical Field The invention relates to the technical field of relay protection of power systems, in particular to a fault identification method and system based on current traveling waves. Background The distribution network is an important component of the power system, and the operation reliability of the distribution network is directly related to the power supply quality. Line faults are common problems in power distribution networks, and mainly include interphase short circuits, ground faults and the like. The method for quickly and accurately identifying the fault type is a key for realizing quick fault isolation, recovering power supply and guaranteeing system safety. Existing fault identification methods rely primarily on steady state components or transient components. The method based on the steady-state component is easily influenced by factors such as transition resistance, load fluctuation and the like, and has insufficient reliability. However, although the transient component-based method, such as wavelet transformation and neural network, can utilize the initial fault information, the method generally has the problems of complex calculation, dependence on a large amount of training data, sensitivity to signal distortion and the like. Therefore, a fault identification method which is simple in principle, clear in criterion and independent of complex threshold values is urgently needed. Disclosure of Invention The invention provides a fault identification method and system based on current traveling waves, which are used for solving the technical problems of insufficient reliability and large operand in line fault identification in the prior art. In one aspect, the invention provides a fault identification method based on current traveling waves, which comprises the following steps: collecting initial three-phase current traveling wave signals on a line after faults; Extracting initial amplitude values of all phases of initial three-phase current traveling wave signals; modulus transformation is carried out on the initial amplitude value of the initial three-phase current traveling wave signal, and single-phase quantity and multiple-phase quantity are obtained; determining an initial fault type from the ground fault and the interphase short-circuit fault according to the magnitude relation between the amplitude of the single phasor and a first preset threshold value; based on the determined initial fault type, identifying a final fault type and a final fault phase by comparing amplitude relations of a plurality of phase amounts, and taking the final fault type and the final fault phase as a fault identification result; And outputting a fault identification result. According to the fault identification method based on the current traveling wave, modulus transformation is carried out on the initial amplitude of the initial three-phase current traveling wave signal to obtain single-phase quantity and multiple-phase quantity, and the fault identification method comprises the following steps: adding the initial amplitudes of all phases of the initial three-phase current traveling wave signals to obtain an addition result, and taking one third of the addition result as a single-phase quantity; Dividing the difference between the A phase and the B phase, the difference between the A phase and the C phase and the difference between the B phase and the C phase of the initial three-phase current traveling wave signal by three to obtain the respective corresponding phase-to-phase quantities. According to the fault identification method based on the current traveling wave, modulus transformation is carried out on the initial amplitude value of the initial three-phase current traveling wave signal, and single-phase quantity and multiple-phase quantity are obtained, wherein the following formula is shown: ; Wherein, the 、、The initial amplitudes of the phase A, the phase B and the phase C in the initial three-phase current traveling wave signals are respectively; Is a single phasor; The phase amounts corresponding to the phase A and the phase B; the phase amounts corresponding to the A phase and the C phase; The corresponding phase amounts are B phase and C phase. According to the fault identification method based on the current traveling wave, which is provided by the invention, according to the magnitude relation between the amplitude of the single-phase quantity and the first preset threshold value, the initial fault type is determined from the ground fault and the interphase short-circuit fault, and the fault identification method comprises the following steps: Comparing the magnitude relation between the magnitude of the single phasor and a first preset threshold value; if the amplitude of the single phasor is greater than a first preset threshold, determining that the initial fault type is a ground fault; if the amplitude of t