An online detection method for high-resistance grounding faults of distribution lines

A high-resistance ground fault and high-resistance fault technology, applied in fault location, spectrum analysis/Fourier analysis, etc., can solve the problems of difficult to use distribution lines, complex surrounding environment, and easy occurrence of high-resistance ground faults. The effect of reliable data support, high technical reliability, and reliable guiding opinions

Inactive Publication Date: 2016-08-31
HARBIN UNIV OF SCI & TECH +1
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Problems solved by technology

6~10kV distribution lines are close to users, and the surrounding environment is complex, and high-resistance ground faults are prone to occur, so the online monitoring and detection methods for distribution lines are of great research value
It has a high accuracy rate for high-resistance ground faults with a fault current above 5A, but the application range of this scheme is based on transmission lines with a voltage level of 110kV and above, and it is difficult to use for distribution lines

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  • An online detection method for high-resistance grounding faults of distribution lines
  • An online detection method for high-resistance grounding faults of distribution lines

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Embodiment Construction

[0024] An online detection method for a high-resistance grounding fault of a distribution line is specifically implemented as follows:

[0025] 1) Determine the fault characteristic harmonic frequency according to the line topology.

[0026] 2) On-line monitoring of the zero-sequence voltage of the feeder line on the secondary side of the transformer to obtain a sampling value f(n) of one cycle, n=1, 2······N, N is an integer, and the value is between 120 and 240 .

[0027] 3) By performing FFT analysis on the sampling value sequence, the analysis spectrum is obtained with the power frequency voltage as the fundamental wave.

[0028] 4) Verify that frequency f occurs N : The characteristic harmonic amplitude of 1000~5000Hz reaches the peak mutation characteristic of 5%~7% of the fundamental wave amplitude. If the discrimination condition of high-resistance ground fault is met, it is identified as a high-resistance ground fault.

[0029] 5) Estimate the fault resistance val...

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Abstract

The invention discloses an online detection method for high-resistance grounding faults of power distribution lines. By measuring the zero-sequence voltage waveform within 2 to 3 cycles after the occurrence of high-resistance grounding faults, the harmonic spectrum contains high-resistance grounding faults. The fault information can be used for online detection of high-resistance grounding faults, and belongs to the field of power system protection and control. This method collects the zero-sequence voltage harmonics of the transformer secondary side feeder, determines the fault characteristic harmonic frequency (usually between 1000 and 5000 Hz) according to the line topology, and judges whether the line has high voltage by detecting the harmonic amplitude and frequency. ground fault. This method is especially suitable for small current grounding systems of 10kV and below, and only needs to collect zero-sequence voltage signals for analysis. Compared with the existing identification methods, the information collection is more convenient, the sensitivity is higher, it can be effectively distinguished from other working conditions and fault types, and the rejection and misoperation are reduced, and the identification is more accurate.

Description

technical field [0001] The invention belongs to the field of power system protection and control, and in particular relates to a detection method for high-resistance grounding faults of low-voltage (6-10kV) power distribution lines in small-current grounding systems. technical background [0002] Single-phase ground fault is a common fault in power system, which is not serious hazard itself, but it is very easy to cause more serious accidents. It is found from the field fault recording analysis that a considerable part of all phase-to-phase faults develops from single-phase grounding faults. 6~10kV distribution lines are close to users, and the surrounding environment is complex, and high-resistance ground faults are prone to occur. Therefore, online monitoring and detection methods for distribution lines are of great research value. The line generally adopts a low-current grounding system. When a single-phase high-resistance grounding fault occurs in the system, the short-...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/08G01R23/16
Inventor 周封刘健王丙全王晨光郝婷崔博闻朱瑞李伟力胡海涛刘小可
Owner HARBIN UNIV OF SCI & TECH
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