Phase current sudden change based earth fault protection method

A ground fault and sudden change technology, applied in emergency protection circuit devices, electrical components, etc., can solve the problems of line selection troubled by electric workers, weak fault current characteristics, and huge multiplication operations, and achieve high protection accuracy and reliability. performance, computational simplicity, and improved accuracy and reliability

Active Publication Date: 2016-08-31
长沙精科电力技术有限公司
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Problems solved by technology

[0002] my country's distribution network widely adopts the non-effective neutral point grounding mode. This mode of operation can effectively improve the reliability of power supply. However, when the single-phase grounding fault occurs, the fault current characteristics are weak, the arc is unstable and other factors, and the line selection problem has always been a problem. Difficulties Plagued by Power Workers
The main difficulties of the wavelet algorithm are: ① easily affected by factors such as wavelet basis functions and decomposition scales; ② a large number of layer-by-layer extraction and separation of sampled data, the amount of multiplication is very huge

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  • Phase current sudden change based earth fault protection method
  • Phase current sudden change based earth fault protection method
  • Phase current sudden change based earth fault protection method

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[0021] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0022] Such as figure 1 As shown, the earth fault protection method based on phase current sudden change of the present invention, its steps are:

[0023] S1: Online monitoring of the zero-sequence voltage of the distribution network, when the zero-sequence voltage exceeds the limit (that is, exceeds the voltage limit value), the transient phase current signal of each line is collected;

[0024] S2: Extract the transient phase current mutation amount of each line;

[0025] S3: Perform pairwise correlation analysis on the phase current mutation of each line to obtain the phase-to-phase correlation number [ρ AB ρ BC ρ CA ], the minimum correlation coefficient ρ between phases can be obtained by comparison min ;

[0026] S4: Judging the faulty line according to the size of the correlation coefficient. When the minimum correlatio...

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Abstract

The invention discloses a phase current sudden change based earth fault protection method which comprises the following steps: 1) online monitoring the zero sequence voltage of a power distribution network wherein when the zero sequence voltage exceeds the limit value of the voltage, the transient phase current signals of all lines are collected; 2) extracting the sudden changes in the transient phase current signals of all lines; 3) conducting two-on-two correlation analysis on the sudden changes in the transient phase current signals to obtain phase correlation coefficients [Rho AB, Rho BC Rho CA]; comparing for the smallest correlation coefficient Rho min; and 4) based on the identical correlation coefficients to find out the lines in fault. The method, with simple principles, is easy to perform for enhanced protection accuracy and reliability.

Description

technical field [0001] The invention mainly relates to the technical field of distribution network grounding, in particular to a grounding fault protection method based on phase current mutation. Background technique [0002] my country's distribution network widely adopts the non-effective neutral point grounding mode. This mode of operation can effectively improve the reliability of power supply. However, when the single-phase grounding fault occurs, the fault current characteristics are weak, the arc is unstable and other factors, and the line selection problem has always been a problem. Difficulties plaguing electricians. At present, the research on fault line selection has achieved some preliminary results, but the accuracy of line selection in practical applications is still low and needs to be further improved. [0003] The existing ground fault protection methods of distribution network mainly include three methods: injection signal method, steady state method and tr...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/26H02H7/22
CPCH02H7/22H02H7/262H02H7/263
Inventor 曾祥君刘谋海谷应科
Owner 长沙精科电力技术有限公司
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