Single-phase grounding fault intelligent line selection method for small current grounding system of power distribution network

By obtaining the instantaneous value of zero-sequence voltage and discrete wavelet packet decomposition in the low-current grounding system of the distribution network, and combining the morphological difference value and the total energy weight, the problem of accuracy in single-phase grounding fault location was solved, and higher location accuracy was achieved.

CN122238942BActive Publication Date: 2026-07-21SHANGHAI JUNSHI ELECTRICAL TECH
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Patent Information

Application Number
CN202610702145.9
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2026-05-21
Publication Date
2026-07-21
Estimated Expiration
2046-05-21

AI Technical Summary

Technical Problem

Existing technologies have low accuracy in locating single-phase grounding faults in low-current grounding systems of distribution networks. This is mainly due to the high-frequency transmission error of the current transformers configured in the data acquisition channels at the bottom of the substation, which makes it impossible to eliminate measurement errors and is susceptible to weak white noise interference.

Method used

By obtaining the instantaneous value of the zero-sequence voltage of the substation bus, the transient signal interception window is determined. The high-frequency component signal of the zero-sequence current is extracted by discrete wavelet packet decomposition. Combined with the morphological difference value and the total energy weight, the single-phase grounding fault line is selected.

Benefits of technology

It effectively eliminates high-frequency transmission error interference from instrument transformers, identifies and suppresses weak white noise, and improves the accuracy of single-phase grounding fault location.

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Abstract

The present application relates to the technical field of power system grounding fault detection, in particular to a single-phase grounding fault intelligent line selection method for a small-current grounding system of a distribution network, which locks a transient signal interception window through a zero-sequence voltage instantaneous value, accurately extracts a zero-sequence current high-frequency component signal corresponding to a high-frequency frequency band level by using discrete wavelet packet decomposition, and determines a morphological difference value based on an energy distribution deviation of a feeder compared with other feeders, so as to convert absolute magnitude discrimination into a comparison of frequency band distribution forms, and eliminate the interference of high-frequency transformation errors of underlying mutual inductors on a decision result; in combination with a total energy weight representing a physical scale of a signal, a morphological distribution artifact generated by weak white noise is identified and suppressed in a targeted manner; by fusing the morphological difference value and the total energy weight, deep mining of a fault branch distribution structure feature and adaptive shielding of noise interference are realized, so that the single-phase grounding fault intelligent line selection for the small-current grounding system of the distribution network is more accurate.
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