Fault Line Selection Method for Resonant Grounding System Using Waveform Time Domain Feature Clustering

Abstract

The invention relates to a resonant earthed system fault line selection method utilizing waveform time domain feature clustering. The resonant earthed system fault line selection method comprises the following steps of 1 performing histogram decomposition on a half cyclic wave transient-state zero-sequence current waveform of each line after a resonant earthed system single-phase earth fault to obtain a histogram of time domain features reflecting the transient-state zero-sequence current waveforms of all of lines after the fault, and adopting a relative entropy reflecting state difference to establish a relative entropy matrix S including fault polarity information based on the time domain features reflecting the transient-state zero-sequence current waveforms of all of lines after the fault; 2 establishing a comprehensive amplitude matrix F3 including fault polarity information; 3 combining the relative entropy matrix S with the comprehensive amplitude matrix F3 to establish a comprehensive relative entropy feature matrix XS including transient-state zero-sequence current waveform fault information, utilizing a threshold-setting-free fuzzy kernel-clustering algorithm to perform clustering on the comprehensive relative entropy feature matrix XS, further distinguishing fault lines. The resonant earthed system fault line selection method improves the automation degree of fault line selection.

Description

Technical field [0001] The invention relates to the technical field of relay protection of intelligent power distribution systems, and in particular to a method for fault line selection of a resonance grounding system using waveform time domain feature clustering. Background technique [0002] my country's 6-35kV distribution network mainly adopts small current grounding methods. The single-phase grounding fault rate is the highest under the small current grounding mode, accounting for more than 80% of the distribution network faults. Because there is no direct electrical connection between the neutral point and the earth or a series reactor is connected in the small current grounding system, the short-circuit current is very small, and the line voltage between the three phases remains symmetrical, which has no effect on the power supply of the load. Under normal circumstances, it is allowed to continue to run for 1 to 2 hours without immediately tripping. However, after single...

AI Technical Summary

Problems solved by technology

[0004] In the existing method of using the similarity between the transient zero-sequence current waveforms after the fault to realize the fault line selection of the resonant grounding system, only through the similarity of the charging and discharging process of the non-faulted line after the fault or the similarity of the zero-sequence current waveform after the observation simulation To describe the similarity between zero-sequence current waveforms, there is no explanation for the similarity principle

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