Low-current single-phase grounding fault line selection method based on multi-criterion integration

Abstract

The invention discloses a low-current single-phase grounding fault line selection method based on multi-criterion integration. The method includes that a symbol t is used for indicating transient-state component strength, and a symbol r is used for indicating reliability; the higher the reliability r is, the higher the line selection accuracy is when a wavelet and energy method is adopted, and the line selection accuracy descends as the r is reduced and descends in an accelerated manner; when r is larger than or equal to 0.8 and smaller than or equal to 1, line selection accuracy is up to 99% when a line selection method based on transient-state component is adopted; when r is larger than or equal to 0 and smaller than or equal to 0.4, line selection accuracy of a line selection method based on transient-state component descends obviously, so that the line selection method based on steady-state component is unsuitable for adoption; when r is larger than or equal to 0.4 and smaller than or equal to 0.8, an integration method is started for line selection. The method utilizes both transient-state information of fault and steady-state information, so that the defect of single criterion is overcome to certain extent, and complementing of advantages of a transient-state algorithm and a steady-state algorithm is realized.

Description

technical field [0001] The invention relates to the field of small current single-phase ground faults, in particular to a line selection method for small current single-phase ground faults based on multi-criteria fusion. Background technique [0002] Most of my country's 6kV~66kV distribution network adopts a small current grounding system. Most of the faults in the small current grounding system are single-phase grounding faults. When a single-phase ground fault occurs, the non-faulty phase voltage rises to the line voltage, and if intermittent arcing grounding occurs, it will also cause arcing grounding overvoltage, and with the increase of feeder lines, the capacitive current will also increase. Long-term operation will cause the fault to expand into two or more points of grounding short circuit, or even phase-to-phase short circuit, which seriously threatens the safety of the system. Therefore, fault line selection is an important prerequisite for accurately locati...

AI Technical Summary

Problems solved by technology

The energy method and wavelet singularity method using transient components for line selection have a great relationship with the number of transient components contained in the fault information, but the transient components decay quickly and are difficult to extract, so if only using Transient components are used for fault line selection, and the line selection results are inaccurate in the case of few transient components

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