High-resistance grounding fault positioning method based on transient current projection coefficient difference comparison

Abstract

The invention discloses a high-resistance grounding fault positioning method based on transient current projection coefficient difference comparison, which is characterized in that when a system has a high-resistance grounding fault, a substation terminal starts, a fault line is selected, and a line selection result and fault line outlet zero-sequence current acquisition data are reported to a master station; when a sudden change of zero-mode voltage or zero-mode current exceeds a preset threshold, each feed line terminal starts, and fault zero-sequence voltage and current acquisition data is reported to the master station; the master station receives zero-sequence voltage and current acquisition data of each monitoring point of the substation terminal and feed lines, respectively extracts transient components thereof and does not perform processing on sound line terminal data; projecting the transient zero-sequence current of each monitoring point to transient zero-sequence voltage of a bus, and calculating a projection coefficient of the transient zero-sequence current of each monitoring point; calculating the difference of the transient zero-sequence current projection coefficients of upstream and downstream monitoring points of each segment; and selecting a segment with the greatest difference to be a fault segment. The high-resistance grounding fault positioning method solves a problem of positioning a high-resistance grounding fault in a resonant grounding system and has wide practical application values.

Description

technical field [0001] The invention relates to the technical field of fault location, in particular to a high-resistance grounding fault location method based on the difference comparison of transient current projection coefficients. Background technique [0002] Affected by factors such as natural environment and low overhead distance of lines, single-phase high-resistance grounding faults through non-ideal conductors often occur in distribution networks, such as conductors falling on grass, roads, sand, and ponds. According to incomplete statistics, high-resistance grounding accounts for about 5-10% of the total ground faults. More than 12% of the ground faults in the French resonant grounding system are high-resistance ground faults. Due to the small high-resistance grounding fault current (usually Class A) and the instability of the fault point, it is difficult to detect when a permanent high-resistance grounding fault occurs in the distribution line, making the system...

AI Technical Summary

Problems solved by technology

The existing low-resistance (metallic) ground fault location has not been completely resolved, and none of them are suitable for high-resistance ground faults. Therefore, there is no time to take into account the research on the high-resistance ground fault location technology with unobvious fault electrical characteristics, so it is rarely There are few relevant research reports

[0004] For the resonant grounding system, the power frequency current itself has no obvious fault characteristics and cannot be directly used for fault detection (the active component of the power frequency current is theoretically feasible, but the content is small and easily affected by TV / TA transmission characteristics, and there are great difficulties in practical use)

In the existing technology, the downstream section of the detection point with the largest projection coefficient is selected as the fault section. Since the projection coefficients of each detection point upstream of the fault point are small positive numbers and the difference is not large, it is easy to be disturbed and cause positioning errors

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