Small-current grounding system high-resistance grounding fault positioning method based on transient current projection component amplitude comparison

Abstract

A small-current grounding system high-resistance grounding fault positioning method based on transient current projection component amplitude comparison belongs to the field of power distribution network fault detection. The method settles a problem of small-current grounding system high-resistance grounding fault positioning and is a positioning method which utilizes projection component amplitude comparison of transient zero-sequence current of each monitoring point at upstream and downstream of each segment on bus transient zero-sequence voltage. According to a fault line selecting result, the projection components of the transient zero-sequence current at upstream and downstream of each segment in a faulted line on the bus transient zero-sequence voltage are calculated. A characteristic value which comprises projection component polarity and amplitude information of each monitoring point is compared. One second value of the characteristic value of a largest projection component is set as a threshold. The segment in which the difference between the characteristic values of the projection components of the transient zero-sequence current at upstream and downstream of the segment is larger than the threshold is selected as the faulted segment. If the difference between the characteristic values of the projection components of the transient zero-sequence current at upstream and downstream of each segment is lower than the threshold, a line end fault is determined. The small-current grounding system high-resistance grounding fault positioning method settles a problem of positioning the high-resistance grounding fault in the small-current grounding system and furthermore has high practical application value.

Description

technical field [0001] The invention relates to a high-resistance fault line selection method for a small-current grounding system, which is suitable for a power distribution system in a small-current grounding mode, and belongs to the field of distribution network fault detection. Background technique [0002] Affected by factors such as natural environment and low overhead line distance, single-phase high-resistance grounding faults through non-ideal conductors often occur in distribution networks, such as wires falling on grass, roads, sandy land, ponds, etc. According to incomplete statistics, high resistance grounding accounts for 5-10% of the total number of grounding faults. More than 12% of the ground faults in the French small current grounding system are high-resistance ground faults. Due to the small high-resistance ground fault current (generally A level) and the instability of the fault point, it is difficult to be detected when a permanent high-resistance grou...

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 small current grounding systems, the power frequency current itself has no obvious fault characteristics and cannot be directly used for fault detection (the active component of 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 )

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