High-resistance ground fault line selection method for small-current grounding system

Abstract

The invention relates to a high-resistance ground fault line selection method for a small-current grounding system. According to the method, a plurality of feeder terminals arranged on each of all monitoring points of a line collect the zero-sequence current and the zero-sequence voltage of each monitoring point in real time. When the collected amplitude of the zero-sequence voltage of a bus is within a threshold section, the occurrence of a high-impedance grounding fault is detected and the fault location is further conducted. According to a fault line selection result, the transient-state zero-sequence current at each monitoring point on the upstream or downstream of each section of the fault line is projected onto the transient-state zero-sequence voltage of the bus, and then projection coefficients calculated. After that, the projection coefficients of the projectional components of all the transient-state zero-sequence currents at each of all monitoring points are compared, and the downstream section of a monitoring point with a largest projection coefficient is adopted as a fault section. According to the technical scheme of the invention, the fault location problem of the high-impedance grounding fault of the small-current grounding system is solved. Meanwhile, a location method based on the comparison of the projection coefficients of the projectional components of all the transient-state zero-sequence currents at each of all monitoring points on the upstream or downstream of each section of the fault line is provided. Therefore, the method has a wide practical application value.

Description

technical field [0001] The invention relates to the field of distribution network fault detection, in particular to a method for selecting a high-impedance grounding fault line in a small current grounding system. 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 ground fault occurs on the distribution line, which makes the system run ...

AI Technical Summary

Problems solved by technology

[0005] In view of this, the purpose of the present invention is to provide a method for line selection of high-resistance grounding faults in small-current grounding systems, which solves the problem of positioning high-resistance grounding faults in small-current grounding systems and has extensive practical application value

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