Single-phase earth fault direction judgment and processing method of small current grounding system

Abstract

The invention relates to a single-phase earth fault direction judgment and processing method of a small current grounding system. In terms of a fault direction judgment method, the session which a single-phase fault point belongs to on a main line is judged according to zero-sequence currents, zero-sequence voltage and the included angle relation between the zero-sequence currents and the zero-sequence voltage tested through a section switch on the main line where a single-phase earth fault occurs, the fault session is isolated according to the judgment result, and normal power supply of a non-fault session line is guaranteed to the largest extent. According to the judgment and processing method, the single-phase earth fault session of the main line can be automatically isolated, and power supply reliability of a power distribution network is improved; additionally, according to the single-phase grounding direction judgment method, a main line boundary function is embedded in the section switch of a 10kV feeder line, the range in power failure caused by the single-phase earth fault can be shortened to the largest extent, and accordingly reliability and safety of power supply are improved.

Description

technical field [0001] The invention relates to a single-phase grounding fault direction discrimination and processing method in a small current grounding system. Background technique [0002] my country's 10kV power distribution system adopts the operation mode of neutral point indirect grounding (small current grounding system) - that is, the neutral point is not grounded or the neutral point is grounded through the arc suppression coil, and the neutral point is not directly grounded. In the power distribution network, single-phase grounding is a common fault, especially in rainy seasons, strong winds and other severe weather conditions, single-phase grounding faults occur frequently. [0003] After a single-phase ground fault occurs in a low-current grounding system, the fault phase-to-ground voltage decreases, and the phase-to-ground voltage of the non-faulted two phases increases, but the line voltage is still symmetrical, so the continuous power supply to users is not a...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to address the deficiencies of the prior art, and provide a method for judging the direction of a single-phase ground fault in a small-current grounding system, so as to overcome the problems in the prior art that the basis for judging a single-phase ground fault is not accurate enough, and the fault discovery is not timely.

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