Single-phase earth fault judgment method for transient zero-sequence current

Abstract

The invention discloses a single-phase earth fault judgment method for transient zero-sequence current. The method comprises steps as follows: step A, each power distribution terminal detects zero sequence voltage value of a power distribution network to judge whether a single-phase earth fault occurs, if the fault occurs, the operation enters the step B, and otherwise, the step A is repeated; step B, a traditional zero-sequence current transformer is mounted at the wire outlet end of each feeder of a substation bus, a zero-sequence current power frequency signal of each traditional zero-sequence current transformer is sent to a substation detection device through a traditional zero-sequence current transformer secondary circuit, and a circuit where the single-phase earth fault occurs is judged according to the zero-sequence current signal; step C, the fault circuit is selected, and the power distribution terminal sends an earth fault blocking signal with grade information to the powerdistribution terminal of the upper level; step D, under the action of compensation of arc suppression coils, zero-sequence current amplitude between a fault point and the substation changes, and amplitude change information, detected by the substation, of zero-sequence current of each segmented node is analyzed, so that the single-phase earth fault point of the circuit is positioned.

Description

technical field [0001] The invention relates to the field of electric power, in particular to a single-phase ground fault judgment method for transient zero-sequence current. Background technique [0002] There will be hand-in-hand connection lines between different substations. When a single-phase ground fault occurs, it is necessary to determine which substation feeder has a single-phase ground fault, so as to perform accurate single-phase ground fault processing. When a single-phase ground fault occurs, the distribution network connected together has the same change in the neutral point displacement voltage of the fault characteristics, and it is difficult to quickly judge the fault area according to the characteristics of the single-phase ground fault. If the fault area is judged, the fault treatment cannot be carried out. Therefore, when a single-phase ground fault occurs, it is very necessary to quickly judge the fault area and take timely fault treatment. Contents o...

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is that when a small current single-phase grounding fault occurs in the system, the fault current is very small and the fault signal is weak, which makes fault detection, line selection and positioning very difficult. The single-phase ground fault judgment method of sequence current solves the problem that when a small current single-phase ground fault occurs in the system, the fault current is very small and the fault signal is weak, which makes fault detection, line selection and location very difficult

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