Transient zero sequence current-based single phase earth fault discrimination method

Abstract

The invention discloses a transient zero sequence current-based single phase earth fault discrimination method comprising the following steps: in step A, power distribution network zero sequence voltage magnitude is detected via all power distribution terminals, whether a single phase earth fault occurs is determined, step B is executed if the fault occurs, otherwise step A is executed in a circulating manner; in step B, when the earth fault occurs, zero sequence voltage is subjected to derivation operation via the power distribution terminals, polarities of a transient zero sequence current and a zero sequence voltage derivative are compared, and a line having the single phase earth fault is determined; in step C, a line with opposite polarities is chosen as the line having the fault, andthe power distribution terminals send earth fault blocking signals carrying grade information to power distribution terminals for a line which is one level higher; in step D, according to variation of transient zero sequence current amplitudes of all detection points on the line chosen in step C, a small current earth fault is positioned.

Description

technical field [0001] The invention relates to a fault location method, in particular to a single-phase ground fault discrimination method based on transient zero-sequence current. Background technique [0002] The feeder terminal unit (FTU for short) has the functions of remote control, remote signaling, and fault detection, and communicates with the master station of distribution automation to provide the operation status of the distribution system and various parameters that are information required for monitoring and control, including switch status and power parameters. , phase-to-phase fault, ground fault, and fault parameters, and execute the commands issued by the power distribution master station, adjust and control the power distribution equipment, and realize functions such as fault location, fault isolation, and rapid restoration of power supply in non-faulty areas. FTU is an intelligent terminal device installed in the power distribution room or feeder. It can...

AI Technical Summary

Problems solved by technology

[0005] 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 discrimination method 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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