Small grounding current system double-loop wire single-phase ground fault distance measuring method

Abstract

The invention provides a distance measuring method for a double return line single phase grounding fault of a small grounding current system. The method comprises the following steps: 1, double return lines in different positions are coded, and arranged in a microcomputer of a grounding transfer device in advance; and 2, a microcomputer carries out real time acquisition and calculation of phase voltage, line voltage and zero sequence voltage of a bus and zero sequence current of other circuits of a transformer substation, judges the grounding and grounding phase of the system, and gives a switch-on command to a split phase switch of the grounding phase, and a wave recording command at the same time when the single phase grounding fault occurs in the system; after wave recording; by the combination of the codes of the double return lines, the microcomputer carries out the line selecting operation through the measured zero sequence voltage and zero sequence current; and then by the measured double return line first line grounding current split current value equation, the measured double return line second line grounding current split current value equation, the measured flow-in fault point current value equation and the measured distance equation between the tail end and the fault point of the circuit, the microcomputer can work out the position of a grounding point when the grounding point of the double return lines is grounded, namely the distance between the tail end and the fault point of the circuit.

Description

technical field [0001] The invention belongs to a distance measuring method for a fault in a power system, in particular to a distance measuring method for a single-phase ground fault of a double circuit line in a small ground current system. Background technique [0002] At present, when a short-circuit fault occurs in the power system, due to the large short-circuit current, fault location is realized by using current and voltage as parameters, and the distance to the fault point can be known. However, when a single-phase ground fault occurs in a small ground current system, since the ground current is very small, it is only the ground capacitance current of the system, and its current magnitude is only related to the operation mode and grounding degree, but not to the grounding position, so it is difficult to Realize ground fault distance measurement. For this reason, the traditional method of manual inspection along the line is still being used in finding the grounding ...

AI Technical Summary

Problems solved by technology

However, when a single-phase ground fault occurs in a small ground current system, since the ground current is very small, it is only the ground capacitance current of the system, and its...

Images