Method and device for preventing same-list-phase fault zero-sequence protection operation refusal and system

Abstract

The invention relates to the technical field of power system relay protection, and particularly discloses a method for preventing a multi-loop same-list-phase fault zero-sequence protection operationrefusal. The method comprises the following steps that: when a main transformer zero-sequence protection device detects a fault signal, the main transformer zero-sequence protection device sends a zero-sequence protection starting signal to a line zero-sequence protection device; and the line zero-sequence protection device analyzes the relationship between the current line zero-sequence current and the zero-sequence starting current according to the zero-sequence protection starting signal, analyzes the type of the fault signal, and makes a corresponding tripping action according to the analysis result. The invention also provides a device for preventing the multi-loop same-list-phase fault zero-sequence protection operation refusal and a protection system of a small-resistance groundingsystem. According to the method for preventing the zero-sequence protection operation refusal of the multi-loop same-list phase fault, the problems that the zero-sequence current protection refusal operation of the line is caused by the multi-loop same-list phase fault and finally, the zero-sequence protection override trip of a transformer is caused in a small-resistance grounding mode of a powergrid can be solved.

Description

technical field [0001] The present invention relates to the technical field of relay protection in electric power systems, in particular to a method for preventing zero-sequence protection refusal to operate for multi-circuit lines with the same single-phase fault, a device for preventing zero-sequence protection refusal for multi-circuit lines with the same single-phase fault, and a small resistance grounding system protection system. Background technique [0002] At present, with the increase of cable lines, the urban area is gradually transformed into a small resistance grounding system. The small resistance grounding system cannot run for a long time under the single-phase fault of the line, and needs to quickly trip the faulty line switch through the line zero-sequence current protection after a delay. If the faulty line switch fails to trip, the switch on the side of the transformer should be tripped through the zero-sequence current protection of the transformer on t...

AI Technical Summary

Problems solved by technology

[0007] The present invention provides a method for preventing the zero-sequence protection from refusing to operate due to the same single-phase fault of multiple circuits, a device for preventing zero-sequence protection from refusing to operate due to the same single-phase fault on multiple circuits, and a protection system for a small resistance grounding system, which solves the problems in the related art Existing problem of main transformer zero-sequence protection leapfrog tripping

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