Power distribution network single-phase disconnection fault protection method and system thereof

Abstract

The invention discloses a power distribution network single-phase disconnection fault protection method and a system thereof. The method comprises the following steps: acquiring three-phase current of each outgoing line of a transformer substation; extracting a fundamental wave vector of the three-phase current by using FFT; calculating the break variable of the three-phase current amplitude by using the fundamental wave vector; if the break variables of the three-phase current amplitudes are all smaller than 0, starting protection; after protection is started, sequencing the absolute values of the three-phase current amplitude break variables, and respectively calculating the ratio lambda of the maximum phase of the absolute values of the three-phase current amplitude break variables to the load current before the fault and the phase difference beta of the minimum absolute values of the break variables and the intermediate phase current; and judging whether the line has a broken line high-resistance fault or not according to lambda and beta, when conditions are met, determining that the fault occurs in the line, otherwise, determining that the fault does not occur in the line, and when it is determined that the fault occurs in the line, performing fault protection. The method can be fused with in-station current protection to realize quick isolation of a broken line fault, and the broken line fault can be isolated in a minimum range through a time range matching method.

Description

technical field [0001] The invention belongs to the technical field of relay protection, and in particular relates to a single-phase disconnection fault protection method and system of a distribution network. Background technique [0002] At present, the overhead lines of my country's distribution network are basically insulated, causing lightning strikes and disconnection faults to occur from time to time. Overvoltage, motor damage, personal injury and other accidents will occur after disconnection fault, so it has attracted people's attention in recent years. [0003] At present, the treatment of disconnection faults mainly includes centralized line selection in the station, and section positioning and isolation based on feeder automation technology outside the station. Line selection in the station is generally realized by positive sequence current mutation or negative sequence current, while the current ground fault The line selection device mainly uses zero-sequence vo...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a single-phase disconnection fault protection method and system for the distribution network in view of the above-mentioned deficiencies in the prior art. Isolation Problems in Three Forms of Grounding

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