Ground fault positioning method and device based on zero sequence mutation method and vector method

Abstract

The invention discloses a ground fault positioning method and device based on a zero sequence mutation method and a vector method. The device comprises an overhead current acquisition unit, a data merging communication unit and an upper computer device; the overhead current acquisition unit is connected with the data merging communication unit via a 2.4G communication circuit; and the data merging communication unit is connected with the upper computer device via a GPRS (General Packet Radio Service) module. According to the ground fault positioning device based on a zero sequence mutation method and a vector method, the current acquisition unit with phases A, B and C at different program addresses are adopted and divided into A, B and C phase acquisition indication units, and the non-three-phase program addresses are consistent, so that the acquired current information carries an amplitude parameter and a phase angle parameter, the judgment probability of ground faults of a low current grounding system can be improved, faults can be judged more accurately, and the fault judgment probability can be improved; and the requirements of different grounding systems are met by adopting a fault judgment mechanism combining the zero sequence mutation method and the vector method.

Description

technical field [0001] The invention relates to a method for locating a small current ground fault, in particular to a method for locating a ground fault based on a zero-sequence mutation method and a vector method. Background technique [0002] The wiring of the medium voltage distribution network is complex, with many branches, and most of the line faults are single-phase ground faults. Most of my country's medium voltage distribution network adopts the neutral point through the arc suppression coil grounding system and the neutral point ungrounded system. These two grounded distribution network systems are also called small current grounding systems. After a single-phase ground fault occurs in a low-current grounding system, no short-circuit loop will be formed, and only a small grounding current will be caused by the distributed capacitance of the system. The three-phase line voltage will continue to maintain symmetry, and the system can run live for 1-2 hours. Due to ...

AI Technical Summary

Problems solved by technology

Although the injection system can adapt to different grounding systems, this method fails in power grids with dry climate, large transition resistance and many branches

And the use of signal PT may introduce harmonics to endanger the grid system

The fault location system of the injection method is expensive and increases operating costs

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