A method and system for locating fault sections in distribution network based on ground fault transfer

Abstract

The invention discloses a method and system for locating a distribution network fault section based on ground fault transfer. When an arc ground fault occurs in a neutral point non-effectively grounded system, the active grounding of the faulty phase bus can effectively suppress the arc overvoltage and eliminate the arc. Fault. At the same time, the zero-mode current polarity of the upstream measuring point of the fault point is opposite before and after the fault transfer, and the zero-mode current polarity of the downstream measuring point of the fault point is the same, which can identify the fault section. S-transform the zero-mode current of each measuring point after each feeder is grounded twice, determine the arrival time of the first wave head of the fault traveling wave according to the principle of modulus maximum at the Nyquist frequency, and calculate the corresponding phase at this time, Then the polarity coefficient of each measuring point is obtained; the section coefficient is constructed by the product of the polarity coefficients of the measuring points at both ends of the section to realize the location of the fault section. This method can avoid misjudgment of faults caused by asynchronous data collection, and is not affected by the reverse polarity of zero-sequence CT, which improves the reliability of fault section location in distribution network.

Description

technical field [0001] The invention belongs to the technical field of distribution network fault section positioning, and more specifically relates to a distribution network fault section positioning method and system based on grounding fault transfer. Background technique [0002] The medium and low voltage distribution network in my country generally adopts the non-effective neutral point grounding method, which has complex structure, wide distribution area, harsh operating environment, and frequent random faults. When a single-phase instantaneous ground fault occurs, an arc overvoltage is likely to occur. If it is not dealt with in time, it will cause the accident to expand, cause a trip and blackout, and destroy the continuity of power supply. At the same time, in order to reduce the difficulty of manual line inspection and effectively reduce the scope of fault location, efficient and accurate identification of fault sections plays an important role in quickly restoring...

AI Technical Summary

Problems solved by technology

[0005] In view of the defects and improvement needs of the existing methods, the purpose of the present invention is to propose a distribution network fault section location method and system based on ground fault transfer, aiming at solving the fault section location of the distribution line after the transfer grounding device is put into use question

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