Arc light high-resistance grounding fault detection method and device

Abstract

The invention provides an arc light high-resistance grounding fault detection method. The method comprises the following steps: acquiring a sampled zero-sequence voltage sequence f(n) for Fourier transform, obtaining the required third harmonic amplitude U3, fifth harmonic amplitude U5 and fundamental wave amplitude U1, adding the third harmonic content D3 to the fifth harmonic content D5 according to a preset formula to obtain the total harmonic content Hn, and determining that a power distribution system has an arc light high-resistance grounding fault when the total harmonic content Hn of three or more consecutive periods exceeds a setting value P. A detection algorithm is started when the harmonic wave exceeds the limit, a fault line is discriminated according to the correlation between transient zero-sequence currents of lines, the reliability and sensitivity are high; and the fault line with the arc light high-resistance grounding fault can be efficiently and rapidly identified,and the method and device have significance in rapidly recovering stable operation of the power system.

Description

technical field [0001] The invention belongs to the field of relay protection for power system distribution lines, in particular to a method and device for detecting an arc light high-resistance grounding fault. Background technique [0002] In the distribution system with the neutral point grounded through the arc-suppressing coil, due to the many branches of the distribution line, the natural and geographical environment is relatively complex, and high-resistance arcs that are grounded through non-metallic conductive media such as branches, ponds, and grass often occur. Ground fault (transition resistance can reach hundreds or even thousands of ohms). When an arc high-resistance grounding fault occurs, it is usually accompanied by the generation of a high-temperature arc, which is easy to burn the line, ignite the surrounding flammable materials, and cause a fire; the dropped line is a great threat to the life safety of the surrounding staff; the fault lasts for a long tim...

AI Technical Summary

Problems solved by technology

[0003] According to the different fault characteristics used, the existing detection methods can be divided into: steady-state electrical quantity method, transient electrical quantity method, traveling wave component, artificial intelligence method, etc., but the methods at this stage have certain limitations. dead zone or limitation

Compared with the steady-state component, the transient component of the transient method is relatively more significant, but if only the transient method is used, it is often unable to directly deal with arc high-resistance ground faults with significant arc distortion characteristics, and the protection device is prone to misoperation; if only Using the harmonic method, if only based on the zero-sequence voltage harmonic content, the accurate identification of the faulty line cannot be directly realized

The artificial intelligence method is severely limited by the selection of field test data, and its physical meaning is not clear

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