High resistance earthing fault detection method based on transient traveling wave

Abstract

The invention relates to a method for testing high impedance faults, which is based on transient traveling waves and belongs to the electric system protecting and controlling technique field. The method comprises faults actuating and faults testing, wherein the faults actuating adopts transient traveling waves electric quantity to judge actuating, The faults testing is actuated through comparing the transient traveling waves electric quantity and a threshold value. The fault testing adopts fault components to judge, faults testing results are output through an algorithm of fault detection. Three algorithms are adopted in high-resistance fault judgments, which include a high frequency algorithm, a harmonic algorithm, and a fundamental wave algorithm. The three algorithms can be used in either a single end form or in combination to judge high-resistance actuating. The method can test thoroughly each main frequency band information which may be produced when high resistance faults occur.

Description

technical field [0001] The invention belongs to the technical field of power system protection and control, in particular to distribution line protection and fault detection. Background technique [0002] Definition of high-resistance ground fault: Abnormal operating conditions in which harmful contact occurs between current-carrying conductors (including overhead wires, cables, etc.) and some non-metallic conductive media such as roads, soil, branches or cement buildings in power systems . Because the electrical characteristics of the medium itself limit the size of the fault current, traditional protection devices, such as overcurrent protection, cannot be detected correctly. [0003] General short-circuit faults will cause large current and voltage changes, and traditional relay protection equipment in power distribution systems mostly focus on these obvious power frequency current and voltage quantities. However, a considerable part of the distribution system faults ar...

AI Technical Summary

Problems solved by technology

[0004] At present, there are mainly the following methods for high-impedance fault detection: 1) Because the nonlinearity of transition resistance will introduce harmonics, the method of detecting high-impedance faults is formed by using the third harmonic in the system current and the phase of the harmonics relative to the system voltage. However, the sensitivity of the method is insufficient due to the large number of background harmonics inherent in the distribution system, which can interfere greatly with the method, and the third harmonic is not the only definitive feature that can identify high-resistance faults , the reliability of the method is also affected by

2) Because high-impedance fault arcs will generate high-frequency noise, a method of using the absolute value of the sampled value change to detect high-frequency disturbances caused by high-impedance faults is proposed, but high-frequency noise is not the only problem that only high-impedance faults have characteristics, some load equipment will also generate high-frequency noise, so the reliability of this method is low

3) It is difficult to accurately and reliably detect high-resistance faults based on the detection of a single electrical quantity, and proposed fault detection methods based on artificial intelligence technologies such as expert systems and neural networks, but these methods are very complicated in organization, and many criterion principles come from experiments and experience

Moreover, such methods do not propose the significant characteristics of high-resistance faults and normal operating conditions in principle, so they cannot fundamentally solve the problem of high-resistance fault detection

Images