Power distribution network single-phase earth fault identification and information fusion line selection method and system

Abstract

The invention discloses a power distribution network single-phase earth fault identification and information fusion line selection method and system. The method comprises the following steps: collecting a zero-sequence current signal I0i and a zero-sequence voltage UN of each branch; performing feature extraction processing on the zero-sequence current signal I0i and the zero-sequence voltage UN signal of each branch; calculating and recording a single fault degree mi according to the extracted features; calculating multiple fault degrees mn according to the calculated single fault degree mi; judging whether the zero-sequence voltage acquired by the zero-sequence voltage transformer is greater than a threshold value delta or not by utilizing the multiple fault degrees mn; when the zero-sequence voltage is greater than a threshold value delta, starting all-time recording, uploading fault waveform data acquired by all-time recording to a fault waveform database, and determining a fault line; and reporting a fault line, and completing single-phase earth fault identification and information fusion line selection of the power distribution network. According to the method, fault data as much as possible in the continuous process of the single-phase earth fault is fused, the single-time fault degree and the continuous fault degree are calculated, and the most reliable line selection result is obtained.

Description

technical field [0001] The invention belongs to the technical field of power distribution, and in particular relates to a method and system for single-phase grounding fault identification and information fusion line selection of a power distribution network. Background technique [0002] Single-phase grounding fault is a common type of fault in distribution network. According to relevant statistics, in a recent six years, there have been 1553 single-phase grounding faults in a certain city distribution network alone, one third of which are caused by cables and other equipment. The lead is triggered, and it is increasing year by year, causing serious harm. Therefore, it is urgent to complete the line selection and troubleshoot as soon as possible. In general applications, most distribution networks use arc suppression coils to limit the grounding current. This type of distribution network system is also called a resonant grounding system. In this type of resonant grounding s...

AI Technical Summary

Problems solved by technology

The root of this kind of phenomenon is that the fault criterion of typical line selection devices is single, and it is easily disturbed by complex working conditions such as load switching in the system, which makes the line selection results distorted or unsuccessful.

For the high-resistance fault section where the reliability problem is concentrated, because the zero-sequence current characteristics are not obvious or the amplitude of the zero-sequence current change is too small, the fault zero-sequence characteristics are submerged in the zero-sequence current noise generated by the normal operation of the line. Distinguishing, and limited by the traditional method, the judgment of the fault line is often based on the characteristics of a single zero-sequence voltage and zero-sequence current when the fault line occurs, which makes the timing of the line selection program uncontrollable, further aggravating the risk of signal interference, so Typical line selection methods in high-resistance fault sections often cannot make reliable decisions

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