A method, device and system for locating arc ground fault section in distribution network

Abstract

The invention discloses a method, device and system for locating an arc grounding fault section of a distribution network. First, the zero-sequence current sudden change is used to determine the fault time, and the 2nd, 3rd, 4th and 5th working hours after the fault starting time are calculated respectively. The four weighted Euclidean distances between the zero-sequence current signal and the fundamental frequency sine wave of the frequency period, the maximum value is recorded as the weighted Euclidean distance of the fault signal; when the weighted Euclidean distance of the fault signal is greater than the set threshold at a certain time, it is determined as An arc fault has occurred; then, take the zero-sequence current of all segments one power frequency cycle after the start of the arc fault, use S transform to perform energy spectrum analysis on the zero-sequence current of this cycle, determine the main resonant frequency of each segment, and then determine Characteristic frequency band; finally, compare the energy values ​​of characteristic frequency bands of each section, and determine that the section with the largest energy is the fault section. The invention solves the problem of arc grounding fault section location, and the effectiveness is not affected by the grounding mode of the distribution network, the initial phase angle of the fault and the fault position.

Description

technical field [0001] The invention belongs to the technical field of power grid fault location, and in particular relates to a method, device and system for locating an arc grounding fault section of a distribution network. Background technique [0002] According to statistics, more than 80% of power outage accidents in my country are caused by distribution network faults. Distribution network faults are mainly single-phase grounding faults. Among single-phase grounding faults, arc grounding faults are the most common. With the increasing complexity of the urban distribution network, cable lines are widely used. Because the distributed capacitance of cable lines is much larger than that of overhead lines, the capacitance current of the system to ground increases gradually. In addition, the structure of the cable is protected by multiple layers of insulation, shielding and armoring. In addition to the rigid damage of the cable caused by external force damage, the cable line...

AI Technical Summary

Problems solved by technology

In addition, there are multiple layers of insulation, shielding and armor protection in the structure of the cable. Except for the hard damage of the cable caused by external force damage, the fault of the cable line usually manifests as an arc fault. At this time, affected by the capacitive current, the arc is often difficult to Reliable extinguishing

[0003] The operating environment of the actual distribution network is poor, maintenance is difficult, and various types of faults are inevitable. Especially when an arc ground fault occurs, the high temperature of the arc will cause insulation damage, and the arc overvoltage will further aggravate the breakdown of the insulation. Single-phase ground faults can easily evolve into two-phase short-circuit or even more serious accidents, which seriously threaten the safety and reliability of power supply in the distribution network

Images