Fault line selection system for single phase ground fault in low current grounded system

Abstract

The invention provides a fault line selection system for a single phase ground fault in a low current grounded system. The fault line selection system involves that: a sampling unit completes the operation of single acquisition and algorithm processing, etc, and a man-machine unit is mainly responsible for displaying a man-machine interface and bulk memory storing, and an acquisition unit and the man-machine unit exchange information through an ARM board. The sampling unit has the advantages of strong capability of data processing, capability of processing large amount of data, and capability of fast real-time processing, etc, and thus a high-precision data acquisition system is constituted, and the acquisition precision and the acquisition speed are increased. The mutual connection among the sampling unit and the general-purpose ARM board and the man-machine unit enables the apparatus to work in an efficient and reliable manner. At the same time, the sampling unit, the ARM board and the man-machine unit also work independently and perform processing work individually. A photoelectric coupled isolate circuit which is also provided in the apparatus increases the flexibility and anti-interference of the apparatus. According to the invention, the apparatus increases the accuracy of determining a line grounding fault, shortens the time for fault inquiry, reduces daily maintenance work loads of distribution network lines, increases work efficiency and guarantees the reliable operation of the distribution network system.

Description

technical field [0001] The invention relates to the field of power systems, in particular to a line selection system for a single-phase ground fault line of a small current grounding system. Background technique [0002] In recent years, with the decline of cable application costs and the needs of urban power grid transformation and urban beautification projects, a large number of cables are used in the distribution network, resulting in a rapid increase in the distributed capacitance and distributed conductance of the distribution network, so that when a single-phase ground fault occurs When the grounding zero-sequence capacitor current is large, long-term operation is prone to two-point grounding or multi-point grounding short circuit. At the same time, the arc grounding process will also cause overvoltage in the whole system, which will damage the equipment and destroy the safe operation of the system. When the grounding capacitive current of the distribution network grea...

AI Technical Summary

Problems solved by technology

When a fault occurs in the cable line in the distribution network, the amplitude of the high-frequency component in the fault zero-sequence current is too large, and some existing line selection devices cannot correctly identify the fault line

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