Route selection method for single-phase grounded malfunction in grounded system of low current

Abstract

A method for selecting wire of single phase earthing fault in small current earthing system measures zero sequence current increment of each circuit at bus side before and after fault and selects wire according to principle that zero sequence current increment of fault circuit is equal to negative value of nonfault circuit zero sequence current increment sum.

Description

Technical field: [0001] The invention relates to a line selection method for a single-phase grounding fault of a small current grounding system applied in a power system. Background technique: [0002] my country's 6-35KV distribution network is generally a small-current grounding system. When a single-phase ground fault occurs, the regulations stipulate that it can continue to run for 12 hours. Grounding becomes a multi-point grounding short circuit. Arcing grounding will also cause overvoltage of the entire system, damage equipment, and destroy the safe operation of the system. Even if arc suppression measures are taken, the faulty line must be found for maintenance, so the faulty line must be found in time. [0003] At present, there are roughly two types of single-phase grounding line selection methods: 1. Line selection methods using ground fault currents, such as zero-sequence current fundamental wave component method, harmonic component method, transient component meth...

AI Technical Summary

Problems solved by technology

The accuracy and reliability of the single-phase ground fault line selection device formed by these line selection methods are not satisfactory in use.

[0004] Using the line selection method of ground fault current, there are three key problems of low line selection accuracy, one is that the power frequency fault current is relatively smaller than the high frequency oscillation fault current; the second is that unbalanced loads also cause zero-sequence current; the third is single-phase grounding The effect of transition resistance when

[0005] The continuous opening and closing of the switch test method will give more impact to the already unstable system. The accident is not ruled out, but it will cause an accident and cause a short-term power outage; the signal injection method is serious due to the different structure and load nature of each system. affect its accuracy

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