A method of line selection for single-phase grounding fault in small current grounding system

Abstract

The present invention provides a small current grounding system single-phase grounding fault line selection method which comprises the steps of (1) building a power distribution network single-phase grounding fault line selection criterion set P, (2) analyzing the confidence level G corresponding to the line selection criterion in the criterion set P, (3) obtaining the fault characteristic of a single-phase grounding fault, (4) calculating the fault measure H of all power distribution network feeders corresponding to the line selection criterion according to the fault characteristic, and (5) determining a fault feeder. Compared with the prior art, the invention provides the small current grounding system single-phase grounding fault line selection method, the condition that a local fault characteristic is easily interfered by an environment and is affected by the precision of a measuring device is avoided, the problem of low credibility of single diagnostic criterion conclusion is overcome, the reliability and universality of the single-phase grounding fault line selection method are improved, and the method has a practical value.

Description

technical field [0001] The invention relates to the field of power systems, in particular to a line selection method for single-phase grounding faults in a small current grounding system. Background technique [0002] The distribution network mostly adopts the low-current grounding method, and the single-phase ground fault is one of the faults with the highest frequency. Since the neutral point is not directly grounded, the impedance value of the fault path formed by a single-phase ground fault is relatively large, and the fault symptoms caused by it are not obvious. Although the existing single-phase-to-ground fault line selection method for small-current grounding systems has undergone long-term and extensive research, there are still deficiencies in reliability and universality. [0003] The single-phase-to-ground fault in the distribution network causes a weak change in electrical quantity, which usually does not lead to protection action, and the unbalanced operation p...

AI Technical Summary

Problems solved by technology

However, in addition to the fault signal, there are also other types of signals mixed in the transient quantity, and it is easy to cause misjudgment if it is directly applied

[0005] In summary, the existing single-phase ground fault line selection methods are mostly based on local fault characterization, and a single criterion is used for diagnosis. Therefore, it is necessary to provide a single-phase ground fault line selection method for small current grounded systems that can adapt to various power grid operating conditions

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