Wire selection method for power distribution network single phase earthing failure based on transient signal

Abstract

The invention discloses a distribution network single-phase ground fault route selection method based on a transitional quantity signal. The method comprises the following steps: determining the initial time of the fault; the adaptive selection of the characteristic frequency-band; and calculating and comparing the transient zero-sequence current-component amplitude value in the characteristic frequency-band; the invention definitely distinguish the fault line and the healthy line by using the characteristic that the abundant transient high-frequency component is include in the fault current at the moment of occurrence of the single-phase ground fault; and the method can adaptively determine the characteristic frequency-band and perform fault route selection by using the characteristic quantity of the transient zero-sequence current in the characteristic frequency-band, and the success ratio reaches above 99 percent through a great mount of simulation and the field data test, and is far higher than that of the route selection method in the prior art at present. The route selection method can be applied to the fault route selection for the transformer station where the neutral point is not grounded and is not directly grounded.

Description

technical field [0001] The invention belongs to the field of power system distribution network fault detection, and relates to a line selection method for a single-phase ground fault in a distribution network, in particular to a single-phase ground fault line selection method for a distribution network based on a transient quantity signal. Background technique [0002] Most power grids with a voltage level of 66kV and below in my country adopt the neutral point indirect grounding method. When a single-phase ground fault occurs in the power grid under this mode, the fault current is small. Although the regulations allow continuous operation for 1 to 2 hours, the voltage of the non-grounded phase after the fault It becomes the line voltage, which brings hidden dangers and threats to the insulation of the system. It is necessary to cut off the faulty line as soon as possible to avoid two-point grounding and short-circuit accidents. At present, domestic small-current grounding li...

AI Technical Summary

Problems solved by technology

[0014] The purpose of the present invention is to overcome the shortcomings of low line selection accuracy in the prior art, and to provide a method for line selection for single-phase ground faults in distribution networks based on transient signals. When, based on the rich high-frequency transient components contained in the zero-sequence current signal of the fault line, the characteristic frequency band is adaptively determined by extracting the high-frequency transient signal in the zero-sequence current of all protected lines after faults. Compare the transient zero-sequence current characteristics of each line in the frequency band, and further calculate and accurately give fault line selection information

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