Power distribution line grounding fault property identification and recovery method

Abstract

The invention relates to a power distribution line grounding fault property identification and recovery method, which comprises the following steps of: after a power distribution line grounding fault occurs, overlapping a certain phase before power transmission of a power distribution line; collecting the voltage and current waveforms of the overlapped phase, and filtering; calculating derivatives of the voltage and the current; constructing a least square method identification capacitance model, and solving the capacitance under the least square meaning; calculating a model error EC (k) of the capacitance model; constructing a least square method identification resistance-inductance model, and solving resistance and inductance under the least square meaning; and calculating a model error EZ (k) of the resistance-inductance model, wherein when EZ (k) is less than krelEC (k), the fault is a permanent grounding fault, otherwise, the fault is an instantaneous grounding fault. According to the invention, no additional device is needed, and the fault property can be determined only by overlapping a certain phase and detecting the current and voltage values of the overlapped phase; and the ground fault property identification method is simple, efficient and low in cost.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method for identifying and restoring the nature of a distribution line grounding fault. Background technique [0002] According to the statistics of actual operation data, most of the faults in the overhead lines of the distribution network are instantaneous ground faults, and the cables also have a certain proportion of instantaneous ground faults. When the switch can distinguish between permanent and transient ground faults before reclosing, it can effectively reduce the impact on the system and the switch after reclosing the fault. In addition, when used in conjunction with feeder automation, it can also effectively reduce fault handling time, thereby improving power supply reliability. [0003] The existing distribution network switches are all three-phase integrated switches. When tripping, the three phases are disconnected at the same time....

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problem of discriminating the nature of the ground fault of the distribution line, the present invention provides a method for identifying and recovering the nature of the ground fault of the distribution line. The discrimination of the nature of the ground fault is realized by detecting and overlapping a certain phase before the power transmission of the power outage line. The discrimination method is simple and reliable without additional equipment

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