A fault monitoring method for substation cable outlets based on initial traveling waves of voltage and current

Abstract

The invention discloses a substation cable outgoing line fault monitoring method based on voltage and current initial row waves. The method includes the following steps that a substation cable outgoing line fault simulation model is built according to the substation cable outgoing line and a network distribution model; the bus voltage and outgoing line three-phase current initial row waves are obtained through a voltage transformer and a current transformer; the fault phases are determined according to the obtained three-phase bus voltage; the polarities of the current initial row waves of all the outgoing line fault phases are compared, and the outgoing line opposite to other outgoing lines in polarity is the fault line. According to the substation cable outgoing line fault monitoring method, the fault phases are judged through the bus voltage generated after the system single-phase earth fault, the polarities of the current initial row waves of all the outgoing line fault phases are compared, and thus the fault line is determined; line selection of the substation cable outgoing lines and distribution lines is achieved, and the problem that it is difficult to conduct line select for current small current earth systems is solved.

Description

technical field [0001] The invention relates to a fault monitoring method for a cable outlet of a substation, in particular to a fault monitoring method for a cable outlet of a substation based on initial traveling waves of voltage and current, and belongs to the technical field of cable fault line selection. Background technique [0002] The neutral point ineffective grounding method is widely used in my country's distribution network. This grounding method has the advantages of high power supply reliability, and its single-phase grounding fault has the highest incidence rate. When a single-phase ground fault occurs, the non-fault phase voltage rises to 1.732 times of the original. In some cases, the ground capacitive current may cause an arc to fly over the fault point, and an overvoltage 4-5 times greater than the phase voltage appears instantaneously, resulting in insulation Breakdown, further expanded into two or more points grounding short circuit; the arc at the fault...

AI Technical Summary

Problems solved by technology

[0006] In order to overcome the above-mentioned deficiencies in the prior art, the present invention provides a method for monitoring faults of substation cable outlets based on initial traveling waves of voltage and current, which can solve the problem of difficult line selection in the current low-current grounding system, and effectively realize substation cable outlets. Fault line selection of its distribution lines

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