Three-core cable fault location method based on double-end asynchronous measurement

Abstract

A three-core cable fault distance measurement method based on double-end asynchronous measurement comprises the following steps: firstly, calculating a synchronous measurement error phase angle by using cable core current, voltage and grounding wire current phasors measured at the head end and the tail end of a line before a fault occurs; secondly, by means of phasors obtained after phase correction of line head end measurement and tail end measurement after the fault occurs, conducting core-shielding layer voltage and voltage to ground at the virtual fault point and phase currents before and after the fault point are calculated respectively; then estimating resistance between the conductor core and the shielding layer at a virtual fault point by using the obtained conductor core-shielding layer voltage and the calculated fault current, and further determining a fault phase by comparing three-phase fault resistance; and finally, determining the accurate position of the fault by searching the minimum difference value of the voltage to ground of the virtual fault point calculated by the phasors at the head end and the tail end. The method can accurately estimate the phase angle of the synchronous measurement error at the two ends of the three-core cable line, identifies the fault phase and the accurate fault position under different fault conditions, and has high engineering application value.

Description

technical field [0001] The invention relates to the field of power grid equipment, in particular to a three-core cable fault location method based on double-ended asynchronous measurement. Background technique [0002] The urban 10kV distribution network mostly uses three-core cable lines, which have the advantages of occupying less land area, not easily affected by bad weather, safer for people, and not affecting the beauty of the environment. Most of the three-core cable lines are laid underground, and it is difficult to troubleshoot. Therefore, the fault location of the three-core cable line is of great significance for improving the fault perception level of the distribution network cable, improving the work efficiency of the inspection personnel, and ensuring the safe and stable operation of the distribution network. [0003] At present, the fault location methods for cable lines can be mainly divided into two categories: traveling wave method and impedance method. Th...

AI Technical Summary

Problems solved by technology

Most of the three-core cable lines are laid underground, and it is difficult to troubleshoot

[0004] Different from single-core cables, the structure of three-core cables is complex, and there is strong electromagnetic coupling between the three-phase conductors and the metal shielding layer. The fault location methods proposed by existing research cannot be applied to this complex situation. Structure Proposes Effective Fault Location Method

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