Simulation test study on high resistance grounding fault of broken line under sandy soil conditions in forest and pastoral areas

Abstract

The cable runs through the forest and is deeply buried underground. The operation environment is very complex. If the cable fails to be quickly diagnosed and checked after failure, it will seriously interfere with the safety of distribution network operation in forest and pastoral areas. The existing research results mainly focus on the qualitative theoretical analysis of cable disconnection fault, and lack of fault mechanism research and experimental verification. A hybrid line composed of 5.5km overhead line and 5.5km cable was built in the 10kV distribution network prototype laboratory to simulate the process of high resistance grounding fault and arcing combustion in the real forest and pastoral area distribution network after cable disconnection in contact with sandy ground, and the change of ground transition resistance after high resistance grounding fault was mainly studied. The research results reveal that the initial stage of grounding fault is intermittent arc high resistance grounding fault, then develops into stable arc high resistance grounding fault, and finally becomes permanent small resistance grounding fault. The research results of this paper provide guidance for the detection and protection of cable line fault in distribution network in forestry and pastoral areas.