Distribution Network Hybrid Grounding Operation Analysis

There is a situation of low resistance grounding systems and arc extinction coil grounding systems mixed operation in the process of substation reconstruction.It is the purpose of the paper that the influence on protection and improvement of hybrid grounding system over separate grounding system are researched.This paper show theoretical analysis of single phase to ground fault in distribution network.With substation practical parameters as the basis,a hybrid grounding model was established to make single phase-to-ground fault simulation.A comparative analysis about separate grounding and hybrid grounding system is carried on.The earth-fault of arc extinction coil grounding will cause the protection false operation in low resistance grounding system.Finally,the paper put forward the effective improvement methods of the zero-sequence current protection in hybrid grounding system.The paper has a high engineering application value.