Abstract: This paper analyzes the characteristics of single-phase grounding fault in neutral power grid, combined with the way of fault monitoring and processing, well as the actual working condition of complex power grid, and elaborates the advantages of the phase control type arc suppression coil and single-phase grounding management system in coupling application complex power grid. The aim is to optimize the system operation mode, improve the reliability of fault management and line selection processing for single-phase grounding fault in complex power grid, perfect the monitoring, line selection and processing functions and technical measures of single-phase fault.