Abstract: In this article studies the misjudgment of two sets of MXJD single-phase grounding fault management systems in parallel operation when a single-phase grounding fault occurs in a 10 kV power system of a chemical enterprise. By exploring the phenomena, causes, impacts, and handling processes of this case, the working principle, system design, data sharing, and other key parameters of the MXJD single-phase grounding fault management system are analyzed. Some suggestions for the parallel operation of the single-phase grounding fault management system are proposed, providing reference for the reliable operation of the power grid.