Active grounding protection device of direct-current looped network system and working method thereof

The invention relates to an active grounding protection device of a direct-current looped network system and a working method thereof. The active grounding protection device comprises an isolation unit, a control unit and a sampling unit, wherein the isolation unit is connected between a direct-current bus and a load of the direct-current looped network system; the sampling unit is used for collecting voltages at two ends of the load; the control unit is used for outputting a control signal according to the voltage; and the isolation unit is used for switching to a cut-off state according to the control signal when the direct-current looped network system has a grounding fault, so that the direct-current bus is isolated from the load. When a grounding fault occurs, the control unit drivesthe isolation unit to isolate the direct current bus from the load, so that other branches are prevented from being influenced by a line where the fault occurs, the isolation unit is arranged to reduce distribution of capacit