Small current grounding line selection device and control method of voltage disturbance locked line selection

The invention discloses a small current grounding line selection device of voltage disturbance locked line selection. Hardware is composed of an alternating-current sampling module, a signal output module, a man-machine interaction module, a central processing module and a power supply module; a software function module comprises a voltage disturbance detection part and a line selection processing part; the voltage disturbance detection part is used for judging the disturbance type when a disturbance is happened on a system; and the line selection processing part is used for carrying out related fault line selection processing after a single-phase grounding fault is produced on the system. According to the small current grounding line selection device, single-phase grounding and voltage disturbance can be effectively distinguished, so that a false action cannot be generated in the occurrence of the voltage disturbance and a rejecting action cannot be produced in the occurrence of the single-phase grounding.