(1) Human causes, due to the staff operation error or poor daily maintenance, the main phenomena are: the protective insulation layer of the electrical line, the edge of the electrical line is flooded or seriously damp, the equipment in operation or staff maintenance metal parts fall in the wire terminal;

(2) The faults caused by the defects of the equipment itself, such as the poor quality of the factory equipment, mainly focus on poor insulation or insulation damage, equipment insulation aging, material deterioration. 1) Fault symptoms. The symptoms of short circuit fault are obvious, such as large current, burning of fuse, action of protective appliances (thermal relay, current relay), and abnormal operation of related equipment. Serious short circuit fault can cause the burning of line edge or transformer coil, the burning of contactor and the sintering of contacts. 2) Fault cause. (1) When the windlass is running, the load fluctuates and fluctuates unsteadily, resulting in overload operation; (2) Improper operation by anchoring machine operators; (3) Line aging, equipment aging and quality failure in the anchor machine gas control box.