The reliable and effective connection between the grounding down conductor of the power equipment and the ground network is the fundamental guarantee for the safe operation of the equipment. During the long-term operation of power equipment, the connection of the ground down conductor may be affected by moisture and other factors, and the connection point may be corroded or even broken, which may increase the resistance of the connection point between the ground down conductor and the main grounding grid, and thus cannot Meet the requirements of electric power regulations, so that there are potential safety hazards in the operation of the equipment, and in serious cases, it will cause the equipment to lose ground. Therefore, in the "Twenty-Five Key Requirements to Prevent Major Accidents in Electric Power Production", it is clearly stated that the continuity test of the down conductor of the grounding device should be carried out once a year.