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. The grounding down conductor is the connection part of the power equipment and the grounding grid. During the long-term operation of the power equipment, the connection may be affected by damp and other factors, and the connection point may be rusted or even broken. The resistance of the grounding grid connection point is increased, which cannot meet the requirements of the electric power regulations, so that there are hidden dangers in the operation of the equipment, and in serious cases, the equipment will 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.