Study on the Corrosion of Grounding Devices in Power System after Lightning Strike

Because of the differences in temperature, humidity and pH value of the soil where the grounding grids located, the corrosion of the grounding grids is different, resulting in a large range of the grounding resistance. The severely corroded grounding grids will generate extremely high residual voltage after lightning strike and lead to the increase of ground potential near the electrical equipment and causes safety hazard to people and electrical equipment. Lightning impulse current also accelerates the corrosion of the grounding grids. In order to further grasp the influence of lightning on the corrosion of the grounding grids, the change law of the corrosion under lighting impulse current and power frequency current is analyzed in this paper. It is found that both lightning current and power frequency current have influence on the corrosion of the grounding grids through theoretical analysis and experiments. According to the conditions of chemical reaction, the electrical charge acts as a catalyst. Compared with a large number of electrical charges left by power frequency current, lightning impulse current leaves a small amount of it because of the extremely short treatment time. Therefore, lightning impulse current has more severe impact in the long term.