Effect of Soil Moisture on Arc Discharge in Sandy Soils Under Lightning Struck

Onset electric field of arc discharge in soil is one of the basic parameters to analyze the lightning impulse performance of a grounding device. In this letter, a grounding rod is placed on the axis of a cylinder filled with sand, and an impulse current is applied between the grounding rod and the cylinder to simulate the electric field around the grounding rod under lightning strike. The transient current and potential are measured simultaneously with which, the onset electric field of arc discharge in sandy soils with different humidity and the time of discharge delay is obtained. Then, the effect and mechanism of the soil moisture on the arc discharge is discussed.