Analysis of Soil Types and Grid Configurations on Substation Grounding for Safety Design Due to Lightning Strike

Abstract When a substation gets a lightning strike, human or operator may be exposed to touch and step voltage if they are touching equipment or are inside the substation that. Generally, substation grounding is a grid system or a combination of grid and rod to obtain a value of low resistance. Values of touch, and step voltages are important parameters for human safety, which are significantly influenced among, other things by the types of soil and grid configuration. Design a substation grounding, the parameters play an important role. This paper discusses the influence of the soil types and the grid configuration on the safety design under lightning strikes by simulation using ATP draw. The soil structure is homogeneous, and the grid configuration is equipped with ground rods and without ground rods. The IEC standard waveform varies in magnitudes: i.e., 10 kA, 30 kA, and 50 kA are injected into a substation gantry. The results show that types of swamp, clay, and wet sand meet for safety for the lightning current of 10 kA, but for the current larger than 30 kA, the swamp type only meets safety requirements. The configuration with a small amount of ground rod is less significant to improvement for safety.