Effect of group grounding on the potential rise across solar PV panels during lightning strike

Grounding systems play a vital role for dissipating the energy originating from a lightning stroke to the earth, functioning as an important component for protection and safety. In a solar photovoltaic (PV) farm, solar PV panels are fixed on a grounded structure with bolts and nuts. The structure, the frame of the PV panels, and the bolts and nuts are metallic (together called the assembly) and the layout of all assemblies of the entire solar farm depends on the terrain where they are installed. Lightning protection systems which are installed on a solar PV farm are mostly based on a Franklin rod (connected to a down-conductor) as the preferred point of attachment. These lightning rods can be installed either as isolated systems or as non-isolated systems from the solar panel assemblies. This paper is focused on the effect of group grounding on the potential rise across the solar PV panels during lightning strike. This whole assembly is simulated for various lightning attachment points in PSPICE using the lossy transmission line model. Voltage drop at various points in the assembly is measured for various soil resistivity. Based on the simulation results, group grounding of solar PV panels with middle grounding shows relatively low voltage drops compared to end grounding.