Consideration of Generating Mechanism of the Overvoltage between the Ground Wires in a Building Struck Directly by Lightning

Abstract

We investigated the mechanism by which a lightning strike generates overvoltage at a building's distribution board. We analyzed the overvoltage using VSTL electromagnetic analysis software and constructed a simplified mathematical model for calculating the overvoltage. The results confirmed that the overvoltage generated at the distribution board is not affected by the arrangement of the ground wires. The overvoltage is instead dominated by the potential difference between the ground electrodes, which is determined by the potential distribution in the surrounding ground. The overvoltage was calculated by the potential interferometry at steady state of the ground potential distribution. The calculated results of the overvoltages differed within ±10% from the analyzed results.