Characteristics and Simulation Analysis of Ground Potential Waveform under Artificially Triggered Lightning

In this study, the ground potential rise (GPR) phenomenon caused by a lightning current injected into a field-shaped artificial grounding grid, as well as the potential difference between two different nodes at the edge of the grounding grid, was observed and analyzed under artificially triggered lightning conditions. Based on circuit theory and measured current data, a π-equivalent circuit was established to simulate the transient response of the grounding grid. Nineteen return strokes from three artificially triggered lightning events were analyzed. The peak currents of the 19 return strokes range from −6.7 to −25.1 kA, and the mean value was −14.3 kA. The GPR decreased rapidly and formed a subpeak after reaching the initial peak, with the mean value of the initial peak being −148.65 kV and the mean value of the subpeak being −92.87 kV. The GPR induced by the triggered lightning currents exhibited a subpeak phenomenon. Simulation results indicate that the subpeak phenomenon is related to localized corrosion of the vertical grounding electrode. The potential difference at the grounding grid edge exhibited a multi-pulse waveform with alternating polarity, dominated by positive pulses. The peak values of both the positive and negative polarity pulses gradually decreased, with the first positive pulse displaying a significantly higher intensity than that of subsequent pulses.