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

In this paper, the ground potential rise (GPR) phenomenon caused by lightning current injected into a field-shaped artificial grounding grid and the potential difference between different two nodes at the edge of the ground grid are observed and analyzed under the artificially triggered lightning. Based on circuit theory and measured current data, a π equivalent circuit is established to simulate the transient response of the grounding grid. The 19 return strokes (RSes) of three artificially triggered lightning were analyzed. The peak currents in the 19 return strokes range from −6.7 kA to −25.1 kA, and the mean value is −14.3 kA. The GPR decreased rapidly and formed a sub-peak after reaching the initial peak. Where the mean value of the initial peak is -148.65 kV and the mean value of the sub-peak is -92.87 kV. The GPR induced by the triggered lightning currents all showed sub-peak phenomena. The sub-peak phenomenon was found to be related to the localized corrosion of the vertical grounding electrode through simulation. Potential difference at the grounding grid edge represents a multi-pulse waveform with alternating polarity dominated by the positive pulse. The peak values of both positive and negative polarity pulses exhibit a gradual decrease, with the first positive pulse displaying significantly higher intensity compared to the subsequent pulses.