Influence of electrode geometry and ground parameters on transient grounding impedance for small lightning current

In this paper the transient ground impedance characteristics are discussed when the shape of the ground electrode and the electrical characteristics of the ground, namely the ground resistivity and the permittivity, are varied. The analysis is carried out through the FDTD method. The transient ground impedance estimated by the FDTD method is verified by comparison with experimental results by a model experiment. As a result, it was found that the factor that dominates the transient ground impedance varies depending on the time from the injection of the current.