FDTD simulation of a horizontal grounding electrode and modeling of its equivalent circuit

Transient responses of a horizontal grounding electrode in three different arrangements of a current lead wire and a voltage reference wire are calculated using the finite-difference time-domain (FDTD) method for solving Maxwell's equations. The test arrangement does not significantly influence the transient response of the horizontal grounding electrode. The transient response calculated using the electromagnetic transients program (EMTP) for Sunde's equivalent circuit agrees reasonably well with the corresponding response calculated using the FDTD method, except for the initial rising portion of the voltage at the close end (to the excitation point) of the horizontal grounding electrode. The EMTP-calculated response for an equivalent circuit, modified to improve this discrepancy, agrees better with the corresponding FDTD-calculated response.