Impulse Efficient Optimum Impedance Grounding Electrode Configuration for Lightning Transients

As the simple grounding electrodes alone may not provide the required low impedance beyond the effective length, a new electrode configuration of optimum impedance is proposed for lightning transients. The proposed grounding electrode configuration comprises a primary vertical electrode connected with the optimum count of horizontal enhancement electrodes. Exhaustive impulse test simulations are carried out on the primary electrode integrated with multiple enhancement electrodes whose effective lengths are estimated in previous research works. From the simulations, the effective count of enhancements (ECEs) is determined by an optimum impedance reduction approach to arrive at an impulse-efficient electrode configuration. The proposed electrode configurations' resistances and impedances are computed to obtain the impulse coefficients. The reductions of impedances and impulse coefficients in the proposed electrode configurations are calculated. An empirical expression is derived to estimate the ECE using numerical methods. The proposed electrode configura-tion and the ECE expression are verified with the field experiments.