Analysis of Transient Performance of Grounding System Considering Frequency-Dependent Soil Parameters and Ionization

Frequency-domain approaches are usually used to study the impact of the frequency dependence of soil electrical parameters on the lightning response of grounding systems. On the other hand, time-domain simulations are required to study nonlinear soil ionization behavior. A time-domain frequency-dependent simulation is needed to incorporate both effects simultaneously. Based on dynamic harmonic domain (DHD) concept and transmission-line method, this paper derives a new approach for simulating the grounding system surge behavior that includes both time-dependent ionization and frequency-dependent effects of the soil. The DHD permits to decouple harmonic contents of each variable state during transients in time-domain simulation. The simulation results are validated against measured and simulated published results from other researchers. The comparison of experimental results and those provided by this model denoted its consistency.