FDTD transient analysis of grounding grids a comparison of two different thin wire models

A thin wire model for FDTD simulations is proposed for the study of transient potential rises and currents in a grounding grid. The model is an extension of the formalism of Holland, and it is compared with the thin wire model of Baba, Nagaoka, and Ametani, using a case study previously validated with measurements. Special interest is drawn on the computation of the potential close to the surface of conductors. To do so, an approximated formula based on the previous work of Noda and Yokoyama is proposed. The results are compared in terms of transient potential rises and currents in a grounding grid. The comparisons are in good agreement.