A novel mathematical model for the lightning response of a grounding system buried in multilayered earth based on the quasi‐static complex image method

SUMMARY A novel mathematical model for accurately computing the lightning currents flowing in the grounding system of a high voltage a.c. substation, buried in multilayered earth, has been developed in this paper. Together with the fast Fourier transform (FFT), the conducting effect of harmonic wave components of these currents and the capacitive and inductive effects from the interface between different soil layers were analysed in the frequency domain. Quasi-static complex image methods and a closed form of Green's function were introduced to accelerate the calculation. With inverse FFT, the model can calculate the distribution of lightning currents in any configuration of the grounding system. This can be used for studying the performance of transient lightning responses to grounding systems. Copyright © 2011 John Wiley & Sons, Ltd.