Lightning Transient Impulse Problem of Substation Grounding Grid in Multilayer Horizontal Layered Soil Considering Soil Ionization Effect and Frequency Characteristics

This study proposes a novel mathematical model based on time-domain Garlerkin's boundary element method. Our approach accurately computes the lightning current distribution and lightning current impulse response of buried grounding grid conductors in horizontal multilayered soil, accounting for soil ionization effects and electrical parameter frequency characteristics. To enhance computational efficiency, we integrate the quasi-static complex image method and its time-domain Green's function closed form into the model. An analytical method is employed to compute the mutual inductance coefficient between the branch currents of any two conductor segments and the mutual resistance between the leakage currents. The proposed Galerkin boundary element method simulates the lightning transient impulse response of substation grounding grids in multilayer horizontal soil.