The RBF-FDTD Method for Computing Lightning-Transient Voltages on Grounding Systems

This paper introduces an advanced application of the Radial Basis Function–Finite-Difference Time-Domain (RBF-FDTD) method, as proposed in [1], for computing lightning-induced transient voltages in grounding systems. The approach models grounding structures as non-uniform transmission lines, governed by telegrapher’s equations with space- and time-varying parameters—inductance <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L(x, t)</i>, conductance <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G(x, t)</i>, and capacitance <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C(x, t)</i>—while accounting for electromagnetic coupling across complex grounding configurations. Leveraging the method’s inherent flexibility and precision, extensive numerical simulations were conducted on two horizontal grounding electrodes and three benchmark grounding grids, validating its capability to accurately capture both localized and distributed transient effects. The results underscore the robustness, computational efficiency, and practical utility of RBF-FDTD in analyzing transient electromagnetic phenomena in power system grounding infrastructures. This study not only confirms the method’s superiority in modeling intricate grounding responses but also offers critical insights for enhancing the design and optimization of grounding systems under lightning and fast-transient conditions.