Numerical calculation of grounding system in low-frequency domain based on the boundary element method

A new mathematical model for accurately computing currents flowing along the high-voltage ac substation’s grounding system and nearby floating metallic conductors buried in the multilayer earth model has been developed in this paper, which is a hybrid of the Galerkin-type boundary element method (BEM) and the conventional nodal analysis method. Only the propagation effect of electromagnetic waves within the substation’s limited area has been neglected in this model. The quasi-static complex image method and the closed form of Green’s function are introduced into this model to accelerate the mutual impedance and induction coefficients calculation. The model is then implemented in a computer program, which can be used to calculate current distribution of any configuration of the grounding system, with or without floating metallic conductors’. Copyright q 2007 John Wiley & Sons, Ltd