Simulation of substation grounding grids with unequal-potential

A method of forming the equation system for simulating substation grounding grids with unequal-potential, i.e., the potential drop caused by the interior resistance of conductors is taken into account, is presented, based on a theory of combination of field and circuit. The equation system with the potential at discretization points of the grid as unknowns is formed by the method of node analysis in the circuit theory, and the definition of the mutual-resistance between conductors located in conducting media concerns with the electric current field theory. The method presented is capable of calculating the grids with arbitrary structure and floating electrodes in multiple-layer earth models. Comparison of calculation results of grids by equal and unequal potential models is given