A Model For Surge Distribution Studies on Substation Grounding Grids

This paper describes a new model to analyzes the performance of grounding systems during direct lightning strikes on a power substation. The proposed model uses three different types of multi-conductor transmission lines for representing the substation grounding system, including the substation shielding conductors. The model calculates currents and transient voltages in the aerial and underground structures, including the leakage currents dissipated into the soil. A methodology to calculate the aerial and underground parameters is also included. The model was validated successfully. Computer simulations results show that the inclusion of shielding conductors into the analysis reduce current and voltage magnitudes, leading to a less conservative design.