Enhanced Circuit-Theory-Based Model for Accurate Simulation of Electrically Large Grounding Systems

Accurate modeling of grounding systems is crucial in various power systems applications, notably in substation and transmission line groundings. This study introduces a computationally efficient approach for the accurate modeling of diverse grounding grids, incorporating conductor losses in the calculations of leakage current distribution. The paper highlights the limitations of classical equipotential models through simulations, especially in complex, large-scale grounding systems. It quantitatively establishes the conductor length threshold from which the equipotential assumption causes significant deviations from a more accurate model, using parametric simulations with horizontal conductors in uniform soil. The versatile proposed model is further applied to a realistic case accounting for transformer neutral return current, revealing significant discrepancies in touch voltages compared to simplified approaches.