The Impact of the Grounding System on the Lightning Performance of Transmission Lines: a Sensitivity Analysis

The paper presents some numerical studies aiming at investigating the effect of different grounding system structures on the lightning performance of transmission lines equipped with surge arresters. The model takes into account the frequency dependence of the grounding system. The transmission line is treated in frequency domain by use of the BLT (Baum-Liu- Tesche) equations while the grounding system, is simulated using general electromagnetic model solved by means of the Method of Moment (MoM) in frequency domain. The lightning-originated overvoltages in presence of the surge arrester are then calculated in frequency domain using the Arithmetic Operator Method (AOM). A sensitivity analysis has been done studying the effect of different parameters including soil electromagnetic properties, grounding system structure and injection point on the lightning- originated overvoltages.