Impact of Soil-Resistivity Uncertainty on EMTR-Based Fault Location in Overhead Transmission Lines

Electromagnetic Time Reversal (EMTR) has emerged as a highly accurate technique for locating faults in overhead transmission lines. However, its performance depends on the line modeling and soil parameters used in the backpropagation stage, particularly soil resistivity, which is often poorly known in practice. This paper evaluates the influence of soil-resistivity mismatch on EMTR-based fault location through controlled numerical experiments using frequency-domain line modeling. Three scenarios are investigated: the impact of loss modeling, discrete deviations between true and assumed soil resistivity, and a continuous sensitivity analysis. Results show that EMTR remains remarkably robust. Even when the assumed soil resistivity differs from the true value by up to two orders of magnitude, the resulting localization error remains below 1 km for a 10-km line (typically below 5% of the line length). These results demonstrate that EMTR can maintain reliable fault-location accuracy even when soil parameters are only approximately known.