Earth Fault Current Analysis for Complex Power Cable Transmission Lines

This presentation explains how to perform accurate earth fault current analysis for substations connected by cable transmission lines. A circuit model approach is proposed, where the transmission line is represented by its dimensional and electrical parameters, and the mutual impedances are considered, to solve for the fault currents and voltages.

Two case studies involving complex cable systems are presented. The first case study examines the EPR for a hybrid cable and overhead transmission line with a UG/OH transition station. The second case study involves a single-point and cross-bonded cable transmission line, where variations to the critical line parameters such as screen resistance, ECC position and conductor size, and earth resistances and their impacts on the EPR are explained.