The Feasibility of Cable Sheath Fault Detection by Monitoring Sheath-to-Ground Currents at the Ends of Cross-Bonding Sections

This paper aims at checking the possibility that cable sheath faults in unipolar three-phase HV and extra HV cables with sheath cross-bonding systems can be detected by monitoring sheath-to-ground currents at the solid bonding ends of major cross-bonding sections. This goal is achieved by calculating such currents for some reference case studies of faults of the outer thermoplastic jacket in unipolar three-phase land cables for power transmission in flat formation. The case studies differ as to cable voltage ratings, resistance and location of the fault, symmetry of minor sections, and number of major sections. The results show that the aforementioned possibility does exist, particularly for some fault types and for sufficiently high cable load.