Incipient Fault Localization Using Sheath and Impedance-Based Method for Single-Bonded Underground Cables

Electric energy plays a fundamental role in driving global productivity and is essential for industrial, commercial, and residential activities. As energy demand continues to rise, insulated power cables have become increasingly critical in modern power grids, ensuring reliable transmission and distribution. However, insulation aging can progressively lead to faults and result in system outages. Given that over 70% of these interruptions in isolated cables are caused by phase-to-ground faults, this presents a significant challenge to the stability and reliability of power systems. Current fault detection strategies aim to identify incipient faults–small, transient electrical discharges within the insulation–before they escalate into permanent faults. Despite this, traditional methods face limitations in terms of precision and applications, especially for single-bonded cables with short lengths and low impedance values. To overcome these limitations, this paper proposes an enhanced impedance-based method for locating incipient faults using the metallic sheath of single-bonded cables. This method integrates metallic sheath parameters to improve the accuracy of incipient fault localization while avoiding the uncertainty associated with estimating unknown parameters. Unlike previous approaches that rely on voltage and current measurements at both ends of the cable, the proposed method simplifies data collection by reducing the number of monitored parameters. Simulations validate the proposed approach, demonstrating its ability to reduce errors in locating fault points in underground cables. The primary contribution of this study is improving the accuracy of incipient fault localization, offering a more efficient and effective solution for identifying and locating faults in insulated cables at their earliest stages.