Fault Location Method for Three-Core Cable Using Amplitude Ratio of Shield-Grounding Wire Currents

Abstract

With significant technological advancements in power grids, three-core cables are widely employed for their safety and other benefits. In general, three-core cables in medium-voltage distribution systems are laid underground during operation. As a result, the harsh working environment and complex fault conditions can bring massive challenges to fault location issues. To address the problem, the distinctive cable features are extensively considered in this article, including relatively larger capacitance, cable shield effects, and shield bonding methods. Initially, an equivalent cable model is developed to analyze the relationship between shield-grounding wire currents and the fault point. A single-phase grounding fault location method is then formulated based on the ratio of shield-grounding wire currents at both terminals. In PSCAD/EMTDC, a range of fault scenarios are simulated to verify the proposed method. In comparison to conventional similar approaches, the proposed method exhibits higher accuracy and robustness to fault resistance and diverse fault conditions. Finally, the effectiveness of the proposed method is validated on a real 10 kV distribution network experimental platform under several fault scenarios.