Optimization of Overcurrent Protection Coordination in Medium-Voltage Mining Electrical Systems Considering Ground Faults and Dynamic Operating Conditions

Ramos S.M.H.; Reyes L.M.P.; Camayo J.M.F. · 2026 8th International Conference on Information Science, Electrical and Automation Engineering, ISEAE 2026 (2026) · DOI: 10.1109/iseae69422.2026.11544499

Resumen

Modern mining electrical systems operating at medium voltage levels are characterized by dynamic load conditions, frequent topological changes, and the presence of high-resistance ground faults, which significantly complicate the coordination of overcurrent protection systems. Conventional coordination methods, typically based on static operating conditions, fail to ensure selectivity and sensitivity under such scenarios. This paper proposes an advanced coordination methodology for overcurrent relays (ANSI 50/51 and 50N/51N) in a 34.5/7.2 kV mining distribution system, integrating load flow analysis, short-circuit studies, and a constraint-based optimization approach. The proposed method incorporates multiple operating scenarios (maximum, medium, and minimum demand) and considers high-resistance ground faults to enhance protection performance under realistic conditions. A detailed case study implemented in DIgSILENT PowerFactory demonstrates that the proposed methodology improves coordination time intervals (CTI), increases sensitivity to low-magnitude ground faults, and reduces the risk of non-selective tripping. Specifically, the coordination margin was improved by up to 35%, while maintaining system stability and operational reliability. The results highlight the effectiveness of incorporating dynamic operating conditions into protection coordination strategies for mining power systems, contributing to more robust and reliable protection schemes.

Instituciones: Universidad Continental