A Selective Method for Identifying Single-Phase Ground Faults with Transient Resistance in Isolated Neutral Medium-Voltage Networks
Jetpissov M. Tergemes K. Sheryazov S. Zhauyt A. Sadykbek T. Berdibekov A. Smailova G.
November 2025Multidisciplinary Digital Publishing Institute (MDPI)
Energies
2025#18Issue 21
Single-phase ground faults (SPGFs) in isolated neutral medium-voltage networks are difficult to detect, especially under high transient resistance. This paper proposes a centralized ground fault protection unit (CGFPU) that combines zero-sequence current (ZSC) magnitude and phase-angle analysis to enhance selectivity. Simulation results show that as transient resistance increases from 1 Ohm to 10 kOhm, fault currents decrease significantly, yet the CGFPU reliably identifies the faulty feeder by exploiting the characteristic 180° phase shift of ZSC phasors. The method remains selective with angular deviations up to ±20° and distinguishes between feeder and busbar faults. Compared with conventional amplitude- or model-based techniques, the proposed approach achieves faster detection, lower computational complexity, and robustness against unbalanced and charging currents. Furthermore, the CGFPU operates adaptively in alarm or trip mode depending on fault severity, thus preserving continuity for high-resistance faults and ensuring rapid isolation of bolted faults. These contributions establish a practical, scalable, and future-ready solution for SPGF protection in medium-voltage isolated neutral networks.
capacitive current , isolated neutral network , relay protection , single-phase ground fault , transient resistance , zero-sequence current
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Department of Electricity Supply and Renewable Energy Sources, Almaty University of Power Engineering and Telecommunications Named After G. Daukeyev, Almaty, 050013, Kazakhstan
Department of Electric Power Engineering, L.N. Gumilev Eurasian National Research University, Astana, 010000, Kazakhstan
Department of Electronic Engineering, Almaty University of Power Engineering and Telecommunications Named After G. Daukeyev, Almaty, 050013, Kazakhstan
Department of Energy, Mukhamedzhan Tynyshpaev ALT University, Almaty, 050012, Kazakhstan
Department of Energy, Satbayev University, Almaty, 050013, Kazakhstan
Department of Electricity Supply and Renewable Energy Sources
Department of Electric Power Engineering
Department of Electronic Engineering
Department of Energy
Department of Energy
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