Research on High-impedance Grounding Fault Prevention and Control Technology of Distribution network Based on Single-phase Isolation Transformer and Edge Phase Additional Capacitance

High-impedance grounding faults represent a prevalent yet challenging issue to identify within distribution networks. Due to its small fault currents and long duration, it often cause secondary disasters such as wildfires. Current prevention and control technologies for high-impedance grounding faults have limitations in addressing issues such as arc ignition, fault current limitation, and wildfire prevention. In response to these challenges, this paper introduces a novel asymmetric operating configuration utilizing a single-phase isolation transformer complemented by the Additional capacitor. Through theoretical analysis and simulation studies, this paper reveals the inherent relationships between fault current, phase voltage, zero-sequence voltage, and high-impedance grounding fault characteristics. A control method has been designed to optimize the three-phase voltage distribution in the distribution network. The simulation results show that the proposed structure can significantly reduce the edge phase voltage, decrease the magnitude of fault current, effectively suppress the conditions for arc generation, prolong the ignition delay time, and thereby reduce the risk of wildfire. This paper provides a new approach for the prevention and control of high-impedance grounding faults and holds significant value for engineering practice as well as theoretical guidance.