Distributed self-healing control of single-phase grounding fault in neutral point non-effective grounding system

In distribution networks, single-phase grounding occurrences in non-effectively grounded systems do not result in short-circuits, thus leading to low fault currents. Particularly in high-resistance grounding scenarios, fault currents become extremely low, increasing the risk of protection misjudgments. To enhance the speed and accuracy of self-healing during such faults, a distributed self-healing control method based on flexible grounding and zero-sequence current analysis for non-effectively grounded systems is proposed. This method employs peer-to-peer distributed self-healing and flexible grounding techniques to convert isolated or arc-suppressed neutral systems to low-resistance grounded systems. Additionally, a localization criterion unaffected by neutral grounding modes is introduced, utilizing deviations in zero-sequence current upstream and downstream of the fault as distinguishing characteristics. The proposed method is straightforward in principle and leverages existing terminal equipment for accurate and swift fault processing. Simulation results validate the method's resilience to transition resistance and neutral grounding conditions, demonstrating its suitability for single-phase grounding fault localization across all system types. The research findings effectively ensure the accuracy and swiftness of self-healing during single-phase grounding faults in non-effectively grounded systems.