Zero-Sequence Voltage Suppression and Fault Arc Extinction Considering Three-Phase Parameter Asymmetry for Hybrid Grounding System

To address the challenge of low fault identification in low-resistance grounding system during single-phase high-resistance ground faults, a hybrid grounding system combining flexible device with low resistance is applied. In scenarios of three-phase parameter asymmetry, the zero-sequence voltage generated under normal operational conditions adversely affects fault detection in low-resistance grounding method. Moreover, traditional methods of current injection for arc extinguishing leave residual voltage, leading to incomplete fault clearance. Therefore, strategies for suppressing zero-sequence voltage due to three-phase parameter asymmetry and for extinguishing single-phase ground faults are introduced based on the hybrid grounding system. By injecting the appropriate current through an inverter, this approach not only ensures the rapidity of low-resistance grounding fault detection under normal conditions but also achieves complete arc extinction in the event of high-resistance grounding faults, thereby enhancing the power supply reliability of the distribution network. The simulation and HIL-based results validated the effectiveness of the proposed method.