High Resistance Grounding Detection Method of Flexible Grounding System Based on Fault Component Phase Reactive Power Ratio

Aiming at the problem that the traditional zero-sequence current protection cannot operate reliably when a single-phase high-resistance grounding fault occurs in a flexible grounding system, this paper proposes a high-resistance grounding protection method for flexible grounding system based on the ratio of fault component phase reactive power. Firstly, the characteristics of three-phase reactive power of fault line and non-fault line fault components after low resistance parallel connection and before fault are analyzed. Then, based on the characteristic difference between the two, the fault criterion is constructed by using the maximum value of reactive power ratio between each phase. Finally, the proposed protection method is simulated and verified by building a 10 kV flexible grounding system distribution network model in PSCAD. The results show that when a single-phase grounding fault occurs in the flexible grounding system, the protection method can effectively distinguish the fault line from the non-fault line and has good fault resistance tolerance.