An optimized criterion for line selection based on zero-sequence admittances for high-resistance SPG faults in the intelligent grounding distribution system

In the case of a single-phase grounding (SPG) fault in the intelligent grounding distribution system, this paper analyzes the change features of the fault lines’ and the non-fault lines’ zero-sequence admittance amplitudes and phase angles before and after the removal of the busbar grounding arc quenching device. Furthermore, the paper puts forward a new criterion for line selection for SPG faults based on the system’s and the lines’ zero-sequence admittances. Applicable to the intelligent grounding distribution system, this criterion fixes the problems of potential failure protection and poor sensitivity of existing protective methods in the case of high-resistance grounding. In addition, it is superior and exclusive for unifying the action thresholds for all lines in the system. In the simulation experiment, different transition resistances and different locations of the fault point are input to understand their impacts on the criterion and verify its effectiveness and reliability. The simulation results show that this criterion is insusceptible to the fault’s location and that the selection result will become more stable and reliable as the transition resistance rises. This criterion is highly serviceable in practical engineering.