Nonlinearity Characteristic of High Impedance Fault at Resonant Distribution Networks: Theoretical Basis to Identify the Faulty Feeder

Feeder identification is indispensable for distribution networks to locate faults at a specific feeder, especially when measuring devices are insufficient more precisely. For the high impedance fault (HIF), feeder much challengeable and related approaches still in early stage. This paper thoroughly reveals nonlinearity characteristics of different feeders HIF happens three-wire system that with resonant grounded neutral (RGN). Firstly, diversity existing HIFs explained from perspective energy. Then, zero-sequence current differs between healthy faulty deduced theoretically. Effects detuning index Petersen coil, damping ratio system, length all considered. Afterward, these theoretical conclusions verified by cases experimented real 10kV system. Finally, after indicating problems classic phase-relationship-based algorithm, we suggest an improved method based on phase differences harmonic currents feeders. The effectiveness has been verified.