Phase-frequency characteristic of zero sequence networks in neutral indirectly grounded power system

In order to study phase-frequency characteristic of zero sequence current after single-phase earth fault in neutral indirectly grounded power system, this paper starts with the line model of distribution network, and analyzes phase-frequency character of zero sequence impedance for distributed parameter line model. By simulation analyzing, for a single feeder, the factors such as transmission line parameters, length, structure and branch can affect on the characteristic from different aspects. Further more, simulation in PSCAD analyzes phase-frequency character of zero sequence networks after earth fault, and the influence of neutral grounding mode on the character. The study of this paper provides a research basis for the fault line selection methods using transient zero sequence signals.