Fault Line Selection Based on Zero Sequence Power Direction of Transient Fundamental Frequency in MV Network Grounded with Arc Extinguishing Coil

For many years, the fault line selection in an over-compensating network grounded with arc extinguishing coil is not satisfactory. In order to solve the problem, based on zero sequence power direction of transient fundamental frequency, a method of the fault line selection in MV network grounded with arc extinguishing coil is presented in this paper. Through many experiments in the physical experiment model, the presented method is validated by the analysis results. Under any compensating status, instantaneous initial phase of zero-sequence current is always behind that of zero-sequence voltage within 5 ms after grounding fault, and such sharp contrast between instantaneous initial phases at the grounding moment is basic characteristic of differentiating faulted line from non-faulted line, which can be addressed as the zero sequence power direction of transient fundamental frequency.