A Novel Single-Phase Earth Fault Feeder Detection by Traveling Wave and Wavelets

This paper discusses the characteristic of traveling waves produced by a single-phase earth fault in an ineffectively grounded distribution grid: the traveling wave current of the fault feeder is in the opposite direction to the others. A complex frequency B-Spline (CFBSP) wavelet is presented to analyze the singular signals of the zero modes of the fault traveling waves in the initial process of the failure: the wavelets coefficient maximum polarity and phase angle of the zero mode of the fault feeder traveling wave current are right the inverse of the others. So a novel earth failure detection technique is introduced to distinguish the fault feeder by comparing the wavelets coefficients maximum polarity and phase-angle of the zero modes of the traveling waves´ currents in some scales. The influences of the fault spot intermittent arc, transformer and its neutral point are proved to be feeble. So the detection technique is very exact, available and universal, it is proved by a great deal of simulating test.