The application of cepstrum technique in power cable fault detection

A technique for detecting power cable fault is described. The cable faults are usually characterized by degradation of the dielectric, either by water inclusion or physical cracking and associated voids. Voltage reflected at the fault is modeled as distorted echo. In this technique, a voltage step test signal propagates down the line and reflects energy when a change in impedance occurs. Digitized samples are taken along the return waveform. The power cepstrum of the data is then computed; a simple echo of delay τ produces a ripple in the cepstrum domain of quefrency τ yielding information about the fault location.