Phase Difference Method for Two-end Partial Discharge Locating System of Power Cables

A method to locate partial discharges in power cables is presented in this article. The method is based on the phase difference between the first arriving waves of a partial discharge pulse at the cable terminals. The phase difference as a function of frequency is obtained using the cross-Fourier spectral density function. The partial discharge location can be determined from the slope of the unwrapped phase difference. The performance of the method is tested using the electromagnetic transient program on a 20 kV, 2-km underground cable, which takes into account the frequency-dependent parameters. The statistical results indicate high location accuracy.