Research on Early Three-Core Power Cable High-Impedance Fault Location Method Based on the Spectrum of Propagation Functions

High-impedance faults in three-core power cables gradually develop into serious faults. Hence, localizing high-impedance faults is the key to ensuring transmission line reliability. The fault location cannot be accurately located due to the low detection sensitivity of the time-domain reflection (TDR) method and interference peaks in the localization results of the frequency-domain reflection (FDR) method. A new spectrum of propagation function (SPF) based fault localization method is proposed in this paper. Cable's S-parameter model is first described to reveal the reason for the change in the resonant frequency in the SPF due to high-impedance faults. In addition, the integral transform algorithm is employed to extract the cable's fault location from the SPF; the method's feasibility is numerically verified. Finally, high-impedance faults are set up in a three-core cable of 100 m in length, and the SPF of the cable is measured via a vector network analyzer. Compared with the TDR and FDR methods, the proposed approach is more capable of identifying high-impedance faults and more dependable on localization results. The fault localization error is within 0.16%, which has good application value.