Development of a Fault Localization Algorithm Based on SFWR Considering Propagation Velocity Changes with Propagation Distance

Reflectometry, which is a kind of electrical diagnostic method, is widely used to localize faults in power cables. However, the signals used in the reflectometry undergo attenuation and dispersion along the propagation distance, causing changes in the frequency components of the signals. It leads to changes in the propagation velocity and reduces the impedance mismatch detection performance such as fault and end point. If the changes in propagation velocity according to the propagation distance are not considered, the errors accumulate as the propagation distance increases. To solve this problem, we develop the long-length HTS cable model based on actual measurement data and use the stepped-frequency waveform reflectometry (SFWR) to derive the propagation velocity that changes depending on the propagation distance. In this paper, the proposed algorithm improves the impedance mismatch detection performance of the conventional SFWR based on the estimated propagation velocity.