Propagation Time Estimation of Transmission Lines using Time Domain Reflectometry

This paper proposes a novel time domain reflectometry method to estimate the propagation time of transmission lines in medium-voltage (MV) networks. In the proposed method, a single travelling wave detector (TWD) unit is installed at the zone substation where a switching action is performed. The subsequent recorded transients are then matched to the arrival times and amplitudes of expected transients corresponding to characteristic paths in the network. A combinatorial approach is proposed to mitigate interference from multiple-paths reflected transients. The matching method generates a list of possible propagation times from which the one that best fits the measurements is selected. The performance of the proposed method is evaluated on multiple branched networks. The results exhibit accurate estimation of propagation times for test networks.