Traveling Wave-Based Fault Location on Two-Segment Hybrid Lines

In this paper, a traveling wave (TW)-based fault location algorithm for two-segment hybrid transmission lines (HTLs) is evaluated. Its formulation is able to accurately estimate the fault location on HTLs taking into account the different propagation velocities on each segment. The Alternative Transients Program (ATP) was used to simulate a wide variety of fault scenarios in a 220 kV/50 Hz two-segment HTL consisting of an overhead transmission line (OHTL) in series with an underground high voltage cable line (HVCL). Different fault distances, HVCL lengths, uncertainties in HVCL line parameters and two-terminal data time synchronization errors were taken into account in ATP simulations. For each simulated case, the performances of the HTL-dedicated fault location algorithm and classical two-terminal TW-based fault location method are compared. The obtained results show that adapted versions of the classical two-terminal fault location method do not yield accurate fault distance estimations, thereby HTL-dedicated solutions must be used. However, time synchronization errors and uncertainties in electrical line parameters are still sources of errors for both approaches.