Fault location for overhead and cable hybrid transmission line in VSC-HVDC system

Because the traditional fault location method cannot be applied to overhead and cable hybrid transmission line in the VSC-HVDC system, this paper proposes a novel fault location method, which primarily uses the principle of first determining the fault segment and then locating the fault point in the fault segment. Two voltage symbolic functions are defined, and the fault segment is determined according to the different numerical combinations of the two voltage symbolic functions. Through combining adaptive characteristic scale decomposition with improved general local frequency decomposition to adaptively extract the fault characteristic component, the intra-segment location equation is established based on the characteristic component to locate the fault point. The simulation results verify that the proposed method can accurately locate the fault point for the overhead and cable hybrid transmission line in the VSC-HVDC system.