Traveling-Wave-Based Line Fault Location in Star-Connected Multiterminal HVDC Systems

This paper presents a novel algorithm to determine the location of dc line faults in an HVDC system with multiple terminals connected to a common point, using only the measurements taken at the converter stations. The algorithm relies on the traveling-wave principle, and requires the fault-generated surge arrival times at the converter terminals. With accurate surge arrival times obtained from time-synchronized measurements, the proposed algorithm can accurately predict the faulty segment as well as the exact fault location. Continuous wavelet transform coefficients of the input signal are used to determine the precise time of arrival of traveling waves at the dc line terminals. Performance of the proposed fault-location scheme is analyzed through detailed simulations carried out using the electromagnetic transient simulation software PSCAD. The algorithm does not use reflected waves for its calculations and therefore it is more robust compared to fault location algorithms previously proposed for teed transmission lines. Furthermore, the algorithm can be generalized to handle any number of line segments connected to the star point.