Natural Frequency-Based Line Fault Location in HVDC Lines

To predict the location of dc line-faults in an HVDC system, a novel algorithm based on traveling-wave natural frequency using 10-ms current data from the single end is proposed in this paper. The relationship among the natural frequency of traveling wave, fault distance, and reflect coefficient at the terminal of the transmission line is presented. The multiple signal classification method is employed to extract the dominant natural frequency through the spectrum analysis of the traveling wave. The traveling-wave velocity and reflect coefficient under the dominant natural frequency are calculated to identify the fault location. Performance of the proposed fault-location algorithm is studied through detailed simulations carried out by using the electromagnetic transient simulation software PSCAD/EMTDC. The method does not need to identify the surge arrival time and it is more robust compared to the traditional traveling-wave-based fault-location methods. The simulation results have shown that the proposed method is valid and can locate the faults occurring on HVDC transmission lines accurately.