A fault location method based on traveling wave natural frequency used on ±800kV UHVDC transmission lines

A new single ended fault location method is proposed using traveling wave frequency information for ultra high voltage direct current transmission lines. Being different from the traditional telegrapher´s equations based analyzing methods, the proposed method is based on the traveling wave natural frequency. The transient signals are analyzed to extract the natural frequencies using discrete Fourier transformation (DFT) after the fault occurred at the line. Then the fault distance can be calculated with the relationship among the fault distance, the dominant natural frequency and the terminal conditions of transmission line. A simulation model of 800 kV UHVDC transmission is built in PSCAD/EMTDC. Various transmission line fault situations are considered to locate the fault point with different transition resistance. The results confirm that the proposed method is feasible and accurate.