A digital fault-location algorithm taking into account the imaginary part of the grounding impedance at the fault place

The paper presents a new digital fault location algorithm developed for the determination of the location of the transmission line faults. The calculations for the estimation of the fault location are performed using one-terminal voltage and current data of the transmission line. The development of the algorithm is based on the detailed consideration of all the return paths (ground wire, towers, and substation grounding electrodes) of the ground fault current to its sources (the power system). The algorithm takes into account all of the factors important for the accuracy of the estimation (i.e., fault impedance, fault current component supplied from the opposite end of the line, and the prefault current). Also, the imaginary part of the fault impedance is not ignored as is the case with the previously published methods. The proposed algorithm was tested using simulated current data. Sample test results are also included.