A two-terminal fault location approach based on unsynchronized phasors

This paper presents the fundamentals of a two-terminal impedance-based fault location algorithm for transmission lines which works with unsynchronized phasors. The proposed approach is iterative and takes into account a distributed line model. At each iteration, the voltage magnitudes calculated from the data of the sending and remote ends are approximated by two straight lines, and the fault location estimate is then defined as the intersection point of these two lines. The process ends when the difference between two successive fault location estimates becomes smaller than a tolerance stipulated by the user. Since the search process is based on voltage magnitudes, synchronism is not required between the measurements obtained at each transmission line terminal.