An Iterative Two-Terminal Fault-Location Method Based on Unsynchronized Phasors

This paper presents a two-terminal fault-location method which works with unsynchronized phasors. The algorithm is iterative and takes a distributed line model into account. At each iteration, the voltage magnitudes computed from the voltage and current phasors measured at the sending and receiving ends are approximated by two straight lines, and the fault-location estimate is obtained by the intersection point of these two lines. The process ends when the difference between two successive fault-location estimates reaches a threshold stipulated by the user. Since the search process is based on voltage magnitudes, the proposed approach does not require synchronism between the measurements obtained at each transmission-line terminal. The evaluation tests show that the fault-location error of the proposed approach is negligible if the phasors measured at both line ends and the line parameters are accurate. For actual fault conditions, the fault-location error is dependent on the accuracy of the phasor magnitudes and transmission-line parameters.