Unsynchronized two-terminal fault location estimation

A technique for power system fault location estimation which uses data from both ends of a transmission line and which does not require the data to be synchronized is described. The technique fully utilizes the advantages of digital technology and numerical relaying which are available today and can easily be applied for offline analysis. This technique allows for accurate estimation of the fault location irrespective of the fault type, fault resistance, load currents, and source impedances. Use of two-terminal data allows the algorithm to eliminate previous assumptions in fault location estimation, thus increasing the accuracy of the estimate. The described scheme does not require real-time communications, only offline post-fault analysis. The paper also presents fault analysis techniques utilizing the additional communicated information.