Fault location algorithm for use with current differential protective relays of double-circuit line

A new algorithm designated for locating faults on a double-circuit line is presented. It is assumed that the fault location function is incorporated into the current differential relay at the particular line end. Besides three-phase currents measured synchronously at both line ends, which are utilized by the protective relays, the fault locator is supplied with three-phase voltage from the local line terminal, and possibly with the zero-sequence current from the healthy parallel line. Formulation of the fault location algorithm is presented and the selected results of the performed ATP-EMTP based evaluation are delivered and discussed.