ACCURATE CALCULATION OF FAULT CURRENT PHASORS FOR USE IN FAULT LOCATION

Abstract

In fault location techniques, it is customary to sample voltage and/or current and use these samples to determine the fault location. A lot of work has been reported that uses the synchronized voltage and current samples from one or both terminals of a transmission line and use the resulting phasors for fault location. The inherent error in this approach is the error introduced by the current transformer (CT). This paper illustrates a new method of calculating fault current phasors from the pre- and post-fault voltage phasors using the source impedance at a line terminal. Two transmission lines are simulated with Electromagnetic Transient Program (EMTP) and results are reported to support this method. A method to accurately determine the source impedance is also described. The EMTP results are very promising. This method could result in increasing the accuracy of the existing fault location methods considerably.