Fault Detection During Power Swings Using the Properties of Fundamental Frequency Phasors

Among short-circuit faults, those occurring during power swings are more harmful to power system stability and thus, they should be detected quickly and reliably. However, discrimination of power swing and such kinds of faults is not always easy, especially in case of three-phase faults which are symmetrical similar to power swings. This paper shows that fundamental frequency phasors of voltage and current have some proper characteristics which can be used for the mentioned discrimination. In doing so, two new fault detection methods are proposed and tested on simulated systems considering singlemode and multi-mode swings. Field data are also utilized to substantiate the presented analyses. The obtained results demonstrate the correctness of presented analyses and the efficiency of proposed methods in fault detection during power swings.