Estimation Methods of Short Circuit Current using Normal PMU Measurements and Field Testing

Abstract

This paper proposes estimation methods of short circuit current using phasor measurement unit (PMU) measurements (phasors). The methods follow the basic notion of representing the source side of a power system by an equivalent circuit with a voltage behind back impedance, and employ a set of voltage and current phasors measured at substations during the normal variation of loads in their estimation. In order to improve the estimation accuracy of the proposed methods, the concept of using the changes between the consecutive phasors is introduced. Furthermore, to make the methods applicable to the real world system, a reference phasor concept to remove the effects of system wide frequency variations and a filtering process to filter out the outlier phasors, are proposed and implemented. The validity and effectiveness of the proposed methods were checked and confirmed using experiments and field tests.