Analytical Modelling of Power Swing and Validation Using Real Time Digital Simulator

Abstract

Grid disturbance is one of the largest areas of concern in the protection of power systems after high penetration of distributive generation. They are responsible for causing mass blackouts. This paper analytically derives the equations for resistances and reactances as a function of time. The derived expressions were validated using real time digital simulator (RTDS) for variation in power factor of system and frequency of the power swing. Results signify that the derived equations were able to provide the locus of instantaneous values of the real time power swing occurring in the system for changes in power factor and swinging frequency. Two dimensional R-X plane and three dimensional R-X-t space plots were also used to study the static and dynamic variations of impedances in time domain. The expressions r(t) and x(t) will be useful in determining the instantaneous short circuit ratios and also for tuning the impedance relays.