Active Power Control during Contingency using UPFC

Abstract

The ability of FACTs devices to control phase angle, bus voltages and line impedance in transmission line is what make it capable of controlling power flow. In this paper, we have studied one of most effective FACTS device known as UPFC. Analysis under the contingency is done using 10 bus system
and contingency condition is being introduced in three-phase, delta-delta connected transformer i.e. one base is damaged or accidently opened. Now, it got changed to open delta connection. The open delta transformer still continues to operate as a three-phase bank with decreased rating. The rating of
three phase bank then becomes 57.7% of that of actual bank. But power which was flowing earlier through the original transformer bank is much above the new rating of the transformer, which could damage three phase transformer and eventually make system unstable. So, to solve this problem we introduced Unified power flow controller (UPFC) in the system. UPFC controls the power at all buses in power system and keeps power under normal level. After simulating the system with and without UPFC, it clearly showed the effect in form of power reduction below new rating. UPFC regulated the power not only in the area where it was connected but in the whole power system.