摘要：This paper focuses on systematic approach towards damping the tie-line power oscillations inan interconnected thermal power plant using Unified Power Flow Controller (UPFC) withVariable Structure System (VSS) Controller. Conventionally, Automatic Generation Control(AGC) is carried out by primary governor control and secondary Proportional- Integral (PI)controller. PI controller helps to damp out tie-line power and frequency oscillations whensubjected to unit step load disturbance. Ziegler Nichols’ (ZN) method is used in tuning the gainsof conventional PI controller and VSS controller. Optimal switching of VSS controller iscarried out by the performance indices. UPFC based damping controller helps to stabilize thetie-line power oscillations of power system. The simulation indicates reduced frequency and tielinepower transient with much faster settling time is obtained by using UPFC along withsecondary VSS controller.
