摘要：The objective of this work is the coordinated design of controllers that can enhance damping of power system swings. With presence of flexible AC transmission system （FACTS） device as unified power flow controller （UPFC）, three specific classes of the power system stabilizers （PSSs） have been investigated. The first one is a conventional power system stabilizer （CPSS）; the second one is a dual-input power system stabilizer （dual-input PSS）; and the third one is an accelerating power PSS model （PSS2B）. Dual-input PSS and PSS2B are introduced to maintain the robustness of control performance in a wide range of swing frequency. Uncoordinated PSS and UPFC damping controller may cause unwanted interactions; therefore, the simultaneous coordinated tuning of the controller parameters is needed. The problem of coordi- nated design is formulated as an optimization problem, and particle swarm optimization （PSO） algorithm is employed to search for optimal parameters of controllers. Finally, in a system having a UPFC, comparative analysis of the results obtained from application of the dual-input PSS, PSS2B, and CPSS is presented. The eigenvalue analysis and the time-domain simulation results show that the dual-input PSS ＆ UPFC and the PSS2B ＆ UPFC coordination provide a better performance than the conventional single-input PSS ＆ UPFC coordination. Also, the PSS2B ＆ UPFC coordination has the best performance.