The objective of this work is to coordinated design controllers that will enhance damping of power system oscillations. With presence of FACTS device as UPFC Two specific classes of PSS have been investigated, the first one is a conventional power system stabilizer (CPSS) and the second is Multiinput power system stabilizer (MPSS). Since uncoordinated CPSS (or MPSS) and UPFC damping controller may cause unwanted interactions, it is necessary to simultaneous coordinated tune the controller parameters. The problem of coordinated design is formulated as an optimization problem and particle swarm optimization algorithm is employed to search for optimal parameters of controllers. A Multi-input signal PSS is introduced to maintain the robustness of control performance in a wide range of oscillation frequency. Finally in a system having a UPFC a comparative analysis between results from application of the MPSS and CPSS is presented. The eigenvalue analysis and the time domain simulation results show that the multi-input PSS and UPFC coordination provides a better performance than the conventional single input PSS and UPFC coordination.
Power oscillation damping, Simultaneous coordinated designing,Unified power flow controller (UPFC), Multi-input power system stabilizer (MPSS)