Intelligent coordinated control of unified power flow controller and power system stabilizer to damp inter-area oscillations in multi-machine power systems

The aim of this thesis is to study the coordinated design of the unified power flow controller (UPFC) and two power system stabilizers (PSS) in a multi-machine power system using particle swarm optimization technique. To accomplish this task, the coordinated controller design problem has been formulated as an optimization problem that consists of an objective function and constraint equations. The effectiveness of the proposed design has been tested through time-domain simulations under different operating conditions in a multi-machine power system. It has been shown that without coordination, even if both PSSs and UPFC operates satisfactorily in a separate manner, an adverse effect or a negative interaction between controllers negatively affects power system transient stability. However, with coordinated design, the inter-area oscillations have been effectively damped. Key words: Power system stabilizer, PSS, unified power flow controller, UPFC, inter-area oscillation, transient stability, particle swarm optimization