Power system stability enhancement using unified power flow controllers

The use of the supplementary controllers of a unified power flow controller (UPFC) to damp low frequency oscillations is investigated. The potential of the UPFC supplementary controllers to enhance the dynamic stability is evaluated by measuring the electromechanical controllability through singular value decomposition (SVD) analysis. Individual designs of the UPFC controllers using particle swarm optimization (PSO) technique are discussed. A nonlinear, time-domain objective function is considered. The effectiveness of the proposed controllers on damping low frequency oscillations is tested through eigenvalue analysis and non-linear time simulation. For comparison, power system stabilizer (PSS) performance is also included.