UPFC supplementary stabilizer controller design using optimization methods

This paper presents the application of Unified Power Flow Controller (UPFC) to enhance damping of Low Frequency Oscillations (LFO) at a Single-Machine Infinite-Bus (SMIB) power system installed with UPFC. Since UPFC is considered to mitigate LFO, therefore a supplementary damping controller based UPFC like power system stabilizer is designed to reach the defined purpose.  Optimization methods such as Particle Swarm Optimization (PSO) and Genetic Algorithms (GA) are considered to design UPFC supplementary stabilizer controller. To show effectiveness and also comparing these two methods, the proposed methods are simulated under different operating conditions. Several linear time-domain simulation tests visibly show the validity of proposed methods in damping of power system oscillations. Also simulation results emphasis on the better performance of PSO in comparison with GA method.   Key words: Flexible AC transmission systems, unified power flow controller, low frequency oscillations, particle swarm optimization, genetic algorithms.