Damping Inter Area Oscillations of Power Systems by a Fractional Order PID Controller

A Fractional Order PID (FOPID) controller to damp inter area oscillations of power systems is studied. FOPID is a PID whose derivative and integral orders are fractional rather than integer. The difficulty of design a FOPID controller is how to determine the five key parameters of FOPID. This paper uses Genetic Algorithm Particle Swarm Optimization (GAPSO) algorithm to design the FOPID controller. A new cost function is defined to facilitate the control strategies over the time domain specifications. Comparisons with a conventional PID controller are made and it is shown that the proposed FOPID controller can highly improve the system robustness with respect to model uncertainties.