Optimal Tuning of Unified Power Flow Controller Using Firefly Algorithm to Improve Damping of Inter-Area Oscillations in Multi-Machine System

The interconnection system faces inter-area oscillation challenges that affect power system stability. Conventional Power System Stabilizer (PSS) cannot provide effective damping to the inter-area oscillations. This paper deals with a Proportional Integral (PI) controller as a damping control scheme of the Unified Power Flow Controller (UPFC) to improve the damping of inter-area oscillation in a multimachine system. The proposed PI Controller-based UPFC is tuned using the Firefly Algorithm (FA), and the performance is compared with PSS. Simulation results show that the proposed PI Controller-based UPFC provides a better stability margin than PSS under the different conditions and effectively reduces the overshoot by 53%, accelerating the settling time by 74%, and minimizing the area graph by 85%.