Optimal Design of Fractional Order 2DOF-PID Controller for Frequency Control in Interconnected System

Due to increasing load demand in interconnected system, load frequency control (LFC) is implemented to maintain power quality in terms of frequency regulation. In this work, fractional order two degree of freedom PID (2DOF-FOPID) controller is implemented in a unified power system to regulate frequency abnormality due to abrupt load variation. The examined system includes a geothermal power plant (GTPP), conventional steam power plant (SPP), and dish-sterling solar thermal system (DSTS) in each control area. Considering ITAE as fitness function, grasshopper optimization algorithm (GOA) is utilized to find the finest gains of 2DOF-FOPID controllers during abrupt load perturbation (0.05 p.u.) in control area 2. With consideration of system response evaluative factors (undershoots, settling time, and overshoots), the supremacy of the 2DOF-FOPID controller is established over 2DOF-PID controller and PID controller. By amplifying the load conditions of the control area 2, the robustness of the 2DOF-FOPID controllers is verified.