Improved-salp swarm optimized type-II fuzzy controller in load frequency control of multi area islanded AC microgrid

Abstract The present article deals with load frequency control (LFC) in an islanded two area AC microgrid (MC) system. In this study the proposed two area MG system comprises different micro sources including Micro-turbine (MT), Diesel engine generator (DEG) and Fuel Cells (FC) which are primarily responsible for balancing load and power generation in an interconnected system. MG in grid-connected mode has lower possibility of frequency control problem due to active presence of utility grid. Whereas MG in islanded mode faces huge frequency control problem due to dynamic nature of different renewable energy sources (RES) and different uncertainties like wind power fluctuations, disturbances in solar irradiation power, dynamics in applied load and system parameters (damping coefficient & Inertia constant). In regard to this the present article proposes a robust type-II fuzzy PID controller to create secondary frequency control loop for maintaining both frequency and tie-line power to their nominal values under different uncertainties. For performance study, the proposed type-II fuzzy PID controller performances are compared with type-I fuzzy controller, PID and PI controllers. To obtain optimal gain values of above controllers, a meta-heuristic improved-salp swarm optimization (I-SSO) algorithm has been implemented and proposed I-SSO technique performances are compared with original SSO, Particle swarm optimization (PSO) and Genetic Algorithm (GA) techniques. Finally it is observed from different performance analysis that proposed I-SSO tuned type-II fuzzy controller exhibits superior performances for load frequency control in multi-area islanded AC microgrid system under different uncertainty conditions.