Employment of quasi oppositional SSA-based two-degree-of-freedom fractional order PID controller for AGC of assorted source of generations

A novel quasi-oppositional-based salp swarm algorithm (QSSA) is used to obtain the optimal values of controllers for automatic generation control of the two-area, assorted source of the generation-based power system. Thermal, hydro, and gas generating units are considered in the power system. Optimal values of proportional-integral-derivative (PID) controllers obtained using SSA and QSSA are compared with that of PID controllers based on differential evolution, teaching learning-based optimisation, and imperialist competitive algorithm. Observing the superiority with a QSSA-based PID controller, the study is protracted to obtain the optimal values of two-degree-of-freedom conventional PID (2DOF-PID) and 2DOF fractional order PID (2DOF-FOPID) controller with SSA and QSSA techniques. It is evidenced that QSSA outperforms SSA and also the QSSA-based 2DOF-FOPID controller establishes a better dynamic response than other controllers. 2DOF-FOPID controller is also employed for the system with generation rate constraint (GRC). The complete analysis is carried out by applying a step load disturbance of 1 p.u. in area-1. Robustness of the controller is verified by varying the systems' parameters and a randomly varying loading pattern in both areas with and without GRC. In both cases, the proposed QSSA-based 2DOF-FOPID controller is found firmly robust.