Equilibrium optimizer‐tuned cascade fractional‐order 3DOF‐PID controller in load frequency control of power system having renewable energy resource integrated

Summary This paper suggests a novel cascade fractional‐order controller (CC‐FOC) comprising of three degrees of freedom proportional‐integral‐derivative (3DOF‐PID) and tilt‐integral‐derivative (TID) controllers for solving the load frequency control problem of an interconnected power system integrated with DFIG‐driven wind power system. In the proposed CC‐FOC, 3DOF‐PID and TID controllers are used as slave and master controllers, respectively, to alleviate system oscillations and to improve system stability in the wake of sudden perturbations. A novel meta‐heuristic technique, namely equilibrium optimizer (EO), has been adopted and successfully implemented for concurrent tuning of the proposed controller's different parameters. Simulation outcomes of the EO have been evaluated with those attained by gravitational search algorithm, grey wolf optimization, and the results are reported in the literature. The efficacy of the proposed CC‐FOC is established by contrasting its responses with the outcomes of 3DOF‐PID, 2DOF‐PID, TID, and conventional controllers. The mastery of the proposed controller is further assessed, including system nonlinearities like GRC and GDB. The results obtained through extensive simulation reveals that the suggested approach significantly enhances system performance compared to the prevalent controllers of the existing literature. Finally, the robustness of the test system having CC‐FOC integrated is demonstrated against wide variation in system parameters by employing Kharitonov's theorem. Figure 1. Model of non‐reheat thermal power plant having DFIG driven WPS integrated. Figure 2. Block diagram of 3DOF‐PID controller.