This paper proposes an improved sine-cosine algorithm (ISCA) based 2-DOF-PID controller for load frequency control. A three-area test system is built for study

while some physical constraints (nonlinearities) are considered for the investigation of a realistic power system. The proposed method is used as the parameter optimizer of the LFC controller in different scenarios. The 2-DOF-PID controllers are used because of their capability of fast disturbance rejection without significant increase of overshoot in set-point tracking. The 2-DOF-PID controllers' efficacy is observed by examining the responses with the outcomes obtained with PID and FOPID controllers. The simulation results with the suggested scheme are correlated with some of the existing algorithms

such as SCA

SSA

ALO

and PSO in three different scenarios

i.e.

a disturbance in two areas

in three areas

and in the presence of physical constraints. In addition

the study is extended to a four-area power system. Statistical analysis is performed using the Wilcoxon Sign Rank Test (WSRT) on 20 independent runs. This confirms the supremacy of the proposed method.