Water cycle algorithm-based load frequency controller for interconnected power systems comprising non-linearity.

This study addresses proportional-integral-derivative (PID) optimal fine tuning of load frequency controllers for multiarea interconnected power systems. For realistic study, generation rate constraints are considered to increase system nonlinearity. The proposed method is applied to equal and unequal multi-area interconnected power systems. A methodology based on water cycle algorithm (WCA) is proposed. WCA is applied to generate optimal fine settings for the four parameters of the PID. A constrained optimisation problem with relevant integral of time multiplied by summation of absolute errors as an objective function is established. The time-domain dynamic performances using the generated optimal PID parameters are demonstrated under disturbed load conditions. At this moment, to show the robustness of the cropped optimised PID parameters, sensitivity analysis under uncertainty conditions is made by varying the system parameters from their nominal values. Specifications of time-domain dynamic performances are compared with other competing and Ziegler-Nichols PID tuning techniques which attest the significance of the proposed WCA-based LFC. Finally, the proposed WCA-based PID controllers are verified against random step load perturbations with different sampling times. [ABSTRACT FROM AUTHOR]