  This paper proposes a novel load frequency control (LFC) approach formulated
on an optimal structure of the coefficient diagram method (CDM) in a two-area
thermal power system. As part of a realistic analysis, nonlinearities related
to governor dead band (GDB) and generation rate constraint (GRC) have been
considered. In this article, a hybrid CDM method is combined with the
optimization of its mathematical equations to achieve an innovative controller.
Furthermore, a new metaheuristic optimization technique called the water cycle
algorithm (WCA) is used to determine the optimal coefficients of the CDM
controller. For the purpose of demonstrating the validity of the proposed
scheme, a wide range of uncertainties in the dynamic parameters of a nonlinear
power system were tested. In addition, a comparative study is presented between
the results obtained from a classical integral, CDM alone, optimized Fuzzy,
optimized PID, and the suggested controller. In this new approach to improved
control, algebraic support provides a robust and responsive controller that can
provide fast and stable dynamic responses and effectively overcome the
detrimental effects of nonlinearities and uncertainties in the parameters of
the power system.
