Optimal FOPID controller design for LFC of power system via model order reduction

Abstract This paper presents the design of a load frequency control (LFC) scheme for a single-area higher-order thermal–hydro–gas power system model (HOTHGPSM) using a fractional order proportional integral derivative (FOPID) controller. To simplify the controller design process and reduce computational complexity, a model order reduction approach is employed. Instead of directly designing the controller for the original higher-order system, a reduced-order model (ROM) that preserves the dominant dynamic characteristics of the system is developed and utilized for controller synthesis. The ROM is obtained using a hybrid order reduction technique based on time moments, Markov parameters, and the Routh–Hurwitz array. The parameters of the FOPID controller are optimally tuned using the grey wolf optimization algorithm. Subsequently, the designed controller is implemented on the original HOTHGPSM. The excellent agreement between the responses of the reduced-order and original systems confirms that the proposed model reduction method accurately captures the dominant system dynamics, enabling efficient controller design without compromising control performance.