Identification of fractional order PI controllers ensuring desired gain and phase margins for a time-delayed single-area load frequency control system with demand response

This research presents a load frequency control (LFC) system with demand response (DR) studied for robust stability analysis based on gain and phase margins (GPMs) utilizing a fractional-order proportional-integral (FOPI) controller. Electric power systems contain many parametric uncertainties. FOPI controller gains are adjustable parameters and can be designed to provide the desired frequency control and dynamic performance. Therefore, in this article, the robust stability regions containing a set of robust FOPI controller gains are designed for the range model of the load frequency control system using Kharitonov’s theorem, considering the uncertainties in the LFC-DR system parameters and the time delay. Further, the robust performance of the interval LFC-DR system in terms of design features, including GPMs, is investigated. Simulation studies indicate that GPM parameters provide a better dynamic performance in terms of fast damping of oscillations, less settling time, and overshoot time for the interval LFC-DR system.