Smith Predictor Based Fractional LFC Strategy for Storage Supported Thermal Power System Amid Communication Dead Time and Cyber Threats

Communication dead time (CDT) amid integration of renewable energy sources (RESs) and energy storage systems (ESSs) into modern power system networks can result in instabilities, phase lags and sluggish corrective action when dealing with frequency and tie-line power deviations. To compensate CDT, a Smith predictor based Fractional Order Proportional-Integral-Derivative with Integrator (FPIDI) controller is analytically designed for a dual-area thermal power system (TPS) with integrated RES, battery ESS, flywheel ESS and Ultra-capacitors. The FPIDI controller is designed using a modified internal model control (IMC) theory that is based on the frequency-relocated fractional-order model of the TPS. This modified IMC method eliminates the need of phase-lag inducing IMC filter. The performance-robustness tradeoff is enhanced by appropriate selection of the single tuning parameter (frequency-relocation factor (ψ)) by minimizing the integral of time-weighted absolute value of area control errors. The proposed controller is validated both by simulation and hardware-in-loop implementation to show its practical feasibility.