Adaptive T2FPID Controller for Load Frequency Control in a Nonlinear Time-delay Power System

In this paper, an adaptive T2FPID controller is designed for load frequency control (LFC) in a nonlinear, uncertain and time-delay power system. The time-varying delay at the input of the power system that is mainly due to the signal processing, filtering, calculations and breakdown in the communication channels in most cases may lead to system instability. The designed T2FPID controller is a nonlinear and adaptive controller and is able to handle the nonlinearities, uncertainties and time-varying delay at the input of the power system. An appropriate Lyapunov-Krasovskii functional has been used to examine the stability of the closed loop system and to obtain the adaptive rules for the T2FPID controller. Using this functional, it has been shown that the frequency deviations in the control areas have reached to zero and the adaptive parameters of the controller remain bounded. To demonstrate the efficiency of the proposed method, a two-area nonlinear input delayed power system (with four generation and distribution companies) is used for simulations and it is shown that the proposed control strategy outperforms other methods in terms of overshoot and settling time.