AGC of a multi-area thermal system under deregulated environment using a non-integer controller

Abstract

This paper presents automatic generation control (AGC) of multi-area thermal systems under deregulated environment considering reheat turbines and appropriate generation rate constraints (GRC). The performance of a fractional-order Proportional–Integral–Derivative (FOPID) controller is evaluated for the first time in AGC of the proposed systems. Performances of several integer order (IO) controllers have been evaluated and are compared with FOPID controller. Investigation reveals that FOPID controller provides better dynamic performance than the IO controllers in both equal and unequal area system. Bacterial foraging (BF) technique is used for simultaneous optimization of the gains and other parameters such as order of integrator (λ) and differentiator (μ) in case of FOPID controller and speed regulation parameter (R) and such optimization results higher value of R which is welcome for simple and cheaper realization of governor. Further, Sensitivity analysis is carried out for the first time in the system considered to investigate the robustness of the optimum gains, λ and μ of FOPID controllers and R parameters obtained at nominal condition. Analysis expose that parameters obtained at nominal conditions need not be reset to wide changes in system condition, parameters, size and position of step load perturbation (SLP). Investigations on higher order of contract violation reveal that FOPID controller performed better than other IO controller.