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Summary Automatic generation control of the unequal 3‐area system with diversified sources like small hydrothermal units in area‐1 and area‐2 and split shaft gas turbine thermal units in area‐3 with nonlinearity of generation rate constraint is explored. A cascade combination of integer order integral‐derivative with filter (IDN) and fractional order proportional derivative (FOPD) is considered as a secondary controller (IDN‐FOPD). The controller gains and other parameters are optimized using whale optimization algorithm. The performance of IDN‐FOPD controller has an upper hand when compared with some classical controllers like integral, proportional‐integral, and proportional‐integral‐derivative with filter (PIDN). Analyses reveal that the performance of a combination of IDN‐FOPD in area‐1 and PIDN controllers in other areas of system dynamics provides comparable results with IDN‐FOPD controllers in all areas. Thus, this combination of controllers is carried for further analyses. Even eigenvalue analysis has been performed for analyzing system stability. The impact of time delay on system dynamics is also studied. The impact of the inclusion of renewable source like a solar thermal power plant in area‐1 and electric vehicles in all areas provides better system dynamics in the presence of nonlinearity generation rate constraint and time delay. Sensitivity analysis reveals that controller gains and other parameters obtained at nominal conditions are robust to changes in variable solar insolation and demands no further reset.

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The present article deals with automatic generation control of a three-area multi-source thermal-gas (T-G) system with integration of distributed generation (DG), electric vehicles (EVs), and energy storage devices. Each thermal unit is equipped with a single reheat turbine, a generation rate constraint, and a governor dead band. A cascade combination of two degree of freedom proportional-integral-derivative with a filter (2DOF-PIDN) and a fractional order integrator controller [(2DOF-PIDN)-FOI] is proposed as the secondary controller for the system. A meta-heuristic algorithm, whale optimization algorithm, is utilized for simultaneous optimization of gains and other parameters of controllers PIDN, PIDN-FOI, and (2DOF-PIDN)-FOI. Critical observation reveals the superiority of the latter in terms of peak deviations and settling time (ST) for the T-G system under both step load perturbation and random load perturbation. Eigen value analysis is also performed for the T-G system with and without secondary controllers. Analyses show noticeable improvement on the T-G system with incorporation of both DG and EV. Investigations infer that combined involvement of energy storage devices like ultra-capacitors and superconducting magnetic energy storage devices along with DG and EV leads to better performance regarding the reduced peak deviations, magnitude of oscillations, and settling time for the T-G system. Moreover, sensitivity analysis reveals that (2DOF-PIDN)-FOI controller parameters obtained at nominal conditions are robust and there is no need to reset again with a wide variation of system parameters like the inertia constant and area participation factor and system conditions like loading and disturbance.

Summary The current work deals with the study of unequal multi‐area automatic generation control under a restructured environment. Each area has two generating companies (GENCOs) and distributing companies (DISCOs). The GENCOs in area‐1 are wind power plant and thermal unit and area‐2 are split shaft gas turbine and thermal unit. A fresh step is made to utilize a cascade aggregate of integral‐order and fractional‐order controllers named as integral derivative along with filter and proportional derivative secondary controllers (IDN‐FOPD). Analysis of IDN‐FOPD controller performance is compared with commonly used classical controllers. Investigation reveals the superiority of IDN‐FOPD controller. The controller gains, as well as other parameters, are obtained by applying the whale optimization algorithm. Few flexible AC transmission system devices like static synchronous series compensators, thyristor controlled series capacitor, and interline power flow controllers (IPFC) are also incorporated one at a time using an IDN‐FOPD controller. Comparative analysis reveals the better performance of IPFC. Analysis has been done for proper selection of a gain of ultra‐capacitor (UC). Energy storage devices like UC and both UC and redox flow battery (RFB) are integrated to examine the effect on system dynamics and reports better performance of UC and RFB. Sensitivity analysis reveals the robustness of IDN‐FOPD secondary controller's gains plus other parameters for varied DISCO participation matrix.