Automatic generation control of a multi-area CCGT-thermal power system using stochastic search optimised integral minus proportional derivative controller under restructured environment

This article presents automatic generation control of an interconnected combined cycle gas turbine (CCGT) incorporated unequal area thermal system under restructured environment. Investigations have been carried out with two generating companies and two distribution companies in each area. Area 1 includes CCGT-thermal system and area 2 includes thermal-thermal system. Both areas are employed with appropriate generation rate constraint (GRC) and governor dead band in thermal systems. Integral minus proportional derivative with first-order filter effect (I-PDF) controller is used as secondary controller whose promising performance is compared with proportional, proportional integral and proportional integral derivative controller. The controller gains and other parameters are optimised using stochastic fractal search (SFS) algorithm. Sensitivity analysis is performed with change in system loading, system parameters such as inertia constant, governor and turbine time constant and random load disturbances to evaluate the robustness of proposed SFS optimised I-PDF controller. The simulation results with different set of contractual agreement postulated by DISCO participation matrix and its violation illustrates the effectiveness of SFS optimised I-PDF controller. Additionally, the system under restructured regime is investigated with combinatorial increment in GRC and delayed controller action for appropriate use and maintenance of the proposed controller.