Optimal design of a cascade controller for frequency stability of photovoltaic–reheat thermal power systems considering nonlinearities

Abstract Automatic generation control (AGC) is essential for raising living standards because it enhances power supply quality. However, due to the constraints and challenges experienced in practice, an effective computationally economical method necessary improve AGC performance, particularly presence of renewable energy. Therefore, this study introduces a novel cascade controller (CC) proportional–integral–derivative (PIDn) followed by proportional–integral (PI) controller, forming PIDn-PI CC. This used two-area model comprising reheat thermal generator photovoltaic unit. The gains PI, PIDn, controllers are adjusted using recently introduced chaos game optimization (CGO), which minimizes objective function integral time multiplied absolute error. CGO relies on theory principals, wherein organization fractal geometry perceived through chaotic fractals’ self-similarity properties considered. At first, based PIDn employed, check suitability dealing with problems. Furthermore, several scenarios confirm effectiveness CGO:PIDn-PI scheme when subjected high load disturbance uncertainty, can change system parameters ± 50%. A random pattern ascertain proposed method’s efficacy. Finally, nonlinearities, such as rate constraint delay, have significant impact Compared relevant current research, suggested approach outperforms them terms settling time, frequency, tie-line deviations.