Maiden application of two degree of freedom cascade controller for multi-area automatic generation control

In this article, a 2 degree of freedom cascade controller (2DOF-CC) is presented as the supplementary controller (SC) for multi-area hydro-thermal system. Proposed 2DOF-CC is the combination of 2DOF proportional-integral-derivative (2DOF-PID) and 2DOF proportional-derivative (2DOF-PD) controllers. The gains and other parameters of various controllers like PID, 2DOF-PID, and 2DOF-CC are optimized with cultural algorithm when considered one at a time. Comparison of dynamic responses of the system for PID, 2DOF-PID, and 2DOF-CC reveals better performance of the latter in terms of settling time and magnitude of oscillations. The study is also extended by incorporating superconducting magnetic energy storage units and explored that superconducting magnetic energy storage units effectively suppress the system dynamics against both step and random perturbations in presence of 2DOF-CC. Selection of governor speed regulation parameters (R) and frequency bias parameter (B) in the presence of 2DOF-CCs have been done in the considered system. Investigations recommend the use of higher values of R, and B should be kept at area frequency response characteristics (). The effect of double reheat turbines on system response is also investigated and reveals that use of double reheat turbines deteriorates the system responses. Sensitivity analysis validates the sturdiness of parameters of 2DOF-CC obtained at nominal conditions.