AGC of a multi - area system using firefly optimized two degree of freedom PID controller

This paper presents the automatic generation control (AGC) of an interconnected three unequal area thermal system with appropriate generation rate constraints and governor dead band. The areas are provided with single reheat turbine. The system dynamic performance is evaluated by considering 1% step load perturbation (SLP) in area1. The firefly algorithm (FA) is used for optimization of secondary controller gains and other parameters. The performance of the two degree of freedom PID (2DOF PID) controller is evaluated for the first time in AGC of three area system and compared with that of conventional single degree of freedom PID controller (simply PID controller). Additionally, the 2DOF PID and PID controllers are tested for different loadings and SLPs. Investigations reveal that the performance of 2DOF PID controller is much better than PID controller. Also, it is seen that the control performance of 2DOF PID is better and improves with wide change in loading and SLP from their nominal values.