A Comparison of Optimal Control of AGC for Hydrothermal System using Local Optimization

This work is mainly focused on Automatic Generation Control (AGC) of an interconnected hydrothermal system in continuous and discrete mode. Initially, the conventional controllers such as Proportional Integral Derivative (PID) of linear controllers were tuned with different tuning approaches such as direct search algorithm. Finally, those results are compared with the PI controllers. Optimal control strategies have been taken as Integral Square Error (ISE), Integral Time-Absolute Error (IATE) and Integral Time Square Error (ISTE). The simulation results indicate that better control performance regarding overshoot, settling time can be obtained by a direct search algorithm. For the given plant's appropriate generation rate constraints (GRC) has been considered both for the thermal and hydro plants. System performance is examined considering 1% step load performance (SLP) in both thermal and hydro area with 1 second sampling period. Investigations reveal that the performance of the direct search for tuning the controller parameters, at the same time the performance of the PID controller is better than the conventional controller of PI.