Dynamic Response of Load Frequency Control Using a Proportional Integral Derivative (PID) Controller

Load Frequency Control (LFC) plays a crucial role in maintaining power system stability by regulating frequency deviations and tie-line power flows following load disturbances. In this study, the performance of a Proportional–Integral–Derivative (PID) controller is evaluated and compared with other classical controllers (P and PI) in thermal– thermal, thermal–hydro, and multi-area interconnected systems. The analysis focuses on key performance indices, namely overshoot, rise time, and settling time. Results show that the PID controller generally enhances dynamic response by reducing settling time and improving damping characteristics, particularly in hydro and hybrid systems where settling time is minimized to 27.93 s and tie-line power deviations are significantly reduced compared to the uncontrolled case. However, in thermal–thermal systems, PID control sometimes amplifies overshoot (e.g., 0.06205 pu compared to 0.005524 pu without control), highlighting its sensitivity to tuning. Comparatively, PI controllers offer more balanced improvements in both frequency and tie-line power stabilization, while proportional control excels in reducing rise time but may worsen settling performance in certain cases. These findings align with previous studies that emphasize the superior performance of PID controllers in complex and hybrid networks due to their combined proportional, integral, and derivative actions, but also confirm observations in literature that improper tuning can degrade performance in purely thermal systems. The comparative analysis underscores the importance of controller design and parameter optimization in LFC applications and demonstrates that while PID offers the most versatile performance, PI control remains a reliable alternative for ensuring consistent stability.