In recent years, power systems have experienced rapid transformations, particularly in terms of generation resources. These changes have significantly impacted the response characteristics of frequency control structures. In response, system operators have been compelled to augment frequency control reserves, diversify markets, and seek support from various generation sources. Ancillary services, such as Automatic Generation Control (AGC), have emerged as crucial elements in this regard. Motivated by this context, this study focuses on integrating AGC into a dynamic model, building upon the static model of the Turkish transmission grid. Following this integration, the performance of a Proportional-Integral (PI) controller within the AGC framework is evaluated under changing system conditions. The analysis indicates that employing a value of 0.1 for K p and 60 for K i yields the best AGC performance within the current system state. Thus, the paper underscores the significance of AGC integration and parameter optimization in enhancing frequency control efficacy amidst evolving power system dynamics.