Abstract: This paper presents a function of load frequency control (LFC) in single and two interconnected power systems. It is based on PSO concept. It presents Load Frequency Control problem related to single-area and two-area power systems is studied for uncontrolled case and then with the application of the integral controller, PSO based controller using MATLAB SIMULINK/Workspace software. In case of a single-area system, under uncontrolled case, steady state frequency error exists. The integral controller improves the systemís dynamic performance by removing this steady state frequency error. In case of two-area power system, integral controller is used in both the areas to overcome systemís steady state frequency errors and thereby enhancing systemís dynamic performance. The integral controller is optimized using PSO based controller and is shown that the PSO based integral controller provides better dynamic performance than integral controller in terms of lesser settling time and peak overshoots. Then a PSO based PI controller is developed to control two-area power systems.

Keywords: PSO, Load Frequency, Single Area, Multi Area System etc.