Stellar Oscillation Optimizer Based Combined Automatic Voltage Regulation and Load Frequency Control of Two Area Power System

This study proposes a new approach for the combined automatic voltage regulator (AVR) and load frequency control (LFC), called the stellar oscillation optimizer (SOO) method. Due to the dynamic nature of power systems, the goal is to ensure both frequency and voltage stability under varying load conditions. The proposed SOO method was tested on a two-area power system containing thermal generation units. In the combined LFC-AVR model, four different PID controllers were used to provide two LFC controllers and two AVR controllers. The optimal gain values of these PID controllers were optimized using the integral of time multiplied by squared error (ITSE) objective function. The performance of the proposed SOO algorithm was compared with the nonlinear threshold accepting (NLTA) and multi-objective nonlinear threshold accepting (MONLTA) methods from the literature. Comparative analysis revealed that the NLTA method achieved an ITSE value of 4.4143, the MONLTA method achieved 4.1695, whereas the proposed SOO method attained a significantly lower ITSE value of 2.8938, demonstrating superior frequency and voltage stability. These results indicate that the SOO method can be an effective and reliable alternative solution for improving LFC and AVR control in complex multi-area power systems.