Optimal Operation of BESS for Maximum Use of Its Energy in Power System Load Frequency Control Considering Economic and Technical Objectives

The primary objective of this study is to propose a methodology for setting the frequency of an automatic generation control system when integrating battery energy storage systems (BESS) and wind turbines. The introduced approach leverages an energy management system (EMS) designed to minimize the operational costs of thermal units while optimizing the state of charge (SOC) levels within BESS. This EMS framework ensures optimal energy distribution between thermal units and BESS across different areas of the power system, enhancing SOC management and reducing associated fluctuations. To mitigate inter-area power system fluctuations, a linear quadratic controller (LQC) is employed to adjust the zero points of the proportional–integral (PI) controller finely. This two-level design begins by minimizing the state errors of the PI controller through the integral squared error approach, followed by the application of LQC as an upper-level controller to optimize the PI setpoints. Given the challenge of limited state variable availability due to measurement noise, a Kalman filter is utilized to estimate these unmeasured states. The objective functions of the EMS for economic operation and frequency adjustment are optimized using the firefly algorithm implemented in MATLAB.