Modeling and Simulation of Battery Energy Storage System (BESS) Used in Power System

For reflecting grid connected operation control strategies, modeling of Battery Energy Storage System (BESS) was studied. The BESS models include two parts according to the infection to control results of State of Charge (SOC) of batteries. One is the electromechanical transient model, and the other is the long-term dynamic model. The convertor section of the models consider power control segment in normal operating mode, and fault crossing and protection segment reflecting output external characteristics in abnormal operating mode. In the capacity limit aspect, the actual voltage-SOC curve of battery is introduced in the models. Meanwhile, the charging and discharging characteristics can be simulated accurately. The validity of the proposed models is proved according to calculation results after taking BESS models into single generator system for simulation. In this paper, BESS models are established from the perspective of power grid and to realize the target of grid connected control, the models have generality, and they are suitable for electromechanical transient and long-term dynamic simulation. Therefore, the problems of present BESS models, that is being complex, reflecting charging / discharging characteristics of different batteries but no grid connected characteristics, and being not suitable for engineering application, can be solved.