Multi-timescale modeling of battery energy storage system and its application in wind power balance

The battery energy storage system (BESS) model based on Thevenin equivalent circuit is developed in this paper. Considering the variations in model parameters with SOC and charge/ discharge current, the parameter fitting methods based on manufacturers´ and experiment data are introduced. The effectiveness of the proposed model is verified by comparing with the measured voltage and current profiles. Further, in the range of different power system application scenes, the model is simplified to be respectively feasible for short term and long term simulations, thus the multi-timescale model of BESS is derived. Applying this model to alleviate wind power midterm and long term volatility, simulations are performed to test the control effect of BESS. The influence of different models on BESS capacity allocation is compared to further analyze the advantages and disadvantages of the models.