Detailed and Average Battery Energy Storage Model Comparison

In this paper, a comparison between detailed and average Battery Energy Storage System (BESS) models is presented for power system applications. The BESS models are first studied connected to an infinite bus and its dynamic response to step changes and system disturbances are compared, highlighting the limitations of the average model with respect to the detailed model. Then, both models are used to represent distributed BESSs connected at the load buses of the WECC 9-bus test system to provide primary frequency regulation, comparing their performance. It is concluded that the average model does not properly capture the BESS performance for frequency regulation applications when limits are reached; furthermore, it is shown that the frequency regulation of the system can be considerably improved by small-size BESSs.