Comparison of Battery Energy Storage Models for Small Signal Stability in Power System

In the 21st century, integration of large-scale renewable energy sources (RESs) is increasing significantly. Although RESs provide clean and sustainable energy, they may adversely affect the performance of power system due to their distinct dynamic characteristics and intermittent power output. It is apparent that the integration of battery energy storage system (BESS) in power system is inevitable to accommodate more RESs. BESS could provide additional active and reactive power to the grid to overcome the energy shortfall. It is reported that the dynamics associated with BESS may significantly influence the low-frequency oscillation of the system. Therefore, it is important to analyze the various models of BESS for power system small signal stability studies. This paper investigates various models of BESS and their impacts on low-frequency oscillation for high penetration of RESs. Analysis has been conducted using Two-area power system for which the benchmark results are available for comparison purpose. Both the eigenvalue and time-domain analyses are employed in this paper to assess the impacts of various BESS models on low-frequency oscillation. From the simulation results, it is evident that the detailed model of BESS (i.e. 5th order model) could reflect the complete influence of BESS controller on low-frequency oscillation.