Improvement of Transient Stability Limit Using Battery Energy Storage Systems and STATCOM

Flexible ac transmission systems (FACTS) devices are commonly used in power systems to improve the dynamic and static performances of the system. Battery energy storage systems (BESS) are now increasingly being installed in modern power systems for energy arbitrage and ancillary services. This paper describes a technique to improve the transient stability limit of a simple power system using a BESS. A previously developed control strategy to improve stability using STATCOM is applied to control the BESS. The strategy is based on a combination of the maximum and continuous current control. The stability limit, and hence the critical clearing time, obtained using BESS is compared with that obtained using STATCOM. A classical model of the system has been implemented in Matlab Simulink and DIgSILENT PowerFactory software for the analysis. Further analysis has been conducted for a higher order machine model implemented in PowerFactory. The investigations revealed that the BESS is more effective in enhancing the stability limit of the system compared to a STATCOM of the same current rating for both classical and higher order machine models.