Transmission level PV plants have become a reality in recent years for encouraging more renewable energy. Large-scale PV plants can provide clean, affordable and sustainable electricity to the grid. However, they also introduce negative impacts as a result of intermittent power output and zero inertia characteristics. Hence, PV plants need an auxiliary device to overcome these concerns. One of the auxiliary devices that becoming favorable in recent years is Battery Energy Storage (BES). BES can provide fast response in providing constant active power to the grid or storing energy from PV plant along with a number of other capabilities. This paper investigates the influence of BES system installation at large-scale PV plant on small disturbance angle stability of interconnected power system. Analysis of sensitive eigenvalues, damping ratio, and phase portrait are carried out to investigate the impact of utilizing BES system in large-scale PV plant. From the simulation results, it was found that installing BES system in large-scale PV plant has significant influence in EM mode and BES system capacity also has a contribution in the dynamic behavior of the system.