One location that has the potential to build a solar power or PV Farm is at Nusa Tenggara Timur (NTT) system in the year of 2023. Thus, in-depth study will be needed to make sure the PV Farm penetration can be done without giving any negative impact to the NTT system stability. The main objective of this study is to evaluate the impact of the PV Farms penetration while taking into account the addition of battery system that works in frequency-smoothing mode or load-shifting mode.