Abstract: Power grid connected with large capacity photovoltaic(PV)will influence distribution network and PCC(point of common coupling)voltage fluctuation, so PV power station equipped with appropriate capacity of energy storage system can reduce PCC voltage fluctuation of PV power station. In the paper, the RTDS(real time digital simulator)model of power generation system connected with energy JP3storage and PV system is built, through which the cases on varying light intensity, different ambient temperature and the change of adjacent load are simulated, and the comparison of varying effective value of power and voltage is analyzed under such conditions as power system with/without energy storage. According to the standard deviation of the voltage effective value, quantitative study on the reduction of PCC voltage fluctuations is carried out. The simulation results show that the energy storage system can effectively restrain the voltage fluctuation of PV power system and reverse power operation, and can improve the JP3power quality. In addition, there is larger PV power output, and effect of storage system on restraining PCC voltage fluctuation is more obvious. The study results can provide reference for reducing PCC voltage fluctuations of new energy sources and the development of large scale power system with PV and energy storage.