Abstract: Considering the reliability and safety indexes of the regional power grid, a capacity configuration method of pumped storage to improve the carrying capacity of new energy is proposed. Firstly, the measured output data of wind farms and photovoltaic power stations are analyzed. Copula theory and K-means clustering generate typical output scenarios considering the correlation between wind power and photovoltaic generation. Secondly, a capacity configuration model of pumped storage for improving the new energy-carrying capacity of the regional grid is established. With the constraints of loss of load probability and expected energy not supplied index, the regional grid's maximum new energy carrying capacity is evaluated based on typical wind and photovoltaic output scenarios. Combined with the pumped storage operation model, the new energy-carrying capacity is improved by configuring the minimum installed capacity of pumped storage. Finally, the voltage over-limit risk and the power flow over-limit risk index are used as the safety check, and the probabilistic power flow is used to analyze the operation risk of the regional grid. The analysis results of the improved IEEE-39 node system show that the proportion of new energy-carrying capacity can be increased to 64% by configuring pumped storage.