Abstract: With the connection of large-scale wind turbines and the replacement of conventional synchronous generators in a sending-end power grid, the short circuit ratio level of the grid decreases, and the voltage support ability is weakened. A fault can easily result in transient overvoltage of new energy generators and cause off-grid accidents. This paper studies the optimal configuration method of synchronous condenser for the sending-end power system with a high renewable penetration level, considering the short-circuit ratio improvement and transient overvoltage suppression. Firstly, the condenser's access improvement effect on the wind farm's short-circuit ratio is analyzed using the multiple renewable energy stations' short-circuit ratio (MRSCR). Based on the condenser's fast reactive power response characteristics, its influence on the transient overvoltage of the wind turbine is revealed. Then, a two-stage optimal configuration strategy for the condenser is proposed to consider both short-circuit ratio improvement and transient overvoltage suppression. In the first stage, the core constraint of wind farm short-circuit ratio improvement is considered to optimize the position and basic capacity of the condenser. In the second stage, the obtained capacity is corrected based on the key constraint of transient overvoltage safety, and the quantum genetic algorithm (QGA) is introduced to optimize the solution. Finally, based on the analysis of PSD-BPA in a sending-end power grid with a high proportion of wind power, it is verified that the proposed condenser configuration method can significantly improve the MRSCR and effectively suppress the transient overvoltage of wind turbines.