The power system is gradually moving toward a high percentage of renewable energy power grid due to the rapid development of renewable energy sources like photovoltaic and wind power. In many places, the high percentage of renewable energy access to the power system weakens the system's ability to handle voltage, creating a fragile power grid. The ensuing system's frequent local broadband fluctuations and renewable energy off-grid are pressing issues that require attention. In the AC system, the condenser is the perfect reactive power compensation device because of its excellent dynamic characteristics. In this study, a large percentage of renewable energy power system is the research object. Considering the short-circuit ratio index constraint and considering the power flow constraint, the optimal configuration of condenser is completed by iterative algorithm. Finally, the effectiveness of the proposed method is verified based on PSD-BPA in IEEE39 node system.