A fault happening on an HVDC sending-end system with a high-proportion of renewable energy may lead to renewable energy transient overvoltage tripping. Configuring distributed synchronous condensers in renewable energy stations or collection stations is an effective means for restraining transient overvoltage. In view of the technical requirement for optimal configuration of distributed synchronous condensers, this paper first analyzes transient overvoltage propagation characteristics of the HVDC sending-end system. Based on this, the candidate node selection method of condenser considering the comprehensive transient voltage rise severity index of node and system is proposed. Then, taking into account the optimization goal of minimizing the operational and maintenance costs of the condenser, considering transient voltage stability constraints under multiple scenarios and multiple faults, the optimal configuration model of the distributed synchronous condensers is established. Finally, the optimal configuration scheme is obtained by using a particle swarm optimization algorithm, and a high-proportion of renewable energy DC transmission test system is established. The effectiveness of the proposed configuration method is verified by BPA-PYTHON-Matlab joint simulation. This work is supported by the Science and Technology Project of the Headquarters of State Grid Corporation of China (No. 5100-202136012A-0-0-00).