高比例新能源的接入对系统的稳定性提出了挑战，针对采用异步联网的直流送端系统，研究其在高新能源占比下保障直流通道的大容量稳定外送具有重要意义。引入系统电压与频率支撑能力，以最大化系统外送能力与新能源消纳能力、最小化电压支撑能力失衡度为优化目标，建立了基于送端系统支撑能力调整的直流外送能力优化模型。将模型求解分为主、子两个问题，采用基于改进多目标粒子群算法的IMOPSO-PSD联合优化仿真算法对模型进行求解，通过变异系数法在计及电压支撑能力失衡度的基础上筛选出最优运行方式。最后，以高新能源占比的IEEE 39节点异步直流送端电网为例验证了所提方法的有效性。

The access of high proportion of new energy poses a challenge to the stability of the system, and it is of great significance to study the DC feeder system with asynchronous networking to ensure the large-capacity and stable transmission of the DC channel under the proportion of new energy. Introducing system voltage and frequency support capabilities, with the optimization goal of maximizing system external transmission capacity and new energy consumption capacity, and minimizing the imbalance of voltage support capacity, the DC external transmission capacity improvement optimization model based on the optimization of the sending-end system support capacity is established by introducing the system voltage and frequency support capacity. The model is divided into main and sub-problems, and the IMOPSO-PSD joint optimization simulation algorithm based on the improved multi-objective particle swarm algorithm is used to solve the model, and the optimal operation mode is screened out by the coefficient of variation method taking into account the imbalance of the voltage support capacity. Finally, the effectiveness of the proposed method is verified by taking the IEEE 39-node asynchronous DC sending-end grid model with high proportion new energy as an example.