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柔性直流环节的引入有望提高配电网的潮流调控能力.提出一种直流环节对配电网优化运行作用的概率评估方法.在分析直流环节稳态特性的基础上,建立含直流环节的配电网随机优化潮流模型.由风电、光伏的离散概率模型构造多个分布式电源出力确定的条件概率分布问题.针对每个条件事件,结合粒子群寻优算法和半不变量解析法对所提出的模型进行求解,再应用全概率公式进行累加拟合,可得到计及直流环节调控作用的随机变量完整概率分布.采用IEEE 33节点算例在不同场景下进行了仿真分析,测试结果表明直流环节对配电网优化运行(尤其是分布式电源高渗透率条件下)具有积极作用,提出的方法对直流环节接入交流配电网规划具有理论和实际意义.“,”The access of flexible DC link will be helpful to improve the power flow control ability of distribution network. This paper proposes a probability-based method to evaluate the benefits of flexible DC link for optimal operation distribution network. The probabilistic optimal power flow model (P-OPF) of distribution network with DC link was established using the steady-state model of DC link. The probabilistic models of distributed generators (DG) output were discretized to construct multiple conditional probability problems with the certain power injection of DG. The P-OPF model was solved in each conditional event based on particle swarm optimization algorithm and cumulant-based analytic method. The full probability distributions of stochastic variables in optimized operation were obtained by accumulating all Gauss functions of conditional events according to the total probability formula. A case study of modified IEEE 33-bus test system was carried out in different scenarios. Results show that the flexible DC link plays an active role on the optimal operation of distribution network, especially with high penetration of DG. The proposed method has theoretical and practical significance for the access planning of DC link in a distribution network.