1.School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044, China;2.Key Laboratory of Ministry of Education on Smart Power grids (Tianjin University), Tianjin 300072, China

The wide application of flexible interconnection devices makes the operation of active distribution networks more controllable and flexible. This paper proposes a cooperative planning scheme of soft open points and energy storage devices for balancing the energy distribution in distribution networks with source-load imbalance characteristics in order to improve the economy and reliability of distribution networks. First, considering that the distributed generator output has uncertainty, the K-means method is used to construct a typical-day scenario, based on which a cooperative planning model is established with the minimum annual comprehensive cost as the objective function. Then, the original nonlinear nonconvex model is transformed into a mixed-integer second-order cone planning model by the big-M method and second-order cone relaxation techniques, and a two-stage distributionally robust model with integrated paradigms is used to find the planning scheme that can obtain the lowest operating cost under the probability distribution in the worst scenario in order to improve the robustness of the planning model. Finally, the feasibility of the proposed planning model is verified through the case with two source-load imbalanced IEEE 33-bus active distribution networks.