1.Key Laboratory of Control of Power Transmission and Conversion, Ministry of Education (Shanghai Jiao Tong University), Shanghai 200240, China;2.College of Information and Electrical Engineering, China Agricultural University, Beijing 100083, China;3.Xiamen Power Supply Company of State Grid Fujian Electric Power Co., Ltd., Xiamen 361000, China;4.Energy Research Institute of China Southern Power Grid Co., Ltd., Guangzhou 510663, China

The temporal-spatial variation of traffic flow leads to changes in the distribution of electric vehicle charging demand, which further affects the electric vehicle hosting capacity in the distribution network. In order to elaborately consider the influence of traffic flow, a calculation method for the electric vehicle hosting capacity in the flexibly interconnected distribution network (FIDN) considering traffic flow is proposed. This method considers the flexible adjustable ability of the soft open point to reduce the adverse effect of large-scale electric vehicle integration on distribution networks. Firstly, based on semi-dynamic traffic flow model, a regulation model for electric vehicles with various integration modes is established. Secondly, considering the regulation measures of electric vehicles under the influence of traffic flow, a calculation model for the electric vehicle hosting capacity in FIDN considering traffic flow is proposed to maximize the number of electric vehicles that can be carried. Then, the model is transformed by the quadratic convex relaxation method, the big-M method and the second-order cone relaxation method. To reduce the relaxation gap, a nested tightening relaxation algorithm is proposed to solve the model. Finally, the validity of the proposed model and algorithm is verified by the test and analysis in the modified standard case and an actual case in Fujian Province of China.