Coordinated Planning of Charging Stations and Distribution Networks with V2G Interaction and Line Capacity Margin Considerations

To address the transmission congestion problem in urban distribution networks caused by concentrated charging of large-scale electric vehicles (EVs), this paper proposes a coordinated planning method integrating charging stations and distribution networks, which incorporates vehicle-to-grid (V2G) energy storage characteristics and line capacity margins. First, a dynamic traffic network model is established to accurately simulate EV travel routes and obtain spatiotemporal distribution of charging loads based on user equilibrium assignment principle. Second, building upon EV load forecasting results, the proposed method determines optimal locations and capacities of charging stations with dual objectives of minimizing integrated costs and maximizing V2G energy storage capacity. Subsequently, a coordinated planning model considering coupling relationships between transportation and distribution networks is developed, which conducts distribution network expansion planning aiming to minimize comprehensive costs and standard deviation of grid line capacity margins. The normalized normal constraint method is employed to handle the multi-objective optimization problem across two hierarchical layers. Finally, case studies based on actual urban traffic network and a 54-node expandable distribution network demonstrate the effectiveness of the proposed methodology.