A Distribution Network Flexibility Evaluation Method Based on Maximum Flow Algorithm

Due to the integration of vast quantities of fluctuant clean energy, the demand for flexibility in distribution network is increasing greatly. However, current studies on flexibility mainly focus on the balance between total supply and total demand, which lacks comprehensive consideration of network topology and electrical characteristics. A novel evaluation method based on maximum flow algorithm for network flexibility is proposed in this paper. First, the flexibility resources (FR) model of node and network are presented. Then, the maximum flow method, in which the current power flow is chosen to build the directed flow graph, is employed to calculate the network flexibility indicator (NFI) for both the spatial and temporal distribution characteristics. Finally, by a comprehensive case study, the detailed spatial and temporal distribution characteristics of NFI are analyzed and compared. The results show that the flexible interconnection device (FID) can enhance NFI while the total amount of FR unchanged, but the improved effect is not the same for all the nods and all the time. And the proposed method could describe more detailed information of NFI about the location and the time. Furthermore, the presented evaluation method has much faster computation than the traditional optimization method and the accuracy of the method is also verified.