Abstract:This paper briefly introduces the advantages and characteristics of urban DC power distribution system. This paper introduces several kinds of urban DC distribution systems such as "point-to-point" flexible DC distribution system, radiation-type DC distribution network, "hand-hand" DC distribution network and Zhuhai three-terminal flexible DC distribution network. On the basis of summarizing the advantages and disadvantages of the topology of DC distribution system above, a kind of urban DC distribution system topology with multi-mode, medium-and low-voltage, AC-DC mixing and access to various distributed energy sources is designed and applied to the DC distribution demonstration project in Guizhou city. The characteristics, voltage class, operation mode, efficiency and extensibility of the topology are introduced, and it is pointed out that the topology can be used to study the distributed energy of DC distribution system. The comparison of energy efficiency and flexibility of operation mode of AC and DC distribution has significant advantages. Through the self-developed intelligent distribution network semi-physical simulation platform, the simulation of arbitrary flexible interconnected AC and DC distribution network is realized, which solves the problem that DC distribution network needs to be repeated as a demonstration project application research..