Research On Reliability Of Flexible DC Distribution System

In recent years, DC distribution system already become a research hotspot, it can improve the power supply capacity, improve power quality, accept DC load and distributed power easily.Different from traditional AC distribution system, DC distribution system is mainly made up of a lot of power electronic devices, and can work with several power supply, so the reliability assessment of DC distribution system is different from AC distribution system. In order to better assess the reliability of flexible DC distribution system, and provide practical advice to flexible DC distribution system planning, the reliability of medium-voltage flexible DC distribution system in depth is studied in the paper. The factors that affect the reliability of AC distribution system are analyzed and improvement measures are proposed at the same time. The reliability models of VSC converter, DC transformer and DC circuit breaker were established to analyze device and equipment level redundancy effects on DC distribution system reliability and difference between effects of function failure and insulation failure on DC distribution system reliability. Taking double side power supply DC distribution system for example, influencing factors are quantitatively analyzed and calculated. The equipment selection and redundant design of DC distribution system are proposed from the perspective of the reliability assessment.