Abstract: In order to deal with the contradiction of limited station corridor and high load density of urban power grid,the development of AC/DC distribution network is an important development trend to solve the problem.However,the technology of key equipment such as medium voltage DC circuit breaker and DC transformer is not mature and the construction standard is not perfect,so it is necessary to evaluate and analyze the reliability level of equipment and distribution system.In this paper,by analyzing the factors that affect the reliability of AC/DC distribution network,the reliability evaluation model of key equipment in AC/DC distribution network was established and the reliability parameters were calculated.The reliability evaluation method of distribution system is based on the minimum cut set method.According to the evaluation results,compared with the traditional AC distribution network,the two-way connection characteristic of flexible AC and DC distribution network further improves the overall power supply reliability of the system on the basis of realizing the whole system’s flexible control.

Key words: AC/DC distribution network, reliability evaluation, flexible power electronic substation, minimum cut set