A Reliability Level Tree Algorithm for Reliability Evaluation of Medium Voltage Distribution Networks

A reliability evaluation algorithm for medium voltage distribution networks is proposed.Considering such processes as fault isolation,fault restoration and power source switching-over in medium voltage distribution networks as well as the action characteristics of switching-device(SD),the concepts of reliability level tree for SD and circuit breaker as well as the algorithm to form the two kinds of trees are presented,and then using the proposed forming techniques a medium voltage distribution network can be equivalent to a SD tree and circuit breaker tree.A dynamic linked list is adopted to store the information of reliability level trees to reduce redundancy storage and storage complexity.Taking the influences of equipment failures and standby switching-over on reliability of load point and so on into account,based on reliability level a unified model to calculate reliability indices of load points is given.In view of the fact that the reliability level trees possess the features of simplified distribution network and during the calculation only seek up mode is utilized,the proposed algorithm is efficient.Applying the proposed algorithm,the reliability of RBTS system and a 10 kV distribution network in a certain region are evaluated.Analysis results show that the proposed algorithm can be used for reliability evaluation of traditional medium voltage distribution network and the reliability evaluation of medium voltage distribution network after new energy is connected to it.