Distribution System Reliability Assessment Based On Boolean Logic Driven Markov Processes

Distribution system reliability is a kind of measurement to the quality of electricity in term of meeting the need of electricity customers. In power system distribution system connect directly to customers. It includes distribution transformers, high voltage and low voltage distribution lines, various distribution equipments. Nowadays as the society system reforms and power market establishes, power enterprises have to change their ideas and pay more attention to how to increase the power reliability to meet customers require. So the time that only focus on power generation and ignore power- supply reliability of distribution systems has past. As the demand for reliability of distribution systems is higher and higher, and according to Stat.80 percent of the unavailability of supply to a customer are caused by the faults of distribution system, the modern power enterprises have set a new guidelines that is do their best to analysis and research the reliability of distribution system, at the same time evaluate it correctly too. In a word, researches into distribution system reliability and evaluation methods become more and more important not only on theoretical exploration but also on reality world.Firstly, the significant meaning of distribution system reliability and its developing state and trend are presented in this paper. Moreover analysis of basic theories and methods, especially some commonly used methods such as analytical method, interval analysis method, Monte- Carlo simulation method, fault-traverse technique method, EUP method are given in this paper too.Secondly, a new method in term of distribution system reliability research named Markov Processes based on Boolean Logic Driven (abbr. BDMP) is studied in this paper. It combines Boolean algebra and Markov Processes. The mathematics model and basic algorithm of fault trees are applied in this new method. So it (BDMP) can be simplified as a kind of fault tree to some extent.Thirdly, a fault tree is established according to distribution system configuration. Boolean algebra is applied to simplify logics among so many components. Then relationships between top event and each basic failure are available and the probability of this distribution system reliability can be calculated. So we can evaluate this distribution system reliability effectively, of course we need to know the probability of each basic component's reliability at first.Fourthly, through analyzing a practical example, BDMP is proved to be feasible and really work very well.