Distribution System Reliability Evaluation Algorithm

With the development of urban economy and the improvement in life quality of the people, the requirement to the electric energy quality of user has been more and more rigorous. Distribution system is required to be layout scientifically and rationally. Especially with the issuance and implementation of the electric power law of P. R. C and the initiation of professed service of power industry, the reliability of distribution system plays an increasingly important part in power production and management. The distribution system has a direct connection to customers, so distribution system can make most influence on customers. The statistics show that more than 80% letting off of customers is leaded by distribution system fault. So the evaluation of distribution system reliability and improving system reliability is most significant.Base on the comprehensive reading of references about distribution system reliability, the paper compares several reliability evaluation methods and take the traditional method: network-equivalent approach, and expound it in detail .At the same time, based on the combination of interval operation with network-equivalent approach to reliability assessment of distribution system, an interval evaluation method of reliability of distribution system is presented. The paper chooses main feeder F4 among RBTS Bus6 and its three branch feeder F5 F6 and F7 as studying system, and using the evaluation, this paper compare these two methods , the effectiveness of the interval evaluation method had been proved . At the same time, base on the foundation of result, the paper analyses the essential factors influencing the reliability and putsforward effective measure for the transformation of electric power system.Interval evaluation method takes into account the uncertainty of all of the parameters and is able to provide strict bounds of indices ,with only one evaluation .The final interval will contain all possible solutions due to the variations of the input parameters . It is also shown that it is possible to solve the dependence of interval algorithm and perform practical engineering reliability analysis by using interval evaluation with some improved and simplifying measures.