Reliability analysis of distribution networks

Historical assessment and predictive methods are normally used to evaluate the reliability of a distribution network. Most utilities focus more on historical assessment rather than predictive methods. Predictive methods are categorised into analytical and simulation methods. The difference between these methods is the way in which the system reliability indices are evaluated. In this paper, the authors apply both analytical and simulation methods to calculate the reliability indices such as System Average Interruption Frequency Index (SAIFI) and System Average Interruption Duration Index (SAIDI) for two distribution systems. The Test systems are bus six of the Roy Billinton Test System and a real distribution network in Western Cape, South Africa. Results from these two approaches and some changes in operating philosophy are presented and compared in the paper. Probability distribution of SAIFI and SAIDI which give information about the variability of the indices and are therefore useful for decision making were obtained.