Development of distribution system reliability and risk analysis models

Background material needed to determine the state-of-the-art in reliability assessment techniques used by the distribution sector of the electric power utility industry is presented. Two distinct reliability assessment methods were identified, namely historical assessment and predictive assessment. The former method typically encompasses outage reporting and analysis schemes which predominate in the industry whereas the latter technique is mainly confined to the academic arena. The organization structure within a utility and the perceived need by each function for reliability data were identified. This task was invaluable to the design of an efficient information system such as required for historical reliability assessment. A detailed literature search of predictive or probabilitistic methods revealed a wealth of well accepted theory quite sufficient on which to base a predictive assessment model for radial distribution systems. This theory is summarized with a relevant data requirements. The present use and techniques accepted within the distribution sector of the utility industry was confirmed by a survey based on the response of 56 diverse utilities.