Collecting and Categorizing Information Related to Electric Power Distribution Interruption Events: Data Consistency and Categorization for

Reliability of electric power systems remains an im- portant societal issue. While transmission disturbances draw na- tional attention and scrutiny, service interruptions at the distribu- tion level are the primary concern of the end-use customer and their regulatory and governmental representatives. Much effort has been expended in developing methods to uniformly and con- sistently quantify the reliability of distribution service based on electric system performance. However, the results of a nationwide survey of recorded information used for calculating distribution reliability indices performed in 1998 by the Working Group on System Design indicate that significant inconsistencies exist in the data, categorization of that data, and in the collection processes used within the industry. This paper is one in a series of papers that discuss the collection and categorization of information related to electric power distribution interruption events and will be used in the development of industry guidelines. This paper presents a min- imal set of data and a consistent categorization structure that when used in combination with IEEE Std. 1366 will promote consistency in how the industry collects data for the purpose of benchmarking distribution system performance.