Considerations of relevant factors in setting distribution system reliability standards

The development of distribution reliability standard metric values, e.g., system average interruption frequency index (SAIFI), system average interruption duration index (SAIDI), customer average interruption duration index (CAIDI), etc., against which all utilities can compare themselves is impossible. There are too many differences between data collection processes and utility systems characteristics to make development of universally applicable standard metric values and comparisons against such standard metric values valid. Rather, the development of uniform standard metric values, which utilities compare themselves to their own historical performance is more practical. If cross comparisons between utilities are desirable, a number of issues and factors associated with individual utilities must be taken into considerations in establishing distribution reliability standards. The paper identifies a number of such important and pertinent factors and issues in setting distribution reliability standards, and illustrates the issues and factors using historical reliability performance data from a number of Canadian utilities.