EVALUATION OF DISTRIBUTION CIRCUIT RELIABILITY

A large percentage of individual customer interruptions originate within the actual distribution network serving these customers. It appears obvious, therefore, that this should be a fruitful area for detailed reliability evaluation and investigation. It appears, however, that detailed quantitative evaluation in this area is not practised by many utilities. Protective equipment is located in a network to protect equipment and to isolate equipment failures and faults. The type of protective equipment used can have a direct bearing on the frequency and duration of outages experienced by the customer. This paper illustrates that the inclusion of fault recognition and isolating characteristics of protective equipment in reliability calculations can have a significant effect on the reliability indices. The approach presented in this paper can be used in manual calculations or included in a digital computer program. It will, however, permit the distribution engineer to quantitatively evaluate the effect of proposed protection coordination schemes on the customer reliability levels and assist in the development of the most suitable configuration. Copyright © 1979 by the Institute of Electrical and Electronics Engineers, Inc.