The failure rates of underground distribution system components

The authors provide estimates of the failure rates of underground distribution system components. The estimates are based on information collected from a number of utility sources throughout the United States of America. They represent considerable field experiences of these sources over time spans on the order of 10 years. These data have been analyzed to produce comprehensive estimates of failure rates of underground components. The component failure rate estimates presented may be used by distribution engineers in assessing the reliability of distribution feeders. Computer programs have been developed which utilize these failure rates to predict reliability indices (for example, feeder average interruption frequency index and feeder average interruption duration index) for utility feeders