Lightning and reliability-a comparison of three utilities

Abstract

Lightning can have varying effects on distribution system reliability. It has been thought that as the lightning density increases so do the outages due to lightning. In areas with high lightning density, distribution reliability can be highly dependant on lightning while that dependency is reduced as the lightning density decreases. Lightning has been identified as one of the leading causes of outages on distribution systems, according to an IEEE study. This study looks at three utility systems distribution reliability and how lightning activity affects it. The three different systems have varying levels of lightning density. Florida Power incurs some of the highest lightning density in the United States. Detroit Edison, while not having the lowest lightning density, is in a lower lightning density area and incurs roughly 20% the lightning density of Florida Power. Carolina Power and Light has a lightning density between that of Detroit Edison and Florida Power. The purpose of this study was to see if there is any correlation between lightning activity and distribution system reliability, and to develop a method to normalize reliability data to remove the variability of weather as a factor in determining reliability trends.