A Fuse-Blow Scheme

A fuse-blow philosophy has been adopted by some utilities in an effort to decrease the number of momentary average interruption frequency index (MAIFI) seen by their customers. This practice has the inherent drawback that, by converting a temporary fault (e.g., lightning and animals) into a sustained interruption, they are in effect decreasing the reliability of their system [i.e., system average interruption duration index (SAIDI) will increase]. This article addresses the impact of a fuse-blow philosophy on long lines commonly found in rural electric utilities as well as shorter lines that are ubiquitous in more urban areas. It also assesses the differences in the impact of these schemes in terms of both power quality (momentaries) and reliability issues. Detailed analysis of the impact on the utility system is presented and discussed.