Using AST and FLISR to Improve System Reliability
Fortunately, as challenges mount for reliability and efficiency for electric utilities, technologies, including new ones and existing ones that continue to improve, help keep pace with these challenges. Two of these technologies are AST (Automatic Source Transfer) and FLISR (Fault Location, Isolation, and Service Restoration) to which utilities should pay attention in particular.
The reliability of an electric power utility is most commonly measured by SAIDI (System Average Interruption Duration Index), which is the average outage duration for each customer served and is calculated from the sum of all customer interruption durations per the total number of customers served. Studies have shown that a 20-37% reduction in outage duration can lead to a 7-15% improvement to SAIDI. The most effective way to improve SAIDI is to reduce the consumer outage duration and system automation has proven to be an efficient tool for improving system reliability.