SAIDI
The System Average Interruption Duration Index is commonly used as a reliability indicator by electric power utilities. SAIDI is the average outage duration for each customer served, and is calculated as:
where is the number of customers and is the annual outage time for location, and is the total number of customers served. In other words,
SAIDI is measured in units of time, often minutes or hours. It is usually measured over the course of a year, and according to IEEE Standard 1366-1998 the median value for North American utilities is approximately 1.50 hours.
