SAIFI

From Wikipedia, the free encyclopedia

The System Average Interruption Frequency Index is commonly used as a reliability indicator by electric power utilities. SAIFI is the average number of interruptions that a customer would experience, and is calculated as

$\mbox{SAIFI} = \frac{\mbox{total number of customer interruptions}}{\mbox{total number of customers served}}$

SAIFI is measured in units of interruptions per customer. 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 1.10 interruptions per customer.