reliability index

In thepower supply industry, there are various indices that are used to index the supply quality of the electric power supply system and the supply reliability of the consumer. These indices are concerned with how often and for how long the electricity customer has power interruptions, i.e. they are concerned with the outage duration and outage frequency.

The IEEE has defined generally accepted utility reliability indices in Standard P1366, the "Guide for Electric Distribution Reliability Indices." The indices included are instantaneous interruption, the event that led to the instantaneous interruption, and continuous interruption. The following indices have been defined to determine these criteria:

• System Average Interruption Duration Index( SAIDI) is the average system interruption duration,
• System Average Interruption Frequency Index ( SAIFI) is the average system interruption frequency,
• Customer Average Interruption Duration Index( CAIDI) is the average consumer interruption duration,
• Customer Average Interruption Frequency Index( CAIFI) is the average consumer interruption frequency, and
• Momentary Average Interruption Frequency Index( MAIFI) is the momentary average interruption frequency.