The Customer Average Interruption Duration Index (CAIDI) is a

reliability index Reliability index is an attempt to quantitatively assess the reliability of a system using a single numerical value. The set of reliability indices varies depending on the field of engineering, multiple different indices may be used to characterize ...

commonly used by

electric power Electric power is the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Standard prefixes apply to watts as with other SI units: thousands, millions and billions o ...

utilities A public utility company (usually just utility) is an organization that maintains the infrastructure for a public service (often also providing a service using that infrastructure). Public utilities are subject to forms of public control and r ...

. It is related to

SAIDI A Ṣa‘īdī (, Coptic: ⲣⲉⲙⲣⲏⲥ ''Remris'') is a person from Upper Egypt (, Coptic: ⲙⲁⲣⲏⲥ ''Maris''). Etymology The word literally means "from Ṣa‘īd" (i.e. Upper Egypt), and can also refer to a form of music or ...

and

SAIFI The Muslim Saifi, or sometimes pronounced Barhai are Muslim community, found in North India. They are also known as Saifi which denotes the Muslim sub-caste of blacksmiths and carpenters. A small number are also found in the Terai region of Nepa ...

, and is calculated as

\mbox = \frac

where

\lambda_i

is the failure rate,

N_i

is the number of customers, and

U_i

is the annual outage time for location

i

. In other words,

\mbox = \frac = \frac

CAIDI gives the average outage duration that any given customer would experience. CAIDI can also be viewed as the average restoration time. CAIDI 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 1.36 hours.

References

{{DEFAULTSORT:Caidi Electric power Reliability indices