View source for CTAIDI

The '''Customer Total Average Interruption Duration Index''' ('''CTAIDI''')<ref>{{cite book
|url =https://books.google.com/books?id=9EShPwTRnoUC
|title = Power Distribution Planning Reference Book, Second Edition
|first = H. Lee
|last = Willis
|date = March 2004
|isbn = 9781420030310
|accessdate = 22 July 2015
}}</ref> is a [[reliability index]] associated with [[electric power distribution]].{{cn|date=January 2021}}  CTAIDI is the average total duration of interruption ''for customers who had at least one interruption during the period of analysis'', and is calculated as:

<math>
\mbox{CTAIDI} = \frac{\sum{U_i N_i}}{N_{io}}
</math>

where <math>N_i</math> is the number of customers and <math>U_i</math> is the annual outage time for location <math>i</math>, and <math>N_{io}</math> is the number of customers at location <math>i</math> that were interrupted. In other words,

<math>
\mbox{CTAIDI} = \frac{\mbox{sum of durations of customer interruptions}}{\mbox{number of distinct customers interrupted}}
</math>

CTAIDI is measured in units of time, such as minutes or hours.  It is similar to [[CAIDI]], but CAIDI divides the total duration of interruptions by the number of interruptions whereas CTAIDI divides by the number of interrupted customers.  When CTAIDI is much greater than [[CAIDI]], the service outages are more concentrated among certain customers.

CTAIDI also has the same numerator as [[SAIDI]], but SAIDI divides the total duration of interruptions by the total number of customers served.  The fraction of distinct customers interrupted illustrates the relationship between several reliability indicators:

<math>
 \frac{N_{io}}{N_i} = \frac{\mbox{SAIDI}}{\mbox{CTAIDI}} = \frac{\mbox{SAIFI}}{\mbox{CAIFI}}
</math>

==References==
{{Reflist}}

{{Reliability indices}}
[[Category:Electric power]]
[[Category:Reliability indices]]


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