IEVref: 692-08-02 ID: Language: en Status: Standard Term: interruption frequency per customer interrupted Synonym1: customer average interruption frequency index, CA US [Preferred] Synonym2: CAIFI [Admitted] Synonym3: Symbol: fCI Definition: number of supply interruptions experienced by the individual customers affected at least once during a time interval, divided by the product of the number of affected customers and the duration of that time intervalNote 1 to entry: If NNS is the number of customers affected and the supply of customer j is interrupted nj times during a time interval of duration T, then the interruption frequency per customer interrupted is given by${f}_{\text{CI}}=\frac{{\sum }_{j}{n}_{j}}{{N}_{\text{NS}}T}$ When determining NNS, each customer affected must be counted only once, regardless of the number of interruptions experienced during that time interval. Note 2 to entry: Usually, only sustained interruptions are considered. Note 3 to entry: The term "customer" represents the end user and not some intermediate distribution system or company. Note 4 to entry: Interruption frequency per customer interrupted can be used to describe past performance or to estimate expected future performance. Note 5 to entry: This entry was numbered 191-27-02 in IEC 60050-191:1990. Publication date: 2017-12-15 Source: Replaces: Internal notes: CO remarks: TC/SC remarks: VT remarks: Domain1: Domain2: Domain3: Domain4: Domain5: