IEVref: 692-08-01 ID: Language: en Status: Standard Term: interruption frequency per customer served Synonym1: system average interruption frequency index, CA US [Preferred] Synonym2: SAIFI [Admitted] Synonym3: Symbol: fCS Definition: number of interruptions of supply to individual customers during a given time interval, divided by the product of the total number of customers and the duration of that time intervalNote 1 to entry: If the power supply to customer j is interrupted nj times during a time interval of duration T, and the total number of customers served is NS, then interruption frequency per customer served is given by ${f}_{\text{CS}}=\frac{{\sum }_{j}{n}_{j}}{{N}_{\text{S}}T}$ 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 served can be used to describe past performance or to estimate expected future performance. Note 5 to entry: This entry was numbered 191-27-01 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: