IEVref: 692-08-04 ID: Language: en Status: Standard Term: service unavailability per customer interrupted Synonym1: Synonym2: Synonym3: Symbol: UCI Definition: sum of durations of all supply interruptions to individual customers during a time interval, divided by the product of the number of customers affected and the duration of that time intervalNote 1 to entry: If tij is the duration of the ith interruption of supply to customer j during a time interval of duration T, and NNS the number of customers affected, then the service unavailability per customer interrupted is given by${U}_{\text{CI}}=\frac{{\sum }_{i}{\sum }_{j}{t}_{ij}}{{N}_{\text{NS}}T}$ Note 2 to entry: 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: Service unavailability per customer interrupted can be used to describe past performance or to estimate expected future performance. Note 5 to entry: This entry was numbered 191-27-04 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: