SUSTAINED OUTAGE INDICES

Average Service Availability Index ASAI is a measure of the average availability of the sub transmission and distribution systems to serve customers. It is the ratio of the total customer minutes that service was available to the total customer minutes demanded in a time period. It is normally expressed as a percentage.

Customer Average Interruption Duration Index (CAIDI) – Represents the average time to restore service per interrupted customer (minutes/interruption)

CAIDI=Sum of customer interruption durations   = 71.01 Min.

System Average Interruption Duration Index (SAIDI) – Represents the average time each customer is interrupted (minutes/year)

SAIDI= Sum of customer interruption durations  = 18.31 Min.

System Average Interruption Frequency Index (SAIFI) - Represents the average number of interruptions per customer.  (interruptions/year)

                                    SAIFI=Sum of Customer Interruptions      =  .285

Momentary Average Interruption Frequency Index (MAIFI) – Represents the average number of momentary (two minutes or less) interruptions per customer. 

                                    MAIFI=Sum of Momentary Customer Interruptions      =  2.885

Average System Availability Index (ASAI) – Represents ratio of time the system provided service to each customer.

                        ASAI=Total hours service was available

                        Total hours service was demanded

 Past Years ASAI Ratio