Average Service Availability Index

The Average Service Availability Index (ASAI) is a reliability index commonly used by electric power utilities. ASAI is calculated as

[math]\displaystyle{ \mbox{ASAI} = \frac{\sum{N_i} \times 8760 - \sum{U_i N_i}}{\sum{N_i} \times 8760} }[/math]

where [math]\displaystyle{ N_i }[/math] is the number of customers and [math]\displaystyle{ U_i }[/math] is the annual outage time (in hours) for location [math]\displaystyle{ i }[/math]. ASAI can be represented in relation to SAIDI (when the annual SAIDI is given in hours)

[math]\displaystyle{ \mbox{ASAI} = 1 - \frac{\mbox{SAIDI} }{8760} }[/math]

See also

• ASAI
• ASIDI
• ASIFI
• ASUI
• CAIDI
• CAIFI
• CTAIDI
• MAIFI
• SAIDI
• SAIFI