ASUI

The Average Service Unavailability Index (ASUI) is a reliability index commonly used by electric power utilities. It is calculated as

ASUI = ∑ U i N i ∑ N i × 8760 = 1 − ASAI

where N i is the number of customers and U i is the annual outage time (in hours) for location i . ASUI can be represented in relation to SAIDI (where annual SAIDI is given in hours) as

ASUI = SAIDI 8760