IEEE 859-2018

This standard defines terminology and indices for reporting and analyzing outage occurrences of transmission facilities. Outage definitions and indices are given for two general types of facilities: units and components. Units are functional facilities that transfer power between designated points, while components are specific pieces of equipment. Outage definitions are given both for describing the outage history of a particular facility and for describing groups of individual outage occurrences that are related in some way.