IEEE 859:2019

Scope
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.
Purpose
This standard is intended to aid the electric power industry in reporting and analyzing outage occurrences of transmission facilities. Use of systematic, precise definitions is essential for meaningful exchange of data. It is expected that specific instructions for reporting outages will be developed by the industry based on these definitions. The outage definitions and indices are intended for use in system planning models, operations and maintenance planning, and system design. The definitions and indices may not be sufficiently detailed to cover the information required for equipment design.
Abstract
Revision Standard - Active. Terminology and indices for reporting and analyzing outage occurrences of transmission facilities are defined in this standard. 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.