IEEE 859-1987

1. Purpose
2. Scope
3. Equipment Classifications
3.1 Component
3.1.1 Termination
3.1.2 Line Section
3.2 Subcomponent
3.2.1 Line Segment
3.3 Unit
3.4 Terminal
4. Component and Unit States and Events
4.1 State
4.1.1 In-Service State
4.1.2 Outage State
4.2 Changes in State
4.2.1 Outage Occurrence
4.2.2 Outage Event
4.3 Outage Initiation
4.3.1 Automatic Outage
4.3.2 Manual Outage
4.4 Outage Type
4.4.1 Forced Outage
4.4.2 Scheduled Outage
4.5 Failure
4.5.1 Failure of Continuously Required Function
4.5.2 Failure of Response Function
5. State Times
5.1 Service Time
5.2 Outage Time
5.3 Reporting Period Time
5.4 Outage Duration
6. Exposure Parameters
6.1 Exposure (Time)
6.2 Exposure (Operations)
6.3 Weather
6.3.1 Adverse Weather
6.3.2 Major Storm Disaster
6.3.3 Normal Weather
7. Outage Indices
7.1 Rate Indices
7.1.1 Outage Rate
7.1.2 Failure Rate
7.1.3 Protective System False Operation Rate
7.2 Duration Indices
7.2.1 Mean Time to Outage
7.2.2 Mean Outage Duration
7.3 State Probability Indices
7.3.1 Availability
7.3.2 Unavailability
7.4 Probability of Failure Indices
7.4.1 Probability of Failure to Open on Command
7.4.2 Probability of Failure to Close on Command
7.4.3 Probability of Failure to Operate on Command
7.4.4 False Operation Probability

Describes terminology for analyzing and reporting outage occurrences of transmission facilities. Outage definitions and indices are given for units and components. Units are functional facilities which transfer power between designated points, components are specific pieces of equipment.