Methods: Reliability indices
reliability.outage-log.indices · Version 0.1.0
Method
Interruptions per customer = customers interrupted ÷ customers served. Minutes per customer = customer minutes ÷ customers served. Minutes per interrupted customer = customer minutes ÷ customers interrupted. Availability = 1 − minutes per customer ÷ minutes in the period.
Assumptions
- An interruption longer than the threshold is sustained; one of the threshold or less is momentary and left out of these indices.
- Customers served is the figure you enter, not an average we compute.
Sources
- Form EIA-861, Annual Electric Power Industry Report, instructions, OMB 1905-0129, Schedule 3 Part B: the two indices the form collects; a sustained interruption is one of more than 5 minutes; see docs/derivations/reliability.md
- IEEE PES Boston chapter tutorial, John Teixeira, National Grid, February 19, 2019, Slides 75 to 90: the indices the federal form does not collect, and the major-event-day threshold
Worked examples
| Example | Independent source | Tolerance | Last result |
|---|---|---|---|
| A year against 12,000 customers served | reliability/index-calculator spec, scenario "Annual indices": 18,000 customer interruptions and 2,400,000 customer minutes | ±0.005, ±0.05, ±0.005, ±0.00005 | Not yet run in CI |
| A log holding one brief interruption | Own example: the 4-minute interruption is momentary and left out of the sustained indices | ±0, ±0.005 | Not yet run in CI |
Known differences from reference engines
None recorded.
Cite this tool
Reliability indices, version 0.1.0. gridprims. https://gridprims.com/tools/reliability/outage-log/indices/