Reliability & N-1 Contingency Analysis

Evaluate load service continuity with traceable MTBF/MTTR inputs, minimal N-1/N-2 cut sets, and load-weighted outage metrics.

Method & Assumptions

Component availability is computed from Mean Time Between Failures (MTBF) and Mean Time To Repair (MTTR) values per IEEE Std 493 (Gold Book) and IEEE Std 1366:

A = MTBF / (MTBF + MTTR)

Expected outage hours per year per component:

downtime = (8760 / MTBF) × MTTR

System unavailability is computed using minimal cut sets up to N-2 failure combinations. Load List records are matched to One-Line service points to calculate expected energy not served (EENS), load-weighted service interruption hours, and interruption frequency. Components are loaded from the active One-Line Diagram.

Connector elements (cables, feeders, links) define topology but are excluded from the reliability component count and are not assigned standalone failure probabilities.

References: IEEE Std 493-2007, IEEE Std 1366-2012, IEC 60300-3-2.

Component Override Values

Leave MTBF/MTTR blank to use values stored on the One-Line component. Overrides and their source evidence are saved as governed project inputs.

Click Load from One-Line to populate component list.