Resilience Score

A relative 0–100 index for comparing how well each load is supplied. It is not an availability figure or a probability.

1. What this check does

For every load and every node marked critical, RokBench removes each other node in turn and checks whether the load is still energized, under failure conditions and under planned maintenance. It also counts how many independent supply paths reach the load. These results are combined into a relative score and a color band.

2. Inputs used

Nodes: type, status and critical flag.
Connections: direction of power flow (from → to), normally closed or normally open, and any breaker or cable they pass through.
Sources are utility, generator and battery nodes.

3. Formulas and assumptions

Energized reachable from any in-service source through in-service nodes and usable connections Failure normally closed connections + automatic transfers (normally open connections into an ATS or STS) Maintenance failure rules + planned switching (any normally open connection, such as a bus tie) Upstream elements nodes that lie on some supply path to the load Failure survival share of upstream single-element outages the load survives under failure rules Maintenance survival same, under maintenance rules Independent paths number of supply paths that share no node, from any source to the load Score weighted combination of the three, limited when a single point of failure exists

Relative resilience index. Not an availability figure. Scores compare arrangements; they do not predict outage frequency or duration.
Every node is treated as able to fail. Failure rates, repair times and component quality are not considered.
A load with any single point of failure cannot score in the green band.
Batteries count as sources, so loads behind a UPS survive upstream outages for the battery ride-through time only.
Color bands: green, yellow, orange and red from highest to lowest; gray means the load is not energized in the normal configuration. The weights and band limits are part of the engine and may be refined; changes are recorded in the Changelog.

4. What is NOT checked

Equipment ratings and capacity: a path that exists may not be able to carry the load (see Loading & Headroom, planned).
Transfer timing, ride-through duration and load sensitivity to interruptions.
Common-mode failures such as fire in a shared room, shared controls or a shared fuel system.
Protection coordination and fault propagation.

5. Reference standards

Pointers only; consult the edition adopted by your authority having jurisdiction.

IEEE Std 3006.7 — reliability of commercial and industrial power systems (background)
IEEE Std 493 (Gold Book) — reliability analysis methods (background)

6. Validation cases

Hand-calculated cases run on every change. See Validation.

7. Known issues and changes

See the Changelog. Try the tool: Workbench.