r_20261029_173926_9afa

done

drawing: drawing.png
reference: transformer-protection-v1
at: 2026-10-29T17:39:26Z

Summary

Single points of failure

1 component: if any one of these fails on its own, the supply is lost.

{XFMR}

Pairs

2 pairs: the supply is lost only if both components of a pair fail together.

{CB5-1, CB5-2}
{CB7-1, CB7-2}

Click a set to highlight its components on the drawing and in the block diagram; click it again to clear.

Drawing and graph

block (can fail)perfect connectorin a cut-set difference show all connections

Hover a box to see its own connections.

Page 1

Not on the drawing

node	type	connected to	why
`SRC-765`	source	B71, B72	Spec requires source connected to B71 and B72
`SINK-500`	sink	B51, B52	Spec requires sink connected to B51 and B52

Block diagram

Series runs left to right; parallel branches stack.

Run r_20261029_173926_9afa · from drawing.png · 5 blocks · 1 single point of failure. Drawn in BlockSim's RBD layout so it can be rebuilt there block for block; this is a picture, not a BlockSim file. The machine-readable export is the Open-PSA fault tree.

Nested view

CB7-1CB7-2

→XFMR→

CB5-1CB5-2

Cut sets

Against the reference: pass

No differences.

This model

Minimal cut sets up to order 3. Click an order to show or hide it.

Order 1 (1)

{XFMR}

Order 2 (2)

{CB5-1, CB5-2}
{CB7-1, CB7-2}

Gaps

None flagged.

Assumptions

Can fail: breaker, transformer. Spec: only the four breakers and the transformer can fail; CTs and buses are perfect connectors.

Success: any_path. Spec: any one source-to-sink path is enough.

Not modelled:

Protection relays, CT secondaries, BFI links, RTD, 34 kV tertiary: Out of scope per spec (primary power path only).
Bus and CT failures: Treated as perfect connectors per spec.
Operating errors: None in this study per spec.