r_20261029_184130_eece

done

drawing: Sample4.png
reference: none
at: 2026-10-29T18:41:30Z

Review

If these are right, every cut set is right: the cut sets are computed from the paths and what can fail.

1 · Power reaches the load by these paths

Click a path to light it up on the drawing. Is every part on that route boxed, and nothing extra?

Path 1 7 parts: B71 → CB7-1 → CBRX → B7RX → Three Phase Rx → BNRX → Neutral Rx Path 2 7 parts: B72 → CB7-2 → CBRX → B7RX → Three Phase Rx → BNRX → Neutral Rx No route is missing: every way power can flow on the drawing lights up in some path.

2 · Parts not on the drawing

1 added: GRID. Each one belongs (see Not on the drawing).

3 · Assumptions

Can fail: breaker, busbar, other Success: the supply is OK if at least 1 of the 2 paths works Boundary: Source: a virtual 765 kV system feeding Bus 1 and Bus 2. Sink: the neutral reactor ground. Not modelled: Spare Phase Rx and Spare Neutral Rx; Protection relays, CTs, CCVT, cooling/gas devices (63, 71G, 49, 71Q); Remote-end line supply

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Summary

Single points of failure

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

{B7RX}
{BNRX}
{CBRX}
{Neutral Rx}
{Three Phase Rx}

Pairs

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

{B71, B72}
{B71, CB7-2}
{B72, CB7-1}
{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

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Page 1

Not on the drawing

node	type	connected to	why
`GRID`	source	B71, B72	Virtual common source feeding 765 kV Bus 1 and Bus 2 so that one source covers both bus feeds

Block diagram

Series runs left to right; parallel branches stack.

Run r_20261029_184130_eece · from Sample4.png · 9 blocks · 5 single points 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

B71→CB7-1

B72→CB7-2

→CBRX→B7RX→Three Phase Rx→BNRX→Neutral Rx

Cut sets

Reference: none

No verdict: nothing was compared with a reference. These are the model's own cut sets.

This model

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

Order 1 (5)

{B7RX}
{BNRX}
{CBRX}
{Neutral Rx}
{Three Phase Rx}

Order 2 (4)

{B71, B72}
{B71, CB7-2}
{B72, CB7-1}
{CB7-1, CB7-2}

Gaps

Spare Phase Rx / Spare Neutral Rx Spares are drawn tied to B7RX/BNRX/ground in parallel with the in-service reactors, but a spare single-phase unit normally has to be switched in by hand to replace a failed phase. Its normal state and how it is switched in are not shown, so I left the spares out of the model rather than count them as instant redundancy.
Line (remote end) The 765 kV line could also energize the reactor from the remote terminal. The drawing does not show the remote end, so the model supplies the reactor only from local Bus 1 and Bus 2.

Assumptions

Scope: The 765 kV shunt reactor branch: the bus supply through CB7-1/CB7-2 to the line tap, then CBRX, B7RX, the three-phase reactor, BNRX and the neutral reactor to ground.. The drawing is a reactor protection SLD, so the useful reliability question is whether the reactor is available.

Boundary: Source: a virtual 765 kV system feeding Bus 1 and Bus 2. Sink: the neutral reactor ground.. The two buses are the local supply edges of the drawing, and the reactor branch ends at the ground connection.

Can fail: breaker, busbar, other. Breakers, buses and the reactor units (typed other) are the primary equipment that can fail. The virtual source and the ground sink are treated as perfect. The Line node is only the tap junction, so it is a perfect connector. CTs, VTs and relays are left out because they belong to the protection secondary, not the power path.

Success: any_path. The shunt reactor is in service when at least one energized path runs from a 765 kV bus through the breakers, the reactor and the neutral reactor to ground.

Not modelled:

Spare Phase Rx and Spare Neutral Rx: These are standby units that need manual reconnection, so they give no automatic redundancy (flagged).
Protection relays, CTs, CCVT, cooling/gas devices (63, 71G, 49, 71Q): These are secondary/protection systems. Including them would mean modelling trip and spurious-trip logic.
Remote-end line supply: It is not shown on the drawing (flagged).