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If the original breaker fails, retrip has no effect and the CBF continues operating and the TBTC
finally picks up. A trip command CBF TRIP is given to the adjacent breakers and the BFP is
completed.
[BTC]
+
"ON"
112, 1804
A
113, 1805
B
CBF
114, 1806
C
1644
CBF INIT-A
≥1
1645
CBF INIT-B
≥1
1646
CBF INIT-C
≥1
[RTC]
1647
CBF INIT
+
[APPL-CT]
+
"3P"
1
1570
CBF BLOCK
Figure 2.1.58
Fault
Adjacent
breakers
Closed
TRIP
Original
breakers
Closed
OCBF
TRTC
CBF
RETRIP
TBTC
CBF
TRIP
&
&
&
&
&
&
&
&
&
"OC"
"DIR"
&
Breaker Failure Protection Scheme Logic
Start CBFP
Normal trip
Open
Tcb
Toc
TRTC
TBTC
Figure 2.1.59
⎯
⎯
66
TBTC
0
t
t
0
0
t
0.00 - 300.00s
TRTC
0
t
≥1
0
t
≥1
0
t
≥1
0.00 - 300.00s
Retrip
Open
Tcb
Toc
Sequence Diagram
6 F 2 S 0 8 4 2
454
≥ 1
CBF TRIP
455
CBF TRIP-A
456
CBF TRIP-B
457
CBF TRIP-C
450
≥ 1
CBF RETRIP
451
CBF RETRIP-A
452
CBF RETRIP-B
453
CBF RETRIP-C
Trip
Open
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