Schweitzer Engineering Laboratories SEL-421-4 - Figure 5.114 Circuit Breaker Failure Seal-In Logic Diagram

5.156
SEL-421 Relay Instruction Manual Date Code 20171021
Protection Functions
Circuit Breaker Failure Protection
50FOC1 C-Phase flashover current threshold
BFTRIP1 Breaker 1 circuit breaker failure trip
a
For Circuit Breaker 2, replace 1 with 2 in the setting label.
Figure 5.114 Circuit Breaker Failure Seal-In Logic Diagram
Table 5.80 Circuit Breaker Failure Relay Word Bits (Sheet 2 of 2)
Name
a
Description
IABKn
BFI3Pn
BnOPHA
50FAn
50FBn
50FCn
IBBKn
BnOPHB
ICBKn
50FPn
BnOPHC
BFI3PTn
Relay
Word
Bit
Relay
Word
Bit
BFIATn
Relay
Word
Bit
Relay
Word
Bits
Relay
Word
Bits
SELOGIC
Setting
0
BFIDOn
BFISPn
0
—
+
—
+
—
+
BFIAn
50FAn
SELOGIC
Setting
0
BFIDOn
BFISPn
0
BFI3Pn = BFI3PTn OR . . .
When the Scheme requires
BFI Seal-In.
BFIAn = BFIATn OR ...
When the Scheme requires BFI Seal-In.
Common Logic for
Schemes 1 and 2.
n = 1 or 2; corresponds to
Circuit Breaker 1 or
Circuit Breaker 2