Sel SEL-421 - Circuit Breaker Failure Seal-In Logic Diagram; Failure to Interrupt Load Current Logic Diagram

R.1.124
SEL-421 Relay Reference Manual Date Code 20111215
Protection Functions
Circuit Breaker Failure Protection
Figure 1.78 Circuit Breaker Failure Seal-In Logic Diagram
Figure 1.79 Failure to Interrupt Load Current Logic Diagram
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
IABKn
ELCBFn := Y
BnOPHA
50LCAn
50LCBn
50LCCn
IBBKn
BnOPHB
ICBKn
50LPn
BnOPHC
BFILCn
LCBFn
Relay
Word
Bits
SELOGIC
Setting
Relay
Word
Bits
Relay
Word
Bit
LCPUn
0
—
+
—
+
—
+
Setting
n = 1 or 2; corresponds to
Circuit Breaker 1 or
Circuit Breaker 2