Schweitzer Engineering Laboratories SEL-421-4 - Figure 5.117 Circuit Breaker Failure Trip Logic Diagram; Figure 5.116 Flashover Protection Logic Diagram; Figure 5.115 Failure to Interrupt Load Current Logic Diagram

5.157
Date Code 20171021 Instruction Manual SEL-421 Relay
Protection Functions
Circuit Breaker Failure Protection
Figure 5.115 Failure to Interrupt Load Current Logic Diagram
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
Figure 5.116 Flashover Protection Logic Diagram
EFOBFn := Y
50FOAn
52AAn
BLKFOAn
Relay Word bit BLKFOAn asserts if an A-phase
single-pole trip occurs, or if the corresponding
circuit breaker closes.
n = 1 or 2; corresponds to
Circuit Breaker 1 or
Circuit Breaker 2
BnOPHA
50FOn
IABKn
FOBFn
FOAn
FOBn
FOCn
Relay
Word
Bit
Relay
Word
Bit
Relay
Word
Bits
Relay
Word
Bits
5 CYC
0
FOPUn
0
6 CYC
0
SELOGIC
Settings
S
R
Q
—
+
Setting
Figure 5.117 Circuit Breaker Failure Trip Logic Diagram
BFTRIPn
Relay
Word
Bit
TDURTn
Relay
Word
Bit
TRGTR
Relay
Word
Bit
SEL OGIC
Settings
TDUR3D
0
TAR R
Serial Port
Command
Target Reset
Front Panel
BFULTRn
BFTRn
RSTTRGT