5.55
Date Code 20171021
Instruction Manual
SEL-421 Relay
Protection Functions
Out-of-Step Logic (Conventional)
Figure 5.35
OOS Logic Diagram
S
R
Q
O
SBD
R
eset
0
OS
TD
0
0
1/
8
CY
C
2 SE
C
0
UBO
SB
X7ABC
EOO
ST := N
EOO
ST := I
X6ABC
Set
tings
Set
tings
O
SBL
TCH := Y
Set
ting
R
ela
y
Wo
rd
Bits
R
ela
y
Wo
rd
Bits
R
ela
y
Wo
rd
Bit
R
ela
y
Wo
rd
Bit
EOO
ST := 0
OO
SB1 := Y
OO
SB2 := Y
OO
SB3 := Y
OO
SB4 := Y
OO
SB5 := Y
Set
ting
OS
B
OS
TI
OS
T
OS
T0
O
SB1
OO
SDET
O
SB2
O
SB3
O
SB4
O
SB5
R
eset T
ak
es
Priorit
y
OO
S Det
ect
ed A
ft
er
0
1 SE
C
Summary of Contents for SEL-421-4
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