5.27
Date Code 20171021
Instruction Manual
SEL-421 Relay
Protection Functions
Pole-Open Logic
Figure 5.17
Pole-Open Logic Diagram
LOPHA
(R
ela
y W
or
d Bit
)
52AA1
52AA2
SPO
A
SPOB
SPOC
0
3POD
0
SPOD
SPO
3PO
RESET
+
VA
(S
et
ting) 2
7PO
27APO
(R
ela
y W
or
d Bit
)
(S
et
ting) EPO := V
SPO
A
Rela
y
Wo
rd
Bits
SPOB
SPOC
NUMBK = 2
BK2TYP = 1
BK1TYP = 1
(S
et
ting) EPO := 5
2
Identical L
ogic f
or
B- and C
- Phases
Rela
y
Wo
rd
Bits
(C
ontr
ol
Inputs
)
—
Summary of Contents for SEL-421-4
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