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4.23
Date Code 20080213
Instruction Manual
SEL-351A Relay
Loss-of-Potential, Load Encroachment, and Directional Element Logic
Directional Control for Neutral-Ground and Residual-Ground Overcurrent Elements (Not in SEL-351A-1)
q
w
and
.
Figure 4.11
Channel IN Current-Polarized Directional Element
Forward Threshold = (Channel I
N
Nominal Rating) • (Phase Channels Nominal Rating) • (0.05)
2
Forward Threshold:
Reverse Threshold = —(Channel I
N
Nominal Rating) • (Phase Channels Nominal Rating) • (0.05)
2
Reverse Threshold:
32IE is highest
w
R32I
(Reverse)
F32I
(Forward)
Best Choice
Ground
Directional
Logic
50GF
Enable
Forward
Threshold
32IE
Reverse
Threshold
50GR
q
Re[I
G
•I
N
*]
I
G
I
N
Relay
Word
Bits
Relay
Word
Bit
Relay
Word
Bit
Relay
Word
Bit
choice that is asserted
(I
G
= 3I
0
)
(Residual)
Summary of Contents for SEL-351A
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