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Application – 2
2–25
50/50N Instantaneous Overcurrent, Phase and
Neutral Circuits
The Instantaneous Phase (50) and Instantaneous
Neutral (50N) overcurrent functions provide fast
tripping for high fault currents. The settings of both
functions must be set such that they will not pickup
for fault or conditions outside the immediate
protective zone. If the neutral current input is
connected to step-up transformer’s neutral CT, the
50N function can be used as a breaker flashover
protection when used in conjunction with external
breaker failure protection. Ranges and Increments
are presented in Table 2-9.
N
O
I
T
C
N
U
F
E
G
N
A
R
T
N
I
O
P
T
E
S
T
N
E
M
E
R
C
N
I
)
0
5
(
t
n
e
r
r
u
c
r
e
v
O
s
u
o
e
n
a
t
n
a
t
s
n
I
p
u
k
c
i
P
A
0
.
0
4
2
o
t
1
.
0
)
A
0
.
8
4
o
t
1
.
0
(
A
1
.
0
e
s
n
o
p
s
e
R
e
m
i
T
p
i
r
T
s
e
l
c
y
C
2
<
–
)
N
0
5
(
l
a
r
t
u
e
N
,
t
n
e
r
r
u
c
r
e
v
O
s
u
o
e
n
a
t
n
a
t
s
n
I
p
u
k
c
i
P
A
0
.
0
4
2
o
t
1
.
0
)
A
0
.
8
4
o
t
1
.
0
(
A
1
.
0
e
s
n
o
p
s
e
R
e
m
i
T
p
i
r
T
s
e
l
c
y
C
2
<
—
Table 2-9
Instantaneous Overcurrent (50/50N) Setpoint Ranges
The relay current (I
R
) is equal to the primary current (I
p
) divided
by the appropriate CT ratio.
50 PICKUP
________ Amps
50N PICKUP
________ Amps
Summary of Contents for M-3425
Page 1: ...Instruction Book M 3425 Generator Protection ...
Page 14: ... 13 M 3425 Generator Protection Relay Figure 1 External Connections ...
Page 33: ...x M 3425 Instruction Book This Page Left Intentionally Blank ...
Page 89: ...M 3425 Instruction Book 2 52 This Page Left Intentionally Blank ...
Page 125: ...1 3 A B C M 3425 Instruction Book 4 26 This Page Left Intentionally Blank ...
Page 187: ...M 3425 Instruction Book 6 50 This Page Left Intentionally Blank ...
Page 207: ...M 3425 Instruction Book C 4 This Page Left Intentionally Blank ...
Page 209: ...D 2 M 3425 Instruction Book Figure D 1 Volts Hz 24 Inverse Curve Family 1 Inverse Square ...
Page 210: ...Inverse Time Curves Appendix D D 3 Figure D 2 Volts Hz 24 Inverse Family Curve 2 ...
Page 211: ...D 4 M 3425 Instruction Book Figure D 3 Volts Hz 24IT Inverse Curve Family 3 ...
Page 212: ...Inverse Time Curves Appendix D D 5 Figure D 4 Volts Hz 24IT Inverse Curve Family 4 ...
Page 215: ...D 8 M 3425 Instruction Book Figure D 5 Definite Time Overcurrent Curve ...
Page 216: ...Inverse Time Curves Appendix D D 9 Figure D 6 Inverse Time Overcurrent Curve ...
Page 217: ...D 10 M 3425 Instruction Book Figure D 7 Very Inverse Time Overcurrent Curve ...
Page 218: ...Inverse Time Curves Appendix D D 11 Figure D 8 Extremely Inverse Time Overcurrent Curve ...
Page 223: ...D 16 M 3425 Instruction Book This Page Intentionally Left Blank ...