M-3425 Instruction Book
2–30
51T Inverse Time Positive Sequence
Overcurrent (I
2
t=K) for Stator Thermal
Protection
The 51T function is designed to provide overload
protection. The function has a pickup setting and an
operating time at a current value of six (6) times
pickup as shown on Figure 2-14, Inverse Time
Curve — 51T. The inverse time curve is I
2
t=K,
where I is the positive sequence current. This curve
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
)
T
1
5
(
n
o
i
t
c
e
t
o
r
P
l
a
m
r
e
h
T
r
o
t
a
t
S
r
o
f
t
n
e
r
r
u
c
r
e
v
O
e
c
n
e
u
q
e
S
e
v
i
t
i
s
o
P
e
m
i
T
e
s
r
e
v
n
I
p
u
k
c
i
P
A
0
0
.
5
1
o
t
0
5
.
0
)
A
0
0
.
3
o
t
0
1
.
0
(
A
1
0
.
0
*
y
a
l
e
D
e
m
i
T
c
e
S
0
0
.
0
1
o
t
0
1
.
0
e
l
c
y
C
1
s
c
i
t
s
i
r
e
t
c
a
r
a
h
C
t
e
s
e
R
)
r
a
e
n
i
L
(
p
i
r
t
f
o
d
l
o
h
s
e
r
h
t
m
o
r
f
s
e
t
u
n
i
m
4
-
.
t
n
e
r
r
u
c
p
u
k
c
i
p
e
h
t
s
e
m
i
t
x
i
s
t
a
s
i
y
a
l
e
d
e
m
i
t
s
i
h
T
*
Table 2-13
Inverse Time Positive Sequence Overcurrent (51T) Setpoint Ranges
51T PICKUP
________ Amps
51T DELAY @600% PICKUP
________ Sec
This setting is the operating time of the function at six (6) times
pickup value. This is illustrated in Figure 2-14, Inverse Time Curve
51T on the following page, where the operating time for all other
current values may be derived for coordination with other protec-
tions.
is applicable for coordination with the generator
overheating characteristics. In order to handle
recurring overload conditions, the function is provided
with linear reset rate of 4 minutes from its 100% trip
level. Ranges and increments are presented in
Table 2-13.
Содержание M-3425
Страница 1: ...Instruction Book M 3425 Generator Protection ...
Страница 14: ... 13 M 3425 Generator Protection Relay Figure 1 External Connections ...
Страница 33: ...x M 3425 Instruction Book This Page Left Intentionally Blank ...
Страница 89: ...M 3425 Instruction Book 2 52 This Page Left Intentionally Blank ...
Страница 125: ...1 3 A B C M 3425 Instruction Book 4 26 This Page Left Intentionally Blank ...
Страница 187: ...M 3425 Instruction Book 6 50 This Page Left Intentionally Blank ...
Страница 207: ...M 3425 Instruction Book C 4 This Page Left Intentionally Blank ...
Страница 209: ...D 2 M 3425 Instruction Book Figure D 1 Volts Hz 24 Inverse Curve Family 1 Inverse Square ...
Страница 210: ...Inverse Time Curves Appendix D D 3 Figure D 2 Volts Hz 24 Inverse Family Curve 2 ...
Страница 211: ...D 4 M 3425 Instruction Book Figure D 3 Volts Hz 24IT Inverse Curve Family 3 ...
Страница 212: ...Inverse Time Curves Appendix D D 5 Figure D 4 Volts Hz 24IT Inverse Curve Family 4 ...
Страница 215: ...D 8 M 3425 Instruction Book Figure D 5 Definite Time Overcurrent Curve ...
Страница 216: ...Inverse Time Curves Appendix D D 9 Figure D 6 Inverse Time Overcurrent Curve ...
Страница 217: ...D 10 M 3425 Instruction Book Figure D 7 Very Inverse Time Overcurrent Curve ...
Страница 218: ...Inverse Time Curves Appendix D D 11 Figure D 8 Extremely Inverse Time Overcurrent Curve ...
Страница 223: ...D 16 M 3425 Instruction Book This Page Intentionally Left Blank ...