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Functions
Undervoltage
Seal–In
2.6.2.1
Settings for the Definite-Time Overcurrent Protection (Stage I>)
Addr.
Setting Title
1201
O/C I>
1202
I>
1203
T I>
1204
U< SEAL-IN
1205
U<
1206
T-SEAL-IN
1207A
I> DOUT RATIO
40
The 1205 U< undervoltage stage (positive-sequence voltage) is set to a value below
the lowest phase-to-phase voltage permissible during operation, e.g. 80 V.
The seal-in time 1206 T-SEAL-IN limits the pickup seal-in introduced by the
overcurrent/undervoltage. It must be set to a value higher than the T I> time delay.
The dropout ratio r = I
PU
1207A I> DOUT RATIO. The recommended value is r = 0.95. For special
applications, e.g. overload warning, it can be set to a higher value (0.98).
Example:
Pickup value
Tripping time delay
Undervoltage seal-in
Seal-in time of U<
Drop-out ratio
Nominal current I
N, Gen
Nominal current I
N, CT, prim
Nominal current I
N, sec
The following secondary setting values result from this specification:
1.4 I ⋅
I>
-----------------------------
=
I
N, CT, prim
0.8 U
U<
------------------------------- -
=
U
N, VT, prim
The following list indicates the setting ranges and the default settings of a I
secondary nominal current. For a secondary nominal current of I
must be multiplied by 5.
Setting Options
OFF
ON
Block relay for trip com-
mands
0.05..20.00 A
0.00..60.00 sec; ∞
ON
OFF
10.0..125.0 V
0.10..60.00 sec
0.90..0.99
/I
of the overcurrent pickup I> is specified at the address
DO
1.4 ⋅ I
N Gen.
3 s
0.8 ⋅ U
N Gen.
4 s
0.95
483 A
Nominal voltage U
500 A
Nominal voltage U
1 A
Nominal voltage U
⋅
1.4 483 A
N, Gen
⋅
--------------------------- - 1 A
I
=
N, sec
500 A
⋅
⋅
0.8 6,3 kV
N, Gen
c ⋅
----------------------------- 100 V
=
6.3 kV
Default Setting
OFF
1.35 A
3.00 sec
OFF
80.0 V
4.00 sec
0.95
6.3 kV
N, Gen
6.3 kV
N, VT, prim
100 V
N, sec
⋅
=
1.35 A
⋅
80 V
=
= 5 A, these values
N
Comments
Overcurrent Time Protection I>
I> Pickup
T I> Time Delay
State of Undervoltage Seal-in
Undervoltage Seal-in Pickup
Duration of Undervoltage Seal-in
I> Drop Out Ratio
7UM62 Manual
C53000-G1176-C149-3
= 1 A
N
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