2 Functions
44
7UM61 Manual
C53000-G1176-C127-3
Undervoltage Seal-
In
The 1205 U< undervoltage stage (positive-sequence voltage) is set to a value below
the lowest phase-to-phase voltage admissible during operation, e.g. 80 V.
The seal-in time 1206 T-SEAL-IN limits the pickup seal-in introduced by the overcur-
rent/undervoltage. It must be set to a value higher than the T I> time delay.
The dropout ratio r = I
off
/I
on
of the overcurrent pickup I> is specified at address 1207
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).
Examples:
The following secondary setting values result from this specification:
2.6.3 Settings
Addresses which have an appended "A" can only be changed with DIGSI, under Ad-
ditional Settings.
The table indicates region-specific presettings. Column C (configuration) indicates the
corresponding secondary nominal current of the current transformer.
Pick-up thresh-
old
1.4 · I
N Mach.
Trip Time Delay 3 sec
Undervoltage
Seal-In
0.8 · I
N Mach.
Holding time of
U<
4 sec
Dropout Ratio 0.95
Rated current IN,
Mach
483 A Rated voltage
U
N, Mach
6.3 kV
Rated current IN,
CT, prim
500 A Rated voltage U
N
VT. prim
6.3 kV
Rated current IN,
sec
1 A Rated voltage
U
N, sec
100 V
Addr. Parameter C Setting Options Default Setting Comments
1201 O/C I> OFF
ON
Block relay
OFF Overcurrent Time Protec-
tion I>
1202 I> 1A 0.05 .. 20.00 A 1.35 A I> Pickup
5A 0.25 .. 100.00 A 6.75 A
1203 T I> 0.00 .. 60.00 sec; ∞ 3.00 sec T I> Time Delay
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