Parameter: V-seal-in threshold
•
Default setting (_:16951:102) V-seal-in threshold = 46.2 V
The V-seal-in threshold (positive-sequence voltage) is set to a value below the lowest phase-to-phase
voltage admissible during an operation, for example 80 % of the rated voltage of a generator. The positive-
sequence voltage is evaluated. The practicable value for a voltage transformer with a rated secondary voltage
of 100 V is 46.2 V.
The following table shows an example of a specification:
Threshold 1.4 * I
rated, Gen
Operate delay 3.00 s
Undervoltage seal-in 0.8 * V
rated, Gen
Duration of V-seal-in time 4.00 s
Dropout ratio 0.95
Rated current I
rated, Gen
483 A Rated voltage V
rated, Gen
6.3 kV
Rated current I
rated, VT, prim
500 A Rated voltage V
rated, VT, prim
6.3 kV
Rated current I
rated, VT, sec
1 A Rated voltage V
rated, VT, sec
100 V
The following secondary setting values result from this specification:
[fo_OCP_UVSI_threshold, 1, en_US]
[fo_OCP_UVSI_Seal-in, 1, en_US]
Parameter: Duration of V-seal-in time
•
Default setting (_:16951:104) Duration of V-seal-in time = 4.00 s
The parameter Duration of V-seal-in time limits the pickup seal-in induced by an overcurrent or
undervoltage. The value must be set higher than the value of the parameter Operate delay. The difference
shall be greater than 0.5 s. In the default setting, a difference of 1 s is used.
Settings
Addr.
Parameter C Setting Options Default Setting
V-seal-in 1
_:16951:1 V-seal-in 1:Mode
•
off
•
on
•
test
off
_:16951:2 V-seal-in 1:Operate &
flt.rec. blocked
•
no
•
yes
no
_:16951:3 V-seal-in 1:Threshold 1 A @ 100 Irated 0.030 A to 35.000 A 1.350 A
5 A @ 100 Irated 0.15 A to 175.00 A 6.75 A
1 A @ 50 Irated 0.030 A to 35.000 A 1.350 A
5 A @ 50 Irated 0.15 A to 175.00 A 6.75 A
1 A @ 1.6 Irated 0.001 A to 1.600 A 1.350 A
5 A @ 1.6 Irated 0.005 A to 8.000 A 6.750 A
_:16951:6 V-seal-in 1:Operate delay 0.00 s to 60.00 s 3.00 s
_:16951:10 V-seal-in 1:Blk. by meas.-
volt. failure
•
no
•
yes
yes
6.4.5.3
Protection and Automation Functions
6.4 Voltage-Dependent Overcurrent Protection, Phases
SIPROTEC 5, Overcurrent Protection, Manual 371
C53000-G5040-C017-8, Edition 07.2017
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