
The maximum 3-phase short-circuit current I"
sc
flowing through is (at a source voltage of 1.1 V
N
):
[foglchik-170309-01.tif, 1, en_US]
With a safety margin of 10 %, the following setting value results:
[foglnste-170309-01.tif, 1, en_US]
If short-circuit currents exceed 1496 A (primary) or 12.5 A (secondary), there is a short circuit on the line to be
protected. It can be disconnected immediately.
i
i
NOTE
The calculation was performed with absolute values, which is accurate enough for overhead lines. A
complex calculation is required only if the source impedance and the line impedance have extremely
different angles.
Parameter:
Dropout ratio
•
Recommended setting value
(_:3901:4) Dropout ratio
=
0.90
The recommended setting value of
0.90
is sufficient for many applications. To obtain high-precision measure-
ments, the
Dropout ratio
can be reduced. If you expect highly fluctuating measurands at the pickup
threshold, you can increase the setting value of the parameter
Dropout ratio
. This avoids chattering of the
tripping stage.
Release Procedure via Protection Interface
This stage can be applied only if the device is equipped with a protection interface.
6.9.5
Protection and Automation Functions
6.9 Instantaneous High-Current Tripping
496
SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017
Содержание 7SJ82
Страница 8: ...8 SIPROTEC 5 Overcurrent Protection Manual C53000 G5040 C017 8 Edition 07 2017 ...
Страница 38: ...38 SIPROTEC 5 Overcurrent Protection Manual C53000 G5040 C017 8 Edition 07 2017 ...
Страница 60: ...60 SIPROTEC 5 Overcurrent Protection Manual C53000 G5040 C017 8 Edition 07 2017 ...
Страница 186: ...186 SIPROTEC 5 Overcurrent Protection Manual C53000 G5040 C017 8 Edition 07 2017 ...
Страница 194: ...194 SIPROTEC 5 Overcurrent Protection Manual C53000 G5040 C017 8 Edition 07 2017 ...
Страница 966: ...966 SIPROTEC 5 Overcurrent Protection Manual C53000 G5040 C017 8 Edition 07 2017 ...
Страница 1072: ...1072 SIPROTEC 5 Overcurrent Protection Manual C53000 G5040 C017 8 Edition 07 2017 ...
Страница 1236: ...1236 SIPROTEC 5 Overcurrent Protection Manual C53000 G5040 C017 8 Edition 07 2017 ...
Страница 1306: ...1306 SIPROTEC 5 Overcurrent Protection Manual C53000 G5040 C017 8 Edition 07 2017 ...
Страница 1370: ...1370 SIPROTEC 5 Overcurrent Protection Manual C53000 G5040 C017 8 Edition 07 2017 ...
Страница 1404: ...1404 SIPROTEC 5 Overcurrent Protection Manual C53000 G5040 C017 8 Edition 07 2017 ...
Страница 1576: ...1576 SIPROTEC 5 Overcurrent Protection Manual C53000 G5040 C017 8 Edition 07 2017 ...
Страница 1614: ...1614 SIPROTEC 5 Overcurrent Protection Manual C53000 G5040 C017 8 Edition 07 2017 ...
Страница 1634: ...1634 SIPROTEC 5 Overcurrent Protection Manual C53000 G5040 C017 8 Edition 07 2017 ...