Siemens SIPROTEC 4 7SD80, Manual

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[lo-crossblk-fkt-1ende-110428, 1, en_US]
Figure 2-33 Logic diagram of the cross-block function for one end
Setting Notes
The inrush current detection is required for the following applications:
•
For the differential protection if an inductance is located in the protected zone.
•
For the time overcurrent protection if the protected line ends on a transformer.
Inrush current detection can be turned
ON
or
OFF
at address 2301
INRUSH REST.
.
It is based on the evaluation of the second harmonic which exists in the inrush current. Ex-works a ratio of
15 % of the
2nd HARMONIC
Ι
2fN
/
Ι
fN
is set under address 2302, which can normally be taken over. However,
the component required for restraint can be parameterized. In order to be able to achieve a higher degree of
restraint in case of exceptionally unfavorable inrush conditions, you may also set a smaller value.
However, if the local measured current exceeds a value set in address 2305
MAX INRUSH PEAK
, there will be
no inrush restraint. The peak value is decisive. The set value should be higher than the maximum inrush
current peak value that can be expected. For transformers set the value above √2·
Ι
NTransf
/u
kTransf
. If a line ends
on a transformer, a smaller value may be selected, considering the damping of the current by the line impe-
dance.
The crossblock function can be activated (
YES
or deactivated (
NO
) in address 2303
CROSS BLOCK
. The time
after exceeding of the current threshold for which this crossblock is to be activated is set under address 2310
CROSSB 2HM
. With the setting ∞ the crossblock function is always active until the second harmonic content in
all phases has dropped below the set value.
Settings
Addr. Parameter Setting Options Default Setting Comments
2301 INRUSH REST. OFF
ON OFF Inrush Restraint
2302 2nd HARMONIC 10 .. 45 % 15 % 2nd. harmonic in % of funda-
mental
2303 CROSS BLOCK NO
YES NO Cross Block
2305 MAX INRUSH PEAK 5.5 .. 125.0 A 75.0 A Maximum inrush-peak value
2310 CROSSB 2HM 0.00 .. 60.00 sec 0.00 sec Time for Crossblock with 2nd
harmonic
2.5.2
2.5.3
Functions
2.5 InRush Restraint
92 SIPROTEC 4, 7SD80, Manual
E50417-G1100-C474-A2, Edition 02.2018