Rated Value Of The Primary Object; Additional Parameters - Siemens SIPROTEC 7SJ81 Manual

The LPCT can have a nominal burden higher than the input impedance of
the connected protection devices, e.g. if several devices are connected to
the LPCT. This results in a linear amplitude distortion of the measured
current. Given the shunt resistance of the LPCT, the distortion can be
calculated. The correction factor parameters 320A IL1 Corr.factor,
321A IL2 Corr.factor,
Corr.factor IE und 324A Corr.factor IEE allow compensating
the distortion.

Rated Value of the Primary Object

With the parameter 310 Iph-PRIM ref., you can set the rated current
of the primary object. (This is equivalent to parameter 204 CT PRIMARY
for the 7SJ80).
With the parameter 312 Ignd-PRIM ref., you can set the reference
rated ground current of the object. (This is equivalent to parameter
217 Ignd-CT PRIM for the 7SJ80).

Additional Parameters

With parameter 132 Earth CT, you can set the measuring mode of the
device for ground currents in the menu "Device". If you want to measure
small ground currents using a sensitive low-power current transformer,
use the sensitive setting. If you want to measure large ground currents
using a normal low-power current transformer, use the normal setting.
With parameter 252 Ph LPCT pol., you can set the polarity of the LPCT
currents.
If the parameters settings of the LPCT current measuring inputs are
invalid and impair the protection functionality, the indications 232 CT ph
mismatch or 233 CT gnd mismatch are output.
SIPROTEC 7SJ81/7SK81 V4.70, Product Information
E50417-K1150-C462-A2, Edition 02.2012
322A IL3 Corr.factor, 323A
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