Siemens SIPROTEC 4 7SD80 Manual page 37

[polung-stromwandler-020313-kn, 1, en_US]
Figure 2-2
Nominal Values of Transformers
In addresses 203 Vnom PRIMARY and 204 Vnom SECONDARY the device obtains information on the primary
and secondary rated voltage (phase-to-phase voltage) of the voltage transformers and in addresses 205 CT
PRIMARY and 206 CT SECONDARY the information on the primary and secondary rated current of the current
transformers (phases).
The voltage connection is required for all functions that work on the basis of power or voltage values, e.g.
ground fault differential protection in resonant-grounded/isolated systems, directional overcurrent protection,
voltage protection, frequency protection, and to display and record the voltages.
Please make sure that the rated secondary transformer current matches the rated current of the device.
Correct entry of the primary data is a prerequisite for the correct computation of operational measured values
with primary magnitude. If the settings of the device are performed with primary values using DIGSI, these
primary data are an indispensable requirement for the correct function of the device.
Current Connection
The device features four current measurement inputs, three of which are connected to the set of current
transformers. Various possibilities exist for the fourth current input Ι
•
Connection of the Ι
the protected feeder (normal connection, see Appendix
Address 220 is then set to: I4 transformer = In prot. line and address 221 I4/Iph CT = 1.
•
Connection of the Ι
tion CT or core balance CT, see Appendix
Address 220 is then set to: I4 transformer = In prot. line and Address 221 I4/Iph CT is set:
[uebersetzung-erd-phase-260702-wlk, 1, en_US]
Example:
Phase current transformers 500 A / 5 A
Core balance 60 A / 1 A
[formel-strmwdl-parallelschlt-270702-wlk, 1, en_US]
SIPROTEC 4, 7SD80, Manual
E50417-G1100-C474-A2, Edition 02.2018
Polarity of current transformers
input to the ground current in the neutral point of the set of current transformers on
4
input to a separate ground current transformer on the protected line (e.g. a summa-
4
:
4
C Connection
C Connection Examples):
2.1 General
Examples):
Functions
37