Functions
2.1 General
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A4, Release date 08.2010
35
In DIGSI double-click Settings to open the corresponding dialog box. In doing so, a dialog box with tabs will
open under P.System Data 1 where individual parameters can be configured. The following descriptions
are therefore structured according to these tabs.
Nominal Frequency (Power System)
The nominal frequency of the system is set under the Address 214 Rated Frequency. The factory pre-setting
in accordance with the model need only be changed if the device will be employed for a purpose other than
that which was planned when ordering. In the US device versions (ordering data position 10= C), parameter
214 is preset to 60 Hz.
Phase Rotation (Power System)
Address 209 PHASE SEQ. is used to change the default phase sequence (A B C for clockwise rotation) if your
power system permanently has an anti-clockwise phase sequence (A C B). A temporary reversal of rotation
is also possible using binary inputs (see Section 2.16.2).
Temperature Unit (Power System )
Address 276 TEMP. UNIT allows displaying the temperature values either in degrees Celsius or in degrees
Fahrenheit.
Polarity of Current Transformers (Power System )
At address 201 CT Starpoint, the polarity of the wye-connected current transformers is specified (the fol-
lowing figure applies accordingly to two current transformers). This setting determines the measuring direction
of the device (forward = line direction). Changing this parameter also results in a polarity reversal of the ground
current inputs I
N
or I
NS
.
Figure 2-2 Polarity of current transformers
Current Connection I4 (Power System)
Here, the device is informed whether the ground current of the current transformer neutral point is connected
to the fourth current input (I
4
). This corresponds with the Holmgreen-connection, (see connection example in
Appendix A.3, Figure A-7). In this case, parameter 280 Holmgr. for Σi is set to YES. In all other cases,
even if the ground current of the own line is measured via a separate ground current transformer, the setting
NO has to be made. This setting exclusively affects the function „Current Sum Monitoring“ (see Section 2.10.1)
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