Functions
2.1 General
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
44
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 ConnectionI4 (Power System Data)
Here, the device is informed whether the ground current of the current transformer starpoint is connected to the
fourth current input (I
4
). This corresponds with the Holmgreen-connection, (see connection example in Appen-
dix A.3, Figure A-37). 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 2.11.1).
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