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 Connection
I
4 (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
Σ
i
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).
www
. ElectricalPartManuals
. com