Functions
2.1 General
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A5, Release date 11.2012
40
Figure 2-2 Polarity of current transformers
Current Connection I4 (Power System)
Here, it is communicated to the device whether the ground current of the current transformer neutral point is
connected to the fourth current input (I
4
). This corresponds to the Holmgreen connection, (see connection
example in Appendix A.3,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, enter the
setting NO. This setting exclusively affects the function „Current Sum Monitoring“ (see Section 2.10.1).
Current Connection (Power System Data)
Via parameter 251 CT Connect. a special connection of the current transformers can be determined.
The standard connection is A, B, C, (Gnd). It may only be changed if the device is set to measure one or
more ground currents via two current inputs. The standard connection has to be used in all other cases.
The following picture illustrates such a special connection.
To Next Page
Loading...
