external ground fault. To prevent that, the neutral-point current is rotated in the Transformer neutral-point
function group. It follows that: I
Diff, REF
= |I
4
– I
3
| = 0.
NOTE
If the neutral-point current is included in the protection function (zero-sequence current correction), this
rotation also has an effect for the differential protection.
[dwstwnas-281112-01.tif, 1, en_US]
Figure 6-275
Current-Transformer Connection on the Transformer
The setting of the 1-phase measuring point based on the definition is done as follows:
[scedsall-200214-01, 1, en_US]
Figure 6-276 DIGSI 5 Setting
The point in Figure 6-275 describes the polarity of the current transformer. At the same time, the current
terminal is designed so that this side is fed out on an odd number terminal point. Since in the SIPROTEC 5
system each current transformer can be assigned a 1-phase measuring point, the odd number terminal points
are named in the setting parameters. According to Figure 6-275, the setting must be yes.
•
Default setting (_:115) terminal 1,3,5,7 in dir.obj.= yes
Protection and Automation Functions
6.43 Restricted Ground-Fault Protection
SIPROTEC 5, Overcurrent Protection, Manual 871
C53000-G5040-C017-8, Edition 07.2017
To Next Page
Loading...
