Siemens SIPROTEC 4 Manual page 270

Functions
2.20 Synchrocheck
[sync-mehrphasig-anschl-061116, 1, en_US]
Figure 2-118
If only phase-to-ground voltages are available, the reference voltage V
former and the additional voltage V
[sync-1phasig-anschl-le-061116, 1, en_US]
Figure 2-119
270
Phase-to-phase voltage connection (open-delta connection)
to the third voltage transformer.
2
Phase-to-ground voltage connection
is connected to the first voltage trans-
1
SIPROTEC 4, 7SJ80, Manual
E50417-G1140-C343-A8, Edition 12.2017