A connection to a single-phase isolated voltage transformer should be avoided, if possible. Particularly, in
isolated or resonant-starpoint-earthed networks an earth fault leads to a voltage value of zero. Thus, on the
one hand you cannot synchronized and on the other hand the bus is identified as dead bus (zero voltage). If
the connection U1< and U2> is allowed, there is a high risk of incorrect synchronization. If the earth fault is
located for example in phase L1, phase L2 is rotated by 30°. Thus, the device synchronizes with a larger angle
error.
[ve6-anschluss-einpol-isoliert-030203-kn, 1, en_GB]
Figure C-6
Connection to a single-phase isolated voltage transformer
Connection Examples
C.2 Voltage Connectors
SIPROTEC 4, 7VE61 and 7VE63, Manual 243
C53000-G1176-C163-3, Edition 10.2017