Siemens Siprotec 7UM611 Manual page 261

• Check control circuits from the output relays via control lines to the circuit breakers
• Check binary input signals via signal lines up to the protection device by activating
Protective Switch- Since it is very important for the undervoltage protection, impedance protection and
es for the Voltage voltage-dependent definite time and inverse time overcurrent protection that these
Transformers functions are blocked automatically if the circuit breaker for the voltage transformers
has tripped, the blocking should be checked along with the voltage circuits. Switch off
voltage transformer protection switches.
Check in the operational messages that the VT mcb trip was entered (indication
">FAIL:Feeder VT" "ON"). A requirement for this is that the auxiliary contact of the
VT mcb is connected and correspondingly allocated.
Close the VT mcb again: The above indications appear under the "going" operational
indications, i.e. with the comment "OFF" (e.g. ">FAIL:Feeder VT" "OFF").
Note
The definite time overcurrent with undervoltage seal-in blocking must be realized with
the input ">Useal-in BLK"(FNo. 1950).
If one of the indications does not appear, check the connection and allocation of these
signals.
If the "ON" comment and "OFF" comment are interchanged, the contact type (normally
closed or normally opened) must be checked and corrected.
7UM61 Manual
C53000-G1176-C127-3
and isolators etc.
the external contacts.
3.2 Checking Connections
261