Functions
6-2137SA6 Manual
C53000-G1176-C133-1
The resulting single–phase AC voltage is fed to the two threshold stages 8 and
8 (see Figure 6-109). Combined with the associated time delays 78 and 7
8 these stages form a two-stage undervoltage protection for the positive
sequence system.
Current can be used as an additional criterion for the undervoltage protection of the
positive sequence system (current supervision &855683). An undervoltage is only
detected if the current flow is detected in at least one phase together with the
undervoltage criterion.
The undervoltage protection for the positive sequence system can be blocked via the
binary input “!8%/.”. The stages of the undervoltage protection are
automatically blocked if voltage failure is detected (“Fuse–Failure–Monitor”, also see
Section 6.19.1.3) or, if the trip of the mcb for the voltage transformer is indicated via
the binary input “!)$,/)HHGHU97” (internal blocking).
Figure 6-109 Logic diagram of the undervoltage protection for positive sequence voltage
system
During single-pole dead time for automatic reclosure (using the internal automatic
reclosure function) the stages of the undervoltage protection are automatically
blocked in the positive sequence system so that they do not respond to the reduced
voltage cause by the disconnected phase in case the voltage transformers are located
on the outgoing side.
6.14.2 Applying the Function Parameter Settings
The voltage protection can only operate if it has been set to (QDEOHG during the
configuration of the device scope (see Section 5.1, address ).
The overvoltage and undervoltage stages can detect phase–to–earth voltages,
phase–to–phase voltages or the symmetrical positive sequence system of the
U
L3-E
U
L2-E
U
L1-E
U<
8
T0
78
T U1< TimeOut
U1< Pickup
U<<
T0
78
T U1<< TimeOut
U1<< Pickup
U1<(<) TRIP
≥1
8
>U1<(<) BLK
U
1
U
Ph–E
21
2))
&8556838
„1“
&
&
I–REST> L3
I–REST> L2
I–REST> L1
≥1
FNo 10208
FNo 10300
FNo 10302
FNo 10304
FNo 10303
FNo 10301
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