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Operating modes
Dead-line or
dead-bus closing
Closing at
synchronous
system conditions
7SA6 Manual
C53000-G1176-C156-2
difference Max. Freq. Diff lie outside the permissible limit values. A precondition
for these messages is that voltages within the operating range of the relay are availa-
ble.
The closing check procedure can be selected from the following operating modes:
− SYNC-CHECK
− Usync> U-line<
− Usync< U-line>
− Usync< U-line<
− OVERRIDE
Each of these conditions can be switched to be effective or not effective; combinations
are also possible (e.g. release when Usync> U-line< or Usync< U-line> are sat-
isfied). Combination of OVERRIDE with other parameters is, of course, not meaningful.
The release conditions can be set individually for automatic and for manual closing,
e.g. you can permit manual closing at synchronism or dead line, whilst, before an
automatic reclosure, at one line end only dead line and, at the other, only synchronism
will be permitted.
For release of the closing command to energize a voltage free line from a live bus-bar,
the following conditions are checked:
− Does the feeder voltage U
− Does the bus-bar voltage U
low the maximum operating voltage Umax ?
− Does the bus-bar voltage frequency f
f
± 3 Hz?
N
When the conditions are satisfied, the closing command is released.
Corresponding conditions apply when switching a live line onto a dead bus-bar or a
dead line onto a dead bus-bar.
To release a closing command at synchronous system conditions, the following con-
ditions are checked:
− Does the bus-bar voltage U
low the maximum operating voltage Umax ?
− Does the feeder voltage U
the maximum operating voltage Umax ?
− Does the voltage magnitude difference |U
tolerance Max. Volt. Diff ?
− Do both the frequencies f
f
± 3 Hz?
N
− Does the frequency difference |f
Freq. Diff ?
= Release at synchronism, that is, when the critical values
Max. Volt. Diff , Max. Freq. Diff and Max.
Angle Diff lie within the set limits.
= Release for energized bus-bar (U
gized line (U
<).
line
= Release for de-energized bus-bar (U
gized line (U
>).
line
= Release for de-energized bus-bar (U
gized line (U
<).
line
= Release without any check.
lie below the set value Dead Volt. Thr. ?
line
lie above the set value Live Volt. Thr. , but be-
bus
lie within the permissible operating range
bus
lie above the set value Live Volt. Thr. , but be-
bus
lie above the set value Live Volt. Thr. , but below
line
| – |U
line
and f
lie within the permissible operating range
bus
line
| lie within the permissible tolerance Max.
– f
line
bus
Functions
>) and de-ener-
bus
<) and ener-
bus
<) and de-ener-
bus
| lie within the permissible
bus
6-219
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