2 Functions
146
7ST6 Manual
E50417-G1176-C251-A3
WARNING!
Closing under Asynchronous System Conditions
Closing under asynchronous system conditions requires the closing time of the circuit
breaker to be set correctly in the Power system data 1 (address
239
).
Otherwise, faulty synchronization may occur.
General
The synchro-check can only operate if it has been set to
Enabled
during the config-
uration of the device scope (address
135
Synchro-Check
).
The measured values of the synchro check (636
„Udif=“
, 637
„Uline=“
, 638
„Uref=“
, 647
„fdif=“
, 649
„fline=“
, 646
„fref=“
and 648
„
ϕ
-diff=“
) are
only available if the synchro-check has been set to
Enabled
.
Different interrogation conditions can be parameterized for automatic reclosure on the
one hand and for manual closure on the other hand. Each closing command is con-
sidered a manual reclosure if it was initiated via the integrated control function or via
a serial interface.
The general limit values for closure are set in addresses
3501
to
3508
. For the auto-
matic reclosure function, the addresses
3510
to
3519
are also relevant, and for
manual closure or control closure the addresses
3530
to
3539
. Moreover, address
3509
is relevant for reclosure via the integrated control function.
The complete synchronism check function is switched
ON
or
OFF
in address
3501
FCT
Synchronism
. If switched off, the synchro-check does not verify the synchronization
conditions and release is not granted.
Address
3502
Dead Volt. Thr.
indicates the voltage threshold below which the
feeder or the busbar can safely be considered switched off (for checking a de-ener-
gized feeder or busbar). The setting is applied in Volts secondary. This value can be
entered as a primary value when parameterizing with a PC and DIGSI
®
.
Address
3503
Live Volt. Thr.
shows the voltage above it is safe to assume that
the feeder or the busbar is carrying load. It must be set below the anticipated opera-
tional undervoltage. The setting is applied in Volts secondary. This value can be
entered as a primary value when parameterizing with a PC and DIGSI
®
.
The maximum permissible voltage for the operating range of the synchronism check
function is set in address
3504
Umax
. The setting is applied in Volts secondary. This
value can be entered as a primary value when parameterizing with a PC and DIGSI
®
.
The check of the release conditions through the synchronism check function can be
limited to a configurable synchronous monitoring time
T-SYN. DURATION
(address
3507
). The configured conditions must be fulfilled within this time. Below that, value
reclosure will not be released. If this time is set to
∞
, the conditions will be checked
until they are fulfilled or the measuring request is deactivated.
If the conditions for synchronous operation must be checked to be maintained for a
certain duration, this minimum duration
T SYNC-STAB
can be set in address
3508
.
Synchronism Con-
ditions for Auto-
matic Reclosure
Addresses
3510
to
3519
are relevant to the check conditions before automatic reclo-
sure of the circuit breaker. When setting the parameters for the internal automatic re-
closing function (Section 2.12.2) it was decided whether the synchronism check
should be carried out.
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