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Functions
2.18 Synchronism and Voltage Check (optional)
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
355
WARNING!
Switching under Asynchronous System Conditions!
Closing under asynchronous system conditions requires the closing time of the circuit breaker to be set cor-
rectly in the Power System Data 1 (address
239 ).
Otherwise, faulty synchronization may occur.
General
The synchronism check can only operate if it has been set to
Enabled
and parameter
U4 transformer
(ad-
dress
210
) to
Usy2 transf.
during configuration of the device scope (address
135
).
The measured values of synchronism check (636
„Udiff =“
, 637
„Usy1=“
, 638
„Usy2=“
, 647
„F-diff=“
,
649
„F-sy1 =“
, 646
„F-sy2 =“
and 648
„
ϕ
dif=“
) are only available if the synchronism check is in service.
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 considered a manual reclosure if it was initiated via the
integrated control function or via a serial interface.
The general limit values for synchronism check are set at address
3501
to
3508
. Additionally, addresses
3510
to
3519
are relevant for automatic reclosure, addresses
3530
to
3539
are relevant for manual closure. More-
over, address
3509
is relevant for closure via the integrated control function.
The complete synchronism check function is switched
ON
or
OFF
in address
3501 FCT Synchronism
. If
switched off, the synchronism check does not verify the synchronization conditions and release is not granted.
You can also set
ON:w/o CloseCmd
: the CLOSE command is in this case not included in the common device
alarm
„Relay CLOSE“
(No. 510), but the alarm
„Sync.CloseCmd“
(No. 2961) is issued.
Address
3502 Dead Volt. Thr.
indicates the voltage threshold below which the feeder or the busbar can
safely be considered de-energised (for checking a de-energised feeder or busbar). The setting is applied in
Volts secondary. This value can be entered as a primary value when parameterising with a PC and DIGSI. De-
pending on the VT connection these are phase-to-earth voltages or phase-to-phase voltages.
Address
3503 Live Volt. Thr.
indicates the voltage above which the feeder or busbar is regarded as being
definitely energised (for energised line or busbar check and for the lower limit of synchronism check). It must
be set below the minimum operational undervoltage to be expected. The setting is applied in volts secondary.
This value can be entered as a primary value when parameterising with a PC and DIGSI. Depending on the
connection of the voltages these are phase-to-earth voltages or phase-to-phase voltages.
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 pa-
rameterising with a PC and DIGSI. Depending on the VT connection these are phase-to-earth voltages or
phase-to-phase voltages.
Verification of the release conditions via synchronism check can be limited to a configurable synchronous mon-
itoring time
T-SYN. DURATION
(address
3507
). The configured conditions must be fulfilled within this time. If
not, closure will not be released. If this time is set to
∞
, the conditions will be checked until they are fulfilled or
the measurement request is cancelled.
For switching under synchronous conditions you can specify a delay time
T SYNC-STAB
(address
3508
).
During this time the voltage criteria must at least be fulfilled before closing is released.