ABB Relion 670 Series Applications Manual page 274

Section 13
Control
seconds. If the network frequencies are expected to be outside the limits from the start, a margin
needs to be added. A typical setting is 600 seconds.
tMinSynch
The setting
attempt is given. The synchronizing function will not give a closing command within this time,
from when the synchronizing is started, even if a synchronizing condition is fulfilled. A typical
setting is 200 ms.
Synchrocheck settings
OperationSC
OperationSC setting Off disables the synchrocheck function and sets the outputs AUTOSYOK,
The
MANSYOK, TSTAUTSY and TSTMANSY to low. With the setting
mode and the output signal depends on the input conditions.
VHighBusSC and VHighLineSC
The voltage level settings must be chosen in relation to the bus or line network voltage. The
threshold voltages
breaker is expected to close with the synchronism check. A typical value can be 80% of the base
voltages.
VDiffSC
The setting for voltage difference between line and bus in p.u. This setting in p.u. is defined as (V-
GblBaseSelBus ) - (V-Line/ GblBaseSelLine ). A normal setting is 0,10-0,15 p.u.
Bus/
FreqDiffM and FreqDiffA
The frequency difference level settings,
the condition in the network. At steady conditions a low frequency difference setting is needed,
where the
preferable, where the
typical value for
PhaseDiffM and PhaseDiffA
The phase angle difference level settings,
depending on conditions in the network. The phase angle setting must be chosen to allow closing
under maximum load condition. A typical maximum value in heavy-loaded networks can be 45
degrees, whereas in most networks the maximum occurring angle is below 25 degrees. The
PhaseDiffM setting is a limitation to PhaseDiffA setting. Fluctuations occurring at high speed
autoreclosing limit
tSCM and tSCA
The purpose of the timer delay settings,
conditions remains constant and that the situation is not due to a temporary interference. Should
the conditions not persist for the specified time, the delay timer is reset and the procedure is
restarted when the conditions are fulfilled again. Circuit breaker closing is thus not permitted until
the synchrocheck situation has remained constant throughout the set delay setting time. Manual
closing is normally under more stable conditions and a longer operation time delay setting is
needed, where the
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tMinSynch is set to limit the minimum time at which the synchronizing closing
VHighBusSC and VHighLineSC have to be set lower than the value at which the
FreqDiffM setting is used. For autoreclosing a bigger frequency difference setting is
FreqDiffA setting is used. A typical value for FreqDiffM can be10 mHz, and a
FreqDiffA can be 100-200 mHz.
PhaseDiffA setting.
tSCM setting is used. During auto-reclosing, a shorter operation time delay
On , the function is in the service
FreqDiffM and FreqDiffA , shall be chosen depending on
PhaseDiffM and PhaseDiffA , shall also be chosen
tSCM and tSCA , is to ensure that the synchrocheck
1MRK 511 358-UUS A
Application manual