ABB REB670 Applications Manual page 304

Section 12
Control
298
time, from when the synchronizing is started, even if a synchronizing condition is
fulfilled. A typical setting is 200 ms.
Synchrocheck settings
OperationSC
The OperationSC setting Off disables the synchrocheck function and sets the outputs
AUTOSYOK, MANSYOK, TSTAUTSY and TSTMANSY to low. With the setting On,
the function is in the service 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 VHighBusSC and VHighLineSC have to be set lower than the value
at which the 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-Bus/GblBaseSelBus) - (V-Line/GblBaseSelLine). A normal setting is
0,10-0,15 p.u.
FreqDiffM and FreqDiffA
The frequency difference level settings, FreqDiffM and FreqDiffA, shall be chosen
depending on the condition in the network. At steady conditions a low frequency
difference setting is needed, where the FreqDiffM setting is used. For autoreclosing a
bigger frequency difference setting is preferable, where the FreqDiffA setting is used. A
typical value for FreqDiffM can be10 mHz, and a typical value for FreqDiffA can be
100-200 mHz.
PhaseDiffM and PhaseDiffA
The phase angle difference level settings, PhaseDiffM and PhaseDiffA, shall also be
chosen 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 PhaseDiffA setting.
tSCM and tSCA
The purpose of the timer delay settings, tSCM and tSCA, is to ensure that the synchrocheck
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
1MRK 505 337-UUS -
Application manual