ABB RET670 Applications Manual page 604

Section 3
IED application
598
The phase angle difference level settings, PhaseDiffM and PhaseDiffA, are also chosen
depending on conditions in the network. The phase angle setting must be chosen to
allow closing under maximum load. 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 will be a limitation also for PhaseDiffA as
it is expected that, due to the fluctuations, which can occur at high speed autoreclosing,
the PhaseDiffA is limited in setting.
tSCM and tSCA
The purpose of the timer delay settings, tSCM andtSCA, is to ensure that the
synchrocheck conditions remain constant and that the situation is not due to a
temporary interference. If the conditions do 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. Under stable conditions, a
longer operation time delay setting is needed, where the tSCM setting is used. During
auto-reclosing, a shorter operation time delay setting is preferable, where the tSCA
setting is used. A typical value for tSCM can be 1 second and a typical value for tSCA
can be 0.1 seconds.
Energizingcheck settings
AutoEnerg and ManEnerg
Two different settings can be used for automatic and manual closing of the circuit
breaker. The settings for each of them are:
• Disabled, the energizing function is disabled.
• DLLB, Dead Line Live Bus, the line voltage is below set value of
VDeadLineEnerg and the bus voltage is above set value of VLIveBusEnerg.
• DBLL, Dead Bus Live Line, the bus voltage is below set value of VDeadBusEnerg
and the line voltage is above set value of VLiveLineEnerg.
• Both, energizing can be done in both directions, DLLB or DBLL.
ManEnergDBDL
If the parameter is set to Enabled, manual closing is enabled when both line voltage
and bus voltage are below VDeadLineEnerg and VDeadBusEnerg respectively, and
ManEnerg is set to DLLB, DBLL or Both.
VLiveBusEnerg and VLiveLineEnerg
The voltage level settings must be chosen in relation to the bus or line network voltage.
The threshold voltages VLiveBusEnerg and VLiveLineEnerg have to be set lower than
the value at which the network is considered to be energized. A typical value can be
80% of the base voltages.
1MRK504116-UUS C
Application manual