ABB RELION RET670 Applications Manual page 702

Section 15
Control
696
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 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 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 also 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.
VDeadBusEnerg and VDeadLineEnerg
1MRK 504 163-UUS A
Transformer protection RET670 2.2 ANSI
Application manual