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:
•
Off
, the energizing function is disabled.
•
DLLB
, Dead Line Live Bus, the line voltage is below set value of
ULowLineEnerg
and the bus voltage is above set value of
UHighBusEnerg
.
•
DBLL
, Dead Bus Live Line, the bus voltage is below set value of
ULowBusEnerg
and the line voltage is above set value of
UHighLineEnerg
.
•
Both
, energizing can be done in both directions,
DLLB
or
DBLL
.
ManEnergDBDL
If the parameter is set to
On
, manual closing is also enabled when both line voltage
and bus voltage are below
ULowLineEnerg
and
ULowBusEnerg
respectively, and
ManEnerg
is set to
DLLB
,
DBLL
or
Both
.
UHighBusEnerg
and
UHighLineEnerg
The voltage level settings must be chosen in relation to the bus or line network
voltage. The threshold voltages
UHighBusEnerg
and
UHighLineEnerg
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.
ULowBusEnerg
and
ULowLineEnerg
The threshold voltages
ULowBusEnerg
and
ULowLineEnerg
, have to be set to a
value greater than the value where the network is considered not to be energized. A
typical value can be 40% of the base voltages.
A disconnected line can have a considerable potential due to, for
instance, induction from a line running in parallel, or by being fed
Section 12
1MRK 505 393-UEN B
Control
228
Line differential protection RED650 2.2 IEC
Application manual
Summary of Contents for RED650
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