ABB REB670 Applications Manual page 345

1MRK 505 370-UUS A
Busbar protection REB670 2.2 ANSI
Application manual
pulse setting may facilitate dynamic indication at testing, for example, in debug mode
of the Application Configuration Tool (ACT) in PCM600. In circuit breakers without
anti-pumping relays, the setting CutPulse = Enabled can be used to avoid repeated
closing operations when reclosing onto a fault. A new start will then cut the ongoing
pulse.
tReset: The reclaim time sets the time for resetting the function to its original state,
after which a line fault and tripping will be treated as an independent new case with a
new auto reclosing cycle. One may consider a nominal CB duty cycle of for instance,
O – 0.3sec – CO – 3min – CO. However the 3 minute (180 s) recovery time is usually
not critical as fault levels are mostly lower than rated value and the risk of a new fault
within a short time is negligible. A typical time may be tReset = 60 or 180 s dependent
on the fault level and circuit breaker duty cycle.
tSync: Maximum wait time for fulfilled synchrocheck conditions. The time window
should be coordinated with the operate time and other settings of the synchrocheck
function. Attention should also be paid to the possibility of a power swing when
reclosing after a line fault. Too short a time may prevent a potentially successful auto
reclosing.
tCBClosedMin: A typical setting is 5.0 s. If the circuit breaker has not been closed for
at least this minimum time, an auto reclosing start will not be accepted.
tSuccessful: If the circuit breaker closing command is given and the circuit breaker is
closed within the set time interval tUnsucCl, the SUCCL output is activated after the
set time interval tSuccessful.
tUnsucCl: The reclaim timer, tReset, is started each time a circuit breaker closing
command is given. If no start occurs within this time, the auto recloser will reset. A
new start received in "restart time" status will reenter the auto recloser to "in progress"
status as long as the final shot is not reached. The auto recloser will reset and enter
"inactive" status if a new start is given during the final restart time. This will also
happen if the circuit breaker has not closed within set time interval tUnsucCl at the end
of the reclaim time. This latter case is controlled by setting UnsucClByCBChk. The
auto reclosing sequence is considered unsuccessful for both above cases and the
UNSUCCL output is activated.
DeadTime settings
NoOfShots: In power transmission one shot is mostly used. In most cases one auto
reclosing shot is sufficient as the majority of arcing faults will cease after the first auto
reclosing shot. In power systems with many other types of faults caused by other
phenomena, for example wind, a greater number of auto reclosing attempts (shots) can
be motivated.
t1 1Ph, t1 2Ph, t1 3Ph: There are separate settings for the first shot for single-, two-
and three-phase auto reclosing dead times.
Section 12
Control
339