ABB Relion 670 Series Applications Manual page 304

Section 12
Control
breaker will still be able to perform the C-O sequence. For the selection CO (circuit breaker ready for a
Close – Open cycle) the condition is also checked after the set auto reclosing dead time. This selection
has a value first of all at multi-shot auto reclosing to ensure that the circuit breaker is ready for a C-O
sequence at shot two and further shots. During single-shot auto reclosing, the OCO selection can be
used. A breaker shall according to its duty cycle always have storing energy for a CO operation after the
first trip. (IEC 56 duty cycle is O – 0.3sec – CO – 3min – CO).
FollowCB: The usual setting is Follow CB = Off. The setting On can be used for delayed auto reclosing
with long delay, to cover the case when a circuit breaker is being manually closed during the auto
reclosing dead time before the auto recloser has issued its breaker close command.
UnsucClByCBChk: The normal setting is NoCBCheck and the auto reclosing unsuccessful event is then
decided by a new trip within the reclaim time after the last reclosing shot. If one wants to get the
UNSUCCL (Reclosing is unsuccessful) signal in the case the circuit breaker does not respond to the
circuit breaker close command, one can set UnsucClByCBCheck = CB Check and set tUnsucCl for
instance to 1.0 s.
BlockByUnsucCl: Setting of whether an unsuccessful auto reclosing attempt shall set the auto recloser in
blocked status. If used the BLKOFF input must be configured to unblock the function after an
unsuccessful auto reclosing attempt. Normal setting is Disabled.
CutPulse: In circuit breakers without anti-pumping relays, the setting CutPulse = Enabled can be used to
avoid repeated closing operation when reclosing onto a fault. A new start will then cut the ongoing pulse.
tPulse: The circuit breaker closing command should be long enough to ensure reliable operation of the
circuit breaker. The circuit breaker closing command pulse has a duration set by the tPulse setting. A
typical setting may be tPulse = 200 ms. A longer 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.
298
© 2017 - 2021 Hitachi Power Grids. All rights reserved
1MRK 505 370-UUS Rev. K
Busbar protection REB670
Application manual