Hitachi Relion 670 Series Applications Manual page 226

Section 12
Control
tInhibit: To ensure reliable interruption and temporary blocking of the auto recloser a resetting time
delay tInhibit is used. The auto recloser will be blocked this time after the deactivation of the INHIBIT
input. A typical resetting delay is 5.0 s.
CircuitBreaker settings
CBReadyType: The selection depends on the type of performance available from the circuit breaker
operating gear. At setting OCO (circuit breaker ready for an Open – Close – Open cycle), the
condition is checked only at the start of the auto reclosing cycle. The signal will disappear after
tripping, but the circuit 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.
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 Off.
CutPulse: In circuit breakers without anti-pumping relays, the setting CutPulse = On 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 = On can be used to
avoid repeated closing operations when reclosing onto a fault. A new start will then cut the ongoing
pulse.
tReclaim: 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 tReclaim = 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, tReclaim, 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 "reclaim
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
reclaim time. The auto reclosing sequence is considered unsuccessful and the UNSUCCL output is
activated.
220
© 2017 - 2023 Hitachi Energy. All rights reserved
1MRK506375-UEN Rev. N
Railway application RER670
Application manual