ABB Relion 670 Series Applications Manual page 316

Section 14
Control
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
UnsucClByCBChk . The auto reclosing sequence is considered unsuccessful for both above cases
and the
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.
Single-phase auto reclosing dead time: A typical setting is
energized phases the arc extinction may not be instantaneous. In long lines with high voltage the
use of shunt reactors in the form of a star with a neutral reactor improves the arc extinction.
Three-phase auto reclosing dead time: Different local phenomena, such as moisture, salt,
pollution, can influence the required dead time. Some users apply Delayed Auto Reclosing (DAR)
with delays of 10s or more.
Extended t1 : The time extension below is controlled by the Extended t1 setting.
tExtended t1 : A time extension delay, tExtended t1 , can be added to the dead time delay for the
first shot. It is intended to come into use if the communication channel for permissive line
protection is lost. The communication link in a permissive (not strict) line protection scheme, for
instance a power line carrier (PLC) link, may not always be available. If lost, it can result in delayed
tripping at one end of a line. There is a possibility to extend the auto reclosing dead time in such a
case by use of the
Extended t1 = Enabled and tExtended t1 = 0.8 s.
t1 3PhHS : There is also a separate time setting facility for three-phase high-speed auto reclosing,
t1 3PhHS . This high-speed auto reclosing is activated by the STARTHS input and is used when auto
reclosing is done without the requirement of synchrocheck conditions to be fulfilled. A typical
dead time is 400ms.
t2 3Ph , t3 3Ph , t4 3Ph , t5 3Ph : The delay of auto reclosing shot two and possible later shots are
usually set at 30s or more. A check that the circuit breaker duty cycle can manage the selected
setting must be done. The setting can in some cases be restricted by national regulations. For
multiple shots the setting of shots two to five must be longer than the circuit breaker duty cycle
time.
MasterSlave settings
Priority : In single circuit breaker applications, one sets Priority = None. At sequential reclosing the
auto recloser for the first circuit breaker, e.g. near the busbar, is set as master (High) and the auto
recloser for the second circuit breaker is set as slave (Low).
tWaitForMaster : The slave should take the duration of the circuit breaker closing time of the
master into consideration before sending the circuit breaker closing command. A setting
tWaitForMaster sets a maximum wait time for the WAIT input to reset. If the wait time expires, the
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tUnsucCl at the end of the reclaim time. This latter case is controlled by setting
UNSUCCL output is activated.
PLCLOST input, and the tExtended t1 setting. Typical setting in such a case:
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t1 1Ph = 800ms. Due to the influence of
Bay control REC670
1MRK 511 401-UUS F
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