ABB REC670 Applications Manual page 355

1MRK 511 401-UUS A
Bay control REC670 2.2 ANSI
Application manual
Single-phase auto reclosing dead time: A typical setting is t1 1Ph = 800ms. Due to the
influence of 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
PLCLOST input, and the tExtended t1 setting. Typical setting in such a case: 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 auto reclosing cycle of the slave is inhibited. The maximum wait
time, tWaitForMaster for the second circuit breaker is set longer than the auto
reclosing dead time plus a margin for synchrocheck conditions to be fulfilled for the
first circuit breaker. Typical setting is 2sec.
tSlaveDeadTime: When activating the WAIT input, in the auto recloser set as slave,
every dead timer is changed to the value of setting tSlaveDeadTime and holds back the
Section 14
Control
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