ABB RELION 670 SERIES Applications Manual page 685

1MRK 506 369-UUS -
Line distance protection REL670 2.2 ANSI
Application manual
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 auto
reclosing operation. When the WAIT input is reset at the time of a successful reclosing of
the first circuit breaker, the slave is released to continue the auto reclosing sequence after
the set tSlaveDeadTime. The reason for shortening the time, for the normal dead timers
with the value of tSlaveDeadTime, is to give the slave permission to react almost
immediately when the WAIT input resets. The minimum settable time for tSlaveDeadTime
Section 15
Control
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