ABB REC670 Applications Manual page 332

Section 14
Control
326
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 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 = On 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.
1MRK 511 401-UEN A
Bay control REC670 2.2 IEC
Application manual