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.
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: There is a separate setting for the first shot 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.
t1_HS: There is also a separate time setting facility for high-speed auto reclosing,
t1_HS. 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.
Section 12 1MRK 506 375-UEN A
Control
236 Railway application RER670 2.2 IEC
Application manual
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