2.12 Automatic Reclosure Function
135
7ST6 Manual
E50417-G1176-C251-A3
TRIP out of Action
Time
The interval between the appearance of a pickup signal and the appearance of a TRIP
command can be monitored by the action time in addresses
3431
1.AR: T-ACTION
and
3441
2-8 Recl:T SI
. The action time starts with the appearance of the pickup
signal. If the action time expires without a TRIP command arriving, each TRIP
command in the time between the expiry of the action time and the reset of the pickup
leads to a dynamic blocking of the auto reclose function. The "blocked" signal starts
the dynamic blocking time. The auto reclose function resumes normal state when the
blocking time has expired and new blocking conditions do not apply.
Start Signal Moni-
toring Time Expired
The interval between the appearance of the TRIP command and the opening of the
circuit breaker is monitored by means of the start signal monitoring time set in address
3416
T-Start MONITOR
. If the time expires before the circuit breaker has opened,
the auto reclose function is dynamically blocked and the dynamic blocking time
launched. The auto reclose function resumes normal state when the blocking time has
expired and new blocking conditions do not apply.
Dead Time Exten-
sion Expired
The monitoring of the circuit breaker ready signal and the synchro-check may cause
undesired extension of the dead time. To prevent the automatic reclosure system from
assuming an undefined state, the extension of the dead time is monitored. The exten-
sion time (address
3421
T-DEAD EXT.
) is launched when the regular dead time has
expired. When it has expired, the automatic reclosure function is blocked dynamically
and the dynamic blocking time launched. The auto reclose function resumes its
normal state when the blocking time has expired and new blocking conditions do not
apply.
Circuit Breaker
Ready Monitoring
Time Expired /
Reclaim Time
Expired without CB
CLOSE
If the setting of address
3415
CB? 1.TRIP
specifies that the circuit breaker readiness
is to be monitored during the dead time, the timer for the circuit breaker ready moni-
toring (
3417
CB TIME OUT
) is launched within the pause when the binary input indi-
cation2730
„>CB Ready“
disappears. If it expires without the binary input signal re-
turning, the auto reclose function is dynamically blocked, and the blocking time of 500
ms is launched. The auto reclose function resumes its normal state when the blocking
time has expired and new blocking conditions do not apply. If the reclaim time, plus,
where applicable, the CLOSE command time, expires without the circuit breaker being
closed, the auto reclose function is also dynamically blocked.
Blocking by Pickup
in Reverse Direc-
tion
In the case of a pickup by any of the internal protection functions, the general auto
reclose function can be dynamically blocked in dependence on parameter
3413
AR
BLK REVERSE
) if the distance protection detects a fault in reverse direction. The auto
reclose function resumes normal state when the blocking time has expired and new
blocking conditions do not apply.
Current Limit
Reached
When the fault current reaches a settable limit
I LIMIT BLK
(address
3411
), a
started automatic reclosure is dynamically blocked. The auto reclose function
resumes its normal state when the blocking time of 500 ms has expired and new block-
ing conditions do not apply.
Blocking of the
Thermal Auto
Reclose Function
by Pickup of
another Protection
Function
If the automatic reclosure function is active (actuated by the thermal overload function)
and trips another protection function, the auto reclose function is dynamically blocked.
The blocking is reset as soon as the dynamic blocking has expired.
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