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Functions
2.17 Automatic Reclosure Function (optional)
The blocking duration following manual-close detection T-BLOCK MC (address 3404) must ensure the circuit
breaker to open and close reliably (0.5 s to 1 s). If a fault is detected by a protection function within this time
after closing of the circuit breaker was detected, no reclosure takes place and a final 3-pole trip command is
issued. If this is not desired, address 3404 is set to 0.
The options for handling evolving faults are described in Section 2.17 under margin heading „Handling Evolving
Faults". The treatment of sequential faults is not necessary on line ends where the adaptive dead time is applied
(address 133 Auto Reclose = ADT). The addresses 3406 and 3407 are then of no consequence and there-
fore not accessible.
The detection of an evolving fault can be defined under address 3406 EV. FLT. RECOG.. EV. FLT.
RECOG. with PICKUP means that, during a dead time, every pickup of a protection function will be interpret-
ed as an evolving fault. With EV. FLT. RECOG. with TRIP a fault during a dead time is only interpreted as
an evolving fault if it has led to a trip command by a protection function. This may also include trip commands
which are received from an external device via a binary input or which have been transmitted from another end
of the protected object. If an external protection device operates together with the internal auto-reclosure,
evolving fault detection with pickup presupposes that a pickup signal from the external device is also connected
to the 7SD5; otherwise an evolving fault can only be detected with the external trip command even if with
PICKUP was set here.
The reaction in response to sequential faults can be selected at address 3407. EV. FLT. MODE Stops
AutoRecl means that no reclosure is performed after detection of a sequential fault. This is always useful
when only 1-pole reclosure is to take place or when stability problems are expected due to the subsequent 3-
pole dead time. If a 3-pole reclose cycle is to be initiated by tripping of the sequential fault, set EV. FLT. MODE
= starts 3p AR. In this case a separately adjustable 3-pole dead time is started with the 3-pole trip command
due to the sequential fault. This is only useful if 3-pole reclosure is also permitted.
Address 3408 T-Start MONITOR monitors the reaction of the circuit breaker after a trip command. If the CB
has not opened during this time (from the beginning of the trip command), the automatic reclosure is blocked
dynamically. The criterion for circuit breaker opening is the position of the circuit breaker auxiliary contact or
the disappearance of the trip command. If a circuit breaker failure protection (internal or external) is used on
the feeder, this time should be shorter than the delay time of the circuit breaker failure protection so that no
reclosure takes place if the circuit breaker fails.
Note
If the circuit breaker failure protection (BF) should perform a 1-pole TRIP repetition, the time setting of param-
eter 3408 T-Start MONITOR must be longer than the time set for parameter 3903 1p-RETRIP (T1).
To enable that the busbar is tripped by the circuit breaker failure protection without preceding 3-pole coupling
of the trip command (by AR or BF), the time set for 3408 T-Start MONITOR also has to be longer than the
time set for 3906 T2. In this case, the AR must be blocked by a signal from the BF to prevent the AR from
reclosing after a busbar TRIP. It is recommended to connect the signal 1494 „BF T2-TRIP(bus)" to the AR
input 2703 „>AR block" by means of CFC.
If the reclosure command is transmitted to the opposite end, this transmission can be delayed by the time
setting in address 3410 T RemoteClose. This transmission is only possible if the device operates with adap-
tive dead time at the remote end (address 133 Auto Reclose = ADT). This parameter is otherwise irrelevant.
On the one hand, this delay serves to prevent the remote end device from reclosing unnecessarily when local
reclosure is unsuccessful. On the other hand, it should be noted that the line is not available for energy trans-
port until the remote end has also closed. Therefore this delay must be added to the dead time for consideration
of the network stability.
336
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
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