Automatic Reclosure Function (Optional); Function Description - Siemens SIPROTEC 7SD610 Manual

2.10

Automatic Reclosure Function (optional)

Experience shows that about 85% of the arc faults on overhead lines are extinguished automatically after being
tripped by the protection. The line can therefore be re-energised. Reclosure is performed by an automatic
reclose function (AR).
Automatic reclosure function is only permitted on overhead lines because the possibility of extinguishing a fault
arc automatically only exists there. It must not be used in any other case. If the protected object consists of a
mixture of overhead lines and other equipment (e.g. overhead line in block with a transformer or overhead
line/cable), it must be ensured that reclosure can only be performed in the event of a fault on the overhead line.
If the circuit breaker poles can be operated individually, a 1-pole automatic reclosure is usually initiated in the
case of 1-phase faults and a 3-pole automatic reclosure in the case of multi-phase faults in the network with
earthed system star point. If the fault still exists after reclosure (arc not extinguished or metallic short-circuit),
the protection issues a final trip. In some systems several reclosing attempts are performed.
In the model with 1-pole tripping the 7SD610 allows phase-selective 1-pole tripping. A 1- and 3-pole, one- and
multi-shot automatic reclosure is integrated depending on the order variant.
The 7SD610 can also operate in conjunction with an external automatic reclosure device. In this case, the
signal exchange between 7SD610 and the external reclosure device must be effected via binary inputs and
outputs.
It is also possible to initiate the integrated auto reclose function by an external protection device (e.g. a backup
protection). The use of two 7SD610 with automatic reclosure function or the use of one 7SD610 with an auto-
matic reclosure function and a second protection with its own automatic reclosure function is also possible.
2.10.1

Function Description

Reclosure is performed by an automatic reclosure circuit (ARC). An example of the normal time sequence of
a double reclosure is shown in the figure below.
Figure 2-44 Timing diagram of a double-shot reclosure with action time (2nd reclosure successful)
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011
2.10 Automatic Reclosure Function (optional)
Functions
125