Automatic Reclosing System 79; Program Execution - Siemens 7SC80 Manual

2.14

Automatic Reclosing System 79

From experience, about 85 % of insulation faults associated with overhead lines are arc short circuits which
are temporary in nature and disappear when protection takes effect. This means that the line can be
connected again. The reconnection is accomplished after a dead time via the automatic reclosure function.
If the fault still exists after automatic reclosure (arc has not disappeared, there is a metallic fault), then the
protective elements will re-trip the circuit breaker. In some systems, several reclosing attempts are performed.
Applications
•
The automatic reclosing function integrated in the 7SC80 can also be controlled by an external protection
device (e.g. backup protection). This requires signals to be exchanged between 7SC80 and the external
protection device via binary inputs and outputs.
•
The 7SC80 also works together with an external reclosing device.
•
When operating the 7SC80 on transformers and cables, the function should be disabled.
2.14.1

Program Execution

The 7SC80 is equipped with an integrated three-pole, single-shot and multi-shot automatic reclosure (AR).
Figure 2-100 shows an example of a timing diagram for a successful second reclosure.
[ablaufdiagramm-2-malige-wiedereinschaltung-erfolgreich-260602-kn, 1, en_US]
Figure 2-96
The following figure shows an example of a timing diagram showing for two unsuccessful reclosing shots,
with no additional reclosing of the circuit breaker.
SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017
Timing diagram showing two reclosing shots, first cycle unsuccessful, second cycle successful
Functions
2.14 Automatic Reclosing System 79
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