Automatic Reclosing System 79 - Siemens siprotec SJ62 User Manual

2.14

Automatic Reclosing System 79

Applications
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015
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 accom-
plished after a dead time via the automatic reclosing system.
If the fault still exists after automatic reclosure (arc has not disappeared, there is a me-
tallic fault), then the protective elements will re-trip the circuit breaker. In some
systems several reclosing attempts are performed.
• The automatic reclosure system integrated in the 7SJ62/63/64 can also be con-
trolled by an external protection device (e.g. backup protection). For this applica-
tion, an output contact from the tripping relay must be wired to a binary input of the
7SJ62/63/64 relay.
• It is also possible to allow the relay 7SJ62/63/64 to work in conjunction with an ex-
ternal reclosing device.
• The automatic reclosure system can also operate in interaction with the integrated
synchronizing function (only 7SJ64) or with an external synchrocheck.
• Since the automatic reclosing function is not applied when the 7SJ62/63/64 is used
to protect generators, motors, transformers, cables and reactors etc., it should be
disabled for this application.
2.14 Automatic Reclosing System 79
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