Functions
2.14 Automatic Reclosing System 79
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
250
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 reclosing system.
If the fault still exists after automatic reclosure (arc has not disappeared, there is a metallic fault), then the pro-
tective elements will re-trip the circuit breaker. In some systems several reclosing attempts are performed.
Applications
• The automatic reclosure system integrated in the 7SJ62/64 can also be controlled by an external protection
device (e.g. backup protection). For this application, a signal exchange must occur between 7SJ62/64 and
the external protection device via binary inputs and outputs.
• It is also possible to allow the relay 7SJ62/64 to work in conjunction with an external reclosing device.
• The automatic reclosure system can also operate in interaction with the integrated synchronization function
or with an external synchrocheck.
• Since the automatic reclosing function is not applied when the 7SJ62/64 is used to protect generators,
motors, transformers, cables and reactors etc., it should be disabled for this application.
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