Automatic Reclosing System 79 - Siemens SIPROTEC 7SJ62 Manual

Multi-functional protective relay with local control

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2.14 Automatic Reclosing System 79

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.

SIPROTEC, 7SJ62/64, Manual

C53000-G1140-C207-2, Release date 01.2008