Measurement Connections; Protection; Auto-Reclosure Function - ABB REX 521 Technical Reference Manual, Standard Configurations

1MRS 751802-MUM
9.4.2.
9.4.3.
9.4.3.1.
Protection Relay
Technical Reference Manual, Standard Configurations

Measurement connections

The three-phase current and neutral current transformers are connected to the
connector X1.1 on the rear panel. The rated currents of the measuring input are 1 A
and 5 A.
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The technical data of the current transformers are set via the Relay Setting Tool or
the local HMI. The settings can be found in
Main menu\Configuration\Meas. devices\. Please refer to Technical
Reference Manual, General (1MRS 751108-MUM) for further information about
how to set the rated currents.

Protection

All the necessary settings for the protection functions can be set via the Relay
Setting Tool or the local HMI. The settings can be found in
Main menu\Protection\.
The following protection functions can be implemented in the same way as in the
first application example (chapter 9.1.):
• overcurrent protection
• earth-fault protection
• phase discontinuity protection
• thermal overload protection

Auto-reclosure function

The auto-reclose function (0->1) enables different types of auto-reclosing. An auto-
reclose sequence is initiated either by a start signal or by a trip signal.
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