3-phase, 3-wire ARON input connection example

This chapter presents a connection example of an application with protection current transformers for just two phases. Connection is suitable for both motor –and feeder protection applications.

ARON input connection can measure load symmetrically despite the fact that one of the CTs is missing from the installation. Normally the current transformer of phase two is without installed CT since it is much more likely that external fault appears on line 1 or 3.

Fault between line 2 and ground cannot be detected when ARON input connection is used. For detecting ground fault in phase two a cable core CT has to be used.

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