Aided Def Por Scheme - GE MiCOM P40 Technical Manual

Chapter 8 - Carrier Aided Schemes
Note:
The Aided DEF Reverse setting has to be above the maximum steady state residual current imbalance.
5.5

AIDED DEF POR SCHEME

The scheme has the same features and requirements as the corresponding Distance scheme and provides
sensitive protection for high resistance earth faults.
The signalling channel is keyed from operation of the forward DEF Fwd Set element. If the remote device has also
detected a forward fault, it operates with no additional delay when it receives this signal.
The logic is:
Send logic: Key channel if DEF Fwd Set picks up
●
● Permissive trip logic: Trip if DEF Fwd Set picks up AND the channel key is received
The figure below shows the element reaches, and the simplified scheme logic of the Aided DEF POR scheme.
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P446SV
P446SV-TM-EN-1