Functional Diagrams For Protection - ABB REF615 Applications Manual

1MRS756378 D
3.3.3.1
REF615
Application Manual
The analog channels are assigned to different functions as shown in the functional
diagrams. The common signal marked with 3I represents the three phase currents.
The signal marked with I
CT. The signal marked with U
delta connected VTs.
The EFHPTOC protection function block for double (cross-country) earth-faults uses
the calculated residual current originating from the measured phase currents.

Functional diagrams for protection

The following functional diagrams describe the IED's protection functionality in
detail and according to the factory set default connections in SMT.
A071316 V3 EN
Figure 9: Overcurrent protection
represents the measured residual current via a core balance
0
represents the measured residual voltage via open
0
Section 3
REF615 variants
37