ABB Relion SMU615 Technical Manual page 144

Section 5
Supervision functions
138
GUID-8DC3B17A-13FE-4E38-85C6-A228BC03206B V2 EN
Figure 96: Connection diagram for current circuit supervision with two sets of
three-phase current transformer protection cores
When using the measurement core for reference current
measurement, it should be noted that the saturation level of the
measurement core is much lower than with the protection core. This
should be taken into account when setting the current circuit
supervision function.
1MRS758407 B
SMU615
Technical Manual