Omicron CT SB2 User Manual page 39

Setup and connection
Measurement on a Y (wye) winding transformer
For measurements on current transformers in Y-connected transformer windings it has to be assured
that the main impedance of the transformer does not influence the measurement results.
The input impedance of CT Analyzer may also influence the measurement results. In order to prevent
any influence of the CT Analyzer's input impedance to the measurement results, the transformer winding
at the same leg should be short-circuited. Short-circuiting the windings on all legs of the transformer is
even better.
Furthermore, all bushing terminals that are not connected to CT Analyzer should be connected to
protective earth in order to prevent influence of external disturbances (see Figure 3-11).
Figure 3-11: Measurement on a Y winding transformer
OMICRON 37