How To Measure Three-phase Current With Two-phase CT

Using two CTs and three ammeters can only measure three-phase symmetrical loads. If the three-phase loads are asymmetrical, the load current of the phase that is not equipped with CTs is inaccurate.

Assume that CT is installed in phase A and C (any two phases are acceptable), at this time, the polarity of CT should be paid attention to when wiring, for example, the primary current of phase A and C is from CT

When the L1 side flows in, the A and C phase CT secondary side K1 terminals are respectively connected to the A and C phase ammeters, and the other two terminals of the A and C phase ammeters are shorted, and then lead a wire to the B phase ammeter, and finally The other terminal of the B-phase ammeter returns to the CT secondary side K2 terminal (the two CT secondary side K2 terminals are shorted together and grounded).