Measuring the excitation current in transformers using hall effect sensors

This paper presents and discusses the use of Hall effect sensors to measure the excitation current in single-phase transformers. The Hall effect sensors have galvanic isolation of the order of a few kVrms and may have total measurement errors less than 0.7% of the nominal value. It is common in transformer tests, to use a varivolt to avoid inrush current, which can reach more than 20 times the rated operating current, and can interfere with or even damage electronic circuits for measurement. However with the use of these sensors, their characteristics make it possible to have a measuring device relatively robust, accurate and fast, thus eliminating the use of a varivolt, for testing the load current transformer single phase or three phase.