A current transformer test set for the audio frequency range

This paper describes the setup of a test set for current transformer (CTTS) calibrations using a two-channel voltage ratio measurement method. A wideband two-channel digitizer and a differential analogue front-end are used as the heart of the ratio measurement system. The front-end suppresses some static errors of the digitizer and is tested for the frequency range up to 200 kHz. Various active or passive shunts adapt the secondary output current to the ± 2 V or ± 10 V input range of the ratio measurement system. Furthermore, the system is used to set up future measurement systems for efficiency measurements in the frame of current European Metrology Programmes (EMRP).