Set-up of calibration systems for inductive and electronic measurement transformers

Features and performances of a calibration system for both conventional and electronic measurement transformers with analog output are described. The calibration circuit includes standard current/voltage transformers as reference transducers and two synchronised digitizers which enable measurement of signals with amplitude that can differ up to three orders of magnitude. Best measurement uncertainty at power frequency (confidence level 95%) is estimated to be within a few hundreds of ppm and microradians for the ratio and phase error respectively. By making use of different acquisition strategies the same set-up can be employed for the frequency response measurement of transducers up to tens of kilohertz with enlarged uncertainty.