Traceability of Low-Power Voltage Transformer for Medium Voltage Application

In this paper, the measuring and calibration techniques useful for ensuring the traceability of nonconventional voltage transformer (VT), used in ac power plant up to 52 kV, are described and discussed. In particular, a setup made by commercially available devices is presented and an in-depth accuracy analysis is performed by considering all the uncertainty sources located in the measurement chain. The obtained results prove that it can be used for the calibration of 0.5 accuracy class low-power VTs. In addition, the sources that contribute more to the uncertainties on the ratio and phase errors are highlighted and suggestions on where to act to further improve the accuracy of the presented setup are given.