NRC-PTB intercomparison of voltage transformer calibration systems for high voltage

An intercomparison of voltage transformer calibration systems was performed at the PTB high voltage laboratory. A "portable" current-comparator-based voltage transformer calibration system of NRC was compared with PTB\´s voltage-divider-based system, using a reference multi-ratio inductive voltage transformer with voltage ratios up to (400 kV//spl radic/3)/(100 V//spl radic/3) as a transfer standard. At frequencies of 50 Hz and 60 Hz with a resistive burden of 10 k/spl Omega/ and test voltages of 20% up to 120% of rated voltage, the test results of the two different methods at all ratios were found to differ by no more than 15/spl times/10/sup -6/ for the voltage ratio and 30 /spl mu/rad for the phase displacement.