Determination of Voltage Transformer Errors by Means of a Parallel-Series Step-Up Method

Improvements in the accuracy of determining standard voltage transformer errors by the utilization of specially developed amplifiers are described. Results of recently evaluated measurements in the fundamental parallel-series step-up method of the Physikalisch-Technische Bundesanstalt (PTB) are reported. The overall limit of uncertainty in the calibration of high voltage ratios has been improved by a factor of ten as compared with previous results at power frequencies.