Calibrating an Instrument Voltage Transformer to achieve reduced uncertainty

This paper describes the use of a lock-in amplifier to determine the error between a standard Instrument Voltage Transformer and the Instrument Voltage Transformer (IVT) that is being tested. The method reduces the uncertainty of the measured IVT errors in comparison with commercially produced devices. In addition, we describe an IVT calibration method for different primary voltage values of a standard IVT and the calibrated IVT. When there are different transformation ratios, special inductive dividers (ID) are used which match the secondary voltages of the two IVTs at the same value.