Accuracy of inductive voltage transformer in the presence of voltage high harmonics

In the paper the issue of determining the voltage transformer´s (VT) accuracy when operating with distorted signals is presented. In the measuring system specially designed high impedance differential amplifier and wide frequency voltage divider were used. This enabled the possibility for utilization of the determined values of the composite error for evaluation of the accuracy of VTs in condition of transformation of sinusoidal signals as well as distorted voltages. Comparison of determined values of composite errors for transformation of sinusoidal and distorted voltages allows to designate the additional transformation errors of tested VTs in the presence of voltage high harmonics. Obtained results of measurements indicate that for transformation of distorted voltages tested VTs are characterized by lower transformation accuracy than for power network frequency sinusoidal signal for which they were designed. Moreover, the results of measurements shown the increase of the measured values of the composite error with the increase of the transformed voltage distortion.