Metrological determination of the frequency response of inductive voltage transformers up to 20 kHz

The use of power electronics and other assets with a nonlinear impedance characteristic causes harmonics in the electrical grid which should be monitored to keep the power quality at a high level. System operators connect their secondary equipment mainly to inductive voltage transformers that may have resonances in the frequency range of interest. Therefore, the influence of a voltage transformer itself on the PQ measurement has to be assessed, especially since they have some advantages compared to other technologies. Thereby, it is important to be able to measure the frequency response with a low measurement error. As shown in this work, several external factors can influence the measurement results to a great extent. Therefore, it should be known which variables affect the frequency behavior. Several influences are analyzed in this work and their impact on the frequency response is displayed.