Characterization of Voltage Transformers for MV Applications Up to 150 Khz - A Preliminary Study

The advance in the technology of semiconductors has led to the realization of power converters with increased switching frequency. Some technologies available for power converters allow, in addition, their direct connection to the Medium Voltage (MV) grids. This implies the widespread diffusion of high-frequency components, that are harmonics of the components around the switching frequency, also at the MV level. A reliable operation of the MV grids can be guaranteed only if these disturbances are correctly measured. Therefore, increased performance, in terms of accuracy in a wider frequency range, is requested to Instrument Transformers. In this paper, a measurement setup for the characterization of Voltage Transformers (VTs) in the frequency range from power frequency (50/60 Hz) up to 150 kHz is proposed. Some preliminary experimental results related to the characterization of two commercial VTs are also discussed.