A Low-Cost Approach to Generate MV Distorted Voltage for VT Characterization up to 150 kHz

The increase in disturbances at frequencies higher than 10 kHz in medium voltage (MV) grids has led to new metrological challenges related to the accurate characterization of instrument transformers (ITs), which serve as the primary element in the measurement chain for the monitoring of these disturbances. In this context, this article presents a simple architecture of a generation system for the characterization of MV voltage transformers (VTs) up to 150 kHz under realistic power system waveforms. It is able to generate a MV tone at power frequency and superimposed disturbances having reduced amplitude and higher frequency. Unlike other approaches recently discussed in scientific literature that need two separate voltage sources, the main advantage of the proposed solution is the use of a single source, by suitably compensating its systematic errors through a simple compensation method. As first application, the experimental tests related to the characterization of two commercial VTs (LPVT), an inductive VT and a low power VT, are discussed.