A novel simulation approach for measuring of DC voltage offset influence on magnetizing current even harmonics in the power transformer by using dither

This paper presents stochastic method for measurement of DC voltage offset in 0.4kV distribution network influence on magnetizing current even harmonics presence in the power transformer. Variety of phenomenon, like geomagnetic field, asymmetry of different loads, photovoltaic converters in smart grid, etc. can produce small DC voltage offset in power transformer. Order of magnitude of this offset is around 1mV in 0.4kV distribution network. Such extremely low DC signal level detection (in presence of high AC amplitude) presents challenging measurement task. By using stochastic method, even the direct measurement of such small offset is possible. It is also possible to measure even harmonics of magnetizing current in power transformer in order to measure input voltage DC offset component indirectly, since even harmonics in magnetizing current are consequence of DC component in input voltage.