Study on Ultra-high Harmonics Transfer Characteristics of Transformers

Ultra-high harmonics sources such as photovoltaic inverters, charging devices of electric vehicles, lighting equipment are connected to the power grid through transformers, which makes it possible for ultra-high harmonic to flow into the power grid and brings power quality problems to the power grid. The influence of transformer on ultra-high harmonics transmission has become a research hotspot in academia. Considering the distributed capacitance parameters of transformer, a high frequency model of transformer is established and its ultra-high harmonics transfer characteristic function is derived. By comparing the model simulation results with the transformer ultra-high harmonics transfer function deduced by theory, it is found that the distributed capacitance has an effect on the ultra-high harmonics transfer characteristics of transformer, which will provide a direction for analyzing and solving the ultra-high harmonics problems of power grid.