Study of Liquid Nitrogen Insulation Characteristics for Superconducting Transformers

With its great advantage in weight and volume, superconducting transformer is considered as potential candidate for the portable power station. To achieve a more compact design, the insulation properties of liquid nitrogen in real operation state is crucial. This paper firstly presents an AC withstand voltage test of liquid nitrogen under different kinds of electric field. Then the bubble influence on the macroscopic insulation performance of liquid nitrogen is analyzed based on finite element method. In addition, the effect of Sumoto effect at liquid surface is also studied by experiments. The results of this paper can be used in future design of compact superconducting transformers.