Research on methods to increase the flashover voltage of supporting insulators in Tesla transformers

This paper presents three methods aimed at enhancing the flashover voltage of the supporting insulator in a Tesla transformer. These methods include optimizing the maximum electric field on the insulator surface, adjusting the overall structure of the insulator, and changing the surface structure of the insulator. Ten insulator samples with different structures were designed based on electric field simulation. Subsequent experiments were conducted to validate the effectiveness of these methods in improving flashover voltage. On this basis, the supporting insulator of the Tesla transformer was redesigned, leading to an increased output voltage. The results are summarized in the following. First, optimization of the shielding rings of the cathode and anode reduces the electric field at the triple junction, which significantly increases the flashover voltage. Second, extending the inclination starting position of insulators with the same inclination angle effectively reduces the surface electric field intensity and increases the flashover voltage. Third, increasing the inclination angle within a certain range while keeping the inclination starting position constant extends the creepage distance and enhances the flashover voltage. However, excessively large inclination angles may lead to a decrease in flashover voltage due to excessive normal electric field. Fourth, grooving on the insulator surface at appropriate locations can inhibit the development of the streamer and improve flashover voltage. Finally, the supporting insulator of the Tesla transformer was redesigned based on these results, elevating the output voltage from 750 kV to over 1 MV.