Design of 3 MV UV illumination switch

A UV illuminated switch of three sections in series was designed based on UV illumination technology and capacitance-resistance coupling circuit. The switch consists of UV illumination gap and self-breakdown gaps. The distance of self-breakdown gap was calculated based on the experimental data of same switch under pulse with 240 ns risetime. The nonuniform factor of self-breakdown gap is 1.58. The step shield of outer cylinder was used to get the surface field no more than 50 kV/cm. The voltage of UV illumination gap was designed as about 1% of the voltage of self-breakdown gap. It was indicated that the voltage of UV illumination gap is higher than breakdown voltage of rod-rod electrode within 0.1～0.7 MPa.