3MV自耦式紫外预电离开关的设计

Design of 3 MV UV illumination switch

基于紫外预电离技术和阻容耦合电路研制了应用于高功率装置的三串联3MV自耦式紫外预电离开关。该开关由紫外预电离间隙和开关主间隙组成。根据同类开关在脉冲电压下的击穿数据推算出3MV开关的间隙距离，开关主间隙的电场不均匀系数为1．58。采用台阶屏蔽技术使开关有机玻璃筒外沿面最大电场小于50kV／cm，满足设计要求。设计紫外预电离间隙击穿电压为主脉冲电压的1％，理论模拟计算表明，在0．1～0．7MPa范围内，预电离间隙电压大于在此范围内间隙击穿电压，保证可靠预电离。

A UV illuminated switch of three sections in series was designed based on UV illumination technology and capaeitance-resistance coupling circuit. The switch consists of UV illumination gap and selbbreakdown 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.