中文摘要：

表面电荷的积聚会改变电场分布,也会参与放电的电子倍增过程,导致真空绝缘子的沿面闪络电压显著降低。工程中的真空绝缘子是45°圆台形,现有的表面电荷二维测量不能满足研究要求。为研究表面电荷分布特性,研制了表面电荷三维测量平台,获得了表面电荷的三维分布形态。在正极性脉冲电压作用下,表面电荷全部为正,在负极性脉冲电压作用下,表面电荷全部为负。靠近上电极表面电荷密度大。随着脉冲电压幅值和次数的增加,电荷积聚量明显增大。表面电荷的积聚使闪络电压有一定程度的降低。45°圆台绝缘子上电极处的强电场导致的场致发射是表面电荷产生的原因。

英文摘要：

Surface charge is a major factor to flashover in vacuum which can change the distribution of electric field and participate in electron propagation. 45 degree truncated cone insulators are applied in industry, while current surface charge detecting is 2-D which can not meet the research requirement. A novel 3-D surface charge detecting platform for experiment under nanosecond pulse in vacuum was developed. The results show that the surface charge is positive under positive pulse, and negative under negative pulse. Surface charge accumulates in the upper electrode area mostly. Surface charge increases then the flashover voltage decreases as the nanosecond pulse voltage level increases or more strikes are applied. In conclusion, the electric field in the upper electrode of 45 degree truncated cone insulator is enhanced significantly, which leads to electron or hole emission, and that is the cause of surface charge accumulation.