基于一台长脉冲低阻抗强流相对论电子束加速器，对聚四氟乙烯、高分子量聚乙烯和聚碳酸酯在真空百ns高压脉冲下的绝缘特性进行了测量,重点研究了周期刻槽结构对材料绝缘强度的提升能力。实验表明：刻槽结构的引入可以有效地提高介质材料的闪络时延；聚碳酸酯是3种材料中比较优越的一个，刻槽处理可以使其闪络延时获得90%左右的提升。扫描电镜分析的结果也表明材料的表面特性是影响介质样品闪络时延的一个重要因素。

With a long pulse low impedance electron-beam accelerator, the insulating properties of polytetrafluoroethylene (PTFE)， high molecular weight polyethylene (PE) and polycarbonate (PC) are measured in vacuum by the excitation of ～100 ns high-voltage pulses. The effect of grooved structure on enhancing the insulating strength is studied. Experimental results show that flashover delay time can be promisingly increased with proper grooved structure. PC is the most competent dielectric among the three tested materials, its flashover delay time can be increased by 90% with the grooved structure. The analysis by a scanning electron microscope (SEM) also shows that the surface properties of the materials, such as the roughness and homogeneity, are important in initiating a surface flashover.