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为深入探讨A12O3掺杂环氧树脂这种重要绝缘材料在SF6气体中的直流沿面闪络特性,搭建了直流闪络电压测试系统,测量了0.4 MPa SF6气体中不同Al2O3含量环氧树脂(A12O3和环氧树脂的质量比为2.5～4.0)试样的短时和长时耐受电压及作用时间,对比分析了短时和长时电压作用下的伏秒(U-t)特征,通过闪络通道痕迹和材料微观结构分析研究了放电对A12O3掺杂环氧树脂的损伤破坏,并讨论分析了沿面放电中虫孔的形成及其对闪络过程的影响.研究结果显示:特定A12O3含量环氧树脂的耐受电压随电压作用时间的增加呈指数下降,且长时耐受电压比短时耐受电压低20％～30％,A12O3和环氧树脂的质量比为3.5时,环氧树脂短时耐受和长时耐受电压最低,且炭化痕迹最为显著.在环氧树脂表面闪络通道中存在明显的虫孔,且随A12O3含量增加,浅表层虫孔逐步转变为深层虫孔,表明随着A12O3含量增加闪络路径逐步由沿面放电形式过渡为体击穿形式,二者之间A12O3和环氧树脂的质量比临界值约为3.0～3.5.“,”In order to study the DC flashover characteristics in SF6 of alumina filled epoxy resin,which is one of the important insulating materials,DC flashover voltage test system is established.The short-term and long-term withstand voltages of epoxy resin samples with various alumina contents (mass ratio range of epoxy resin and alumina is from 2.5 to 4.0) in 0.4 MPa SF6,as well as the voltage application times were measured,and then the U-t characteristics were compared accordingly.The damages of the discharge process to alumina filled epoxy resin materials were also studied through the flashover traces and the microcosmic structure analysis.The “wormholes” formation in the discharge and its effect in the flashover process were analyzed and discussed.It is found that the withstand voltage of the epoxy resin with certain alumina content decreases exponentially with time,and the long-term withstand voltages is about 20％～30％ lower than the short-term withstand voltage.The epoxy resin sample with mass ratio of 3.5 has the lowest short-term and long-term withstand voltages and most serious carbonizations according to the experimental results.Wormholes are obviously found in the surface flashover path,and the superficial zone wormholes gradually transform into deep layer wormholes,which indicate that the flashover paths shift from creeping-discharge-based to bulk-breakdown-based due to wormholes effect with the increase of alumina content and the critical mass ratio of epoxy resin and alumina is about 3.0～3.5.