ZR-BV单芯铜线过电流故障电弧熔痕特征研究

为准确认定电气火灾事故中的过电流故障，模拟在不同电流条件下ZR-BV单芯铜线的过电流故障，通过逐帧分析高速影像研究导线发生过电流故障时的变化过程，使用金相分析技术分类研究过电流导线电弧熔化痕迹的组织特征。结果表明:当I≥4Ie时，导线发生熔断，断路电弧将引燃热分解后的绝缘热解气体，造成火灾的蔓延扩大；过电流导线电弧熔断痕与火烧熔痕的宏观特征较为相似，但喷溅熔痕和发散状熔痕是过电流导线所特有的；枝晶偏析组织是过电流电弧熔断痕的典型组织，且随着电流值的升高，枝晶偏析组织分布范围明显扩大，几乎不再出现等轴状组织。

Study on characteristics of arc melting trace in over current fault of ZR-BV single core copper wire

In order to identify the over current fault in the electrical fire accident accurately,the over current fault of ZR-BV single core copper wire under different current conditions was simulated.Through analyzing the high speed images frame by frame,the change process of wire when occurring the over current fault was studied,and the structural characteristics of arc melting trace for the over current wire were classified and studied by using the metallographic analysis technology.The results showed that when I≥4Ie,the fusing of wire would occur,then the open circuit arc would ignite the insulation after the thermal decomposition,which caused the spread and expand of fire.The macroscopic characteristics of arc melting trace and fire melting trace of the over current wire were similar,but the splash melting trace and divergent melting trace were peculiar to the over current wire.The dendritic segregation structure was the typical structure of over current arc melting trace,and the distribution range of dendritic segregation structure extended obviously with the increase of current,barely with the equiaxed structure.