AA8030型铝合金导线火灾前短路熔化痕迹鉴别技术研究

Testing Method for Identifying Pre-fire Electric Arc Beads of AA8030 Aluminum Alloying Conductors

由于AA8030型铝合金导线中微量元素的加入,其火灾前短路熔化痕迹有典型特征。模拟火灾前相间短路故障发生过程,依据熔化痕迹形状进行分类,从而研究火灾前短路熔化痕迹的孔洞、组织等典型特征。研究表明:该导线发生火灾前相间短路故障,可能形成凹坑痕、凸起痕、圆球痕、尖状痕和平起痕等5类熔化痕迹,短路电弧能量越高,越易形成平起痕;火灾前短路熔化痕迹内部孔洞较多,多为致密的树枝晶,晶粒生长方向性强,应结合熔化痕迹的形状特征对组织内部的孔洞、晶粒进行分析,可为认定AA8030型铝合金导线短路故障引发的火灾提供技术支持。

Pre-fire electricity arc beads on the end of AA8030 aluminum conductors have typical characteristics due to microelement involved in these conductors. According to shape of beads,voids and grain structure of cross-sectional area in beads,a testing method was proposed in this study by shorting two line of these conductors. Its results showed that pre-fire arc beads on the ends of these conductors involved five shapes classifications,such as pit,lug,globe,point and rising surface,and more energy of short circuit arc,more possible rising surface;numerous voids,fine dendritic crystal structure with similar arm directions in arc beads were the typical features for examining pre-fire arc beads of these conductors. This method,however,should consider the effects of the arc bead shape on those typical features. This study could provide technique assistance for determining the occurrence of short circuit on AA8030 aluminum alloying conductors prior to a fire.