水平地面上过电流多股铜导线起火燃烧过程

The Ignition and Combustion Process of Overcurrent Multi-strands Copper Conductor on Horizontal Ground

为研究水平地面上多股铜导线发生过电流故障时的火灾规律,模拟多股铜导线在不同电流值条件下的过电流故障,利用高速影像及视频截帧技术,研究导线线芯发热、熔断、电弧引燃及绝缘层燃烧规律,量化燃烧过程中火焰传播特征,借助红外热像仪分析导线升温过程。结果表明:电流I<130 A时导线不会出现线芯熔断现象,I≥130 A时导线熔断时间越来越短,且导线熔断是绝缘层起火燃烧的必要条件;I≥140 A断路电弧引燃后,火焰由向导线一端蔓延逐渐变化为向两端蔓延,I≥170 A时火焰传播距离为60 cm;火焰平均速率随着电流值的变化无明显规律,170 A时火焰平均速率最大为0.81 m·s^(-1)。研究结果可为调查此类火灾提供一定参考。

In order to study the law of causing fire when the overcurrent multi-strands copper wire on the horizontal ground fails,simulating multiple strands of copper wires in different current value under the condition of over current fault,using high speed image and video section frame technology,research fever,fusing,arc ignition wire line core and insulating combustion rule,quantification of combustion flame propagation characteristics in the process of insulation,the heating process of wire is analyzed by infrared thermal imager.The results show that when I is less than 130 A,the wire core does not fuse,and when I is more than 130 A,the wire fuse only occurs at the breaking arc,and the wire fuse is the necessary condition for insulation fire and combustion.When I is more than 140 A,the flame spreads gradually from one end of the wire to both ends after the arc is ignited.When I is more than 170 A,the flame reaches the maximum spread distance of 60 cm.The average flame rate has no obvious law with the change of current value,and the maximum average flame rate is 0.81 m·s^(-1) at 170 A.The results provide some reference for the future investigation of such fire.