过电流导线引燃周围可燃物特性研究

Study on characteristics of overloaded wires igniting surrounding combustibles

为研究过电流单芯聚氯乙烯铜导线对周围可燃物的引燃特性,选取截面积为2.5,4 mm2的导线,以30 A为间隔分别通过90~180 A和90~300 A的过电流进行实验,测量导线温度变化,捕捉电弧产生过程图像并研究导线与棉布间距分别为0.5,1,2 cm工况下的引燃能力。实验结果表明,导线过载过程分为升温、燃弧和降温3个过程。燃弧过程中,电弧在导线熔断间隙处产生并逐渐向两侧增长直至熄灭,引起导线铜芯发生液化和气化,产生熔珠喷溅和流体火焰现象。高温电弧与熔珠喷溅具有引燃周围可燃物的能力。

In order to study the ignition characteristics of overloaded BV wires to surrounding combustibles, the wires with cross-sectional area of 2.5 and 4 mm2were selected to conduct experiments with overcurrent of 90~180 A and 90~300 A at an interval of 30 A. The temperature change of the wires was measured and the image of arcing and bead splashing were captured. The ignition capacity with the spacing between the wires and cotton cloth of 0.5, 1, 2 cm respectively was studied. The results show that the overload process of wires can be divided into three processes: heating up, arcing and cooling down. In the process of arcing, the arc is generated at the wire gap and gradually grows to both sides until being extinguished, resulting in liquefaction and gasification of wire copper core, molten bead splashing and fluid flame. High temperature arc and bead splashing have the ability to ignite surrounding combustibles.