电缆弯折敷设燃烧性能研究

    Research on Combustion Performance of Cable Bending and Installation

    • 摘要: 电缆长距离敷设过程中,弧垂高度变化时会出现电缆需要弯折敷设的现象。为了研究多根电缆在紧密排列且弯折敷设时的燃烧性能,文中以交联聚乙烯绝缘电缆为研究对象,分析弯折敷设电缆燃烧时的火焰温度、火焰蔓延速率和燃烧时间等参数。结果表明,随着敷设根数的增加,火焰峰值温度和火焰蔓延速率逐渐升高,且火焰蔓延速率与电缆弯折角度成正比。试验测得,当敷设电缆根数为5、向下弯折角度为90°时,火灾蔓延速率达到5.4 cm· min-1,是电缆水平敷设时的1.9倍。原因为随着弯折角度的增加,电缆在燃烧时的附壁效应和熔滴流淌效应更为突出,导致未燃电缆受到的热对流和热辐射增加,加快了电缆火灾的蔓延速率。

       

      Abstract: During long-distance installation of cables in power system,changes of sag height can easily lead to cable bending.In order to investigate the combustion performance of multiple cables in close arrangement and bending installation.Taking cross-linked polyethylene insulated cable as the research object,parameters of flame temperature,flame spreading rate and burning time were analysised.Results indicated that as the number of cables laid increased,the peak flame temperature and flame spread rate gradually increased,and flame spread rate was proportional to the cable bending angle.When the number of cables laid was 5,and the downward bending angle was 90°,the fire spread rate reached 5.4 cm·min-1,which was 1.9 times higher than that under horizontal cable conditions.The reason was that as the bending angle increased,the wall attachment effect and droplet flow effect of cables during combustion were more prominent,leading to an increase in thermal convection and radiation effects on the unburned cable section,which improved the spread rate of cable fires.

       

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