The failure samples of lightning strike from a certain area of Fujian coast were analyzed in detail by the macro photography,FTIR,TG and SEM. The stress conditions on the load side of insulator were analyzed using the finite element analysis. It's shown that failure samples mainly show the broken chain and less oxidative aging. The excessive amount of carbon black can make insulated layer untimely failure. The insulator load side exist the biggest stress and deformation. The intrinsic shortcomings of overhead insulated conductor leads mechanical properties to be reduced under the effect of cumulative energy and stresses from the arc current,resulting in a large number of cracks. The key to improve the life of overhead insulated cables is to avoid "weak insulation"of insulation material itself.%通过宏观拍照、傅立叶变换红外光谱(FTIR)、热重(TG)分析和扫描电子显微镜(SEM)等方法详细分析了福建省沿海某区域雷击烧蚀的部分失效样品,使用有限元分析方法分析了绝缘子负荷侧的受力情况.结果表明,失效样品主要表现出断链,氧化老化较少.炭黑量过多会使绝缘层过早失效.绝缘子负荷侧存在最大的应力和应力变形,使得设计上"先天不足"架空绝缘导线在电弧电流产生的堆积热量和应力作用下力学性能降低,产生大量裂纹.绝缘材料本身避免"绝缘薄弱处"是从根本上真正提高架空绝缘导线寿命的关键.
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