沿海及强台风环境下10 kV配网架空绝缘导线的失效机理分析

Failure Mechanism of 10kV Aerial Insulation Line of Overhead Distribution System in Coastal and Typhoon Environment

采用宏观与微观形貌分析、X射线衍射和力学分析等手段,对福建沿海某地区“纳沙”台风中10 kV架空绝缘导线的典型断线案例进行了分析。结果表明,绝缘导线在临近绝缘子绑扎处遭受过雷击,导致绝缘皮烧蚀和导线断股,使其无法承受强台风发生时拉应力和剪切力的综合作用,造成了绝缘导线的断线。此外,沿海地区的强腐蚀环境使绝缘子绑扎处的绝缘层发生电痕性破坏,继而导致线芯进水并严重腐蚀,使得导线的力学性能大幅度下降,增大了断线事故的概率。

The failure mechanism of a 10 kV aerial insulation line of overhead distribution system was investigated by means of macro-and micro-structure observation,energy dispersive spectrum,X-ray diffraction and mechanical performance test etc.,taking a broken and corroded line as a typical example,which situated at the coastal area of Fujian province and experienced a severe harassing of typhoon“Nesat”.It is found that being struck by lightning,the insulation skin ablation and wire breakage did emerge on the line in the vicinity of the insulator binding area,which greatly reduced the mechanical strength of the line,especially when the plastic deformation of the rest part of wires occurred.As a result,the aerial insulation line would break under the combined action of tensile-and shear-force brought out by the strong typhoon“Nesat”.On the other hand,the highly corrosive environment of the coastal area has also led to local damage on the binding area,which subsequently resulted in water intrusion into the cable line,thus induced severe corrosion of the aluminum wires.The corroded wires could result in great reduction of the mechanical strength of the aerial insulation line,therefore,lead to huge potential risks of the line breakage when struck by typhoon.