基于有限元分析的强风环境下引流线断股机理研究

Fracture mechanism of lead wire in strong wind environment based on finite element method

为探索强风环境下的引流线断股机理,建立了超高压输电线路六相引流线的宏观有限元模型和单根LGJ-400/50型钢芯铝绞线的微观有限元模型。首先基于宏观模型研究了引流线在强风环境下大幅度摆动的动力学行为,继而将宏观模型的计算结果导入微观模型,细致分析了单根导线在弯曲变形下的应力分布状况。然后结合有限元计算模拟数据进行试验验证,结果表明,引流线遇7级以上大风时会发生过度弯曲,并在线夹压接根部附近区域产生宏观塑性变形,最终发生疲劳断股。经分析得出强风环境下的引流线断股机理是多频次宏观塑性变形导致的低周疲劳断裂。

In order to explore the causes of frequent fracture accidents in strong wind, two finite element models were established respectively. One was a macro structure of six lead lines and the other was a micro model of a single line with materials of LGJ-400/50 ACSR (aluminum conductor steel reinforced). Firstly, the swing behavior of lines in strong wind was studied according to the macro model. Then, the calculation results were applied to the micro model to analyze the stress distribution of a single wire under a large-angle bending deformation. The simulation results were verified in the latter experiment. It is found that when the lead line meets a Force 7 wind or higher, excessive bending will occur and macroscopic plastic deformation is produced near the root of the clamp joint. Finally, the fatigue fracture begins. It is concluded that the mechanism for fracture of the lead line is a kind of low-cycle fatigue fracture which is caused by multi-frequency macroscopic plastic deformation.