钢芯铝绞线疲劳破坏是一个损伤不断累积、强度逐步下降的过程。导线的疲劳强度随其所受的动载荷和导线振动次数的增加而下降,当导线的剩余强度等于此时的动弯应力时,导线发生疲劳断股。因此,研究导线的剩余强度对导线疲劳断股及导线损伤具有重要意义。本文结合超高压输电导线结构特性及受力特性基于非线性强度退化模型推导出了钢芯铝绞线的疲劳剩余强度模型,并根据国际大电网会议中给出的较为保守的导线S-N曲线计算得出了模型中相关参数。通过对导线疲劳剩余强度模型进行实例分析说明了该模型的可行性。研究表明,导线强度衰减程度与载荷加载次数呈非线性关系,不同载荷下导线强度衰减速度不同,导线强度衰减量与导线振动强度及导线振动时长呈正相关,同一载荷下导线强度衰减速度随着载荷加载次数的增加而变快。

ACSR fatigue failure is the process of injury continuous accumulation and strength gradual decline. The fatigue strength of the ACSR is declining with the number of dynamic load increasing. When the residual strength of the strand is equal to the dynamic bending stress, the ACSR strands are broken. Therefore, the research on residual strength of EHV transmission line has the important significant on fatigue breakdown and injury of ACSR. Based on the non-linear strength degradation model, the structural properties and loading characteristics of EHV transmission lines are considered in order to derive the ACSR residual strength model. And the model parameters are calculated according to the conservative S-N curve of ACSR formulated by CIGRE. The feasibility of the residual strength model is proved through the analysis on different examples. The research shows that the relationship between the degradation degree of conductor strength and loading times is non-linear. The strength decay rates are different with different loadings. The amount of conductor strength attenuation is positively correlated with the intensity of conductor vibration as well as the duration of vibration; with the same load, the decay rate of ACSR strength is increasing with loading times increasing.