大跨越架空输电导线钢芯铝股应力分布特性研究

Stress Distribution Characteristics of Steel Core and Aluminum Strand of Large Span Overhead Transmission Line

准确评估输电导线运行张力的分层特性是大跨越输电导线选型设计的重要问题.以大跨越架空用特强钢芯高强铝合金AACSR-EST500/230型导线为例,考虑股线泊松比影响,提出了大跨越输电导线股线轴向张力计算方法,建立了大跨越输电导线三维结构有限元实体模型,通过耦合同层和相邻层节点模拟各层股线之间的接触边界条件,重点研究了运行张力作用下输电导线钢芯和铝股的空间应力分布规律,并与理论结果对比分析,探讨了导线比载与钢芯铝股张力比的相关关系.结果表明:在轴向张力作用下,钢芯承担了约60%张力,铝股共承担了40%张力,其张力比约为3∶2,且钢芯和铝股的张力从内至外各自呈增大趋势;大跨越输电导线在悬挂点处的铝股应力强度高于跨中,距离悬挂点越近,股线应力受边界约束影响越大;输电导线相邻层股线的轴向应力峰值呈现相位差;随着导线比载的增加,钢芯和铝股的张力比呈增大趋势.

It is important to accuratly evaluate tension distribution of transmission line for type section design of large span overhead transmission line. Taking AACSR-EST500/230 wire for example, the calculation method of axial tension is purposed considering Poisson ratio effect. The three-dimensional finite element model of transmission line is established. Through coupling with layers and the adjacent layer nodes to simu- late contact boundary conditions of each layer strands, the space stress distribution of steel core and aluminum strand under running tension is researched and compared to theoretical analysis. Finally, the correlation be- tween unit-area weight and tension ratio is analyzed. The results show that the steel core bearing tension is a- bout 60% and aluminum strand is 40% ; the tension ratio is about 3 ： 2. The bearing tension of steel and alu- minum strand is increasing from the inside to the outside. The stress intensity of the suspension point is high- er than midspan for large span transmission line. Closer the suspension point is, the greater the stress is af- fected by the boundary constraint. The peak stress of the adjacent layer of the transmission line is in the phase difference, and the stress level of the outer layer is greater than inner. With the increase of the unit-area weight of wire, the tension ratio of the steel core and aluminum wire is increasing.