《电力勘测设计》杂志社有限公司

在套用标准设计铁塔模块时，电力结构设计师对耐张塔使用条件存在“以大代小”的片面理解。这种基于长期工程实践形成的直观理解认为，那些为抵抗较高风速和覆冰厚度的杆塔可以在不超过其设计水平档距、垂直档距和转角度数等情况下，一定能替代设计标准较低的杆塔。然而，这种误解导致了对安装工况荷载的估计不足，因为标准设计铁塔并未包络实际工程中的所有使用条件。以典型500kV输电线路中常规四分裂JL/LB20A-500/45、JL/LB20A-720/50铝包钢芯铝绞线的标准设计铁塔模块为例，通过理论定性研究和工程实例的定量分析，深入剖析了安装工况下的张力作用机理及分布规律。研究表明，随着代表档距的增大，降温法安装张力呈现明显递减的趋势；在代表档距不变的前提下，假定最大风速和覆冰工况控制气象条件下的安装张力分别随着设计风速、覆冰厚度的增大而减小；按照较厚覆冰、更大风速条件下规划的标准设计铁塔，运用于轻冰或无冰、低风压区可能会严重低估导地线安装工况张力。由此揭示了标准设计铁塔未能全面覆盖实际工程使用条件的根本原因，提出了针对实际工程中普遍存在的“以大代小”现象的合理化建议，旨在确保导线、地线架设施工过程的安全性，并避免因高估荷载而导致的不必要工程投资增加。

When applying the standard design tower module， the power structure designer has a one-sided understanding of the usage conditions of the strain tower. This intuitive understanding based on long-term engineering practice believes that towers that resist higher wind speed and ice thickness can replace towers with lower design standards without exceeding their design horizontal span， vertical span and number of rotation angles. However， this misunderstanding leads to an underestimation of the load of the installation condition， because the standard design tower does not cover all the conditions of use in the actual project. Taking the standard design tower modules of conventional four-split JL/LB20A-500/45 and JL/LB20A-720/50 aluminum-clad steel-cored aluminum strands in typical 500kV transmission lines as an example， the tension mechanism and distribution law under installation conditions are deeply analyzed through theoretical qualitative research and quantitative analysis of engineering examples. The study reveals that as the representative span increases， the installation tension under the temperature reduction method exhibits a significant decreasing trend. Under a fixed representative span， the assumed installation tensions under maximum wind speed and ice-coating control conditions decrease with increasing design wind speed and ice thickness， respectively. Standard towers designed for thicker ice and higher wind speeds， when applied to low-ice/no-ice or low-wind-pressure regions， may severely underestimate conductor and ground wire installation tensions. This fundamentally explains why standard-designed towers fail to fully cover practical engineering conditions. Rationalized recommendations are proposed to address the widespread "replacing small with large" substitution phenomenon in real-world projects， ensuring the safety of conductor and ground wire installation processes while avoiding unnecessary engineering costs caused by overestimation of loads.