基于有限元法的耐张线夹钢锚工艺缺陷影响分析

输电网络中耐张线夹普遍存在断裂或脱落现象,严重影响电力系统的安全稳定运行,为探究耐张线夹钢锚凹槽工艺缺陷对线夹整体使用性能的影响,采用有限元仿真的方法对钢锚整体应力分布进行了分析。首先以220 kV输电线路所使用的NY-640/45型耐张线夹为研究对象,根据钢锚与铝管压接状况构成的边界条件建立了三维有限元模型;继而应用Calculix有限元解算工具对模型进行力学仿真分析,同时对比分析了不同凹槽深度对钢锚整体应力分布的影响。仿真结果表明:凹槽深度不一致将破坏钢锚结构对称性,靠近钢锚与导线钢芯压接段的第三凹槽是影响整体应力分布的最大因素,当凹槽深度偏差达0.6 mm时,最大Von Mises应力值和剪切应力比正常情况下分别超出8.6%和降低4.7%;Von Mises应力增加会加速金属疲劳,增加钢锚断裂风险;同时,线夹剪切应力过小将导致铝管与钢锚咬合作用下降,增加耐张线夹脱落风险。

Influence of Process Defects of Tension Clamp Steel Anchors Based on Finite Element Method

Ubiquitous breakage or dropping of the tension clamps in the power transmission grids seriously affect safe and stable operation of the power system. To explore the effect of process defects of the steel anchor groove on the overall performance of the clamps, this paper uses the finite element simulation method to analyze the overall stress distribution of the steel anchor. The paper firstly takes the NY-640/45-type tension clamp used for the 220 kV overhead transmission line as the research object, and establishes a three-dimensional finite element model according to the boundary conditions of the steel anchor and the aluminum tube crimping condition. Afterwards, it uses the Calculix, an open source FEM solver, to perform mechanical simulation for the model, and analyzes the influence of different groove depths on the overall stress distribution of the steel anchor. The results of simulation show that the inconsistent groove depth will destroy the symmetry of the steel anchor structure, and the third groove, which is near the steel anchor and the wire core crimping section, has the most influence on stress distribution. When the groove depth deviation reaches 0.6 mm, the maximum Von Mises stress value exceeds 8.6% and and the sheer stress is 4.7% lower than normal respectively. The increase of von Mises stress will accelerate metal fatigue and increases the risk of steel anchor fracture. At the same time, the decrease of shear stress of the clamp will weaken the occluding relation between aluminum tube and steel anchor, and increase the risk of the tension clamp falling off.