脱冰工况下特高压输电铁塔地线横担受力特征及破坏模式  

Mechanical Characteristics and Destroyed Modes for Cross-arm Supporting Ground Wires of UHV Transmission Tower Under Ice Shedding

作　　者：杨风利 李清华 邵帅 李茂华 朱彬荣 YANG Fengli;LI Qinghua;SHAO Shuai;LI Maohua;ZHU Binrong(China Electric Power Research Institute,Xicheng District,Beijing 100055,China)

机构地区：[1]中国电力科学研究院有限公司,北京市西城区100055

出　　处：《中国电机工程学报》2024年第10期4157-4166,I0035,共11页Proceedings of the CSEE

基　　金：国家电网有限公司科技项目(5108-202218280A-2-222-XG)。

摘　　要：受超设计覆冰及脱冰跳跃动力冲击影响,特高压耐张塔地线横担发生弯折破坏。该文采用ANSYS建立了地线-耐张塔-金具串有限元模型,通过脱冰跳跃工况下的几何非线性动力时程分析,确定了不同覆冰厚度时地线挂点处的纵向不平衡张力、垂直荷载及动力冲击系数。采用梁杆混合单元建立了地线横担精细化有限元模型,将脱冰跳跃荷载峰值施加在挂点位置,分析得到了地线横担杆件应力分布云图,确定了首先发生失稳破坏的杆件位置,端部下平面第二节间主材弯曲应力与轴压应力之比为37.9%,杆端弯矩影响不可忽略。完成了地线30mm覆冰、大号侧整档100%脱冰工况下的地线横担真型试验,揭示了典型杆件在加载过程中的应变发展规律,反演了地线横担的起始破坏位置及失效模式,与有限元仿真结果及现场破坏形态基本吻合。Affected by the severe accreted ice exceeding design values and impact of ice shedding,the cross-arm supporting ground wires of a typical UHV tensioned transmission tower are bent and damaged.The general finite element software ANSYS is used to establish the finite element model of the ground wire-tensioned tower-fitting string system.Through the geometric nonlinear dynamic time-history analysis under ice shedding cases,the longitudinal unbalanced tension,the vertical load acting on the suspension points as well as the corresponding impact factors are determined for different accreted ice thickness.A refined finite element model of the cross-arm supporting ground wires is established by using the beam and truss element,and the peak load of the ice shedding case is applied to the suspension point.Stress contour of the members of the cross-arm is obtained,and the member location firstly occurred buckling failure is determined.The bending stress of the main member at the second segment is 37.9%of the axial compressive stress,and the influence of bending moment cannot be ignored.The full-scale test of the cross-arm supporting ground wires under the conditions of 30 mm accreted ice and 100%ice shedding ratio at the big-number side is completed.The strain variation trends for typical members during loading are revealed.The original failure location and the failure mode are inversed by full-scale test.The experimental failure mode is basically consistent with the finite element simulation results and the field failure mode.

关 键 词：脱冰 有限元仿真 真型试验 应变 不平衡张力 杆端弯矩 

分 类 号：TM752[电气工程—电力系统及自动化]