输电线路脱冰工况下, 地线跳跃引发的张力突变会对悬垂绝缘子系统造成显著冲击。非均匀脱冰不仅会增大地线跳跃高度, 还会引发张力异常, 使悬垂绝缘子系统面临几何干涉和潜在失效风险, 严重威胁输电线路的安全稳定运行, 深入研究脱冰过程对悬垂绝缘子系统的影响机理有利于保障输电线路的安全运行。然而, 目前对不平衡张力作用下的绝缘子系统动力响应机理缺乏深入研究, 相关力学建模及工程评估方法尚不完善。该文采用OpenSeesPy建立典型两档耐张段地线-绝缘子-金具串耦合有限元模型, 系统模拟一档完全脱冰引发的动力响应过程, 并分析了初始张力、覆冰厚度和阻尼比的参数敏感性。仿真结果表明：提高初始张力可有效抑制绝缘子偏转和不平衡张力, 但同时也增大了地线跳跃高度; 覆冰厚度越大, 系统各项响应越剧烈; 阻尼比对地线跳跃高度的抑制作用显著, 而对绝缘子偏转角度的影响有限。进一步结合绝缘子弯曲负荷试验得出的极限指标发现, 部分参数组合下悬垂绝缘子系统存在结构干涉及潜在失效风险。该文研究结果可为特高压输电线路在脱冰冲击条件下的响应规律研究, 挂点结构安全评估和设计优化, 实际工程中耐张段张力配置优化, 绝缘子和金具结构选型等提供参考。

Objective: With the continuous development of ultrahigh-voltage (UHV) power transmission projects, transmission corridors often traverse mountainous regions that are prone to seasonal icing and deicing. Ice shedding on transmission lines, especially nonuniform ice shedding, can cause severe tension imbalances, large vertical jumps of ground wires, and transient dynamic forces acting on suspension insulator-hardware string systems. These effects pose significant threats to structural integrity, including geometric interference, insulator deflection, and potential mechanical failure. Moreover, conventional static-based design approaches often underestimate these dynamic events, as they neglect transient load amplification and complex system interactions.However, the mechanical modeling of suspension systems under such abrupt loading conditions remains underdeveloped, especially in the context of unbalanced tension resulting from nonuniform ice shedding. Methods: To address this issue, this study develops a detailed finite element model of a two-span UHV transmission line segment using the OpenSeesPy platform. This model simulates a coupled system comprising ground wires, suspension insulators, and hardware components, introducing time-dependent ice-shedding loads to reproduce realistic deicing scenarios. The modeling framework accounts for nonlinear cable behavior, interactions among components, and geometric nonlinearity due to large displacements to capture the full dynamic response. Full-span instantaneous ice shedding on the large-span side, recognized as the most critical and unfavorable scenario due to severe transient excitations, is specifically analyzed. To ensure the accuracy of the results, the model was validated against comparable experimental benchmarks prior to extensive parametric simulations. Results: Through dynamic simulations, this study evaluated the responses of the suspension string system under various initial wire tensions, ice thicknesses, and structural damping ratios. Parametric sensitivity analysis revealed that increasing the initial tension increased the axial stiffness, reduced insulator swing and unbalanced horizontal force, but magnified the vertical jump amplitude of the ground wires. Thicker ice significantly amplified the dynamic responses, including larger insulator deflections and increased unbalanced forces. Although greater damping effectively reduced jump heights, it had a limited influence on the maximum deflection angle and tension imbalance of the insulator during the initial impact phase. In addition, two failure criteria based on experimental benchmarks were established: a maximum allowable unbalanced horizontal force (5.98 kN) and a critical insulator deflection angle (10.58°), beyond which geometric interference occurred between components. The simulation results showed that for certain combinations of low initial tension and high ice thickness, these thresholds were exceeded, indicating high failure risk. Response surfaces were constructed to visualize how different parameter combinations approached or surpassed these limits, providing intuitive references for assessing safety margins. Conclusions: This study highlights that current design standards may underestimate the dynamic effects of ice shedding on suspension systems. The findings emphasize the necessity of integrating mechanical interference checks and parametric robustness assessments into the design process for suspension insulator assemblies in UHV systems. The modeling framework and sensitivity results guide for configuring damping, wire tension, and hardware design to mitigate dynamic risks during extreme weather conditions. Overall, this study provides a comprehensive mechanical analysis and failure risk evaluation of UHV transmission line suspension systems under ice-shedding events, offers validated simulation tools, insights into governing parameters, and practical recommendations to improve the resilience of power transmission infrastructure in cold-climate regions.