多跨覆冰导线脱冰振动模型风洞试验研究

覆冰导线脱冰可能造成金具、导线和杆塔等构件受力破坏,也可能会引起导线闪络、烧断等电力事故。设计了1∶50的三跨覆冰导线的缩尺模型,采用熔断集中荷载的方法模拟导线脱冰,共七种工况研究三跨导线中脱冰量、脱冰跨位置、覆冰厚度和风速等参数不同时,导线的冰跳高度、导线张力和绝缘子轴力变化规律。结果表明:边跨脱冰将引起比中间跨脱冰更大的竖向振动,跳跃高度增大了近7%,导线张力也有明显增大;在风荷载作用时,导线脱冰振动会受气动阻尼影响,跳跃高度和振动周期都有所减小,导线张力和悬垂绝缘子的轴力随着风荷载增大而增大。

Wind tunnel model tests for ice-shedding vibration of multi-span icing conductors

Icing conductors’ ice-shedding may lead to damages of end fittings, wires and towers, and even tower collapse and other machinery accidents. A three-span 1:50 scale model tests for icing conductors were conducted to obtain conductor’s ice-jump height, conductor’s tension force and axial force changes of insulators. In tests, ice-shedding loads were simulated with suddenly dropping dead-weights from conductors. Seven ice-shedding cases were studied with different magnitudes of ice-shedding, positions of ice-shedding span, ice thicknesses and wind velocities, etc. The results showed that conductor side-span ice-shedding causes larger vertical vibration than mid-span ice-shedding does, conductor’s jumping height increases by near 7% and conductor’s tension force rises obviously; when there are wind loads, conductor’s ice-shedding vibration is affected by aerodynamic damping, conductor’s jumping height and vibration period become smaller, conductor tension force and insulator axial force increase with increase in wind loads.