重冰区输电塔-线体系脱冰振动的数值模拟

SIMULATION OF ICE-SHEDDING OF TRANSMISSION TOWER-LINE SYSTEM IN HEAVY ICE REGIONS

重冰区架空线路的脱冰振动可能造成金具损坏、导线断股、杆塔折损等机械事故,也可能造成闪络、烧断导线等电气事故。考虑几何非线性的影响,采用有限元理论建立了输电线路塔-线体系的脱冰振动精细化数值分析模型。以向家坝―上海800kV特高压直流输电线路为例进行了脱冰振动分析,分析了脱冰工况下导(地)线跳跃高度、最大水平张力、绝缘子内力和摆动位移、支座反力等变化规律。结果表明:导线脱冰振动将引起较大的竖向振动,导线最大水平张力增大了近20%,输电塔支座反力增大了约30%。基于上述模型,进行了12种工况下的参数分析,探讨了脱冰程度、绝缘子摆动刚度、阻尼比、不等跨、跨数、风荷载等参数对脱冰振动的影响规律。

The vibration of overhead lines caused by ice-shedding in ice regions may damage metal members and wires stocks, even result in tower collapsed and other machinery accidents. A refined ice-shedding vibration model of transmission tower-line system is established by finite element method considering geometric nonlinearity. Taking the 800 kV transmission line UHV DC from Xiangjiaba to Shanghai as an example, the ice-shedding vibration is analyzed, obtaining the high-jump, the biggest horizontal tension forces, the swing shift of insulator and the restraint forces. The results show that ice-shedding of electrical wire will cause great vertical vibration. The maximum wire tension increases by nearly 20%, and the bearing reaction of power transmission tower increases by about 30%. Using the proposed model, a total of 12 ice-shedding scenarios are studied with variables including ice thickness, insulator swing stiffness, span length, damp ratio, unequal spans, number of spans, wind loads. The influences of those parameters on vibration ice-shedding were analyzed.