Research On Wind-Induced Dynamic Response Of Ice-Covered Transmission Tower-Line Systems In High-Altitude Areas

Ultra-high voltage transmission lines are an important infrastructure for transmitting large-capacity electrical energy over long distances between regions,and bear the important mission of ensuring energy supply and consumption balance.They can effectively solve the problems of high proportion of renewable energy integration and cross-province and crossregion large-scale deployment in China.Currently,with the planning and construction of large-scale clean energy bases in Tibet,Yunnan,Sichuan,and other areas,ultra-high voltage transmission lines are gradually extending to high-altitude areas in the southwest and northwest.Due to the significant differences in environmental factors such as temperature,air pressure,and terrain between high-altitude areas and middle and low-altitude areas,the operating conditions of ultra-high voltage transmission lines in these areas are more severe,and accidents such as overloading due to ice accumulation or uneven ice shedding are more likely to occur.Based on the upstream of Jinsha River-Hubei±800 kV UHV direct current transmission project,this article conducts research on the response laws and collapse damage of the ice-covered transmission tower-line system under wind loads,and the main research contents of this article are as follows:(1)Based on actual engineering,a model of angle steel members for ice-covered transmission towers was established.The influence of ice type and thickness on the structural performance of ice-covered members was studied,and a method for modifying the elastic modulus of ice-covered members was proposed.A refined finite element model of the icecovered transmission tower-line system was established using ABAQUS,and the influence of ice on the dynamic characteristics of the structure was analyzed.(2)The wind load simulation program for high altitude areas was developed,which takes into account environmental factors such as air density and terrain based on historical measured data from meteorological stations.The program was used to analyze and compare the characteristics of wind loads in high and low altitude areas.(3)Based on a refined finite element model of the ice-covered transmission tower-line system,a parameterized analysis was conducted on the uniform ice-covered long cross-arm transmission tower-line system in high-altitude areas under the influence of wind loads.The response characteristics and force performance of the ice-covered tower-line system were studied under different ice thicknesses,wind speeds,and wind attack angles.(4)Considering the effects of the location and rate of ice accretion on power transmission lines as well as ice shedding,an analysis of wind-induced vibration response of power transmission tower-line systems under non-uniform ice was carried out.Based on measured data of ice conditions in high-altitude regions and non-linear hysteresis models,a study on collapse and failure of power transmission lines under actual ice conditions in highaltitude regions was conducted.