利用关键构件力学特性的覆冰塔线体系事故预测方法  

Prediction Method for Accidents of Ice Covered Tower-line System Using the Mechanical Feature of Key Components

作　　者：姚陈果[1] 毛峰[1] 许道林[2] 刘孝全 周泽宏 崔玉家 

机构地区：[1]重庆大学输配电装备及系统安全与新技术国家重点实验室,重庆400030 [2]重庆市电力公司基建部,重庆400014

出　　处：《高电压技术》2011年第2期476-483,共8页High Voltage Engineering

基　　金：国家重点基础研究发展计划(973计划)(2009CB724502);重庆市电力公司科技项目(2009渝电科技#47)~~

摘　　要：针对目前我国输电线路覆冰断线倒塔事故预测方法的不足,选取重庆市某500 kV送电线路的典型杆塔为研究对象,建立了＂三塔两线＂形式的塔线体系精细化有限元模型,进行了塔线体系承受覆冰荷载、风荷载多种运行工况下的仿真研究,通过系统研究确定了能最有效反映杆塔运行状态的构件,并详细记录了杆塔关键构件应力值随运行工况参量的变化趋势,通过公式拟合得出严格的数学函数,具体表现为：三层横担鼓型直线杆塔,上、中、下横担主材角钢应力随覆冰厚度的增加呈指数增长,拟合度高达0.986以上,指数范围集中在0.0375~0.0404之间,因杆塔不同部位角钢型号及结构等因素的影响而略有不同;杆塔塔身主材角钢应力与风速呈指数增长,拟合度高达0.99以上,指数范围集中在0.0383~0.0423之间,因覆冰厚度的不同,塔身主材角钢应力曲线构成一组曲线簇,覆冰越厚,应力值相对越大。基于以上结果提出了利用这种特定的数学函数建立数据库,实时查询、比较,给出杆塔运行中的状态,实现覆冰塔线体系事故预测的方法。Transmission lines which have been built and put into operation have different mechanical properties of towers and lines because of their different operating conditions,topography,microclimate and other factors,and these differences would be more prominent under ice condition.When grids were covered by ice in a large area and the power sectors prepared to do ice melting,they could not get data of mechanical properties of ice covered towers and lines exactly and timely,thus the line in the most danger which required immediate ice melting treatment could not get the fastest treatment,and then accidents would occur.To solve this problem,a typical tower in 500kV transmission line in Chongqing was chosen as an object,and an accurate finite element model in three-tower-two-line form was created.Then the tower-line system was simulated in different operation conditions.Thereafter,components of the tower which could reflect the operation conditions most effectively were determined to be targets,the stress values of these components under different conditions were recorded in detail,and rigorous mathematical functions were formed by formula fitting.The results reveal that the stress on tower cross arms increases exponentially with the increase of ice thickness by function fitting,and fitting degrees are above 0.986,exponents range is 0.0375 to 0.0404,exponents are influenced by size of angle beams in different parts of tower,structure factor and other factors;the stress on tower body increases exponentially with the increase of wind speed by function fitting,and fitting degrees are above 0.99,exponents range is 0.0383 to 0.0423.The stress-wind speed curves of tower body are a set of curves,influenced by the ice thickness,the stress value is higher when the ice is thicker.The specific mathematical relationship between the stress of tower and characteristics parameters of operation conditions is the foundation of accident prediction for ice covered transmission tower-line system.Through systematic data processing,a database

关 键 词：覆冰 塔线体系 关键构件 预测方法 有限元模型 荷载 应力分析 

分 类 号：TM753[电气工程—电力系统及自动化]