基于弧垂测量的综合荷载下导线等值覆冰厚度监测方法

Monitoring Method for Equivalent Icing Thickness of Conductor Under Complex Load Based on Sag Measurement

近年中国电网冰灾事故频发,输电线路覆冰监测对电网冰灾防治工作具有重要意义。弧垂作为导线覆冰后一明显变化量,可用于远程在线覆冰监测。因此,该文根据导线力学分析,建立综合荷载下,基于弧垂、温度测量的输电线路等值覆冰厚度数值计算模型,并以连续档下不同塔线连接类型线路,以及大高差非均匀覆冰线路为对象,提出其标况下状态方程参数计算及覆冰厚度监测方法,并在重庆大学雪峰山野外观测站进行现场试验验证。结果表明:模型理论计算等值覆冰厚度与实测值最大相对误差为11.1%;对于特定导线,其最大弧垂f_(M)随等值覆冰厚度近似呈线性变化;当覆冰监测精度一定时,对最大弧垂f_(M)的测量精度需求随导线几何构型增大近似呈指数型上升,当线路档距大于400 m时,温度测量达±1℃,弧垂测量达±1 dm便可实现等值覆冰厚度增长1 mm的测量精度。

Icing disasters seriously affect power system.The accurate measurement of transmission line’s equivalent icing thickness is of important significance for preventing icing disaster.Conductor’s sag is a notable index which can be used to telemeter the ice-thickness of conductors after icing.Therefore,based on the analysis of conductor’s mechanical properties,with the measurement of conductor’s sag and surface temperature,a computational model of equivalent icing thickness on transmission line under complex load was built.Moreover,different types of conductors under continuous spans and high elevation discrepancy span with uneven distribution icing were taken as objects,and the monitoring process and parameter calculation under standard condition were carried out in this research.To verify the proposed method,a natural icing test of conductor was carried out at the Xuefeng-mountain Natural Icing Test Base of Chongqing University.The experimental results show that the computational model has high accuracy in icing monitoring,and the maximum error of equivalent icing thickness is 11.1%.For a certain conductor,the maximum sag f_(M) varies approximately linearly with the equivalent icing thickness.Under a certain monitoring accuracy,the requirement of f_(M)’s measurement accuracy increases exponentially with the increase of conductor geometry.When the span is above 400 m,the temperature measurement only needs to achieve±1℃,and the sag measurement accuracy achieves±1 dm,then the measurement accuracy of equivalent icing thickness growth can achieve 1 mm.