输电塔线体系覆冰断线的区间可靠性研究

Study on Interval Reliability of Transmission Tower-line System Subjected to Ice-induced Line Breakage

开展了输电塔线体系覆冰断线的区间可靠性研究,将缺少概率统计参数的覆冰密度和厚度处理为区间变量,并考虑冰体密度与厚度之间的负相关性,进一步通过非概率椭球模型来描述其相关性。对某实际输电塔线体系分别进行了基于动力效应和静力效应的断线可靠度对比分析。进一步地,对比研究了基于随机变量模式和区间变量模式的塔线体系可靠度结果。结果表明,基于动力效应和静力效应的体系断线可靠度存在一定差别。采用静力方法确定断线效应低估了杆塔的破坏状况,失效概率的分析结果偏小。

The investigation on the interval reliability of a transmission tower-line system subjected to ice-induced line breakage was conducted.The ice density and thickness without probabilistic statistical parameters were treated as interval variables.The strong negative correlation between ice density and thickness was considered and the correlation was described by a non-probabilistic ellipsoidal model.A real transmission tower-line system was taken as an example to compute the structural reliability based on both dynamic and static line breakage effects.In addition,the structural reliability under random variable mode and interval variable mode was also compared.The made observations indicate that the structural reliability based on both dynamic and static line breakage effects are different to some extents.The structural damages are underestimated if the line breakage effects are computed in line with static effects and the failure probability is also underestimated.