考虑疲劳折损的架空输电线路风雨荷载失效概率模型

Wind and Rain Loading Failure Probability Model for Overhead Transmission Lines Considering Fatigue Impairment

作为典型的风振敏感结构,架空输电线路极易受强风雨灾害影响导致故障停运。为了研究强风雨天气及设备自身机械强度对线路失效概率的影响,从输电线路设计规范和材料结构性疲劳过程入手,建立了一种考虑疲劳折损的架空输电线路风雨荷载失效概率模型。模型采用非线性退化过程模拟材料疲劳折损,并依据荷载-强度干涉理论进行失效概率计算。算例分析给出了风、雨、疲劳折损三者作用时的线路失效概率情况,并以IEEE-RTS 79系统为例介绍了以本模型结果为基础筛选重要线路、薄弱档号的方法。该模型能量化不同风雨荷载对失效概率的增大作用,同时响应线路日常振动导致的疲劳折损,是一种全新的建模思路,具有较好的应用前景。

As typical w ind-sensitive structures,overhead transmission lines are easily affected by extreme w eather disasters w hich w ill cause failure outage. In order to study the impacts of strong storm and device mechanical strength on the line failure probability,this paper constructs a w ind and rain load failure probability model w ith considering fatigue impairment based on the design code of transmission line and material structural fatigue process. The model adopts a nonlinear process of strength degradation to describe the material fatigue impairment and utilizes the interference theory of load-strength to calculate the failure probability. We demonstrate different circumstances of failure probability under w ind,rain and fatigue impairment,and take IEEE-RTS79 system as example to introduce a screening method for important lines and w eak spans based on this model. The model can not only quantitatively analyze the increase impact of different w ind and rain loads on the failure probability,but also have response to the fatigue impairment caused by daily physical vibration of lines,w hich is a new modeling idea and has a good application prospect.