kV级特高压输电杆塔结构可靠度研究.doc

1000kV级特高压输电杆塔结构可靠度研究 1000kV 级特高 压输电 杆塔 结构 可 靠度 研究重庆大学博士学位论文学 生姓名 :李茂华 指 导教师 :李正良 教 授 专 业 : 结构工 程 学 科门类 :工 学重庆大学 土木工程学院 二 O 一 二 年 四月Analysis on Reliability of 1000kV UHV AC Transmission Tower A Thesis Submitted to Chongqing University in Partial Fulfillment of the Requirement for the Doctor’s Degree of Engineering By Li Maohua Supervised by Prof. Li Zhengliang Specialty: Structural Engineering College of Civil Engineering of Chongqing University, Chongqing, China Apr. 2012 中文摘要摘 要1000kV 线路相对于 500kV线路,线路输送容量和线路投资提高数倍,对整个电网的安全稳定运行的影响也大幅提高。

杆塔结构作为输电线路的直接支撑结构,其安全可靠性直接关系到整个线路的安全可靠性,应如何选取一个合适的值,是一个值得研究的问题 本文针对这一问题,主要开展了如下研究工作: ① 我国已建的 500kV输电线路可靠度分析 我国 500kV 线路的杆塔设计已积累了丰富的工程设计经验,并已形成了较为系统的杆塔结构设计规程,研究 500kV 输电线路结构可靠度对确定 1000kV 特高压输电杆塔可靠度具有借鉴意义首先按目前国际上通用的可靠度计算方法,对我国不同时期的 500kV 线路杆塔结构方法的可靠度进行了校准,然后调研统计了我国 500kV 线路倒塔的数量,通过 500kV线路杆塔失效的频率推出了其失效概率的大致范围,并由此提出了 1000kV特高压线路的可靠度设置水平的建议 ② 1000kV 级特高压杆塔设计方法及目标可靠度取值建议 搜集了国内外有代表性的杆塔设计标准及杆塔荷载标准,包括 IEC 标准、美国导则、欧洲标准,通过一系列的推导,求出各规范的相当安全系数,通过比较相当安全系数的取值,得出了国内外规范的安全度设置水平的定量比值,在此基础上,提出了我国 1000kV特高压杆塔的设计方法、控制工况、结构的可靠度设置水平,以及结构重要性系数、风荷载重现期等。

③基于矩方法的 1000 kV级特高压输电杆塔体系可靠度分析 采用同时考虑平均风压的随机性和脉动风压的随机过程性及其对结构的随机动力效应的等效随机静风荷载模型,将结构在实际风荷载作用下的可靠度等价于结构在等效随机静风荷载作用下按静力可靠度分析方法确定的可靠度引入等价极值事件,将体系可靠度简化为各个失效模式的串联体系,并提出对应的等价极值变量然后采用点估计法求解等价极值变量的统计矩,并根据统计矩信息运用四阶矩可靠度计算方法求解结构体系的可靠度指标及失效概率针对 1000 kV 级特高压输电杆塔研究表明:矩方法简单、高效,基于随机静风荷载模型将其运用于特高压输电杆塔抗风可靠度分析切实可行,具有重要的理论意义和工程实用价值,可推广应用于实际工程的体系可靠度分析 ④ 1000kV 交流特高压真型塔试验及有限元模拟 I 重庆大学博士学位论文 对 1000kV特高压真型试验塔开展了有限元模拟分析,提出了考虑次应力影响的方法,验证了局部屈服的试验结果,验证了杆塔结构构件可靠度研究结论 最后,在总结全文的基础上,提出了进一步的研究展望关 键词 :特高压输电铁塔,可靠度,随机静风荷载模型,等价极值事件,矩方法II 英文摘要ABSTRACTCompared to the 500 kV circuit, the transmission capacity and investment in 1000 kV circuit will improve several times. But it’s requirement of grid to the safe and stable operation also increase. As transmission circuit directly support structure, safety reliability of pole and tower structure directly related to the safety and reliability of the whole state grid. The safety reliability should be how to select is an issue that is worth studyingThis paper’s mainly research work is as follows: ① Reliability analysis on 500 kV transmission line that China has built About pole and tower structure design for 500 kV circuit, our country has accumulated a wealth of experience in engineering design, and has formed a more systematic pole and tower structure design codes. Researching structure reliability for 500 kV transmission line is significance of reference to the determine structure reliability for the 1000 kV UHV transmission tower. First of all, the reliability of calculation on 500 kV line tower structure of China in different periods is calibrated according to the current internationally accepted calculation of reliability. And through the investigation, this paper statistics the number of 500 kV transmission lines collapsed, through failure frequency of the 500 kV transmission circuit launched its the approximate scope of the failure probability.AndThen the proposal on the setting of reliability level of 1000kV UHV transmission tower is raised② Design method and reliability index of 1000kV UHV The domestic and international representative standards of tower design and load are collected, including IEC standard, the United States guideline and European Union standard. Through a series of derivation, comprehensive reliability coefficient of each standard is found out. By comparing the comprehensive safety coefficient, the conclusion about the quantitative ratio of the reliability level of standards home and abroad is drawn. Based on this, several conclusions are proposed including the design method, load condition and load combination, the setting of reliability level of our country 1000 kV UHV transmission tower structure, structure importance coefficient, return period of wind load, etc③ The reliability analysis of 1000 kV UHV transmission tower system based on the moment methods III 重庆大学博士学位论文 The equivalent static wind load model is used, which considers the randomness of average wind pressure and the random process of pulse wind pressure and the stochastic dynamic effect on structure. The reliability of structure under the actual wind load and the reliability of structure under the equivalent random static wind load which is calculated by the static reliability analysis can be considered to be equivalent. By introducing equivalent extreme-value event, the reliability of structure is simplified as series system of each failure mode and corresponding equivalent extreme variable quantity is proposed. Then, point estimate method is used to solve statistical moment of equivalent extreme variable quantity and according to the statistical moment information four order moment method is used to solve the reliability i。