【作者】 林雪松；

【导师】 严波；

【作者基本信息】 重庆大学 ， 工程力学， 2008， 硕士

【摘要】 近年来,风偏闪络事故频繁发生,对电网的安全运行造成了严重威胁。初步分析表明,现行设计规程中风偏角的计算公式的不足可能是造成风偏事故频发的主要原因之一。因此,研究架空高压输电线路在随机风场中的风偏,并据此对悬垂绝缘子串风偏角的计算公式进行修正,具有极其重要的工程实用价值。本文首先阐述了国内外高压输电线路的风偏以及风荷载数值模拟的研究现状,指出现有研究输电线路风偏响应的时程分析方法存在不足,主要表现在模拟风荷载时没有考虑空间相关性,未深入研究线路中各种参数对线路风偏的影响。讨论了输电线路随机风场的数值模拟方法,利用考虑沿高度变化的Kaimal风速谱和Davenport空间相干函数,实现了输电线路的风场数值模拟。然后运用时程分析方法,利用ABAQUS有限元软件对不同档距和不同高差的特征段线路在不同风速的风场作用下的风偏响应进行时程分析。得到了特征段线路中悬垂绝缘子串下端点的风偏响应时程曲线,并利用统计方法得到在一定保证率下风偏角的统计值。结果表明,考虑脉动风的动态特性,用数值模拟方法得到的悬垂绝缘子下端的风偏角远大于按规程中传统静力学方法计算得到风偏角,这可能是输电线路产生风偏闪络事故的原因之一。为此提出了利用风荷载调整系数对现行风偏角工程计算公式的修正方法。研究了500kV特征段线路在脉动风作用下,不同档距、不同高差和不同高度风荷载调整系数的取值。更多还原

【Abstract】 Flashover accidents caused by windage yaw of suspension insulator strings of high voltage transmission lines frequently happened and threatened electric power system in recent years. Analysis indicates that the shortage of the calculation method of windage yaw of suspension insulator string in the current design code, which may cause flashover accidents, is one of the main reasons. Therefore, studying on high voltage transmission lines under random wind field, and improving the calculation method of windage yaw of suspension insulator string behave important practical significance in engineering.In this thesis, the researches on windage yaw of high voltage transmission lines and numerical simulation of wind field are firstly reviewed. It indicated that the existing time-history analysis method of the windage yaw of overhead transmission lines behaves some shortcoming, in which spatial correlation effect of wind filed and the effects of various parameters, such as wind speed, height difference, length of span, and height of the line over ground, of transmission lines on windage yaw have not be investigated throughout. To overcome this drawback, the method of numerical simulation of wind field is discussed, and based on the Kaimal spectrum of wind speed fluctuation, in which the variation of wind speed with height above ground is taken into account, and the Davenport coherence function, the fluctuating wind field along the typical transmission line section is simulated by means of WAWS. The finite element models of typical 500kV high voltage overhead transmission line section consisting of bundle conductors, insulator strings and spacers is set up by means of ABAQUS/CAE software. To take into account the dynamic and random effect of wind loads, the statistical results of windage yaw of the typical line section under wind loads, obtained from the time histories of windage yaw responses determined by means of ABAQUS software, are compared with those determined by the traditional method, which reflected that former is larger than the later and this is probably one of the most important reasons causing flashover accidents. Based on the numerical results, an adjustment coefficient of wind load, which is in the range of 1.4-1.6, is suggested to be introduced into the traditional calculation formula of windage yaw of suspension insulator string.更多还原