某交流特高压线路风偏分析

为研究特高压输电线路的风偏机理,文中以1 000kV南荆Ⅰ线风偏闪络事故为基础,开展故障点的风偏分析。采用规范给定的刚性直棒法进行验算,在风压不均匀系数取0.61和0.75的情况下,计算结果均小于发生事故的阈值。在已有研究基础上确定了分裂导线的阻力系数取值;同时进行了风洞试验,确定了绝缘子串的阻力系数。在Ansys建立导线—绝缘子有限元模型,通过谐波叠加法模拟得到风速时程,在此基础上,进行事故线路导线风偏的动态计算,得到了设计风速下的风偏角大小。结果表明,脉动效应对计算结果的放大作用不可忽略,建议在线路设计和验算过程中应考虑脉动效应,并对风压不均系数进行合理的取值。最后对多个风速下的动态风偏角进行了计算,并用线性拟合的方法推算出了闪络事故发生时的可能风速,由此考虑1 000kV南荆Ⅰ线该次风偏闪络事故可能是由短时局部的强对流天气引起。

Analysis of One UHVAC Transmission Line Windage Yaw

In this paper,with the purpose of studying windage yaw of UHV transmission line,the reason of the faultpoint based on the 1 000kV Nan-Jing line I windage yaw accident is analyzed. Firstly,the rigid rod method is takenwhich given by standard to calculate windage yaw angle with using two different wind pressure non-uniform coeffi-cients which refer to 0.61 and 0.75. Both results were less than the threshold. Based on prior research,the drag coeffi-cient of split conductors is determined and a wind tunnel test is carried out to make certain the reasonable value ofthe drag coefficient of insulator string. Then the wires-insulator strings model is established by Ansys and the wind ve-locity time series are generated by harmony superposition method. According to the Ansys model and wind velocitytime series,the time history analysis of the windage yaw are executed. The result shows that the amplification of pul-sating effect couldn’t be neglected. On the basis of the results above,it is recommended that the pulsating effectshould be taken in consideration during design and checking calculation,as well as the reasonable value of wind pres-sure non-uniform coefficient. Finally,it is analyzed that the windage yaw angles under 5 different wind velocity and the fitted curve is figured out. As a result,the possible reason for this accident could be severe convection weather.