重冰区特高压输电线路脱冰跳跃及塔头设计研究

Research on Ice-shedding and Tower Head Design for UHV Overhead Transmission Lines in Heavy Icing Area

采用非线性导线模型,结合重冰区特高压输电线路实际情况进行计算机建模,应用有限元分析,计算档数、档距、覆冰量、脱冰比、高差、风速等因素与导线脱冰跳跃的关系。同时定性分析了导线脱冰跳跃的影响因素,对工程设计提出建议。计算结果表明,在耐张段内档数不超过5档时,脱冰跳跃高度随档数增加而增大;在档距小于1000 m时,档距越大,脱冰跳跃越严重;覆冰量越多,脱冰跳跃越严重;高差越大,垂直脱冰跳跃高度越小;风速越大,脱冰跳跃水平位移值越大。通过对计算结果的分析,对塔头设计时导(地)线层间距、水平偏移值的确定给予建议。

Nonlinear model of conductor is adopted in this article, together with the actual situation of UHV overhead transmission lines in heavy icing area, to conduct computer modeling. Finite element analysis is used to calculate the relationship of the span number, span length, ice thickness, iceshedding ratio, height difference, wind speed and other factors with ice-shedding of conductor. Qualitative analysis is made on the influence factors of ice-shedding of conductor. Proposals are given for engineering design. Calculation results show that the ice-shedding height increases with the increase of span number that is smaller than 5 in the tension section; the longer the span length is, the more serious is the ice-shedding when the span length is smaller than 1000 m; the larger the height difference is, the smaller is the vertical jump height of a transmission line after ice-shedding; the horizontal displacement of ice-shedding is larger as the wind speed increases. Based on the calculation results, suggestions are provided for determining the layer distance between conductors and ground wire and the horizontal displacement in tower head design.