±1100kV特高压直流输电线路邻近树木时合成电场建模计算与特性研究

Modelling and Characteristic Research of Total Electric Field Around Trees Near ±1100kV UHVDC Transmission Lines

高压直流输电线路下方存在树木的情况十分常见。线路邻近树木时,树木端部可能发生电晕或烧灼现象。为了预防火灾、保护树木,有必要通过仿真计算的方法研究树木周围的直流合成电场,为确定线路与树木的净空距离提供参考依据。对树木的有限元建模方法进行研究,提出典型的树木模型,基于三维上流有限元法计算了直流线路产生的合成电场。在±1100 kV真型试验线路下进行地面合成电场测量实验,对比了计算与测量结果。通过计算,讨论了树木位置、尺寸、数量等因素对树木周围合成电场的影响规律。

The situation that trees are located under HVDC transmission lines is very common in practice.When the HVDC lines are close to the trees,discharge or burn may happen at top of trees.In these cases,growth of trees will be impacted and fire may be caused.Calculation of total electric field around the trees is necessary in determination of clearance between the lines and trees.3 D upstream finite element method（FEM） is applied in calculation of total electric field.Modelling method of trees is studied,and typical shape of trees is proposed.Calculation results are compared with experiments under full-scale ±1100 kV transmission lines.Based on the calculation,influences of position,size and number of trees on total electric field are discussed.