特高压输电线工频磁场三维优化模型

电磁环境是建设特高压输电工程中需要深入研究的关键问题之一，提出在特高压输电线磁场计算中考虑线路的分布参数，根据分裂导线参数、相间导线距离、电压等级等确定线路的波阻抗，进而求得线上电流，然后推导出具有弧垂的架空悬链导线下工频磁场三维优化模型。算例分析表明：传统二维模型所计算出的磁场强度偏大；三维优化模型能够反映线路结构参数对磁场强度的影响，具有更高的准确性；相比于正三角常规型线路排列，倒三角紧凑型线路下方磁场强度明显减小。由该模型所得结果可为特高压分裂导线选择、相线排列方式设置、杆塔高度设计提供参考。

Three-dimension Optimization Model for Power Frequency Magnetic Field of UHV Transmission Lines

Electromagnetic environment is one of the key concerns for ultra high voltage (UHV) transmission projects. The calculation of power frequency magnetic fields (PFMF) of the UHV transmission lines is focused in this paper. At first, the distributed parameters of UHV transmission lines are considered when calculating PFMF. The wave impedance of UHV transmission lines is obtained based on the parameters of the bundle conductors, the phase line clearances and the operational voltage. Then, the current in phase conductors is calculated. In view of the characteristics of the overhead catenary with sag, the three-dimension optimization model for calculating PFMF spatial distribution under UHV transmission lines is established. Examples of calculation show that falsely higher PFMF intensity results when traditional two-dimension model are used, but the proposed three-dimension optimization model can accurately reflect the influence of transmission lines configuration parameters on the PFMF, so it is more helpful in calculation. Compared with the triangular normal arrangement scheme, the inverse- triangular compact transmission line arrangement scheme is conducive to reducing the PFMF intensity. The three-dimension optimization model can be used as reference for choosing bundle conductors of UHV transmission line, setting the arrangement for three phase lines, and designing the tower height.