风速对特高压直流输电线路离子流场分布的影响

Effect of Wind Speed on Ion Flow Field Under UHVDC Transmission Lines

特高压直流(UHVDC)输电线路地面离子流场的大小是检验电磁环境是否超标的重要判据,对不同风速条件下的地面离子流场的分布进行了计算研究。针对离子流场的计算,提出一种改进迭代上流有限元方法,建立了考虑风速影响的离子流场模型。研究了不同风速对±800 k V输电线路离子流场分布规律的影响。研究表明,地面最大合成场强和离子流密度随风速的增大而增加明显,且风速会使其发生一定偏移。考虑风速为8 m/s时,地面最大合成场强比无风增加了12.64 k V/m,且地面最大离子流密度是无风时的2.65倍。水平风速越大地面合成场强和离子流密度的分布曲线和峰值往背风向偏移越严重,空间其他较远处的合成场强和电荷密度变化不大,且空间合成场强与电荷密度的最大值主要分布于导线周围空间。

The size of the ground ion flow field of ultra-high voltage direct current （UHVDC） transmission line is an important criterion to test the electromagnetic environment. An improved upstream finite element method is proposed, which is based on the consideration of the influence of wind speed. The influence of different wind speed on the distribution of ion flow field of ±800 kV transmission line is studied. It is obtained that the maximum ground level electric field strength and ion current density increase with the increase of the wind speed. And the maximum values shift to the downwind side with the effect of wind. Considering the wind speed as 8 m/s, the maximum electric field strength on the ground will increase by 12.64 kV/m and the maximum ion current density is 2.65 times than that with no wind. With the wind speed increasing, the distribution curve and peak value of ground electric field strength and ionic current density shift to the back direction of wind more seriously. The space electric field strength and charge density hardly change in other space. The maximum electric field and space charge density value are mainly distributed in the space around the wire.