特高压输电线路的大截面导线微风振动特性

摘要

In order to obtain the aeolian vibration property of large cross-sectional conducts JL1X1/G2A-1520/125-481 used for ultra-high voltage (UHV) power transmission,governing equations for aeolian vibration of this type of conduct were constructed.The double amplitude,allowable amplitude,and power dissipation per unit length at 16 equally spaced frequency points in a band of frequencies between 8Hz and 80Hz were calculated,and the dynamic bending strain and stress at the suspension point for each frequency point were determined by the maximum amplitude at the antinode.Study shows that,under the self-damping vibration condition,the double amplitude of the conduct increases first and then decreases with the increase of the frequency,with a maximum value at a frequency of near 20Hz,and the vibration amplitude of the conduct exceeds the allowable value when the vibration frequency ranges from 20 to 40Hz.The power dissipation per unit length increases first and then decreases with the increase of the frequency,and reaches the peak value at a frequency of 40Hz.In the band of frequencies between 20Hz and 40Hz,the dynamic bending strain and stress of the conduct were greater than their allowable values.Compared with the weakest band of frequencies between10Hz and 20Hz of the common cross-sectional conduct,the weakest band of frequencies of large cross-sectional conduct JL1X1/G2A-1520/125-481 is between 20Hz and 40Hz,which should be paid more attention in vibration prevention and damping schemes.%为了掌握用于特高压输电的大截面导线JL1X1/G2A-1520/125-481的微风振动特性,对该型导线建立微风振动控制方程,编程计算了8~80Hz频段中16个等间距频率点处导线的双振幅值、允许振幅、单位功耗等风振特性,并利用波腹处的最大振幅确定了导线悬挂点在各频率点的动弯应变与动弯应力.研究发现:在自阻尼振动情况下,该型号导线双振幅值随频率增加先增加后降低,在20Hz附近达到最大值,当振动频率为20~40Hz时,导线的振动幅值超过其允许幅值;导线的单位功耗随振动频率的增加先增大其后降低,在40Hz附近达到峰值;在20~40Hz频段,导线的动弯应变与动弯应力水平偏高,超出了容许值.与普通截面导线的10~20Hz危险频段相比,大截面导线JL1X1/G2A-1520/125-481的危险频段后移至20~40Hz,此型号导线的防振消振方案应该重点考虑20~40Hz频段.