同塔双回高压直流线路地面合成电场的计算方法

Calculation of the Total Electric Field at Ground Level for Double-circuit HVDC Overhead Transmission Lines

我国计划在实际工程中采用同塔双回高压直流线路,由于该类线路在世界上无工程应用先例,需要研究其地面合成电场的有效计算方法,以满足工程设计和环境保护需求。考虑极导线对地距离不同和极导线布置方案对每一极导线起晕电压的影响及正负极导线起晕场强的差别等因素,提出一种计算同塔双回高压直流线路地面合成电场的方法。利用同塔双回直流模拟试验线段,对极导线按不同方案布置时的地面合成电场进行测试,并采用该文方法对地面合成电场进行计算。结果表明,采用该文方法计算极导线按不同方案布置时同塔双回直流线路的地面合成电场,其分布规律与实测结果基本吻合;地面最大合成电场计算值与实测结果基本一致。

Double-circuit HVDC overhead transmission lines will be applied to an engineering project in China for the first time. Because this type of fines has never been applied to actual engineering in the world, it is necessary to study the valid calculation method for their total electric field at ground level in order to satisfy the requirements in engineering design and environment protection study. Considering the influence of the different line clearances above ground between two adjacent poles and pole arrangement schemes on the corona onset voltage of each pole, the difference of the corona onset electric fields between the positive and negative poles and some other factors, a calculation method for the total electric field at ground level for this type of lines was presented. Double-circuit DC experimental line sections with different pole arrangement schemes were used to respectively measure their total electric fields at ground level, and the corresponding calculation results can be obtained with this method. Through comparing the calculation results with the measurement, some conclusions are drawn as follows. For the total electric fields at ground level for Double-circuit HVDC overhead transmission lines with different pole arrangement schemes, their distribution laws and maximal calculation values obtained with this method basically agree with the corresponding measurement, and they can be predicted and analyzed by using this method.