我国部分地区输电走廊非常紧张，为了提高单位走廊的电能输送能力，可以采用更有效率的输电线路方式，同走廊双回直流线路是一种备选方案，然而双回直流线路同走廊架设在世界上尚无工程应用先例。文中给出了一种同走廊双回直流线路地面合成电场的计算方法，考虑了影响此种线路地面合成电场的多种重要因素，并使用该方法分析了同走廊双回直流线路地面合成电场的分布特点。结果表明：不同的极导线布置方案不会显著影响地面最大合成电场的大小，但会影响其分布位置；同走廊双回直流线路地面最大合成电场的绝对值与单回直流线路的差别不大；同走廊双回直流线路能在一定程度上提高单位走廊的电能输送能力。

In some areas of China the land for transmission corridor is in short supply. To raise the power transmission capability of unit corridor, more efficient arrangement of transmission lines has to be adopted in which the scheme of double-circuit HVDC transmission lines in the same corridor is one of the alternatives. However, it is not reported hitherto on double-circuit HVDC transmission lines arranged in the same corridor as well as the calculation of the total electric field at the ground level underneath them. To meet the demand of engineering design and electromagnetic environment protection under such a condition, it is necessary to study the calculation of the total electric field at ground level underneath the double-circuit HVDC transmission lines utilizing the same corridor. In this paper an approach to calculate the total electric field at the ground level underneath the double-circuit HVDC transmission lines in the same corridor is proposed in which multi important factors impacting the total electric field are taken into account. Using the proposed method, the distribution features of the total electric field at ground level underneath such transmission lines are analyzed. Research results show that different pole arrangement schemes do not evidently impact the magnitude of the maximal total electric field at ground level underneath the double-circuit HVDC transmission lines in the same corridor but the distribution of the total electric field; the difference between the absolute value of the magnitude of the total electric field at ground level underneath the double-circuit HVDC transmission lines and that of the single circuit HVDC transmission line is not evident; by use of the double-circuit HVDC transmission lines in the same corridor, the power transmission capability of unit corridor can be raised to a certain extent.

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