Calculation of Total Electric Field at the Ground Level Under Double-Circuit ±800 kV DC Transmission Lines Arranged on Same Corridor With Upstream FEM Method

To increase power transmission capability of unit corridor, the double-circuit ±800 kV DC transmission lines, one of which is from Xiangjiaba to Shanghai and the other of which is from Jinping to Sunan, are arranged on the same corridor. There is not the precedent of engineering application of such a project in the world, so the ground total electric field under the transmission lines is to be researched to meet the demand from both engineering design and environmental protection. An upper stream finite element method (FEM) based method to calculate the ground total electric field strength under the double-circuit ±800 kV DC transmission lines arranged on the same corridor is proposed and the effectiveness of the proposed calculation method is verified by the test results of the analogue testing line. Both results from calculation and tests show that different arrange schemes of polar conductors of the double circuit DC transmission lines arranged on the same corridor do not evidently influence on the magnitude of ground total electric field strength, however the distribution of the ground total electric field is influenced; there is not obvious difference between the absolute value of the maximum ground total electric field strength of the double circuit transmission lines arranged on the same corridor and that of the single circuit transmission line. Finally, the ground total electric field strengths of the double-circuit ±800 kV DC transmission lines arranged on the same corridor are calculated and analyzed.