Research On Electric Field Effect Generated By EHVDC Transmission Lines

With the rapid development of our economy, the electric demands are increased dramatically. The electric resources are mainly distributed in the west part of China, while the electric consumption is mainly in the east. In order to take advantages between the east and the west, the long electric transmission line must be constructed. When the transmission distance is over 800-1000km, the EHVDC have the advantages over the EHVAC, so EHVDC have a broad prospects in our country. On the other hand people began to take great concern the environment impact produced by the EHVDC transmission lines.On the basis of the above background, the electric field distribution under the EHVDC transmission lines are calculated in the paper, the influences of the secondary conductor's radius, the layout and the spacing of the secondary conductors, the height of the conductors and the distance between the positive and the negative conductor are calculated by an analytical method. The calculation results show that the height of the conductor is the main factor, the higher the conductor is, the weaker the electric field will be. The radius of the secondary conductor is the second factor for the unipolar transmission line, the larger the secondary conductor radius is, the higher inception voltage is, the weaker the electric field will be. The distance between the positive and the negative conductor is the second factor for the bipolar transmission lines, the larger the distance is, the stronger the electric field will be. The other factors of the transmission line have minor influences on the electric field. The experience formula on the ground maximum electric field intensity and configurations parameters were deduced, which provide references to environmental assessment and engineering design.In order to compare the electric field magnitude and distribution, the power...