Electric Field Effect Research On Uhvdc Transmission Line

Now China is committed to the development of UHVDC(ultra high voltage direct current) transmission, this helps to achieve nationwide resource allocation optimization and energy optimization of supply, but the electromagnetic environmen problems caused by the electric field effect of transmission line have received wide concerns among the people. Therefore, it has important theoretical and practical significance for the research and analysis of the electric effect around the UHVDC transmission lines. And electric field effects on UHVDC transmission lines include ground nominal electric field, ground electric field strength, the ion current density, the corona phenomenon, audible noise and radio interference.These issues mentioned were studied by emulation charge method and analysed by the example of Shanghai-Xiangjiaba ±800k V UHVDC transmission line, the details were as follows:First of all, based on the electrostatic field theory, the ground electric field, the ground total electric field and the ion current density distribution below the transmission line were calculated and simulated. By changing the transmission line operation mode, the height to the ground, splitting the sub-conductor radius, the cross-sectional area and the electrode distance, and the trend of ground electric field and ion flow density were compared under different parameters. Secondly, the corona problem of UHVDC transmission lines was discussed, the audible noise level and radio interference were calculated by using the formula offered by CISPR and BPA. The results showed that for UHVDC transmission line, split the number of conductors was the main factor to affect the audible noise level and radio interference, and the audible noise was more sensitive to the transmission line parameters. Finally, human body model was built in finite element software ANSYS, and the effect of electric field strength on the human body at different distances from the transmission line were calculated by using APDL(ANSYS Parametric Design Language), which was the secondly program of ANSYS. The results show that the effect of the electric field of UHVDC transmission lines generated on the human body was more than AC field, and the electric field strength of the head in the human body was largest, while it wa still in the safe range.