Choosing the Right UHV DC Transmission Line Conductor In the UHV DC transmission project, the selection of the line conductor type must not only meet the requirements of long-distance safe transmission of electric energy, but also meet the requirements of environmental protection. Among them, the requirements of line electromagnetic environment limit become the most important factor in wire selection. At the same time, from an economic point of view, the choice of line conductor type is also directly related to the construction investment and operation cost.

      Therefore, in addition to meeting the requirements of economic current density and long-term allowable current carrying capacity, the research on the cross-section and split type of UHV DC conductors should also take into account the electromagnetic environment limits, construction investment and operating losses. Methods, calculation studies of conductor surface field strength and corona inception voltage at different altitudes, and analysis of electric field strength, ion current density, audible noise and radio interference, so as to determine the final conductor split pattern and sub conductor cross section. For ±800kV UHV DC projects, in order to meet the requirements of environmental impact limit, especially the requirements of audible noise, a wire structure of 6×720 square millimeters and above should be used.