中文摘要：

为使输电设施在全寿命周期内获得良好经济效益,对已建成的特高压交流和高压直流工程进行了技术经济分析。从最基本的建设投资和运行损耗分析入手,重点考虑输电系统的线路损耗小时、上网电价、线路工程造价等因素,得到了长期重载的直流输电系统和通常轻载的特高压交流系统其导线的经济电流密度水平,并计算了输电线路导线的总截面积。结合技术经济性分析,提出对于长期重载直流输电系统,输电导线经济电流密度应在0.5～0.6A/mm2水平,而对于通常轻载的特高压交流系统,输电导线经济电流密度应在1.9A/mm2水平;因此特高压直流输电工程应研发使用更大截面的导线,特高压交流输电线路应研究采用扩径比达2倍以上的新型扩径导线,以降低整个系统运行损耗率。

英文摘要：

For the economic benefits of power transmission facilities during their whole life circle,we analyzed the technical and economic aspects of ultra-high voltage AC（UHVAC） and high voltage DC（HVDC） projects that have been put into operation.Based on the construction investment and operation losses,and taking several major factors into consideration,such as the line loss hours of the power transmission system,the on-grid price,the cost of the transmission line project,and so on,we calculated the economical current density levels of the lines which were used in a HVDC transmission system with long-term heavy load or in a UHVAC system with commonly light load,then the total conductor section area of the transmission lines.With further technical and economic analysis,we proposed that the economical current density levels of lines in the HVDC transmission system with long-term heavy load or in the UHVAC system with commonly light load should be around 0.5~0.6 A/mm2 and 1.9 A/mm2,respectively.Therefore,it is concluded that in order to decrease the operation losses ratio of the total system,conductors with larger cross-section on HVDC transmission projects and new diameter-expanded conductors on UHVAC transmission projects need further development.