介绍了扩径导线在国内特高压交流输电线路工程中的应用情况，并依托1 000 kV锡盟—南京特高压交流输电线路工程，在电气特性、机械特性和经济性等方面对常规导线和扩径导线进行了比较。通过比较分析可知，对于特高压交流输电线路工程，在满足输送容量的前提下，采用扩径导线既可以满足电磁环境的要求，又可以有效降低工程投资，对建设“环境友好型、资源节约型”的特高压交流输电线路具有现实意义。

The application situations of diameter-extended conductor for UHVAC transmission line projects were presented. Based on 1 000 kV Ximeng-Nanjing UHVAC transmission line project, the electrical characteristics, mechanical performances and the economic features of diameter-extended conductor and conventional conductors were compared. The results show that the diameter-extended conductor not only meets the electromagnetic environment requirements, but also can effectively reduce the project investment for UHVAC transmission line projects, under the precondition of satisfying the transmission capacity, which has great practical significance for the construction of environmentally friendly and resource-saving UHVAC transmission lines.