特高压直流输电线路外绝缘设计若干问题研究*

绝缘子长度和空气间隙距离的选取是特高压直流输电外绝缘设计的关键技术问题,其中涉及外绝缘试验操作冲击波的选取、导线高幅值直流工作电压对空气间隙放电电压的影响、绝缘子污闪电压与其长度的关系、高海拔影响等实际问题.特高压工程技术（昆明）国家工程实验室对特高压直流输电线路外绝缘设计中的若干问题研究取得了如下结果：给出了操作冲击波头时间长度的建议;验证了复合绝缘子直流污闪电压与其长度的线性关系;提出了可供工程设计用的空气间隙放电电压和绝缘子直流污闪电压的海拔修正系数.

Research on Several Problems in External Insulation Design of UHVDC Transmission Line

The selection of insulator length and air gap length is the key technical problem of UHVDC transmission external insulation. It is related with the practical issues such as the selection of switching impulse waveform in external insulation test, the influence of high magnitude direct current voltage on conductor, the relationship between pollution flashover voltage and insulator length, and the high altitude influence. The research on several problems in external insulation design of UHVDC Transmission line in UHV Engineering Technology (Kunming) National Engineering Labratary has obtained the following achievements:giving the proposal of wave front time length in swithcing impulse voltage test, verifying the linear relationship between insulator DC pollution flashover and its length, and providing altitude factors for air gap and DC polluted composite insulator.