特高压直流输电线路与金属回线共塔塔型研究

Research on Tower Type of UHVDC Transmission Line and Metal Return Line on the Same Tower

针对直流输电系统接地极极址及其路径选择困难这一突出问题,同时为了充分利用已有线路走廊和铁塔,节约走廊资源和工程投资,考虑取消接地极及其线路,采用金属回线与极导线同塔架设的方案。从电气性能、电磁环境以及防雷性能等方面,对±800 kV特高压直流输电线路极导线与金属回线同塔架设的塔型进行分析。结果表明:金属回线的水平线间距离一般由电气间隙控制;不同塔型层间距的控制因素不同,这主要与极导线和金属回线的弧垂匹配特性有关;金属回线与直流线路同塔后,极导线和金属回线的反击跳闸率和绕击跳闸率均低于常规独立架设线路。

To avoid the difficult selection of HVDC system grounding electrode site and the grounding electrode line path,make full use of the existing transmission line corridors and towers,save corridor resources and project investment,the abolition of grounding electrode and grounding electrode line is considered,using UHVDC transmission line and metal return line on the same tower.From the aspects of electrical properties,electromagnetic environment and lightning protection performance,the tower type of ± 800 kV UHVDC transmission line pole conductor and metal return line erected on the same tower is analyzed.The results show that the horizontal distance between two metal return lines are generally controlled by electrical clearance;control factors of different tower’s layer spacing are different,which are related to sag match characteristics of polar conductor and metal return line;the back flashover rate and shielding failure rate are lower than those of the conventional independent lines with DC lines and metal return line on the same tower.