云广直流输电工程接地极线路绝缘水平优化

Optimization of Electrode Line Insulation Level of Yunnan-Guangdong DC Transmission Project

针对在±800 k V云广直流输电工程的调试和运行过程中多次发生直流系统故障引起接地极线路闪络的问题,对不同故障情况下接地极线路上的过电压水平和分布进行了仿真。结果显示,云广直流接地极线路的绝缘水平与换流站中性母线的绝缘水平以及中性母线避雷器的保护水平确实存在不匹配。分析了降低避雷器保护水平和提高接地极线路绝缘水平两种解决方案。对于新建工程,推荐采用提高接地极线路的绝缘水平方案来解决不匹配问题。对于已投运工程,建议调小换流站接地极线路进线段杆塔的招弧角,将闪络控制在一定范围内。

Aiming at the problem of electrode line flashove due to the DC system failure in ~ 800 kV Yunnan-Guangdong HVDC transmission project during its commissioning and operation period, this paper makes simulation and calculation of the overvoltage level and distribution on the electrode line in different fault conditions. The results show that the insulation level of the electrode line of Yun- nan-Guangdong DC transmission project does not match indeed with that of the converter station neutral bus as well as the protection level of the neutral bus arrester. Two solutions are analyzed ： to reduce the protection level of the arrester, or to increase the insulation level of the ground electrode line. It is recommended to optimize the insulation level of the electrode line for new construction projects to solve the mismatch problem, and to decrease the arcing horn of the towers nearby the converter station for the operating project so to control its flashover position.