云广直流输电工程双12脉波桥不对称运行对过电压的影响分析  

Analysis on the Impact of Double 12-Pulse Bridge Asymmetrical Operation on Overvoltage in Yunnan-Guangdong DC Transmission Project

作　　者：赵晓斌 邱伟 黄莹 黎小林 

机构地区：[1]南方电网科学研究院,广州510080

出　　处：《南方电网技术》2013年第6期53-57,共5页Southern Power System Technology

摘　　要：在楚穗直流工程第4阶段孤岛调试的准备工作中,操作极1高端阀组由定角度控制方式切换为定U dio控制方式完成一段时间后,该极低端阀组的M型避雷器发生过热损坏。通过对现场录波文件的分析,确认高、低压阀组不对称运行时400 kV母线上的24次特征谐波谐振是M型避雷器损坏的直接原因。通过仿真分析明确了在400 kV母线上出现24次谐波的机理,确定换流变压器二次侧对地杂散电容引起24谐波放大,导致过电压的产生。建议在切换定角度控制方式为定U dio控制方式时,高、低压阀组应同时切换,且在双阀组分接头控制逻辑中,高、低压阀组应设置跟随逻辑以确保分接头档位差不超过一档。采取上述措施后,可以有效防止由于双阀组不对称运行引起的过电压。After changing high voltage valves converter transformer tap control mode from Angle-Mode to Udio-Mode in positive pole in a short time, the low voltage valves M-type arrester was damaged for overheating in the same pole during Chuxiong-Suidong HVDC project islanding operation commissioning preparatory work. Based on the analysis of on-site transient fault recorder files, the 24th characteristic harmonic resonance on 400 kV busbar when high voltage and low voltage valves are under asymmetric operation is recognized and considered the direct cause of M-type arrester damage. Through simulation analysis, the mechanism of 24m harmonics appear in the 400 kV bus has been confirmed. Stray capacitance on converter transformer secondary side to ground caused 24~h harmon- ic amplification, resulting in the generation of overvoltage. It is suggested that when the converter transformer tap control mode hart- dover is required, the high voltage and low voltage valves should be switched simultaneously. The tap position of low voltage valves converter transformers should be set to follow that of the high voltage valves, to ensure that tap position difference is less than one. These measures can effectively prevent the over-voltage caused by the high voltage and low voltage valves asymmetry operation.

关 键 词：直流输电 避雷器 过电压 特征谐波 谐振 杂散电容 

分 类 号：TM721.1[电气工程—电力系统及自动化]