高土壤电阻率条件下的高压直流输电接地极系统接地电阻限值分析  

Analysis of Ground Resistance Limitation Value of HVDC Electrode System Under High Soil Resistivity Condition

作　　者：夏泠风 周挺 许斌 王刚 XIA Lingfeng;ZHOU Ting;XU Bin;WANG Gang(CPECC Central Southern China Electrical Power Design Institution,Wuhan 430000,China)

机构地区：[1]中国电力工程顾问集团中南电力设计院有限公司,武汉430000

出　　处：《高电压技术》2021年第5期1720-1728,共9页High Voltage Engineering

摘　　要：目前,IEC标准和DL行标均未对接地极的接地电阻提出明确的限值要求,但部分海外工程对接地电阻限值提出了额外要求。当接地极极址土壤电阻率较高时,接地极的接地电阻值也会偏大。因此,调研了国内外大量已建接地极的接地电阻值,存在接地电阻>0.35?并长期稳定运行的案例;通过理论推导和仿真计算,分析了高接地电阻对接地极稳态温升、暂态温升、跨步电位差、接触电位差、损耗、周边变压器直流偏磁等方面的影响;结合巴西美丽山二期特高压直流输电工程里约接地极的设计案例,得出当设计合理时,接地电阻偏高不会影响接地极安全稳定运行的结论;基于不同的接地极设计方案对比可知,不限制接地电阻可以在确保接地极安全稳定运行的同时大幅节省工程投资。At present,IEC standard and DL standard has no specific limitation value on the ground resistance of HVDC electrode system,however,in some oversea projects,this value is limited additionally.When the soil resistivity of electrode site is extremely high,the ground resistance will increase as well.Consequently,we list the ground resistances of plenty of as-built HVDC electrode projects,revealing that some projects can operate normally with ground resistance>0.35?.Through theoretical derivation and simulation calculation,we analyze the effects of high ground resistance on the steady-state temperature rise,transient temperature rise,step potential,touch potential,loss,and DC bias of the surrounding transformer.Based on Belo MonteⅡUHVDC project Terminal Rio electrode design case,the conclusion can be drawn that high ground resistance will not influence the stability operation of electrode with reasonable design.The comparison of different design cases reveals that canceling the limitation of ground resistance can save engineering costs without impairing the safe and stable operation of electrodes.

关 键 词：HVDC 接地极 接地电阻 稳态温升 暂态温升 跨步电位差 

分 类 号：TM862[电气工程—高电压与绝缘技术]