直流接地极对附近输电线路杆塔的腐蚀影响及防护措施的研究  

Research on the Corrosion Influence of the HVDC Earth Electrode on the Nearby Transmission Line Towers and the Towers' Protective Measures

作　　者：朱轲[1] 吴驰[1] 扬威[2] 

机构地区：[1]四川电力科学研究院高电压技术所,成都610031 [2]河南电力试验研究院,郑州450052

出　　处：《高压电器》2011年第10期41-47,共7页High Voltage Apparatus

摘　　要：直流电流在大地中流散时,大地将呈现一定的电位分布,当直流接地极址靠近输电走廊时,将有直流通过地线在处于不同等电位面的杆塔之间流动,从而造成杆塔接地体及基础导体的腐蚀。笔者针对锦屏-苏南±800 kV特高压直流输电工程送端龙恩接地极址,以距极址最近的二自Ⅱ回500 kV交流线路为例,将直流接地极、土壤结构、避雷线和杆塔接地体在CDEGS(电流分布、电磁场分析、接地与土壤结构分析)软件中进行数值建模,仿真计算了流过各个杆塔的直流电流值并分析了土壤结构、杆塔接地电阻等参数对直流分布的影响;根据直流接地极设计的总运行年数及各杆塔入地电流值的计算结果,计算了在直流接地极分别以80%、60%、50%阳极运行条件下临近整条交流线路及其每基杆塔的腐蚀量。计算结果表明:中层电阻率越大、杆塔接地电阻越小,流过杆塔的直流电流值就越大,腐蚀就越严重,而整条线路由直流引起的腐蚀量不会超过594 kg;结合计算结果,最后提出了避雷线与杆塔绝缘、填充焦炭等防护措施。When DC current flows through the earth,there will be potential difference among different positions of the ground.If the DC earth electrode site near the transmission corridor,the DC current will flow among the towers with different equipotential surfaces through the shielding wires,which would lead to the corrosion of the towers＇ earth electrode.Actual parameters of DC earth electrode in the Jinping-Sunan ±800 kV UHVDC Transmission Project and the nearest AC transmission line（Er Zi Ⅱ line） under construction are exmplified here,the electrical model of the DC earth electrode,transmission line,ground wire tower grounding body and corresponding soil model are built under CDEGS program in this paper.The DC current flowing through each tower and its distribution character are fully and systematically researched.According to the earth electrode design as the operation total number of years and the calculation result of current value from tower into the ground,under ratio of anode operation,the corrosion quantity of each tower and the total corrosion quantity of the transmission are obtained.Some conclutions can be gotten from the calcultion results： the erossion quantity will be more with the increase of the resistivity of the middle earth layer and decrease of the grounding resistance of the tower,and the total corridor quantity is not more than 594 kg.In the end,some protective measures for the towers are given such as insulation between shielding wires and tower,filling grounding conductor with coke.

关 键 词：直流接地极 土壤结构 直流分布 CDEGS 腐蚀 焦炭 

分 类 号：TM862[电气工程—高电压与绝缘技术]