800 kV特高压直流入地电流对埋地钢管道的影响  

Influence of 800 kV UHVDC in earth on buried steel line pipes

作　　者：张良[1] 何沫 张凌帆 Zhang Liang;He Mo;Zhang Lingfan(Institute of Safety,Environmental Protection and Technical Supervision,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610041,China)

机构地区：[1]中国石油西南油气田分公司安全环保与技术监督研究院

出　　处：《天然气工业》2019年第12期134-138,共5页Natural Gas Industry

基　　金：中国石油天然气股份有限公司重大科技专项“西南油气田天然气上产300亿立方米关键技术研究与应用”（编号：2016E-0610）

摘　　要：为了研究特高压直流输电系统在单极大地返回运行时对附近埋地钢制管道造成的影响,以我国西南地区某管道为研究对象,在全管道范围内,应用了包括阴极保护有效性测试、管地电位监测、管中电流监测、管体腐蚀监测等在内的多种阴极保护测试技术,对接地极放电过程中管道腐蚀及阴极保护参数进行了连续测试,进而研究管道受特高压直流入地电流影响的程度及腐蚀防护措施的有效性。研究结果表明:①放电过程中,恒电位仪、排流锌带等腐蚀防护措施对缓解管道腐蚀起到了积极作用,但部分管段依然存在着腐蚀现象;②该地区管道接地极放电对管道全线均造成了干扰影响,电流流入区域管中最大电流为4.84 A,管地电位最大负向偏移为-4 853 mV,最大正向偏移+568 mV,管壁最大腐蚀速率为0.049 mm/a,超过管道设计控制目标;③特高压直流接地极放电对管道造成了较大的影响。结论认为,该项研究成果可以为钢制埋地管道受特高压直流入地电流影响程度的检测评价标准编制提供数据支撑。In this paper, one pipeline in the southwestern China was taken as the research object to study the influence of a UHVDC transmission system in the operation mode of monopole ground return on the buried steel line pipes nearby. A variety of cathodic protection testing technologies, including cathodic protection effectiveness testing, pipe-to-soil potential monitoring, in-pipe current monitoring and pipe corrosion monitoring, were applied along the whole pipeline to continuously test the pipe corrosion and cathodic protection parameters in the discharge process of grounding electrode. Then, the influence degree of the UHVDC in earth on the line pipes and the effectiveness of the corrosion control measures were investigated. And the following research results were obtained. First, in the process of discharge, corrosion protection measures(such as potentiostat and drainage zinc strip) play an active role in mitigating pipe corrosion, but corrosion still happens in some pipeline sections. Second, the discharge of grounding electrode of the line pipes in this area interferes the whole pipeline with the maximum current in the regional pipe 4.84 A, the maximum negative shift of pipe-to-soil potential -4 853 mV, the maximum positive shift +568 mV and the maximum corrosion rate of the pipe wall 0.049 mm/a, which are beyond the control target of the pipeline design. Third, the discharging of UHVDC grounding electrode has a greater impact on line pipes. In conclusion, the research results can provide data support for the compilation of testing and evaluation criteria on the influence degree of UHVDC in earth on buried steel line pipes.

关 键 词：特高压直流输电系统 钢制管道 阴极保护 腐蚀 监测 排流 管地电位 管中电流 

分 类 号：TE988.2[石油与天然气工程—石油机械设备]