金属管道受入地电流影响的抑制措施研究

Research on Repressive Measures of the Influence of the Ground Return Current on the Metallic Pipeline

直流输电系统处于单极大地回线运行方式时,直流接地极入地电流会导致管道上产生感应电位,在管道的破损点会有电流流进、流出,从而加速管道的腐蚀。从耦合途径、敏感设备两个角度,研究了抑制直流接地极入地电流对埋地金属管道影响的措施。分析了直流接地极与埋地金属管道防护距离对管道干扰电压的影响,研究表明当直流接地极与埋地金属管道防护距离大于一定值时,直流接地极入地电流对管道的影响很小,可以不考虑其影响。着重研究了土壤电阻率对防护距离的影响,发现防护距离受土壤电阻率的影响很大,在一定范围内,防护距离随土壤电阻率增大而增大。对分段绝缘法、旁路排流法、强制阴极电流法三种金属管道自身抑制直流接地极干扰的措施进行了总结。

Under mono-pole ground return operation mode of HVDC systems,the enormous ground return current leads to induction potential on the metallic pipeline,and the current flowing into and out of dilapidating point of the pipeline accelerates the corrosion of pipeline. In this article,repressive measures of the influence of the enormous ground return current on the metallic pipeline are studied from two perspectives of the coupling path and sensitive device. The influence of the shielding distance between the DC transmission earthing electrode and the pipeline on induction potential of the pipeline is analyzed. When the shielding distance is greater than a certain value,the influence of the enormous ground return current on the pipeline can be neglected. The effect of the soil resistivity on the shielding distance is emphatically studied. The soil resistivity is found to have a great influence on the shielding distance and the shielding distance increases with the soil resistivity within certain limits. Repressive measures of electromagnetic interference on the pipeline are summarized,including sectional insulation pipeline,bypass discharge,and impressed current cathodic protection.