直流电流引起的两个变电站地网电位差评测方法研究

Research on Evaluation Method of Ground Grid Potential Difference of Two Substations Caused by DC Curren

我国广泛采用直流输电线路作为主干输电线路,但直流输电系统将会造成大地电位改变,并对周边产生直流偏磁危害,直流偏磁现象与地表不等电位有关。通过对接地极电位展开研究,对无法准确测量的两个变电站电位差进行估算;通过搭建直流注入点与变电站模型来推导关于两个变电站电位差的估算公式;利用仿真对误差的来源进行分析,结果与变电站地理位置及土壤结构有关。提出的方法在一般情况下满足误差要求,可适用于估算两个变电站地网电位差。该研究成果可为直流接地极选址提供参考,还可评估交流变电站的直流偏磁水平,为变电站的防偏磁设计提供参考。

DC transmission lines are widely used as the backbone transmission lines in China.However,the DC transmission system will cause changes in the ground potential and cause DC bias damage to the surrounding area.The DC bias phenomenon is related to the unequal potential of the ground surface.In this paper,the potential difference between the two substations that cannot be accurately measured is estimated by studying the potential of the ground electrode.The estimation formula of the potential difference between the two substations is deduced by building the DC injection point and the substation model.The source of error is analyzed by simulation,and the result is related to the geographical location and soil structure of the substation.The method proposed in this paper satisfies the error requirements in general,and can be applied to estimate the potential difference between the two substations.The research results can provide reference for the location of DC grounding electrode,and can also evaluate the DC bias level of AC substation,and provide reference for the anti-bias design of substation.