直流接地极入地电流对交流变压器的影响

Influence of DC Current Flowing Through the Earthing Electrode on Transformers in AC Power Grid Caused

为了确定直流接地极入地电流对交流电网中有效接地的变压器运行产生的影响程度,通过采用物探法和电流注入法相结合的方法,或根据接地极实际入地电流在地面产生的电位分布测量结果经反演拟合的方法,建立了能够真实反映大地特性的极址电性模型并仿真计算了流入各变压器直流电流值;在直流工程接地极调试期间,对典型电站有效接地变压器测试获得主变中性点最大直流电流达22 A;分析了直流电流对变压器运行影响的机理及因素后确定流入变压器的直流电流≤2倍的空载电流。研究结果为直流接地极入地电流对变压器影响的评估提供了方法和依据。

The DC current flowing through the grounding electrode into the earth will do bad effect to transformers.Mathematical matrix has been founded in several way which could state reality of the electric characteristic of earth.With the matrix,DC current flowing into transformers has been measured and figured out,which could reach 22A at most in experiment.Analysing the principle and factors of the effect caused by DC current,maximum of DC current which will do little effect to transformers has been set up：as 2 times as the current without working.The fruit has provided methords and standards for appraisal of the influence caused by DC current to transformers.