变电站大地网接地阻抗测试研究

Research on the Measurement of Grounding Impedance of Substation Earth Network

关键词:  变电站  大地网  接地阻抗  测试  直线法  夹角法

Key words:  substation  earth network  earth impedance  test  method of straight line  method of included angle

摘要:

本文通过对江门市220 kV杜阮变电站大型地网接地阻抗进行测试，运用电流-电压表（变频/定频）三极法的直线法、30°夹角法、远离夹角法进行实践分析。结果表明：大地网接地阻抗值与测试电流、频率无关，与互感系数、电流极和土壤的接触面积以及电流线和电位线的夹角有关。在测试中，应尽量增大电流极与土壤的接触面积，增大电流线与电位线之间的距离，测试结果接近或小于设计值，相比之下，远距离测试法更符合要求。

Abstract:

In this paper,the grounding impedance of the large-scale grounding grid of 220 kV Duruan substation in Jiangmen City is tested,and the straight line method,30° angle method,and far angle method of current-voltage meter (frequency conversion/fixed frequency) three-pole method are used for practical analysis.The results show that the grounding impedance value of the grounding grid is independent of the test current and frequency,and is related to the mutual inductance coefficient,the contact area between the current pole and the soil,and the angle between the current line and the potential line.In the test,the contact area between the current pole and the soil should be increased as much as possible,and the distance between the current wire and the potential wire should be increased.The test result is close to or less than the design value.In contrast,the long-distance test method is more in line with the requirements.