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Study on Surge Impedance of Grounding Electrode

接地极浪涌阻抗的研究

基本信息

批准号：
60550199
负责人：
TAKASHIMA Takeshi
金额：
$ 0.7万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60550199/
关键词：
Grounding electrode Grounding impedance 地中電流の作る磁界

项目摘要

Surge impedances of grounding electrodes were studied in numerical calculations and in field measurements.(1) In the numerical calculations, the magnetic field induced by the ground current (current which was injected from the grounding electrode into the ground) was taken into account. It was found that this magnetic field considerably increased the inductance of the vertical electrode, but did not influence the inductance of the horizontal electrode.(2) In the field measurements, surge impedances of actual vertical linear electrodes were measured by the use of a surge-impedance tester (current of 0.4 A, building-up time of 1 <micro> sec). It was found that the grounding impedance of the vertical electrode did not much decrease even if the electrde was much lengthened, while the grounding resistance much decreased then. Namely there was an effective length of the electrode from the viewpoint of grounding impedance. For an example, the effective length of the vertical electrode was about 20 m, when the resistivity of the soil was 158-190 <OHM> m. As to the effective length, there is an effective length also for a horizontal electrode, and the effective length for each electrode's type is defferent when the resistivity of the soil is different.(3) In comparison between the calculated impedances and the measured ones, when the electrode was short (about 2 m), the calculated impedance nearly agreed with the measured one, but, when the electrode was long (10-200 m), the calculated one was much greater than the measured one. The reason for the error was sought and seemed that the effect of the attenuation in the propagation was not taken into account in the calculation. Thus a problem in the future is that an improved method of calculation needs to be proposed, where the attenuation is taken into account.

通过数值计算和现场测量，对接地极的浪涌阻抗进行了研究。(1)在数值计算中，考虑了地电流（从接地电极注入到地面的电流）引起的磁场。结果发现，该磁场大大增加了垂直电极的电感，但不影响水平电极的电感。(2)在现场测量中，通过使用浪涌阻抗测试仪（电流为0.4A，建立时间为1秒）测量实际垂直线性电极的浪涌阻抗<micro>。结果表明，垂直电极的接地阻抗随电极长度的增加而减小，而接地电阻随电极长度的增加而减小。即从接地阻抗的观点来看，存在电极的有效长度。例如，当土壤电阻率为158-190 m时，垂直电极的有效长度约为20 m<OHM>。在有效长度方面，水平电极也有一个有效长度，并且当土壤电阻率不同时，每种电极类型的有效长度也不同。(3)将计算阻抗与实测阻抗进行比较，当电极较短（约2 m）时，计算阻抗与实测阻抗基本一致，而当电极较长（10-200 m）时，计算阻抗远大于实测阻抗。寻找误差的原因，似乎在计算中没有考虑传播中的衰减效应。因此，未来的问题是需要提出一种改进的计算方法，其中考虑到衰减。