雷电冲击波形对接地极冲击接地电阻的影响实验研究

Experimental Research on Effect of Lightning Impulse Waveform on the Impulse Grounding Resistance of Grounding Electrode

研究雷电冲击波形对接地极冲击接地电阻的影响,在完善接地极冲击接地电阻研究、统一防雷接地实验标准方面有着十分重要的意义。为此,开展了一系列实验,研究了冲击电压、冲击电流波形以及极性对接地极冲击接地电阻的影响,提取了冲击电压、冲击电流波形下的实验差异,总结了规律并分析了原理。研究结果表明：控制冲击波幅值不变时,随着波前时间的减少或半波时间的增加,接地极冲击接地电阻都会降低;冲击接地电阻在负极性冲击波形下的实验结果要比在正极性冲击波形下的大,且差额最大为10%;冲击波发生器的可控性较差,不能保证输出波形的绝对稳定,而土壤火花放电现象会使得冲击波形的局部差异在响应波的幅值上反映出来,造成标准冲击电压、冲击电流波形控制下的冲击接地电阻存在差异,即幅值相同时,波峰区域的冲击波增大会造成冲击接地电阻降低。这些研究结果可以为解决冲击接地实验中的波形问题提供参考。

It is of extremely vital significance to study the effect of lightning impulse waveform on the electrode＇ grounding resistance, which can perfect the research on impulse grounding resistance of electrode and uniform the lightning protection and grounding test results.Consequently, we carried out a series of experiments to study the influences of the impulse voltage, impulse current waveform and polarity on the grounding resistance. By extracting current and voltage impulse differences, we analyzed the principle. The results show that when the amplitude of the impulse wave is constant, the impulse grounding resistance will decrease with the decreasing of the wave front time or the increasing of the half-wave time. The experimental results of impulse grounding resistance under the action of negative polarity impulse are greater than those under positive polarity, and the difference is 10%. The controllability of the impulse wave generator is poor, and the absolute stability of the output waveform cannot be guaranteed. At the same time, the local differences in impulse waveform can change the response impulse waveform amplitude due to the soil spark discharge phenomenon. This can result in the difference resistance between the standard impulse voltage and current waveform control in impulse grounding. That is, when the amplitude is the same, the increase of impulse wave during the peak area can decrease the impulse grounding resistance. These results can provide references for solving the waveform problems in impulse grounding experiment.