【摘要】 冲击电流作用下接地体的表面散流分布对接地体的冲击接地电阻有决定作用。分别在均匀土壤(23Ω·m)和水平双层土壤(上层砂土2 180Ω·m,下层土壤23Ω·m)条件下,对不同型式的方框带射线接地体进行了模拟试验,从散流不均匀度和散流分布的角度,分析了土壤电阻率、冲击电流波前时间和峰值的影响,研究了常用改型方法的效果。结果表明,土壤电阻率越低、冲击电流波前时间越短、冲击电流幅值越高,则接地极散流越不均匀;方框带射线型接地体射线的末端散流一般大于首端和中部的散流,水平射线的中部散流比例基本不受冲击电流幅值的影响;在方框带射线型接地体的射线上添加水平分支及垂直分支能起到很好的降阻效果。更多还原

【Abstract】 Impulse current distribution around grounding electrodes play a decisive role to the impulse grounding resistance of the electrodes. Simulation tests of the current distribution with several types of radial box grounding devices are carried out under a uniform soil( 23 Ω·m) and a layer soil( upper sand 2 180 Ω·m,subsoil 23 Ω·m) respectively. From the perspective of current distribution and evenness degree of current distribution,the influence of soil resistivity,the front time of wave and the peak of the impulse current are researched. The common measures used to improve the impulse characteristics are tested. The results showthat the lower the soil resistivity,the smaller the evenness degree of current distribution is,while it is the same to the smaller of the wave front time,or the higher of the impulse current amplitude; the proportion of current flowed into the earth from the end part is higher than that of the start part and the middle part; the proportion of current flowed into the earth from the middle part nearly does not change with the amplitude of impulse current; and a better resistivity reducing effect can be obtained by adding horizontal branches or vertical branches in the radial part of radial box grounding device.更多还原