Study on Electrical Character of Soil in Impulse Process of Grounding Devices
Cheng Li · Shaanxi Electric Power · 2014
According to the soil constitution,the paper studies the soil electrical model oi porous medium and the frequency dependent characteristic of soil parameters.Based on which the paper points out that the frequency dependent characteristic is of important significance for improving the current divergence efficiency of grounding device and reducing the transient impulse grounding impedance.Moreover,the paper also studies the dynamic physical processes and testing methods of the soil with spark discharge phenomenon in the impulse process of the grounding devices as well as its impact on the grounding device.Finally the experimental study on the spark discharge phenomenon is done.The results show that the initial impulse hreakdown field density of the soil spark discharge will decrease with the increase of soil moisture content;and ahove 0℃,the soil spark discharge phenomenon is more likely to happen if the temperature is higher.