임펄스전류에 의한 토양의 종류별 절연파괴 특성 분석

Analysis of Various Soil Breakdown Characteristics to Impulse Currents

In this paper, impulse generator used to investigate experimentally breakdown characteristics of soil and ionization characteristics of the same applied voltage in coaxial cylinderical electrodes systems. The breakdown voltage and current form of soil type depends in dry soil, breakdown voltage-time lags characteristics is changed with particle size. In addition, at the same applied voltage, V-I curve, a transient impedance curve were measured for various soil type. As a result, among gravel, sand, silt, loess of 4 kind soils, sand shows the biggest soil ionization radius because the impedance of the soil is reduced and the loop area of sand is much bigger than that of other soil. The results presented in this paper will provide useful information on the improvement of transient performance of a grounding system subjected to lightning impulse current considering the soil ionization.