| Title |
Ionization Behaviors by Types of Soil due to Lightning Impulse Voltages in a Hemishperical Electrode System |
| Authors |
이규선(Lee, Kyu-Sun) ; 박건훈(Park, Geon-Hun) ; 김회구(Kim, Hoe-Gu) ; 이복희(Lee, Bok-Hee) |
| Keywords |
Soil ionization ; Transient ground impedance ; Time-lag to ionization ; Ionization threshold field intensity |
| Abstract |
This paper deals with the characteristics of soil ionization affecting the dynamic performance of grounding systems under lightning impulse voltage. A concentric hemispherical electrode system was employed in order to facilitate the field calculation and analysis of the experimental results. The parameters such as the ionization threshold and breakdown field intensity, the pre-ionization and the post ionization resistances, the time-lag to ionization, the transient impedance, the equivalent ionized radius for various soil media were measured and analyzed. The dynamic characteristics of ionization processes under lightning impulse voltage are strongly dependent on the types of soil and water content. As a result, a soil ionization reduces the ground resistance and there is a little effect of applied impulse polarity on the soil ionization threshold field intensity. Although the ionization threshold field intensity of wet clay with 30% water content is the highest, its ionized zone was found to be the smallest amongst the test samples. |