Ionization Behaviors by Types of Soil due to Lightning Impulse Voltages in a Hemishperical Electrode System

반구형 전극계에서 뇌임펄스전압에 의한 토양의 종류별 이온화 특성

  • 이규선 (인하대학교 전기공학부) ;
  • 박건훈 (인하대학교 전기공학부) ;
  • 김회구 (인하대학교 전기공학부) ;
  • 이복희 (인하대학교 전기공학부)
  • Published : 2009.01.01

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.

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