Transient Ground Impedance of Small-sized Ground Electrode considering Underground Discharge in Frozen Soil

동결 토양에서 지중방전을 고려한 소규모 전극의 과도접지임피던스 특성

This paper presents the transient impedance in a discharge region when high voltage lightning impulse is applied to small-sized ground electrodes in frozen soil. For a realistic analysis of ionization characteristics near the ground electrode in the soil, ground rod installed outdoors and high voltage impulse voltage generator were used. From the analysis of response voltage and current flowing ground electrode to earth, it was verified that the ionization near the ground electrode contributes to reduction of ground impedance and limits the ground potential rise effectively under high impulse voltage.