임펄스전류에 의한 봉형 접지전극의 과도접지저항의 특성

초록

This paper deals with the experimental results of transient ground resistances due to soil ionization occurring when an impulse current was injected to a ground rod to ensure a technique of examining dynamic behavior of grounding systems for lightning protection. Potential rise and injected current flowing through the test ground rod were observed. Transient characteristic parameters were examined by the potential rise – current () curve, conventional ground resistance – current curve, conventional ground resistance – electric field intensity curve, and so on. Also physical parameters such as equivalent radius of grounding electrode and progress range of soil ionization were examined. As a result, when soil ionization occurred the test ground rod, the curves showed a pattern of hysteresis of regression type characterizing both the progressing aspects of soil ionization and deionization phases. The conventional ground resistance was significantly influenced by soil ionization. The greater the increase in impulse current, the larger is the decrease in ground resistance. The equivalent radius of grounding electrode increased with the magnitude of injected current. The results proposed in this paper are expected to be useful to realize high performance grounding systems for lightning protection.

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