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Developing cracks in the soil by means of explosions in the holes, as is called the explosion grounding electrode in this study, is a very effective way to reduce the grounding resistance in the area with high resistivity soil. In this study, the influence of the grounding grid scale and the arrangement of the grounding electrode on reducing the grounding resistance of three-dimensional grounding grid with explosion grounding electrode are studied. There is a strong shielding effect between the explosion grounding electrodes. When the distance between the explosion grounding poles is short, the effectiveness of reducing the grounding resistance by using the long explosion grounding electrode is obviously restrained. The distance between the explosion grounding electrodes should be more than half the length of the electrodes.

Developing cracks in the soil by means of explosions in the holes, as is called the explosion grounding electrode in this study, is a very effective way to reduce the grounding resistance in the area with high resistivity soil. In this study, the influence of the grounding grid scale and the arrangement of the grounding electrode on reducing the grounding resistance of three-dimensional grounding grid with explosion grounding electrode are studied. There is a strong shielding effect between the explosion grounding electrodes. When the distance between the explosion grounding poles is short, the effectiveness of reducing the grounding resistance by using the long explosion grounding electrode is obviously restrained. The distance between the explosion grounding electrodes should be more than half the length of the electrodes. [ABSTRACT FROM AUTHOR]

The reliability and availability of the electric power transmission system is severely influenced by lightning. In Brazil, roughly 65% of the overhead transmission lines outages are due to lightning, whereas the backflashover is the predominant phenomenon compared to shielding failure. Hence, obtaining a low value for the transmission line grounding impedance is an important issue when dealing with transmission lines backflashover performance. Usually, for high resistivity soils, increasing the grounding grid dimensions does not lead to low impedance due to the effective length issue. In this work, a special arrangement of ground electrodes is proposed in order to overcome the effective length problem in high resistivity soil. The transient voltage response of this low impedance ground arrangement is evaluated numerically using parametric modeling approach. Comparisons of numerical simulations results and measurements from a reduced model study are presented for validation purpose. Additionally, the quality of the results obtained using the reduced model elects it as a valuable tool for studies of electromagnetic transients involving interaction of lightning and grounding grids. [ABSTRACT FROM AUTHOR]