Transient Impedance Characteristics of Deep-driven Ground Rods

초록

Abstract This paper presents the characteristics of potential rise and effective ground impedance of deep-driven ground rods that are used in soil with high resistivity and/or downtownareas. The impulse currents are injected into the test ground rod and theimpulse ground impedances are examined. The deep-driven ground rods under impulse currents showed inductive characteristics, and the effective ground impedance owing to the inductive component are higher than the steady state ground resistance. Both of the ground resistance and the effective ground impedance decrease with increasing the driven-length of ground rods. Also, the effective ground impedance of the deep-driven ground rods is significantly increased in impulse currents with fast rise time.The reduction of the steady state ground resistance is decisive to improve the impulse ground impedance characteristics of grounding systems. The proposed results would be applicable to evaluate the impulsive characteristics in lightning protection grounding systems.