| Title |
Behaviors of Impulse Ground Impedances Associated with the Current Injection Point in a Ground Rod |
| Authors |
Bok-Hee Lee ; Dong-Cheol Jeong ; Su-Bong Lee |
| Keywords |
Grounding ; Grounding electrode ; Ground resistance ; Impulse ground impedance ; Lightning protection ; Impulse current ; Ground potential rise |
| Abstract |
This paper presents the behaviors of transient and effective impulse impedances of a long ground rod associated with the current injection points. The laboratory test for the time domain performance of actual-sized model ground rod subjected to a lightning stroke current has been carried out. The transient ground impedances of long ground rods under impulse currents were higher than the ground resistance. Both of the ground resistance and the effective impulse ground impedance decrease with increasing the length of the ground rods. Also, the effective impulse ground impedances are significantly increased in fast rise time ranges. The reduction of the ground resistance is decisive to improve the impulse impedance characteristics of grounding systems. When the test current is injected at the bottom of ground rod, the oscillating pulses with high frequency are included on the wave front of ground rod potential and the effective impulse impedances are higher than any other cases. |