
502 Power System Transients
Considering the above equation, Figure 7.28 is drawn from Equations 7.54
and 7.55. The results in the gure agree with measured results in References
26 and 28, and thus, the analytical investigation in this section is conrmed
to be adequate. The characteristic impedance is dependent on the coef-
cient K that is a function of electrode length x, radius r, and buried depth
h. However, K ranges from 6 to 7 for 10 ≤ x ≤ 100 m, 2 ≤ r ≤ 10 mm, and
0.5 ≤ d ≤ 2 m. Therefore, it is clear that K is signicantly dependent on ρ and
f. The propagation constant is not dependent on K.
7.4 . 2 .6 Concluding Remarks
This section deriv ...