
122 Power System Transients
results in comparison with measured results, as well as Wagner’s
and Sargent’s formulas, in the table:
Z
h
r
s
=
60 1ln .−
1.24 Calculate voltage V
t
at the top of the tower in Figure 1.66 for
0 ≤ t < 40 ns, taking λ
01
= λ
10
= 1, and compare with the measured
result shown in Figure 1.57b.
1.25 All the formulas in Section 1.7.2 are an approximation based on
penetration depth. Discuss theoretical problems and engineering
advantages of the formulas. If possible, develop a new formula that
is theoretically better than those in Section 1.7.2.
1.8 Introduction to EMTP
1.8.1 Introduction
1.8.1.1 History of Transient ...