
474 Power System Transients
of the pole height h
1
and the basement length h
2
is about 1:3. A customer house
involves the groundings of home appliances and a telephone line, that are
made up of either copper or a steel rod with a length of about 1 m.
7.3 Modeling for Steady-State and Transient Analysis
7. 3.1 Analytical/Theoretical Model
7.3.1.1 Steady-State
In a steady-state analysis, a grounding impedance is almost always modeled
by the grounding resistance R. There are a number of resistance formulas
proposed in various References 1 through 5. Among these, Sunde’s formulas
are well-known and widely used [3,21]:
1. Single vertical groundin