This chapter is therefore devoted to a discussion of some of the problems
encountered when analysing even relatively simple but practical insulating
systems. Teaching experience has shown that this is a necessary prerequisite
in order to gain a clearer understanding of the behaviour of insulating
materials. However, no attempt will be made here to introduce the basic field
equations, or to treat systematically the numerous methods available for calculating
electrostatic fields as this may be found in many books. Rather,
this chapter is intended to provide some fundamental understanding of the
importance of the interaction between fields and materials involved within an
electrical insulation system by discussing some selected examples.