Discussion
The above analysis of a simple termination does not include
the effect of field-dependent conductivity, as the purpose is to
demonstrate the effect of the voltage waveform relative to the
dielectric time constant. If the conductivity increases with electric
field, as is usually the case for bulk dielectrics above about
10 kV/mm, the resulting space charge formation tends to make
the resistively graded field more uniform, as seen for the cable
example, above.
The discussion reveals the effect of dielectric time constant
to field distribution during a voltage transition. Capacitively
graded field caused by the voltage change will be superimposed
to the resistive grading unless the transition takes a time much
longer than dielectric time constant. The highest field can be the
resistive grading plus capacitive grading caused by the voltage