distribution of the applied voltage and the development of
uneven stress at different points within the dielectric.
1) Equipotential lines for Sphere-sphere electrode system:
The distribution of the equipotential lines in the gap between
the surfaces of the sphere-sphere electrode system for both
the symmetrically and asymmetrically applied voltages has
been investigated by CSM and shown in fig. 3. Since
rotational symmetry exists in the electrode system, so the
distribution of the equipotential lines have been shown on a
two dimensional plane for the right hand side of the electrode
axis only. The equipotential lines are drawn at a step of 10%
of the applied voltage. It is obvious from the symmetry of the
electrode shape, size and the applied voltage that the 0%
equipotential line for symmetrically applied voltage should
pass through exactly the center of the axis of the electrodes,
which is true as revealed form fig. 3(a), which proves the
validity of the simulation method. It is also observed from the
figure that the equipotential lines are symmetrically
distributed above and below the horizontal axis. However the
lines are not evenly placed, which indicates that the dielectric
in the gap between the electrodes is not stressed evenly
everywhere. The lines are close to each other near the upper
and lower electrode (the high voltage electrodes), indicating
that the dielectric is stressed more at these points compared to
other points.