The measuring results confirm the sensitivity
of the dielectric response to water content in
the high and low frequency, although the
changes in low frequency are more dominant.
The dielectric losses increase because the
water molecule is polar and the rising water
content of the insulation causes an increase in
the orientation polarization processes, beside
other physical and chemical degradations
which may also lead to an increase of the
polarization and conduction processes. The
dissipation factor in the wet condition exhibits
a local peak, which shifts toward low
frequencies with drying process within the
insulation and finally disappears. The
capacitance or relative permittivity also shows
an increase with water absorption and return
to original values within the drying progress.