A significant method to characterize the
electrical properties of materials and to
evaluate the condition of the insulating
systems is the dielectric response study which
can be done in the time or frequency domain.
The dielectric response measuring results can
be affected by different parameters like
measuring voltage, temperature, water content
and aging condition of insulating system. In
this work numerous measurements are
presented, thus to understand, how the
dielectric response measurement results can
be affected by the water content and aging
condition of insulating system of high voltage
rotating machines in the time and frequency
domain. Because of the importance of the
dielectric response application as a nondestructive
diagnostic method
the possibilities
and
limitations
of this method
to reflect the
deterioration
processes due to thermal
and
electrical
stress were investigated.
As test
object,
actual stator bars were
used, that were
manufactured
with Epoxy VPI technology