Till now, there are just not enough on-line monitoring
techniques available. Therefore, the role of the on-line
detections should be evaluated properly. It is pertinent
to regard them as a rough measurement for the first-step,
acting as an early indication or alarm of insulation faults.
When symptoms of incipient faults are discovered, the
sequent corresponding off-line measurements should be
performed. If no abnormal indication is found, then
prolonging the maintenance interval would be suggested.
With the above practices, the service availability of
power equipment could be enhanced and the
maintenance cost could be saved greatly.