What are the methods testing oil?
For in-service equipment in particular, there are many test techniques for evaluating the condition of the insulating
oil. If the technique of dissolved gas analysis is excluded, oil tests can be divided into two basic groups.
The first group includes tests that are concerned with the immediate condition and acceptability of the insulation
in an item of electrical equipment. This group includes dielectric breakdown voltage testing as well as moisture
measurement by the Karl Fischer (KF) method, and determination of insulation condition by measuring the dielectric
dissipation factor.