Dry-out properties of insulating paper in distribution transformers

Dry-out is an essential step to remove moisture from the insulation during the transformer manufacturing process. This paper presents data on the development of a reliable test method to measure the dry-out rate of insulating papers used in distribution transformers. The results show that the dry-out test can be used as an indicator to compare the dry-out rate of different papers during product development. The test results are also verified during transformer dry-out process at a transformer manufacturing plant. Insulating material with faster dry-out performance provides opportunities for the optimization of the dry-out process and better overall quality of the insulation system.