A Method for Thermally Upgrading Insulating Paper Using Alkyl-Naphthalene Oil

Kraft paper is used for insulation in oil-immersed equipment such as transformers. While it has given satisfactory performance on electrical and mechanical properties, thermal degradation occurs due to temperature rise in operation. Examples of these kinds of the Kraft paper are cyanoethylated Kraft paper and amine modified Kraft paper. This report indicates the ability of insulating paper immersed in new synthetic insulating oil, alkyl-naphthalene oil, to withstand somewhat higher temperature than in conventional mineral transformer oil.