Insulation strength of transformers

THIS PAPER is presented to review the work of the transformer subcommittee in setting up standards for the insulation strength of transformers. An effort will be made to present the steps in the development of the insulation co-ordination problem in regard to transformers and to clarify certain points on which misunderstandings have arisen. The present insulation strength standards and tests will be given so that the margin between the protective level and insulation strength as demonstrated by test may be given proper consideration.