Electrical insulating oils. I . Characterization and pre-treatment of new transformer oils

It is of fundamental importance that appropriate oil purity be preserved for all applications in electrical equipment. Oil purity can be maintained if good oil handling and testing procedures are provided. Trace contaminants and very small particle contents have recently received more attention because of improved measurement techniques. As delivered, new oils require pre-treatment by the users, but most often this is only drying and filtering, although mixing and additive treatments are also used. Care has to be taken, as problems with the miscibility of the compounds can be experienced.<>