The VGB-Standard outlines the processes beginning with the procurement of the mineral oil and ending with the commissioning and first start-up of the transformer, and in this context provides information and recommendations regarding the demands on the quality of mineral oils.

The global market for mineral oil products, including such products used as insulating liquids in transformers, has undergone major changes in recent years. These stem inter alia from changes in the manufacturers' product philosophies and shifts in market shares. Altered production processes, new standards and nascent discussions, for example, on the topic of “corrosive sulphur”, have created growing uncertainty among users.

In addition to this, several German power plant operators have discovered quality defects in the insulating oil fillings of new transformers. For these reasons, the VGB Project Group “Transformers” has decided to prepare a guide on the quality requirements of mineral oils in power transformers.

This VGB Standard applies to oil-filled power transformers irrespective of their size. Since the largest field of application by far encompasses inhibited and uninhibited mineral oils, these products are dealt with exclusively. Alternative insulating liquids, for example silicone-based or natural and synthetic ester liquids, etc., are not the subject of this guide.