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eng Mineral insulating oils in service
Pahlavanpour, Behrooz; Wiklund, Per
Transformers Magazine Vol. 2, No. 2, 2015
There is precious little basic information openly available on how insulating materials in transformers behave over longer periods of time. However, such information is very important for ensuring that aging equipment works adequately. It is valuable both from the perspective of transformer maintenance/asset management, and as background information necessary for making informed choices on which type of insulating liquid to employ in new equipment.
Hrčak ID: 182788


eng Tap-changer know-how: Hermetical sealing of transformers and tap-changers
Frotscher, Rainer
Transformers Magazine Vol. 4, No. 1, 2017
Oil-filled electrical apparatus must be able to handle a certain thermal expansion of the oil, which is caused by varying oil temperatures due to load changes and/or fluctuations in ambient temperature. This article provides an overview of sealing methods for transformers and tap-changers, discussing also appropriate tap-changer protection techniques.
Hrčak ID: 172546


eng Application of passivators in transformer insulating mineral oils
Lewand, Lance
Transformers Magazine Vol. 2, No. 2, 2015
Electrical insulating mineral oils are mainly manufactured from naphthenic crude sources, with a small number being produced from paraffinic crudes and gas-to-liquids technology. The resulting products are most frequently free of additives, except for certain types of phenol-based oxidation inhibitors, and of a very low percentage by weight, only up to 0.4 %. The main specifications for electrical insulating oils, Doble TOPS, ASTM D3487 and IEC 60296, only allow oxidation inhibitors and any other additives must be agreed upon by the entities in...
Hrčak ID: 182787