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eng Fire testing for transformer pit fire protection
Lindström, Johan; Försth, Michael
Transformers Magazine
Vol. 1, No. 3, 2014
Transformer pits are conventionally filled with rocks in order to achieve passive fire safety in the event of an oil leak from the transformer. Other solutions also exist but there is no well defined test method that allows an assessment of the fire performance. In this brief article, such a test is presented together with test results for an alternative system where profile planks are used instead of rocks.
Hrčak ID: 185466
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 Volt-time curves of oil-filled power transformer insulation - Survey of 100 years of research – Part I
Gurin, Vitaly
Transformers Magazine
Vol. 11, No. 1, 2024
One hundred years of data are considered for the electrical strength of power transformer insulation and its dependence on time. Where possible, scatter values of breakdown voltage and partial discharge inception voltage have been extracted from the reference list in order to optimize insulation design and possibly enable future statistical coordination of internal insulation of transformers. This article is intended for young transformer engineers and university faculty teaching undergraduate and postgraduate courses.
Hrčak ID: 313171
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