Special transformer oil is one of the external impurities (such as moisture, dust, fiber, surfactant etc.) will significantly change the electrical insulating oil invasion ability (such as high voltage drop, dielectric loss factor, higher) which requires the production, transportation and storage should have special measures.
Special two is it was added to the transformer after the surface with a variety of solid insulation materials and other components of the contact, transformer oil components and a variety of solid insulating materials (such as varnish, cardboard, rubber, paint, adhesives, etc.) will also change the compatibility, oil and electrical insulation properties, it is for transformer manufacturers to use in all transformer materials and find out whether the transformer oil is mutual solubility (solubility, oil variation), solid insulating material is clean and dry (trace water in oil and solid insulation material between suction and discharge, dust will affect the voltage resistance and dielectric loss).
Therefore, the management of transformer oil is not only a matter of oil producers, it runs through the entire process of sales and use. Production, transportation, storage, loading and unloading process used containers, tanks, pipelines, pumps and even samplers, sample bottles, etc., must reach three words requirements - "special, dry, net."". For special purposes; dry is dry; clean is clean. According to the "Three Character Classic", huge business losses.
Transformer oil composition is very complex, which is mainly composed of alkanes and cycloalkanes, aromatics, transformer oil and its relative dielectric constant between 2.2-2.4, transformer oil pure dielectric strength is very high, can reach more than 4000kV/cm, but works with the purification of transformer oil, only at 50 ~ 60kV / 2.5mm, this is mainly because there are impurities, moisture, air bubbles mixed inevitably in the manufacturing and operation process, and in the operation of electric field and thermal decomposition of gas and oil, polymer. In high electric field, the decomposition of the gas, and the oil in the water and fiber and other impurities in the electric field, the electric field along the direction, arranged in a "bridge", a leakage channel, in serious cases, lead to "bridge" breakdown, to reduce oil pressure strength. Therefore, the structure of transformer internal insulation should take into account the above factors, take necessary measures to prevent the formation of "small bridge"".