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US 11,769,608 B2Granted
MFC in pressboards for HV devices
AssigneeHitachi Energy Switzerland AG
InventorsOlof Hjortstam, Fredrik Sahlen, Elson Montibon, Anders Eriksson, Erik Keil
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Abstract
A pressboard for high-voltage devices is disclosed. The pressboard has a density of 0.6-1.3 g/cm3 according to IEC60641-2, and includes 1-15% microfibrillated cellulose (MFC) based on the total dry weight of the pressboard. The pressboard also includes an insulation element. For example, the pressboard is impregnated with an electrically insulating compound. The insulation element may be used in a high-voltage device, such as a power transformer.
Claims19
An insulation element comprising a pressboard for high-voltage devices, the pressboard
- having a density of 0.6-1.3 g/cm3,
- comprising 1-15% microfibrillated cellulose (MFC) based on a total dry weight of the pressboard, and
- having a thickness of 0.8-10 millimeters (mm),
- wherein the MFC is homogenously distributed in the pressboard,
- wherein the pressboard is impregnated with an electrically insulating compound, and
- wherein a ratio of a permittivity of the pressboard in mineral oil and a permittivity of the mineral oil is within a range of
- and/or
- a ratio of a permittivity of the pressboard in ester oil and a permittivity of the ester oil is within a range of 1-1.35.
5 more elements
Dependencies are inferred from the claim text.