Hitachi Energy Ltd

Hitachi Energy Switzerland Ag

Anders Eriksson

Olof Hjortstam

Fredrik Sahlen

Alejandra Ravanal

Erik Keil

Elson Montibon

Christos Athanasopoulos

A wall bushing for high voltage application is presented. The wall bushing includes a grounded shield. The grounded shield includes a grading ring in a distal end thereof. The grading ring has an elliptic cross section with conjugate diameters, wherein a major diameter of the conjugate diameters is arranged in an axial direction of the grounded shield and a minor diameter of the conjugate diameters is arranged in a radial direction of the grounded shield. The major diameter is larger than the minor diameter.

Wall bushing

A pressboard for high-voltage devices is disclosed. The pressboard has a density of 0.6-1.3 g/cmaccording 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.

MFC in pressboards for HV devices

Growing community of inventors

Ludvika, Sweden

Anders Eriksson