Abb Ab

Asea Brown Boveri Ab

Mikael Bergkvist

Anna Kornfeldt

Johan Felix

Per Nordberg

Mats Leijon

Bertil Berggren

Jan Isberg

Hans Bernhoff

Li Ming

Dan Windmar

Christer T&ouml;rnkvist

Anders Sunesson

Mats Ekberg

Thorsten Sch&uuml;tte

A method for manufacture of an electric device having at least one conductor and a porous, fibrous and/or laminated electrically insulating dielectric system comprising a solid electrically insulating part impregnated with a dielectric fluid and a porous, fibrous and/or laminated body for use in an electric device produced with the method. The method comprises the steps of: providing a conductor and a porous, fibrous and/or laminated structure of a solid electrically insulating material associated with each other, pretreating the porous, fibrous and/or laminated body with a gelling additive such that the body comprises the gelling additive which imparts a high viscosity and elasticity to the fluid at conditions for which the device is designed to operate under, impregnating the pretreated body comprising the gelling additive with the dielectric fluid, wherein the gelling additive upon impregnation is brought into contact with the dielectric fluid and the gelling additive, at least in part, is dissolved by the fluid such that following the impregnation the dielectric fluid is gelled.

Method for manufacturing an electric device having an insulation system impregnated with a dielectric fluid

Disclosed is a dielectric gelling composition, exhibiting a thermo-reversible liquid-gel transition at a transition temperature, T , wherein the gel comprises an oil and a combined gelator system having molecules of a polymer compound together with fine dielectric particles with a particle size in the nanomneter, 6 nm, range, preferably a particle size within the range from 0.001 to 1000 nm, the use of this dielectric gelling composition in an electric device comprising one or more conductors, a casing or enclosure and an insulation system comprising the dielectric gelling composition. An electric DC-cable having a conductor and an electrical insulation comprising a solid part with a porous, fibrous and/or laminated structure impregnated with the dielectric gelling composition and a method for production of such DC-cable wherein the combined gelator is prepared prior to impregnation are also disclosed.

DIELECTRIC GELLING COMPOSITION, THE USE OF SUCH DIELECTRIC GELLING COMPOSITION, AN INSULATED ELECTRIC DC-CABLE COMPRISING SUCH GELLING COMPOSITION, AND A METHOD FOR MANUFACTURING AN INSULATED ELECTRIC DC-CABLE COMPRISING SUCH GELLING COMPOSITION

This invention is related to a device and a method in an electric power plant for protection of an object (,) against over-currents from a network (,) or another equipment included in the high voltage plant, the device comprising a switching device (,) in a line (,) between the object and the network/equipment. The line (,) between the object and the network/equipment is connected to an arrangement (,) reducing over-currents towards the object (,), said arrangement (,) being actuatable for over-current reduction with the assistance of an over-current condition detecting arrangement (,) within a time period substantially less than the break-time of the switching device (,).

Device and method relating to protection of an object against over-currents comprising over-current reduction

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Uppsala, Sweden

Mikael Bergkvist