A crosslinkable and crosslinked polymer composition containing a low density polyethylene (LDPE) homopolymer or low density polyethylene (LDPE) copolymer has excellent direct current (DC) electrical properties. The crosslinked polymer composition has an electrical conductivity of 150 fS/m or less, when measured at 70 C. and a 30 kV/mm mean electric field from a non-degassed, 1 mm thick plaque sample of the crosslinked polymer composition when measured according to a direct current (DC) conductivity method. A cable can be surrounded by at least one layer of the polymer composition.

A crosslinkable and crosslinked polymer composition containing a low density polyethylene (LDPE) homopolymer or low density polyethylene (LDPE) copolymer has excellent direct current (DC) electrical properties. The crosslinked polymer composition has an electrical conductivity of 150 fS/m or less, when measured at 70 C. and a 30 kV/mm mean electric field from a non-degassed, 1 mm thick plaque sample of the crosslinked polymer composition when measured according to a direct current (DC) conductivity method. A cable can be surrounded by at least one layer of the polymer composition.

The disclosure describes a method of purifying a self-healing fluid (SHF) comprising a drying oil and dielectric fluid. The method comprises (a) filtering the SHF through an absorbent material; and (b) subsequently filtering the SHF through a micropore filter system.

The disclosure describes a method of purifying a self-healing fluid (SHF) comprising a drying oil and dielectric fluid. The method comprises (a) filtering the SHF through an absorbent material; and (b) subsequently filtering the SHF through a micropore filter system.

An electric cable comprising: a cable core having a radius and comprising an electric conductor and an insulating system; a first metal layer in radially outer position with respect to the cable core; and a semiconductive protecting layer between the cable core and the first metal layer. The insulating system comprises an insulating layer based on a propylene copolymer and the protecting layer is made of non-expanded material and has a thickness of from 0.5% to 3% the radius of the cable core. The cable is apt to safely operate at thermal cycles of from 20 C. to at least 90 C. (for example up to 130 C. or more), with substantially no deformation of the metal layer and of the overall cable structure.

A coaxial cable system includes an electric conductor to conduct electric power in a gas turbine engine. The system also includes a dielectric tape helically wound to contiguously surround the electric conductor and a flexible conduit disposed to surround and contiguously contact the dielectric tape. A dielectric liquid may be impregnated within the dielectric tape, and a flexible protective cover may concentrically disposed to surround the flexible conduit.

A fluid composition comprises a triglyceride, having at least one alpha-branched fatty acid residue, wherein each alpha-branched fatty acid residue comprises at least one saturated or mono-unsaturated alkyl chain having a total number of carbon atoms ranging from 12 to 20, and wherein the triglyceride has at least one of (a) a flash point of at least 185 C., (b) a fire point of at least 230 C., (c) a pour point of 25 C. or lower, or (d) a combination thereof. The fluid composition may be useful, for example, as a dielectric fluid and/or as a heat transfer fluid in transformers and other electrical device applications.

A fluid composition comprises a triglyceride, having at least one alpha-branched fatty acid residue, wherein each alpha-branched fatty acid residue comprises at least one saturated or mono-unsaturated alkyl chain having a total number of carbon atoms ranging from 12 to 20, and wherein the triglyceride has at least one of (a) a flash point of at least 185 C., (b) a fire point of at least 230 C., (c) a pour point of 25 C. or lower, or (d) a combination thereof. The fluid composition may be useful, for example, as a dielectric fluid and/or as a heat transfer fluid in transformers and other electrical device applications.

The present invention relates to an electrical insulation system having a low environmental impact comprising two fundamental elements: a) a gaseous medium formed by one or more highly fluorinated fluoroketones having between 4 and 12 carbons, at least another additional dielectric gas, other than the fluoroketones, with a vapor pressure greater than 500 mbar and less than 15000 mbar at 0 C., such as fluoronitrile (CF.sub.3).sub.2CFCN, for example, and one or more vector gases; and b) a molecular sieve capable of discriminating water molecules from molecules of other gases present in the gaseous medium of the system. The invention also relates to the use of the insulation system and to the medium- or high-voltage electrical switchgear comprising a complete enclosure in which there are arranged live electrical components and an electrical insulation system according to the invention.

The present invention relates to an electrical insulation system having a low environmental impact comprising two fundamental elements: a) a gaseous medium formed by one or more highly fluorinated fluoroketones having between 4 and 12 carbons, at least another additional dielectric gas, other than the fluoroketones, with a vapor pressure greater than 500 mbar and less than 15000 mbar at 0 C., such as fluoronitrile (CF.sub.3).sub.2CFCN, for example, and one or more vector gases; and b) a molecular sieve capable of discriminating water molecules from molecules of other gases present in the gaseous medium of the system. The invention also relates to the use of the insulation system and to the medium- or high-voltage electrical switchgear comprising a complete enclosure in which there are arranged live electrical components and an electrical insulation system according to the invention.