Abstract: A non-liquid immersed transformer is provided. The transformer includes a magnetic core and a coil winding forming a plurality of winding turns around the magnetic core and a cooling system. The cooling system includes a heat exchanger, a main feeding pipe and a main return pipe, and a cooling pipe for the flow of a cooling fluid. The cooling pipe extends at least partly along the coil winding between a first point adjacent to an end of the coil winding, and a second point adjacent to the other end of the coil winding. The cooling pipe also includes a plurality of convolutions to extend the path of the cooling fluid between one end of the winding and one of the main feeding pipe and the main return pipe.

Abstract: Dry-type transformers with insulating modules are disclosed. Example insulating modules include dielectric screens and supporting blocks. The supporting blocks support the dielectric screens over windings of the transformer. The dielectric screens have first substantially even portions configured to adapt in spaces defined by corresponding cylindrical barriers arranged between first and second windings of the transformers and second substantially even portions, transversal to the first portions and to the first windings of the transformers and extending outwards from the first portions and beyond the supporting blocks. The dielectric screens partly extend around a winding.

Abstract: Non-liquid immersed transformers and methods of measuring aging degree of the transformers' insulation are disclosed. The transformers comprise a solid insulation inside the conductive coil and one or more floating electrodes in the solid insulation. At least a part of the conductive coil and the one or more floating electrodes may form one or more capacitive elements, respectively. An electrical parameter, e.g. complex permittivity, of the capacitive element is measured and the aging degree is calculated as a function of the electrical parameter measurement.

Abstract: Non-liquid immersed transformers and methods of measuring aging degree of the transformers' insulation are disclosed. The transformers comprise a solid insulation inside the conductive coil and one or more floating electrodes in the solid insulation. At least a part of the conductive coil and the one or more floating electrodes may form one or more capacitive elements, respectively. An electrical parameter, e.g. complex permittivity, of the capacitive element is measured and the aging degree is calculated as a function of the electrical parameter measurement.

Abstract: Dry-type transformers with insulating modules are disclosed. Example insulating modules include dielectric screens and supporting blocks. The supporting blocks support the dielectric screens over windings of the transformer. The dielectric screens have first substantially even portions configured to adapt in spaces defined by corresponding cylindrical barriers arranged between first and second windings of the transformers and second substantially even portions, transversal to the first portions and to the first windings of the transformers and extending outwards from the first portions and beyond the supporting blocks. The dielectric screens partly extend around a winding.

Abstract: A cooling arrangement for a dry-type transformer. The arrangement includes blowing equipment configured to blow a gas flow, and an opening positionable in a clamping structure of the transformer. The opening is configured to allow the gas flow to pass from the blowing equipment towards a winding of the transformer, so that the winding is properly cooled. The opening comprises an electric protecting means for dielectric protection of the clamping structure. A transformer including such cooling arrangement is also disclosed.

Abstract: A transformer may comprise a winding wrapped around a magnetic core, the winding having at least one winding portion extending between the magnetic core and the exterior of the winding in radial direction. The winding may comprise at least a first conductor and at least a second conductor, arranged radially adjacent to each other in each winding portion with the interposition of an insulating layer, wherein the first conductor is arranged radially inwardly with respect to the second conductor for part of each winding portion length, and radially outwardly with respect to the second conductor for another part of each winding portion length.

Abstract: A cooling arrangement for a dry-type transformer. The arrangement includes blowing equipment configured to blow a gas flow, and an opening positionable in a clamping structure of the transformer. The opening is configured to allow the gas flow to pass from the blowing equipment towards a winding of the transformer, so that the winding is properly cooled. The opening comprises an electric protecting means for dielectric protection of the clamping structure. A transformer including such cooling arrangement is also disclosed.

Abstract: A dry-type electrical transformer includes a coil assembly having at least one winding wound into a plurality of concentric turns, at least one cooling sector defined between adjacent concentric turns, spacers positioned inside the cooling sector and spaced from each other to allow a plurality of air ducts each defined between two adjacent spacers, and at least one electrical shield positioned in the cooling sector and arranged to electrically shield the air ducts. At least one electrical shield is positioned in the cooling sector and arranged to electrically shield the air ducts. The electrical shield include a first end edge connected to the turn at the inner side of the cooling sector, a second end edge which is free and electrically insulated from the surrounding parts, and a central portion extending between the first and second end edges and is positioned at the outer side of the spacers.

Abstract: A transformer may comprise a winding wrapped around a magnetic core, the winding having at least one winding portion extending between the magnetic core and the exterior of the winding in radial direction. The winding may comprise at least a first conductor and at least a second conductor, arranged radially adjacent to each other in each winding portion with the interposition of an insulating layer, wherein the first conductor is arranged radially inwardly with respect to the second conductor for part of each winding portion length, and radially outwardly with respect to the second conductor for another part of each winding portion length.

Abstract: A dry-type electrical transformer includes a coil assembly having at least one winding wound into a plurality of concentric turns, at least one cooling sector defined between adjacent concentric turns, spacers positioned inside the cooling sector and spaced from each other to allow a plurality of air ducts each defined between two adjacent spacers, and at least one electrical shield positioned in the cooling sector and arranged to electrically shield the air ducts. At least one electrical shield is positioned in the cooling sector and arranged to electrically shield the air ducts. The electrical shield include a first end edge connected to the turn at the inner side of the cooling sector, a second end edge which is free and electrically insulated from the surrounding parts, and a central portion extending between the first and second end edges and is positioned at the outer side of the spacers.