Abstract: A three-phase transformer including a transformer housing, a shell-form five-limb transformer core wherein main limbs include two outer main limbs and a middle main limb, three coil arrangements including two outer coil arrangements each arranged around a respective one of the outer main limbs, and a middle coil arrangement arranged around the middle main limb. The outer coil arrangements have an inter-coil insulation configured to electrically insulate the coil arrangements from the transformer housing and from the respective other ones of the coil arrangements, and wherein no inter-coil insulation is provided to the middle coil arrangement.

Abstract: A hybrid transformer core flGf includes comprises columns (21 23) of grain-oriented steel and yokes . A yoke includes a plurality of second plies including sheets of amorphous steel adhered to each other by an adhesive coating on an outer peripheral area of major faces of the sheets of amorphous steel.

Abstract: A transformer comprises a tank having tank walls. The tank walls comprise composite panels having a core. The tank has a fluid-tight insert.

Abstract: A transformer arrangement includes a transformer having a winding and a surge arrester arrangement connected thereto. The SAA includes a surge arrester (SA) connected across at least a section of the winding and a switch operable between a closed and open state. In the closed state, SA is electrically connected across at least the section, and in the open state, the SA electrically disconnected from at least the section. The SAA includes at least one further SA arranged to be connected across at least one further section and at least one further switch, operable between a closed and open state, wherein in the closed state the further SA is electrically connected across the at least one further section, and in the open state, the at least one further SA is electrically disconnected from the further section. A method for electrically connecting/disconnecting the transformer to/from the SAA—is also described.

Abstract: The subject of the present application is a cover for distribution transformer filled with a dielectric liquid, equipped with electronic device integrated with the cover which is applied for transmission and distribution of electric energy. The cover is characterized in that the electronic device is immersed in the dielectric liquid filling a cooling compartment fixed on the cover; the cooling compartment has side walls, a top wall and a bottom wall which bottom wall is matched in the window made in the cover and the bottom wall forms a thermal barrier between the interior of the electric power device and the interior of the cooling compartment and the both interiors of the cooling compartment and of the electric power device are hermetically closed together.

Abstract: A three-phase transformer including a transformer housing, a shell-form five-limb transformer core wherein main limbs include two outer main limbs and a middle main limb, three coil arrangements including two outer coil arrangements each arranged around a respective one of the outer main limbs, and a middle coil arrangement arranged around the middle main limb. The outer coil arrangements have an inter-coil insulation configured to electrically insulate the coil arrangements from the transformer housing and from the respective other ones of the coil arrangements, and wherein no inter-coil insulation is provided to the middle coil arrangement.

Abstract: A transformer core frame is provided with a reinforcement structure to form a reinforced transformer core frame. The reinforcement structure comprises one or several reinforcement panels comprising a honeycomb structure and affixed to the transformer core frame. A method of producing a reinforced transformer core frame is also described.

Abstract: The subject of the present application is a cover for distribution transformer filled with a dielectric liquid, equipped with electronic device integrated with the cover which is applied for transmission and distribution of electric energy. The cover is characterized in that the electronic device is immersed in the dielectric liquid filling a cooling compartment fixed on the cover; the cooling compartment has side walls, a top wall and a bottom wall which bottom wall is matched in the window made in the cover and the bottom wall forms a thermal barrier between the interior of the electric power device and the interior of the cooling compartment and the both interiors of the cooling compartment and of the electric power device are hermetically closed together.

Abstract: An electrically insulating inorganic sheet including at least 90% by weight inorganic particles, and a binder which binds the particles together to form the sheet, for use as solid insulation in an electrical device, e.g. a power transformer.

Abstract: A three-phase stacked triangular transformer core is provided. The transformer has three legs and six yoke parts therebetween, wherein the legs include stacked laminations. In a cross-sectional plane perpendicular to a central transformer core axis, the stacked laminations are oriented in substantially radial direction, and each leg has two leg halves, wherein each leg half has a plurality of outer corners facing a corresponding leg half of a neighboring leg. For each of the leg halves the plurality of outer corners lie on a respective straight line within a lateral tolerance, and for each leg half the straight line defined by this leg half and the straight line defined by the corresponding leg half of the neighboring leg are parallel.

Abstract: A method for manufacturing a stacked triangular core transformer includes assembling a triangular core by positioning of two halves of one leg on an assembly stand in the horizontal position; securing the positioned halves; positioning an outer clamping beam underneath two leg halves at the one end of the leg halves; assembling a yoke segment at the one end of two halves of the core leg; and forming a first clamp of the frame. The method continues by forming a second clamp of the frame at the other end of the two halves of the core leg by repeating the above positioning, assembling and forming steps; tightening the clamps together by securing means; rotating a single core frame into vertical position and releasing securing bar of the assembly stand; assembling two additional single core frames by repeating the above steps; positioning the frames in abutting position, and tightening them together.

Abstract: A three-phase stacked triangular transformer core is provided. The transformer has three legs and six yoke parts therebetween, wherein the legs include stacked laminations. In a cross-sectional plane perpendicular to a central transformer core axis, the stacked laminations are oriented in substantially radial direction, and each leg has two leg halves, wherein each leg half has a plurality of outer corners facing a corresponding leg half of a neighboring leg. For each of the leg halves the plurality of outer corners lie on a respective straight line within a lateral tolerance, and for each leg half the straight line defined by this leg half and the straight line defined by the corresponding leg half of the neighboring leg are parallel.

Abstract: A disconnector for distribution transformers with dielectric liquid intended for comprehensive protection of a power grid or for protecting distribution transformers. The disconnector provides at least two cylindrical current-limiting fuses located inside a transformer tank. Each fuse is electrically connected with an external phase power supply through fixed contacts and moving contacts of the disconnector with the active part of the transformer. The disconnector has an additional auxiliary contact which is electrically connected to a switch connected to the active part of the transformer on a low voltage side of the transformer.

Abstract: A disconnector for distribution transformers with dielectric liquid intended for comprehensive protection of a power grid or for protecting distribution transformers. The disconnector provides at least two cylindrical current-limiting fuses located inside a transformer tank. Each fuse is electrically connected with an external phase power supply through fixed contacts and moving contacts of the disconnector with the active part of the transformer. The disconnector has an additional auxiliary contact which is electrically connected to a switch connected to the active part of the transformer on a low voltage side of the transformer.