Abstract: A transformer cooling system, includes a dry transformer having a core including a leg, a winding body arranged around the leg, and a cooling channel extending in a direction of a longitudinal axis of the winding body. The cooling channel is disposed between an inner part of the winding body and an outer part of the winding body. The transformer cooling system further includes a housing for containing the dry transformer. The housing has an inlet portion for receiving air from outside the housing and an outlet portion for expelling air outside the housing. The transformer cooling system further includes a flow generating device arranged at the outlet portion and adapted to generate an under pressure for sucking the air from the inlet portion towards the flow generating device and to expel the air through the outlet portion outside the housing.

Abstract: An arrangement to cool a coil, comprising an enclosure, which at least partially incorporates or houses the coil, and a device to create an airflow to cool the coil, wherein the coil comprises at least one cooling channel to guide the airflow through the windings of the coil and an outer air duct lying radially in the outer circumference area of the coil or lying radially inside below an outer part of the coil, characterized in that an air guidance plate is placed at or near one longitudinal end of the outer air duct and/or of the coil to prevent bypasses of the airflow and/or to block at least partially the airflow through and/or along the outer air duct, achieves the object to cool a coil, especially a coil of a transformer, in an efficient manner using space-saving means.

Abstract: A dry transformer to be mounted on or under or in a vessel or means of transportation, in particular a rail car or power car of a train or a ship, includes at least one core and at least one winding. The winding surrounds the core and the core and the winding are parts of a coil. The coil and/or the core and/or the winding are mechanically connected to an outer support structure by at least one strut. The transformer is able to master the required typical dynamic loads in at least one direction in transportation applications, such as railway applications.

Abstract: A transformer cooling system is described. The transformer cooling system includes a dry transformer and a housing for the dry transformer. The dry transformer includes a core including a leg. Additionally, the dry transformer includes a winding body arranged around the leg. Further, a cooling channel extending in a direction of a longitudinal axis of the winding body is provided. Additionally, the transformer cooling system includes a heat exchanger adapted to dissipate heat from the housing. Further, the transformer cooling system includes a flow generating device arranged in the housing for providing a cooling flow in the cooling channel. The flow generating device is connected to the heat exchanger.

Abstract: An air-cooled dry-type transformer includes: a core provided with a branch; a winding body arranged about the branch; a cooling channel extending in a direction of a longitudinal axis of the winding body, the cooling channel being arranged between an inner part of the winding body and an outer part of the winding body, the cooling channel having openings at both ends and a substantially ring-shaped cross section with a round, oval, or polygonal basic shape; and at least one ring ventilator comprising a ring and a blower. The blower suctions air and blows the air from the ring along a longitudinal axis of the ring, thereby generating an air flow. The at least one ring ventilator is dimensioned and mounted such that the air flow generates a cool air flow in the cooling channel.

Abstract: A dry transformer load switch, and transformer having such switch, has a hollow insulation cylinder extending longitudinally about a virtual center axis and has a plurality of connection contacts arranged along the inner circumference thereof, and a radially oriented main contact arranged in the interior of the hollow insulation cylinder so as to be rotatable about the center axis and which, with a corresponding rotary movement, can be optionally electrically connected by the radially outer end thereof to one of the connection contacts. In a hollow-cylindrical space about the center axis that is defined by the radially inner and outer end of the main contact, there is a barrier shield, which can be rotated together with the main contact about the axis.

Abstract: A transformer arrangement and transformer for mitigating transient voltage oscillations. The transformer included a transformer core enclosing at least one core leg. A winding is wound around one of the at least one core leg. The winding extends from a first winding terminal to a second winding terminal and includes a first winding section along a first conductor extending from the first winding terminal to a first intermediate end point, and a second winding section along a second conductor extending from a second intermediate end point to the second winding terminal. The transformer arrangement further includes an external passive electric component connected between the first intermediate end point and either the second intermediate end point or the second winding terminal arranged to decrease an effective difference between capacitive and inductive voltage distributions between the intermediate end points such that transient voltage oscillations in the winding are mitigated.

Abstract: An exemplary transformer protection system including a protective housing having a transformer which is arranged in the protective housing, a transformer core, and at least one primary-side electrical winding and a secondary-side electrical winding which is magnetically coupled to the primary-side electrical winding. The protection system also includes at least one detection apparatus for a measurement variable from which the occurrence of an interference arc within the protective housing can be derived, and an evaluation unit for generating a fault signal from the measurement variable of the at least one detection apparatus in the case of an interference arc. Further, the protection system includes at least one rapid-earthing apparatus for at least one of the electrical windings which is intended to be activated by the fault signal, wherein the rapid-earthing apparatus is designed in such a way that effective electrical earthing immediately after activation of the fault signal is ensured.

Abstract: An on-load tap-changer for dry transformers, having an electric insulating hollow casing extending around a virtual axis, wherein several electric contact sections are foreseen along a path on the inner surface of the hollow casing, which are electrically joined through the wall of the hollow casing and a selector contact in the inner of the cylinder which is moveable along the path and that's outer end is selectively connectable with one of the contact sections by a respective movement. Respective cables are foreseen to electrically connect the contact sections from the radial outer side of the hollow casing, wherein at least some of the cables have a respective surrounding outer insulation at least at their respective connected end.

Abstract: According to an embodiment, the invention provides a voltage control system for medium voltage applications. The voltage control system provides a booster-transformer and a feeder-transformer, each of the booster-transformer and the feeder-transformer having a respective primary winding and a secondary winding, wherein the secondary winding of the feeder-transformer is electrically connected with the primary winding of the booster-transformer by an intermediate circuit. The voltage control system also includes a connection device configured to connect the secondary winding of the booster transformer with an electrical energy supply network in order that the secondary winding of the booster transformer is connected in series with a transmission line having a voltage that is to be controlled.

Abstract: A dry transformer load switch, and transformer having such switch, has a hollow insulation cylinder extending longitudinally about a virtual center axis and has a plurality of connection contacts arranged along the inner circumference thereof, and a radially oriented main contact arranged in the interior of the hollow insulation cylinder so as to be rotatable about the center axis and which, with a corresponding rotary movement, can be optionally electrically connected by the radially outer end thereof to one of the connection contacts. In a hollow-cylindrical space about the center axis that is defined by the radially inner and outer end of the main contact, there is a barrier shield, which can be rotated together with the main contact about the axis.

Abstract: Exemplary embodiments relate to a system and method for monitoring functional operational reliability of a cooling system having at least one thermosyphon for transformers provided with at least one evaporator and with at least one condenser. The cooling system using a coolant which can be vaporized and a gaseous medium, as a heat carrier.

Abstract: A high-voltage transformer and method of manufacturing are disclosed. The high-voltage transformer can include a transformer core having at least two core limbs, which are axially parallel and on which in each case a hollow-cylindrical coil having in each case at least one electrical winding is arranged. At least in partial regions of mutually facing surfaces of adjacently arranged coils, the respective surface regions of the coils can have a respective electrically isolating barrier structure, which can be integrated radially on an outside of the coil.

Abstract: An exemplary arrangement includes blocks arranged between the inner winding, the individual barriers and the outer winding in order to maintain defined spacing's along the circumference. At least two coils are arranged axially one above the other on a common core limb. Each coil has at least two windings arranged radially one above the other and barriers are provided between the windings. The barriers of adjacent coils are radially offset with respect to one another, and the edge regions of the barriers engage one another in a comb-like manner.

Abstract: A transformer arrangement and transformer for mitigating transient voltage oscillations. The transformer included a transformer core enclosing at least one core leg. A winding is wound around one of the at least one core leg. The winding extends from a first winding terminal to a second winding terminal and includes a first winding section along a first conductor extending from the first winding terminal to a first intermediate end point, and a second winding section along a second conductor extending from a second intermediate end point to the second winding terminal. The transformer arrangement further includes an external passive electric component connected between the first intermediate end point and either the second intermediate end point or the second winding terminal arranged to decrease an effective difference between capacitive and inductive voltage distributions between the intermediate end points such that transient voltage oscillations in the winding are mitigated.

Abstract: According to an embodiment, the invention provides a voltage control system for medium voltage applications. The voltage control system provides a booster-transformer and a feeder-transformer, each of the booster-transformer and the feeder-transformer having a respective primary winding and a secondary winding, wherein the secondary winding of the feeder-transformer is electrically connected with the primary winding of the booster-transformer by an intermediate circuit. The voltage control system also includes a connection device configured to connect the secondary winding of the booster transformer with an electrical energy supply network in order that the secondary winding of the booster transformer is connected in series with a transmission line having a voltage that is to be controlled.

Abstract: A transformer winding and a dry-transformer are disclosed, which include a main transformer winding, and a supplementary transformer winding configured to be electrically connected in series with the main transformer winding. The supplementary transformer winding can include a first winding module, a second winding module, and a third winding module, each of the winding modules having at least a first, a second and a third winding segment, and wherein each of the winding segments has a tap. A changer is configured to be connected to the taps of the second winding module, and wherein the second winding module is configured to be electrically connected in series to at least one winding segment of the first winding module and the third winding module.

Abstract: An on-load tap-changer for dry transformers, having an electric insulating hollow casing extending around a virtual axis, wherein several electric contact sections are foreseen along a path on the inner surface of the hollow casing, which are electrically joined through the wall of the hollow casing and a selector contact in the inner of the cylinder which is moveable along the path and that's outer end is selectively connectable with one of the contact sections by a respective movement. Respective cables are foreseen to electrically connect the contact sections from the radial outer side of the hollow casing, wherein at least some of the cables have a respective surrounding outer insulation at least at their respective connected end.

Abstract: A single- or multi-phase dry-type transformer includes at least two coils. A barrier between phases made of an electrically insulating material is arranged in the intermediate space between the individual coils.

Abstract: At least two winding modules nested hollow-cylindrically one inside the other and extending around a common winding axis, wherein said winding modules are spaced radially apart from one another within at least one hollow-cylindrical cooling channel arranged therebetween by means of insulation strips, wherein the insulation strips have a cross-sectional form which avoid a surface profile radially with respect to the winding axis, the insulation strips including one of a fiber-reinforced epoxy, polyester resin, or from an unreinforced thermoplastic material.