Abstract: A primary coil suitable for use in a transformer includes a primary winding bobbin onto which a layer of a primary winding and at least one layer, which includes a fixed number of 1 to 3 layers, of an interlayer insulation material are wound alternately, wherein the interlayer insulation material and the primary winding are impregnated with an epoxy, and wherein the interlayer insulation material is a nonwoven material or a crepe paper.

Abstract: A high voltage (HV) apparatus insulated with an insulating gel includes at least two electrically conductive elements, such as a head transformer cover, a head housing base, a core casing, a primary conductor, bottom external housing, a bottom support flange, and/or a core. At least one of the electrically conductive elements has a coating made of solid insulating material separating the surface of the conductive element from the insulating gel and adapted for limiting electron emission from the conductive elements into the insulating gel.

Abstract: The present invention refers to HV apparatus, in particular a HV dry current transformer, insulated with an insulating gel, or a voltage transformer, insulated with an insulating gel. The dry HV current transformer comprises at least two electrically conductive elements i.e. a head transformer cover, a head housing base, a core casing and a primary conductor. In the dry HV current transformer at least one of the electrically conductive elements has a coating made of solid insulating material separating the surface of the conductive elements from the insulating gel and adapted for limiting the electron emission from the conductive elements into the insulating gel. The voltage transformer comprises a bottom external housing, a bottom support flange, a core.

Abstract: A dry high voltage (HV) instrument transformer in the form of a HV current transformer includes a core casing having a secondary winding, a top housing, a primary winding, and a dry bushing, wherein the core casing comprises an insulation containing an electrically insulating material made of PES nonwoven impregnated and cured with low viscosity epoxy. The dry HV instrument transformer in the form of a HV voltage transformer includes a bottom tank housing, a cast of a primary winding module with an embedded screen surrounding the primary winding, a field grading disc, and a core, wherein the cast of the primary winding module is made of an insulating composite containing an electrically insulating material made of PES nonwoven impregnated and cured with low viscosity epoxy.

Abstract: The present invention refers to HV apparatus, in particular a HV dry current transformer, insulated with an insulating gel, or a voltage transformer, insulated with an insulating gel. The dry HV current transformer comprises at least two electrically conductive elements i.e. a head transformer cover, a head housing base, a core casing and a primary conductor. In the dry HV current transformer at least one of the electrically conductive elements has a coating made of solid insulating material separating the surface of the conductive elements from the insulating gel and adapted for limiting the electron emission from the conductive elements into the insulating gel. The voltage transformer comprises a bottom external housing, a bottom support flange, a core.

Abstract: A method of manufacturing a polymer-insulated conductor. The method includes the steps of a) providing a conductor having a first cross-sectional shape, b) passing the conductor through a conductor-shaping die to shape the conductor such that the conductor obtains a second cross-sectional shape, wherein frictional heat is developed in the conductor, thereby setting the conductor in a heated state, c) applying molten polymer to the conductor when the conductor is in the heated state to obtain a polymer-coated conductor, and d) shaping the polymer-coated conductor by means of a polymer-shaping die to thereby obtain the polymer-insulated conductor.

Abstract: A method of manufacturing a polymer-insulated conductor. The method includes the steps of a) providing a conductor having a first cross-sectional shape, b) passing the conductor through a conductor-shaping die to shape the conductor such that the conductor obtains a second cross-sectional shape, wherein frictional heat is developed in the conductor, thereby setting the conductor in a heated state, c) applying molten polymer to the conductor when the conductor is in the heated state to obtain a polymer-coated conductor, and d) shaping the polymer-coated conductor by means of a polymer-shaping die to thereby obtain the polymer-insulated conductor.