Abstract: The present disclosure relates to a condenser bushing including a condenser core and electrically conductive field-grading layers, which are embedded in insulating material of the condenser core and arranged around a central channel for conductor extending along an axis defining an axial direction, while an electric connection is provided to at least one of the field-grading layers, wherein pairs of neighbouring field-grading layers with the insulation material between them form sections of the condenser core of axial lengths L1 through Ln and with capacitances C1 through Cn, characterized in that a shape of at least one of the field-grading layers deviates from cylindricality in order to reduce non-uniformity of electric field stress of the condenser bushing compared to a corresponding condenser bushing with the cylindrical field-grading layers forming sections of the axial lengths L1 through Ln and with capacitances C1 through Cn.

Abstract: The present disclosure relates to a bushing including an electrical conductor comprising a terminal at a first end of the bushing. The bushing also includes an electrically insulating condenser core arranged around the conductor and defining a central longitudinal through-hole through which the conductor extends. The bushing also includes a plurality of concentric field-grading layers arranged in the condenser core, comprising an inner field-grading layer and an outer field-grading layer. The bushing also includes an electrically conductive head electrically connected with the conductor passing there through, forming a gas-tight cap of the first end of the bushing outside of the condenser core, sealingly engaging a circumferential lateral outer surface of the condenser core and sealingly engaging the conductor. The bushing also includes an electrically conductive connection between the inner field-grading layer and the head.

Abstract: A cooling apparatus for a medium voltage or high voltage switchgear includes an evaporator, a fluid conduit, and a condenser. The evaporator is configured to surround at least part of a current carrying contact. The fluid conduit fluidly connects the evaporator to the condenser. A section of the fluid conduit is formed within the evaporator and is electrically insulating and is configured such that fluid can contact an outer surface of the current carrying contact. The cooling apparatus is configured such that in use a working fluid in the evaporator is heated to a vapour state, and the vapour is transferred by the fluid conduit to the condenser. The vapour in the condenser is condensed to the working fluid. The condensed working fluid is passively returned via the fluid conduit to the evaporator.

Abstract: A cooling system for a medium voltage switchgear includes a conductor, a fluid conduit, and an insulator, wherein, the conductor extends in a longitudinal axis, wherein, the conductor is configured to carry electrical current in the longitudinal axis direction, wherein a first part of the fluid conduit is located around an outer surface of the conductor and extends around the longitudinal axis, wherein, a second part of the fluid conduit is connected to the first part of the fluid conduit and extends substantially perpendicularly to the longitudinal axis, wherein the insulator is located around the conductor at the position of the fluid conduit and covers the first part of the fluid conduit, and wherein the cooling system is configured such that a fluid can flow into the second part of the fluid conduit and from the second part of the fluid conduit into the first part of the fluid conduit.

Abstract: The present disclosure relates to a bushing including an electrical conductor comprising a terminal at a first end of the bushing. The bushing also includes an electrically insulating condenser core arranged around the conductor and defining a central longitudinal through-hole through which the conductor extends. The bushing also includes a plurality of concentric field-grading layers arranged in the condenser core, comprising an inner field-grading layer and an outer field-grading layer. The bushing also includes an electrically conductive head electrically connected with the conductor passing there through, forming a gas-tight cap of the first end of the bushing outside of the condenser core, sealingly engaging a circumferential lateral outer surface of the condenser core and sealingly engaging the conductor. The bushing also includes an electrically conductive connection between the inner field-grading layer and the head.

Abstract: The present disclosure relates to a condenser bushing including a condenser core and electrically conductive field-grading layers, which are embedded in insulating material of the condenser core and arranged around a central channel for conductor extending along an axis defining an axial direction, while an electric connection is provided to at least one of the field-grading layers, wherein pairs of neighbouring field-grading layers with the insulation material between them form sections of the condenser core of axial lengths L1 through Ln and with capacitances C1 through Cn, characterized in that a shape of at least one of the field-grading layers deviates from cylindricality in order to reduce non-uniformity of electric field stress of the condenser bushing compared to a corresponding condenser bushing with the cylindrical field-grading layers forming sections of the axial lengths L1 through Ln and with capacitances C1 through Cn.

Abstract: A cooling apparatus for a medium voltage or high voltage switchgear includes an evaporator, a fluid conduit, and a condenser. The evaporator is configured to surround at least part of a current carrying contact. The fluid conduit fluidly connects the evaporator to the condenser. A section of the fluid conduit is formed within the evaporator and is electrically insulating and is configured such that fluid can contact an outer surface of the current carrying contact. The cooling apparatus is configured such that in use a working fluid in the evaporator is heated to a vapour state, and the vapour is transferred by the fluid conduit to the condenser. The vapour in the condenser is condensed to the working fluid. The condensed working fluid is passively returned via the fluid conduit to the evaporator.

Abstract: A method of making sand casting moulds with a protective coating for a multiple process of reactive moulding of insulation components and products made by filling up a mould cavity with polymer materials, including composites, based particularly on epoxy resins or composites based on cellulose materials, the method wherein the process of infiltration of the mould structure is performed chemically by soaking through the raw mould structure with chemosetting or thermosetting material. The application of a protective layer on external surfaces of a sand casting mould is done by means of any spraying, immersion or deposition method, whereas material with anti-adhesive properties is used for the protective coating in the form of organic chemosetting, thermosetting, light-curing material or in the form of inorganic material, including metal.

Abstract: A method of making sand casting moulds with a protective coating for a multiple process of reactive moulding of insulation components and products made by filling up a mould cavity with polymer materials, including composites, based particularly on epoxy resins or composites based on cellulose materials, the method wherein the process of infiltration of the mould structure is performed chemically by soaking through the raw mould structure with chemosetting or thermosetting material. The application of a protective layer on external surfaces of a sand casting mould is done by means of any spraying, immersion or deposition method, whereas material with anti-adhesive properties is used for the protective coating in the form of organic chemosetting, thermosetting, light-curing material or in the form of inorganic material, including metal.