EP4179554A1 - Electrical conductors for power transformers with high electrical and thermal conductivity - Google Patents

Electrical conductors for power transformers with high electrical and thermal conductivity

Info

Publication number
EP4179554A1
EP4179554A1 EP21743453.9A EP21743453A EP4179554A1 EP 4179554 A1 EP4179554 A1 EP 4179554A1 EP 21743453 A EP21743453 A EP 21743453A EP 4179554 A1 EP4179554 A1 EP 4179554A1
Authority
EP
European Patent Office
Prior art keywords
metal
phase
layer
copper
wire rod
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP21743453.9A
Other languages
German (de)
French (fr)
Inventor
Roberto Preda
Vincenzo Tagliaferri
Nadia UCCIARDELLO
Silvio GENNA
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Co Trafil Production Srl
Original Assignee
Co Trafil Production Srl
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Co Trafil Production Srl filed Critical Co Trafil Production Srl
Publication of EP4179554A1 publication Critical patent/EP4179554A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/32—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/32—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer
    • C23C28/321—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer with at least one metal alloy layer
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/32—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer
    • C23C28/322—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer only coatings of metal elements only
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/34—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/2847—Sheets; Strips
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/02—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of sheets

Definitions

  • the present invention relates to a process for manufacturing electrical conductors for power transformers with high electrical and thermal conductivity, enhanced through the deposition of copper and graphene.
  • the present invention relates to an industrial process for the production of conductors having a rectangular section in copper and/or aluminium coated with GNP graphene (Graphene NanoPlatelets) with different thicknesses, in order to increase thermal and electrical conductivity of said conductors, which are then used in all the windings for electrical machines, transformers, generators, motors and, in particular, the power transformers.
  • GNP graphene Graphene NanoPlatelets
  • the transformer i a static electric machine powered by alternating current, based on the phenomenon of electromagnetic induction, intended to transform, between the primary circuit (input) and the secondary circuit (output) of the transformer, the voltage and current factors of the electric power.
  • the transformer therefore transfers the electric power from an electric circuit to another, which has a different voltage, coupling them inductively, without the transformer windings coming into contact with each other.
  • An electric current transformer in the primary winding generates a variable magnetic flux in the core of the transformer and consequently a variable magnetic field across the secondary winding (Faraday's law and Lenz's law).
  • This variable magnetic field induces an electromotive force, or voltage, in the secondary winding. This effect is called mutual induction.
  • the transformer is, therefore, a machine capable of operating essentially in alternating current, because it generally exploits the principles of electromagnetism linked to variable flows.
  • the efficiency of a transformer is very high and the losses are very low (in iron, due to the hysteresis and eddy currents, and in copper, due to the Joule effect).
  • a transformer To reduce the decrease in performance, a transformer must have the following characteristics: ⁇ Windings: o as few coils as possible o minimum length: the winding wire must be as short as possible; generally this depends on the section and shape of the core, square or (better still, where possible) circular. ⁇ Core: o a suitable section; o a length as short as possible; o in ferromagnetic material so as to have an electrical resistance as high as possible, to minimize losses due to the Joule effect and a coercive force as low as possible, in order to have a hysteresis cycle as tight as possible
  • Cooling the cooling is necessary to prevent the overheating of the transformer due to the dissipated power. It is particularly important in the transformers operating at high powers.
  • the cooling can be: o with air - typical solution of normal civil transformers and for small powers; o in oil bath - the transformers work in an oil bath in suitably shaped metal casings to facilitate heat dispersion; o in forced oil bath - compared to the oil bath system, there are also pumps for the forced circulation of the oil and a system of external fans to increase heat removal; o in resin - compared to the other systems, the windings are immersed in a special resin, which makes them dissipate the heat. This resin takes the place of oil. Size benefits can be gained from the resin transformer, since they are slightly smaller than an oil transformer.
  • transformers are recognized according to their cooling method.
  • the type of cooling is recognized by a code consisting of two or four letters (two, if the transformer has a single cooling; four, if the cooling is double).
  • the first letter shows what type of substance is being used for cooling (e.g. oil, resin, air)
  • the second letter shows the type of fluid circulation inside the transformer (natural or forced circulation).
  • transformer types are recognized:
  • WO20 14/ 141071 reports a method for the preparation of coated metal foams (through an electrodeposition process) with a metal matrix and graphene.
  • EP0859381A1 mentions an electrical conductor for the low voltage windings (and high currents), which allows greater heat exchange, maintaining the same performance as a transformer, which has, however, a much greater encumbrance. This allows the manufacturing of a power transformer having reduced dimensions, thus saving large quantities of copper during the construction of said transformer.
  • the present invention relates to a process for manufacturing electrical conductors for power transformers with high electrical and thermal conductivity, enhanced through the deposition of copper and graphene.
  • the present invention relates to an industrial process for the production of conductors having a rectangular section in copper and/or aluminium coated with GNP graphene (Graphene NanoPlatelets) with different thicknesses, in order to increase thermal and electrical conductivity of said conductors which are then used in all the windings for electrical machines, transformers, generators, motors and in particular the power transformers.
  • GNP graphene Graphene NanoPlatelets
  • a metal wire rod is drawn with special synthetic diamond and/or tungsten carbide dies, using an emulsion bath of water and oil. The drawing step is necessary to reduce the diameter of said metal wire rod until a circular section having a diameter of 1.8 mm is reached.
  • a metal wire rod is defined as a round object made of metallic material, which usually has a cylindrical shape. Said metal wire rod:
  • • is made of a metal selected from the group comprising: aluminium, silver, nickel, gold, copper and/or their alloys; preferred are copper and aluminium.
  • Phase 2 - Laminating and edging The metal wire rod obtained at the end of phase 1 is shaped through a laminating and edging process to obtain a metal strip (having a rectangular section) that complies with the IEC (International Electrotechnical Commission) tolerance standards and has the following characteristics:
  • the metal strip obtained at the end of phase 2 is subjected to a thermal cooking cycle, optionally having the following temperatures and the following time intervals: cooking at a temperature of 550°C for a period of time of 4 hours (parameters usually used for copper strips), using an electric oven for static cooking in an inert atmosphere (nitrogen), to restore the metal to a soft and malleable physical state.
  • a thermal cooking cycle optionally having the following temperatures and the following time intervals: cooking at a temperature of 550°C for a period of time of 4 hours (parameters usually used for copper strips), using an electric oven for static cooking in an inert atmosphere (nitrogen), to restore the metal to a soft and malleable physical state.
  • Step 1 - the metal strip is coated with a “first metal layer”, deposited using a physical deposition technique (PVD/physical vapor deposition) or with a chemical deposition technique (CVD/ chemical vapor deposition), as described in Adv. Mater. 2000, 12, No. 9;
  • Step 2 - on the first metal layer of step 1 a “second metal layer (or its alloys) and graphene” is deposited/ stratified, using the electrodeposition described in W02014141071, wherein the metal associated with the graphene can be the same or different from the one used in step 1 ;
  • Step 3 - on the second “metal and graphene” layer of step 2 a “third metal layer” (or its alloys) is deposited/ stratified through a further electrodeposition process as described W02014141071, or a chemical or physical vapor deposition process using the PVD or CVD procedure as described in http:/ / www. mag- data. com/ dettaqli-tecnici/ introduuite-ai-film-polimerici/ ; Journal of Materials Chemistry C Volume 4 Number 37, 7 October 2016, Pages 8585-8830; and/or Adv. Mater. 2000, 12, No. 9.
  • the metal material of the first, the second and third layer is selected from the group comprising: aluminium, silver, nickel, gold, copper and/or their alloys; the metal of the first layer can be the same of different from the second layer, which can in turn be the same of different from the metal of the third layer.
  • the electrodeposited metal strip obtained at the end of phase 4 is insulated through a taping process, using a material selected from the group comprising: pure cellulose paper for oil impregnation, aramid paper, mica tape and/or polyamide tape. Phase 6 - Coupling the metal strips thus obtaining the power transformer.
  • the strips obtained at the end of phase 5 are grouped or coupled (depending on the transformer to be made) in helical windings, disc windings or other types of windings, thus obtaining the desired power transformer.
  • Said power transformer can be used in the industrial, industrial, energy, naval and / or aerospace field and having better characteristics of electrical and thermal conductivity, dissipated power and efficiency compared to current transformers on the market.
  • the metal strip obtained at the end of phase 5 which can be used for the construction of windings for electrical machines, transformers, generators and / or motors.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Coils Of Transformers For General Uses (AREA)
  • Insulated Conductors (AREA)
  • Non-Insulated Conductors (AREA)

Abstract

A process for manufacturing electrical conductors for power transformers with high electrical and thermal conductivity, enhanced through the deposition of copper and graphene, is herein described. In particular is described an industrial process for the production of conductors in copper and/or aluminium having a rectangular section (strips) coated with graphene, in order to increase thermal and electrical conductivity of said conductors, which are then used in all the windings for power transformers.

Description

ELECTRICAL CONDUCTORS FOR POWER TRANSFORMERS WITH HIGH ELECTRICAL AND THERMAL CONDUCTIVITY FIELD OF THE INVENTION
The present invention relates to a process for manufacturing electrical conductors for power transformers with high electrical and thermal conductivity, enhanced through the deposition of copper and graphene. In particular, the present invention relates to an industrial process for the production of conductors having a rectangular section in copper and/or aluminium coated with GNP graphene (Graphene NanoPlatelets) with different thicknesses, in order to increase thermal and electrical conductivity of said conductors, which are then used in all the windings for electrical machines, transformers, generators, motors and, in particular, the power transformers.
BACKGROUND OF THE INVENTION The transformer i a static electric machine powered by alternating current, based on the phenomenon of electromagnetic induction, intended to transform, between the primary circuit (input) and the secondary circuit (output) of the transformer, the voltage and current factors of the electric power.
The transformer therefore transfers the electric power from an electric circuit to another, which has a different voltage, coupling them inductively, without the transformer windings coming into contact with each other.
An electric current transformer in the primary winding generates a variable magnetic flux in the core of the transformer and consequently a variable magnetic field across the secondary winding (Faraday's law and Lenz's law). This variable magnetic field induces an electromotive force, or voltage, in the secondary winding. This effect is called mutual induction.
The transformer is, therefore, a machine capable of operating essentially in alternating current, because it generally exploits the principles of electromagnetism linked to variable flows. The efficiency of a transformer is very high and the losses are very low (in iron, due to the hysteresis and eddy currents, and in copper, due to the Joule effect).
To reduce the decrease in performance, a transformer must have the following characteristics: · Windings: o as few coils as possible o minimum length: the winding wire must be as short as possible; generally this depends on the section and shape of the core, square or (better still, where possible) circular. · Core: o a suitable section; o a length as short as possible; o in ferromagnetic material so as to have an electrical resistance as high as possible, to minimize losses due to the Joule effect and a coercive force as low as possible, in order to have a hysteresis cycle as tight as possible
(and therefore magnetic losses as low as possible).
• Cooling: the cooling is necessary to prevent the overheating of the transformer due to the dissipated power. It is particularly important in the transformers operating at high powers. The cooling can be: o with air - typical solution of normal civil transformers and for small powers; o in oil bath - the transformers work in an oil bath in suitably shaped metal casings to facilitate heat dispersion; o in forced oil bath - compared to the oil bath system, there are also pumps for the forced circulation of the oil and a system of external fans to increase heat removal; o in resin - compared to the other systems, the windings are immersed in a special resin, which makes them dissipate the heat. This resin takes the place of oil. Size benefits can be gained from the resin transformer, since they are slightly smaller than an oil transformer.
For this purpose, various types of transformers are recognized according to their cooling method. The type of cooling is recognized by a code consisting of two or four letters (two, if the transformer has a single cooling; four, if the cooling is double). Specifically, in the code the first letter shows what type of substance is being used for cooling (e.g. oil, resin, air), the second letter shows the type of fluid circulation inside the transformer (natural or forced circulation). For this purpose, the following transformer types are recognized:
• NA: with natural air circulation (not forced);
• NO: with natural oil circulation;
• FA: with forced air circulation;
• NANO: with natural air and oil circulation;
• FAFO: with forced air and oil circulation.
WO20 14/ 141071 reports a method for the preparation of coated metal foams (through an electrodeposition process) with a metal matrix and graphene. EP0859381A1 mentions an electrical conductor for the low voltage windings (and high currents), which allows greater heat exchange, maintaining the same performance as a transformer, which has, however, a much greater encumbrance. This allows the manufacturing of a power transformer having reduced dimensions, thus saving large quantities of copper during the construction of said transformer.
DESCRIPTION OF THE INVENTION
The present invention relates to a process for manufacturing electrical conductors for power transformers with high electrical and thermal conductivity, enhanced through the deposition of copper and graphene.
In particular, the present invention relates to an industrial process for the production of conductors having a rectangular section in copper and/or aluminium coated with GNP graphene (Graphene NanoPlatelets) with different thicknesses, in order to increase thermal and electrical conductivity of said conductors which are then used in all the windings for electrical machines, transformers, generators, motors and in particular the power transformers.
Applying graphene on the surface of such conductor having a rectangular section, it is possible to increase the electrical conductivity and thus allowing the same current flow in a smaller section and, at the same time, improving the thermal conductivity. This means, being able to make a conductor with the same electrical performance, but much smaller in size and therefore much less expensive. In addition, the improved thermal conductivity allows for better heat dissipation and further prevents damage from hot spots and thermal aging. In particular, for the power transformers it is extremely important to be able to design and build machines more and more efficient and less expensive, in our case because the total volume of transformers have a significantly reduced total volume. It is therefore object of the present invention the manufacturing of metal conductors having a rectangular section for transformers (metal strips) electrodeposited with graphene, obtained through the following processing steps. Phase 1 - Drawing the metal wire rod
The metal wire rod is drawn with special synthetic diamond and/or tungsten carbide dies, using an emulsion bath of water and oil. The drawing step is necessary to reduce the diameter of said metal wire rod until a circular section having a diameter of 1.8 mm is reached. According to the present invention, a metal wire rod is defined as a round object made of metallic material, which usually has a cylindrical shape. Said metal wire rod:
• generally has a circular section, with a diameter between 8 mm and 20 mm;
• is made of a metal selected from the group comprising: aluminium, silver, nickel, gold, copper and/or their alloys; preferred are copper and aluminium.
Phase 2 - Laminating and edging The metal wire rod obtained at the end of phase 1 is shaped through a laminating and edging process to obtain a metal strip (having a rectangular section) that complies with the IEC (International Electrotechnical Commission) tolerance standards and has the following characteristics:
• width between 2 mm and 25 mm; length between 2 mm and 25 mm; • thickness between 0.9 mm and 8 mm.
Phase 3 - Static cooking in an inert atmosphere (nitrogen)
The metal strip obtained at the end of phase 2 is subjected to a thermal cooking cycle, optionally having the following temperatures and the following time intervals: cooking at a temperature of 550°C for a period of time of 4 hours (parameters usually used for copper strips), using an electric oven for static cooking in an inert atmosphere (nitrogen), to restore the metal to a soft and malleable physical state. Phase 4 - Electrodepositing on the metal strips
The metal strip obtained at the end of phase 3 is coated through the subsequent steps:
Step 1 - the metal strip is coated with a “first metal layer”, deposited using a physical deposition technique (PVD/physical vapor deposition) or with a chemical deposition technique (CVD/ chemical vapor deposition), as described in Adv. Mater. 2000, 12, No. 9; Step 2 - on the first metal layer of step 1 a “second metal layer (or its alloys) and graphene” is deposited/ stratified, using the electrodeposition described in W02014141071, wherein the metal associated with the graphene can be the same or different from the one used in step 1 ;
Step 3 - on the second “metal and graphene” layer of step 2 a “third metal layer” (or its alloys) is deposited/ stratified through a further electrodeposition process as described W02014141071, or a chemical or physical vapor deposition process using the PVD or CVD procedure as described in http:/ / www. mag- data. com/ dettaqli-tecnici/ introduzione-ai-film-polimerici/ ; Journal of Materials Chemistry C Volume 4 Number 37, 7 October 2016, Pages 8585-8830; and/or Adv. Mater. 2000, 12, No. 9. The metal material of the first, the second and third layer is selected from the group comprising: aluminium, silver, nickel, gold, copper and/or their alloys; the metal of the first layer can be the same of different from the second layer, which can in turn be the same of different from the metal of the third layer. Phase 5 - Insulating the electrodeposited strips through taping
The electrodeposited metal strip obtained at the end of phase 4 is insulated through a taping process, using a material selected from the group comprising: pure cellulose paper for oil impregnation, aramid paper, mica tape and/or polyamide tape. Phase 6 - Coupling the metal strips thus obtaining the power transformer.
The strips obtained at the end of phase 5 are grouped or coupled (depending on the transformer to be made) in helical windings, disc windings or other types of windings, thus obtaining the desired power transformer.
Said power transformer can be used in the industrial, industrial, energy, naval and / or aerospace field and having better characteristics of electrical and thermal conductivity, dissipated power and efficiency compared to current transformers on the market.
The increase in electrical conductivity of the metal strips and of the power transformer, obtained at the end of the phases 5 and 6 of the present invention, led to a reduction of the resistivity of the initial material (copper) between 5% and 9%. This reduction in resistivity is associated, for the same section, with a decrease in the heat generated by the Joule effect, also between 5% and 9%. Furthermore, an appropriate sizing and optimization of the shapes of the contacts and the geometry of the surrounding areas has contributed, in addition to a further reduction of at least 5% of the thermal load, also to a homogenization of temperatures with a reduction of hot spots.
It is a further object of the present invention the metal strip obtained at the end of phase 5, which can be used for the construction of windings for electrical machines, transformers, generators and / or motors.

Claims

1. Process for the preparation of a power transformer, comprising the following processing steps:
• Phase 1 - drawing a metal wire rod: a metal wire rod is drawn with special synthetic diamond and/or tungsten carbide dies, using an emulsion bath of water and oil.;
• Phase 2 - laminating and edging: the metal wire rod obtained in phase
1 is shaped through a laminating and edging process to achieve a metal strip having a rectangular section;
• Phase 3 - static cooking: the metal strip obtained at the end of phase
2 is subjected to a thermal cooking cycle at a temperature of 550°C for a period of time of 4 hours, using an electric oven for static cooking in an inert atmosphere, to restore the metal to a soft and malleable physical state;
• Phase 4 - electrodepositing: the metal strip obtained at the end of phase 3 is coated through the subsequent steps:
- Step 1 - the metal strips are coated with a first metal layer, deposited using the vapour physical deposition technique (PVD) or the vapour chemical deposition technique (CVD);
- Step 2 - on the first metal layer of step 1 a second metal and graphene layer is deposited, using the electrodeposition technique;
- Step 3 - on the second metal and graphene layer of step 2 a third metal layer is deposited using the vapour physical deposition technique, the vapour chemical deposition technique or the electrodeposition; and wherein:
- the metal material of the first, second and third layer is selected from the group comprising: aluminium, silver, nickel, gold, copper and/or their alloys;
- the metal material of the first layer can be the same of different from the second layer, which can in turn be the same of different from the metal of the third layer;
• Phase 5 - insulating the electrodeposited strips: the electrodeposited metal strip obtained at the end of phase 4 is insulated through a taping process;
• Phase 6 - coupling or grouping: the strips obtained at the end of phase 5 are grouped or coupled in helical windings, disc windings or other types of windings, thus achieving the power transformer. 2. Process of claim 1, wherein the metal wire rod of phase 1:
• has a circular section, having a diameter between 8 mm and 20 mm;
• is made of a metal selected from the group comprising: aluminium, silver, nickel, gold, copper and / or their alloys; preferred are copper or aluminium; · is drawn with synthetic diamond and/or tungsten carbide dies, using an emulsion bath of water and oil.
3. Process of claim 1, wherein the metal strip obtained at the end of phase 2 has a width between 2 mm and 25 mm, a length between 2 mm and 25 mm and a thickness between 0.9 and 8 mm.
4. Process of claim 1, wherein the taping of phase 5 it is carried out using a material chosen from the group comprising: pure cellulose paper for oil impregnation, aramid paper, mica tape and/or polyamide tape.
EP21743453.9A 2020-07-13 2021-07-12 Electrical conductors for power transformers with high electrical and thermal conductivity Withdrawn EP4179554A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT102020000016903A IT202000016903A1 (en) 2020-07-13 2020-07-13 ELECTRICAL CONDUCTORS FOR POWER TRANSFORMERS WITH HIGH ELECTRICAL AND THERMAL CONDUCTIVITY.
PCT/EP2021/069298 WO2022013138A1 (en) 2020-07-13 2021-07-12 Electrical conductors for power transformers with high electrical and thermal conductivity

Publications (1)

Publication Number Publication Date
EP4179554A1 true EP4179554A1 (en) 2023-05-17

Family

ID=72644753

Family Applications (1)

Application Number Title Priority Date Filing Date
EP21743453.9A Withdrawn EP4179554A1 (en) 2020-07-13 2021-07-12 Electrical conductors for power transformers with high electrical and thermal conductivity

Country Status (3)

Country Link
EP (1) EP4179554A1 (en)
IT (1) IT202000016903A1 (en)
WO (1) WO2022013138A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20240047096A1 (en) * 2022-08-03 2024-02-08 Infineon Technologies Austria Ag Graphene in electromagnetic systems

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3419835A (en) * 1967-03-29 1968-12-31 Westinghouse Electric Corp Electrical winding structures
IT1290307B1 (en) 1997-02-13 1998-10-22 Invex Fili Isolati Speciali S TRANSPOSED CABLE FOR MAKING WINDINGS IN ELECTRIC MACHINES, ITS MAKING PROCESS, AND MAKING METHOD
DE10339867B4 (en) * 2003-08-25 2007-12-27 Leibniz-Institut Für Festkörper- Und Werkstoffforschung Dresden E.V. Method for the production of metallic flat wires or tapes with cube texture
ITRM20130146A1 (en) 2013-03-12 2014-09-13 Stefano Guarino ELECTROPOSITION ON METAL FOAMS
CN103943226A (en) * 2014-05-09 2014-07-23 浙江大学 Electric wire and cable with nickel-graphene complex phase protection layer and preparation method of electric wire and cable
EP3053688B1 (en) * 2015-02-06 2019-10-09 Agie Charmilles SA Graphene electrode and method of producing such electrode
IT201700020695A1 (en) * 2017-03-14 2018-09-14 Vincenzo Tagliaferri New electrical or data transmission cables with high electrical conductivity and / or high data transmission speed.

Also Published As

Publication number Publication date
IT202000016903A1 (en) 2022-01-13
WO2022013138A1 (en) 2022-01-20

Similar Documents

Publication Publication Date Title
Wang et al. Analysis and comparison between no-insulation and metallic insulation REBCO magnet for the engineering design of a 1-MW DC induction heater
EP2704161A1 (en) Magnetic core for magnetic component with winding, containing improved means of cooling
US10986701B2 (en) Movable core induction heating apparatus
Wrobel et al. Comparative study of copper and aluminium conductors-future cost effective PM machines
EP3477669A1 (en) High power capacitor
Simpson et al. Design of high performance shaped profile windings for additive manufacture
Wrobel et al. Design considerations of heat guides fabricated using additive manufacturing for enhanced heat transfer in electrical machines
Bardalai et al. Comparative Analysis of AC losses with round magnet wire and Litz wire winding of a High–Speed PM Machine
EP3093961A2 (en) Windings for electrical machines
EP4179554A1 (en) Electrical conductors for power transformers with high electrical and thermal conductivity
CN105553136A (en) Motor stator iron core
Bobba et al. Multi-physics based analysis and design of stator coil in high power density PMSM for aircraft propulsion applications
Wrobel et al. Winding loss separation in thermal analysis of electromagnetic devices
CN205565915U (en) Do benefit to refrigerated motor stator structure
WO2004047494B1 (en) Induction heating work coil
RU2669576C2 (en) High slip variable frequency induction motor
EP3961868A1 (en) Electric machine
WO2022094308A1 (en) Aluminum-carbon metal matrix composite magnet wires
Szucs et al. Diamond enriched lamination and winding insulation for electrical machines
CN204906042U (en) Motor and winding wire rod
CN101060260A (en) Core winding for generator, motor and transformer
CN206628349U (en) A kind of novel transformer
JP2014099323A (en) Thin film superconducting wire rod and superconducting coil
Chaw et al. Design comparison for rectangular and round winding distribution transformer (1000 kVA)
Del Ferraro et al. Aluminium multi-wire for high-frequency electric machines

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: UNKNOWN

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20230207

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20230905