EP0441140A1 - Isoliermaterial für ölgefüllte elektrische Einrichtungen - Google Patents

Isoliermaterial für ölgefüllte elektrische Einrichtungen Download PDF

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Publication number
EP0441140A1
EP0441140A1 EP91100532A EP91100532A EP0441140A1 EP 0441140 A1 EP0441140 A1 EP 0441140A1 EP 91100532 A EP91100532 A EP 91100532A EP 91100532 A EP91100532 A EP 91100532A EP 0441140 A1 EP0441140 A1 EP 0441140A1
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EP
European Patent Office
Prior art keywords
resin
dielectric constant
insulator
layers
oil
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Withdrawn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
EP91100532A
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English (en)
French (fr)
Inventor
Minoru Hatakeyama
Fumihiro Sasaki
Jinichi Wada
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.)
Japan Gore Tex Inc
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Japan Gore Tex Inc
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 Japan Gore Tex Inc filed Critical Japan Gore Tex Inc
Publication of EP0441140A1 publication Critical patent/EP0441140A1/de
Withdrawn legal-status Critical Current

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    • 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
    • H01F27/32—Insulating of coils, windings, or parts thereof
    • H01F27/323—Insulation between winding turns, between winding layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/008—Other insulating material

Definitions

  • the present invention relates to insulators for use in oil-filled electrical devices such as the transformers used in electrical power generation or for industrial purposes.
  • An insulator which consists of an insulating oil and a pressboard with a low dielectric constant in which polymethylpentene fibers and cellulose fibers have been blended.
  • the dieletric constant of this insulator is 3.5.
  • the dielectric constant of insulators consisting of an insulating oil and conventional pressboard is 4.7. If a comparison of the dielectric breakdown voltage in relation to an impulse voltage is made between the two insulators, the partial discharge commencement voltage and the dielectric breakdown voltage are at least 30% higher when the low-dielectric constant pressboard is used than with the current insulators. Specifically, it is known that the closer is the dielectric constant of the insulator to the dielectric constant of the oil alone (2.2), the more the increase in the above voltage values will be.
  • the present invention makes use of a composite of a continuously porous fluorinated resin or aramide resin, or one of these and another resin with a low dielectric constant in place of pressboard, crepe paper, draft paper, or the like.
  • the invention is an insulator for use in oil-filled electrical devices, which is characterized by the fact that continuously porous fluorinated resin or aramide resin sheets are used after being impregnated with an insulating oil.
  • Polytetrafluoroethylene (PTFE) fluorinated ethylene propylene copolymer (FEP), perfluoroalkoxy tetrafluoroethylene (PFA), ethylene tetrafluoroethylene copolymers (ETFE), vinylidene fluoride (PVFD), and similar compounds can be utilized for the fluorine resin.
  • Fluorine resins and aramide resins are generally distinguished by low dielectric constants.
  • the dielectric constant of the PTFE itself is 2.1, and while the dielectric constant of a continuously porous sheet of PTFE which has been impregnated with an insulating oil (dielectric constant of 2.2) will vary depending on the volumeric ratio of the PTFE and the insulating oil, it will be close to the dielectric constant of the insulating oil, and the dielectric breakdown voltage of the insulators will be increased.
  • the dielectric constant of aramide resins is 2.6 to 2.7.
  • PTFE and other fluorinated resins and aramide resins are substances that are extremely stable with respect to chemicals and temperature, with no deterioration attributable to increased temperature, thus allowing insulators to be produced with a high level of reliability that will last for many years.
  • the range that the strength of the insulator will tolerate the higher the porosity, the lower and more desirable will be the dielectric constant as a whole, but there are no particular restrictions placed on this.
  • the invention is an insulator for use in oil-filled electrical devices, which is characterized by the fact that it is composed of a laminate of continuously porous fluorinated resin or aramide resin layers and resin layers whose dielectric constant is 3.5 or less, wherein said continuously porous fluorinated resin or aramide resin layers are used after being impregnated with an insulating oil.
  • This arrangement is effective when the mechanical strength in the compression direction will not be sufficient with continuously porous fluorinated resin or aramide resin layers alone.
  • the reason for stipulating a dielectric constant of 3.5 or less for the resin is that this is useful when the dielectric strength of the insulators is increased by making the electrostatic focusing smaller and minimizing the difference between the dielectric constant of 2.2 of the insulating oil and the dielectric constant of the insulators.
  • polyimides, polyether ether ketone (PEEK), polyether sulfone (PES), and other similar resins are desirable. Since a given fluorine resin or aramide resin will have a greater mechanical strength in the form of a solid resin layer than as a porous resin layer, the above arrangement can be used to this end.
  • the continuously porous fluorinated resin or aramide resin layers and resin layers whose dielectric constant is 3.5 or less can be alternatively laminated in the required number of layers.
  • the present invention is an insulator for use in oil-filled electrical devices, which is characterized by the fact that it is composed of continuously porous layers formed by leaving spaces between continuously porous fluorinated resin or aramide resin layers and then packing the spaces with a resin whose dielectric constant is 4.0 or less, wherein an insulating oil is used for impregnation in the continuously porous resin layers.
  • This arrangement is, as above, useful when the compression strength is insufficient and there is a need for the insulation distance to be maintained.
  • the reason for stipulating a dielectric constant of 4.0 or less for the resin to be impregnated is that the resin is compounded with a fluorinated resin with a low dielectric constant and is then impregnated with an insulating oil, which means that the overall dielectric constant is lowered, and the focussing of the electrical field can be made smaller.
  • Ethoxy resins, polyimide resins, bismalidetriazine resins (BT resins), fluorine resins, polyphenylene oxide (PPO) resins, and other similar thermosetting or thermoplastic resins can be used for the above resin, and these may be used singly or in mixtures.
  • an insulating oil By leaving spaces between the resin layers used to pack the pores of the fluorinated resin or between aramide resin layers, an insulating oil can be used to impregnate these spaces.
  • a characteristic of this arrangement is that the porosity of the continuously porous fluorinated resin or aramide resin layers, the amount and type of resin used to pack the fluorinated resin or aramide resin layers, and the final porosity after the resin packing can be adjusted depending on the dielectric constant and the mechanical strength required of the insulators, and are not set at fixed values.
  • the present invention is an insulator for use in oil-filled electrical devices, which are characterized by the fact that they are formed from solid layers in which continuously porous fluorinated resin or aramide resin layers are completely packed with a resin whose dielectric constant is 4.0 or less. Moreover, the handling characteristics of the insulators in this case are enhanced.
  • the continuously porous fluorinated resin or aramide resin sheets or layers include continuously porous moldings of extruded or drawn sheets, non-woven cloth, fibrous cloth, yarn cloth, and other fluorinated resin or aramide resin products having continuous pores.
  • an insulator sheet was produced by bundling four sheets of the porous PTFE sheet 1, which had a thickness of 1.6 mm and a porosity of 30%.
  • This insulator sheet was used as the insulator between the coils, as shown in Figure 6, and was put in an insulating oil such as mineral oil, dielectric constant 2.2.
  • an insulating oil such as mineral oil, dielectric constant 2.2.
  • the dielectric constant of the insulator sheet in an insulating oil- impregnated state was 2.15.
  • the same type of insulator sheet as that above was then produced in a thickness of 6.4 mm from conventional pressboard, and upon measuring the dielectric breakdown voltage in the same manner as above, it was found to be 200 kv.
  • the dielectric constant was 4.7.
  • Example 2 Upon subjecting to the same test as in Example 1 an insulator sheet with a thickness of 6.4 mm and in which, as is shown in Figure 2, the porous PTFE sheet 1, which had a thickness of 1.6 mm and a porosity of 30%, and the solid PTFE sheets 2 (0.8 mm thick) were alternately layered, the dielectric constant was found to be 2.14, and the dielectric breakdown voltage had been increased to nearly the same 330 kv as in Example 1.
  • Example 2 Upon subjecting to the same test as in Example 1 an insulator sheet with a thickness of 6.4 mm and in which, as is shown in Figure 3, the porous PTFE sheets 1, which had a thickenss of 1.6 mm and a porosity of 30%, and the polyimide sheets 3 (0.8 mm thick) were alternately layered, the dielectric constant was found to be 3.2, and the dielectric breakdown voltage had been increased to 300 kv. It was found that the deformation of the insulators due to the tightening force in the compression direction of the coils was lower than in Examples 1 and 2.
  • porous PTFE sheet 1 which had a thickness of 0.25 mm and a porosity of 80%, was 30% impregnated with polyimide resin 4 (dielectric constant of 3.1), and was compressed to 0.2 mm with a hot press and the polyimide resin hardened (in Figure 4, 5 is the spaces).
  • This product was used as an insulating sheet, and 32 of these insulating sheets were bundled together to form an insulator sheet with a thickness of 6.4 mm.
  • the dielectric constant was found to be 2.4 and the dielectric breakdown voltage had been increased to nearly 320 kv.
  • Porous PTFE sheet 1 which had a thickness of 0.3 mm and a porosity of 80%, was impregnated with epoxy resin 6 (dielectric constant of 2.6) and was then compressed to 0.2 mm with a hot press and the epoxy resin hardened. This product was used as an insulating sheet, and 32 of these insulating sheets were bundled together to form an insulator with a thickness of 6.4 mm. Upon subjecting this insulator to the same test as in Example 1, the dielectric constant was found to be 2.4, and the dielectric breakdown voltage due to impulse voltage was 320 kv, nearly the same as in Example 4.
  • Figure 6 shows a transformer as an example of oil-filled electrical devices.
  • coils in which the windings 14 are wound around the iron cores 13, are immersed in the insulating oil of the transformer tank 11, and are connected to the bushing 16 via the lead wire 15.
  • a soundproofing tank is denoted as 16 and a cooling device as 17.
  • Figure 7 shows a detail of the coils, wherein the windings 14 are constructed such that insulation 22 is wound around the straight angle copper wires 21, and an insulator 23 is interposed between the individual windings to insulate them.
  • the rails 24 and the insulated tube 25, among other components are also the principal insulator of tie oil-filled electrical device is a continuously porous PTFE or aramide resin of layers which is impregnated with an insulating oil such as mineral oil.
  • Figure 8 is shown a structure in which the windings 31 (straight angle copper wires wound with insulation) are bundled with the insulators 32, and if needed, the solid layers 33 interposed between these insulators.
  • the insulators of the present invention can also be used as these insulators 32. In other words, they can be used for any of the insulators in an oil-filled electrical device.
  • the porous PTFE utilized in the invention may be the porous expanded PTFE described in U.S. Patent Nos. 3,953,566, 3,962,153, 4,096,227, 4,187,390, 4,902,423, or 4,478,665, or may be made by other methods of stretching or by extracting a soluble material from a filled PTFE or aramide resin by a suitable solvent.
  • An aramide resin may also be made porous by dissolving it in solvent, molding the solution, then removing the solvent.
  • Other fluorinated resins than PTFE can be made porous by use of a foaming agent or an extraction process, such as that above.
  • the dielectric constant of continuously porous fluorinated resin or aramide resin sheets or layers is less than that of pressboard, crepe paper, or the like, the dielectric constant of the overall insulators impregnated with insulating oil will also be reduced. Also, the mechanical strength can be increased by laminating a solid resin layer with continuously porous fluorinated resin or aramide resin layers or by packing the pores with another resin. By limiting the dielectric constant of these resins to a specific value or less, the dielectric constant of the insulators as a whole will be lower than conventional insulators made of pressboard or the like. Further, fluorinated resins and aramide resins are chemically and thermally stable, making them excellent insulators.
EP91100532A 1990-02-07 1991-01-17 Isoliermaterial für ölgefüllte elektrische Einrichtungen Withdrawn EP0441140A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2025962A JP2959789B2 (ja) 1990-02-07 1990-02-07 油入電器用絶縁物
JP25962/90 1990-02-07

Publications (1)

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EP0441140A1 true EP0441140A1 (de) 1991-08-14

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EP91100532A Withdrawn EP0441140A1 (de) 1990-02-07 1991-01-17 Isoliermaterial für ölgefüllte elektrische Einrichtungen

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JP (1) JP2959789B2 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996008828A1 (en) * 1994-09-13 1996-03-21 W.L. Gore & Associates, Inc. Jacket material for protection of electrical conductors

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8085120B2 (en) * 2009-08-13 2011-12-27 Waukesha Electric Systems, Incorporated Solid insulation for fluid-filled transformer and method of fabrication thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH579812A5 (de) * 1971-05-24 1976-09-15 Westinghouse Electric Corp
US4187390A (en) * 1970-05-21 1980-02-05 W. L. Gore & Associates, Inc. Porous products and process therefor
DE2815451B2 (de) * 1977-09-08 1981-05-21 Mitsubishi Electric Corp., Tokyo Verfahren zur Herstellung von ölimprägnierbarer Isolierpappe

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4187390A (en) * 1970-05-21 1980-02-05 W. L. Gore & Associates, Inc. Porous products and process therefor
CH579812A5 (de) * 1971-05-24 1976-09-15 Westinghouse Electric Corp
DE2815451B2 (de) * 1977-09-08 1981-05-21 Mitsubishi Electric Corp., Tokyo Verfahren zur Herstellung von ölimprägnierbarer Isolierpappe

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996008828A1 (en) * 1994-09-13 1996-03-21 W.L. Gore & Associates, Inc. Jacket material for protection of electrical conductors
US5519172A (en) * 1994-09-13 1996-05-21 W. L. Gore & Associates, Inc. Jacket material for protection of electrical conductors
US5846355A (en) * 1994-09-13 1998-12-08 W. L. Gore & Associates, Inc. Jacket material for protection of electrical conductors

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Publication number Publication date
JP2959789B2 (ja) 1999-10-06
JPH03233808A (ja) 1991-10-17

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