Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B17/00—Insulators or insulating bodies characterised by their form
  • H01B17/56—Insulating bodies
  • H01B17/60—Composite insulating bodies
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B19/00—Apparatus or processes specially adapted for manufacturing insulators or insulating bodies
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B17/00—Insulators or insulating bodies characterised by their form
  • H01B17/36—Insulators having evacuated or gas-filled spaces

Definitions

• the invention generally relates to a method for manufacturing hollow bodies for composite electrical insulators, during which a first helical winding is performed on a mandrel with a longitudinal axis of at least one strip material.
• the invention also relates to a hollow body for composite electrical insulator for very high, high and medium voltage, obtained by such a method.
• composite electrical insulators for very high, medium and high voltage comprise a hollow body that can have a cylindrical, frustoconical, bi-frustoconical shape, a barrel shape or any other adapted form of revolution.
• Metal reinforcements are provided at the ends of the hollow body and an elastomeric insulating envelope surrounds the hollow body forming fins.
• These hollow bodies are used more particularly envelopes for electrical equipment, such as a capacitor or an oil-insulated transformer or a gas-insulated circuit breaker under a pressure of a few bars.
• the hollow body of such a composite electrical insulator is generally made by helical winding of fibers or inorganic or organic son, such as glass fibers agglomerated with a synthetic resin capable of curing, for example epoxy resin.
• No. 4,495,381 discloses a hollow composite electrical insulator obtained by helical winding, on a rotating mandrel, of a fiber web having passed through a bath of liquid resin.
• the helical winding is made in a first direction to obtain a first layer of fibers and, once the first end of the mandrel is reached, in a second opposite direction to obtain a second layer of fibers, inverted, wound on the first layer.
• a third layer is made and so on until that the thickness of the desired wall is reached.
• the resin is then cured to obtain the finished hollow body.
• a composite electrical insulator hollow body thus delimits a gas chamber, generally a pressurized gas comprising for example SF6 gas.
• the composite electrical insulator hollow body must therefore withstand the almost constant pressure of this gas but also any overpressure related to a malfunction, for example a fault on the terminals, inducing a point overpressure generating a shock wave.
• the known composite electrical insulators are usually made of fiberglass composite materials coated with epoxy resin, a material known to be rather brittle. Attempts to manufacture a reliable epoxy resin insulation have led to relatively thick walls and thus to heavy insulators, difficult to handle during their manufacture, maintenance or repair. In addition, SF6 gas decomposition products can occur as a result of electric arcs generated during the power failure.
• the document WO 201 1/026 519 describes a composite insulator whose hollow body is made by helical winding to withstand this type of mechanical and chemical stresses.
• This hollow body comprises an undercoat obtained by helical winding of a polyester-based fabric provided under the helical winding layers of fiber web. This underlayer allows the insulator to better resist decomposition products and shock waves.
• the object of the invention is to overcome these drawbacks by proposing a method for manufacturing hollow bodies for composite electrical insulators generating less waste than known methods, easy to implement, compatible with the presence of an undercoat resistant to gas, allowing the manufacture of several hollow bodies for composite electrical insulators on the same mandrel and limiting the need to use intermediate flanges to seal the enclosure defined by the hollow body of the composite electrical insulator.
• the subject of the invention is a method for manufacturing hollow bodies for composite electrical insulators, during which a first helical winding is carried out on a longitudinal axis mandrel of at least one strip material, characterized in that that a mandrel comprising at least one at least partly spherical end shaped to produce a hollow body for a composite electrical isolator of "bell" type and at least one peripheral circular groove dividing in at least two parts the central zone separating the ends of the mandrel, this central zone being a cylinder of revolution, in that said first helical winding is carried out so as to constitute at least one hollow body for a composite electrical insulator of the "bell” type, and in that one cutting said first helical winding transversely to the longitudinal axis, following the peripheral groove to form at least two horns hollow ps for composite electrical insulators, at least one of which is of the "bell” type, and in that these two hollow bodies are axially spaced from one another to separate them from
• Helical winding is understood to mean any multi-turn helical winding comprising one or more layers, the layers being obtained by inversion of the longitudinal displacement during winding, in particular when the ends of the mandrel are reached.
• bell-type insulator is understood to mean any insulator having a "bell-like” shape, this "bell-like” shape being conventional with inversion of curvature and flared edge, or comprising a spherical portion extended by a cylindrical portion. , or any other suitable form.
• the method according to the invention thus makes it possible to simultaneously manufacture at least two insulators by limiting the amount of waste.
• the method according to the invention makes it possible to obtain isolators whose shape makes it possible to overcome the need to use an intermediate piece to ensure the tightness of the enclosure delimited by the hollow body of the insulator. .
• a rotary mandrel is advantageously used.
• a first helical winding of contiguous turns around said median zone separating the ends of said mandrel and around said end is made, at least partially covering said first helical winding.
• non-contiguous turns are meant turns that do not tangent, which are spaced a few millimeters to several centimeters apart. Non-joined turns can also intersect. Joining turns are understood to mean turns which tangent or even overlap.
• a second embodiment of the method according to the invention at least partly covers said end and the adjacent end of said median zone separating the ends of said mandrel by means of at least one envelope distinct from said strip, and thereafter, at least the edges of said envelope covering said adjacent end of said area are covered median by means of said helical winding for bonding said helical winding to said casing.
• At least one envelope having a flower petal shape whose center is provided with an orifice adapted to receive the axis of said mandrel, and whose periphery is provided with petals adapted to conform on said end and on the adjacent end of said middle zone;
• At least a first helical winding of at least a first band around said middle zone is carried out before covering said end by means of said casing and producing at least a second helical winding by means of a second band over said first winding helical and said edges of said envelope;
• said end "bell” has a shape at least partly spherical extended towards said longitudinal axis by a substantially flat portion and substantially perpendicular to said longitudinal axis.
• the invention also relates to a hollow body for composite electrical insulator, characterized in that it has a bell-like shape to constitute a composite electrical insulator of "bell" type, the top of said bell-like shape being traversed by an orifice, said bell-like shape comprising at least a substantially cylindrical "bell” portion of longitudinal axis revolution extended by a prolonged substantially spherical "bell” portion, at least within said shape of "bell” type, by a substantially flat portion of "bell” substantially perpendicular to said longitudinal axis and surrounding said orifice, said portion of substantially flat "bell” being adapted to receive the support of an elastic seal surrounding said orifice.
• the hollow body for isolator according to the invention thus makes it possible to dispense with an intermediate flange to ensure the tightness of the enclosure delimited by the hollow body.
• Said substantially flat "bell" portion preferably has a surface state having a roughness Ra of less than 3.2 ⁇ and preferably less than 0.8 ⁇ .
• Figure 1 is a bottom view of a portion of a composite electrical insulator comprising a hollow body obtained by the method according to the invention
• Figure 2 is a half-front view and a half-view in section along the sectional plane AA of Figure 1, the hollow body of Figure 1;
• Figures 3 to 7 are schematic views illustrating the steps of the manufacturing method according to a first embodiment of the invention.
• Figures 8 to 13 are schematic views illustrating the steps of the manufacturing method according to a second embodiment of the invention.
• the hollow body 2 for composite electrical insulators 1 obtained with the method according to the invention is a so-called "bell-shaped” body, the base of the "bell” being provided with a fastener 3 serving as reinforcement for anchoring the hollow body 2.
• the hollow body 2 is provided at its semi-spherical apex with a through hole 20.
• the bell-like shape comprises a substantially cylindrical "bell" portion 21 of longitudinal axis Y extended by a portion of "bell" substantially spherical 22, flattened at the top, that is to say that the orifice 20 is located in a substantially flat "bell” portion 23 surrounding the orifice 20.
• the orifice 20 has for example a diameter OD of about 140 mm. It is understood that this dimensional value as well as the following values are given for information only.
• the substantially cylindrical "bell” portion 21 may have an outside diameter D1 of about 380 mm, an internal diameter D2 of about 340 mm and therefore a substantially constant thickness E1 of about 20 mm, and a length L1 of about 330 mm.
• the substantially spherical "bell” portion 22 has, for example, an inner radius of curvature R1 of about 100 mm while maintaining the substantially constant thickness of 20 mm.
• the substantially flat "bell” portion 21 is substantially perpendicular to the longitudinal axis Y and extends over a width L2 of about 25 mm to the orifice 20. This substantially flat "bell” portion 21 has a surface condition having a roughness Ra less than 3.2 ⁇ and preferably less than 0.8 ⁇ .
• this substantially flat "bell" portion 21 is adapted to receive, directly, the support of an elastic seal (not shown) surrounding the orifice 20 for sealingly closing the enclosure delimited by the inner surface of the hollow body 2 of the composite electrical insulator 1.
• this composite electrical insulator 1 does not require an intermediate flange as is the case for composite electrical insulators substantially cylindrical or frustoconical known.
• the hollow body 2 is made of glass fibers impregnated with epoxy resin, the internal face of the bell-like shape being able to be covered by a film 24, for example made of polyester, reinforcing the mechanical and chemical characteristics of the electrical insulator. composite 1 and thus allowing it to better withstand any operating shock wave and to form a barrier to any decomposition products of the gas, for example SF6 gas, which may be contained in the composite electrical insulator 1.
• a film 24 for example made of polyester
• the manufacturing method according to the invention described below makes it possible to produce any hollow body 2 for a composite electrical insulator 1 of the "bell" type comprising or not comprising, in an inner layer, a film 24 of polyester or any other suitable material. to strengthen the protection of the body hollow 2.
• the fastener 3 is in the form of a substantially circular ring of a height H1 of about 75 mm, outer diameter D3 of about 465 mm and inner diameter D4 of about 340 mm.
• This fastener 3 comprises a bore 30 with a peripheral inner boss 31, having a diameter D5 of about 380 mm, into which the cylindrical base of the hollow body 2 bears against the peripheral inner boss 31.
• the fastener 3 comprises an annular flange provided with fastening orifices 32 distributed on its periphery, opening into bosses 33 and able to receive the passage for example of screws (not shown) for fixing the fastener 3 to a fastener. support (not shown).
• the fastener 3 further comprises three notches 34 opening radially, regularly distributed angularly on its periphery and can be used for the angular positioning of the fastener 3, and thus the hollow body 2, relative to the support.
• the fastener 3 is for example made of aluminum.
• FIGS. 3 to 13 the steps of the method for manufacturing a hollow body 2 according to the invention for a composite electrical insulator 1 are described below.
• the similar mechanical elements are assigned the same reference numbers.
• the mandrel 4 uses a mandrel 4 of longitudinal axis X, rotated by any suitable means, for example motorized pins (not shown).
• the mandrel 4 is rotated in a single direction. It is understood that the mandrel 4 can also be rotated in both directions of rotation.
• the mandrel 4 has a substantially cylindrical central zone 40 of revolution, with a longitudinal axis X, on which is provided a circular peripheral groove 41 which divides the winding surface of the central zone 40 into two distinct cylindrical portions of revolution. In this example, these two cylindrical portions of revolution are substantially of the same length along the longitudinal axis X.
• This peripheral circular groove 41 has example a width of 12 mm and a depth of 35 mm.
• the mandrel 4 is furthermore provided, at the ends of its central zone 40, with two ends 42 of "bell" type 42.
• the ends 42 have a flattened axial end 43 (visible in FIGS. 3 to 7, 8 and 9) which defines a flat surface substantially perpendicular to the longitudinal axis X.
• the ends 42 and the central zone 40 of the mandrel 4 are wound with one another.
• first band 5 to form helical turns.
• the ends 42 are covered by the turns of the first band 5 which thus defines a covering piece.
• the supply of the first band 5, not shown, is provided for example by a reel, motorized or not, coupled to voltage regulation means and means for guiding and aligning the first band 5. These means being known to those skilled in the art, they are not detailed.
• a fixed mandrel is used around which the guide and / or regulating means and or the reel is moved so as to obtain the helical winding.
• a first layer of the first helical coil 50 is obtained by the combination of the rotation of the mandrel 4 and the first web supply 5.
• a second and subsequent layers of the first helical coil 50 are similarly obtained by changing the direction axial displacement of the guide means once the end of the mandrel 4 reached.
• the rotation and feeding are adjusted so as to obtain, on the median zone 40, a first helical winding 50 of contiguous turns.
• the free end of the first band 5 can be fixed to the axis of the mandrel 4, for example by means of a node (not shown). This knot can be undone after the laying of a few helical winding turns. This avoids any extra thickness related to this node as well as any effect of white veil.
• this first helical winding 50 of the strip 5 can indifferently start from the right or the left of the mandrel with overlapping ends 42.
• a second helical winding 60 of non-contiguous turns is made.
• the second helical winding 60 may comprise several layers of superimposed turns. This second helical winding 60 is obtained for example with adjustments relating to the pitch between turns, to the speed of axial displacement of the guide means, and to the return movements of a second strip 6 between the ends 42.
• FIG. 5 illustrates only part of the second helical winding 60 which covers the first helical winding 50, including on the ends 42.
• a third helical winding 70 with contiguous turns is formed, with a strip 7, substantially similar to the first helical winding 50, and only partially shown in FIG. 6.
• the strips 5, 6, 7 of fibers used may be coated with resin before or after each helical winding, this resin being cured before or after any new helical winding.
• the resulting complex is cut off, for example by combining a rotation of the mandrel 4 and the lateral advance of a cutting tool. (not shown) towards the longitudinal axis X, following the peripheral circular groove 41. The latter is deep enough to allow the bucking tool to pass through.
• Two identical insulator hollow bodies 1 in the form of a "bell" shape are thus obtained which can be moved apart from each other along the X axis according to the arrows F to separate them from the mandrel 4. This separation can be facilitated by the use of specific tools (not shown), for example a crown of motorized traction. According to another embodiment not shown, it is possible to obtain two different insulator hollow bodies, either by using ends having different shapes, or by using a mandrel having a peripheral circular groove 41 not centered in the width of its median area 40.
• each end 42 is covered with envelopes 8, 8 '.
• the envelopes 8, 8 'thus define covering pieces.
• Each envelope 8, 8 ' is formed of a sheet of a flexible material such as a polyester film, or a composite film of fibers coated or not with liquid resin.
• each envelope may be made in a sheet of a preformed rigid material.
• each envelope 8, 8 ' has a flower petal shape.
• each flower petal shape is crossed by an orifice 80, 80 'adapted to receive the passage of the axis of the mandrel 4.
• the periphery of the flower petal shape comprises petals 81, 81', for example six, designed so that when the envelope 8, 8 'is placed on the end 42, it matches the shape of the end 42 largely covering its surface.
• the flower petal shape is designed to overlap the ends of the petals 81, 81 'with the adjacent end of the central zone 40 covered by the first winding 50.
• the envelopes 8, 8' may comprise a radial cutout (not shown) for opening them to insert them laterally on the axis of the mandrel 4.
• a radial cutout (not shown) for opening them to insert them laterally on the axis of the mandrel 4.
• the envelopes 8, 8 ' are bonded to each other and to the first winding by means of a binder known to those skilled in the art.
• a second helical winding 70 is made with contiguous turns using a second strip 7.
• This second helical winding 70 is substantially similar to the first helical winding 50, and shown in FIG. 12.
• the second helical winding 70 can be made in the same direction, or in a direction opposite to the first helical winding 50.
• This second helical winding 70 is made so as to overlap the ends of the petals 81, 81 'overlapping the first winding 50.
• the first and second strips 5, 7 may be coated with resin before or after each helical winding, this resin being cured before or after any new helical winding.
• the resulting complex is cut along the peripheral circular groove 41 in a manner similar to the first embodiment.
• the second embodiment it is possible to place one or more first envelopes before making the first helical winding and, after making the first helical winding, it is possible to lay even further envelopes superimposed on the first envelopes before making the second helical winding.
• the first and second helical windings are produced by means of non-contiguous turns intersecting each other.
• the strips 5, 6, 7 used in these processes may be strips of film, polyester yarns or fibers and / or strips of fibers or sheets of fibers, for example glass fibers and / or any other suitable strip. These strips 5, 6, 7 have for example a width of about 50 mm.
• the layers of fibers individually have, for example, a width of approximately 3 to 4 mm.
• Each winding can also be obtained with widths of strips 5, 6, 7 different, for example about 25 mm to cover the ends 42 and about 50 mm for the central zone 40.
• the bands 5, 6, 7 are made of fibers and are in the form of strands, independent of each other, parallel to each other, the alignment of the strands can be provided by a comb.
• the binder used to bind the strips 5, 6, 7 together and possibly the strips to the envelopes 8, 8 ' is a conventional binder known to those skilled in the art.
• the steps of the method according to the invention described above can be implemented to produce a resistant underlayer, for example polyester and repeated in order to achieve the layer of composite material itself.
• a mandrel having a single end provided with a "bell” type end the other end of the mandrel being conventional per se, insofar as a single "bell” type body must be manufactured on the mandrel.
• a mandrel comprising a plurality of peripheral circular grooves, for example two or more, axially spaced from one another along the longitudinal axis X to manufacture simultaneously, on the same mandrel, two hollow bodies of the " bell “and one or more, tubular hollow body type cylindrical or frustoconical.

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• Insulating Bodies (AREA)
• Moulding By Coating Moulds (AREA)

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• 2011
  • 2011-05-27 FR FR1154630A patent/FR2975814B1/fr active Active
• 2012
  • 2012-05-29 EP EP12731082.9A patent/EP2715744B1/de not_active Not-in-force
  • 2012-05-29 WO PCT/FR2012/051197 patent/WO2012164215A1/fr not_active Ceased
  • 2012-05-29 PL PL12731082T patent/PL2715744T3/pl unknown

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