DE2119952A1 - Outdoor high voltage suspension isolator - Google Patents

Description

DR. BEFSQ ^; Ι. ·. ! ΓΙΟ- STAPK

a MÜNCHEN 80, WAL, ~ i KiRC. 1ER3TR. 45 2119952

CIBA - GEIGY AG, BASEL '(SWITZERLAND)

April 23, 1971

( Case 7024/1 + 2 / E

OLkU

Preiluft high-voltage suspension insulator

The invention relates to an outdoor high-voltage Suspension insulator with a tensile core, in particular a fiberglass-plastic rod, and a weather-resistant one hardened plastic jacket with core and jacket are mechanically connected to one another by at least one web made of compact, flexible material, the web spacers are preferably filled with fine-pored, volume expandable material. 109845/1353

The invention further relates to a method for producing such insulators.

The main problem with such insulators is an optimal connection between core and jacket. So far, no plastic has become known for the jacket, which has both sufficient tensile strength and ductility as well as sufficient electrical surface properties resistant to outdoor use. It is still failed. To connect core and jacket with one another with simple means in such a way that the jacket on the one hand is sufficient is firmly connected to the core, but on the other hand the forces transferred from the tensile core to the jacket always lie below the load limits admissible for the jacket, and that also the dielectric strength of the area between the core and the cladding is sufficiently large.

In a known outdoor high voltage suspension isolator with a fiberglass-plastic core and a ceramic jacket is to compensate for temperature-related different volume changes of the core and sheath, the intermediate layer connecting the core and sheath with cavities provided, which surround the core in a helical or annular shape and can be filled with foam. In each between the core and the jacket, the cylindrical coaxial section is the ratio between the sums of all compact

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material cut surfaces and cavity or foam cut surfaces many times greater than one. This known construction can probably be the underlying Task of equalizing temperature-related stresses can be fulfilled. The known construction is however, by no means suitable for those optimally loaded by mechanical tensile stresses and thereby optimally stretched core to reduce the forces transmitted to its jacket to such an extent that any damage or destruction of the coat is avoided.

It has now been found that by significantly increasing the cavity or foam cross-sections at the expense of the compact material cross-sections, an optimal connection between core and jacket can be established, which is sufficiently shear-deformable to ensure power transmission even with the maximum permissible core load or expansion in the jacket to a level that is permissible for this and still mechanically and electrically sufficiently strong Connection between these two parts guaranteed.

The isolator according to the invention is characterized in that that the volume occupied by the web or the sum of the volumes occupied by all webs is at most the total volume of the space between the webs is the same that the web or the webs are shaped and arranged or are so that the compressibility of their overall

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This means, including spaces, in macroscopic terms, by a multiple, in particular at least ten times, is above that of the web material.

A preferred embodiment of the isolator is characterized in that in each one through the central axis of the insulator, the height of the webs averaged over the radial extension is equal to or less is than the height of the web spaces, which is also averaged over the radial extent.

In the case of core-sheath insulators of the type according to the invention, the force transmitted from the loaded core to the sheath is known to be greater, the longer the insulator or sheath can be kept below the load limit admissible for the jacket. According to a preferred variant of the invention, this measure consists in the fact that at least one expansion-membrane-type bulged ring shell is inserted into the jacket, the bulge of which is for the most part filled with a fine-pored, volume-expandable material, which in turn is embedded in a compact, flexible material.

The known insulator described above is made up of a prefabricated core and a prefabricated core Sheath manufactured in such a way that first band or ring

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shaped, cavity-forming elements are attached to the inner surface of the jacket, the fiberglass-plastic core is positioned coaxially in the jacket, the two end fittings are installed, the potting compound is filled in through a hole in the upper fitting and
this hole is closed.

In contrast to this, the manufacturing method according to the invention consists in that the cavity-forming element or the cavity-forming elements are attached to the core, that the core occupied with the cavity-forming element or the cavity-forming elements is positioned in a first casting mold and encased with a first liquid casting resin compound, which is flexible in the hardened state, that the composite body formed in this way is positioned in a second casting mold having the desired shell shape, and that the between this second casting mold
and the gap left free on the composite body surface ~ -

with a second liquid casting resin compound

fills, which in the hardened state is optimal electrical
Has surface properties.

The construction of the insulator according to the invention or its production also has the additional advantage that internal
Tension is prevented.

In the following the invention is explained in more detail with reference to the drawing, for example; show it:

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Pig. ί to 3 three embodiments of the Isolator each in axial section,

Pig. 4 and 5 show two stages of a preferred manufacturing process for the insulator of the pig. 1 each in axial section and

Pig. 6-8 three stages of a preferred manufacturing process for the isolator of Fig. 3 each in axial section.

The drawings are true to scale and the relationships between the individual ones that can be seen from them Dimensions represent a preferred design variant.

In the pig. 1 and 2 are the fiberglass-plastic rod forming the core with 1 and the insulator jacket with 2 designated. The core and jacket are connected to one another by webs 3 made of a laminated flexible plastic. Between these Stegsa 3 is from manufacturing technology (! round and to improve the electrical properties a profile 4 wound around the core 1 made of compressible Foam embedded = The fiberglass-plastic rod 1, hereinafter referred to as GRP rod ^ is with end loops Is equipped in which a bolt eye in the form of a thin metal sleeve 5 can be embedded. The loop

a metal ring 6 or

Is is to increase their cleavage resistance with / a fiberglass plastic -Bandage provided = below the metal can 5 an ICeIl 7 made of glass fiber plastic is inserted, its Fibers are oriented parallel to the can axis. The Isolatorkopi Is ^. di ^ ir; encapsulated in a sheet metal hood 8,

which is tightly connected to the insulator jacket 2 in the manner of an expansion membrane 8d. The profiles 4 can be different Have cross-sectional shapes and arrangements. The profiles shown have a rectangular cross-section on. The transitions between the webs 3 and the core and / or jacket can be rounded off in the manner of a fillet be.

In the exemplary embodiment in FIG. 1, the profile 4 is wound helically around the core 1. The helix can be continuous or interrupted as shown, i.e. divided into sections. The illustrated Helical lines have a uniform gradient over their length. However, helical lines are preferred chosen, which are flatter in their two end areas than in the middle part. '

The profiles 4 of FIG. 2 are placed in a ring around the core 1. The distances between these Rings equal to or against the insulator ends can be selected to decrease.

The foam profiles 4 can also be replaced by hoses.

To suppress glow discharges, the foam profiles 4 can be electrically weak or semiconducting layer, e.g. a suitable lacquer. Likewise, the hoses can inside and / or

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be coated on the outside with such a layer and / or filled with an electrical extinguishing gas, in particular sulfur hexafluoride (SF, -). Profile sections coated with an electrically weakly or semiconducting layer are preferably arranged in such a way that these sections are in contact with one another. In the case of interrupted helical lines, this is achieved by overlapping contact with the ends of the helical line sections. The two outermost ends of the foam profiles or hoses are electrically connected to the insulator poles (sleeve 5) sheet metal hood 8), which can also be achieved by appropriate laek layers.

Protection against corona discharge and electrical breakdowns can be further increased by the Core 1 and / or the inner surface of the jacket 2 likewise with an electrically weak or semiconducting layer, in particular 'such a lacquer layer are coated

FIG. 3 shows a central section of a very long insulator, the upward and downward continuations of which coincide with the insulator of FIG. In accordance with FIG. 1, the following are again denoted: with 1 the glass fiber-plastic rod, with 2 the jacket, with 3 the webs and with k the foam parts. The pontic, designated 100 as a whole, is new. The intermediate link

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100 consists of a hard shell .102, a layer made of flexible, compact material and an insert 104 made of compressible, fine-pored material. The shell 4 is Bulging like an expansion membrane and cast in one piece with the insulator jacket. The layer 103 is cast onto the webs 3.

The isolator can also be equipped with a plurality of expansion membrane-like intermediate members (102) and therefore manufactured as long as required. The sections of the jacket 2 lying between these members can almost be one another deform independently of each other. As a result, even with insulators of any length, the stressed core on the Sheath transmitted tensile forces are always kept below the load limits permissible for the sheath.

At the insulator the pig. 3, the ends of the fiberglass-plastic rod 1 according to Pig. I be trained. In all the exemplary embodiments, the fiberglass-plastic wedge denoted by 7 can be filled with a wedge Replace epoxy resin.

In the pig. 1 to 4 show the webs in axial section a rectangular cross-section, likewise the web spaces or foam inserts 4. The height hS of the webs 3 is smaller than their radial extent

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rS and less than the height hZ of the spaces. In space-, common, i.e. in the case of webs with a height that changes over their radial expansion [nS = f (rS) J, the arrangement is made as follows., that the height of the webs averaged over the radial extent is equal to or smaller than that over the same radial extension, mean height of the spaces and that the mean web height is preferably smaller as the radial first deflection of the webs.

The isolator of Flg. 1 is preferably produced in the following steps:

First of all, the fiberglass-plastic core 1, referred to below as a GRP rod, is produced. For this purpose, glass silk strands (rovings) are impregnated with liquid resin / hardener misöbung in a soaking bath and wound in a ring-shaped manner , whereby an approximate semicircular cross-section of the wound ring is achieved by guiding the glass silk strands to be wound up accordingly.

After the resin contained in the * ira wound ring / Hardener-öemisoh part of the hardening reaction at elevated temperature has expired «, becomes the ring, which is still easily deformable stretched by means of sweeping bolts and together with the bolts inserted into the lower part © Ines pressing tool. ' There, where the bundle of strands divides, around the bolt Au ürasshlingeRf prefabricated wedges 7 made of quartz powder-filled

i.

Cast resin inserted.

109846/1383

When the upper press tool is pressed on, excess resin / hardener mixture is squeezed out. Only during the gelling of the resin / hardener mixture, the upper part of the pressing tool is pressed into its final position, whereby the GRP rod receives its dimensions.

After the hardening in the heated press tool has been completed, the GPK rod is demolded, deburred, degreased with a solvent and mechanically roughened, preferably by sandblasting.

The degreased and roughened GRP rod is preferred coated with the resin / hardener mixture used for the production of the highly flexible encapsulation. Afterward a degreased foam rubber profile 4 with a rectangular cross-section is placed on the sticky surface of the rod wound helically under tension. Before the profile is rolled up, it can be painted electrically weakly or semiconducting lacquer can be applied. The loaded ends of the foam rubber profile are by means of a sheet or Wire clip pressed against the GPK rod and thereby fixed. (The ones cast into the highly flexible resin Metal staples are later removed by cutting away the outer ends of the highly flexible layer.) At elevated temperatures the resin / hardener mixture is gelled.

Even before the resin / hardener mixture used to glue the foam rubber profile to the GPK rod is complete

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2119902

is gelled, the wound GRP rod is made according to Pig. 4 inserted into a first casting mold with a cylindrical cavity. The shape is in two parts. The parting line lies in the plane of the drawing. In the figure, therefore, only the rear mold half is 60 visible. At both ends, the mold is held against the GRP rod by means of sealing rings pulled over the loop head 61 sealed. The two mold halves are sealed against each other by a sealing cord, which lies in a groove that is in the parting plane in the front and therefore invisible mold half with respect to the plane of the drawing is incorporated. While the mold is set up so that the longitudinal axis runs in a vertical direction, is the same resin / hardener mixture that was previously used for the Bonding between the foam rubber profile and GRP rod was used, from below from a storage vessel via a plastic tube (not shown) pressed into the mold through a sprue opening 62 with a slight excess pressure. With advancing The mold can be filled in order to keep the flow rate more or less constant as the flow resistance increases to keep the overpressure at the sprue gradually to about 0.5 atu raise.

After the cavity remaining between the wrapped GRP rod and the mold wall, completely filled with resin / hardener mixture is filled, the resin / hardener mixture flows out of the upper outlet opening-63 of the mold into a plastic tube (not shown) over. The lower plastic hose is disconnected

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stuck and separated from the resin storage vessel (not shown). After that, the mold is used to equalize the pressure in its Tilted horizontal position, the two with resin / hardener mixture filled plastic tubes are held with their opening facing upwards so that no resin leaks out. To Removing the hose clamp on the sprue side puts the pressure on the liquid columns in both hoses due to atmospheric pressure.

An additional overpressure to push in the resin / hardener mixture to compensate for the reaction loss in the form is not necessary, because the volume elasticity of the foam rubber ensures that no significant internal stresses in the hardened one due to the reaction shrinkage highly flexible casting resin is created.

After hardening at an elevated temperature, the highly flexible cast GRP rod is removed from the mold and the outer one Ends of the highly flexible layer containing the metal clips, cut off. Possibly on the flexible overlay Adhesive release agent is removed by washing with solvent removed. This operation is not necessary if the mold is lined with Teflon, which means a release agent treatment unnecessary. Finally, the surface of the highly flexible encapsulation, which is later replaced with the hard encapsulation? cast should bond well, mechanically roughened, preferably by sandblasting. Finally, the

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The encapsulation can be covered with a layer of electrically weak or semiconducting lacquer.

According to FIG. 5, in a second casting mold, the interior of which has the shape of the insulator jacket, the GPK rod, which is already provided with the highly flexible sheath, is centrally fixed and, similarly as previously described, the rod is sealed against the mold and the two mold halves against each other. This second mold is also in two parts. The parting line is again in the plane of the drawing and the rear mold half JO is visible. The seal against the GRP rod is made by two sealing rings 71. The mold 70 is heated to a temperature which is higher than that of the casting compound ^ which in this case is a resin / hardness mixture containing fillers (quartz powder and aluminum oxide trihydrate). This mixture is also from below _s filled through an opening 72 in the stationary mold with a slight overpressure to casting mass at the upper opening 73 of the mold exit. The casting mold is preferably located in a vacuum chamber (not shown) so that the insulator jacket is free of air bubbles right into the screens. After the casting compound has hardened at an elevated temperature, the insulator is removed from the mold. The insulator jacket is deburred.

There vjo the optic cord heads Is of the GRP rod 1 merge into the cylindrical shaft (l), a split metal ring is clamped onto the rod, which in the case of the

1 0ä84B / 1383

2119112

Tensile load on the rod splitting of the rod as a result of the change in direction of the strand that takes place there prevented. Then the prefabricated sheet metal hood 8 (Fig. 1) is slipped over the loop head and with the end of the insulator jacket glued after the adhesive surfaces have been degreased and roughened in the usual way. Through the bolt eye the loop head a coated with friction material thin metal sleeve 5 (Fig. 1) is inserted, the protruding Ends are flanged so that they rest against the sheet metal hood and can be soldered to it.

The isolator of Fig. 3 is preferably used in the following operations:

The GRP rod 1 is just as described above for the production of the insulator, FIG. 1, separately generated and wound.

Furthermore, according to FIG. 6, a foam ring is encased in a special casting mold in a separate operation with a flexible casting resin compound. This mold is in two parts, the parting line running in a radial plane. In the lower part 80 of the open casting mold according to the illustration, a cylinder 81 is fitted and sealed by means of an annular seal 82. Spacer bodies Qj, the foam ring 104 and further spacer bodies 8 'are placed one after the other in this casting mold part. The casting mold is then closed by placing the upper part 84 on it.

109845/1353

ORIGINAL INSPECTtCi

The upper part is sealed against the cylinder 8l by a close fit, and an additional ring seal 82 ^f. A filling channel 85 and an overflow channel 86 are recessed in the parting line. The closed casting mold is pivoted 90 clockwise from the position shown and is filled with a casting resin compound, which is flexible in the hardened state, through the channel 85 which is then located at the bottom. After hardening and demolding, the surface of the casting is roughened and preferably coated with an electrically weak or semiconducting lacquer.

According to 'Fig. 6 produced ring part 104, 103 is pulled onto the wound GPK rod while stretching. The resulting component is placed in a three-part mold 30, 31 * 32 according to FIG. 7. Each of these three molded parts has a parting line lying in the plane of the drawing. The GRP ^ rod is sealed by two sealing rings'33 and J> K. The mold is equipped with a filling opening 35 at the bottom and an overflow opening 36 at the top. It is filled from below with a cast resin compound that is flexible in the hardened state. After sufficient hardening of this casting resin mass, demolding, surface treatment of the casting and any application of an electrically weakly or semiconducting lacquer layer, the sheathing takes place according to FIG. 8.

The arrangement shown in FIG. 8 agrees

that of FIG. 5 essentially corresponds, the same

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the jacketing operation performed in this arrangement. In Figs. 8 and 5 corresponding parts are with provided with the same reference numerals.

Cycloaliphatic, anhydride-hardened with quartz mill and aluminum oxide trihydrate are preferably used to produce the jacket Filled resin-hardener systems are used. The webs are preferably made from a modified epoxy resin.

10984S / 1353

Claims (1)

Expectations 1. J · Preiluft high-voltage suspension insulator with a tensile core, in particular a fiberglass-plastic rod, and a weather-resistant hardened plastic jacket, in which core and jacket through at least a web made of compact flexible material are mechanically connected to one another, the web spaces are preferably filled with fine-pored, volume-expandable material, characterized in that from the web volume occupied or the sum of the volumes occupied by all webs is at most equal to the total volume of the web spaces, and that the web bsw. the webs are shaped and arranged in such a way that the compressibility of their entirety including spaces viewed macroscopically many times over, in particular * special by at least ten times that of the Web material is » 2. Isolator ¹ according to claim 1, characterized in that that in each i (Axial section) "ι Longitudinal section / the height of the webs grooved over the radial extent is equal to or less than the height of the web spaces averaged over the radial extent. 5 · Insulator according to claim 2, characterized in that that in each laid by the central axis of the isolator (Axial section)
Longitudinal section / the height of the webs averaged over the radial extent is equal to or smaller than the radial extent of the webs. 4. Insulator according to claim 1, characterized in that the webs are made of such a material and so are dimensioned and arranged so that the entirety of the webs and web spaces viewed macroscopically up to at a temperature that is equal to or greater than -40 C has the following three limit values: a.) Compressibility X * 5.10 "* V b.) maximum shear deformability T ___ - 50 $ Iu CLJv. c.) Secant shear modulus G ₀ - 0.1 kp / mm. 5. Insulator according to claim 1, characterized in that a single web surrounds the core in a helical manner, where the pitch of the helix is smaller at both ends than in the middle. 6. Insulator according to claim 1, characterized in that a single web surrounds the core in a helical manner, wherein the space running between this web, also in the form of a screw line, passes through at least once a wall-like part is interrupted, which consists of a 'same material as the web. 10984B / 1353 7. Insulator according to claim 1, characterized in that each web surrounds the core in a ring shape. 8. Insulator according to claim 7, characterized in that the mutual distances between the annular webs at the two jacket ends are narrower than in the central part. 9 ^% 'insulator according to one of the preceding claims, characterized in that the web or webs merge or merge into the core and / or jacket in the manner of a fillet. 10. Insulator according to one of the preceding claims, characterized in that the web spaces with foam rubber are filled out. 11. Insulator according to one of the preceding claims, characterized in that the inner surface of the jacket and \ Preferably the surface of the core is covered with a weakly or semiconducting layer, which is conductively connected to the insulator poles. 12. Insulator according to one of the preceding claims, characterized in that the fine-pored volume expandable Material is weakly or semiconducting and preferably conductively connected to the insulator poles. 109845/1353 13. Isolator according to one of the preceding claims, characterized in that the fine-pored volume expandable material with a weakly or semiconducting layer is coated, which is preferably conductively connected to the insulator poles. 14. Isolator according to one of the preceding claims, characterized in that at least one annular shell bulging out in the manner of an expansion membrane is inserted into the jacket, the bulge of which is for the most part filled with a fine-pored, volume-expandable material, which in turn is embedded in a compact flexible material. 15. Isolator according to claim 14, characterized in that that the ring shell and its filling are made of the same three materials as. the insulator jacket and the between this and the insulator core located components, 16. Insulator according to one of the preceding claims, characterized in that the two jacket ends by means of a metal hood bulging like an expansion membrane are tightly connected to the protruding core ends, wherein the hoods encapsulate the core ends. 17 · Method for producing the insulator according to claim 1, with a prefabricated core, in particular one Glass fiber-plastic rod, characterized in that a cavity-forming pressure 31e; T) ent or cavity-forming 1 0 S 8 4 5/1 3 5 3 Elements attached to the core that one with the cavity-forming Element or »the cavity-forming elements occupied core is positioned in a first casting mold and encapsulated with a first liquid casting resin compound, which is flexible in the hardened state, so that the so formed Composite body positioned in a second casting mold having the desired shell shape, and that one the one between this second mold and the composite body surface fills the gap left with a second liquid casting resin compound, which in the hardened state has optimal electrical surface properties. 18. The method according to claim IJ. characterized in that you have a cavity-forming element in his preferably length of elastically stretchable hose used and this / with Tension winds helically around the core. 19 method according to claim 17 characterized that they are elastically stretchable as cavity forming elements Preferably Söhlauchringe used whose inner ring diameter / smaller is than the core Durohesser, so these rings through their Internal stress can be fixed on the core. 20. The method according to claim l8 or 19. » characterized, that the hose or hoses are exposed to an electric extinguishing gas before it is attached to the core, such as sulfur hexafluoride fills and is sleeping. ! 09845/1363 21. The method according to claim 17 »characterized in that that as a cavity-forming element one in his compressible length elastically stretchable profile made of fine-pored / material, preferably especially foam rubber used, and this / with tension winds helically around the core. 22. The method according to claim 17, characterized in that the cavity-forming elements are elastically stretchable compressible bare profile rings made of fine-pored / material, in particular Preferably, foam rubber is used, the inner ring diameter of which is smaller than the core diameter, so that these rings can be fixed to the core by their internal stress. 2Y. A method according to any one of claims 17 to 22, characterized in that the cavity-forming element or the cavity-forming elements before its or their attachment to the core with a lacquer of low electrical conductivity, in particular coated with a semiconductor lacquer. 24. The method according to any one of claims 17 to 23, characterized in that the core is prior to application of the cavity-forming elements with a lacquer of low electrical conductivity, in particular with coated with a semiconductor lacquer. 25. The method according to any one of claims 17 to 24, characterized in that the in the first mold 109845/1353 formed composite body in front of sonar sheathing in the second Casting mold with a lacquer of low electrical conductivity, in particular coated with a semiconductor lacquer. 26. The method according to claim 17, characterized in that that one uses cavity-forming elements, which are made of an electric extinguishing gas, e.g. sulfur hexafluoride (SF, -). Foamed material. 10 9 8 4 5/1 353 Blank page