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
  • H01B17/32—Single insulators consisting of two or more dissimilar insulating bodies
• • 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
  • H01B3/02—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances
  • H01B3/08—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances quartz; glass; glass wool; slag wool; vitreous enamels
  • H01B3/087—Chemical composition of glass

Definitions

• the invention relates to a composite insulator made of plastic, in particular for high-voltage overhead lines, consisting of a glass fiber reinforced plastic rod, plastic shield arranged on the rod and fittings on the rod ends.
• Such composite insulators, the z. B. are known from DE-OS 26 50 363, certain electrical requirements should meet.
• the rod should be resistant to electrical breakdown.
• the screens should be attached to the rod, which is also called a trunk, in such a way that no electrical breakdowns occur in the contact area.
• the screens themselves should be dimensioned so thick that electrical breakdowns are avoided; They should also consist of a weather, UV and ozone resistant material that has a very high tracking resistance.
• the glass fiber reinforced plastic rod In addition to the electrical strength, the glass fiber reinforced plastic rod must ensure considerable mechanical strength.
• the mechanical strength results from the material composition, the type and location of the fibers and from the bond between glass fibers and plastic.
• breaks have occurred in particular in the case of overhead line composite insulators, which were initially inexplicable and occurred after a relatively short operating time with relatively low mechanical loads.
• the fracture patterns of the insulators broken in overhead lines differ optically from fracture patterns which, for. B. in train try to occur in the laboratory and also in long-term long-term strength tests in open-air test fields; Because a plastic rod reinforced axially parallel with endless glass fibers breaks under mechanical stress by the binding resin detaching from the glass fibers and tearing the glass fibers. The rod splinters in the longitudinal direction.
• the fractures occurring in situ run almost perpendicular to the longitudinal axis of the bar, the fracture surface being smooth.
• the object of the invention is to prevent the transverse fractures occurring in situ in composite insulators of the type described in the introduction.
• a composite insulator made of art fabric consisting of a glass fiber reinforced plastic rod, arranged on the rod plastic screens and fittings on the rod ends, solved in that the axially parallel glass fibers in the plastic rod consist of low-boron, preferably boron-free aluminum silicate glass.
• a low-boron glass is understood to be a glass which contains boron or a boron compound, calculated as B 2 O 3 , of at most one% by weight.
• Boron-free glasses are glasses which have boron or boron compounds, calculated as B 2 O 3 , of less than 0.01% by weight because lower boron contents can only be determined by trace analysis and are ineffective for the purpose according to the invention.
• Glass fibers made from a glass of the following composition are particularly favorable:
• Glass fibers of a glass having the following composition are preferred:
• Na 2 O - Glass fibers without CaO are particularly resistant and are therefore preferred.
• the glass fibers should expediently be processed with a thickness of 5 to 4.0 ⁇ m and in an endless length parallel to the axis of the rod.
• the alkali oxide content of the glass is less than 1% by weight.
• the glass fibers should preferably be alkali-free. As is known, this can prevent the water attack or increase the dielectric strength.
• a binder resin which is resistant to water attack is used as the binder resin surrounding the glass fibers. It is therefore preferable to use a binder resin that has no hydrolyzable molecules.
• An epoxy resin of the glycidyl ether type is particularly suitable in this respect.
• the insulator according to the invention In order to be able to manufacture the insulator according to the invention as economically as possible, it is expedient to use prefabricated insulating parts for the shield cover. In this way, isolators of any length can be produced; because the glass fiber reinforced plastic rod can also B. be produced in an endless drawing process. Rod surface and screens can be treated in a known manner with adhesives and - as usual - put together, for. B. by pouring, vulcanizing, gluing or the like. The radial connection joints between the screen parts no longer play a dominant role, since the glass fiber reinforced plastic rod is resistant to nitric acid and water.
• Fig. 1 shows schematically the experimental arrangement for
• FIG. 2 shows a diagram of a test result
• FIG. 3 shows an isolator according to the invention.
• the test specimen shown in Fig. 1 consists of a glass fiber reinforced plastic rod 1 and the suspension fittings 2, to which a tensile force Z can be applied.
• an acid reservoir 3 On the free length of the rod there is an acid reservoir 3 which, for. B. can be a cut open polyethylene bottle, which is pushed onto the rod and sealed with insulating tape.
• FIG. 2 shows a functional relationship between tensile force Z and the breaking time of the test specimen according to FIG. 1.
• Line 4 indicates the tensile force / time relationship (time that passes until a rod breaks) of a glass-fiber reinforced plastic rod which has no acid effect is exposed.
• Line 5 illustrates the traction / time relationship when an HNO 3 (approximately 6.5% nitric acid) is filled into the acid reservoir 3 and glass fibers with a boron content are contained in the glass fiber reinforced plastic rod calculated as B 2 O 3 is between 2 and 6%.
• the break / time behavior of a glass fiber reinforced plastic rod, the glass fibers of which do not contain boron, is shown by line 6.
• the diagram in FIG. 2 thus represents the break time difference between the glass fiber reinforced plastic rods of the previous composition (boron-containing glass) and those according to the invention ( boron-free glass).
• Fig. 3 shows the composite insulator according to the invention. It consists of a glass fiber reinforced plastic rod 7, which consists of an epoxy resin of the glycidyl ether type and glass fibers of axially parallel endless fibers, which has a boron content, calculated as B 2 O 3 , of less than 0, 01% and an alkali content, calculated as Na 2 O, of less than 1%.
• the insulator also consists of a shield cover made of individual prefabricated shields 8, which on the Slid on the rod and with it mechanically and electrically firmly connected.
• Metallic suspension fittings S are also provided, which are attached to the ends of the composite insulator. This connection between rod 7 and armature 9 can be produced by known techniques such as wedging or pressing the rod.
• shield cover Depending on the type of material of the shield cover, however, it can also be advantageous to prefabricate the shield cover and apply it in one operation.
• Other materials for shielding sleeves can also require a complete encapsulation, pressing, extrusion or overmolding of the shielding sleeve in a one or more part form as the most economical solution.
• silicone elastomers for the shield cover, which have already proven their worth as insulator materials.
• ethylene-propylene-based elastomers can also be suitable as a screen material.
• Other shielding materials such as cycloaliphatic epoxy resins or polytetrafluoroethylene can also be suitably used in the insulator according to the invention.

Landscapes

• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Insulators (AREA)
• Insulating Bodies (AREA)
• Organic Insulating Materials (AREA)

Priority Applications (8)

Applications Claiming Priority (1)

Publications (1)

Family

ID=8164829

Family Applications (1)

Country Status (7)

Cited By (3)

Families Citing this family (1)

Citations (3)

• 1981
  • 1981-11-04 AU AU7892482A patent/AU7892482A/xx active Pending
  • 1981-11-04 EP EP81903257A patent/EP0092548B1/de not_active Expired
  • 1981-11-04 DE DE8181903257T patent/DE3172780D1/de not_active Expired
  • 1981-11-04 JP JP50366581A patent/JPS58501528A/ja active Granted
  • 1981-11-04 WO PCT/EP1981/000175 patent/WO1983001707A1/en active IP Right Grant
• 1982
  • 1982-11-04 ZA ZA828103A patent/ZA828103B/xx unknown
  • 1982-11-04 CA CA000414888A patent/CA1212436A/en not_active Expired

Patent Citations (3)

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