US3878321A - High voltage electric insulator termination constructions - Google Patents

High voltage electric insulator termination constructions Download PDF

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Publication number
US3878321A
US3878321A US437028A US43702874A US3878321A US 3878321 A US3878321 A US 3878321A US 437028 A US437028 A US 437028A US 43702874 A US43702874 A US 43702874A US 3878321 A US3878321 A US 3878321A
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United States
Prior art keywords
nose
spigot
nose ring
construction according
ring
Prior art date
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Expired - Lifetime
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US437028A
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English (en)
Inventor
Richard Anthony Ely
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.)
Transmission Developments Ltd
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Transmission Developments Ltd
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Filing date
Publication date
Application filed by Transmission Developments Ltd filed Critical Transmission Developments Ltd
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Publication of US3878321A publication Critical patent/US3878321A/en
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    • 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
    • H01B17/42—Means for obtaining improved distribution of voltage; Protection against arc discharges

Definitions

  • An end-fitting electrode for a high voltage insulator has a nose spigot and outside this spigot is positioned an electrically conductive nose ring which is flexibly and electrically connected with the spigot so that mechanical stresses in the insulation material of the insulator are kept low in the region of the nose ring outer surface which is where the electrical interface occurs.
  • the nose ring may be a rigid conductive material which is interconnected with the nose spigot by a flexible sealing material.
  • An electrically conductive screen may be embedded in the insulating material surrounding the nose ring and nose spigot combination to provide for electrical stress relief.
  • insulators Other conductors that can be directly or indirectly supported by such insulators are. for example. bus-bars and the overhead contact wires of railway electrification systems wherein the insulators may, for example, be used as steady arms.
  • the insulators may also form insulated bushings or insulator posts.
  • the insulator body is provided with one or more high strength rigid core members formed, for example, from resin-bonded fibrous material.
  • core(s) are attached to the ends of the core(s) to the ends of the core(s) to the ends of the core(s) and the end-fitting.
  • the resinous insulating material is then cast or moulded about the core(s) and fills the space between the core(s) and the end-fitting.
  • the open end of the end-fitting is provided with a curved surface, forming a nose spigot, and the resin is moulded around the nose spigot so that good surface contact or adhesion is achieved between the insulating resin and the nose spigot. the curved surface of which forms the electrical interface between the electrode and the insulating resin.
  • this invention provides a termination construction for high voltage electric insulators comprising an end-fitting electrode having a nose spigot provided with an electrically conductive nose ring which is flexibly and electrically connected with the nose spigot onto which the insulating material for the insulator may be bonded, and which will provide the electrical interface.
  • the flexible interconnection between the nose spigot and nose ring allows relative movement there-between so as to alleviate the mechanical stresses which may occur in the insulating material forming an insulator provided with the termination constructions of this invention.
  • the nose ring is constructed from metal or other rigid conductive material, such as a metal-powder filled resin.
  • a flexible sealing material can be a solid or foamed elastomer, e.g., rubber or a silicone rubber LII foam.
  • the sealing material is so formed that a part thereof which will be subjected substantially only to shear stresses is a solid material and the remainder of the sealing material is a closed-cell foam-type material.
  • the sealing material may be bonded to the nose spigot and nose ring by an adhesive bonding rubber curable at room temperature or at elevated temperatures.
  • the nose spigot and nose ring are electrically interconnected by a metal strip, such as a stranded wire in a protective sheath, so as to eliminate leakage current from the sealing material.
  • a metal strip such as a stranded wire in a protective sheath
  • electrically conductive screen is electrically interconnected with the nose spigot and nose ring and is provided as a screen over the electrical interfaces of the nose spigot and the outer surface of the nose ring.
  • This screen may be a metal gauze stress shield.
  • the invention also extends to complete high voltage insulators comprising a body of insulating material such as an epoxy resin or any other insulating polymeric material. with the termination construction of the invention bonded to the end thereof. The electrical interface between the end-fitting electrode and the insulation material will occur in the region of the outer face of the nose ring.
  • FIG. 1 is a partly vertically sectional side elevation showing the end of an insulator provided with one preferred arrangement ofa termination construction in accordance with the invention, incorporating a metal nose ring. and separate elastomeric seals;
  • FIG. 2 is a side view of a complete insulator incorporating an assembly as shown in FIG 1.
  • FIG. 1 there is shown a galvanised cast iron or aluminium end-fitting electrode 1 into which has been embedded, by casting or moulding, a body 2 of insulating resin.
  • the resin body 2 is formed about a central tensile core 16, formed, for example from resin bonded glass fibre.
  • a nose ring 4 embedded in the resin body 2, below the first shed 3 thereof, is a nose ring 4 formed from a similar metal (or other rigid conductive material, such as a resin filled with metal powder), and spaced from the nose spigot 5 of the end fitting l by a body of flexible material 6 providing a weatherproof seal and possibly also having electrical ifl sulating properties.
  • Rivetted to the nose ring 4 and nose spigot 5, so that they are electrically interconnected is a tinned copper stranded wire 7 protected by an elastomeric sheath, such as a silicone sheath.
  • an elastomeric sheath such as a silicone sheath.
  • the curved surface 4A of the nose ring provides the electrical interface between the end-fitting electrode 1 and the insulating resin body 2.
  • the wire 7 accommodates leakage currents, and eliminates electrical leakage across the seal 6 which could result in seal degradation.
  • a copper or brass gauze or mesh stress shield 8 may be provided to minimise any problems of internal discharge.
  • This stress shield 8 is rivetted by rivets 9 to the nose ring 4 (and preferably also to the endfitting electrode 1) and is embedded in the resin body 2.
  • the shield 8 now provides the electrical front so that there is no electrical stress in the areas behind it and voids will not cause discharge problems.
  • the particular shape of the nose ring 4 shown in the drawing substantially protectsthe nose spigot area and the. insulating body 6 so that the gauze shield 8 may not be necessary.
  • the nose ring 4 is suitably contoured to give good electrical stress distribution the relatively large external diameter of the nose ring facilitates natural cleaning and provides a relatively large surface to transmit leakage current to the surface of the resin.
  • the flexible insulating body 6 is illustrated as having a solid rubber section 6A and a silicone rubber foam section 68.
  • the resin body 2 is bonded to the cylindrical surface 2A of the core and also to the nose ring, the surface 4A of which may be regarded as a planar surface which is mutually perpendicular to the cylindrical core surface 2A.
  • the mutually perpendicular surfaces 2A of a foam-like material If desired, the whole of the insulating body 6 could be formed from a closed-cell foam-like material the essential characteristic is that the body 6 should have sufficient flexibility whilst offering minimal mechanical resistance. Ideally. the material will also be suitable for long term outdoor exposure.
  • the termination construction shown in FIG. 1 is particularly suited for use in crossarm (or cantilever) insulators where the mechanical stresses in the insulating resinbody are produced not only by shrinkage due to cooling. but also by bending forces applied to the insulator body which will vary around the circumference of the .body.
  • the flexible connection between the endfitting electrode and the insulator body allows the combination of tensile and compressive stresses in the insulation body to be alleviated, thus significantly reducing the possibilities of rupturing of the insulation.
  • FIG. 2 The complete insulation assembly is indicated in FIG 2.
  • An end-fitting electrode 1 is secured to both ends of thetensile core 16 by pins 17 and the nose spigot of each electrode is provided with a nose ring assembly 18 (diagramatically illustrated).
  • integrally cast about the core 16 and within the electrode I is the resinous insulating body 2 formed with the sheds 3 as indicated. if desired.
  • a stress flange 19 may be provided on each electrode 1 for protection of the nose ring assemblies 18 from damage should flashover occur.
  • a termination construction for high voltage electric insulators comprising a hollow end-fitting electrode providing an open end for receipt of a tensile core and having a nose spigot at said open end forming an outer surface.
  • an electrically conductive nose ring formed from a rigid conductive material, the nose ring having an inner surface which faces said outer surface of the nose spigot.
  • a flexible sealing material bonding said inner and outer surfaces together, means electrically interconnecting the nose ring with the nose spigot, and a surface of the nose ring, remote from the nose spigot, providing an area onto which the insulating material for the insulator may be bonded, and which will provide the electrical interface.
  • sealing material is an elastomer, selected from the group consisting of solid rubber, foamed natural rubber and a silicone rubber foam.
  • sealing material is formed in two parts each comprising elastomer. wherein the one part, which will. during use in an insulator, be subjected substantially only to shear stresses is a solid material and the other part of the sealing material is a closed-cell foam-type material.
  • an 'electrically conductive screen is electrically interconnected with the nose spigot and nose ring and is provided as a screen over the electrical interfaces. of the nose spigot and the outer surface of the nose ring.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Insulators (AREA)
US437028A 1973-02-17 1974-01-28 High voltage electric insulator termination constructions Expired - Lifetime US3878321A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB789473*[A GB1451071A (en) 1973-02-17 1973-02-17 High voltage electric insulator termination constructions

Publications (1)

Publication Number Publication Date
US3878321A true US3878321A (en) 1975-04-15

Family

ID=9841860

Family Applications (1)

Application Number Title Priority Date Filing Date
US437028A Expired - Lifetime US3878321A (en) 1973-02-17 1974-01-28 High voltage electric insulator termination constructions

Country Status (9)

Country Link
US (1) US3878321A (enrdf_load_stackoverflow)
JP (1) JPS49114091A (enrdf_load_stackoverflow)
BR (1) BR7400767A (enrdf_load_stackoverflow)
CA (1) CA1011418A (enrdf_load_stackoverflow)
CH (1) CH583452A5 (enrdf_load_stackoverflow)
DE (1) DE2406617A1 (enrdf_load_stackoverflow)
FR (1) FR2218626B3 (enrdf_load_stackoverflow)
GB (1) GB1451071A (enrdf_load_stackoverflow)
IT (1) IT1004868B (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4355200A (en) * 1980-10-27 1982-10-19 Interpace Corporation Polymer rod insulator with improved radio noise and corona characteristics
US4835341A (en) * 1988-03-08 1989-05-30 Maxwell Laboratories, Inc. Electrical insulator for use in plasma environment
US5374780A (en) * 1992-09-02 1994-12-20 Maclean Fogg Company Composite insulator structure and method of construction
US5406033A (en) * 1992-09-02 1995-04-11 Maclean-Fogg Company Insulator structure and method of construction
USD375079S (en) 1995-02-21 1996-10-29 Maclean-Fogg Company Power line insulator
US6501029B1 (en) 1999-12-03 2002-12-31 Electro Composites, Inc. High-voltage homogeneous co-curing composite insulator
US11227708B2 (en) * 2019-07-25 2022-01-18 Marmon Utility Llc Moisture seal for high voltage insulator

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58178916A (ja) * 1982-04-12 1983-10-20 ラップ・インシュレイター・カンパニー 高圧用碍子
DE3214141A1 (de) * 1982-04-14 1983-10-20 Interpace Corp., Parsippany, N.J. Polymer-stabisolator mit verbesserten stoerfeld- und corona-charakteristiken
FR2590398B1 (fr) * 1985-11-15 1988-09-09 Ceraver Dispositif de protection d'un capot d'isolateur electrique de suspension contre la corrosion
ES2787511T3 (es) * 2010-05-28 2020-10-16 Lapp Insulator Gmbh Aislante compuesto

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2023808A (en) * 1933-02-16 1935-12-10 Locke Insulator Corp Shielded cemented type insulator
US3318995A (en) * 1966-04-25 1967-05-09 Westinghouse Electric Corp Cast electrical bushing construction having controlled and shielded shrinkage voids
US3328515A (en) * 1965-08-24 1967-06-27 Gen Electric Polymeric insulator with means for preventing burning due to leakage current and arcs

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2023808A (en) * 1933-02-16 1935-12-10 Locke Insulator Corp Shielded cemented type insulator
US3328515A (en) * 1965-08-24 1967-06-27 Gen Electric Polymeric insulator with means for preventing burning due to leakage current and arcs
US3318995A (en) * 1966-04-25 1967-05-09 Westinghouse Electric Corp Cast electrical bushing construction having controlled and shielded shrinkage voids

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4355200A (en) * 1980-10-27 1982-10-19 Interpace Corporation Polymer rod insulator with improved radio noise and corona characteristics
US4835341A (en) * 1988-03-08 1989-05-30 Maxwell Laboratories, Inc. Electrical insulator for use in plasma environment
US5374780A (en) * 1992-09-02 1994-12-20 Maclean Fogg Company Composite insulator structure and method of construction
US5406033A (en) * 1992-09-02 1995-04-11 Maclean-Fogg Company Insulator structure and method of construction
USD375079S (en) 1995-02-21 1996-10-29 Maclean-Fogg Company Power line insulator
US6501029B1 (en) 1999-12-03 2002-12-31 Electro Composites, Inc. High-voltage homogeneous co-curing composite insulator
US11227708B2 (en) * 2019-07-25 2022-01-18 Marmon Utility Llc Moisture seal for high voltage insulator

Also Published As

Publication number Publication date
FR2218626A1 (enrdf_load_stackoverflow) 1974-09-13
DE2406617A1 (de) 1974-09-05
CA1011418A (en) 1977-05-31
GB1451071A (en) 1976-09-29
BR7400767D0 (pt) 1974-09-10
FR2218626B3 (enrdf_load_stackoverflow) 1976-11-26
BR7400767A (pt) 1975-10-07
JPS49114091A (enrdf_load_stackoverflow) 1974-10-31
IT1004868B (it) 1976-07-20
CH583452A5 (enrdf_load_stackoverflow) 1976-12-31

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