CA1266898A - High voltage externally-separable bushing - Google Patents
High voltage externally-separable bushingInfo
- Publication number
- CA1266898A CA1266898A CA000526655A CA526655A CA1266898A CA 1266898 A CA1266898 A CA 1266898A CA 000526655 A CA000526655 A CA 000526655A CA 526655 A CA526655 A CA 526655A CA 1266898 A CA1266898 A CA 1266898A
- Authority
- CA
- Canada
- Prior art keywords
- conductor
- enclosure
- bushing
- sleeve part
- sleeve
- 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.)
- Expired - Lifetime
Links
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
- H01B17/26—Lead-in insulators; Lead-through insulators
- H01B17/265—Fastening of insulators to support
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
- H01R13/46—Bases; Cases
- H01R13/53—Bases or cases for heavy duty; Bases or cases for high voltage with means for preventing corona or arcing
Abstract
Abstract of the Disclosure A bushing, having an elongated conductor substantially encased in insulating material, which extends in sealing relationship through an aperture in a sealed enclosure encasing an electrical apparatus, comprising a conductor having two parts, a first generally cylindrical rod part which is permanently fixed at its proximal end to the electrical apparatus and which extends therefrom toward the aperture, and a second sleeve part having a generally annular passage disposed to circumferentially engage substantially all of the first rod part and thereby provide a conductive path therebetween; a one-piece insulator permanently attached to and substantially encasing the sleeve part of the conductor; means for threadably connecting the two parts of the conductor such that connection and disconnection can be accomplished from outside the enclosure, thereby enabling disconnection of the sleeve part and the insulator from the electrical apparatus without opening the enclosure;
and means for sealing the junction of the two parts of the conductor so as to contain the environment within the enclosure.
and means for sealing the junction of the two parts of the conductor so as to contain the environment within the enclosure.
Description
Technical Field The present invention relates generally to electrical bushings, and, more particularly, to an externally-separable bushing for use with high voltage equipment.
Background Art High voltage equipment is commonly sealed within a welded enclosure. The seal is required because the enclosure contains either a gaseous (e.g., SF6) or liquid (e.g., oil) dielectric atmosphere within which the equipment operates.
To enable connection between the enclosed equipment and external power lines, a bushing is used to provide a conductor through the wall of the enclosure while simultaneously insulating the conductor from the enclosure and maintaining the seal.
Bushings typically consist of a unitary metal conductor encapsulated in epoxy insulation.
The inside end of the bushing (i.e., the proximal end of the conductor) is usually connected rigidly (e.g., by a metallic clamp and hardware) to the enclosed high voltage equipment, while the outside end of the bushing is designed to matingly receive a connector device, such as an elbow connector. The outside end of the bushing (i.e., the insulator body and/or the bushing-to-elbow interface) is subject to damage during both transportation and use which quite often renders the bushing unusable. In this event, the bushing must be replaced, which for a unitary bushing requires opening of the sealed enclosure and disconnection of the bushing from the high voltage equipment. Such replacement procedures are costly, time-consuming and often quite difficult to perform, 53-110/kah especlally when the equlpment Is located In the close quarters of an underground vault.
The present Inventlon provldes an Improved hlgh voltage bushlng whlch, If damaged, can be externally separated from elec-trlcal equlpment sealed wlthln an enclosure.
The present Inventlon also provldes such an Improved hlgh voltage bushlng havlng two threadably connected conduc~or parts, the flrst of whlch Is permanently connected to electrlcal equlpment sealed wlthln an enclosure, and the second of whlch Is externally detachable detachable from the flrst part.
The present Inventlon agaln provldes a hlgh voltage bushlng whlch may be qulckly, and therefore Inexpenslvely, sepa-rated from electrlcal equlpment sealed wlthln an enclosure.
Accordlng to the present Inventlon a bushlng, havlng an elongated conductor substantlally encased In Insulatlng materlal, whlch extends In sealIng relatlonshlp through an aperture In a sealed enclosure encaslng an electrlcal apparatus, comprlslng:
sald conductor havlng two parts, a flrst generally cyllndrIcal rod part whlch Is fIxed at Its proxlmal end of the electrlcal apparatus and whlch extends therefrom toward the aperture, and a second sleeve part havlng a generally annular passage dlsposed to clrcumferentlally engage the flrst rod part and thereby provlde a conductlve path therebetween; a one-plece Insulator seallngly attached to and substantlally encaslng the sleeve part of the conductor; means for threadably connectlng the two parts of the conductor such that connectlon and dlsconnectlon can be accom-pllshed from outslde the enclosure, thereby enabllng dlsconnec-tlon of the sleeve part and the one-plece Insulator from the electrlcal apparatus wlthout dlsmantllng the enclosure, sald con-nectlng means comprlslng a screw, a clrcumferentlal shoulder wlthln the passage of the sleeve part of the conductor for seat-Ing a head of the screw, and a threaded bore In a dlstal end of the rod part of the conductor for recelvlng a threaded end of the screw; and means for sealIng the Junctlon of the two parts of the conductor so as to malntaln the envlronment wlthln the enclosure.
Sultably the bushlng further comprlses conductlve sprlng means dlsposed wlthln the passage of the sleeve Part of the conductor between and contlguous wlth the clrcumferentlal shoulder and a dlstal end of the rod part of the conductor. Deslrably the seal-Ing means comprIses at least one reslllent 0-rIng dlsposed In a clrcumferentlal channel located along the passage of the sleeve part of the conductor. Preferably the sealIng means further com-prlses a reslllent 0-rlng dlsposed wlthln the passage of the sleeve part of the conductor between and contlguous wlth the clr-cumferentlal shoulder and a dlstal end of the rod Part of the conductor. Sultably the conductor further comprlses an enlarged generally frustoconlcal surface of the rod part of the conductor dlsposed wlth a base portlon toward a proxImal end of the rod part, and an enlarged generally frustoconlcal complementary bore In the sleeve part of the conductor.
In accordance wlth the present Inventlon, there Is pro-vlded a bushlng, havlng an elongated conductor substantlally encased In Insulatlng materlal, whlch extends In seallng rela-tlonshlp through an aperture In a sealed enclosure encaslng an electrlcal apparatus, comprlslng a conductor havlng two parts, a flrst generally cyllndrIcal rod part whlch Is permanently fIxed at Its proxlmal end to the electrlcal apparatus and whlch extends therefrom towards the aperture, and a second sleeve part havlng a ~enerally annular passage dlsposed to clrcumferentlally engage substantlally all of the fIrst rod part and thereby provlde a conductlve path therebetween; a one-plece Insulator seallngly attached to and substantlally encaslng the sleeve part of the conductor; means for threadably connectlng the two parts of the conductor such that connectlon and dlsconnectlon can be accom-pllshed from outslde the enclosure, thereby enabllng dlsconnec-tlon of the sleeve part and the Insulator from the electrlcalapparatus wlthout openlng the enclosure; and means for seallng i<~h the Junctlon of the two parts of the conductor so as to contaln the envlronment wlthln the enclosure.
In a partlcular aspect thereof the present Inventlon provldes a conductlng bushlng for provldlng a hlgh voltage carry-lng connectlon from the outslde to the Inslde of a sealed enclo-sure comprlslng, In comblnatlon: a one-plece Insulator body formed to be fItted through an aperture In an enclosure and to be sealed agalnst an outer wall of the enclosure; a two-plece con-ductlve connector passlng through the Insulator body and formedof a sleeve surroundlng a rod, one plece of sald connector belng adapted to be flxed to an electrlcal devlce wlthln the enclosure and the other plece of the connector belng sealed to sald Insula-tor body, sald connector pleces havlng matlng surfaces adapted to wedge together to form a good electrlcal connectlon when the rod Is drawn Into the sleeve; and means for releasably drawlng the rod Into the sleeve operable from an end of the Insulator body that It outslde the enclosure, whereby the means can be released and the entlre Insulator body and the connector part sealed thereto can be removed and replaced from outslde of the enclo-sure, sald means comprlslng a screw, a clrcumferentlal shoulder wlthln the sleeve for seatlng a head of the screw, and a threaded bore In a dlstal end of the rod for recelvlng a threaded end of the screw.
The present Inventlon wlll be further Illustrated by way of the accompanylng drawlngs, In whlch:-Flgure 1 Is a perspectlve vlew showlng a vault-style swltch equlpped wlth the hlgh voltage externally separable bush-lng of the present Inventlon;
Flgure 2 Is a sectlonal slde plan vlew of a flrst embodIment of the Inventlve bushlng;
Flgure 3 Is a sectlonal slde plan vlew of a second - 3a -~t~
embodIment of the Inventlve bushlng; and Flgures 4a and 4b are perspectlve vlew and a sectlonal slde vlew, respectlvely, of a dlsc sprlng.
Turning now to the drawlngs and referrlng fIrst to Flg.
1, there Is shown a hlgh voltage, vault-style -- 3b -' switch 10 designed for load interrupting switching, sectionalizing, testing or grounding of underground cable systems through 38kV. In a vault-style switch, the high voltage electric equipment is encased within a welded steel tank 11, which is hermetically sealed and fully submersible. A handle 12 is used for operating the enclosed switching equipment, and the operation of the switching equipment can be viewed through windows 13 in the side wall of the steel tank 11. Typically, the sealed steel tank 11 contains either a gaseous ~e.g., SP6) or liquid (e.q., oil) dielectric atmosphere within which the high voltage switching equipment operates. Bushings 14, held by brackets 15 in apertures through the side wall of the steel tank 11, are used to provide a conductive path through the wall of the enclosure, thereby enabling connection between the enclosed switching equipment and external power distribution lines, while simultaneously insulating the conductive path from the enclosure and maintaining the enclosure's seal.
These bushings typically have an operating range rating of 7~ to 38 kV.
Considering now FIGS. 2 and 3, there is shown a bushing 14 embodying the present invention which is positioned in an aperture 16 in the side wall of the steel tank 11, and is maintained therein by means of a bracket 15, weld-in studs 17a, and nuts 17b.
In accordance with an important aspect of the present invention, the bushing 14 comprises a conductor having two parts, a first generally cylindrical rod part which is permanently fixed at its proximal end to the electrical apparatus and which extends therefrom towards the aperture 16, and a second sleeve part having a generally annular passage disposed to circumferentially engage 53-110/kah , ' ' ' 1 ~ti~ 8~
substantially all of the first rod part and thereby provide a conductive path therebetween, a one-piece insulator sealingly attached to and substantially encasing the sleeve part of the conductor, and means for threadably connecting the two parts of the conductor such that connection and disconnection can be accomplished from outside the tank 11, thereby enabling disconnection of the sleeve part and the insulator from the electrical apparatus without opening the tank.
Referring to the embodiment of FIG. 2, it will be seen that the bushing 14 comprises a conductor having a first generally cylindrical rod part 1~ and a second sleeve part 19, each of which is made of conductive metal such as copper or aluminum. The sleeve part 19 of the conductor has a generally annular passage 20 disposed to slidably engage substantially all of the rod part 18, and thereby provide a conductive path therebetween.
The distal end of the rod part of the conductor has an axial threaded bore 21 for receiving the threaded end of a screw 22, such as a cap screw. The head of the screw 22 is seated on a circumferential shoulder 23 located within the passage 20 of the sleeve part 19 of the conductor, and thus the screw 22 serves to threadably connect the rod 18 and sleeve 19 parts of the conductor. The head of the screw 22 can be accessed through the exterior opening 24 of the sleeve part of the conductor by means of a screwdriver, Allen wrench, or other such tool, thereby enabling turning of the screw, and consequently, external connection/disconnection of the two parts of the conductor. The portion 20' of the annular passage 20 between the exterior opening 24 and the circumferential shoulder 23 is threaded so 53-110/kah 1~;6~'3~
that a threaded interfacing rod ~not shown) made of conductive material can be threadably connected therein. This interfacing rod allows electrical connection between the sleeve part 19 of the conductor and an external connector device (not shown), such as an elbow connector.
In order to enhance the electrical interface and improve the seal between the rod part 18 and the sleeve part 19 of the conductor, the conductor can be designed to comprise an enlarged generally frusto-conical surface 25 on the rod part 18, disposed with its base towards the proximal end 31 of the rod part, and an enlarged generally frusto-conical complementary bore 26 in the passage 20 of the sleeve part l9. Thus, when the rod and sleeve parts of the conductor are threadably connected by means of the screw 22, the frusto-conical surface 25 of the rod part and the frusto-conical bore 26 of the sleeve part matingly engage one another, and thereby improve the conductive path between the two conductor parts.
A one-piece insulator body 27, comprised of high grade epoxy insulation material, is permanently attached (i.e., sealed) to, and substantially encases, the outer surface of the sleeve part 19 of the conductor, thereby isolating the conductor from the walls of the steel enclosure 11. The portion 27' of the insulator body 27 which, in use, extends exterior to the steel enclosure 11 has a generally frusto-conical shape, and thus, can be readily connected to various well-known connection devices, such as elbow connectors. Moreover, the exterior portion 27' of the insulator body 27 has a pair of integral annular collars 28, 29 which are engaged by the bracket 15 to maintain the bushing in the aperture 16 in the wall of the metal enclosure 11.
53-110/kah .
If desired, a gasket 30 can be located between the collar 29 and the wall of the metal enclosure 11 to seal the junction therebetween.
In use, the proximal end 31 of the rod part 18 of the conductor, which may, among other confiyurations, be flattened (as shown in FIG. 2) or threaded ~as shown in FIG. 3), is permanently attached to the electrical equipment ~not shown) encased within the steel enclosure 11. The distal end of the rod part 18 of the conductor extends toward the aperture 16 in the wall of the enclosure 11, and the sleeve part 19 of the conductor slidably engages substantially all of the rod part, thereby providing a conductive path therebetween. To seal the junction between the two parts 18, 19 of the conductor, and thereby maintain the gaseous or liquid environment within the enclosure 11, a resilient O-ring 32 is disposed in a circumferential channel 33 located along the passage 20 of the sleeve part 19 of the conductor. As shown in FIG. 2, this circumferential channel 33 can be located in the enlarged bore 26 in the passage 20. To further enhance the seal between the two parts of the conductor, a resilient O-ring 34 may be disposed within the passage 20 between, and contiguous with, the circumferential shoulder 23 and the distal end of the rod part 18 of the conductor.
It should be noted that in situations where the enhanced sealing provided by the second O-ring 34 is not necessary, conductive spring means (such as one or more of the disc springs 40 shown in FIGS. 4a and 4b) can replace the O-ring 34 and thereby serve to enhance the conductive path between the two parts of the conductor. Disc springs made of copper-beryllium are particularly suitable for this purpose.
53-110/kah ~2~;68~3~
The portions of the bushing 14 which, in use, lie exterior to the steel enclosure 11, are subject to damage which may render the bushing unusable.
Specifically, the exterior portion 27' of the insulator body 27 is subject to cracking and/or chipping during transportation and use, and the exterior end of the sleeve part 19 of the conductor, including its threaded annular passage 20', is subject to damage such as cross-threading and melting under short circuit conditions if the associated connector device is not properly secured. The present invention enables disconnection and replacement of the sleeve part 19 of the conductor and the entire insulator body 27, while leaving the rod part 18 of the conductor attached to the electrical equipment encased within the steel enclosure 11. Thus, the steel enclosure 11 need not be cut open, making the bushing replacement procedure quick and inexpensive.
FIG. 3 shows an alternate embodiment of the inventive bushing having an insulator body 27 identical to the insulator body of the embodiment shown in FIG. 2, but which has a modified two-part conductor. Specifically, the conductor of the embodiment shown in FIG. 3 comprises a generally cylindrical conductive rod part 35 and a conductive sleeve part 36 having a generally annular passage 37 disposed to circumferentially engage substantially all of the rod part and thereby provide a conductive path therebetween. The exterior surface of the rod part 35 and the surface of the annular passage 37 of the sleeve part 36 are complementarily threaded so that the two parts of the conductor can be threadably engaged. Thus, the entire insulator body 27, and the sleeve part 36 of conductor permanently affixed 53-110/kah i .
thereto, can be externally disconnected from the rod part 35 of the conductor and removed from the aperture 16 in the wall of the steel enclosure 11 by simply removing the bracket 15 and rotating the insulator body 27.
As with the embodiment shown in FIG. 2, the two parts 35, 36 of the conductor shown in FIG. 3 are made of conductive metal, such as copper or aluminum. If enhancement of the conductive interface is desired, the rod part 35 of the conductor can be provided with an enlarged generally frusto-conical surface 25 disposed with its base towards the proximal end 31 of the rod part, and the sleeve part 36 of the conductor can be provided with an enlarged generally frusto-conical complementary bore 26.
In the embodiment of FIG. 3, a wall 38 is located within, and completely blocks, the annular passage 37 of the sleeve part 36 of the conductor, thereby dividing the passage 37 into two separate chambers. This wall 38, which can either be formed integrally with the sleeve part 36 of the conductor (as shown in FIG. 3) or comprise a separate member permanently fixed (e.g., threadably connected and/or welded) within the annular passage 37, completely seals the junction between the two parts of the conductor so that the gaseous or liquid environment within the steel enclosure 11 is effectively contained when the bushing 14 is in place.
- Although not shown in the drawings, it will be appreciated that the embodiments shown in FIGS. 2 and 3 may be modified so that the rod part (18 or 35) of the conductor is anchored to the insulator body 27 '' while the sleeve part (19 or 36) i5 fixed to the electrical equipment sealed within the enclosure 11.
53-110/kah As can be seen from the foregoing detailed description, this invention provides an improved high voltage bushing that can be externally separated from electrical equipment sealed within an enclosure.
Specifically, the invention provides a bushing having two threadably connected conductor parts which are externally separable, thus enabling fast and inexpensive replacement.
53-110/kah
Background Art High voltage equipment is commonly sealed within a welded enclosure. The seal is required because the enclosure contains either a gaseous (e.g., SF6) or liquid (e.g., oil) dielectric atmosphere within which the equipment operates.
To enable connection between the enclosed equipment and external power lines, a bushing is used to provide a conductor through the wall of the enclosure while simultaneously insulating the conductor from the enclosure and maintaining the seal.
Bushings typically consist of a unitary metal conductor encapsulated in epoxy insulation.
The inside end of the bushing (i.e., the proximal end of the conductor) is usually connected rigidly (e.g., by a metallic clamp and hardware) to the enclosed high voltage equipment, while the outside end of the bushing is designed to matingly receive a connector device, such as an elbow connector. The outside end of the bushing (i.e., the insulator body and/or the bushing-to-elbow interface) is subject to damage during both transportation and use which quite often renders the bushing unusable. In this event, the bushing must be replaced, which for a unitary bushing requires opening of the sealed enclosure and disconnection of the bushing from the high voltage equipment. Such replacement procedures are costly, time-consuming and often quite difficult to perform, 53-110/kah especlally when the equlpment Is located In the close quarters of an underground vault.
The present Inventlon provldes an Improved hlgh voltage bushlng whlch, If damaged, can be externally separated from elec-trlcal equlpment sealed wlthln an enclosure.
The present Inventlon also provldes such an Improved hlgh voltage bushlng havlng two threadably connected conduc~or parts, the flrst of whlch Is permanently connected to electrlcal equlpment sealed wlthln an enclosure, and the second of whlch Is externally detachable detachable from the flrst part.
The present Inventlon agaln provldes a hlgh voltage bushlng whlch may be qulckly, and therefore Inexpenslvely, sepa-rated from electrlcal equlpment sealed wlthln an enclosure.
Accordlng to the present Inventlon a bushlng, havlng an elongated conductor substantlally encased In Insulatlng materlal, whlch extends In sealIng relatlonshlp through an aperture In a sealed enclosure encaslng an electrlcal apparatus, comprlslng:
sald conductor havlng two parts, a flrst generally cyllndrIcal rod part whlch Is fIxed at Its proxlmal end of the electrlcal apparatus and whlch extends therefrom toward the aperture, and a second sleeve part havlng a generally annular passage dlsposed to clrcumferentlally engage the flrst rod part and thereby provlde a conductlve path therebetween; a one-plece Insulator seallngly attached to and substantlally encaslng the sleeve part of the conductor; means for threadably connectlng the two parts of the conductor such that connectlon and dlsconnectlon can be accom-pllshed from outslde the enclosure, thereby enabllng dlsconnec-tlon of the sleeve part and the one-plece Insulator from the electrlcal apparatus wlthout dlsmantllng the enclosure, sald con-nectlng means comprlslng a screw, a clrcumferentlal shoulder wlthln the passage of the sleeve part of the conductor for seat-Ing a head of the screw, and a threaded bore In a dlstal end of the rod part of the conductor for recelvlng a threaded end of the screw; and means for sealIng the Junctlon of the two parts of the conductor so as to malntaln the envlronment wlthln the enclosure.
Sultably the bushlng further comprlses conductlve sprlng means dlsposed wlthln the passage of the sleeve Part of the conductor between and contlguous wlth the clrcumferentlal shoulder and a dlstal end of the rod part of the conductor. Deslrably the seal-Ing means comprIses at least one reslllent 0-rIng dlsposed In a clrcumferentlal channel located along the passage of the sleeve part of the conductor. Preferably the sealIng means further com-prlses a reslllent 0-rlng dlsposed wlthln the passage of the sleeve part of the conductor between and contlguous wlth the clr-cumferentlal shoulder and a dlstal end of the rod Part of the conductor. Sultably the conductor further comprlses an enlarged generally frustoconlcal surface of the rod part of the conductor dlsposed wlth a base portlon toward a proxImal end of the rod part, and an enlarged generally frustoconlcal complementary bore In the sleeve part of the conductor.
In accordance wlth the present Inventlon, there Is pro-vlded a bushlng, havlng an elongated conductor substantlally encased In Insulatlng materlal, whlch extends In seallng rela-tlonshlp through an aperture In a sealed enclosure encaslng an electrlcal apparatus, comprlslng a conductor havlng two parts, a flrst generally cyllndrIcal rod part whlch Is permanently fIxed at Its proxlmal end to the electrlcal apparatus and whlch extends therefrom towards the aperture, and a second sleeve part havlng a ~enerally annular passage dlsposed to clrcumferentlally engage substantlally all of the fIrst rod part and thereby provlde a conductlve path therebetween; a one-plece Insulator seallngly attached to and substantlally encaslng the sleeve part of the conductor; means for threadably connectlng the two parts of the conductor such that connectlon and dlsconnectlon can be accom-pllshed from outslde the enclosure, thereby enabllng dlsconnec-tlon of the sleeve part and the Insulator from the electrlcalapparatus wlthout openlng the enclosure; and means for seallng i<~h the Junctlon of the two parts of the conductor so as to contaln the envlronment wlthln the enclosure.
In a partlcular aspect thereof the present Inventlon provldes a conductlng bushlng for provldlng a hlgh voltage carry-lng connectlon from the outslde to the Inslde of a sealed enclo-sure comprlslng, In comblnatlon: a one-plece Insulator body formed to be fItted through an aperture In an enclosure and to be sealed agalnst an outer wall of the enclosure; a two-plece con-ductlve connector passlng through the Insulator body and formedof a sleeve surroundlng a rod, one plece of sald connector belng adapted to be flxed to an electrlcal devlce wlthln the enclosure and the other plece of the connector belng sealed to sald Insula-tor body, sald connector pleces havlng matlng surfaces adapted to wedge together to form a good electrlcal connectlon when the rod Is drawn Into the sleeve; and means for releasably drawlng the rod Into the sleeve operable from an end of the Insulator body that It outslde the enclosure, whereby the means can be released and the entlre Insulator body and the connector part sealed thereto can be removed and replaced from outslde of the enclo-sure, sald means comprlslng a screw, a clrcumferentlal shoulder wlthln the sleeve for seatlng a head of the screw, and a threaded bore In a dlstal end of the rod for recelvlng a threaded end of the screw.
The present Inventlon wlll be further Illustrated by way of the accompanylng drawlngs, In whlch:-Flgure 1 Is a perspectlve vlew showlng a vault-style swltch equlpped wlth the hlgh voltage externally separable bush-lng of the present Inventlon;
Flgure 2 Is a sectlonal slde plan vlew of a flrst embodIment of the Inventlve bushlng;
Flgure 3 Is a sectlonal slde plan vlew of a second - 3a -~t~
embodIment of the Inventlve bushlng; and Flgures 4a and 4b are perspectlve vlew and a sectlonal slde vlew, respectlvely, of a dlsc sprlng.
Turning now to the drawlngs and referrlng fIrst to Flg.
1, there Is shown a hlgh voltage, vault-style -- 3b -' switch 10 designed for load interrupting switching, sectionalizing, testing or grounding of underground cable systems through 38kV. In a vault-style switch, the high voltage electric equipment is encased within a welded steel tank 11, which is hermetically sealed and fully submersible. A handle 12 is used for operating the enclosed switching equipment, and the operation of the switching equipment can be viewed through windows 13 in the side wall of the steel tank 11. Typically, the sealed steel tank 11 contains either a gaseous ~e.g., SP6) or liquid (e.q., oil) dielectric atmosphere within which the high voltage switching equipment operates. Bushings 14, held by brackets 15 in apertures through the side wall of the steel tank 11, are used to provide a conductive path through the wall of the enclosure, thereby enabling connection between the enclosed switching equipment and external power distribution lines, while simultaneously insulating the conductive path from the enclosure and maintaining the enclosure's seal.
These bushings typically have an operating range rating of 7~ to 38 kV.
Considering now FIGS. 2 and 3, there is shown a bushing 14 embodying the present invention which is positioned in an aperture 16 in the side wall of the steel tank 11, and is maintained therein by means of a bracket 15, weld-in studs 17a, and nuts 17b.
In accordance with an important aspect of the present invention, the bushing 14 comprises a conductor having two parts, a first generally cylindrical rod part which is permanently fixed at its proximal end to the electrical apparatus and which extends therefrom towards the aperture 16, and a second sleeve part having a generally annular passage disposed to circumferentially engage 53-110/kah , ' ' ' 1 ~ti~ 8~
substantially all of the first rod part and thereby provide a conductive path therebetween, a one-piece insulator sealingly attached to and substantially encasing the sleeve part of the conductor, and means for threadably connecting the two parts of the conductor such that connection and disconnection can be accomplished from outside the tank 11, thereby enabling disconnection of the sleeve part and the insulator from the electrical apparatus without opening the tank.
Referring to the embodiment of FIG. 2, it will be seen that the bushing 14 comprises a conductor having a first generally cylindrical rod part 1~ and a second sleeve part 19, each of which is made of conductive metal such as copper or aluminum. The sleeve part 19 of the conductor has a generally annular passage 20 disposed to slidably engage substantially all of the rod part 18, and thereby provide a conductive path therebetween.
The distal end of the rod part of the conductor has an axial threaded bore 21 for receiving the threaded end of a screw 22, such as a cap screw. The head of the screw 22 is seated on a circumferential shoulder 23 located within the passage 20 of the sleeve part 19 of the conductor, and thus the screw 22 serves to threadably connect the rod 18 and sleeve 19 parts of the conductor. The head of the screw 22 can be accessed through the exterior opening 24 of the sleeve part of the conductor by means of a screwdriver, Allen wrench, or other such tool, thereby enabling turning of the screw, and consequently, external connection/disconnection of the two parts of the conductor. The portion 20' of the annular passage 20 between the exterior opening 24 and the circumferential shoulder 23 is threaded so 53-110/kah 1~;6~'3~
that a threaded interfacing rod ~not shown) made of conductive material can be threadably connected therein. This interfacing rod allows electrical connection between the sleeve part 19 of the conductor and an external connector device (not shown), such as an elbow connector.
In order to enhance the electrical interface and improve the seal between the rod part 18 and the sleeve part 19 of the conductor, the conductor can be designed to comprise an enlarged generally frusto-conical surface 25 on the rod part 18, disposed with its base towards the proximal end 31 of the rod part, and an enlarged generally frusto-conical complementary bore 26 in the passage 20 of the sleeve part l9. Thus, when the rod and sleeve parts of the conductor are threadably connected by means of the screw 22, the frusto-conical surface 25 of the rod part and the frusto-conical bore 26 of the sleeve part matingly engage one another, and thereby improve the conductive path between the two conductor parts.
A one-piece insulator body 27, comprised of high grade epoxy insulation material, is permanently attached (i.e., sealed) to, and substantially encases, the outer surface of the sleeve part 19 of the conductor, thereby isolating the conductor from the walls of the steel enclosure 11. The portion 27' of the insulator body 27 which, in use, extends exterior to the steel enclosure 11 has a generally frusto-conical shape, and thus, can be readily connected to various well-known connection devices, such as elbow connectors. Moreover, the exterior portion 27' of the insulator body 27 has a pair of integral annular collars 28, 29 which are engaged by the bracket 15 to maintain the bushing in the aperture 16 in the wall of the metal enclosure 11.
53-110/kah .
If desired, a gasket 30 can be located between the collar 29 and the wall of the metal enclosure 11 to seal the junction therebetween.
In use, the proximal end 31 of the rod part 18 of the conductor, which may, among other confiyurations, be flattened (as shown in FIG. 2) or threaded ~as shown in FIG. 3), is permanently attached to the electrical equipment ~not shown) encased within the steel enclosure 11. The distal end of the rod part 18 of the conductor extends toward the aperture 16 in the wall of the enclosure 11, and the sleeve part 19 of the conductor slidably engages substantially all of the rod part, thereby providing a conductive path therebetween. To seal the junction between the two parts 18, 19 of the conductor, and thereby maintain the gaseous or liquid environment within the enclosure 11, a resilient O-ring 32 is disposed in a circumferential channel 33 located along the passage 20 of the sleeve part 19 of the conductor. As shown in FIG. 2, this circumferential channel 33 can be located in the enlarged bore 26 in the passage 20. To further enhance the seal between the two parts of the conductor, a resilient O-ring 34 may be disposed within the passage 20 between, and contiguous with, the circumferential shoulder 23 and the distal end of the rod part 18 of the conductor.
It should be noted that in situations where the enhanced sealing provided by the second O-ring 34 is not necessary, conductive spring means (such as one or more of the disc springs 40 shown in FIGS. 4a and 4b) can replace the O-ring 34 and thereby serve to enhance the conductive path between the two parts of the conductor. Disc springs made of copper-beryllium are particularly suitable for this purpose.
53-110/kah ~2~;68~3~
The portions of the bushing 14 which, in use, lie exterior to the steel enclosure 11, are subject to damage which may render the bushing unusable.
Specifically, the exterior portion 27' of the insulator body 27 is subject to cracking and/or chipping during transportation and use, and the exterior end of the sleeve part 19 of the conductor, including its threaded annular passage 20', is subject to damage such as cross-threading and melting under short circuit conditions if the associated connector device is not properly secured. The present invention enables disconnection and replacement of the sleeve part 19 of the conductor and the entire insulator body 27, while leaving the rod part 18 of the conductor attached to the electrical equipment encased within the steel enclosure 11. Thus, the steel enclosure 11 need not be cut open, making the bushing replacement procedure quick and inexpensive.
FIG. 3 shows an alternate embodiment of the inventive bushing having an insulator body 27 identical to the insulator body of the embodiment shown in FIG. 2, but which has a modified two-part conductor. Specifically, the conductor of the embodiment shown in FIG. 3 comprises a generally cylindrical conductive rod part 35 and a conductive sleeve part 36 having a generally annular passage 37 disposed to circumferentially engage substantially all of the rod part and thereby provide a conductive path therebetween. The exterior surface of the rod part 35 and the surface of the annular passage 37 of the sleeve part 36 are complementarily threaded so that the two parts of the conductor can be threadably engaged. Thus, the entire insulator body 27, and the sleeve part 36 of conductor permanently affixed 53-110/kah i .
thereto, can be externally disconnected from the rod part 35 of the conductor and removed from the aperture 16 in the wall of the steel enclosure 11 by simply removing the bracket 15 and rotating the insulator body 27.
As with the embodiment shown in FIG. 2, the two parts 35, 36 of the conductor shown in FIG. 3 are made of conductive metal, such as copper or aluminum. If enhancement of the conductive interface is desired, the rod part 35 of the conductor can be provided with an enlarged generally frusto-conical surface 25 disposed with its base towards the proximal end 31 of the rod part, and the sleeve part 36 of the conductor can be provided with an enlarged generally frusto-conical complementary bore 26.
In the embodiment of FIG. 3, a wall 38 is located within, and completely blocks, the annular passage 37 of the sleeve part 36 of the conductor, thereby dividing the passage 37 into two separate chambers. This wall 38, which can either be formed integrally with the sleeve part 36 of the conductor (as shown in FIG. 3) or comprise a separate member permanently fixed (e.g., threadably connected and/or welded) within the annular passage 37, completely seals the junction between the two parts of the conductor so that the gaseous or liquid environment within the steel enclosure 11 is effectively contained when the bushing 14 is in place.
- Although not shown in the drawings, it will be appreciated that the embodiments shown in FIGS. 2 and 3 may be modified so that the rod part (18 or 35) of the conductor is anchored to the insulator body 27 '' while the sleeve part (19 or 36) i5 fixed to the electrical equipment sealed within the enclosure 11.
53-110/kah As can be seen from the foregoing detailed description, this invention provides an improved high voltage bushing that can be externally separated from electrical equipment sealed within an enclosure.
Specifically, the invention provides a bushing having two threadably connected conductor parts which are externally separable, thus enabling fast and inexpensive replacement.
53-110/kah
Claims (13)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A bushing, having an elongated conductor substantially encased in insulating material, which extends in sealing relationship through an aperture in a sealed enclosure encasing an electrical apparatus, comprising:
said conductor having two parts, a first generally cylindrical rod part which is fixed at its proximal end to the electrical apparatus and which extends therefrom toward the aperture, and a second sleeve part having a generally annular passage disposed to circumferentially engage the first rod part and thereby provide a conductive path therebetween;
a one-piece insulator sealingly attached to and substantially encasing the sleeve part of the conductor;
means for threadably connecting the two parts of the conductor such that connection and disconnection can be accomplished from outside the enclosure, thereby enabling disconnection of the sleeve part and the one-piece insulator from the electrical apparatus without dismantling the enclosure, said connecting means comprising a screw, a circumferential shoulder within the passage of the sleeve part of the conductor for seating a head of the screw, and a threaded bore in a distal end of the rod part of the conductor for receiving a threaded end of the screw;
and means for sealing the junction of the two parts of the conductor so as to maintain the environment within the enclosure.
said conductor having two parts, a first generally cylindrical rod part which is fixed at its proximal end to the electrical apparatus and which extends therefrom toward the aperture, and a second sleeve part having a generally annular passage disposed to circumferentially engage the first rod part and thereby provide a conductive path therebetween;
a one-piece insulator sealingly attached to and substantially encasing the sleeve part of the conductor;
means for threadably connecting the two parts of the conductor such that connection and disconnection can be accomplished from outside the enclosure, thereby enabling disconnection of the sleeve part and the one-piece insulator from the electrical apparatus without dismantling the enclosure, said connecting means comprising a screw, a circumferential shoulder within the passage of the sleeve part of the conductor for seating a head of the screw, and a threaded bore in a distal end of the rod part of the conductor for receiving a threaded end of the screw;
and means for sealing the junction of the two parts of the conductor so as to maintain the environment within the enclosure.
2. The bushing of claim 1 further comprising conductive spring means disposed within the passage of the sleeve part of the conductor between and contiguous with the circumferential shoulder and a distal end of the rod part of the conductor.
3. The bushing of claim 1 wherein the sealing means comprises at least one resilient O-ring disposed in a circumferential channel located along the passage of the sleeve part of the conductor.
4. The bushing of claim 3 wherein the sealing means further comprises a resilient O-ring disposed within the passage of the sleeve part of the conductor between and contiguous with the circumferential shoulder and a distal end of the rod part of the conductor.
5. The bushing of claim 3 further comprising conductive spring means disposed within the passage of the sleeve part of the conductor between and contiguous with the circumferential shoulder and a distal end of the rod part of the conductor.
6. The bushing of claim 1 wherein the conductor further comprises an enlarged generally frusto-conical surface of the rod part of the conductor, disposed with a base portion toward a proximal end of the rod part, and an enlarged generally frusto-conical complementary bore in the sleeve part of the conductor.
7. The bushing of claim 6 further comprising conductive spring means disposed within the passage of the sleeve part of the conductor between and contiguous with the circumferential shoulder and a distal end of the rod part of the conductor.
8. The bushing of claim 6 wherein the sealing means comprises at least one resilient O-ring disposed in a circumferential channel located in an enlarged bore in the sleeve part of the conductor.
9. The bushing of claim 8 wherein the sealing means further comprises a resilient O-ring disposed within the passage of the sleeve part of the conductor between and contiguous with the circumferential shoulder and a distal end of the rod part of the conductor.
10. The bushing of claim 8 further comprising conductive spring means disposed within the passage of the sleeve part of the conductor between and contiguous with the circumferential shoulder and a distal end of the rod part of the conductor.
11. A conducting bushing for providing a high voltage carrying connection from the outside to the inside of a sealed enclosure comprising, in combination:
a one-piece insulator body formed to be fitted through an aperture in an enclosure and to be sealed against an outer wall of the enclosure;
a two-piece conductive connector passing through the insulator body and formed of a sleeve surrounding a rod, one piece of said connector being adapted to be fixed to an electrical device within the enclosure and the other piece of the connector being sealed to said insulator body, said connector pieces having mating surfaces adapted to wedge together to form a good electrical connection when the rod is drawn into the sleeve; and means for releasably drawing the rod into the sleeve operable from an end of the insulator body that is outside the enclosure, whereby the means can be released and the entire insulator body and the connector part sealed thereto can be removed and replaced from outside of the enclosure, said means comprising a screw, a circumferential shoulder within the sleeve for seating a head of the screw, and a threaded bore in a distal end of the rod for receiving a threaded end of the screw.
a one-piece insulator body formed to be fitted through an aperture in an enclosure and to be sealed against an outer wall of the enclosure;
a two-piece conductive connector passing through the insulator body and formed of a sleeve surrounding a rod, one piece of said connector being adapted to be fixed to an electrical device within the enclosure and the other piece of the connector being sealed to said insulator body, said connector pieces having mating surfaces adapted to wedge together to form a good electrical connection when the rod is drawn into the sleeve; and means for releasably drawing the rod into the sleeve operable from an end of the insulator body that is outside the enclosure, whereby the means can be released and the entire insulator body and the connector part sealed thereto can be removed and replaced from outside of the enclosure, said means comprising a screw, a circumferential shoulder within the sleeve for seating a head of the screw, and a threaded bore in a distal end of the rod for receiving a threaded end of the screw.
12. The combination of claim 11 wherein a gas-proof seal is utilized between said insulator body and said outer wall and a gas-proof seal is utilized between said conductive connector and said insulator body and a further gas-proof seal is disposed at said connector mating surfaces.
13. The combination of claim 11 wherein said mating surfaces are male and female frusto-conical surfaces so as to provide substantial electrical conducting surfaces between the pieces of the connector.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/896,529 US4767351A (en) | 1986-08-13 | 1986-08-13 | High voltage externally-separable bushing |
| US896,529 | 1986-08-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1266898A true CA1266898A (en) | 1990-03-20 |
Family
ID=25406367
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000526655A Expired - Lifetime CA1266898A (en) | 1986-08-13 | 1987-01-05 | High voltage externally-separable bushing |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4767351A (en) |
| CA (1) | CA1266898A (en) |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NO890093L (en) * | 1989-01-10 | 1990-07-11 | Eb Distribusjon | ELECTRIC LEADER TRANSMISSION. |
| US4957208A (en) * | 1989-05-24 | 1990-09-18 | American Standard Inc. | Multiple contact electrical connector portion for an automatic railway coupler |
| ES2037590B1 (en) * | 1991-06-26 | 1996-02-01 | Ormazabal & Cie | COUPLING SYSTEM BETWEEN ELECTRICAL APPARATUS MODULES FOR TRANSFORMATION CENTERS AND THE LIKE. |
| US5342998A (en) * | 1992-04-02 | 1994-08-30 | General Electric Company | Terminal bushing for electrical apparatus comprising a polymeric shell molded about a central conductor |
| US5281767A (en) * | 1992-10-30 | 1994-01-25 | A.B. Chance Company | Reduced mechanical stress bushing and conductor rod assembly |
| US5455465A (en) * | 1993-11-04 | 1995-10-03 | Alcatel Canada, Inc. | Rapid transit car electrical coupling apparatus and method |
| GB9412094D0 (en) * | 1994-06-16 | 1994-08-03 | Whipp & Bourne Ltd | Obturation plate and a method of fabricating same |
| US5904577A (en) * | 1997-03-04 | 1999-05-18 | S&C Electric Company | Separable, flexible electrical connection arrangement |
| US6194986B1 (en) * | 1998-11-03 | 2001-02-27 | Lapp Insulator Company | Quick bottom connection for a transformer bushing |
| US6372994B1 (en) | 1998-12-01 | 2002-04-16 | David Servies | Wrapped film sealing system for electrical equipment |
| US6702973B2 (en) | 2000-01-11 | 2004-03-09 | Mcgraw-Edison Company | Method of sealing a stud in a bushing |
| NO325743B1 (en) | 2006-07-05 | 2008-07-14 | Vetco Gray Scandinavia As | Underwater switching device |
| CN101136280A (en) * | 2006-08-31 | 2008-03-05 | Abb技术有限公司 | High voltage device, high voltage bushing and method of assembling said device |
| BRPI0716513A8 (en) | 2006-09-07 | 2017-12-26 | Abb Technology Ag | ELECTRIC INSULATING BUSHING AND METHOD FOR ITS PRODUCTION |
| JP5727839B2 (en) * | 2011-03-31 | 2015-06-03 | 矢崎総業株式会社 | Shield connector |
| EP2571034A1 (en) * | 2011-09-19 | 2013-03-20 | Siemens Aktiengesellschaft | Subsea transformer enclosure |
| EP4254436A1 (en) * | 2022-03-31 | 2023-10-04 | Hitachi Energy Switzerland AG | Bushing assembly for a housing for electrical |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB190905302A (en) * | 1909-03-04 | 1910-03-04 | George Edward Tate | Improvements in Electric Terminals. |
| US1536024A (en) * | 1924-12-13 | 1925-04-28 | Kvaal Albert | Connection piece for cable heads |
| US2866171A (en) * | 1955-06-06 | 1958-12-23 | Sylvania Electric Prod | Tube socket |
| US3153114A (en) * | 1962-01-24 | 1964-10-13 | Allis Chalmers Mfg Co | Bushing assembly for electrical apparatus |
| US3474386A (en) * | 1964-02-10 | 1969-10-21 | Edwin A Link | Electrical connector |
| US3267205A (en) * | 1965-08-10 | 1966-08-16 | Us Terminals Inc | Electrical terminals incorporating break-away pins |
| US3509516A (en) * | 1968-02-01 | 1970-04-28 | Mc Graw Edison Co | High voltage connector and entrance bushing assembly |
| US3512118A (en) * | 1968-02-02 | 1970-05-12 | Westinghouse Electric Corp | High voltage electrical connector |
| US3622688A (en) * | 1969-12-02 | 1971-11-23 | Rte Corp | Cable lead bushing |
| US3861776A (en) * | 1973-01-15 | 1975-01-21 | Multilam Corp | Electrical connector with terminal lock means |
| US3825320A (en) * | 1973-03-02 | 1974-07-23 | Us Navy | High-pressure optical bulkhead penetrator |
| US3861777A (en) * | 1973-09-20 | 1975-01-21 | Permali Inc | Separable electrical connector |
| US3883208A (en) * | 1973-10-25 | 1975-05-13 | Rte Corp | Visible break tee-connector |
| DE2556546C2 (en) * | 1975-12-16 | 1987-08-20 | Steag Ag, 4300 Essen | Device for conducting electrical current through a wall of an electrostatic precipitator which is under excess pressure on its inside |
| US4214118A (en) * | 1976-09-08 | 1980-07-22 | Gould Inc. | Electrical bushing |
| US4199213A (en) * | 1976-12-17 | 1980-04-22 | General Electric Company | Method of constructing an electrical connector switching module |
| US4353611A (en) * | 1980-03-06 | 1982-10-12 | Amerace Corporation | Bushing well stud construction |
| US4508413A (en) * | 1982-04-12 | 1985-04-02 | Allied Corporation | Connector |
| US4611093A (en) * | 1984-01-20 | 1986-09-09 | Colt Industries Operating Corp | Electrical bushing having a replaceable stud |
-
1986
- 1986-08-13 US US06/896,529 patent/US4767351A/en not_active Expired - Lifetime
-
1987
- 1987-01-05 CA CA000526655A patent/CA1266898A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| US4767351A (en) | 1988-08-30 |
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| MKEX | Expiry |