CA2013254A1 - High-voltage outdoor electrical bushing - Google Patents

Abstract

HIGH VOLTAGE OUTDOOR ELECTRICAL BUSHING
ABSTRACT OF THE DISCLOSURE
A relatively high voltage outdoor electrical bushing for use, for example,as an entrance bushing on high voltage electrical equipment,such as an inter-rupter or the like, a portion is formed from an indoor bushing adapted to be connected to a shielded electri-cal cable which meets the dimensional industrial standard for indoor bushings. More specifically, the high voltage outdoor electrical bushing includes and indoor electrical bushing formed from a resinous ma-terial, such as an epoxy and a complementary prophylac-tic weathershed or bushing adapter formed from an elastomeric material, which provides the additional clearance required for outdoor applications. The bushing adapter also provides electrical stress relief at the elastomer to air interface and the elastomer to epoxy interface. Because of the standardization of the bushing used for both indoor and outdoor appli-cations, the cost of manufacturing outdoor bushings can be substantially reduced.

Description

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HIGH VOLTAGE OUTDOOR ELECTRICAL BUSHING ~ , ~ ACKGROUND OF,THE INVENTIQN ~
1. Field of th_ Invention : , The pr:esent invention relates to a relatively : 5 high voltage outdoorr electrical bu;shing, and~more particularly, to an ou.tdoor elect~ri¢al bushing ,(suit- ' ,~ able for connect'ion~to a bare elec.tric,al cable) which`
,~ includes a bushing formed, to the industrial dimensional . standard or ind~or'bushing~ (normally connected:to '~
,.; 10 shielded electrical cables~) and~a prophylacti.c~weather~
. s:hed or busbing adapter wh;ich~:includes~electrical :
stress relief and provides the re:quired clearance for outdoor applic',àtions. ~ :
,~ 2. Backqround~of~.the Invention High voitage~:elec~trical b~shings are known:~
, in the art. Ex,amples of;~such~ bushings are~disclosed ;,','~' i:n U.S. Pa~tent~Nos. 1,811,8'87; 1,899,658;7 3,071,672;
' 3,231,~666t 3,50~,106; 3,515~,799; 3,551,~587:an~d .,.~, ~,S63,S45. SuCh electrical bu~hings are g,enerally ' u~ed as en~trance bushings on various~ types of eLectri-cal' equipment,~such as interrupter swlt~ches and the like to allow.connection o the e:quipmen.t,to an ex-, :~, ternal electrical circuit. An example of such equip- ~
ment 1~ disclosed in U.S. Patent~No. 3.,947,650, as- ;
',~, 25 signed to the same assignee as th;e present inve.ntion.
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~; Depending on the application, such electrical equipment may be loca.ted outdoors or indoor~s. In indoor applications, the bushing is generally connected , .

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2~ 254 to a shielded electrical cable. However, in outdoor applications, the bushing is generally connected to a bare electrical conductor. Consequently, it is neces-sary to provide additional clearance between the bare elect-rical conductor, normally at a relatively high voltage and the e~uipment housing! normally grounded.
In such applications, weathersheds are provided to provide additional clearance between the bare electri-cal conductor and the equipment housing and to protect the bushing from flashover due to environmental factors such as rain, snow and the like. Examples of bushings adapted for outdoor use which include weathersheds are disclosed in U.S. Patent Nos. 1,811,887;
1,899,658; 3,071,672 and 4,563,545.
There is no known standaedization between bushings connected to bare electrical cables (outdoor bushings) and bushings connected to shielded electrical cable ~indoor bushings). Consequently, due to the different clearance requirements for indoor and outdoor bushings, electrical equipment manufacturers are re-quired to produce a separate bushing for indoor use and a separate bushing for outdoor use, which signifi-cantly increases the cost of such bushings.
Alterna~tively, U.S. Patent No. 1,899,658 discloses a method for modlfying the electrical equip-ment to which the bushing i8 attached to convert a bushing designed for indoor use to one which can be utilized in an outdoor application. However, such a modlfication can be relatively expensive and time consuming.
SUMMA~Y OF THE INVENTION
It is an object of the present invention to provide a high voltage outdoor electrical bushing which solves the problems associated with the prior art.

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_3_ 2~1~2S4 It is another object of the present invention to provide a high voltage electrical bushing, suitable for outdoor use. - ~ ~
It is yet a further object of the present S invention to provide a high voltage outdoor electrical bushing which utilizes a standard ~ndoor bushing with-out the necessity of any modification to the equipment to which the bushing is attached.
It is yet another object of the present invention to provide standardization of the bushings used for indoor and outdoor applications.
Briefly, the present invention relates to a relatively high voltage outdoor electrical bushing used, for example, as an~entrance bushing on high lS voltage electrical e~uipment, such as an interrupter or the like, a portlon of which is formed to meet the dimenslonal lndustrlal standard for indoor bushings.
More specifically, the high voltage outdoor electrical bushlng includes an indoor electrlcal bushing formed -~ 20 from a res~nous material, such as an epoxy, and a complementary prophylactic weathershed or bushing adapter formed from an elastomeric material, which ; provides the add~tional clearance required for outdoor appllcatlon~. $he bushing adapter also provides elec-trical stress relief at the elastomer to air interface and the elastomer to epoxy interface. Because of the standard~zatlon of the bushing used for both indoor ~` and outdoor applications, the cost of manufacturing `~ ~ outdoor bushlngs can be substantially reduced.
~, 30 DESCRIPTION OF THE DRAWING
These and other ob~ects and adva~tages of the present invention will become readily apparent ~ upon con~ideeation of the following detailed descrip--~ tion and attached drawing, whereins FIG. 1 is an elevational view, partially in section, of a high voltage outdoor electrical bushing assembly in acFordance with the pFesent invention, ~ ' ' . , _4_ 2~13254 shown attached to a housing of an interrupter switch or the like;
FIG. 2 is an elevational view of an alternate embodiment of a portion of a termination stud on a high voltage outdoor bushing assembly in accordance with the present invention;
FIG. 3 is similar to FIG. 2 and illustrates another alternate embodiment of a portion of a termina-tion stud on the high voltage outdoor bushing assembly in accordance:with the present invention;
FIG. 4 is an elevational view, partiaIly in section of an alternate embodiment:of a bushing forming a part of the high voltage outdoor bushing assembly in accordance with the present invention;
lS FIG. 5 i~ a partial se~tional vi.ew of a hlgh voltage bush1ng assembly wlthout ~tress relief which illustrates the electrical field lines in percent of Iine to ground voltage adjacent an embedded flange in the bushing;
FIG. 6 is similar to FIG. 5 and illustrates : the electrical field lines with the addition of stress relief in accordance with the present invention;
FIG. 7 i~ a view of a conductor rod illus- -trating a method of making a bushing adapter in accord- .
ance with pre-ent invention;
PIG. 8 is similar to FIG. 7 and illustrates and subsequent ~tep ln the method of maklng a conductor rod in accordance wlth the pre8ent inventiont and FIG. 9 18 a sectiQnal view of a bushing adapter ln accordance with the present invention.
DETAILED DBSCRIPTION
The high voltage outdoor bushing assembly in accordance with the present invention is generally ldentlfied by the reference numeral 20. The assembly includes a bushing 22 and a bushing adapter 24. The high voleage bu~hing assemb1y 20 1- a'apted eO be .

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used, for example, as an entrance bushing on various types of electrical equipment, such as an interrupter switch as disclosed in U.S. Patent No. 3,947,650, - assigned to the same assignee as the present invention and hereby incorporated by reference. When used as an entrance bushing, the high voltage bushing assembly 20 is rigid}y mounted to a tank or housing 26 of the electrical equipment. More specifically, the~bushing assembly 20 is disposed in an aperture 28, for example, on the top of the housing 26, such that a portion of the bushing 22 extends inwardly into the housing 26 and a portion extends outwardly from the top of the housing 26.
The bushing assembly 20 is then rigidly lS attached to the housing 26. Various means are known in the art for attaching the bushing assembly 20 to a housing 26. For example, as shown in FIG. 1, the bushing 22 is provided with an annular metallic flange 30 which extends radially outwardly from the bushing 22. The flange 30 is embedded In the bushing 22 and welded to the housing 26. However, it should be ap-parent to those of ordinary skill in the art that the principle~ of the present invention are equally appli-cable to a bushing 32, such a~ illustrated in FIG. 4, which does not include an embedded flange but, rather, an integrally for~ed flange 31, for example, from epoxy. SuCh bushings 32 include a clamp 33, fa~teners 35 and one or more gaskets 37 forming a clamping assem-bly 39 to allow bushing 32 to be clamped and gasketed to the hou~ing 26 to form a seal therebetween.
An important aspect of the invention relates to the fact that a standardized bushing 22 or 32 which conforms to the industrial dimensional standard for indoor bushings ~i.e., bushings normally attached to a shielded cable), can be used in an outdoor (i.e., connected to an unshielded cable) application with the addition of a prophylactic weathershed or bushing adapter 24 illustrated in FIG. 9. More specifically, ..
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the bushing 22 or 32 is designed to conform to the dimensional standards for bushings connected to shielded electrical cables promulgated in ANSI/IEEE
Std. 386-1985, entitled IEEE STANDARD FOR SEPARABLE
INSULATED CONNECTOR SYSTEMS FOR POWER DISTRIBUTION
SYSTEMS ABOVE 600 VOLTS, which is hereby;incorporated by reference. This standard applies to bushings with various ratings above 600 volts. For example, FIG.
10 relates to 27 kilovolt ~kv), 600 amperè(A) bushings while FIG. 11 relates to a 38~kv, 600 A bushing. FIG.

3 relates to a 15-38 kv, 200A bushing. It will be appreciated by those of ordinary skill in the art that the principles of the present invention are ap-plicable to all such dimen~ionally standard bushings lS adapted to be connected to shielded électrical cables.
The bushings 22 and 32 are exemplary and formed from epoxy, normally used in indoor applications for connection to shlelded cables. An example of bushing 22 i8 available from Joslyn Power Products Corporation of Alsip, Illinois under Part No. 030B900, for example, for a 27 kilovolt application~. By uti-lizing a standardized bushing normally used for connec-tion to a shlelded cable 22 or 32 in the assembly of the high voltage electrical bushing assembly 20 for outdoor u~- normally connected to unshielded cables, the cost of aanufacturing such an outdoor bushing can be significantly redu¢ed.
In outdoor applications, where the bu~hing normally attached to a bare electrlcal conductor ~not 8hown), the bu8hlng adapter 24 is required to provlde clearance between the bare electrical conduc-tor, generally at a relatively high voltage and the equipment housing 26, normally grounded, to prevent flashover. The axial length of the bushing adapter 24 is dependent upon the magnitude of the electrical voltage at the bare electrical conductor. Thi~ length is ad~usted by th- number o} skirt portions 34 used :

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to for~ the weathershed 24. Such clearance require-ment~ are clearly within the ordinary skill in the art.
The bushing adapter 24 is formed as a housing , with an elastomeric material concentrically disposed about the bushing 22. An annular well 38 is formed at one end having a contour complementary to the outer contour of an upper portion 40 of the bushing 22.
The bushing adapter 24 includes a centrally disposed electrical conductor or, bushing rod 36, disposed be-tween roughly the top 41 of the well 38' and extends outwardly from the top skirt portion 34 of the bushing adapter 24. When the bushing adapter 24 is assembl,ed to the bushing 22, the bu~hing rod 36 in the bu~hing adapter 24 is adapted to be mated with a bushing rod 42 in the bushing 22 to form a continuous electrical connection therebetween.
various means are known for mating of the bushing rods 36 and 42. For example, the top end of the bushing rod 42 may be provided with a threaded hole, axially aligned with a threaded ho}e provided `
in the bottom portion of the bushing rod 36. A
threaded stud 44 may then be received in the threaded holes in the bushlng rods 36 and 42 to make a secure connection therebetween. A portion 43 of the bushing rod 36 extending outwardly from the weathershed 24 may be provlded with a pair of flats 45 to facilitate a~-mbly.
In order to reduce the electrical stress at the elastomer to air interface and the electrical stress at the elastomer to epoxy interface ~e.g., bushing 22 interface), means are provided to reduce the electrlcal stress in these areas. More speclfic-ally, one or more in~erts 46 and 48 may be provlded.
The insert 46 is a stress relief insert and i8 formed -~ from an ela~tomeric semiconductor material and is formed as a ring disposed at tbe base of the bushing : .

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adapter 24 and acts as an interface between the bushing 22 and the bushing adapter 24. The second insert 48 is a shielding insert, also formed as a ring, may be provided at the interface between the top of the bush-S ing 22 and the top 41 of the well 38, formed in theweathershed 24. The stress relief insert 46 reduces the electrical stress at the elastomer to air interface and the elastomer to epoxy interface. This is illus-trated in FIGS. 5 and 6. FIG. 5 illustrates a portion of a bushing assembly 20 wherein equal potential lines 50 are shown as a percentage of line to ground voltage due to the electrical potential difference between the bushing rods 36 and 42 (generally at a relatively hlgh voltage) and the annular flange 30 (normally at ground potential). As shown in FIG. 5, the egual potential lines 50 are relatively closer together causing a relatively high electrical stress at the base of the bushing 22. Such electrical stress can break down the air adjacent the bushing 22 and cause the bushing assembly 20 to flashover. With the addi-tion of the stress relief insert 46 and 48 as shown in FIG. 6, the egual potential lines 50 are spread out relative to th- bushing rod 42 which result~ in reduced electrical stres~ at the epoxy to elastomer interfsce and the elastomer to air interface.
The ~hielding insert 48 is for shielding trapp d air pocket~ between the conductor 43 to epoxy int-rfac- and the epoxy to elastomer lnterface (i.e., n-~r th- interface between the surfaces 59 and 41).
I any alr is trapped because of an imperfect fit of the components, any electrical voltage stress is eli-minated because the edge of the high voltage surface in effect has been moved to the outer surface of the shielding insert 48.
Another important aspect of the invention relates to a method of manufacturing the bushing adapter 24. Initially, the conductor rod 36 is prepared. ~`

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g The conductor rod 36 may be fabricated with variouS
high electrical conductivity metallic members, such as AA 6262-T9 aluminum or ASTM B301 copper, alloy 145, ~02 tempered. If aluminum is used for the conduc-tor rod 36, it may be electro-tin-plated with approxi-mately 0.8 thousandths of an inch (mils). rf the conductor rod 36 is formed from a copper alloy materi-al, it may either be used as is or electro-tin-plated with approxi~ately 0.2 mils.
After~the electro-tin-platlng process, the conductor rod 36 should be cleaned.~ For example, the conductor rod 36 may be degreased in an~ultras~onic degreaser to remove machine oil and other contaminants.
After the conductor rod 36 is degreased, it may be lS wiped down with a solvent, such as, methyl~ethyl ketone, with a clean, }int-free towel with an upward motion toward~ the top of the conductor rod 36. After the conductor rod 36 is cleaned, it is placed in an appropriate fixture ~not shown) for further processing.
Once the conductor rod 36~iJ in the~fixture, the conductor rod 36 is prepared for one or more coats of adheslves. ~Mor- specifically, the conductor rod 3~6 is masked with masking tape. FIG. 7 illustrates portions 50 and 52 of the conductor rod 36 which should be masked. Ma~king tape is applied to a portion~50 since thi~ portion 50 will extend outwardly~from the weath-r~hed 24. This portion 50 may extend approxi-~at-ly one lnch in axial length. Approxlmately one-h-l~ inch of the conductor rod 36 1~ masked lnt-r-medlate the end o~f the conductor rod 36 in the area - ldentified with the reference numeral 52. The unmasked portlon 54 between the portions 50 and 52 may be ap-proxlmately one inoh. The portion 54 is unma~ked to allow electrical contact between the bushing rod 36 and a semiconducting heat-shrinkable tube 57, discus~ed below. After the conductor rod 36 is masked, an even coat of adhesive is applied Various types of adhe-:: :

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z54 sives may be used, such as Pliobond adhesive as manu-factured by the W J Ruscoe Company of Akron, Ohio The adhesive is then cured, for example, for one hour at 149C After curing, the adhesive may be allowed s to cool to ambient temperature Next, a piece of ethylene propylene rubber (EPR) heat-shrinkable tubing 57 is cut to the length 58 identified in FIG 7 The inner diameter surface of the heat-shrinkable tubing may be cleaned~with a solvent, such as Isopropanol The adhesive that is already cured on the conductor rod 36 should also be cleaned with a solvent, such as Isopropanol or Heptane Another adhesive, such as Chemlock 238, as manufactured by the Elastomer Product Division of Lord Corporation of Erie, Pennsylvania, may be applied over the first adhesive on the conductor rod 36 After the second adhesive has partially dried, the masking tape is removed from the conductor rod 36 The next step is to place the shielding insert 48 onto an end 59 of the conductor rod 36 as shown in FIG 8 The shielding insert 48 is formed with an annular shoulder 60 forming a stepped surface 61 and may be compression molded with a semiconductive compound, for example, ethylene propylene diene monomer 2S ~EPDM) After the shielding insert 48 is in place, the precut and precieaned semiconducting heat-shrink-able tubing 57 is slipped over the conductor rod 36 ~uch that one end rests on the stepped surface 61 of the hleldlng in-ert 48 as shown in FIG 8 The hoat-shrlnkabl- tubing 57 is then shrunk down with a proper torch near the stepped surface 61 to provide a good fit between the hea~t-shrinkable tubing and the shield-ing insert The entire assembly is then cured, for ` example, for one hour at approximately 149C After the assembly is~ cooled to ambient temperature, it should be allowed to stand for about twelve hours or more. Subsequently, the ds-embly may be degreased in .

2~13z5~-an ultrasonic degreaser and stored in a closed con-tainer until further processing.
Ne~t, the assembly is placed in a mold cavity along with the stress relief insert 46. The stress relief insert 46 may also be compression molded with a semiconductive EPDM compound. The weathershed 24 is then molded in a ram injection press with an elasto-meric material to form the completed bushing adapter 24, as illustrated in PIG. 9.
Tbe bushing adapter 24 is then assembled to the bu~hing 22 or 32. In order to facilitate assembly, a lubricant or grease may be applied to the mating surfaces. The conductor rod 36 in the bushing adapter 24 is then attached to the bushing rod 42 as discussed above.-When ass-mbled, the bushing adapter 24 will be in relatively tight contact with the bushing 2Z.
The botto~ surface 63 of the bushing adapter 24 will`
also be relatively tightly seated against the top of the flange 30.
Various types of terminal~ 62, 64 and 66 may be attached~to the free end 43 of the bushing rod 36 as shown in FIGS. 1, 2 and 3. For example, FIG. 1 ~ lllUstrates a threaded terminal 62 while FIG. 2 illus- ;
-~ trates a straight rod 64 and FIG. 3 illustrates a fIattened pad 6~6 with connection holes. In order to attach the t-rminals 62, 64 and 66 to the bushing rod 36, th- free end ~3 of the bushing rod 36 may be pro-vid-d ~ith a threaded hole ~not shown) for receiving a thr-aded portion ~not shown) formed on one end of ~; 30 the t-rmlnal 62, 6~ or 66. All such terminals are intended to be within the scope of the present inven-!' tlon.
Obviously, many modifications and variations of the present invention are possible in light of the 3S above teachings. Thus, it is understood that within the scope of the appended claims, the invention may .. . . . ..

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be practiced otherwise than as specifically designated above.
What is claimed and desired to~be covered by U.S. Letters Patent is set forth as follows:
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Claims (70)

1. A high voltage outdoor electrical bushing assembly comprising:
an indoor bushing having an electrical con-ductor; and a bushing adapter formed with a well comple-mentary to the contour of a portion of said indoor bushing having an electrical conductor and defining a terminal end for connection to an external electrical circuit and a bushing end for connection to said elec-trical conductor in said indoor bushing, wherein said bushing adapter is adapted to fit over said indoor bushing to provide additional electrical clearance for outdoor applications.

2. A high voltage outdoor electrical bushing assembly as recited in claim 1, wherein said indoor bushing is formed from a resinous material.

3. A high voltage outdoor electrical bushing assembly as recited in claim 2, wherein said resinous material is an epoxy.

4. A high voltage outdoor electrical bushing assembly as recited in claim 1, wherein said bushing adapter is formed from an elastomeric material.

5. A high voltage outdoor electrical bushing assembly as recited in claim 1, further including a terminal formed from an electrically conductive materi-al and electrically coupled on one end to said terminal end of said electrical conductor in said bushing adapter and having a free end for connection to an external electrical circuit.

6. A high voltage outdoor electrical bushing assembly as recited in claim 5, wherein said free end of said terminal is formed as a rod.

7. A high voltage outdoor electrical bushing assembly as recited in claim 5, wherein said free end of said terminal is threaded.

8. A high voltage outdoor electrical bushing assembly as recited in claim 5, wherein said free end of said terminal is formed as a flattened pad.

9. A high voltage outdoor electrical bushing assembly as recited in claim 1, further including means for attaching said indoor bushing to an equipment housing.

10. A high voltage outdoor electrical bush-ing assembly as recited in claim 9, wherein said at-taching means includes a metallic flange, partially embedded within said indoor bushing.

11. A high voltage outdoor bushing assembly as recited in claim 9, wherein said attaching means includes a clamping assembly.

12. A high voltage outdoor electrical bush-ing assembly as recited in claim 9, further including means for reducing electrical stresses at an interface defined between said indoor bushing and said bushing adapter.

13. A high voltage outdoor electrical bush-ing assembly as recited in claim 12, wherein said reducing means includes means for reducing electrical stresses at an interface defined between said bushing adapter and air.

14. A high voltage outdoor electrical bush-ing assembly as recited in claim 13, wherein said reducing means includes a stress relief insert dis-posed between said indoor bushing and said bushing adapter.

15. A high voltage outdoor electrical bush-ing assembly as recited in claim 13, wherein said stress relief insert is formed as a ring.

16. A high voltage outdoor electrical bush-ing assembly as recited in claim 15, wherein said stress relief insert is disposed adjacent a bottom portion of said bushing adapter.

17. A high voltage outdoor electrical bush-ing assembly as recited in claim 16, wherein said stress relief insert is formed from a semiconductive material.

18. A high voltage outdoor electrical bush-ing assembly as recited in claim 17, wherein said semiconductive material is an EPDM compound.

19. A high voltage outdoor electrical bush-ing assembly as recited in claim 9, further including a shielding insert.

20. A high voltage outdoor electrical bush-ing assembly as recited in claim 19, wherein said shielding insert is formed as a ring with an annular shoulder defining a stepped surface.

21. A high voltage outdoor electrical bush-ing assembly as recited in claim 14, further including a semiconductive material disposed to be in electrical contact with said electrical conductor in said bushing adapter and said shielding insert.

22. A high voltage outdoor electrical bush-ing assembly as recited in claim 21, wherein said semiconductive material is formed as a tube.

23. A high voltage outdoor electrical bush-ing assembly as recited in claim 21, wherein said semiconductive material is ethylene propylene rubber.

24. A high voltage outdoor electrical bush-ing assembly as recited in claim 19, wherein said shielding insert is disposed between said indoor bush-ing and said indoor bushing, adjacent a top portion of said indoor bushing.

25. A high voltage outdoor electrical bush-ing assembly as recited in claim 19, wherein said shielding insert is formed from a semiconductive ma-terial.

26. A high voltage outdoor electrical bush-ing assembly as recited in claim 25, wherein said semiconductive material is an EPDM compound.

27. A high voltage outdoor electrical bush-ing assembly as recited in claim 19, wherein said shielding insert is compression molded.

28. A high voltage outdoor electrical bush-ing assembly as recited in claim 14, wherein said stress relief insert is compression molded.

29. A high voltage outdoor electrical bush-ing assembly as recited in claim 22, wherein said tube is heat-shrinkable.

30. A high voltage outdoor electrical bush-ing assembly comprising:

an indoor bushing having a centrally disposed electrical conductor; and means for adapting said bushing for outdoor use without modification to the electrical equipment to which the bushing is attached.

31. A high voltage outdoor electrical bush-ing assembly as recited in claim 30, wherein said adapting means includes a weathershed.

32. A high voltage outdoor electrical bush-ing assembly as recited in claim 30, wherein said indoor bushing is formed to meet an industrial dimen-sional standard for such bushings.

33. A high voltage outdoor electrical bush-ing assembly as recited in claim 30, wherein said standard is IEEE Std-386-1985.

34. A high voltage outdoor electrical bush-ing assembly as recited in claim 30, wherein said indoor bushing is formed from an epoxy.

35. A high voltage outdoor electrical bush-ing assembly as recited in claim 31, wherein said weathershed is formed from an elastomeric material.

36. A high voltage outdoor electrical bush-ing assembly as recited in claim 30, further including means for reducing the electrical stress at an inter-face defined between the indoor bushing and the adapt-ing means.

37. A high voltage outdoor electrical bush-ing assembly as recited in claim 36, wherein said reducing means also includes means for reducing the electrical stress at an interface defined between said adapting means and air.

38. A bushing adapter for a high voltage outdoor electrical bushing for adapting an indoor bushing for outdoor use without modifying the electri-cal equipment to which the bushing is attached compris-ing:
an electrical conductor; and a housing disposed about said electrical conductor, said housing formed with a well at one end, complementary to the contour of a portion said indoor bushing.

39. A bushing adapter as recited in claim 38, wherein an exterior portion of said housing is formed with a plurality of skirt portions forming a weathershed.

40. A bushing adapter as recited in claim 38, wherein said electrical conductor is copper.

41. A bushing adapter as recited in claim 38, wherein said electrical conductor is aluminum.

42. A bushing adapter as recited in claim 38, further including means for reducing electrical stress at an interface defined between said housing and air.

43. A bushing adapter as recited in claim 42, wherein said reducing means includes means for reducing electrical stress at an interface defined between said housing and said indoor bushing.

44. A bushing adapter as recited in claim 42, wherein said reducing means includes a stress relief insert.

45. A bushing adapter as recited in claim 44, wherein said stress relief insert is formed as a ring.

46. A bushing adapter as recited in claim 45, wherein said stress relief insert is disposed adjacent a bottom portion of said bushing adapter.

47. A bushing adapter as recited in claim 44, wherein said stress relief insert is formed from a semiconducting material.

48. A bushing adapter as recited in claim 44, further including a shielding insert.

49. A bushing adapter as recited in claim 48, wherein said shielding insert is formed as a ring with an annular shoulder forming a stepped surface.

50. A bushing adapter as recited in claim 49, further including a semiconductive material dis-posed to be in electrical contact with said electrical conductor and said stepped surface.

51. A bushing adapter as recited in claim 50, wherein said semiconductive material is formed as heat-shrinkable tubing.

52. A bushing adapter as recited in claim 50, wherein said semiconductive material is ethylene propylene rubber.

53. A bushing adapter as recited in claim 47, wherein said semiconducting material is an EPDM
compound.

54. A bushing adapter as recited in claim 48, wherein said shielding insert is formed from a semiconducting material.

55. A bushing adapter as recited in claim 54, wherein said semiconducting material is an EPDM
compound.

56. A bushing adapter as recited in claim 44, wherein said stress relief insert is compression molded.

57. A bushing adapter as recited in claim 48, wherein said shielding insert is compression molded.

58. A bushing adapter as recited in claim 38, wherein said housing is formed from an elastomeric material.

59. A bushing adapter as recited in claim 38, wherein said housing is molded.

60. A method for making a high voltage outdoor electrical bushing assembly comprising the steps of:
(a) providing an indoor bushing with a predetermined outer contour and having a centrally disposed first electrical conductor;
(b) providing an electrical conductor;
(c) providing a bushing adapter with a well having a shape complementary to a portion of said predetermined outer contour.
(d) disposing said bushing adapter over said indoor bushing.

61. A method as recited in claim 58, further including the following step:
(e) providing one or more inserts for reduc-ing or shielding the electrical stress.

62. A method for making a bushing adapter for an indoor bushing to adapt it for outdoor use comprising the steps of: .
(a) providing an electrical conductor rod;
(b) masking predetermined portions of said electrical conductor rod;
(c) applying a first adhesive to said pre-selected portions of said electrical conductor rod;
(d) curing said adhesive for a predetermined time forming a prepared conductor rod;
(e) removing said masking; and (f) molding said prepared conductor rod into a housing with a well at one end formed into a predetermined contour.

63. A method for making a bushing adapter for an indoor bushing to adapt it for outdoor use comprising the steps of:
(a) providing an elongated electrical con-ductor;
(b) cleaning said elongated electrical conductor;
(c) masking predetermined portions of said elongated electrical conductor;
(d) applying a first adhesive to the un-masked portions of said elongated electrical conductor;
(e) curing said first adhesive at a prede-termined temperature for a predetermined time period;
(f) applying a second adhesive to the un-masked portions of said elongated electrical conductor;
(g) forming a shielding insert as a ring with an annular shoulder;

(h) placing said shielding insert at a predetermined end of said elongated electrical con-ductor;
(i) cutting a piece of heat-shrinkable tubing to a predetermined length;
(j) removing said masking;
(k) placing said heat-shrinkable tubing around said elongated electrical conductor to be in contact with said first shielding insert and with an unmasked portion of said elongated electrical conduc-tor;
(l) applying heat to said heat-shrinkable conductor to shrink it around said elongated electrical conductor forming an assembly;
(m) curing said assembly for a predetermined time period;
(n) allowing said cured assembly to cool to ambient temperature for a predetermined time period;
(o) forming a stress relief insert as a ring;

(p) positioning said stress relief insert with respect to said assembly within a mold cavity, and (q) molding said bushing adapter with a predetermined material having a well at one of a pre-determined contour.

64. A method as recited in claim 63, wherein said predetermined material is an elastomeric compound.

65. A method as recited in claim 63, wherein said shielding insert is compression molded.

66. A method as recited in claim 63, wherein said shielding insert is formed from a semiconducting material.

67. A method as recited in claim 66, wherein said semiconducting material is an EPDM compound.

68. A method as recited in claim 63, wherein said stress relief insert is compression molded.

69. A method as recited in claim 63, wherein said stress relief insert is formed from a semiconduct-ing material.

70. A method as recited in claim 68, wherein said semiconducting material is an EPDM compound.