US1699342A - A cobpobation op new - Google Patents

Description

Jan. 15, 1929. Q I 1,699,342

- A. o. Aus rm MEANQ FOR RAISING THE. FLASH-OVER VOLTAGE OF BUSHING INSULATORS Filed Aug. 5. 1922 4 Sheets-Sheet l 9W1 M 6 $5 amx Jam 15, 1929. 1,699,342

A. O. AUSTIN MEANS FOR RAISING THE FLASH-OVER VOLTAGE 0F BUSHING INSULA'I'ORS Filed.- Aug. 5. 1922 4 Sheets-inst 2 l I 0N JNVENTOB Jan. 15, 1929.

1,699,342 A. o. AUSTIN MEANS FOR RAISING THE FLASH-OVER VOLTAGE OF BUSHING INSULA'I'ORS Filed Aug. 3, 1922 4 Sheets-Sheet 3 Gnome Jan. 15, 1929- A. O. AUSTIN MEANS FOR RAISING THE FLASH-OVER VOLTAGE bf BUSHING INSULATORS 4 Shets-Sheec 4 Filed Aug. 5. 1922 [N VENTAOR 651 3 ATTORNEY ings for transformers, switches, roofs, walls;

gra'emeagum. 15, 1929.

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mayors msmo ran 'rLAsE-fovnn voL'rAsE- or nusrrmemsunarrons. I

application filed August 8, 1922. Serial No. 578,358.

This invention relates to insulator bush or other structures thru which a high potential conductor passes and from which 'itis insulated. The invention has for its object the raisingof the voltage at which flash-over will occur between. the conductor and the external sup ort for the bushing for. any

' given type 0 bushing without changing the construction of the bushing itself.

The invention is exemplified in the com bination and arrangement of parts shown in the accompanying drawings and described in the following specification,-and is more particularly pointed out in the appended claims.

In the drawings? Fig. l is an elevation with parts in section showing one form of the invention.

modi cation. l

Fig. 4 1s a part elevation and part section Fig.2 is a similar View showing a different form.

F1 3-15 a sim lar-view showing another showing still another difierent form of the invention. In Fig. 1 the'numerallO designates a conductor which extends thru a supporting wall or plate 11, such'as the'cover of a trans former housing and from which the-c onduc tor is insulated by a bushing 12. The bushing may be composed of one or moresleeves 13 and be provided-with suitable petticoats .14 of any well known and approved form.

A supporting flange-15 is cemented to theinsulator 12 and rests upon the support 11 to. which it is attached. Suspended fromv the support .11 by hooks 16 is a ring 17 of dielec-' tric material such as porcelain. The ring 17 is U shaped in cross section and is provideda with a fitting 18 cemented or otherwise secured thereto, which is engaged by the hooks l6. The interior of thememher 17 is provided with a coating 19 of conducting. ma terial. The surface maybe sanded and electro-plated or may be otherwise covered with from this point. The su .forms electrical contact with the coating 19 a metallic coating forming a. conducting sur facewithin the member. A portion of the inner surface of the outer flange may be left uncoated adjacent the edge of the flange as shown at 20 to avoid danger of flash-over lator surface.

pporting hook 16 .so that the inner surface oi the member 17 will be at the same potential as the support 11.

' .In the'operation of bushings and other insulators where alternating current is used,

as conductors shunting portions of the 115?- are heaviest near the terminals their shunting effects will be greatest at these points. In the present invention, charging current is -supplied to the insulator at points removed from the terminal 11 in order to decrease the Since the chargingfrarrents I flow over the insulating surface.

port --11 is carried downwardly along the I bushing 13' to port. The coated surface 19 acts as a conpointspemoved from the sup denser element for supplying current to the insulator 'members 13. The dielectric 17 interposed between the covering 19 and the conductor 10 resists the tendency to flashover between the conductor-and the. coating l9 which would otherwise exist because of the decreased path from the support to the conductor produced by the presence of the conducting surface 19, The surfacelQ also acts as a flux distributor and decreases the concentration of the 'electro-st atic flux which would otherwise be present at the support 11.

This distribution of the flux helps to 'overcome the tendency present where concentration of electrostatic flux is found. \Vhile the coating 19 is shown as directly connected electrically .to the sup-y port. 11 of the conducting material, this direct .connection is not essential to beneficial operation since,'even if there were a break in the continuity of the conducting connection, the member 19 wouldbe charged as a -with.the expansion andcontraction of the .member 17 due .totemperature changes, as

would be the case iffasdlid metal member to 'flash-over'which is I condenser element or by streamers jumping were cemented-or otherwise rigidlysecured within the member 15. It w ll be apparent that flux distributing members may also'be connected with' the conductor '10 at the endsof the bushings. Such distributing members are shown at 20, 21 and 22 in Fig. 2, of the drawing. These members comprise dielectric plates turned backwardly at their outer edges and having their surfaces coated with a plating of conductingmaterial shown at 23, 24 and 25 respectively.

In Fig. 2 the insulator bushing comprises a hollowdielectric member 26 passing thru a support 27 by which it is "carried'and provided with suitable flanges orip'etticoats '28 on its upperend. A conductor 29 passes thru the interior of the bushing. Surrounding the bushing 26'and supported by the plate 27 are elements of a current trans- 20.

. conductor winding31. The winding 31 is connected with lead wires 32 by means of ormer comprisingan ironcorc and a which the current from the transformer may be carried to any desired instrumcntlf Transformers of this natures-re used in connection with bushings for operating relays or for connection .with instruments to inc i cate the amount-of current flowing in the main conductor 29, or forothcr purposes re uiring relatively small current values. A housing 33 encloses the transformer. elements and is supported b the plate 27.- lhe housing 33 is preferabl made of con ductingmaterial such as s eet metal. A dielectric-ring U-shaped in cross section is' shown at'34 interposed between the housing 33 and the bushing 26, andacovering the housing on the side toward the; adjacent end of the bushing. The ,ring 34% is suitabl supported by a bracket 35connected wit the supporting plate '27. In .this arrangement the metal of the current transformer constitutes the conductor member for sup plying charging current and forcont'rolling electro-static flux. The shell 33'bein'g onclosed in the dielectric member 34 operates in a manner similar to the metallic coatin 19 in the form of invention shown in Fig. 1. As previously employed current transformers used in connection with bushings have 0 erated'to decrease the flash-over value 0 the bushing, but by the present in vention not only is this objection'overcome but the transformer may be employed to acmu tually increase the flash-over value.

In Fig. 3 there is shown theiap lication of a current transformer 36'toa-liushing 37 of the typeshown in Fig.-v .1. The trans- 1 former C011 is covered byacasing 38=which which is us aped.

orms a rin -enciirclingthc bushing and in section to receive-the. "c011. .4 dielectric ring 39 encloses the case 38 and is cemented or otherwise secured to a bracket ring 40 carried by the supportin plate 41. The bushing is supported on the cove'rin plate 41 by a suitable fitting. 42 cemented to the bushing in the usual manner. In Fig. 4 there is shown a multiple sleeve type of insulator bushinghavin a hollow conductor 43 extending theret ru. The bushing comperises a plurality of straight tubular mom is 44 of dielectric material" and a pair of cover members 45 and 46 of similar material. enclosing the members 44.

Thecover members 45 and 46 are carried nected to one another by bolts 49, the memher 47 being provided with a flange 50 for securing 't to the plate or wall thru which shield 53 interposed between the transformer by suitable fittings 47 and 48 which are concore and theoutermost tubular member 44..

Supported on the pins 54 projecting toward the cndsof the bushing are dielectric covers 55 and 56 which serve a purpose similar to that ofthe dielectric rin'gs 34 and 39 previously described. It will be seen'fmm Fig. 4'

that the pins-54 fitloosely in the dielectric members 55ahd 56, leaving the members free" to expand and contract with temperature changes The'ends of' the conductor 43 may be provided-with insulating flux control members 57 and 58 to provide improved fiusi distribution and assist in decreasing the flash-over voltage .of the bushing.

The-insulated shields are particularly valliable for protectingsurfaccs under oil adja-' cent to electrode surfaces under high stress. The streamers which may start from the electrode over the adjacent surface may,

cause damage. due to the heat' generated. The insulated shields may beus'ed to reduce these streamers '.sothat a higher voltage may be applied without causing damage.

hefinsula'ted shields or controls may be used to prevent damage by eliminating the g surface steamers but increased flash-over usuall results. .-Bush flash ggers oviing to hea may I reat y improve b the a licatio'n ofthe Ersulated controls? pp The controls may beuse'd either inside or. tslde of the bushing to-eliminate destructwo or dangerous. potential gradients. Interior and eirterior members may used in conjunction whore convenient. 5

or switch bushings the danger-cf the chargduced. This 'eli mi r'iates'. the necessity of the surface of the-bushing by aings which normally=haveratlier low shunting steamers When used on. the outside of transformer metal s eh! between 'the level of the oil I g and the cover of the transformer or switch.

I Since the metal shield may be eliminated conducting material so member .traction, the conducting material within said dielectric member extending to a posisaid, insulator,

a shorter and cheaper bushingrnay be used and if there is any surface above the oil it is capable of furnishinga highdegree-of insulation, 7 1

. This is particularly valuable in 5 oil switches ,where the surface above the oil may be in fairly good condition'eompared to the surface below the oil which may .be

come very dirty from discharges.

claim-z r 1. In combination, a tubular insulator, a

conductor extending through said insulator, a support secured to the exterior of said insulator between its ends, a dielectric member of-fragile material surrounding said insulator adjacent the outer face thereof, said member being U-shaped in cross section and open at one side to permit assembly of conductingmaterial therein after-formation of said dielectric member, and conducting material within said dielectric member arranged to leave the inner walls of said dielectric free to move by expansion or contionbetween said support and one end of the closed end of said dielectric member being disposed between the within said dielectricmember and said end of said insulator.

2. In combination; a. bushing insulator having a conductor extending therethrough and having an exteriorsupport of conduct- I dug material between its ends, an element of away from said conductor conducting material connected with saidconductor at a point beyond the end of said insulator and extending toward said support, a dielectric covering for'said element, a member of conducting material-connected with said support and extending toward one end of. said bushing to a point nearer said' end thau'any portion of said support, and a dielectric covering disposed about the portion of said last-named member of conducting material farthest removed from said support.

" 4;. In combination, a tubular insulator, a conductor extending through said insulator, a support of conducting material for said insulator positioned between its ends, fiux'controls at the ends of said insulator connected with saidconduetor and extend ing therefrom toward said support, the portions of said controls nearest said support. being covered with dielectric material 1nterposed between said controls and said support, a member of condu extending toward an end of cting material said insulatorfrom said support to a point nearer saidend 1 of said insulator than any p ortion of said support, and a dielectric covering for said.

member of conducting material inter osed between said member and said end 0 saidinsulator.

5. In combination, a bushing insulator, a'

current transformer insulator etween its ends, a' ducting material for stud element encircling said I casing of con--- transformer element, and a dielectric covering for mid casin; interposed between the casing and theend of said bushing, said transformer easing I 1 constitutin; means for feeding charging current to the surface of said insulator.

6. In combination, a

bushing insulator, a a

conductor extending therethrough, a c'urrent transformer element enci suiator between its ends, ducting material for said rcling said ina casing of con 9 transformer 'element, a dielectric covering for said casing interposed bet-ween the casing and the Qua of said bushing, and flux control members connected with said conductor at the ends of said bushing and having-portionsthereof directed towardxthe middle and covered with dielectric of said bushing material Interposed between said members and the iniddle of said bushing, said transformer casing and flux control members constituting means for feeding charging .current to said bushinginsulator.

7. In combination, a busl having a conductor extending therethi'ou h',

the

surface of iing insulator a support of conducting material for said ni:

sulator between its ends, a former casing of conducting ried by mid support andel nected therewith and toward one end of said in'sula ering of of said insulator and to enable the material former casing ton-ct as an ele denser to supply charging c insulator.

8. In combination, .a-

bushing insulator current trans material car-. I ectrically conprojecting .therefroin- U tor, and a covdielectrie material interposed be-.-- tween said transformer casing and said end to resist flash-over from said conductor to said transformer casing of said trans ment of a conurrent-to said, i

, having a conductor extending therethrough, an exterior support of conducting material for said insulator between its ends, a. cur .rent transformeglcore carried by said sup-' port and encircling said insulator, a metallic housing for said transformer core extendmg from said support toward one end of 1 said insulator; and a coverin material interposed between and said end o'fsaid insulator m dielectric sa d housi to resist fiashover from said conductor to said housing and to raise the flash-over voltage of said bushing insulator by dccreasing'leakage currents on the surface of said insulator, said. transformer core and housing constituting with said covering of dielectric material the elements of a condenser for feeding charging current to said insulator.

9. In (()111l)lll 2ltl0ll. a bushing insulator having a conductor therethrougglnga support througlrwvhich said insulator extends, a current transformer element surrounding said insulator at one side of said support, a housing of conducting material for said trans-' former element connected with said support, and a hollow ring of dielectric material c0v-- ering said housing and interposed between said housing andthe end of said insulator, said'transformcr element and housing con-- stituting with said ring the elements of acondenserto feed charging current to said bushing insulator.

10. Aninsulator bushing comprising a tubular dielectric member having a conductor extending therethrough, a support of conducting material for said dielectric member intermediate the ends thereof, a current transformer element of conducting material encircling said tubular dielectric member between the ends thereof, and a dielectric ring U-shaped in cross section supported on and enclos ng the extremities of said transxformer element away from said-support.

11; An'insulatois ushing comprising a tubular dielectric mel her having a conductor extending therethrough, a 4 currenttransformer element of conducting material in the shape of a ring surrounding said dielectric member between the ends thereof, a support of conducting material for said transformer element, means for supporting. saidtubular member from said transformer element, and dielectric cover rings U-sha'ped in i cross section fittingover the edgesof said' transformer element to miniinize-discharge from said transformer element.

12. An insulator bushing comprising a tubular dielectric member having a conductor extending therethrough, a transformer element of conducting'material in the form of a ring surrounding said dielectric member between the ends thereof, means for se-" curing said dielectric member to the interior of said ring, a support fo' said ring disposed outside thereof, dielectric coverings for the edges of said ring, and dielectric casing members enclosing said tubular dielectric member and said transformer element.

13. A dielectric bushing comprising a plurality of concentric tubular dielectric meinbcrs having a conductor extending through the innermost member, means for supporting said tubular members and conductor,

a transformer element of conducting material surrounding fsaid tubular-members, a dielectrie-housingfor said tubular members and-transformer element, said housing being made in separate parts, a supporting ring of conducting, material for. said housing, means carried by said supportingring and extending between the parts of said housing and engaging said transformer element for supporting saidtrans'former element and for electrically connecting said transformer element with said supporting ring, and dielectric coverings interposed between the edges of said transformer element and the ends of said bushing. Y 14. An insulator bushing comprising a dielectric tubular member hating a conductor extending therethrou h, a current transformerelement of con ucting material in the form of a ring surrounding said tubular member betweenthe ends thereof, pins pro jecting from the edges of said ring, and" rings of dielectric mat-erial U-shaped in cross;

section supported by said pins, said ins ex-j tending into'thexopenings in 'saids'haped members. r M

15. A bushing insulator com rising a tubular dielectric member, a con uetoreritending through saidmember and projecting from opposite ends thereof, a support of con-. ducting material secured to said'mcmber between the endsthereof, a flux control memher of conducting material electrically connected with said support and extending therefrom toward one end of said ins-' lator to apoint nearer'the end of said insulator than said support, a dielectric con-ring disposed between said flux control member and said endof said insulatt r, and a two-part casing 9f diclectric;material enclosin -said insulator. and flux control member and carried by said-support.

16. A- bushing insulator com rising a tubular dielectric member, a con uctor extending through said member and projecting from the ends thereof, a support of conductmg material connected with said tubular dielectric member between the ends thereof, a housing'of conducting material for. a cur rent transformer, element encircling said tubular dielectric member between the ends thereof and supported by and electrically connected with said support, said housing extending toward one endofsaid tubular dielectric member beyond said support, a covering of dielectric material interposed between said transformer housing and said end of said tubular dielectric member, and a two-part dielectric casing carried by said support and enclosing'said tubular dielectric member and said current transformer housng, I 4 17. A bushing insulator, a. conductor extending through said insulator, and a secondary winding dis osed within said bushing insulator and F ductor a current transformer. 4

18. A bushing insulator, a conductor extending through said insulator, a secondary winding of a current transformer disposed within said insulator, and a bafiie ofdlelectrio material interposed between said conductor and secondary winding.

19. A bushing insulator, a support for said insulator connected thereto between the ends 39 former winding disposed within said-insulator and surrounding said conductor, and a orming with said condielectric covering for said transformer winding interposed between said windingand the end of said insulator.

21. A bushing insulator, an external support for said insulator disposed between the ends thereof, a conductor extending through said insulator, a secondary current transformer-winding disposed within said insulater and surrounding said conductor, a dielectric bafile interposed between said conductor and secondary winding,.a magnetic core for said winding electrically connected with the external support for said insulator, and a dielectric covering for said .winding and core interposed between said winding and the end of said dielectric bafile.

In testimony whereof I have signed my name to this specification on this 29th day of 'July, AD. 1922.

ARTHUR O. AUSTIN. a

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