US1868606A - Combined insulating bushing and transformer - Google Patents

Description

G. E. JANSSON 1,868,606

COMBINED INSULATING BUSHING AND TRANSFORMER .Filed Dec. l, 1930 2 Sheets-Sheet l July 26, 1932.

7 L u, W 4 s m Wm July26, 1932. G. E. JANSSON COMBINED INSULATING BUSHING AND TRANSFORMER Filed Deo. 1, 1950 2 Sheets-Sheet Patented July 26, 1932` UNITED 'sT-Aras PATENT OFFICE n A. f l. GUSTAV E. JANSSON, F ATLANTIC, MASSACHUSETTS, ASSIGNORTO CONDIT ELECTRICAL MANUFACTURING CORPORATION, OF

Tron or MASSACHUSETTS SOUTH BOSTON, MASSACHUSETTS, A CORPORA- coMBINED msULAriNG Busnme AND TRANSFORMER Application' mea- Decanteri 1, 1936. serial mi 499,143.

This invention relates to high tension 'insulating bushings having means by whlch power at low potential can be derived from A the potential ofthe line connected with the high voltage terminal of the bushing for the operation of relays, measuring devices, synchronizing indicators and the like.

Heretofore small amounts of low voltage power have been obtained from a high tension insulating bushing by utilizing the electrostatic capacity between selected conducting parts of the bushing. The amount of power, however, -that is obtained in this way is wholly inadequate to perform all the operations desired and for which an electromagnetic transformer as a separate apparatus is now required. l

It is an object of the present invention to provide a novelconstruction for an insulating bushing having means by which an abundance of low tension power can be derived from the high tension line which is \connected to the bushing. In carrying out lthis object of the invention the voltagedrop between the hightension terminal and the groundv iange of the bushing is divided between a plurality of reactance unit and the primary winding of an electromagnetic transformer all of which are connected in series and are included in the insulating enclosing shell of the bushing. This arrangement permits the use of a relatively low voltage transformer, the insulation of which presents no particular diiiiculty.

A further object of provision of a voltage transformer, suitable to be incorporated in a high tension insulatinsulating bushings having auxiliary low.

potential terminals.^

Fig. 1' is an elevation partly in section of a i high tension insulating bushingv embodying the invention.

Fig. 2 is a section taken on line 2-2 of Fig. 1.

the invention the` Fig. 3 is a diagrammatic view of thepotential transforming elements of Fig. 1.

Fig. 4 is a sectional detail of a modified construction of reactor units.

Fig. 5 is an elevation partly in section of a potential transformer constructed in accord?. ance with the invention.,v

Fig. 6 is a section along line 6-6 of Fig. 5;

Fig. 7 is a diagrammatic view illustrating the potential transforming elements of Fig. 5. As shown in Fig. 1 of the drawings the potential transforming device embodying the invention is embodied in a high potential insulating bushing comprising an upper insulating section 10 which is provided with eX ternal insulating-capes 12, a lowerexternally corrugated insulating shell 14, and an intermediate metal connecting sleeve 16 of somewhat larger diameter than said shells which comprises the support for said upper and lower insulating shells and 'also for the busha port for a packing ring 32 -on which the lower end of said insulating shell rests and outwardly beyond said collar to provide a rover for the open upper end of said sleeve.

Bolts 34 extend through said 'flange 30 and an I upper outstanding flange 36 of said sleeve j which latter flange isv adapted to support the insulator in the casing wall 38 of an electric switch or transformer. Suitable packing-40 is finterposed between the confront e ing faces of said'anges 30 and 36 whereby to provide`a breakable fluid tight joint thereat. A tubular current conducting stud 42 is `extended axially through said lbushing and.v

beyond the ends thereof and is rigidly afixedat its lower end to the bottom of said lower insulating shell 14. To this end a tubular metal sleeve 44 is united with said stud at its lower end which is provided with an upper flange 46 which overlies the bottom wall of said shell. An outer metal ring` 48 is affixed to said sleeve beneath said shell whereb to secure the stud permanently in the bus ing at its lower end.l A metal collar 50 is secured, as by cement, to `the upper end of said insulating shell 12 and is provided with an outstanding attaching flange 52 on which`an oil reservoir is adapted to rest.

' Said reservoir includes an annular bottom plate 54 which rests upon said flange 52 and is secured thereto by bolts 56 having a central tubular upstanding wall 58 which closely surrounds the stud 42 and provides lateral support therefor at'its upper end. Radially outstanding webs 60 connect said tube 58 and bottom plate 54 between which webs passages 62 are provided which are in communication with the open upper end of said insulating shell 10. An outer cylindrical housing 64 between said insulating tube 72 16 of the bushing. (0

of glass is received in fluid tight manner in a groove 66 in' the upper surface of said plate 54, and a cap 68'isprovided, through which said stud extends' and ywhich. forms a cover for the open top of said cylinder 64. Said ca 68 is provided with acentral upstanding tubular neck through which said stud eX- tends and a terminal cap 70 is aixed, as by screwLthreading, to the upper end'of said stud in surroundin relation with said neck. Said stud-42 1s provided intermediate its ends with a tube of insulating'material 72 which may comprise a plurality of layers of bakelized aperor other insulating material, and three aterally spaced concentric insulating tubes 74, 76 and 78 are suitably supported and the sleeve core path of-low reluctance. A secondary 92 is located within said-core strucwindin ture ad]acent the inner 4cylindrical plate 84 thereof and a primary winding 94 is located between said seconda-ry winding and the out-l slde cylindrical core plate 86, and said windings are spaced apart from'each other and from the core plates by means of-the annular lnsulating spacers 96 whereby to insulate them from the core structure and from each other. A body of oil 98 is providedjn the interior of said bushing to a level intermediate the height of the glass eylinder 64 of va. high potential.

said reservoir-and is adapted to occupy the spaces between the transformer primary and the adjacent parts of the transformer, thus to provide a high degree of insulation for said.

inwardly through the ground sleeve for connection with the lowermost of a plurality of reactance units .hereinafter to be described. At-least one of the terminals of the secondary winding 92 is brought out through the side wall of said sleeve 16 to the insulated terminal 104 which constitutes thel low potential terminal of the bushing, the other terminal of said secondary winding preferably being grounded tothe sleeve 16.

In accordance with this invention the electromagnetic transformer above described is designed to -be energizedJ at a potential considerably 'lower than the potentialsof the bushing terminal 70, since it is not desirable to insulate the primary winding 94 for such Accordingly a plurality ofserially connected reactance units are' provided within the upper insulating shell lalong the length thereof which are included in series with the primary winding of said transformer between the grounded sleeve 16 and the high tension terminal 70 of the bushing. Said units, as shownl most clearly in Fig. 3, comprise the multi-turn windings 106, carried by the inner tube '7 2 andsimilar windings 108, 11'0 and 112 which are supported in vertically spaced relation on and are insulated byl said intermediate tubes 74, 76 and 78 respectively, the adjacent terminals of said ywindings being electrically connected by means of conductors 114, whereby to connect all of sald4 windings electrically in series. The lead 114 of said lowermost reactance unit 112 is electrically connected with the u`n-.

l'be insulated for only a small part of the total voltage of the high tension line connected with the bushing. The. several reactance umts may be designed to divide the voltage drop equally therebetween or where it is desired the up vermost reactance units may be wound of a igher4 resistance wire, whereby to assumeva greater proportion` of the drop. l

provide magnetic cores for the several reactance units.` Such a construction is shown in Fig. 4 in whicha pair of adjacent reactance units are separated by an annular U-shaped insulating ring 116 which is loosely received on the supporting insulating tube 74. Each winding is enclosed between inner and outer concentric insulating cylinders 118 and 120, one of which, as the inner cylinder 118, has. a bottom portion 122 which spaces apart said" cylinders.l Said cylinders 118 and are wrapped about with strips of soft transformer steel 4124 whichconstitutes a closed magnetic circuit about the winding and consequently considerably increases the reactance thereof. i*

In Figs-5, 6 and 7, the' invention is illustrated in connection with a potential transv former. As here shown the transformer comprises a cylindrical base portion having. the upper and lower detachably connected sections 126 and 128 having the proximate outstanding annular anges 126e and 128e through which bolts 129 extend, and the upper tubular insulating shell 130- which is provided with the external y capes 132. Said upper base portion 126 has an annular inwardly directed ange 134 which carries a packing rin on which the lower endof said insulating shell- 132 is received and an upstanding cylindrical collar 136 which is spaced apart from the lower end of said shell to receive a body .of cement 138 by which said shell is permanently secured to the ba'se. Said shell isv also provided at its upper end with an annular collar 140, which is perma-4 p nently' secured thereto by' cement -142 vand which has an annular outstanding iiange 144 to which an oil reservoir is secured in fluid tight relation. Said reservoir comprises upper and lower cylindrical metal plates 146 and 148 which are maintained in-spaoed relation by a central upstanding tube 150 which is formed integral with said lower plate'and against the upper endof which the upper end of which the upper plate 146 is arrangev to bear. 'A cylindrical glass tube 152 constitutes the outer wall of said reservoir. Said upper and lower plates 146 and 148 are secured together by means of peripherally arranged tie bolts 154which extend throughsaid upper and lower lates and the attaching y flange 144 of said she Said lower platei148 is formed with a plurality of passages 156 which are'disposed about the central tube 150 thereof and provide for free iuid communication" between the interior portion of said f y has a depending conducting stud portion 1630' 70 which projects downwardly into the insulating shell of said bushing, whereby to more eltlrellly distribute thestress at the top of the s e .i

An electromagnetic transformer 162 is located within the base portion 126 and is supported removably therein on an annular i bracket 164 which-is secured detachably `to the inner wall of said base portion by cap screws 166. Said transformer comprises a core frame 168, a primary winding and a secondary winding 172, both of which windings are located on and suitably. insulated. from the upper leg of the core. Leads 17 4 are brought outu from said secondary winding and extend through an insulating bushing` 176 exteriorly of said base portion and constitute the low tension terminals of the potential transformer. One lead 178 of the primary ;winding of said electromagneticvtransformer is connected to agrounded terminal 180 of said base andthe other lead 182 thereof is extended upwardly into the shell 130.-

A plurality of serially connected reactors 184 are disposed rwithin the insulating-shell 130 along'thelength thereof.l Said reactors are supported in superposed position in said -shell about a central insulating tube 186 which is secured at its bottom end by bolts 188 to the tubular upstanding neck 190 of a circular plate 1 92. Said plate 192 has an annular flange 194 which is secured bythe cap screws 195 to the llower face of the inwardly insulating spacing members 196 of gendirected annular. flange 134 at 4the up er end-of said base portion 126. Annu ar erally U-shaped section are interposed be- 'tween the several reactors fand serve to in- .sulate them one from the other. The three orted on a somewhat smaller insulating tube 198 which is suitably supported by said .insulating tube 186. The lead 200 of the uppermost reactor unit 184 is connected electrically with the central upstanding tubular portion 150 of plate 148 and through the upper plate 146 with the terminal 1 58. rl`he terminal 202 of said lowermost reactor unit is uppermost reactor units are similarly supno connected to the lead 182 of said electromag- 3m .,actor units. 1t will be evident that the primary winding 170v of the electromagneticl transformer is electrically connected in series with the reactors 184 between the high ten'- sion terminal 58 and the ground terminal 180. By suitably designing the reactance of the several reactors 184 the potential of the primary winding 17 0 of the electromagnetictransformer can be of such value that no, dillilicult problems of insulation are involved.

As shownin Figs. 5 and 6, the several reactors 184 are provided with magnetic cores which substantially envelop the reactor windings although in some instances the core may be dispensed with orl as here shown may be provided with an air gap. The cores herein shown comprise the generally annular bottom portion 204, which is substantially U-shaped in cross section and is provided with a gap 205, between the upstanding U-shaped arms of which the reactance windings 184 are received, and an upper circular cover rportion 206 having a corresponding gap 207, which is received on the upper ends of said U-shaped portion. As thus arranged the cores and the lnterposed insulating annular spacer members 196 constitutea supporting column for the reactor units which are held in alignment by the inner insulating tubes 186 and Means arel also provided to supply the primaryl winding ofl the electromagnetic transformer with a leading exciting current, for the purpose of correcting the phase angle displacement resulting-from the reactors 184.

Said means includes a frustro-conical insulating tube y208 having a relatively thick insulating wall in which a plurality of serial- .ly connected parallel condensersare arranged i along the length thereof. As shown most clearly in Fig. 7 each of said condensers comprises a pair oit concentric parallel plates a and an intermediate' overlapping plate b which is interposed between said outer plates a, the several plates of the condenser being supported and insulated from each other by the material of said tube. Each plate b is common to'two adjacent sets of outer plates a and thereby constitutes means for connecting the adjacent parallel condensers in series. The uppermost set of parallel plates a are connected electrically with the lead 200 of the uppermost reactor unit and the lowermost intermediate plate b is electrically consulating fluid, as oil, is adapted to occupy the casing to a level intermediate, the height of the reservoir at the top of the bushing, whereby to completely submerge the electromag- As thus arranged it willL netic transformer w1162, the reactors, and the condensers above described. The insulating tube 208 is provided with a series of peripherally arranged passages 214 adjacent the' lower end thereof which provide l for free circulation of the. oil about the condenser tube 208. The oil is also free to circulate by thermal action labout ther electromagnetic transformer and reactor units.

The potential transformerabove described presents an inexpensive and reliable arrangement for deriving low'potential power from a high tension line to perform the operations heretofore requiring the use of an expensive high potential electromagnetic potential transformeryand is free from many of the 'diilicult problems present in the insulation of such transformers.- It is also possible to greatly improve the phase angle of the secondary low tension power by winding all or certain ones of the reactance coils 184 of suitable resistance Wire.'

In my concurrently tiled application Serial No. 499,142,\l have described and claimed still another construction for obtaining the voltage drop between the high tension terminal and the primary winding of the electromagnetic transformer, certain features of which are disclosed in this application.

Various modications in the arrangement,

and construction ofkthe parts may be made without departing from thescope of the invention. l

I claim:

1. A combined potential transformer and insulating bushing comprising an outer enclosing shell, a conducting stud extended through said shell, high tension terminals at the ends of said bushing, an axial insulatin tubelocated within said shell, a plurality o reactance coils having central passages through which saidltube extends surrounding and carried by and' located invertically spaced relation along the length of said tube, means electrically connecting said reactance coils in series between a high tension terminal of said bushin g and ground, and a low tension lead extendedf exteriorly of said bushing deriving its power from a selected one of said reactance coils.

2. In a potential transformer, the combination of an enclosing casing comprising an upper insulating shell portion having a high p tension terminal at the top and a lower metal supporting portion, a plurality of reactance coils having aligned central passages arranged in superposed order along the length of said shell portion, an axial-insulating-tube extended through the passages in said coils and having a support at its lower endon said v base portion, means electrically. connecting said reactance coils4 in series between said high tension terminal and metal support, a lowtension terminal extended through and insulatedpfrom Isaid metal supporting portion, and means to supply power to said low tension terminal from one of said reactance coils. j

3. In a potential transformer, the combination of an enclosing casing comprising an upper insulating shell portion -and a lowermetal supporting base portion, an electro- A magnetic transformer located in said base ELO ings which are disposed about said tube in.

vertically spaced relation, annular insulatin spacer members also disposed about said tu between adjacent windings of said reactors, and means electrically connecting the 'windings of said reactors in series with the primary winding of said transformer, said secondary winding having oneof its leads exv,.in'inal.

tended exteriorly of said casing and constituting a low tension terminal of the potential n transformer.

4. In a potential trans-former, the combination of an enclosing casing comprising an upper insulating shell portion having a high tension termina-l at the top and a lower metalv base portion, an electromagnetic transformer located in said base portion having'primary and secondary windings, an inner insulating tube concentricwith said shell portion and spaced apart from the side walls thereof having a support at'the lower end on said base portion, a plurality of annular reactors located on said insulating tube along the length thereof, said reactors having the windings thereof electrically connected in series with each other and with the primarywinding of said transformer, the free terminal of said transformer primary having a grounded connection with said base and the free terminal of said uppermost reactor having an electrical connection with said 5. In a potential transformer, the combination of an enclosing casing comprising a lowerl base portion and an upper linsulating portion havlng a high tension terminal at the top, an inner insulating tube located within and spaced apart from the side walls of said insulating shell'and having a supportvat its lower end on 'said base portion and a plurality of superposed reactors carried by said -insulating tube along the length thereof having windings which are electrically connected in series,- nieans to connect the winding of said uppermost reactor electrically with said high tension terminal and the j winding of said lowermost reactor'with said f base, and a low tension lead extended exteriorly of said casing and having a power-transmitting connection with said connected reactors adjacent the 4base end thereof.

high tension ter- 6, a potential transformer, the combination of a iiuid tightenclosingcasing comprising a lower grounded base portion and an upper insulating portion having a high tension terminal at the top, an insulating tube vo y.

extended through said insulating shell, a p lurality of annular reactor units surrounding said tube and supported thereby in spaced relation from said shell, annular insulating spacin members surrounding said tube disposed etween adjacent reactor units, and" means electrically connecting the windings of said reactors electrically in series between aid high tension terminal and said grounded ase.

7. In a potential transformer, the combi` 4terminalat the top of said shell portion, an insulating tube extended within said shell portion, a; plurality of reactors carried by A said tube in superposed relation and supported by said tube in spaced relation with sa1 d outer casing, each of said reactors comprising an annular core member through which said insulating tube extends and an annular winding associated with said core member, annular insulating members surrounding. said insulating tube and disposed between adjacent lreactor units, and meanselectrically connecting the windings of said reactors electrically in series between said high tension l terminal' and said grounded support.

8: In apotential transformer, the combination of an outer tubular enclosing casing comprising a lower grounded support and an upper insulating shell having a high tension terminal at the top thereof, a column of superposed annular reactors located within said casing, annular insulating spacer members located between adjacentreactor units, and an axial insulating and supporting tube extended through said annular reactor units and spacer members arranged to sup ort them in 'spaced relation`from the side wal s of said enclosing casing, said reactor units arranged to be electrically connected in 'series between said high 'tension terminal and said grounded support.

l9. In 'a' 4potential transformer, the com-v. bination of an outer tubular enclosing casing comprising a lower grounded portion andan upper insulating shell portion,a high tension terminall at the top of lsaid shell portion, a

llo

iis YJ low vtension terminal carried by and insulated I I from `said grounded portion, a central insusulating spacer `members also surrounding said tube and interposed between adjacent reactor units, each of said reactor units comprising an annular core member having a winding thereon, means electrically connecting the windings of adjacent reactor units in series, a second insulating tube located withinsaid shell surrounding said reactor and having metal condenser inserts embedded in and insulated from each other by the material of the tube, and means electrically connecting the -condensers of said tube in shunting relation with said reactor windings.

` 10. In a potentialtransformer, the combination of an outer enclosing casing comprisinga lower metal base portion and an upper insulating shell having a high tension terminal at the top thereof, a central column of superposed reactance coils located within said casing having an axial passage therethrough, an axial insulating tube extended through said 'passage having a support at one end, whereb to support said coils in spaced centric and overlapping metal plates em-l bedded in and insulated from each other by` bushing, an

relation wit the side walls of said casing, asecond tube of insulating material located within said casing and surrounding said column of reactance coils having spaced conthe insulation of the tube comprising a series of vertically arranged condensers, and means electrically connecting said condensers inshunting relation with said reactance coils.

11. A high tension bushing comprising upper and lower insulatingshells and an intermediate connecting ground sleeve, high tension terminals at the remote ends of said shells, a low tension terminal carried by and insulated from said ground sleeve, a conducting stud extended through said shells and sleeve, an electromagnetic transformer located in said sleeve surrounding and insulated from vsaid stud having a primary winding, one terminal -of which is grounded on said sleeve, and a secondary winding, one terminal of which is connected with said low tension terminal, an insulating tube extended in said upper insulating shell between said transformer and the upper high tension terminal, and a plurality of serially connected reactance windings carried by said tube and electrically connected in series with said primary winding between said upper high tension terminal and the free terminal of said transformer primary.

12. The combination with a bushing insulator having a grounded support, of a conductor extendedthrough said insulator, high tension terminals at the ends of said insulator, an annular magnetic core member disposed withinsaid insulator about said conductor, a magnetizing winding for said core member, a low tension winding located in the field of said core member having low tensioned terminals extended exteriorly of said axial insulating tube surrounding 18. The combination with an insulating bushing'having upper and lower insulating shell portions and an enlarged vintermediate metal connecting portion, of an electromagnetic transformer located in said enlarged portion having a central passage therethrough, said transformer having a high tension primary and a low tension secondary winding, a stud extended through said bushing, high tension terminals at the ends of said bushing, an insulating tube surrounding said stud, and a plurality. of reactance windings carried by said tube and electrically connected in series with the primaryr winding of said transformer between a high tension terminal of said bushing and ground,

`said transformer secondary winding having a low tension lead thereof extended exteriorly of said bushing.

14. An insulating bushing having the combination of upper and lower insulating shells, an intermediate metal connecting sleeve, an axial stud extended through said bushing,

Vhigh tension terminals at the ends of said bushing, an insulating tube surrounding said stud, an annular magnetic core surrounding said tube in the vicinity of saidl sleeve, primarily and secondary windings associated with said core, said primary winding having one lead grounded on said sleeve, and said seeondary winding having a low tension lead extended exteriorly of said bushing, a plurality of vertically spaced reactance coils carried by said insulating tube along the length thereof having their coils electrically connected inseries, and means electricallyr connecting the uppermost reactance coil with a high tension terminal of said bushing and the lowermost coil with the other lead of said primary winding. 1

15. An insulating bushing having the combinati on of upper and lower insulating shells,

an intermediate metal connecting "sleeve, an axial stud extended through said bushing,

high tension terminals at the ends of said bushing, an insulating tube surrounding said stud, an annular magnetlc core surrounding said tube in the vicinity of said sleeve, ,pri-

vhigh tension terminal of said bushingl and fthe lowermost coil with the other lead of said primary winding, certain of said reactance coils having their windings composed of a high resistance material whereby f* to correct the displacement in the phase angle of said low tension secondary.

16. An linsulating bushing having the combination of upper and lower insulating shells, n an intermediate metal connecting sleeve, an axial stud extended through said bushing, high tension terminals at the ends of said insulating shells, a low tension terminal carried by and insulated from said sleeve, a plurality of spaced concentric insulating tubes surrounding said stud, a` plurality of reactance coils carried by said tubes and arranged in superposed order along the length of said upper shell, the uppermost of said coils having the turns thereof composed of high re-l sistance wire, means electrically connecting said reactance coils in series between a high tension terminal of said bushing and said sleeve, and a winding inductively connected with one of said coils having a connection with said low tension terminalu In testimony whereof, I have signed my name to this specification.

GUSTAV E. JANSSON.

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