US1859969A - Unitary transforming and circuit interrupting apparatus - Google Patents

Description

May 24:, E, JANSSON 1,859,969

UNITARY TRANSFORMING AND CIRCUIT INTERRUPTING APPARATUS.

Filed May 18, 1929 I of apparatus.

Patented May 24, 1932 UNITED, STATES PATENT OFFICE GUSTAV E. JANSSON, OF. ATLANTIC, MASSACHUSETTS, ASSIGNOR TO CONDIT ELECTRICAL MAN UFACTURINGYCORPORATION, OF SOUTH BOSTON, MASSACHUSETTS, A CORPORA- TION OF MASSACHUSETTS I UNITARY TRANSFORMING AND CIRCUIT INTERRUPTING APPARATUS Application. filed May 18, 1929. Serial No. 364,175.

This invention relates to transformer substations of relatively moderate power capacity which are adapted to be energized from a high potential power source, as a long (115- tance transmission line.

A transformer substation necessarily includes a stepdown transformer and a high potential circuit interrupter connected in the high tension leads to the transformer, both of which, usually, are rather expensive pieces An oil-immersed circuit interrupter, such as is suitable for the purpose, commonly includes a pair of high tension insulating bushings for each phase. These bushings, which must be widely spaced to provide adequate insulation in air between the conductors outside the switch enclosing casing, consequently increase the lateral dimensions of the switch very considerably over those which are necessary to insulate the live parts immersed in the insulating oil withm the casing. An increase in the size of the casing necessarily results in an increased expense.

It is an object of the present invention to provide a high tension circuit interrupter for a transformer substation which has no exposed high tension insulating bushings and 1n which all the live conducting parts are 1m mersed in oil whereby to reduce the overall dimensions of the interrupter.

v Another object of the invention is the provision of a'cir'cuit interrupter for a transformer substation wherein the high tension line terminals and the line conductors connected therewith are immersed in a quiescent body of insulating fluid.

Insulating bushings which are capable of insulatinga conductor at a very high potential in air are not only undesirable because of their relatively great size and the consequent increase in the dimensions of the switch casing but they are also very expensive to manudustrial customers substation in which the number of high tension bushings is minimized and which is much less expensive than has formerly been commercially possible.

A further object of the invention is the provision of a. high tension transformer and circuit interrupter unit wherein the bushings for the high tension side of the transformer serve to insulate the high tension leads for the interrupter, thereby eliminating all large and expensive bushings for the interrupter.

A yet further object is the provision of a transformer and circuit interrupter unit wherein the terminals and high tension leads of the interrupter are immersed in the oil of the transformer and the stationary and movable switch members are immersed in a second body of oil which is out of fluid communication with the oil in the transformer.

Another object of the invention is the provision of a transformer and interrupter unit wherein the contact members of the interrupter are accessible from outside the transformer casing and can be examined and repaired while maintaining inviolate the body of insulating oil about the switch terminals and the transformer.

A further object of the invention is the provision of a transformer and interrupter unit wherein the interrupter is located in two compartments carried by the transformer one of which is in free fluid communication with the transformer casing and the other of which is in free fluid communication with the atmosphere.

A yet further object of the invention is the provision of a transformer casing having a corrugated side wallprovided with a plane portion for the attachment of a circuit-interrupter casing, the interior of which is in fluid intercommunication with the transformer casing.

A further object of the invention is generally to improve the construction and performance of electrical distribution systems Fig. 2 is a sectional elevation of the substation of Fig. 1.

Fig. 3 is a plan view of the corrugated casing wall of the transformer showing the plane or blank wall portion to which the interrupter casing is adapted to be attached.

The substation embodying this invention includesaan oil immersed mu'lti-phase stepdownpower transformer A having'associated therewith a high tension oil immersed circuit interrupter B which is adapted to control the flow of current between the incoming high tension leads and the primary windings of the transformer.

Said power transformer includes an oval oil containing casing or shell havingthe side wall 10-which isprovided with heat-radiating corrugations 11. and the bottom wall12 onwhich the core 14 and the associated windings 16 of the transformer are supported. Endless metal bands 18 and 20 overlie the upper and lower sinuous edges of said corrugated side wall 10 and are secured thereto in afiuid tight manner by welding. Said bottom wall 12 is adapted to be secured permanentlyto said lower band 20 by welding. A cover :22 is provided at the top. of said casingwhich issecured removably and in a fluid tight manner to said upper band 18 by means of bolts 24. Said =cover 22 is preferably crowned-and supports at one side thereof the three similar upstanding and outwardly-inclined hightension insulating bushings 26. Said high-tension bushings are provided with exposed terminals 28 at their upper ends to which the phase leads of a three phase high tension power source are adapted to be separately. connected. Corresponding-low tension bushings 30areprovided at the opposite side offthe. transformer casing having upper exposed terminals 32 which. are adapted to beconnected with the low tension distribution circuit and havinglo werterminals 34 beneath the body. of oil within. the transformer casing which are connected with the low tension leads ofthe windings 16 of the-transformer.

I In accordance with the present invention, the side wall 10'is formed'from a blank or plane metal sheet of suitable dimensions which is vsuitably corrugated, as by passing it through suitable crimping rolls, to a point "D adjacent one end whereby to provide a blank. or; plane portion 36 at one end there- (if. ,The: sheet is thereupon bent to the oval shape of'Fig. 3 and the vertical edges thereofuare welded at E to provide a continuous oil'tight enclosurehaving the blank or plane sidewall portion 36extending from the top to'the bottom of the casing, .the remainder ofthe wall being corrugated. Said blank wall" is provided near the top thereof with afrectangul'ar'aperture 38 within which the open side of a rectangular casing F is received thereby forming a closure for said aperture and providing an oil-containing, conductor-receiving chamber at the side of said transformer casing. An outstanding peripheral flange-member 40 is secured as by welding to the casing F and bolts 41 are passed through said flange and screw-threaded into the wall portion 36 whereby to secure said casing removably to-said-transformer casing. A suitable ;,.gasket may be placed between the flange-wand the oasingwall of the transformer in the customary manner to insure a'fluid tight jointthereat.

Said casing F comprises the switch frame for the three phase oil immersed circuit interrupter and to thisend the bottom wall 42 thereof is provided with three pairs of laterally spaced apertures 43 in which are located the similar pairs of upright insulating bushings 44 an'd46 which comprise the stationary switch, members of the interrupter. Said bushings are provided with separate attaching flanges 48 by which they'are secured in a fluid tight manner to saidbdttom wall 42 of the casing, and arejfurther provided with axial conducting studs 50 which provide upper terminals 52 and 54 and which are terminated at'their lower ends in fixed contact blocks 56. Saidterminal members 54 are separately connected'electrically through conductors 55, one of which is shown in Fig. 2, with the corresponding phase terminal 56 of a'high'tension transformer bushing 26. The other interrupter terminal members '52 are separately connected electrically through conductors 58, but one of which is shown inFigJQ, with the corresponding fphase lead of the'high tension portion of the win'ding'16 of'the'transformer.

The terminals ofthe interrupter, including the upper portions of the'bu'shings which are customarily exposed in air, by'this construction are wholly immersed in the quiescent'body of insulating oil C whichoccupies the casing F and. the transformer casing 'A. The conducting leads'a'ttache'd to said "bushings are also immersedin and insdlated'b said oil. Thus, thebushings can be small and consequently cheap, .as compared with the usual construction.

An oil containing receptacleG is sec'ured detachably to the bottom of the wall 4:2 of casing F and depends "therebelow whereby to enclose and submergefthelive parts of said depending stationary switch members in insulating oil. A movable switch member including the bridging orbrus'h member 60 is adapted to separately bridge' the pairs of stationary contact blocks 56 of the interrupter within-said receptacle G whereb 'to complete the circuit'throug'hthe switc in the usual way. Thereis-a separatebrid'ging memberoO'for jeach 'phase ofth'e switch and 'all bridging memb'ers760 are .atlapted'to be moved simultaneously by means of separate lifting rods 62 which extend upwardly through individual tubes or passages 64 through the casing F and are operatively connected with suitable switch operating mechanism which is indicated diagrammat ically by the crank arm 66. The passages 64 are adapted to be free from communication with the casing F. Each of said passages may consist of a section of pipe extended through the top and bottom walls of casing F and having an internal diameter somewhat greater than the diameter of the lifting rods 62, which pipe may be welded at its upper and lower peripheral ends to the top and bottom walls of said casing in a fluid tight manner. It will thus be evident that the lower oil containing receptacle G is free from fluid communication with the casing F. Preferably a gas expansion space 67 having a vent 68 open to the atmosphere, is provided in the upper portion of said receptacle.

A mechanism housing H' is provided about the open tops of the passages 64 and encloses the switch operating mechanism.

It will be evident from the above description of the invention that all live conducting parts of the interrupter are wholly immerse-d in oil and that, as a result, the insulating bushings 44k and 46 of the interrupter need be very small compared with the usual. cushings such as the high tension bushings 26 the transformer, which are necessary to insulate the conductors in air. Obviously the spacing of the bushings can also be greatly reduced, since the presence of a quiescent body of oil about the terminals 52 and and the leads 55 and 58 greatly decreases the strike-over distance over that which must be provided in air.

Those parts of the interrupter. as the cooperating contact members, which are sub ject to impairment in service are readily accessible without disturbing the body of insulating oil within the transformer. Furthermore, the body of oil within the trans former, being entirelyseparate from that surrounding the separable switch members in the interrupter, can never become fouled from the products of circuit interruption and the deleterious action of the arc thereon.

The substation above described is particularly suitable for industrial customer substations since it is relatively inexpensive to manufacture and comprises a unitary construction which can be shipped as such. The elimination of six high tension bushings comparable in size and expense with the bushings 26 of the transformer effects a marked reduction in the first cost of the installation as well as in subsequent operatingcosts.

The construction may be modified in many ways without exceeding the scope of the invention.

I claim:

1. A unitary substation including a trans former having an enclosing casing adapted to contain a body of oil, a second enclosing casing connected with said transformer casing having separate upper and lower compartments, said upper compartment only being in free fluid communication with the transformer casing, an electric switch for the circuits of said transformer having separable contact members contained in said lower compartment and operating mechanism for said switch operating through said upper compartment.

2. A unitary substation including a transformer having an enclosing casing adapted to contain a body of insulating oil, a switch casing associated with said transformer casing having two separate compartments, one'of whichcompartments is freely open into the transformer casing and the other of which is separated from fluid communication therewith by a fluid tight barrier, cooperating circuit controlling contact members contained in said latter compartment, and operating mechanism for said contact members which is external of both casings and has an operating member that is extended through said upper compartment into said first compartment.

3. A unitary substation apparatus including a main transformer enclosing casing adapted to contain a body of oil, an interrupter enclosing casing having two separate compartments, one of which is next adjacent and is freely open into said transformer casing beneath the level of the oil therein, switch terminals disposed within said adjacent compartment and immersed beneath the oil therein and extended into the other of said compartments, said other compartment adapted to contain a separate body of insulating oil in which said terminals are immersed, cooperating circuit interrupting contact members contained in said other compartment beneath the oil therein, and operating mechanism for said interrupter which is extended through said first compartment into said second compartment and has means isolating it from the oil in said first compartment.

4:. A unitary substation apparatus including a main transformer enclosing casing adapted to contain a body of insulating oil, an interrupter enclosing casing connected therewith and freely open into said transformer casing beneath the level of the oil therein, said second casing having a partition therein providing two separate compartments only one of which is in fluid communication with said transformer casing, an insulating bushing common to both compartments and having a terminal at each end thereof disposed in a separate one of said compartments, separable interrupter components disposed within said fluid isolated compartment, a separate body of oil contained therein be- 4 mews neath which said components are immersed, said latter'compartment having an extension which extends through and terminates above the oilin said first compartment, and operating mechanism for said interrupter having an operating member which extends 7 through said extension into said latter compa-rtment.

15. A unitary transformer and circuit interrupter apparatus including a transformer enclosingcasing adapted to contain a body of oil, an interrupter enclosing casing attached tosaid transformer casing, said interrupter casing having an upper compartment which is freely open into said transformer casing beneath the level of the oil therein and a lower compartment which is isolated against fluid intercommunication with said upper compartment and transformer casing, said lower compartment adapted to have a body of insulating oil therein and a gas expansion space above the oil,.a conduit communicating with said gas expansion space and extended through saiduppercompartment and open to the atmosphere at its upper end, separable contact members in said lower compartment and switch operating mechanism disposed in said conduit and connected with said contact members.

6. A unitary substation apparatus including a transformer enclosing casing adapted to contain oil, an auxiliary casing carried by a side wall of said transformer casing and having an opening into said transformer casing beneath the level of the oil therein, a vertical conduit extended through said auxiliary casing open at its upper and lower ends and having a peripheral fluid tight c0nnection with the top and bottom walls of said casing, an open top receptacle secured removably to said lower casing wall about the lower open end of said conduit, stationary interrupter members carried-by said bottom casing wall andextended above saidwall into said casing and also below said wall into said receptacle, stationary contact members disposed within said receptacle and connected with said interruptermembers, movable contact memberscooperating withsaid stationary contact members, operating mechanism for saidinterrupter including an operating rod disposed in said conduit and connecting-said mechanism with said movable contactimember. V

In testimony whereof, :I have, signed myname to this specification.

GUSTAV E. JANSSON.

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