US1796993A - Electric switching station - Google Patents

Description

March 17, 1931. HUBER 1,796,993

ELECTRIOSWITCHING STATION Filed. Feb. 4. 1928 2 Sheets-Sheet l Inven Tor' Her-man d.H.Huber-, by His ATTor'ne- March 17, 1931. HUBER 1,796,993

ELEGTRI C SWITCHING STATION EL i /oz Invenfor' Her-m cm dPLHuber',

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Patented Mar. 17, 1931 UNITED STATES PATENT OFFICE HERMAN J. H. HUBER, OF UPPER DARBY, PENNSYLVANIA, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELECTRIC SWITCHING STATION Application filed February 4, 1928. Serial No. 252,026.

My invention relates to electric switching stations and particularly to those which are adapted to control high potential power transmission circuits. Among the objects of my invention is the provision of an improved switching equipment of the metal clad type well adapted to outdoor use which shall insure safety against inter )hase short circuits, which shall facilitate safe operation, inspection and replacement of apparatus connected therewith, which shall embody a unit construction adapted to a wide variety of circuit layouts and which shall be simple and economical to manufacture, install and operate.

In the system to which my invention applies, the current source preferably has its neutral point grounded through a resistance and the bus bars of the respective phases as well as the feeder-s connected therewith are each enclosed in separate grounded metal tubes or armor, the space between the conductor and the armor being filled with insulating materal such as oil or compound. Since the switches and transformers of such a station may also be the iron clad outdoor type, it becomes unnecessary to provide a building in which to house the entire station, it being sufficient to provide only such buildings as are required to house the control apparatus, etc. and to provide facilities for the inspection and repair of apparatus when such cannot be done expediently in the outdoor location.

My invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

Referring to the drawing, Fig. 1 is a partial plan view of a switching station embody ing my invention; Fig. 2 is an end elevation of the structure shown in Fig. 1 drawn to a larger scale; Fig. 3 is a fragmentary sectional view taken on the line 3-3 of Fig. 2; Fig. 4 is a fragmentary sectional view taken on the line 4-4 of Fig. 3; Fig. 5 is a detaii of the auxiliary circuit connector; Figs. 6 and 7 are detail views of the shutter mechan sm; Fig. 7 being a section on line 77 of F g. 6; and Figs. 8 and 9 are circuit diagrams.

The switching station embodying my invention comprises the elevated supporting structure 1 shown as fabricated from structural steel members and carried by the columns 2 resting on concrete bases 3. The columns are arranged in two rows extending in the longitudinal direction of the structure and located adjacent the sides thereof. The elevated structure comprises the longitudinal tie girders 4 and a series of equally spaced cross girders 5 at the ends of which are the columns 3. The cross girders 5 divide the structure into bays each of which contains similar apparatus related to a separate feeder circuit which may be either incoming or outgoing. Because of the similarity of the bays, I have illustrated only one end portion of the structure including the first two bays, it being understood that the structure continues on in a similar manner to the extent found necessary to accommodate all the feeder circuits. The feeder cables 6 are shown as brought underground to the apparatus on the elevated structure, being protected where they emerge from the ground by the concrete posts 7. Supported from the cross girders in each bay are the two oil switch housing-s 8 each comprising a fabricated casing composed of steel plate or non-magnetic metal which opens downwardly and is adapted to receive a three phase switch unit to be described later.

Extending longitudinally of the structure adjacent its two sides are the main and reserve buses 9 and 10 respectively. The buses themselves are enclosed individually in separate tubes or armor 11 of non-magnetic metal such for example as copper or non-magnetic steel. The buses of each set are arranged in the same horizontal plane and are divided by the auction boxes 12 into sections of the same length as the bays. The junction boxes which also are formed of steel or non-magnetic metal depending on the magnitude of current carried by the buses are shown supported by the plates 14 extending between the tie girders and the switch housings. Suitable insulating spacers are provided inthe tubes 11 to keep the bus conductors centrally located therein and the space between the buses, connections thereto, etc. and the surrounding tubes and connection boxes is filled with insulating oil or compound. In addition all of the live parts are covered by solid insulation and are so spaced from the enclosing armor, which is well grounded, so that the station may be safely operated for a limited time at full voltage even though the oil of some portion should all leak out. Each tube section is provided with an expansion joint 16 to prevent damage due to changes in temperature. The bus connections also are made by flexible conductors for the same reason. To facilitate the removal and replacement of a bus conductor of any section, should such be found necessary, I have arranged the sections of the buses on two different levels, alternate sections being on the same level as shown in the drawing. The junction boxes 12 are provided with spouts 17 on opposite sides and at both levels, those not occupied by a bus being closed by caps 18. By this arrangement any bus section may be slid out of place after being disconnected at itsends and after the removal of the proper spout cap 18.

Extending across the structure in each bay are the phase conductors 20 of each three phase feeder circuit. These phase conductors like the buses are enclosed in tubes 21 of nonmagnetic metal forming sections, each section having an expansion joint as in the case of its bus tubes. The feeder conductors also are insulated from their surrounding armor by solid insulation and by oil similarly to the buses. The two levels on which adjacent sections of; the buses are carried I have spaced apart materially and have arranged the feeder conductors therebetween at an intermediate level, see Fig. 3. This avoids interference at the crossing points and simplifies the construction and the connections. Forming a part of and extending up from each switch housing 8 are the switch connection boxes 23 through which the phase feeder conductors 20 extend. These conductors connect at one end with the current transformers 24 to which connect the cables 6 and which are enclosed by the casings 25. At the opposite ends these conductors connect with the potential transformers 27 through suitable fuses 28 and resistances 29 which transformers have isolation contacts like the switches and are surmounted by the connection boxes 30. Short tubes 33 extend from the switch connection boxes 23 to the bus connection boxes 12 in which tubes are the phase conductors 34 connecting the buses to the isolating contacts in the switch connection boxes.

In each bay there are two three phase oil switch units 36 adapted to connect the feeder conductors of that bay to either the main or the reserve buses. Each switch unit has three pairs of isolating contacts 37 mounted on the upper ends of their insulator bushing 38 which when the switch is in elevated position to connect it with the circuit engages cooperating fixed isolating contacts 39 secured in the insulating shells 40 in the switch connection boxes 23 whereby isolation of the switch from the circuit controlled is effected by the lowering of the switch bodily from the supporting structure. The potential transformers 27 and their connection boxes 30 are provided with similar isolating connections 42 shown only in the circuit diagram, Fig. 8. whereby the transformers are isolated by being lowered from the structure. The downwardly extending flange 44 below each switch connection box 23 engages the top of the switch unit when the same is clamped in its elevated position, a suitable gasket preferably being used to make the 'oint tight to exclude dirt, rain and snow. fientilation of the space enclosed by the flange and insulation shells is provided by the small ventilators 45.

Each switch unit is firmly clamped to the supporting structure by means of the cams 47 of which there are three on each side of the switch housing, each engaging a roller 48 on the unit. The cams have ofi'set face portions, as shown in Fig. 4, whereby when each is moved to a position to release its roller, it will permit the lowering of the unit without interference therewith. Each cam is mounted on a short shaft and is operated by a crank 49. The three cranks on each side are connected together by the rod 50 which terminates in a screw 51 and threaded on this screw is the worm gear nut 52. Transverse shaft-53 has two worm gears 54 one meshing with each worm gear nut 52 and a hand wheel 55 whereby the six cams are simultaneously operatedby the turning of the single hand wheel.

The above described cam mechanism I have provided only for firmly clamping the unit to the structure; for raising and lowering the unit relative to the structure I have provided a separate mechanism now to be described. In Fig. 2 it will be seen that a track 58 rests on the same concrete foundations as the columns 2 and extends in the longitudinal direction of the structure.

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from the supporting structure, the carriage 1S pushed to a position directly beneath the unit, the platform is brought up to engage the bottom thereof, the clamping cams released and the platform lowered. It may be desirable to lower the unit only to the disconnect or isolated position. For retaining the unit in that position the supporting structure is provided with the latches 65, see Figs. 2 and 4-, which are mounted on the rods 66 extending along opposite sides of the switch housing, each rod having a handle 67, see Fig. 3, by means of which the latches connected therewith may be turned up out of the way when the switch unit is to be lowered beyond the isolating position.

The polyphase switches which I have shown each comprise a single cover structure with attached operating mechanism which may, for example, be of the solenoid or centrifugal type and secured to each cover structure are three separate tanks 70 enclosing the contacts of the respective phases. Each tank 70 is shown secured to the cover structure by means of the bolts 71, see Figs. 3

and 4. Because of the danger which might result from the removal of a tank while the switch is alive I have provided the guards 7 2 pivotallysupported from the brackets 73 on the switch unit. Each guard is constructed with a head portion arranged to cover two adjacent bolts, see Figs. 3 and 4:, and each has a tail portion 74. The latter is adapted to engage the adjacent portion of the fixed switch enclosing structure and retain the head portion in position over the bolts 71 when the switch unit is in its fully raised position whereby an operator is prevented from applying a socket wrench to the bolts should he attempt to remove a tank with the unit fully raised. The head portion of each guard is heavier than the tail portion so that when the switch unit is lowered to the isolating position the guards automatically swing away from the bolts but when the unit is raised to connect it into the circuit. the tail of the guard by engaging the fixed switch casing swings the head over the bolt.

From the above description it will be observed that the several switch units have three definite positions, namely the fully raised or service position in which they are illustrated in the drawing, a partially lowered or isolated position in which the units rest on the latches 65 and the isolating contacts are separated a safe distance, and the fully lowered position when the switch unit is free to be moved about at will. The switch units as already mentioned above are electrically actuated and for the purpose of automatically connecting each unit to the source of power when it is raised into position and disconnecting it therefrom when it is lowered, I have provided the connectors now to be described. Referring to Figs. 3 and 5, cable 76 from a suitable source of operatin current terminates in the socket contact blocii 77 belng fixed to the switch enclosing casing 8. A cooperating plug contact block 78 carried by the switch unit has its contacts connected through cable 79 with the switch operating mechanism. Since it is sometimes desirable to be able to go through the operations of closing and opening the switch when it is in its partially lowered or isolated position I have mounted the contact block 77 on vertical guides 80 which allow the block 77 a limited amount of travel with the block 78, the extent of movement permitting the two contact blocks to remain in contact when the switch unit is lowered until it rests on the latches 65. When the unit is lowered beyond that point the blocks are pulled apart and the auxiliary circuit controlled thereby is inter rupted. Upon again raising the unit or a similar one, the contacts of the two blocks engage each other in the proper manner and reestablish the operating and control circuits of the switch unit. To overcome the friction of the plug and socket contacts and to insure complete engagement thereof, I have arranged the sprlng 82 above the block 78 to yieldingly force the contacts together when the unit is fully raised.

The above described switching structure is particularly adapted for an outdoor installation being entirely metal clad and on the whole of such massive and rigid construction as to be unaffected by storms, snow or ice. I prefer to provide at a point adjacent one end of the structure a building, not shown on the drawing, into which the switch units, transformers, etc. normally mounted on the outdoor structure may conveniently be taken for inspection and repair. I also provide a substation building which if desired may be combined with the aforesaid building for housing the station control and instrument boards, suitable cables being provided for connecting the boards with the operating and si nal apparatus on the outside structure. The aforesaid building for receiving the switches and transformers will have a doorway through which extends the track 58 and through which can be rolled the entire car riage 59 carrying a switch or transformer. The arrangement of station apparatus which I have provided greatly facilitates the movement thereof for since the switch units are arranged in two parallel rows extending in the longitudinal direction of the station and spaced apart a sufficient distance to allow the transversely movable part 60 of the carriage to move therebetween it will be seen that any one switch unit may be raised and lowered by use of a single carriage which can be brought up between the rows from a distant point. Furthermore, any switch unit may be lowered b the carriage, the latter shifted transverse y to the mid position and then rolled longitudinally of the station without interference with the remaining units of the two rows and into a suitable building for inspection or repair. As shown in Fig. 2, the potential transformers are mounted on the rackets 83 at the side of the supporting structure. As so arranged the transformers may be raised and lowered by means of suitable elevating mechanism, not shown, mounted on the adjacent columns or on a truck outside of the row of columns. In certain cases it may be found preferable to arrange these transformers between a row of columns and the adjacent row of switch units and electrically connected to the current transformer boxes. The potential transformer can also be mounted in the space between the switch units just below the conservators. In this case the transformers may be handled by the same carriageand in the same manner as the switch units.

In order to prevent the complete loss of oil from the armor enclosing the conductors of any phase, the armor is divided into sections by suitable partitions. The sections are supplied with oil by conservator tanks 84 of which three are shown mounted in an elevated position centrally of each bay and connected to the various sections and connection boxes by pipes 85. An air space 86 is preserved in the .top of each connection and junction box to form a cushion to prevent damage to the armor in the event of a sudden gas formation therein.

In Fig. 6 I have shown a fragmentary view looking upward of the switch housing and in Fig. 7 a cross sectional view of the same taken on the line 7-7 of Fig. 6.

The two openings 88 in the top of the switch housing over each of which stands one of the insulating shells 40 supporting an isolating contact 39 are provided with the shutters 89 for the purpose of covering them whenever the switch is lowered and the bushings withdrawn. The shutters are pivotally mounted at 90 and are connected by rods 91 and 92 to the operating lever 93 which has slots for the guide pins 94:. For operating each pair of shutters, I have provided a flat shaft 95 secured in an upright position to the switch unit and having at its upper end the twist 96. In the lever 93 is the elongated opening 97 adapted to receive the shaft 95 when the switch unit is raised toward contact position. The twist in the shaft serves to turn the lever to shift the two shutters connected therewith to the uncovering position illustrated when the switch unit is raised and conversely the shaft also turns or controls the turning movement of the shutters to the covering osition when the unit is lowered to the point where the bushings and contacts thereon clear the openings. For

the covering movement I prefer to provide in addition to the shaft the spring 98 which is arranged to move the lever 93 and theshutters to the covered position and to resiliently maintain the shutters closed while the operating shaft is withdrawn.

Referring now to the circuit diagram forming Fig. 8, the three phase system previously described is for convenience illustrated by a single line diagram. The feeder cables 6 which may be either incoming oroutgomg terminate at the current transformers 24 and become the phase conductors 20. By closing the one or the other of the two switches 36 associated therewith, each phase conductor 20 may be connected to either the main buses 9 or to the reserve buses 10. By closing both switches the feeder may be connected to both buses and the buses thereby tied together. Connected to the phase conductors 20 ,of each feeder through the fuse 28 and resistance 29 is the potential transformer 27, connections to whose secondary run to the dis-' tant instrument board. At some point in the structure, preferably at the end opposite to that illustrated in Fig. 1, I provide the potential transformers 100 which connect respectively with the main and reserve bus bars for measuring the bus potential and for synchronizing purposes.

In certain cases it may be desirable to sectionalize the bus bars and to use oil switches to connect together or separate the sections. In Fig. 9 I have shown a fragmentary diagram of a sectionalized bus bar 101 with the switch 102 between the sections. Thisswitch in the present system would be similar to the switch units 36 and be arranged in alinement therewith occupying one bay. Where it is desired to be able to connect the two adjacent bus sections by a-reactance shown at 103 and yet be able to handle the reactance, for example to inspect or replace the same without danger from the line potential, two switches 104 and 105 may be used to connect the opposite ends of the reactance with the two sections. Thus the reactor may be thrown into or out of the bus circuit or removed.

The switching station which I have described above is well adapted to be equipped with a ground bus protecting system in which case any grou of bays would be insulated from the adjoining bays and from ground. For the latter insulation a layer of insulating material may be inserted in the column, for example at its base.

I am aware that my invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore aim in the appended claims to cover changes and modifications within the true spirit and scope of my invention. I

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A polyphase switching station comprising a series of supporting columns, a fabricated switch carryin structure supported thereby, certain mem ers of said structure forming downwardly opening housings each adapted to receive from below a switch hav-- ing isolating contacts thereon, cooperating isolating contacts in the top of each housing and means comprising a plurality of cam devices within said housing for clamping the switches in position in the housings, said cam devices having a common operating member arran ed at the exterior of the housing.

2. polyphase switching station including an elevated supporting structure, a polyphase switch unit adapted to be suspended therefrom, cooperating isolating contacts on said structure and switch unit, means for simultaneously securing together the structure and switch unit at a plurality of points comprising cams operable in one position to clamp the members firmly together and in another position to permit the lowering of the unit without interference therewith, and a common actuating member for said cams.

3. A switching station including a fixed elevated structure, an oil switch including its contact operating mechanism adapted to be bodily secured thereto and to be removed therefrom, cooperating isolating contacts on said structure and switch arranged to connect with and to be disconnected from each other when the switch respectively is secured to and removed from the structure, circuit connections for said operating mechanism comprising cooperating contacts mounted respectively on the structure and on the switch, the

contact mounted on the structure having a limited movement relative thereto in the direction of movement of the switch whereby the operating mechanism may be controlled by said connections in an insolated position of the switch.

4. A switching station including an elevated supporting structure, a switch unit havin electrically operated contact mechanism ad apted to be secured thereto and to be lowered away therefrom, cooperating isolating contacts on said structure and switch unit arcontacts 011 said structure and switch unit arranged to connect with and to be disconnected from each other when the switch respectively is in its raised position and when it is lowered to an isolated position, auxiliary contact terminals on said unit connected with said mechanism, a movable contact block having cooperating contact terminals, means on said structure for guidin the block and for limiting its movement when the unit reaches said predetermined position.

In witness whereof, I have hereunto set my hand this 3rd day of February, 1928.

HERMAN J. H. HUBER.

ranged to connect with and to be disconnected

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