US3513277A

US3513277A - Electric circuit breaker comprising series-connected interrupting units

Info

Publication number: US3513277A
Application number: US705040A
Authority: US
Inventors: Philip Sciscione
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1968-02-13
Filing date: 1968-02-13
Publication date: 1970-05-19
Anticipated expiration: 1987-05-19

Description

P. SCISCIONE May 19, 1970 ELECTRIC CIRCUIT BREAKER COMPRISING SERIES-CONNECT INTERRUPTING UNITS 3 Sheets-Sheet 1 Filed Feb. 15, 1968 //v VE/VTOR. PH/L/P Some/0N5,

ATTORNEY May 19, 1970 P. SCISCIONE' 4 3, ELECTRIC CIRCUIT BREAKER COMPRISING SERIES-CONNECTED INTERRUPTING UNITS Filed Feb. 13, 1968 3 Sheets-Sheet 2 C/RCU/T BREAKER OPE/V //v VENTOR. PHIL/P SC/SC/ONE,

5) ATTORNEY May 19, 1970 P. SCISCIONE 3,513,277 ELECTRIC CIRCUIT BREAKER COMPRISING SERIES-CONNECTED INTERRUPTING UNITS 3 Sheets-Sheet 3 'Filed Feb. 13, 1968 ATTORNEY United States Patent.

3,513,277 ELECTRIC CIRCUIT BREAKER COMPRISING SERIES-CONNECTED INTERRUPTING UNITS Philip Sciscione, Havertown, Pa., assignor to General Electric Company, a corporation of New York Filed Feb. 13, 1968, Ser. No. 705,040 Int. Cl. H01h 33/86 US. Cl. 200-148 8 Claims ABSTRACT OF THE DISCLOSURE A high voltage circuit breaker comprising spaced-apart high voltage enclosures respectively mounted atop horizontally spaced-apart insulators, circuit interrupters within the enclosures, and control valves at high voltage respectively located adjacent the interrupters for controlling their operation. A hollow insulating housing extends between the enclosures in the high voltage region of the breaker; and a linkage interconnecting the valves is located within said insulating housing. The valves are simultaneously operated through said linkage by a single operating rod extending between the linkage and motive means at ground potential.

This invention relates to an electric circuit breaker of the type which comprises a plurality of series-connected interrupting units respectively housed in enclosures that are at a high voltage with respect to ground.

In the circuit breaker that I am concerned with, these interrupting units are required to operate substantially simultaneously. For effecting such simultaneous operation, it is customary to provide a control element adjacent each interrupting unit and to interconnect the control elements with a mechanical linkage coupled to a common operator for the control elements. Typically, this mechanical linkage comprises, for each control element, an operating rod of organic insulation that extends in a vertical direction to ground through the insulating column that supports the high voltage enclosure. These vertical operating rods are typically connected together at their lower ends by a portion of the linkage that is at ground potential, and to this portion of the' linkage the common operator is coupled. An example of such a linkage is shown and claimed in US. Pat. No. 3,333,071-Oppel et al., assigned to the assignee of the present invention.

Linkages of this type are subject to a number of disadvantages. One is that they are so long that it is difficult to synchronize motion of their remote ends with the desired high degree of precision. Another is that they present a multiplicity of possible breakdown paths along organic insulation between the high voltage portions of the circuit breaker and ground.

An object of my invention is to construct the linkage in such a manner that its effective length is shorter than that of prior designs and it presents fewer possible breakdown paths to ground along organic insulation.

Another object is to so locate the linkage that it is easily accessible and does not require space within the support columns of the circuit breaker.

In carrying out the invention in one form, I provide a high voltage circuit breaker comprising a plurality of spaced-apart enclosures at a high voltage with respect to ground and a plurality of horizontally spaced-apart insulating structures on which said enclosures are respectively mounted. Within the enclosures, a plurality of circuit-interrupting means are respectively located. A plurality of control valves at high voltage are respectively located adjacent the interrupting means for controlling the operation of the associated interrupting means. A

hollow housing primarily of insulating material extends between said high voltage enclosures in the high voltage region of the circuit breaker. Linkage means located within this housing mechanically interconnects the control valves. A vertical insulating operating rod coupled at its upper end to the linkage means extends to a point at ground potential at its lower end, and motive means is provided for applying an operating force to said lower end for operating the control valves substantially simultaneously through said linkage means.

BRIEF DESCRIPTION OF DRAWINGS For a better understanding of the invention, reference may be had to the following description taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevational view of a circuit breaker assembly embodying one form of our invention.

FIG. 1a is a schematic illustration of part of the circuit breaker of FIG. 1 including as a portion a sectional view along the line 1a1a of FIG. 1. In this figure the circuit breaker is shown in its open position.

FIG. 2 comprises a similar sectional view of the circuit breaker of FIG. 1 but showing the circuit breaker in its closed position. FIG. 2 additionally comprises a sectional view of a portion of the circuit breaker of FIG. 1 taken in a plane parallel to the paper in FIG. 1.

Referring now to FIG. 1, there is shown a high voltage circuit breaker comprising two substantially identical circuit breaker units 11a and 1112 connected in series in a power circuit 25. Each circuit breaker unit comprises a metal tank 14 at a high voltage with respect to ground and an insulating column 15 supporting the metal tank and electrically isolating it from ground. The insulating columns 15 are horizontally spaced-apart. Disposed within each tank is an interrupting unit of any suitable type, for example, of the type shown and claimed in the aforesaid U.S. Pat. No. 2,783,338-Beatty. Since the details of the interrupting unit form no part of the present invention, most of them are not shown. In FIG. 1a and 2, a block 20 has been used to denote the operating mechanism of the illustrated interrupting unit.

Each interrupting unit comprises two pairs of relative ly

movable contacts

21, 22 and 23, 24 connected in series in power circuit 25 extending therethrough. The stationary contact of each pair of contacts is supported on the conductive stud of a terminal bushing 26 projecting into tank 14. The bushing electrically isolates the stationary contact from the tank 14 when the contacts are open, as shown in FIG. 1. The adjacent bushings 26 have high voltage conductors 25b that connect the interrupting means together electrically in series in the high voltage circuit 25. A flexible conductor 25a electricity interconnects the adjacent high voltage conductors 25b. The movable contact of these pairs of contacts is connected to the common operating mechanism 20 by links schematically designated in FIG. 1a. When operating mechanism 20 operates during a closing operation, it drives

movable contacts

21 and 23 into closed position substantially simultaneously. During an opening operation, mechanism 20 drives

contacts

21 and 23 into their open position substantially simultaneously.

Tank 14 contains a high pressure gas, and this is used for electrical insulation and for operating the mechanism 20. For controlling mechanism 20, a control valve 30, shown in simplified schematic form in FIGS. 1a and 2, is provided in a control conduit 32 interconnecting the pressurized interior of tank 14 and operating mechanism 20. This control valve 30 comprises a movable valve element 34 that is movable between two positions, one of which is shown in FIG. 1a and the other in FIG. 2. When in the position of FIG. la, the valve element 34 permits communication between the interior of tank 14 and conduit 32 via an inlet port 33 in the valve housing 36. In the position of FIG. 1a, the movable valve element 34 also abuts against a seat 37 at the upper end of the valve housing and thus prevents pressurized fluid from flowing into a vent passage 38 from either the tank 14 or operating mechanism 20. When movable valve element 34 is operated into its position of FIG. 2, it abuts against the seal 39 and thus blocks communication between the interior of tank 14 and operating mechanism 20. When valve element 34 is in this position of FIG. 2, a vent port 41 aflords communication between vent passage 38 and control conduit 32, thus venting operating mechanism 20.

When control valve 30 is in its open position of FIG. 1a, operating mechanism 20 is under pressure and thus holds the contacts open in the manner shown in the aforesaid Beatty patent. When control valve 30 is operated to its position of FIG. 2, operating mechanism 20 is vented, and suitable biasing means operates the contacts to their closed position in the manner disclosed in the aforesaid Beatty patent.

As pointed out hereinabove, I am concerned with the type of circuit breaker in which widely spaced interrupting units are required to operate substantially simultaneously. For example, in the illustrated circuit breaker, the interrupting units in the series-connected circuit breaker units 11a and 11b are required to operate substantially simultaneously, both during circuit-breaker-opening and during circuit-breaker-closing. For effecting the desired simultaneous operation of the operating units, I interconnect the movable control valve elements 34 by means of a linkage 40. This linkage 40 comprises four basic portions: (1) a linkage portion 40a connected to the control valve in circuit breaker unit 11a and extending between this control valve and a centrally-disposed casing 42; (2) a substantially identical linkage portion 40b connected to the control valve in circuit breaker unit 1111 and extending between this control valve and centrally-disposed casing 42; (3) a force-equalizing coupling 44 joining lileage portions 40a and 40b together; and (4) vertically-extending operating rod 46 of organic insulating material extending between the force-equalizing coupling 44 and a fluid motor 48 at the lower end of the operating rod.

Referring to FIG. 2, this linkage 40 is enclosed by a T-shaped housing 47 which comprises major components of insulating material. This T-shaped housing 47 comprises a vertically extending tubular insulating column 148 surrounding vertical operating rod 46 and a metal casing 42 mounted atop column 148. Projecting horizontally from casing 42 are two tubular sub-housings 49a and 49b, prirnarly of insulating material, which surround linkage portions 40a and 40b, respectively. Each of these tubular subhousings communicates at one end with the central casing 42 and at its other end with the interior of associated tank 14. The interior of the T-shaped housing 47 is therefore filled with gas at the same pressure as the gas inside tanks 14. The sub-housings 49a, 4% may be thought of as forming a hollow housing that extends between enclosures 14 in the high voltage region of the circuit breaker.

Referring to FIGS. la and 2, the linkage portion 40a comprises a valve actuating rod 50a, a first bell crank 51a, an insulating tie rod 52a, a second bell crank 54a, and a tie link 55a. The first bell crank 51a is mounted on a stationary pivot 53a carried by tank 14 and a second bell crank 54a is mounted on a stationary pivot 56a carried by central casing 4'2. The valve actuating rod 50a is suitably connected at one of its ends to the movable valve element 34 and at its other end to one arm of the first bell crank 51a. Insulating tie rod 52a is pivotally connected at its respective opposite ends to the other end of first bell crank 51a and to one arm of second bell crank 54a. The other arm of bell crank 54a is pivotally connected to the upper end of tie link 55a.

Since the other linkage portion 40b is substantially identical to 40a, it will not be described; but corresponding parts thereof are designated with reference numerals corresponding to those used on linkage 40a, except with the suffix b instead of a.

As shown in FIG. 2, the two linkage portions 40a and 40b are connected together by means of a force-equalizing coupling 44'. This coupling comprises a floating, forceequalizing member 60 to which the vertical operating rod 46 is pivotally connected at a centrally-disposed location 61. The linkage portions 40:: and 4012 are pivotally connected to the force-equalizing member 60 at points 62 and 64 spaced equidistant from the operating rod connection at 61. The operation of force-equalizing coupling 44 is explained in greater detail in concurrently-filed application Ser. No. 705,044-Sciscione et al., assigned to the assignee of the present invention.

Vertical operating rod 46 extends between force-equalizing coupling 44 and a fluid motor 48 at its lower end. This operating rod 46 is, for the most part, formed of a high strength organic insulating material, e.g., epoxy resin reinforced with glass fibres.

Fluid motor 48 comprises a piston 70 fixed to the lower end of operating rod 46 and slidably mounted in an operating cylinder 72. Piston 70 has an integral extension in the form of rod 74 extending downwardly therefrom through an opening 75 in the lower end wall of cylinder 72. Extension rod 74 is slidably mounted in opening 75, and a suitable seal surrounds rod 74 to prevent leakage through opening 75. Extension 74 is exposed to the surrounding atmosphere at its lower end, thus reducing the effective area of thelower face of piston 70 by an amount equal to the cross sectional area of opening 75.

Since T-shaped housing 47 is filled with pressurized gas, it will be apparent that there is always a fluid pressure force acting downwardly on piston 70. This downward force is present even if equal pressures are present on opposite sides of piston 70 in view of the pistons smaller effective area on its lower face than on its upper face.

For controlling the position of piston 70, a three-way main control valve (FIG. 2) is provided. When the circuit breaker is in its closed position of FIG. 2, the space beneath piston 70 is vented to atmosphere through valve 80. But when valve 80 is operated into its dotted line position, the vent to atmosphere is closed, and high pressure gas flows through a supply line 82 into the cylinder space beneath piston 70. Preferably, this pressurized gas is obtained from a source that is at the same pressure as the gas in housing 47.

CIRCUIT BREAKER OPENING A circuit-breaker-opening operation is initiated by operating main control valve 80 from its solid line to its dotted line position of FIG. 2. As pointed out hereinabove, this equalizes the pressure on both sides of piston 70 and reduces the downward fluid pressure force acting thereon. This reduction in downward force on piston 70 allows an opposing force acting on the movable control valve elements 34 in tanks 14 to predominate and to drive valve elements 34 from their position of FIG. 2 to their position of FIG. 1a. This opposing force acting on each movable control valve element 34 results from the high pressure gas in tank 14 acting against the lower surfaces 82 of the movable valve element 34. This force urges movable valve element 34 toward its position of FIG. 1a, but such motion is prevented when the circuit breaker is closed by the downward force normally acting on piston 70. When this downward force is reduced, as above-described, the fluid pressure force on the movable valve elements 34 is able to predominate and drive the movable elements 34 from their position of FIG. 2 to that of FIG. 1a. This opens the circuit breaker as was described hereinabove.

CIRCUIT BREAKER CLOSING Circuit-breaker closing from the open position of FIG. 1a is effected by reversely operating main control valve 80 to vent the space beneath piston 70. This rapidly increases the net force acting downwardly on piston 70', thereby driving piston 70 and operating rod 46 downwardly. This motion is transmitted through force-equalizing member 60 and linkages 40a, 40b to movable control valve elements 34. This drives movable valve elements 34 downwardly from the position of FIG. 1a to the position of FIG. 2. This valve movement vents the operating mechanism 20, as previously explained, thus causing it to close the

contacts

21, 23, as desired.

A factor that contributes to improved synchronization between the control valve elements 34 is that the effective length of the mechanical linkage interconnecting the control valves is relatively short. In this respect, note that the connecting linkages 40a, 40b, extends between the valve elements at the high voltage level of the circuit breaker. Its elfective length is approximately the straight line distance between the valve elements. This is much shorter than in most prior designs, where, typically, the connecting linkage has comprised a vertical operating rod for each control valve and a linkage portion at ground potential interconnecting the lower ends of the vertical rods. The effective length of such a connecting linkage thus comprises the length of the vertical operating rods plus that of the linkage portion between the lower ends of the operating rods. By connecting the valve elements by a linkage located at the high voltage level, I am able to eliminate the component of length attributable to the vertical operating rods.

Another advantage of my linkage is that it contains a reduced number of possible breakdown paths along organic insulation between the high voltage portion of the circuit breaker and ground. Only a single such path, i.e., along operating rod 46, is present in my design. But in prior designs, where there have been a plurality of vertical operating rods, there have been a plurality of such possible breakdown paths ground, i.e., one for each vertical operating rod.

Since the vertical operating rod 46 is located outside the insulating support columns of FIG. 1, it will be apparent that no space for this rod needs to be provided within the support columns, thus contributing to a reduced diameter of these columns. This location outside the support column also makes the linkage more accessible in that it is not necessary to disturb the support column to obtain access to the linkage.

The housing 47 also serves as the supply conduit for supplying high pressure air to the two tanks 14. This eliminates the need for providing separate conduits within the support columns 15. This contributes to a further reduction in the diameter of the support columns and eliminates the need for special seals which heretofore had to be provided between the supply conduits and the interior of the support columns.

There is a possibility that one enclosure 14 can shift slightly with respect to the other enclosure 14, due to wind loads, thermal expansion, or unequal settling. To permit such shifting without damage to the housing 47, I provide universal joints 100 in each of the sub-housings 49a and 4%. Referring to FIG. 2, each of these universal joints comprises a tubular flanged member 102 and a tubular external member 104 surrounding the flange on member 102. There is a relatively large radial clearance space between members 102 and 104 and an annular sealing ring 107 is disposed in this space in a suitable groove in the outer periphery of the flange on member 102. A cap 109 of L-shaped cross section threaded on the exterior of member 104 holds the parts in assembled relationship.

The radial clearance in the universal joint l00 permits limited relative motion of the parts 102 and 104 in all directions, thereby permitting the enclosures 14 to shift slightly relative to each other in any direction, as

the occasion may demand, without damaging the housing 47.

An additional universal joint 100 of substantially this same construction is provided between the upper end of column 148 and the casing 42 to permit slight shifting and misalignment of the casing 42 with respect to the column 148 without transmitting harmful stresses to the poreclain of column 148.

For preventing unintended operation of a control valve element 34 in response to shifting of one enclosure 14 relative to another, the linkage 40 is provided with compensating means incorporated in the force-equalizing coupling 44. The manner in which the force-equalizing coupling 44 effects such compensating action is explained in detail in concurrently-filed application Ser. No. 705,044 Sciscione et al., assigned to the assignee of the present invention; and reference may be had thereto for more information concerning this matter. The constructional details of the linkage are claimed in the aforesaid Sciscione et al. application.

Although my invention is illustrated in a circuit breaker that has two circuit interrupters in series, it is to be understood that it is also applicable to circuit breakers with more interrupters in series. For example, the aforesaid application Ser. No. 5,044Sciscione et a1. shows the invention applied to a circuit breaker comprising three series-connected interrupters respectively housed in three high voltage enclosures, each enclosure being separately supported on its own insulating column.

While I have shown and described a particular embodiment of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from my invention in its broader aspects; and I, therefore, intend in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

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

1. A high voltage circuit breaker comprising:

(a) a plurality of horizontally spaced-apart insulating structures,

(b) a plurality of spaced-apart enclosures at a high voltage with respect to ground respectively mounted atop said insulating structures,

(c) a plurality of circuit interrupting means respectively located within said plurality of enclosures,

(d) a plurality of control valves at high voltage respectively located adjacent said plurality of circuit interrupting means for controlling the operation of the associated interrupting means,

(e) a hollow housing primarily of insulating material extending between said high voltage enclosures in the high voltage region of said circuit breaker,

(f) linkage means located within said housing and mechanically interconnecting said control valves,

(g) a generally vertical operating rod of insulating material coupled at its upper end to said linkage means and extending to a point at substantially ground potential at its lower end, and

(h) motive means for applying an operating force to said lower end of the operating rod for operating said control valves substantially simultaneously through said linkage means.

2. The circuit breaker of claim 1 in which said hollow housing comprises at least one universal joint which permits said enclosures to shift in any direction relative to each other without damaging said housing.

3. The circuit breaker of claim 2 in which said hollow housing comprises:

(a) an additional hollowportion primarily of insulating material surrounding said vertical operating rod and (b) an additional universal joint located between said additional housing portion and the housing portion extending between said high voltage enclosures which permits relative shifting of said two housing portions without overstressing the insulation of either housing portion.

4. The circuit breaker of claim 1 in which:

(a) generally horizontally extending terminal bushings are provided at one side of each enclosure for connecting the associated interrupting means in series with the other interrupting means in the high voltage circuit being controlled, and

(b) said hollow housing extends between said enclosures alongside and spaced from said terminal bushings.

5. The circuit breaker of claim 1 in which:

(a) said hollow housing comprises an additional hollow portion surrounding said vertical operating rod,

7 (b) means is provided to afford communication between the interior of said housing and said high voltage enclosures, and

(c) a source of high pressure gas communicates with said additional hollow portion at its lower end to permit said housing to act as a supply conduit between said source and said enclosures.

6. The circuit breaker of claim in which said hollow housing including said additional hollow portion is external to and spaced from said insulating structures on which said enclosures are mounted.

7. A high voltage circuit breaker comprising:

(a) a plurality of horizontally spaced-apart insulating structures,

(c) a plurality of circuit interrupting means respectively located within said plurality of enclosures, (d) a plurality of control valves at high voltage respectively located adjacent said plurality of circuit interrupting means for controlling the operation of the associated interrupting means,

(f) linkage means located within said housing and mechanically interconnecting said control valves, (g) linkage control means within said housing actuatable to cause said linkage means to operate said control valves substantially simultaneously,

(h) a generally vertical operating rod of insulating material coupled at its upper end to said linkage control means and extending to a point at substantially ground potential at its lower end, and

(i) motive means for applying an operating force to said lower end of said operating rod for actuating said linkage control means to effect substantially simultaneous operation of said control valves.

8. The circuit breaker of claim 7 in which:

References Cited UNITED STATES PATENTS 2,558,757 7/1951 Jansson 200148.6 2,824,196 2/ 1958 Thommen 200- 2,878,331 3/1959 Fjellstedt 20048 3,256,414 6/ 1966 Giammona et al. 3,350,519 10/1967 Badey et a1. 200148X 3,390,239 6/ 1968 Miller 200-145 X ROBERT S. MACON, Primary Examiner US. Cl. X.R. 200-445