US3309482A - Recirculating-type gas-blast doublebreak circuit interrupter with filtering housing surrounding intermediate contact - Google Patents

Description

March 1967 w M. LEEDS 3309,42

RECIRCULATING-TYPE GAS-BLAST DOUBLE-BREAK CIRCUIT INTERRUPTER WITH FILTERING HOUSING SURROUNDING INTERMEDIATE CONTACT Filed Nov. 22, 1965 I 5 $heets $heet 1 INVENTOR Winthrop M. Leeds BY MM W ATTORNEY 3 309 482 UIT W. M. LEEDS March 14, 1967 -BREAK CIRC INTERRUPTER WITH FILTERING HOUSING SURROUNDING RECIRCULATING-TYPE GAS-BLAST DOUBLE INTERMEDIATE CONTACT 5 Sheets-Sheet 2 Filed Nov. 22, 1965 3,309,482 UIT March 14, 1967 w. M. LEEDS RECIRCULATING-TYPE GAS-BLAST DOUBLE-BREAK CIRC INTERRUPTER WITH FILTERING HOUSING SURROUNDING INTERMEDIATE CONTACT 3 $1198 tS-Sheet 3 Filed Nov. 22, 1965 g HA M g 3 mm E mm NM 6 o J N m mm Fm mm Jmm\ mm mm W U mv mm 7 1 7 f M 4; mm K United States Patent Office 3,309,482 Patented Mar. 14, 1967 RECIRCULATING-TiKPE GAS-BLAST DOUBLE- BREAK CIRCUIT INTERRUPTER WITH FIL- TERING HOUSING SURRUUNDING INTER- MEDIATE CQNTACT Winthrop M. Leeds, Forest Hills Bore, Pittsburgh, 1 21.,

assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Nov. 22, 19 65, Ser. No. 509,064 Claims. (Cl. 200-148) This application is a continuation-in-part of US, application filed Apr. 17, 1961, Ser. No. 103,651, now aban doned.

This invention relates to circuit interrupters in general, and, more particularly, to circuit interrupters of the gasblast type.

A general object of the present invention is to provide an improved, highly-effective, gas-blast circuit interrupter in which impedance means, such as resistance means, are employed to assist in the interruption of the main current are, thereby lowering the rate .of rise of the recovery voltage transient, and at the same time in which means are provided to assist in the purification of the utilized arcextinguishing gas.

In the United States Patent 3,214,553 issued to Winthrop M. Leeds, and assigned to the assignee of the instant application, there is disclosed and claimed various gas-blast types of circuit interrupters in which the arc-extinguishing gas is directed into filtering elements prior to its subsequent exhausting into the main interior of the tank structure for reuse. It is a further object of the present invention to improve upon the types of interrupting structures set forth in the aforesaid patent, rendering them more compact and more efficient in operation.

In US. Patent 3,160,726, issued Dec. 8, 1964, to Charles F. Cromer, and also assigned to the assignee of the instantapplication, there is disclosed and claimed a gas-blast interrupting unit, particularly adaptable for a high-power circuit interrupter, in which a tubular intermediate contact is co-operable with a relatively stationary main contact having a resistance shunt therebetween. A series isolating contact is employed to interrupt the residual current arc following extinction of the main break arc. It is an additional object of the present invention to extend the principles set forth in the last-mentioned patent, rendering them more applicable to a high-power circuit interrupter in conjunction with suitable filtering elements.

Further objects and advantages will readily become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

FIGURE 1 is an end elevational view of a three-pole high-power circuit interrupter embodying features of the present invention;

FIG. 2 is a substantially vertical sectional view taken through one of the tank structures of FIG. 1, illustrating the bridging arc-extinguishing assemblages, the contact structure being illustrated in the closed-circuit position;'

FIG. 3 is a considerably-enlarged view, in section, taken substantially through the righthand arc-extinguishing unit of FIG. 2, and illustrating the contact structure in the closed-circuit position;

FIG. 4 is a substantially vertical sectional view taken through the same interrupting unit, as is illustrated in FIG. 3, but the contact structure is illustrated in the fully open-circuit position; and,

FIG. 5 is a diagrammatic view of the circuit interrupter of FIGS. 1-4 illustrating the general path of the electrical circuit passing through the interrupter.

Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral generally designates a dual-pressure gas-blast type of circuit interrupter.

As shown, the circuit interrupter 10 is of the high-power type involving a group of three generally horizontally-extending grounded tank structures 11 spaced apart, and simultaneously mechanically actuated by an operating mechanism, not shown, disposed within a mechanism housing 12 situated adjacent one of the three tank structures 11.

As shown in FIG. 1, a pair of terminal bushings 13, 14 extend downwardly within each of the three tank structures 11 for carrying the circuit to an arc-extinguishing assemblage 15 (FIG. 2), which mechanically and electrically bridges the lower ends 16, 17 of the terminal bushings 13, 14, respectively.

Located adjacent the lower end of each of the three tank structures 11 is a drive-shaft 18, which passes through a .sealed gas-tight opening, not shown, externally of the tank structure 11, and is externally actuated by a suitable drive-crank 19. The three drive-cranks 19 are mechanically connected together for simultaneous operation by a mechanism, not shown, disposed within the mechanism housing 12 (FIG. 1).

With reference to FIG. 2, it will be observed that there are provided three gas-blast interrupting units, generally designated by the reference numeral 21), disposed in series for interrupting the current passing through the circuitinterrupting structure 15. The bridging arc-extinguishing assemblage 15 not only comp-rises the three gas-blast interrupting units 2%), but also it comprises a high-pressure reservoir chamber 21, disposed at the right-hand end of the extinguishing assemblage 15, as viewed in FIG. 2. To control the passage of high-pressure gas out of the highpressure reservoir chamber 21, there is provided a gasblast mechanism, generally designated by the reference numeral 22, and more particularly set forth in detail, and its function described, in United States Patent 3,164,704 issued I an. 5, 1965 to Russell N. Yeckley, Joseph Sucha and Roswell C. Van Sickle, and assigned to the assignee of the instant application. I

For the purpose of understanding the present invention, however, it is merely necessary to know that the operation of the gas-blast mechanism 22 effects opening of a blast valve 23 (FIG. 3), and permits a blast of high-pressure gas to pass from the reservoir chamber 21 through an inlet passage 24 and into the first, or right-hand interrupting unit 20 of the assemblage 15. The gas blast also blasts through a pair of blast- tubes 25, 26 and into the adjaoently-disposed gas-blast interrupting units 20' to effect extinction of the arcs therein.

An insulating feed conduit 27 feeds high-pressure gas from an externally-provided compressor disposed within the mechanism compartment pressure storage tank 21 in each of the three tank structures 11 to replenish the high-pressure gas which is used up 1czuring the opening operations of the circuit interrupter Mechanically interconnecting an internal crank-arm 28, afiixed to the drive-shaft 18, with the gas-blast valve operating mechanism 22 is an insulating operating rod 29. In addition, the operating rod 29 mechanically operates a movable contact assemblage, generally designated by the reference numeral 30, and comprising a pair of longitudinally-extending operating rods 31 bridged by transverse cross-bars 3-2 carrying movable disconnecting contacts 33 adjacent the middle portions thereof.

As illustrated in FIGS. 3 and 4, the movable disconnecting contact 33 of each gas-blast interrupting unit 20 engages a tubular intermediate contact 34, which moves with the disconnecting contact 33 toward the end of the closing operation. As illustrated in FIG. 3, the disconnecting contact 33 forces the movable tubular intermediate contact 34 into contacting engagement with a relatively stationary contact, generally designated by the ref- 12 (FIG. 1 to the high- I (3 erence numeral 35. A biasing spring 36, which may comprise a battery of individual springs 33a, biases the tubular movable intermediate contact 34 toward the open-circuit position, as shown in FIG. 4.

As illustrated in both FIGS. 3 and 4, the relatively stationary contact structure 35, comprises a plurality of ann-ularly-dis-posed segmental flexible contact fingers 37 and a substantially centrally-disposed arcing horn 38. During the opening operation, a main current are 39, illustrated in FIG. 4, is drawn between the relatively stationary contact structure 35 and the movable tubular intermediate contact 34. This main are 39 is shunted by an impedance means 40, in this particular instance comprising a resistance 41. Preferably, the resistance 41 is in the form of a helically-shaped coil of high-resistance coiled wire. The resistance 41 is supported by a plurality of annularly-disposed insulating support rods 42, which are supported by a bracket 43 from the end casting 44 at one end, and at the other end by an electrostatic metallic shield 44a. A flexible shunt 45 electrically interconnects the left-hand end of the resistance coil 41 with a resistor terminal 46, which constitutes an integral part of a relatively stationary metallic filter housing 47, containing a suitable filtering material 48. Preferably the filtering material 48 comprises suitable mesh screening and preferably, in the case of sulfur-hexafiuoride (SP gas, activated alumina.

Preferably the metallic filter housing 47 constitutes a guiding means for movement of the intermediate tubularshaped contact 34 and also provides a spring seat for the intermediate contact compression spring 36. It is supported from a pair of spaced-apart stationary insulating tie-bars 67 by means of insulating cross-bars as of generally T-shape. Bolts 68a fixedly secure the several crossbraces 68 to the left hand ends of the filter housings 4-7, as shown more clearly in FIG. 4.

To assist in directing the released gas blast from the high-pressure chamber 21 by opening of the blast valve 23, an insulating flow director 49 is provided. As illustrated more particularly in FIG. 4, the flow director 49 directs the gas blast within the interior 50 of the movable tubular intermediate contact 34. The intermediate contact 34 is provided with side venting ports 51, which direct all the arced gas into the filter housing 47, and thereby compel all the same to be purified prior to ultimate exhaust into the general interior 52 within the main body of the tank structure 11.

As well known by those skilled in the art, the provision of the shunting impedance 40 assists in the interruption of the main current are 39 and improves the power factor of the circuit, while at the same time lowering the rate of rise of the circuit to be interrupted. The residual current arc 53 is interrupted at the series isolating gap comprising the disconnecting contact 33 and the arc-horn portion 54 of the intermediate contact 34.

Although FIG. 4 illustrates the fully open-circuit position of the several contact parts, nevertheless, for purposes of illustration, the main current are 39 and the residual current are 53 have been drawn into the figure for the purpose of clarifying the description of the opening operation of the interrupter.

It will be observed that the movable disconnecting contact 33 comprises an annularly-disposed finger cluster 55, and an interiorly-disposed finger cluster 56. In the closedcircuit position, as shown in FIG. 3, the annularlydisposed fingers 55, 56 make contacting engagement with similar fingers 57 constituting an end portion of the intermediate contact 34.

FIG. diagrammatically illustrates the electrical circuit passing through the tank structure 11. The movable contacts 34, 35 which open first are designated by the reference numeral 1. The series disconnecting contacts 33, 34, which open subsequently to the opening of the main contacts 1 are, in FIG. 5, designated by the reference numeral 2. With reference to FIG. 5, it will be apparent that opening of all of the main breaks 1 will cause the circuit to pass through the shunting resistance sections R, and following opening of the disconnecting contacts 2 will interrupt the residual current passing through the resistance sections 41, which is of lower amperage and of a higher power factor than the main current arcs .39.

In the closed-circuit position of the interrupter 19, illustratecl in FIGS. 2 and 3, it will be apparent that the circuit through the interrupter comprises terminal bushings 13, 14, end clamps 16, 17, and the several interrupting units 2a, each of which passes the current through the disconnecting contacts 33, intermediate contact 34, to the stationary contact 35 thereof.

A battery of accelerating compression springs 58 (FIG. 2) is provided to effect leftward opening biasing action upon the movable contact assemblage 30. When the mechanism within mechanism housing 12 (FIG. 1) is released or unlatched, the several insulating operating rods 29 have their tensile stress released, and the accelerating spring 58 in each of the tank structures 11 take over, and very quickly effect leftward opening movement of the several movable contact assemblages 31). With reference to FIG. 4, it will be noted that the leftward opening movement of each of the movable disconnecting contacts 33 will permit the battery of compression springs 36, associated with each gas-blast interrupting unit 21), to force the movable tubular intermediate contact 34 into following engagement with the disconnecting contact 33, thereby effecting a separation between the tip end 59 of intermediate contact 34 and the contact fingers 37. This will draw a main current arc 39 shown in F116. 4. Simultaneously with the leftward opening movement of the movable contact assemblies 30, the blast-valve mechanism 22 is actuated to cause thereby clockwise rotation of a pivotallymounted blast-valve lever 59, as set forth in aforesaid Patent 3,164,704, to open the blast valve 23, and to let the resulting gas blast carry the main current arc 39 inwardly to terminate upon the arcing horn 38. The gas blast moves the left-hand terminal of the are 39, as viewed in FIG. 4, along the inner surface 60 of the movable tubular intermediate contact 34 in a manner more fully explained in the United States Patent 3,154,658 issued Oct. 27, 1964, to Robert G. Colclaser, In, and Russell N. Yeckley, and assigned to the assignee of the instant application.

Because of the provision of the shunting impedance 40, and also because of the intensive gas blast, directed by the flow director 49 interiorly within the region 50 of the intermediate contact 34, the main-current arc 39 is quickly extinguished, all of the gas blast, following arc, passing through the lateral port openings 51 and into the filter housing 47.

When the flange portion 61 of the intermediate contact 34 strikes the stop as constituting the left-hand wall of the filter housing 47, as viewed in FIG. 4, the intermediate contact 34 will be halted in its leftward opening movement, thereby permitting the movable disconnecting contact 33 to pull away from it, and to draw a relatively small-amperage residual-current arc 53. This are 53 has a low amperage, and at this time the circuit has a relatively high power factor. Consequently, the are 53 is easily interrupted. Continued opening movement of the movable disconnecting contact 33 results in interposing a series isolating gap into the circuit to thereby enable the circuit interrupter 10 to withstand surge voltages, such as lightning surges in the fully open-circuit position of the interrupter 10.

It will be observed that the provision of the filter housing 47 compels all of the sulfur-hexafiuoride (SP gas to pass through the filtering materials 43 prior to subsequent exhaust into the general interior 52 of the tank 11.

It is particularly important to catch metallic fluoride powders with screens or filters, since these powders, although good insulation when dry, are hydroscopic and take up moisture very easily when, for instance, a breaker is opened for inspection of the contacts. However, the activated alumina which is provided to purify the gas of active gaseous are products could alternatively be placed in other locations in the tank where its purifying function could take place over a somewhat lower period of time, as indicated by the filter container 470.

It is well known that resistors of the proper magnitude placed in parallel with the arcing contacts of a power circuit breaker aid the interruption of short-circuit currents by controlling the rate of rise of recovery voltage. The present invention is, in part, concerned with novel sulfur-hexatluoride breaker arrangements for using resistors, in combination with flow channels for the gas, which are directed through screens and filters. Although the present invention has been described in connection with the particular use of sulfur-hexafluoride (SP gas as the arc-extinguishing gas, it is to be clearly understood that the invention is not limited solely to this particular gas alone, but may be employed with any other gas, which needs purification prior to subsequent reuse.

The power circuit breaker 10, shown in FIGS. 1-4 of the drawings, illustrates a 230 kv., SF dead tank breaker constructed to incorporate the use of a shunting resistance 41 and the additional use of a filtering element 47. It is to be emphasized that the provision of a special exhaust chamber 47 with screens and a filter 48 is very desirable to clean up the arced SP gas before it is released into the main low-pressure tank 11, where the insulating parts are located. Particular advantages of the construction illustrated in FIG. 2 are that fewer main breaks are required, and filtering of the are products is obtained to keep the breaker clean.

To effect the closing of the circuit interrupter 10, the mechanism, not shown, disposed within the mechanism housing 12 is effective to cause, through suitable linkage, not shown, counterclockwise rotative closing motion of the several external crank-arms 19, shown in FIG. 2. The counterclockwise rotation of the several crank-arms 19 effects corresponding counterclockwise rotation of the several drive shafts 18 and consequently generally leftward closing movement of the insulating operating rods 29. Since the right-hand ends of the insulating operating rods 29 are connected, as at 66 (FIG. 3) to a crank-arm 67 pivotally mounted on a fixed pivot axis 68, a floating link 69, pivotally connected, as at 70, to the crank-arm 67 is effective to effect rightward closing movement of the two insulating operating rods 31 of the movable contact assemblage 30. This closing movement of the several movable contacts 33 will charge the accelerating spring 58 and also effect contact closure, first at the contact breaks 33, 57 and subsequently at the main breaks 59, 37. Reference may be had to United States Patent 3,057,983, issued Oct. 9, 1962, to Russell N. Yeckley, Joseph Sucha and Benjamin P. Baker and assigned to the assignee of the instant application for further details of operation of the interrupter 10.

From the foregoing description of an interrupting structure embodying features of the present invention, it will be apparent that there is provided a novel circuit-interrupting structure, in which impedance means are employed to shunt the main breaks; and subsequently, the residual current through the impedance means is interrupted at resistance breaks.

Although there has been illustrated and described a specific structure, it is to be clearly understood that the same Was merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the invention.

I claim as my invention:

1. A gas-blast circuit interrupter of the recirculatinggas type including a relatively stationary contact, a movable tubular intermediate contact through which gas may flow and a movable disconnecting contact cooperable with said movable intermediate contact to establish an isolating break, means for directing a flow of compressed gas into the movable tubular intermediate contact during the opening operation to extinguish the are established between the relatively stationary and intermediate contacts, a filter housing substantially surrounding the tubular intermediate contact, and venting means (51) provided in the side Wall of the movable tubular intermediate contact for directing all of the gas flow into the surrounding filter housing prior to exhaust for subsequent reuse.

2. The recirculating gas-blast circuit interrupter of claim 1, wherein a biasing spring for the movable tubular intermediate contact is seated within said filter housing.

3. The recirculating gas-blast circuit interrupter of claim 1, wherein the filter housing guides the opening and closing movement of the movable tubular intermediate contact. v

4. The recirculating gas-blast circuit interrupter of claim 1, wherein an insulating flow director (49) directs all of the gas flow into the interior of the movable tubular intermediate contact to carry one terminal of the established main current are thereinto.

5. The combination according to claim 3, wherein impedance means shunts the stationary and intermediate contacts, and the filter housing serves as a terminal for one end of the impedance means.

References Cited by the Examiner UNITED STATES PATENTS 2,125,525 8/1938 Thommen 200-148 3,160,726 12/1964 Cromer 200- X 3,164,705 1/1965 Cromer 200148 3,221,129 11/1965 Young 200148 ROBERT K. SCHAEFER, Primary Examiner. ROBERT S. MACON, Examiner.

Claims (1)

1. A GAS-BLAST CIRCUIT INTERRUPTER OF THE RECIRCULATINGGAS TYPE INCLUDING A RELATIVELY STATIONARY CONTACT, A MOVABLE TUBULAR INTERMEDIATE CONTACT THROUGH WHICH GAS MAY FLOW AND A MOVABLE DISCONNECTING CONTACT COOPERABLE WITH SAID MOVABLE INTERMEDIATE CONTACT TO ESTABLISH AN ISOLATING BREAK, MEANS FOR DIRECTING A FLOW OF COMPRESSED GAS INTO THE MOVABLE TUBULAR INTERMEDIATE CONTACT DURING THE OPENING OPERATION TO EXTINGUISH THE ARC ESTABLISHED BE-

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