US2794870A

US2794870A - Disconnect switch for high voltage lines

Info

Publication number: US2794870A
Application number: US521284A
Authority: US
Inventors: Thommen Hans; Butz Lothar
Original assignee: BBC Brown Boveri France SA
Current assignee: BBC Brown Boveri AG Germany; BBC Brown Boveri France SA
Priority date: 1954-07-13
Filing date: 1955-07-11
Publication date: 1957-06-04
Anticipated expiration: 1974-06-04
Also published as: DE1043455B; FR1128894A; BE539804A; CH322040A

Description

June 4, 1957 H. THOMMEN E'IAL 2,794,870

DISCONNECT .SWITCH FOR HIGH VOLTAGE LINES Filed July 11, 1955 2 Sheets-Sheet 1 IN VENT ORS ATTORNEYS June 4, 1957 THQMMEN. r 2,794,870

DISCONNECT SWITCH FOR HIGH VOLTAGE LINES Filed July 11, 1955 2 Sheets-Sheet 2 15 Li a INVENTOR'S 1 JW& J /Jaw ATTORNEYS Unite States Patent t'fice 2,794,870 Fatented June 4, 1957 DISCONNECT SWITQH FOR HIGH VOLTAGE LINES Hans Thommen, Baden, and Lothar Butz, Nussbaumen,

near Baden, Switzerland, assignors to A ktiengesellschaft Brown, Boveri & Cie, Baden, Swrtaerland, a joint stock company Application July 11, 1955, Serial No. 521,284

Claims priority, application Switzerland July 13, 1954 13 Claims. (Cl. 200-48) become known to date have the disadvantage that a reliable closing of the switch contacts cannot be insured under all conditions, namely as a result of a change of position of the fixed countercontact during operation. This is the case especially with overhead lines where, through wind pressure, temperature variations, ice formation, etc. considerable changes of position of the line carrying the countercontact may occur. To eliminate this disadvantage, a variety of contact arrangements have been proposed, but they are complicated and accordingly high in cost, and moreover, difiiculties arise in connection with their operation. Also, a reliable interception of the fixed, countercontact can be achieved only by a design of the movable contact such that the spatialextent of the latter during the closing movement becomes inadmissably big.

The invention relates to a high voltage disconnector of the column type for which a reliable closing of the switch is made possible in a very simple manner. According to the invention, this is achieved in that the movable contact is suspended from the high voltage line while the fixed, countercontact is located on the lower supporting insulator of the disconnector, so that the contact connection occurs through a movement from the top down.

The invention will be further explained with reference to the drawing, diiferent examples of a disconnector according to the invention being shown diagrammatically in Figures 1 to 4.

In all embodiments the movable i. e. lowerable contact is suspended from a line 1 of an upper collector bar or overhead system, while the fixed countercontact is located on the supporting insulator 2 of the disconnector.

In Fig. 1 there is illustrated an embodiment for the disconnector, or disconnect switch as it is also called, wherein the movable, lowerable contact is constituted by an electrically conductive weight 3 which is suspended from the line cable 1 by means of a flexible, electrically conductive cable which is arranged to be wound and unwound on a drum 4 carried by a support 9. The drum 4 is driven in the desired direction to raise or lower the weight 3 by means of transmission gearing driven by suitable means and having gears indicated by numeral 6. The upper end of the cable 5 is electrically connected to the line cable by suitable means, not shown, andthe weight 3 is adapted to engage the fixed, countercontact member 3a on the supporting insulator 2 as it is lowered by unwinding the cable 5 from drum 4. As previously indicated, the line 1 is subject to swinging motions attributable to various causes with the result that it becomes desirable to assure engagement between the contact members 3, 3a notwithstanding any swinging, pendulum like motion of the weight contact 3 due to motions of the line which are transmitted to the weight contact 3 through the flexible cable 5. To this end it will be observed that complementary configured, coengageable frusto-conical male and female frame elements 7, 8 are associated respectively wit-h the weight contact 3 and the fixed contact 3a such that the weight contact 3 will always be guided into direction position over the fixed contact member 3a as the former is lowered into proximity with the latter. In Fig. 1 the disconnect switch is shown with the contact members 3, 3a in engaged position thus establishing an electrical connection from line 1 through cable 5 and contact members 3, 3a to a branch line such as the line 1a that can be supported at the top of the insulator column 2. Fig. 1a shows the contact members 3, 3a in separated position in which the cable 5 is substantially completely wound upon the drum 4.

In the embodiment illustrated in Fig. 2, the lower, fixed contact being omitted for purposes of simplification since it is identical with the arrangement shown in Fig. 1, it will be observed that the cable 5 which is wound and unwound on drum 4' has one end S'a secured to the supporting frame 9 and the other end secured to the drum 4. The weight contact 3' has an eyelet 10 secured to the same and the cable 5' passes through the eyelet. Thus as the cable 5' is wound and unwound on the drum 4 the weight contact 3' will be raised and lowered, respectively. Otherwise, the structure is identical with that shown in Fig. 1.

Figs. 3 and 3a illustrate an embodiment wherein the movable, lowerable contact member is suspended from the line cable 1 by means of a toggle lever arrangement. The movable contact member 11, preferably designed with one or more spade-like contact parts, is adapted, upon lowering to engage a trough-shaped, fixed, countercontact 19 carried at the upper end of the pedestal insulator 2. The spade-like configuration for the movable contact member 11 cooperates with the complementary configured trough-like fixed contact 19 in the same manner as the frusto-conical members 7, 8 in the embodiment of Fig. 1, namely to assure engagement between the contact members notwithstanding swinging movement of the movable contact member 11 due to movement of the line 1. Fig. 3 shows the movable contact member 11 in the lowered position in engagement with the fixed, countercontact member 19, and Fig. 3a shows the contact member 11 in the raised position. The movable contact 11 is located at the free end of the lower arm 12 of the toggle, while the other lever arm 13 of the toggle, constructed in the form of a tube, is rotatably disposed at the line cable 1. At one end of lever arm 13 revolving about a fixed axis at the line cable 1 there is a sprocket wheel 14 concentric with the axis of rotation, and a second sprocket 15 is located at the opposite end of lever arm 13 concentric with the axis of rotation of lever arm 12 so that a differential movement is produced between the two lever arms. The sprockets 14 and 15 are interconnected by a sprocket chain 16. Actuation of the toggle comprised by levers 12, 13 is effected by means of another lever 17 which is articulated to the toggle lever 13 and is caused to rotate by a suitable driving mechanism. In the closed position, where the movable contact member 11 is engaged with the fixed contact member 19, the toggle levers 12, 13 are disposed in outstretched, aligned position as is clear from Fig. 3, while in switch, the toggle levers 12, 13 are folded.

Various types of drive mechanisms may be utilized for actuating the toggle levers 12, 13. The drive 30, e. g. compressed air or an electric motor, is mounted atop a gantry 31 to which one end of the cable 1 is anchored by means of laterally extending'arm 33 of insulating material. The movements of the drive are transmitted from the drive itself through an insulating shaft 32 and an endless rope 18 to the lever mechanism 17 for actuating the toggle levers 12, 13. It is possible also to make the entire transmission from the drive to the disconnect switch mechanism only by means of a rope or an insulated shaft. Naturally the drive may also be disposed at a different point on the gantry, for example at mid-height, or even on the ground at the foot of the gantry. Then also, the drive may be mounted on a special supportinginsulator and the control movements may be transmitted to the movable contact member of the disconnecting switch by means of a rope. For manual operation of the movable contact member in the event of an emergency, a supplementary compressed air tank can be provided, the tank being disposed parallel to the supply line for the compressed air drive. The drive as described above for the embodiment of Figs. 3 and Sa'can also be applied to the embodiment shown in Figs. 1 and 1a.

Still another embodiment of the invention is illustrated in Figs. 4 and 4a. Here the movable contact member 20 in the form of a downwardly opening U-shaped member with spreading arms 20a is mounted at one end of a tubular bar 21 which is mounted for rotation approximately in the center at the line cable 1. Bar 21 which, in the disconnected position (Fig. 4a) is parallel to the line cable 1, is first caused to rotate through an angle of about 90 by means of a transmission gearing during a connection stroke and then is caused to move downward until the arms 20a of the contact member 20 embrace the fixed contact 22. Details of the movement of bar 21 are as follows: First the bar 21 is rotated through an angleof about 90 by means of a toothed segment 23 which comes into engagement with a gear wheel 24 disposed on bar 21. By such movement another gear wheel 25, on whose axis a roll of wire rope 27 is rigidly cottered, is likewise rotated through an angle of about 90 and comes into engagement with a spatially fixed gear wheel 26, owing to which the bar 21 is let down by means of the wire rope 27. The rotary movement of bar 21 and contact member 20 is indicated by the arrows in Fig. 4a. The gear transmission and the bar 21 are all carried by a support structure 28 and the gear transmission can be driven by means similar to those illustrated in connection with the embodiment of Figs. 3 and 3a. Bar 21 is, of course, electrically connected with the line 1.

The embodiments of Figs. 3, 3a and 4, 4a have the same principal advantage as that inherent in Figs. 1, la and 2, namely that the force of gravity is employed in moving the movable contact toward the fixed contact and maintaining pressure between the two after engagement therebetween.

The disconnect switch in accordance with the present invention is not limited to the specific embodiments illustrated but rather its principles are applicable to still further embodiments. For example, the movable, lowerable contact may be fastened to a scissor type of lever mechanism mounted on the line cable, the scissor being capable of various forms. However, in all embodiments the current carrying parts of the disconnect switch are preferably made of light-weight electrically conductive metallic material such as aluminum or aluminum alloy.

Many advantages flow from the invention which cannot be obtained with other types of disconnect switches wherein the movable contact is carried by the insulator pedestal and must move upward to engage the fixed contact member that is secured to the overhead line. Because the drive is separated from the switch mechanism the supporting insulator is greatly relieved and consequently its dimensions may be made smaller and the cost reduced correspondingly. Also the contact engagement is much improved because the natural weight of the movable contact acts downward, under the force of gravity, to thereby increase the pressure upon the fixed con tact on which it rests. By the manner of suspending and operating the disconnect switch, a reliable closing of the switch contacts is achieved regardless of changes in position of the overhead line due to wind presure, ice, etc. At the same time, ice formation at the contacts and in part also at the disconnect switch itself is prevented in the embodiments of Figs. 3 and 4, namely as a result of the small movements of the movable contact relative to the counter, fixed contact caused by vibrations in the line, or variations in its position. Lastly, all intermediate structures for equalizing the line vibrations or variations in its position become unnecessary.

We claim:

1. In a disconnect switch of the vertical column type for a high voltage line where the switch contacts are structurally separated from each other, the combination comprising an insulating support disposed below said line, a fixed contact carried by said support, a movable contact electrically connected to said high voltage line, and electrically conductive means for lowering said movable contact from said line into engagement with said fixed contact.

2. A disconnect switch as defined in claim 1 wherein said movable contact is constituted by a weighted member, and said means for lowering said movable contact into engagement with said fixed contact is comprised of a flexible electrically conductive cable, said weighted member being secured to one end of said cable, and a drum upon which said cable is Wound and unwound thereby to raise and lower respectively said weighted member.

3. A disconnect switch as defined in claim 1 wherein said movable contact is constituted by a weighted member, and said means for lowering said movable contact into engagement with said fixed contact is comprised of a drum, a flexible electrically conductive cable adapted to be wound on and unwound from said drum, a support for said drum, one end of said cable being secured to said support and the other end being secured to said drum, and said weighted member including an eye element through which said cable is passed.

4. In a disconnect switch of the vertical column type for a high-voltage line where the switch contacts are structurally separated from each other, the combination comprising an insulating support disposed below said high-voltage line, a fixed contact carried by said support, a movable contact electrically connected to said highvoltage line, and electrically conductive means for low- 7 ering said movable contact from said high-voltage line into engagement with said fixed contact, said means for lowering said movable contact into engagement with said fixed contact being comprised of a toggle mechanism, said toggle mechanism including a first lever having one end thereof arranged for rotation about a fixed pivot axis adjacent said line, a second lever pivotally connected at one end to the opposite end of said first lever, said movable contact being mounted on the other end of said second lever, sprockets arranged respectively at the opposite ends of said first lever concentric with the pivot axes at such ends, a chain interconnecting said sprockets, said chain and sprockets being arranged to effect pivotal movement of said second lever relative to said first lever upon pivotal movement of said first lever, and means including a third lever articulated to said first lever for effecting pivotal movement of said first lever.

5. In a disconnect switch of the vertical column type for a high-voltage line where the switch contacts are structurally separated from each other, the combination comprising an insulating support disposed below said highvoltage line, a fixed contact carried by said support, a movable-contact electrically connected to said high-voltage line, and electrically conductive means for lowering said movable contact from said high-voltage line into engagement with said fixed contact, said means for low ering said movable contact from said line into engagement with said fixed contact comprising a bar having said movable contact secured to one end thereof, said bar being mounted for rotation about an axis intermediate the bar ends from a horizontal position adjacent and substantially parallel with said line to a vertical position normal to said line and in vertical alignment with said fixed contact, and said bar then being lowerable longitudinally of itself thereby to bring said contact member into engagement with said fixed contact.

6. A disconnect switch as defined in claim 5 wherein said movable contact member has a spade-like configuration and said fixed contact has a trough-like configuration whereby to facilitate guiding of said movable contact into engagement with said fixed contact.

7. In a disconnect switch of the vertical column type for a high-voltage line where the switch contacts are structurally separated from each other, the combination comprising an insulating support disposed below said high-voltage line, a fixed contact carried by said support, a gantry to which one end of said high-voltage line is secured and terminated, a movable contact electrically connected to said high-voltage line and electrically conductive means including drive means therefor mounted on said gantry for lowering said movable contact from said high-voltage line into engagement with said fixed contact.

8. The invention as defined in claim 7 wherein said drive means for said contact lowering means is comprised of an endless drive.

9. The invention as defined in claim 7 wherein said drive means for said contact lowering means is comprised of an endless drive and an insulating shaft.

10. The invention as defined in claim 7 wherein said drive means for said contact lowering means is comprised of a compressed air motor and which further includes a supplementary compressed air tank disposed parallel to the air supply line for said drive to permit manual operation of said disconnect switch.

11. A disconnect switch as defined in claim 1 wherein said means for lowering said movable contact into engagement with said fixed contact includes drive means therefor mounted upon a support below said line, and an endless drive transmission extending from said drive means to said contact lowering means.

12. A disconnect switch as defined in claim 1 wherein said means for lowering said movable contact into engagement with said fixed contact includes drive means therefor supported on the ground below said line.

13. A disconnect switch as defined in claim 1 wherein the electrically conductive components of said switch excepting said movable and fixed contacts are made of light-weight metal.

References Cited in the file of this patent FOREIGN PATENTS 14,908 Great Britain July 4, 1903 113,617 Sweden Mar. 27, 1945 168,743 Austria July 25, 1951