AU728925B2

AU728925B2 - Connecting device for electrical connection between two gas-isolated high-voltage cubicles

Info

Publication number: AU728925B2
Application number: AU75091/98A
Authority: AU
Inventors: Gabriel Balsarin; Joseph Marzocca; Nicolas Puget
Original assignee: Schneider Electric SE; Schneider Electric Industries SAS
Current assignee: Schneider Electric SE
Priority date: 1997-07-10
Filing date: 1998-07-09
Publication date: 2001-01-18
Anticipated expiration: 2018-07-09
Also published as: FR2766019A1; EP0891013B1; NO983041D0; AU7509198A; DE69834155D1; FR2766019B1; ID20985A; CN1209670A; RU2206161C2; NO314327B1; DE69834155T2; CN1159821C; ES2259200T3; EP0891013A1; NO983041L

Description

I/UU/U11 28/5/91 Regulation 3.2(2)

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: CONNECTING DEVICE FOR ELECTRICAL CONNECTION BETWEEN TWO GAS-ISOLATED HIGH-VOLTAGE CUBICLES The following statement is a full description of this invention, including the best method of performing it known to us

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CONNECTING DEVICE FOR ELECTRICAL CONNECTION BETWEEN TWO GAS- ISOLATED HIGH-VOLTAGE

CUBICLES

The invention relates to a connecting device for electrical connection between two cubicles containing high-voltage electrical switchgear housed in two tight metallic enclosures filled with insulating gas, notably sulphur hexafluoride, and including: a connecting contact cooperating at its opposite ends with a pair of inserts made of conducting material, over-cast in insulating bushings fixed in leaktight manner in two adjacent openings arranged in the metallic partitions of the two enclosures, an insulating sleeve made of flexible elastomer material coaxially surrounding the connecting contact and the connecting inserts and having two frustum-shaped terminal parts bearing on the internal surface of conjugate shape of the bushings, and means for strengthening the insulating sleeve at the level of the connection zone of the connecting contact with the inserts to prevent internal electrical flashovers.

A known device of the kind mentioned is described in the documents FR-A- 1,362,997, EP-A-199,249, EP-A-199,208 and EP-A-520,933. The connecting contact is formed either by an elongate tubular element in connection with the connecting inserts or by a set of male and female contacts arranged in the middle zone. The sleeve made of flexible elastomer can be strengthened by a conducting metallic tube extending coaxially around the connecting contact. A known assembly of this kind is well suited for two cubicles having well aligned connecting inserts, which necessitates S: very small manufacturing tolerances. In case of poor axial alignment of the inserts and bushings, the electrical connection is subjected to mechanical stresses with risks of premature wear of the connecting device.

The object of the invention is to achieve a reliable connecting device between two :l high-voltage cubicles with high dielectric resistance.

*The connecting device according to the invention is characterized in that the connecting contact is composed of a rigid central stud made of conducting material having an axial length corresponding appreciably to the separation distance between the two cubicles, and two draw-in tulip fingers articulated on the opposite ends of the

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2 central stud and extending over the whole distance of the frustum-shaped terminal parts of the sleeve and of the strengthening means.

According to a particular embodiment, the strengthening means comprise an internal core on which the insulating sleeve made of flexible elastomer material is over-cast, the material of the core being conducting and having a greater hardness than that of the material of the sleeve. The thickness of the core is smaller in the central part surrounding the stud of the connecting contact to preserve the flexibility of the sleeve in case of an axial alignment fault of the inserts.

~According to a preferred alternative embodiment, the strengthening means are formed by fitting without radial clearance of the cylindrical draw-in tulip fingers in the internal surface of the sleeve, which is covered with a coat of conducting paint to achieve uniform distribution of the electrical field. The two draw-in tulip fingers are articulated on ball joints arranged at the ends of the central stud of the connecting contact.

Other advantages and features will become more clearly apparent from the following "**description of three embodiments given as non-restrictive examples only and represented in the accompanying drawings in which Figure 1 is a schematic cross-sectional view of a connecting device according to the invention, Figure 2 shows an identical view to figure 1 of an alternative embodiment, Figure 3 represents another alternative embodiment.

With reference to figure 1, a connecting device 10 with full insulation and directed field is arranged between two high-voltage switchgear cubicles. The active part of each cubicle is housed in a sealed metallic enclosure containing an insulating gas, notably air or sulphur hexafluoride SF6. Connection is made on the side of the enclosures through two metallic partitions 12, 14 and must be leaktight to prevent gas leakages.

The connecting device 10 comprises a movable connecting contact 16 sub-divided into three parts and comprising a conducting and rigid central stud 18 supporting two 3 draw-in tulip fingers 20, 22 at its opposite ends. The movable contact 16 is arranged in a sleeve 24 made of flexible elastomer material which is fitted in hollow bushings 26, 28 made of epoxide resin, of the single-pole or three-pole type. The sleeve 24 made of elastomer material is provided with two frustum-shaped terminal parts coming into contact with the bushings 26, 28, and an intermediate connecting part of reduced cross-section.

The bushings 26, 28 are fixed onto the partitions 12, 14 of the corresponding enclosures either by several screws or by a nut 30. The tightness at the level of each enclosure is achieved by an O-ring 32 pressed onto the enclosure. A conducting insert 34, 36 is over-cast in each bushing 26, 28 and provides the connection between the movable contact 16 and the busbar of the adjacent cubicles, the rated current flowing through this insert. Each insert 34, 36 is provided with a contact with a bevelled input for ease of plug-in, even if the alignment of the two cubicles is not perfect.

The bushings 26, 28 can comprise metallic shields coated in resin to improve the distribution of the electrical field when the current is flowing.

To prevent electrical flashovers at the level of the connecting device 10, the frustumshaped parts of the sleeve 24 are compressed by the bushings 26, 28 at the level of the interface 38. For this purpose the sleeve 24 has to be reinforced by strengthening means acting on the internal diameter and on the length entering the bushings 26, 28.

In the example of figure 1, the mechanical strength is obtained by over-casting the sleeve 24 of flexible elastomer material on a core 40 made of harder elastomer material. The core 40 has a smaller thickness in the centre to preserve the flexibility of the whole assembly.

The elastomer material of the sleeve 24 is insulating whereas that of the core 40 is conducting. The conducting stud 18 of the connecting contact 16 is set to the potential of the core 40 by means of an annular protuberance 42 coming into contact with the cylindrical lateral surface of the central stud 18.

The length of this central part 18 corresponds appreciably to the length of the intermediate connecting part of the sleeve 24.

A grounded semi-conducting layer 44 is deposited or over-cast on the outside of the intermediate part of the sleeve 24 so as to form a directed field assembly insensitive to external pollution.

The two draw-in tulip fingers 20, 22 of the movable contact 16 are articulated on the ends of the stud 18 so as to be able to move in case the two cubicles are in poor alignment.

With reference to figure 2, the strengthening means of the sleeve 24 are formed by o the cylindrical-shaped draw-in tulip fingers 20, 22 fitted without radial clearance in the internal diameter of the sleeve 24 to secure the latter. The two draw-in tulip fingers 22 are advantageously mounted on ball joints 46, 48 provided at the opposite ends of the conducting stud 18 of the movable contact 16.

The internal surface of the sleeve 24 according to the example of figure 2 is covered with a coat of conducting paint 50 to achieve uniform distribution of the electrical field *00* when the current flows in the movable connecting contact 16.

•In the two embodiments of figures 1 and 2, the rigid central part 18 of the connecting 0000 contact 16 extends appreciably over a length corresponding to the separation distance between the two cubicles.

According to figure 3, the sleeve is rigidified by means of a tube 54, 56 made of insulating or conducting material and connected to the phase potential, which tube is over-cast or bonded in the elastomer material on each side of the sleeve 24.

Claims

1. A connecting device for electrical connection between two cubicles containing high-voltage electrical switchgear housed in two tight metallic enclosures filled with insulating gas, notably sulphur hexafluoride, and including: a connecting contact cooperating at its opposite ends with a pair of inserts made of conducting material, over-cast in insluating bushings fixed in leaktight manner in two adjacent openings arranged in the metallic partitions of the two enclosures, an insluating sleeve made of flexible elastomer material coaxially surrounding the connecting contact and the connecting inserts and having two frustum-shaped terminal parts bearing on the internal surface of conjugate shape of the bushings. and means for strengthening the insulating sleeve at the level of the connection zone of the connecting contact with the inserts to prevent internal electrical flashovers, characterized in that the connecting contact is composed of a rigid central stud made of conducting material having an axial length corresponding appreciably to the separation distance between the two cubicles, and two draw-in tulip fingers articulated on the opposite ends of the central stud and extending over the whole distance of the frustum-shaped terminal parts of the sleeve and of the strengthening means.

2. The connecting device according to claim 1, characterized in that the Scstrengthening means includes an internal core on which the insulating sleeve made of flexible elastomer materials over-cast, the material of the core being coo. conducting and having a greater hardness than that of the material of the sleeve. *C

3. The connecting device according to claim 2, characterized in that the thickness of the core is smaller in the central part surrounding the stud of the *.*.*connecting contact to preserve the flexibility of the sleeve in case of an axial alignment fault of the inserts.

4. The connecting device according to claim 1, characterized in that the strengthening means are formed by fitting without radial clearance of the cylindrical draw-in tulip fingers in the internal surface of the sleeve, which is covered with a coat of conducting paint to achieve uniform distribution of the electrical field.

The connecting device according to claim 1, characterized in that the two draw-in tulip fingers are articulated on ball joints arranged at the ends of the central stud of the connecting contact.

6. The connecting device according to claim 1, characterized in that the strengthening means includes a tube made of insulating or conducting material, which is over-cast or bonded in the elastomer material on each side of the sleeve.

7. A device as claimed in claim 1 substantially as herein described with reference to the accompanying drawings. DATED this 24th day of October, 2000 SCHNEIDER ELECTRIC S.A. WATERMARK PATENT TRADEMARK ATTORNEYS 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 .AUSTRALIA RCS/MBP/TJ *o* *o* *o ooooo* S S o SSSS o.S