AU2011203124B2

AU2011203124B2 - Device for electric connection of a conductor such as that of an electric bushing belonging to the insulating enclosure of an electric switchgear apparatus to a conductor such as a cable

Info

Publication number: AU2011203124B2
Application number: AU2011203124A
Authority: AU
Inventors: Francois Famy; Jean-Pierre Kersusan; Thierry Milan
Original assignee: Schneider Electric Industries SAS
Current assignee: Schneider Electric Industries SAS
Priority date: 2010-07-02
Filing date: 2011-06-28
Publication date: 2015-02-05
Anticipated expiration: 2031-06-28
Also published as: AU2011203124A1; FR2962262A1; EP2403086A1; FR2962262B1; BRPI1103243A2; CN102394393A

Abstract

DEVICE FOR ELECTRIC CONNECTION OF A CONDUCTOR SUCH AS THAT 5 OF AN ELECTRIC BUSHING BELONGING TO TH4 INSULATING ENCLOSURE OF AN ELECTRIC SWITCHGEAR APPARATUS TO A CONDUCTOR SUCH AS A CABLE. The present invention relates -to a device for electric connection of t e conductor called 10 first conductor (1) of an electric bushing (2) belonging to the insulating enclosure of an electric switchgear apparatus to a conductor called second conductor (G) such as a cable or fuse, said bushing comprising said second conductor at least partially surrounded by an insulating part, said device comprising a connection interface (8) Lo perform electric connection between the above-mentioned first conductor (1) and the second conductor (3), 15 and a deflector fitted around the above-mentioned connection interface (8) and electrically connected to the conductor (1) of the bushing (2). This device is characterized in that it comprises an insulating sleeve (9) comprising a main part (10) fitted ar und the connection interface (8), an end part (11), called first end part, fitted in tight manner around the insulating part of the bushing and an end part (12), called second end part, fitted in tight 20 manner around the end of the conductor called second conductor (3), said main part (10) comprising a conductive portion (14a,14b) electrically connected to sai 1 first conductor (1) on at least a part of its inner surface. <4' 2 14a -10 1kl5

Description

Pool Section 29 Regulation 3.2(2) AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATIbN STANDARD PATENT Application Number: Lodged: Invention Title: Device for electric connection of a conductor Such as that of an electric bushing belonging to the insulating enclosure f an electric switchgear apparatus to a conductor such as a cable The following statement is a full description of this invention, including the best method of performing it known to us: P111ABAU/0610 1 DEVICE FOR ELECTRIC CONNECTION OF A CONDUCTOR SUCH AS THAT OF AN ELECTRIC BUSHING BELONGING TO THE INSULATING ENCLOSURE OF AN ELECTRIC SWITCHGEAR APPARATUS TO A CONDUCTOR SUCH AS A CABLE 5 The present invention relates to a device for electric connection of an electric conductor called first conductor to an electric conductor called second conductor, said first conductor being at least partly surrounded by an insulating part, said device comprising a connection interface to perform the electric connection between the above-mentioned first 10 and second conductors, and a deflector placed around the above-mentioned connection interface and electrically connected to the conductor called first conductor. Electric connection of the conductor of a bushing belonging to the enclosure of a medium voltage switchgear apparatus to another conductor such as a cable or fuse is achieved by 15 means of a connection interface which has the particularity of presenting three different materials coinciding at one point. This particularity makes this area particularly sensitive to electric fields. The combination of these stresses with other stresses such as the presence of water, and other aggressive agents such as pollutants contained in the air, makes this area even more sensitive to electric fields. 20 Current realisations use conventional deflectors limited to the electric connection area in order to mask the square edges of the conductors. Any discussion of documents, devices, acts or knowledge in this specification is included 25 to explain the context of the invention. It should not be taken as an admission that any of the material formed part of the prior art base or the common general knowledge in the relevant art in Australia on or before the priority date of the claims herein. It would be desirable to provide a device for electric connection of two conductors 30 enabling the dielectric withstand of the compartment comprising such a device to be improved, in particular the withstand in case of lightning strike and the ageing resistance in harsh climatic environments (pollution, humidity, salt-laden fog, etc...).

2 In accordance with the present invention, there is provided a device for electric connection of a first electric conductor to a second electric conductor, said first conductor being at least partially surrounded by an insulating part, said device including a connection interface to make the electric connection between the first and second 5 conductors, and a deflector placed around the connection interface and electrically connected to the first conductor, wherein the device further includes an insulating sleeve including a main part placed around the connection interface, a first end part fitted tightly around the insulating part of the first conductor and, a second end part fitted tightly around an end of the second conductor, said deflector including a conductive portion on at 10 least part of an inner surface of the main part of the sleeve, the conductive portion being electrically connected to said first conductor, and wherein the second end part only of the sleeve, or an assembly formed by the main part and the second end part of the sleeve, are returnable around the first end part of the sleeve, and wherein first end part of the sleeve includes a gripping part designed to facilitate fitting of the sleeve. 15 A sleeve-deflector thus sleeves the connection interface encompassing the live conductors, creating a dielectric tightness in the connection areas. According to a particular feature, the end of the conductor called second conductor is covered over a certain length by an insulating termination and the second end part of the 20 above-mentioned sleeve is fitted tightly around said termination. According to another feature, the free end of the second end part is fixed by hoop-binding on said termination. According to another feature, the conductor called second conductor comprising a grounded cable shield stopping at a certain distance from the end of said conductor, the 25 second end part of the sleeve is extended so as to sleeve the termination until it partly covers the end of the cable shield. According to another feature, the above-mentioned conductive portion is achieved by means of a conductive paint placed on at least a part of the inner surface of the main part of the sleeve. 30 According to another embodiment, the above-mentioned conductive portion is achieved by means of a conductive elastomer insert overmoulded by the insulating material of the sleeve.

2a According to another feature, only the second end part of the sleeve, or the assembly formed by the main part of the sleeve and the second end part of the sleeve, forms a returnable part around the first end part of the sleeve. This makes for easy connection of the conductors. 5 According to another feature, the main part and/or the second end part of the sleeve comprises fins designed to increase the creepage distance between the live parts and the grounded parts. 10 According to another feature, the main part and/or the second end part of the sleeve comprises at least a part in the shape of an accordion so as to enable easy adjustment of the sleeve by extension of the bellows to the required overlap length of the second conductor or to the length of an insulating termination fitted around said conductor.

3 According to a particular embodiment, the sleeve is made in a single pan. According to another embodiment, the above-mentioned sleeve is ma+ up from two parts 5 comprising a first part comprising the main part and the first end part o the sleeve, and the second part comprising the second end part of the sleeve, According to another feature, the second part is fixed to the first part Iby clip-fastening or I hoop-binding means so as to enhance the tightness between these tw parts and between 10 the sleeve and cable. According to another feature, this device comprises a washer integ 1 to the conductor called first conductor, said washer electrically connecting the conductie part of the sleeve and said conductor called first conductor, and being designed to enable clip-fastening of 15 the sleeve when this sleeve is fitted on the conductor called first conductor. According to another feature, on the same side as the first conductor, te sleeve comprises a gripping part designed to facilitate fitting of the sleeve on the side where the first conductor is located. 20 According to another feature, the conductor called second cond ctor comprising a grounded cable shield stopping at a certain distance from the end of 'aid conductor, this device is characterized in that the device also comprises a deflector tixed via one of its ends to the free end of the above-mentioned second end part of the sleeve by 25 overmoulding, and presses, via its opposite end, on the sheath of the above-mentioned cable shield. According to a particular feature, the end of the conductor called Iecond conductor is covered over a certain length of an insulating termination, and the sleeve and termination 30 are formed by one and the same part.

4 According to another feature, the first conductor is that of a bushifg belonging to the insulating enclosure of an electric switchgear apparatus and the second conductor is that of a cable. 5 According to another feature, the first conductor is that of one end of a fuse and the second conductor is that of a cable or of a fuse. The invention also relates to a connection device comprising a firs connection device comprising the above-mentioned features taken either alone or in combination, wherein the 10 first conductor is that of a bushing and the second conductor is that of one end of a fuse, and a second connection device comprising the above-mentioned features taken either alone or in combination, wherein the first conductor is that of the othe. end of the fuse and the second conductor is that of a cable. 15 But other advantages and features of the invention will become more c early apparent from the following detailed description which refers to the accompanying drawings given for example purposes only and in which: -Figure 1 is a partial axial cross-sectional view illustrating the connection device according 20 to a first embodiment of the invention, -Figure 2 is a partial axial cross-sectional view illustrating the connection device according to a second and a third embodiment of the invention, respectively situated on the left-hand side and the right-hand side of the figure, 25 -Figure 3 is a partial axial cross-sectional view illustrating the connection device according to a fourth embodiment of the invention, -Figure 4 is a partial cross-sectional view illustrating the contact made by the braid with the 30 bottom deflector of the sleeve, -Figure 5 is a partial cross-sectional view illustrating fixing of the braid 5 -Figure 6 is a partial axial cross-sectional view illustrating the connection device according to a fifth embodiment of the invention, and 5 -Figure 7 is a partial axial cross-sectional view illustrating a connection device according to the invention designed to perform the electric connection at the bottom part between a fuse and a cable, and at the top part between a bushing of a switchgear appaatus and a fuse. In figure 1, a connection device D according to a first embodiment of he invention can be 10 seen designed to perform connection of a first conductor 1 housed in a ushing 2 belonging to the enclosure of an electric switchgear apparatus with a second conductor 3 in the form of an electric cable. This cable is equipped with a cable shield 4 fitted around the end p irt of the conductor called second conductor 3 but without extending right up to the end 4f the latter, thereby 15 leaving an end part 5 not covered by the shield, said shield 4 being electrically grounded. This cable is also equipped with an insulating termination 6 fitted around the end part of the cable and covering an end part 7 of the cable shield 4. The above-mentioned two conductors 1,3 are electrically and mechanically connected by means of a connection interface 8. 20 According to the invention, this interface 8 is surrounded by an elastomer sleeve 9 comprising a main part 10 fitted around the interface 8, on each side o which there extend two end parts 11,12 fitted tightly respectively around the bushing 2 and around the termination 6. This sleeve 9 comprises a deflector 14 on its inner face. This figure illustrates two possible embodiments of this deflector, i.e. a deflector 14a in the form of an 25 overmoulded elastomer insert, on the left-hand side of the figure, nd a deflector 14b constituted by a conductive paint on the right-hand side of the figure, This deflector 14 is electrically connected to the first conductor 1. It should be noted that the elastomer material forming the sleeve is a seductive elastomer material identical to or compatible with the insulating part of the sleeve in order to 30 facilitate adhesion between the two elements. According to this embodiment, the second end part 12 and also the main part 10 of the sleeve 9 are returnable around the first end part 11.

6 A split toroidal ring made from insulating material 15 is placed around the second end part 12 of the sleeve 9 so as to improve the rigidity of clamping of this sleeve on the termination thereby improving the tightness between this sleeve 9 anL the termination 6. The apparatus can be immersed as from this level. 5 This ring can be moulded from a casting or added-on. Complete tightness has therefore been achieved starting from th end of the cable termination 6 up to the enclosure. On account of the dielectric improvement of the connection, this embodiment already enables simplified short cable ends to be used (without adding additional fins), which are therefore more economical.! 10 It should also be noted that fixing of the sleeve can for example be pe formed by a part 16 screwed onto the insert 1 on which the sleeve 9 positions itself when hitting of the latter is performed. In figure 2, two different embodiments of the device of the invention h ve been represented in which the sleeve 9 is extended so as to cover the cable termination. According to the 15 embodiment illustrated in the left-hand part of the figure, the sleeve is made in a single part, whereas according to the second embodiment illustrated in the right-hand part, the sleeve 9 is formed by two different parts 9a,9b fixed to one another by hoop-binding (left hand part of the drawing) or by clip-fastening (right-hand part of the drawing). The first part 9a comprises the first end part 11 and the main part 10 whereas the second part 9b 20 forms a sock constituting a protective addition of the termination whi :h will really enable shorter terminations to be used as large creepage distance lengths do not have to be managed in harsh climatic environments. According to the embodiment illustrated in figure 2, the second end iart 12 and the main part 10 are in the form of an accordion, which makes for easy adjustrient of the sleeve to 25 the length of the termination by extension of the bellows, and an increase of the external creepage distances in the manner of insulator fins. On the right-hand slide, only the second part of the sleeve is achieved in this form, the first part of the sleeve 9 being able to be returnable. The free part of the first end part 11 is in the form of a grip 13, as is the case for figure 1. 30 Fixing of the sleeve 9 on the bushing 2 is performed by means of a large conducting washer 17 fixed to the insert 1, which also enables the inner conducting area of the sleeve acting as deflector to be at the same potential, as is also the case for fig re 1.

7 At the level of its free end, the sock thus created by the second end part 12 can be free or be bound 22 thereby creating a second tightness. According to the embodiment illustrated in figure 3, the sleeve 9 is thi time provided with 5 a deflector 18 at the bottom part thereof to improve the dielectr withstand of the termination, this deflector reducing the electric field concentrations resent at the level where the shielding stops. This deflector 18 is, in the described embod iment, overmoulded by the insulating material of the sleeve 9 at one of its ends 18a, wherea its other end 18b is put under pressure by extension on the bottom part of the termination +d on the protective 10 sheath of the cable, which enables ground potential to be achieved by homing into contact with the braid of the cable. This also prevents the occurrence of partly discharges in the case of the use of short terminations that have been incorrectly fitted, which results in enhanced dependability of the connection. 15 According to the embodiment of figure 4, the bottom part of the sleeve flattens the braid 19 thereby ensuring that its bottom deflector is at the same potential. According to the embodiment illustrated in figure 5, the deflector 18 comprises a housing 20 inside which the braid 19 can be secured by a clip 21, which represents another possible mode of ensuring that it is at the same potential. 20 According to the embodiment described in figure 6, the termination and sleeve 9 form one and the same part. In this case, tightness problems between the sleeve and termination arl eliminated and the number of parts is limited, thereby improving the dependability even further. 25 According to the illustrated in figure 7, a fuse 23 is electrically connected via one 23a of its ends to the conductor 24 of a bushing belonging to the insulating enclosure of an electric apparatus by means of a first connection device 25, and via its opposite end 23b to a second connection device 26 which is connected load-side to the cabbt 27 by means of a connection device 28 according to the invention, the sleeve 29 of whid h presents a double 30 cavity 30 in this particular exemplary embodiment. It should be noted that at the level of the first connection device, electric contact is ensured by contact grips enabling plug-in to be performed in the horizontal plane, whereas at the 8 level of the second connection device, electric contact is this time p rformed by contact grips called "tulip-finger" contact grips enabling plug-in to be performed in the vertical plane. Fitting of the connection device according to the invention can be p rformed for all the 5 described exemplary embodiments in the two following manners. The parts 16 and/or 17 are fixed beforehand on the conductive insert I of the bushing 2. According to the first manner: First of all, the sleeve 9 is fitted around the cable 3. Then the condu tive insert 1 of the bushing 2 is fitted inside the sleeve 9. Electric connection of the conductors is then 10 performed. Then the sleeve is fitted (by engagement, upward translation) and &lip-fastened in the housings formed by the insulating parts and the parts 16 and/or 17 fixdd on the conductive insert I of the bushing 2. The sleeve 9 is then positioned on the bushing 2 by exerting a traction on the grip 13 so as 15 clip-fasten the sleeve 9 on the washer 16,17. According to the second manner of making the connection: First of all, the sleeve 9 is fitted before electric connection of the cond ctors is performed. The second end part 12 of the sleeve and the main part 10 of said sleeve are then either turned or compressed, depending on the case, so that electric connect n of the conductors 20 can be made. This second part 12 is then decompressed or turned so as to envelop thl interface 8 and the end of the termination 6. When the sleeve 9 is in two parts 9a,9b as illustrated in figure 2, the s cond part 9b is first of all fitted on the cable. Then, after the first part 9a has been fitted arc und the interface 8, 25 fitting of the part 9a is performed as described in the foregoing. Then the two parts of the sleeve are secured to one another by clip-fastening or hoop-binding. Fitting of the device according to the embodiments of figures 3 to 5 i the same as that of figure 2 and will therefore not be described again Concerning figure 6, the assembly formed by the termination and sleeve is previously fitted 30 on the cable in identical manner to a conventional termination. Electr c connection of the conductors is then performed, freeing the necessary space, either by tu ning the sleeve part 9 downwards this time, or in the case of compressible shapes (a cordion-shape) by downward compression of this zone. It should be noted that the elastomer material from which the sleeve of the invention is made enables a large variation of diameter to be accepted while at the same time 5 guaranteeing the termination-sleeve contact ensuring tightness. In case of the necessity of managing a wide range of cable diameters or of fuse diameters, several sleeve sizes can be provided for the part 12, or for the smallest sizes, a simplified cylindrical sleeve can be fitted forming a spacer. Thus, in all these exemplary embodiments, distribution of the electric field is ensured by a 10 conductive shield 14a overmoulded by an elastomer material able o be used in high voltage, preferably EPDM or Silicone, or a conductive paint 14b at the potential of the high voltage. The connections at the level of the cable and of the enclosure are rendered tight due to the deformable silicone sleeve. Deformation of the sleeve takes place on assembly of the device, this deformation enabling clamping forces guaranteeing good tightnesses to 15 be achieved, By improving the dielectric tightness, these sleevings ena le the cable ends to be simplified and made more dependable in particular in harsh nvironments. This tightness is such as to allow the switchgear apparatus to be immersed uj to this connection area. 20 The invention can be advantageously applied to any device for conn acting a cable on a bushing. The invention is naturally in no way limited to the embodiments descl bed and illustrated which have been given for example purposes only. 25 On the contrary, the invention extends to encompass all the technical equivalents of the described means as well as combinations thereof if the latter are performed according to the spirit of the invention.

Claims

1. A device for electric connection of a first electric conductor to a second electric conductor, said first conductor being at least partially surrounded by an insulating part, said device including a connection interface to make the electric connection between the first and second conductors, and a deflector placed around the connection interface and electrically connected to the first conductor, wherein the device further includes an insulating sleeve including a main part placed around the connection interface, a first end part fitted tightly around the insulating part of the first conductor and, a second end part fitted tightly around an end of the second conductor, said deflector including a conductive portion on at least part of an inner surface of the main part of the sleeve, the conductive portion being electrically connected to said first conductor, and wherein the second end part only of the sleeve, or an assembly formed by the main part and the second end part of the sleeve, are returnable around the first end part of the sleeve, and wherein the first end part of the sleeve includes a gripping part designed to facilitate fitting of the sleeve.

2. The device for electric connection according to claim 1, wherein the end of the second conductor is covered over a certain length by an insulating termination and wherein the second end part of the sleeve is fitted tightly around said termination.

3. The device for electric connection according to claim 2, wherein the free end of the second end part is fixed by hoop-binding on said termination.

4. The device for electric connection according to either claim 2 or 3, wherein the second conductor includes an earthed cable shield stopping at a certain distance from the end of said second conductor, the second end part of the sleeve is extended so as to sleeve the termination until it partly covers the end of the cable shield.

5. The device for electric connection according to any one of the foregoing claims, wherein the conductive portion is provided by a conductive paint placed on at least a part of the inner surface of the main part of the sleeve. 11

6. The device for electric connection according to any one of claims 1 to 4, wherein the conductive portion is provided by a conductive elastomer insert overmoulded by the insulating material of the sleeve.

7. The device for electric connection according to any one of the foregoing claims, wherein the main part and/or the second end part of the sleeve includes fins designed to increase the creepage distance between live parts and grounded parts.

8. The device for electric connection according to any one of the foregoing claims, wherein the main part and /or the second end part of the sleeve includes at least one part in the form of an accordion so as to enable easy adjustment of the sleeve by extension of the bellows to the required overlap length of the second conductor or to the length of an insulating termination fitted around said conductor.

9. The device for electric connection according to any one of the foregoing claims, wherein the sleeve is made in a single part.

10. The device for electric connection according to any one claims 1 to 8, wherein the sleeve is made in two parts wherein a first part includes the main part and the first end part of the sleeve, and a second part includes the second end part of the sleeve.

11. The device for electric connection according to claim 10, wherein the second part is secured to the first part by clip-fastening or hoop-binding means so as to enhance the tightness between these two parts and between the sleeve and cable.

12. The device for electric connection according to any one of the foregoing claims, further including a washer integral to the first conductor said washer electrically connecting the conductive part of the sleeve and said first conductor, and being designed to enable clip-fastening of the sleeve when the sleeve is fitted on the first conductor 12

13. The device for electric connection according to any one of the foregoing claims, wherein the second conductor includes an earthed cable shield stopping at a certain distance from the end of said second conductor, and wherein another deflector is fixed via one of its ends to the second end part of the sleeve by overmoulding, and presses via its opposite end on the sleeve of the cable shield.

14. The device for electric connection according to claim 1, wherein the end of the second conductor is covered over a certain length by an insulating termination and wherein the sleeve and termination are formed by one and the same part.

15. The device for electric connection according to any one of the foregoing claims, wherein the first conductor is that of a bushing belonging to the insulating enclosure of an electric switchgear apparatus and the second conductor is that of a cable.

16. The device for electric connection according to any one of claims 1 to 14, wherein the first conductor is that of one end of a fuse and the second conductor is that of a cable or of a fuse.

17. A device for electric connection, including a first connection device according to any one of claims 1 to 15, wherein the first conductor is that of a bushing and the second conductor is that of one end of a fuse, and a second connection device according to any one of claims 1 to 15, wherein the first conductor is that of the other end of the fuse and the second conductor is that of a cable.

18. A device for electric connection, substantially as herein before described with reference to any one of the embodiments illustrated in the accompanying drawings. SCHNEIDER ELECTRIC INDUSTRIES SAS WATERMARK PATENT AND TRADE MARKS ATTORNEYS P34682AU00