Flexible medium voltage interconnection and method to obtain same

ES 2 269 321 T3

DESCRIPTION

Flexible medium voltage interconnection and method of obtaining it.

The present invention relates to a method of providing a medium voltage interconnect for making an electrical connection between a receive connector of a first equipment station and a receive connector of a second x.

Such interconnection is generally known in the art. It is made with a metallic conductor at the ends of which electrical connectors are mounted. The electrical connector mates with the receiving connector which is generally part of a "terminal" of an equipment station. The equipment station is typically a transformer or switchgear in a transformer station, and the properties of the connectors are therefore preferably standardized.

The electrical connector is molded from polyethylene material so as to form a solid conductive core enclosed within a shielded insulating body. As a result, the interconnect is relatively rigid and furthermore it is not available in different relatively short lengths, for example about 30 cm.

A connector of this kind has been described in document ECR-2 741 484. This document refers to an electrical connector for connecting, for example, two cables, and comprises a conductive core that includes a metallic conductor that carries at each end an electrical connector. It also includes an elastic protective sleeve, made of a layer of semiconductor or conductive rubber. This connector is prefabricated by molding a single piece element.

It is also known, from document EP-0 406 509, an interconnection adapted to electrically connect a first equipment to a second equipment, said interconnection comprising a conductive core that includes a conductor made, preferably, of conductive silicone rubber with, at each end thereof, an electrical terminal adapted to be coupled with the corresponding parts of the equipment to be connected, and a flexible sheath having at least one insulating layer made of an elastomeric material, synthetic resin such as synthetic rubber or silicone, said flexible sheet covering the entire conductive core. The method of manufacturing the interconnect in this document is a molding method, such that the element and the sleeve are one piece.

An object of the present invention is to provide an interconnect of the known type described above, but whose electrical connectors are relatively more flexible, and are available in different lengths at no significant extra cost.

According to the invention, this object is achieved by the method of claim 1.

In this way, the molding process is replaced by an extrusion process. As a result, the conductive core is composed of a flexible conductor connected to two electrical connectors, fully encased within an elastic sleeve or tube to define isolated connection interfaces for mating equipment receiving connectors. For many applications, flexible interconnects are more suitable, due to the flexibility of the material and its dimensions.

The method of the present invention preferably comprises the steps of providing said substantially cone-shaped electrical connector whose base has a diameter relatively larger than the diameter of said metallic conductor, and connecting said base to one end of said metallic conductor.

The interconnection thus obtained is better adapted to normal bushings.

More particularly, the present method further comprises the step of applying one end of said flexible tube inside an inner side of a conical terminal means, made of insulating material and provided with said receiving connector so as to lead to the electrical connector of the conductive core in contact with said receiving connector, and said insulating layer of said flexible tube in contact with said inner side of said terminal means.

In a preferred embodiment, said method comprises the steps of providing said flexible tube with, starting coaxially from the center:

- a first semiconductor layer,

- an insulating layer made of elastomeric material, and

- a second semiconductor layer.

Such an extruded three-layer tube gives the best results with regard to flexibility and insulation properties.

Also, in a preferred embodiment, said method further comprises the steps of:

- providing an external locking ring on at least one electrical connector of said conductive core, and

- Arranging within said flexible tube at least one groove for an internal ring, to receive the locking ring of said electrical connectors when the tube is released on said conductive core.

The hose or hose is then locked onto the electrical connectors or end pieces of the conductive core, to prevent any relative movement. The splines can also be used to retain sliding outer clamps, to mechanically clamp each electrical connector, and possibly to continuously achieve external shielding between the interconnect and the mating parts.

The present invention also relates to a medium voltage interconnect obtained by the method of the invention and adapted to electrically connect a receive connector of a first equipment station with a receive connector of a second equipment station.

The medium voltage interconnection is characterized in that it comprises a conductive core that includes a metallic conductor with, at each end thereof, an electrical connector adapted to mate with said receiving connector, and a flexible tube that has at least one insulating layer made of elastomeric material that covers the entire conductive core.

In a characterizing embodiment of the present invention, said elastomeric material is a synthetic terpolymer of ethylene, propylene and diene (EPDM).

In a variant, said elastomeric material is a silicone.

ES 2 269 321 T3

These materials are preferred for their good flexibility and insulation qualities.

Other characterizing embodiments of the present method and medium voltage interconnection are mentioned in the dependent claims.

It should be noted that the expression "comprising", used in the claims, should not be construed as limited to the means listed below. Consequently, the scope of the expression "a device comprising means A and B" should not be limited to devices consisting only of components A and B. It means, with respect to the present invention, that the only relevant components of the device are A and B.

Similarly, it is to be noted that the term "coupled", also used in the claims, should not be construed as limited to only direct connections. Consequently, the scope of the expression "a device A coupled to a device B" should not be understood as limited to devices or systems in which an output of device A is connected directly to an input of device B. It means that there is a path between an output of A and an input of B, which can be a patch that includes other devices or media.

The foregoing and other objects and features of the invention will become more apparent, and the invention itself will be better understood, if reference is made to the following description of an embodiment, taken in conjunction with the accompanying drawings, in which:

Fig. 1 represents a longitudinal view of a conductive core 1 of a medium voltage interconnect according to the invention.

Figs. 2a and 2b represent a left end view and a sectional view of a flexible tube 5 used in the interconnection of the invention;

Fig. 3 represents the left end of the flexible tube 5 of Fig. 2 prepared to receive the conductive core 1 of Fig. 1;

Fig. 4 represents the left end of the complete assembly of the medium voltage interconnect of the invention, which includes the conductive core 1 of Fig. 1 and the flexible tube 6 of Fig. 3; Y

Fig. 5 represents the left end of the medium voltage interconnect applied to a terminal of an equipment station.

It should be noted that all views, except that of Fig. 2b, are cross-sectional views along the longitudinal axis, and that although only the left end of the medium voltage interconnect has been shown in Fig. 2a , 3, 4 and 5, the right end of that interconnection is identical to this one. Furthermore, the different views have not all been represented to the same scale.

The flexible interconnect of the present invention is intended to be used to electrically connect medium voltage electrical devices located at different equipment stations. One such electrical device is, for example, a switchgear of a transformer operating at voltages above 1 kV and enclosed in an equipment station that is a tank or a cubic vessel. The equipment station is filled with an isolated medium which is a gas or petroleum fluid, generally sulfur hexafluoride (SF6) under pressure. Each terminal of the electrical device is connected to a so-called "bushing well" or "bushing", hermetically mounted within a hole in a wall of the equipment station.

The bushing well is an insulating molded hollow cone provided with a metal rod that interconnects a connector on the top of the outer side of the cone with a receiving connector on the inner side of that cone, inside the well. The receiving connector meets the requirements of ANSVIEEE Standard 3861977, as is the case for the well-known terminal well called “Clamping Apparatus Terminal Well with Joint K16O1PCC / K1601PCCR”, from AMERACE ™ Ltd (10 Esna Park Drive Markham, Ontario, Canada, L3R 1E1 / 1 November 1983). It is to be noted that bushing wells of other dimensions can also be used, but which remain coupling to the present interconnection.

One side of the terminal, generally the outer side of the cone, is immersed in the insulated medium of the equipment station and electrically connected to the electrical device, while the inner side of the cone is in ambient air and provided with the receiving connector. designed to receive one end of the flexible interconnect.

In order to interconnect two terminals, the flexible interconnection comprises a conductive core surrounded by a flexible tube which will be explained in detail below.

The conductive core, indicated generally by 1 in Fig. 1, is made of a flexible metal conductor 2 provided at each end with an electrical connector, indicated by arrows 3 and 4. Each connector 3/4 is adapted for mating with the terminal receiving connector.

Electrical connector 3/4 has a central 5/8 knockout hole for connection with a respective receiving connector of the terminal, and is cone-shaped, of which the 7/8 base is connected, respectively, to one end of the flexible conductor 2. This 7/8 base has a diameter that is greater than the diameter of the metallic conductor 2. The electrical connector 3/4 is further provided with an external locking ring 9/10 that engages in a groove for the inner ring of the tube. flexible.

The conductive core 1 is covered, protected and insulated by a flexible tube, generally indicated by 11 in Figs. 2a, 2b and 3, and preferably made of up to three layers of material.

The flexible tube 11 is a molded or extruded tube of a first semiconductor layer 12 (inside), an insulating layer 13 made of elastomeric material, and a second semiconductor layer 14 (outside). In order to improve the elasticity of the hose 11, the elastomeric material of the insulating layer 13 is preferably an ethylene propylene diene terpolymer (EPDM). Furthermore, this EPDM can be recycled, and is therefore environmentally friendly. The tube 11 is preferably the same length as the conductive core 1.

The flexible tube 11 is further prepared to receive the conductive core 1, as illustrated in Fig. 3. Therefore, each end of the second semiconductor layer 14 is withdrawn some distance up from the insulation material 13. At the same time, an inner ring groove 15 is provided at each end in the first semiconductor layer 12, and partially in the insulating layer 13 of the flexible tube 11. The flexible tube 11 is further expanded.

ES 2 269 321 T3 radially, and the conductive core 1 slides therein.

The flexible tube is then released onto the conductive core 1, in order to obtain a medium voltage interconnection as illustrated in Fig. 4. The flexible tube 11 has now assumed the shape of the conductive core 1 below, and this The latter is prevented from moving therein, due to the external coupling locking ring 9/10 of the conductive core, and the inner ring groove 15 of the tube. The first semiconductor layer 12 of the tube is in contact with the flexible metallic conductor 2 and the connectors 3/4.

As illustrated in Fig. 5, each end of the interface thus obtained can be fitted within an inner side 18 of a conical terminal, indicated generally by an arrow 17, as described above, and mounted in a hole in a wall 18. The receiving connector 19 of the terminal 17 is thus brought into contact with the electrical connector 3 of the conductive core through its hole 5, while the insulating layer 13 of the interconnection is brought into contact with the inner side 16 of the terminal. . In order to impart the necessary pressure on the expanded tube, to ensure tight fit contact between the mating parts of the terminal and the interconnection, a locking ring, indicated by arrow 20, is provided on the core. conductor, at each end of it. On the left side of the interconnection, the fixing ring 20 abuts against the base 7 of the conical electrical connector 3 covered by the flexible tube, and is mechanically fixed (not shown) to the terminal 17.

As an option, a flexible metal shield (not shown) can be mounted on the outside of the tube, to absorb short-circuit currents.

Finally, it should be noted that the insulating layer of the terminal device can also be made of a molded elastomeric material, preferably of an ethylene, propylene and diene terpolymer (EPDM), as for the insulating layer 13 of the flexible tube 11.

Although the principles of the invention have been described above in relation to a specific apparatus, it should be clearly understood that such description has been made by way of example only, and not limiting the scope of the invention, as it stands. defined in the accompanying claims.