EP3526868A1

EP3526868A1 - Underwater electrical connection system

Info

Publication number: EP3526868A1
Application number: EP17794374.3A
Authority: EP
Inventors: Aymeric ANDRE
Original assignee: SuperGrid Institute SAS
Current assignee: SuperGrid Institute SAS
Priority date: 2016-10-14
Filing date: 2017-10-11
Publication date: 2019-08-21
Also published as: US10756529B2; US20190296538A1; FR3057717A1; WO2018069651A1; FR3057717B1

Abstract

The invention relates to an underwater system for connecting at least three underwater high-voltage or very high voltage electrical cables (10', 10", 10"'), of the type comprising: - an outer cage (22) defining a connection space; - a connection fitting (30) comprising a conductive connection electrode (32) which has a junction node (34) from which at least three branches (36', 36", 36''') extend; characterised in that - each of said at least three branches (36', 36", 36''') of the conductive electrode (32) comprises a male terminal portion (38) which is connected to one of the electrical cables in a connection zone around which is mounted a connection sleeve (44, 46) made of insulating premoulded material, which receives, via each end, a male terminal portion (38) of one of the branches of the conductive electrode and the connection end of one of the electrical cables.

Description

UNDERWATER ELECTRICAL CONNECTION SYSTEM

The invention relates to a submarine connection system for sealingly connecting together at least three subsea electrical cables capable of carrying electric currents at high voltage or very high voltage, in particular continuous.

The transport of electrical energy using submarine cables, especially when carried out under high voltage or very high DC voltage, makes it possible to transport high intensity electric currents in the marine environment over long distances. therefore very important electric powers. In an electrical transmission network comprising submarine parts, it is often necessary to be able to interconnect a third offshore component to a link between two points, which may already be existing. For example, one may want to ensure the connection of an offshore wind farm to an electrical network comprising a submarine cable.

However, ensuring such a connection in the marine environment requires taking into account strong constraints. The underwater connection system must be able to withstand the hydrostatic pressure at the sea floor without damaging the cable or allowing water to seep into the electrical insulation system. The system must be able to withstand significant mechanical stresses during installation while being lightweight and compact. The connection must be installable quickly and must have sufficient reliability for operation over a very long life, which may for example be at least 30 years.

The invention finds a particularly relevant application when the submarine cables to be connected together are of the type comprising an extruded insulation.

It is illustrated in FIG. 1 an example of a submarine cable 10 with extruded insulation suitable for use in a system according to the invention. The cable 10 comprises a main conductor 12, generally filamentary, coaxially surrounded by at least one main insulating sheath 14, itself surrounded coaxially by a sealed screen sheath 16, conductor of electricity, itself surrounded coaxially by armor, for example metal armor 18. The main conductor 12 is the one which, in use, conducts the operating current under the operating voltage.

The conductor 12 is made of strong conductive material, for example metal, especially copper or aluminum or an alloy based on copper or aluminum. It can be massive, that is to say in one piece through a section, segmented into several segments through a section, in the form of strands twisted or not, etc. .... The cable 10 is in the example a unipolar cable, thus comprising in this sense a single main conductor. The cable 10 is designed to propagate a single electric potential.

The main insulating sheath 14 is made by extrusion of insulating polymer material, for example based on crosslinked polyethylene (XLPE). This insulating main sheath 14 may optionally be multilayer, with in particular several different insulating materials, for example materials having different levels of electrical resistivity.

The sealed screen sheath 16 is generally electrically conductive. It is often made of metal, for example lead or lead alloy, so usually made of strong conductive material. It protects the main insulating sheath 14 and the conductor 12 of the water. Its conductive nature also allows it to render isotropic the electric field generated by the potential of the conductor 12 of the cable 10. The sealed screen sheath 16 can also be made by extrusion.

One of the functions of the armor 18 is to give the cable 10 a mechanical strength, especially to traction, especially in view of the constraints experienced during installation. It also protects the inner layers that surround the mechanical aggression that the cable can undergo before, during and after installation. The armor 18 is generally made in particular of metal, for example copper, stainless steel or steel. The armor 18 thus generally comprises one or more layers of metal strands, for example of round or prismatic section, generally arranged helically around the axis of the cable 10.

Beyond these main components, the cable 10 generally comprises other components, in particular other layers arranged coaxially with those described above. Thus, between the conductor 12 and the main insulating sheath 14, an internal shielding layer 13 may be provided, which will preferably be a weak conductor, for example made of a polymer material loaded with conductive particles. Between the main insulating sheath 14 and the sealed screen sheath 16, an outer shielding layer 15 may be provided, which will preferably be a weak conductor, for example made of a polymer material loaded with conductive particles. Between the sealed screen sheath 16 and the armor 18, there can be provided a protective layer 17, which can be strong conductor, weak conductive, or insulating. It may for example be made of insulating polymer material, or on the contrary a polymer material loaded with conductive particles so as to form a weak conductor. Furthermore, it is generally expected that the armor 18 is surrounded coaxially by an outer protective sheath 19, for example made of polymer material.

In general, each of the components mentioned above can be of the multilayer type and / or of the multi-material type.

In this text, a material or element is considered to be:

- strong conductor if it has a resistivity of less than 10 ^"6 Ohm.m;

- weak conductor if it has a resistivity between 10 ^"6 and 10 ² Ohm.m;

- insulation if it has a resistivity greater than 10 ¹⁴ Ohm. m.

A material or element is considered conductive if it is a strong conductor or a weak conductor.

One solution for connecting together two high voltage electrical cables with extruded insulation is to use a pre-molded junction as described in US Patent No. 8,097,807-B2. This type of junction generally comprises a connection sleeve comprising a sleeve external tubular material of insulating elastomeric material, for example ethylene-propylene copolymer (EPDM) or equivalent, which is pre-molded so as to have a bore opening at its two opposite axial ends. In the mounted position of the pre-molded junction, the outer tubular sleeve can thus receive, by each end of the bore, the two connecting ends of the two cables to be connected together. At the time of assembly, the sleeve is pre-positioned on one of the two cables to be connected together, thus being offset on one side with respect to its future mounted position. The two cables will have been previously defeated, at the connection end, their metal screens and the outer layers. The conductors of the two cables, exposed at a connection area, are electrically connected. The outer tubular sleeve of the pre-molded junction is then slid along the cable from its pre-positioning position to a mounted position in which it covers the connection area of the conductors. This solution is fast to implement and reliable since the pre-molded junctions can be tested at the factory, in particular for their electrical insulation properties.

One solution for connecting together two extruded insulation high voltage submarine electrical cables by means of a pre-molded junction is to encapsulate such a junction in a two-part metal cage as described in U.S. Patent No. 8,507,795. . To do this, the armor is mechanically linked to each end of said cage by means of a steel collar welded to each strand of the armor. Curvature limiters are connected to the ends of the cage to limit the radius of curvature of the cable and thus protect the cable from excessive deformation.

Patent document GB-781.129 describes a solution for connecting together three high-voltage electrical cables using:

an external cage which delimits a connection space, the cage comprising three cable entry inlets, each provided for allow the passage of one of the cables to be connected together electrically;

a connection connection, received in the connection space and comprising a conductive connection electrode which has a junction node from which three branches extend, each branch of which is intended to be electrically connected to the connection end; one of the electric cables to be connected together electrically.

The connection fitting is embedded in an insulating layer formed of an epoxy resin block. The resin block can be applied by vacuum molding, by simple molding or by injection. The metal screen is reconstituted by means of a winding of copper ribbon. The connection of each of the three cables to the corresponding branch of the connection electrode is performed by welding or crimping. For this, each branch has a female end portion in which the connecting end of the conductor is inserted. Insulation at these connections is provided by manually winding a ribbon. However, the execution time of a wrapped junction is high, with a random realization. This system does not aim at an underwater application, the mechanical constraints related to an installation at sea are not taken into account either.

Another solution for connecting together three high voltage electrical cables is described in patent document CN-2013.03244 (Y), implementing a connection fitting composed of a central metal electrode embedded in an insulating layer in the form of a block of epoxy resin. A conductive housing that embraces and surrounds the resin block acts as a metal screen. Everything is embedded in a rigid outer cage. The metal electrode has three female cavities for connecting the connection ends of the cables. This solution concerns a terrestrial application and is not even suitable for soils saturated with rainwater. The patent document CN201797290 (U) describes an improvement of this system where the assembly is encapsulated in a steel enclosure whose sealing between the cable and the external enclosure is ensured by means of cable glands. This solution is not usable for an underwater system because the sealing system is not adapted to the hydrostatic pressure prevailing on the sea floor. The external enclosure is also not dimensioned to take into account the mechanical constraints during installation. Finally, this solution is long and complex to implement given the large number of elements to assemble.

Other cable connection systems are described in EP-2.237.380, JP-2001.136651, CN-2.687.913 (Y), CN-2.687.914 (Y), CN-201.877.773 (U), CN-2.852.156 (Y), or JP-S-61.73105 (A), but these systems do not allow to provide an underwater connection to electrically connect together tightly three subsea electrical cables.

Also, the invention proposes a submarine connection system for electrically sealingly connecting at least three high voltage or very high voltage submarine electric cables, of the type in which:

- The electrical cables each comprise a main conductor surrounded by at least one main insulating sheath, itself surrounded by a metal armor;

each electrical cable has a connection end at which the main conductor has an apparent end projecting axially beyond a corresponding end of the main insulating sheath and one end of the metallic armor;

and of the type in which the system comprises:

an outer cage which delimits a connection space, the cage comprising cable passage inlets, provided to allow the passage of the electrical cables to be connected together electrically;

a connection connection, received in the connection space and comprising a conductive connection electrode which has a junction node from which at least three branches extend, each of which branch is intended to be electrically connected to the connection end of one of the electric cables to be connected together electrically; characterized in that

each of said at least three branches of the conductive electrode comprises a male terminal portion;

each of said at least three branches of the electrode is electrically connected, within the connection space, to the connection end of one of the electric cables at a connection zone around which is mounted a connection sleeve comprising an outer tubular sleeve of pre-molded insulating material which has a bore opening at its two opposite axial ends for, in mounted position, receiving, by each end, on the one hand the terminal male portion of one of the branches of the conductive electrode and secondly the connecting end of one of the electric cables.

According to other optional features of the invention, taken one by one or in combination:

- The connection sleeve may comprise, axially in its center, a conductive inner tubular sleeve which is flush radially inwardly in the internal bore.

- The connection sleeve may comprise at each axial end a conductive ring.

- The connection connection may comprise an insulating layer which surrounds the junction node of the electrode and outside which the male end portions of said at least three branches of the electrode emerge while being visible.

The insulating layer which surrounds the junction node of the electrode may be made by molding in a polymer material.

The insulating layer which surrounds the junction node of the electrode may be at least partially covered with an electrically conductive layer. The insulating layer which surrounds the junction node may comprise branches which extend around an upstream part of each branch of the conductive electrode and which are each engaged in the internal bore of one of the connection sleeves.

- The end of the main insulating sheath of each of the electric cables can be engaged in the bore of one of the connection sleeves.

- The connection electrode can be made by molding conductive material.

- The main insulating sheath of the electrical cables to be connected together may be an extruded sheath.

- The electrical cables to be connected together may comprise, between the main insulating sheath and the metal armor, an electrically conductive waterproof screen sheath; the system may comprise a conductive screen envelope which sealingly encapsulates the junction connector and each of the connection sleeves which respectively surround the connection zone of each of said at least three branches of the electrode, and the envelope may be connected sealingly and electrically conductive with the shield sheath waterproof electric cables to be connected together.

The conductive shield may comprise a conductive shield shell which encapsulates the junction node of the connector, and, for each connecting sleeve, a conductive sealable capsule which is arranged around the connection sleeve and which at one end axial axis of the sleeve, is sealed and electrically conductive with the sealed screen sheath of the corresponding electric cable, and at the other axial end of the sleeve, is connected sealingly and electrically with the conductive screen shell.

- The waterproof screen shell that encapsulates the junction node of the connection fitting can be preformed prior to assembly of the joining system. - The weave of each electrical cable to be connected together can be mechanically linked to the external cage of the system.

- The weave of each electrical cable to be connected together can be mechanically linked to the external cage of the system at the corresponding cable entry.

- The outer cage can be electrically conductive, and the armor of each electrical cable can be mechanically linked and electrically connected to the outer cage of the system.

- The system may comprise, at each cable passage entrance of the outer cage, a curvature limiter of the electric cable.

- The curvature limiter of the cable may comprise a cable guide tube of elastomeric material which is mechanically connected to the outer cage, which extends outside thereof, and which has an internal bore which is traversing axially along the axis of the tube, an axial end of the tube being arranged opposite the cable passage entrance.

- The outer cage can be made of at least two parts, each part having at least one cable entry, and the two parts can be mechanically linked to one another.

- The two parts of the outer cage can be electrically conductive and electrically connected to each other.

Various other characteristics appear from the description given below with reference to the accompanying drawings which show, by way of non-limiting examples, embodiments of the subject of the invention.

Figure 1 is a cross-sectional view of an embodiment of an underwater electric cable may be electrically connected by means of a system according to the invention.

Figure 2 is a schematic external view of an exemplary embodiment of a system according to the invention.

Figure 3 is a schematic view in partial section, by a longitudinal plane, of the main components of an exemplary embodiment of a system according to the invention. Figure 4 is another schematic view in another partial sectional view through a longitudinal plane of a detail according to view IV of FIG. 3 illustrating a connection of one of the cables by means of a pre-molded junction according to an embodiment of a system according to the invention.

Figure 5 is a schematic sectional view of an exemplary embodiment of a connection connector for a system according to the invention.

Figure 6 is a schematic perspective view of an exemplary embodiment of a connection connector for a system according to the invention and components of a sealed screen shell for a system according to the invention.

It is illustrated schematically in FIG. 2 a submarine connection system 20 for submarine electrical cables, including submarine electrical cables for high voltage or very high voltage electrical circuits. Such a system is intended to electrically connect sealingly at least three subsea electrical cables, for example a first cable 10 ', a second cable 10 "and a third cable 10"', in which are likely to circulate nominal currents. , that is to say established currents, at a voltage greater than 1000 V AC or 1500 V DC, or even under very high voltage, that is to say a voltage greater than 50,000 V in alternating current or 75,000 V in direct current. The invention will be more particularly described in the context of a high or very high continuous electrical voltage. The connection system according to the invention must be able to withstand electrical currents whose nominal operating intensity can reach several hundred amperes, or even a thousand amperes or more.

In the illustrated example, the connection system is intended to connect together only three high voltage electrical cables. However, the invention also covers connection systems for connecting four, five, or more high voltage electrical cables together insofar as such systems are actually provided for at least three electrical cables, with additional means of connection. for the additional cables beyond three, which can in particular be replicated from the connection elements that will be described for each of the three connections in the illustrated examples.

In the illustrated example, the connection system 20 is provided for a connection having a geometric Y configuration, the two branches of the Y being parallel. At the output of the connection system, each of the cables has an axial direction A ', A ", A'", the three axial directions defining the geometric configuration of the connection system. The invention could be implemented with a T configuration, or a star configuration with three branches to

120 °, etc. In the illustrated example, the axial directions A ', A ", A'", cables to be connected together are coplanar, but non-coplanar configurations are also possible.

It should be noted that the drawings are diagrammatic and that, to take account of the constraints of the high voltage and / or the very high voltage, care should be taken to avoid sharp angles.

In the following description, each of the three cables is of the type described in the preamble of the present application, with reference to FIG. 1. It is therefore cables provided for a high voltage or very high DC voltage, having an extruded main insulation sheath 14. However, the three cables are not necessarily all identical, neither in their constitution, nor in the materials of the various components of each cable, nor in the electrical dimensioning of each of the components of the cable.

However, the electrical cables each comprise a main conductor 12, strong conductor, surrounded by at least one main insulating sheath 14 itself surrounded by a metal armor 18. In the example shown, the electric cables each have more, between the main insulating sheath 14 and the metal armor 18, a screen sheath 16 electrically conductive. Furthermore, between the screen-tight sheath 16 and the armor 18, there is provided a protective layer 17, which can be strong conductive, weak conductive or insulating. These components may be as described above in the preamble of this application. Cables may have other components.

As can be seen in particular in Figs. 3 and 4, each electrical cable to be connected together 10 ', 10 ", 10"' has a connection end at which the main conductor 12 has an exposed end projecting axially from a corresponding end of the main insulating sheath 14 and one end of the metal armor 18. For this, in order to achieve a connection according to the invention, the various components that surround the conductor 12 are removed over a certain length. In a known manner, these various components that surround the conductor 12 are thus removed over stepped lengths. This makes it possible, for example, to make apparent, when the cable is considered in isolation, successively an apparent end of the conductor 12, an apparent end of the main insulating sheath 14, an apparent end of the outer shielding layer 15, an apparent end of the protection 16, and an apparent end of the armor 18.

The connection system 20 according to the invention comprises an outer cage 22 which delimits a connection space. The outer cage 22 is, in the embodiment shown, the outermost part of the connecting system 20. This outer cage 22 is generally made essentially of metal materials, for example steel. It can be covered with a paint, a varnish, a coating or a layer of protective material. This outer cage 22, which will be seen later that it is advantageously made in two parts 22a, 22b, constitutes a protective envelope for the connecting elements located inside, and a first barrier against the penetration of water. and marine microorganisms, even if the outer cage 22 is not necessarily sealed. The outer cage 22 provides the rigidity and mechanical tension necessary for the system 20 to be installed in deep water. The outer cage 22 has cable entry inlets, provided to allow passage of the electrical cables to be electrically connected, so that the cable connection ends can be received within the connection space. In the illustrated example, there are as many cable entry entrances as electrical cables to be connected together, each cable entry entrance accommodating only one of the electrical cables to be connected together.

For example, the outer cage 22 can be made in the form of two half-shells 22a, 22b, each half-shell being closed on all sides except at a junction plane P. In this junction plane P, each half-shell 22a, 22b has an opening delimited by a peripheral bearing edge, the two peripheral bearing edges of the two half-shells 22a, 22b being provided to bear against each other, preferably according to a closed and continuous contour to ensure a certain tightness. At the level of this peripheral bearing edge, the half-shells may comprise complementary flanges 24a, 24b making it possible to assemble the two half-shells together, for example by means of bolts and / or by welding, and / or any other means of assembly. Once thus assembled, the two half-shells 24a, 24b delimit the connection space which, apart from the cable entry entries, is preferably closed.

In the illustrated example, each half-shell 22a, 22b has a bottom wall 26a, 26b, opposite to the peripheral bearing edge. For example, the bottom walls are parallel to one another and form opposite ends of the outer cage 22. In the illustrated example, a first half-shell 22a has, in its bottom wall 26a, an inlet passage for the first electrical cable 10 ', while the second half-shell 22b comprises, in its bottom wall 26b, two cable entry entries respectively for the second electrical cable 10 "and the third electrical cable 10'" . At the heart of the connection system according to the invention, within the connection space, there is a connection connection 30 which is more particularly illustrated in section in isolation in FIG. 5.

The connection connector 30 comprises a conductive connection electrode 32 which has a junction node 34 from which three branches 36 ', 36 ", 36"' extend, each branch of which is intended to be electrically connected to the end of the connector. connecting one of the electrical cables 10 ', 10 ", 10"' to be connected together electrically. The junction node 34 provides electrical continuity between the branches 36 ', 36 ", 36"' of the electrode 32.

The electrode 32 is preferably made of a strong conductive material, in particular a metallic material, for example copper or aluminum or an alloy based on copper or aluminum. The electrode 32 has the same function as the conductor in an electric cable. It can therefore be performed using the same techniques and / or the same materials. The electrode 32 is advantageously in one piece, for example molded in one piece. It can, however, be made of several parts electrically connected. The conductive connection electrode 32 provides electrical continuity between the main conductors 12 of the electrical cables 10 ', 10 ", 10"' to be connected together electrically.

In the illustrated example, it has a Y-shaped geometry corresponding to the overall configuration of the connection system. Each of the three branches 36 ', 36 ", 36"' of the conductive electrode comprises a male end portion 38. In the illustrated example, each of the branches is substantially cylindrical and its male end portion determines an axial orientation of the branch.

The connection connection 30 comprises an insulating layer 40 which surrounds the junction node 34 of the electrode 32. The male end portions 38 of the three branches of the electrode emerge while being visible outside the insulating layer. These male end portions 38 which emerge preferably have a length similar to that of the apparent end of the conductor of an electrical cable 10 to be connected together. In the illustrated embodiment, the insulating layer 40 has at least three branches, which extend from the joining node 34 around an upstream portion of the branches 36 ', 36 ", 36"', but outside which the male end portions 38 of the three branches of the electrode emerge while being visible. Preferably, the insulating layer 40 which surrounds the junction node 34 of the electrode 32 is made by molding a polymer material. It may for example be made of EPDM type material or silicone type.

In the example shown, the connection connection 30 has, on the insulating layer 40 surrounding the junction node 34 of the electrode 32, including on its branches, an electrically conductive layer 42 which covers the insulating layer. . This layer 42 preferably has properties similar to those of the outer shield layer 15 of the electrical cable to be connected together. Thus, it is preferably a weak conductor. The conductive layer 42 which covers the insulating layer 40 of the connection connection 30 can thus for example be made of a polymer material loaded with conductive particles. It may for example be made by overmolding around the insulating layer 40. However, the conductive layer 42 does not completely cover the insulating layer 40 of the connection connection 30 and instead leaves in a downstream portion of the branches 36 ', 36 ", 36" ', apparent ends of the insulating layer 40.

The connection fitting 30, comprising the electrode 32, the insulating layer 40, and possibly the conductive layer 42, is a part which is prefabricated before the connection system is assembled.

In the illustrated example, the axial orientations of the branches 36 ', 36 ", 36"' of the connection electrode 32 correspond to the three axial directions A ', A ", A'" defining the geometric configuration of the connection system.

In a connection system according to the invention, each of the three branches of the electrode is intended to be electrically connected, inside the connection space delimited by the outer cage 22, with the connecting end of one of the electrical cables to be connected together 10 ', 10 ", 10"'. For this, each connection end of an electrical cable to be connected together is presented with its axial direction aligned with the axial direction of the branch of the corresponding electrode so that the male end portion 38 of the branch 36 ', 36 ", 36"'of the connection electrode and the cable connection end, in particular the apparent end of the conductor 12, are presented end-to-end.

In a connection system according to the invention, each of the connections between the connection end of a cable to be connected together and the male terminal portion 38 of the corresponding branch 36 ', 36 ", 36"' of the connection 32 is made by implementing a pre-molded junction, for example of a type similar to that described in patent document US Pat. No. 8,097,807-B2.

Indeed, each of the connections between the connection end of a cable to be connected together and the male terminal portion 38 of the corresponding branch 36 ', 36 ", 36"' has a connecting zone which corresponds, in the axial direction relevant, the length which includes including the male end portion 38 and the apparent end of the conductor 12 which are presented end to end and which are electrically connected. More precisely, the connection zone corresponds to the end zone of the cable to be connected together in which the conductor 12 is devoid of its main insulating sheath 14 and to the end zone of the branch of the connection electrode 32 which is devoid of insulating layer 40.

A pre-molded junction uses a connection sleeve 44 comprising an outer tubular sleeve 46 of pre-molded insulating elastomeric material which has a bore opening at its two opposite axial ends. In the mounted position, the connecting sleeve 44 is arranged around the connection zone, so as to provide electrical insulation preferably similar to the electrical insulation provided by the main insulating sheath 14 of the cable 10 or by the insulating layer 40 of the connection fitting 30. In the mounted position, the internal bore of the sleeve The connection piece receives, by each end, on the one hand the male terminal portion 38 of one of the branches of the conductive electrode and, on the other hand, the connection end of one of the electric cables. More specifically, this bore receives the end zone of the cable to be connected together in which the conductor 12 is devoid of its main insulating sheath 14 and the end zone of the branch of the connection electrode which is devoid of insulating layer 40. The outer tubular sleeve 46 has an axial dimension greater than that of the connection zone. Indeed, as can be seen in particular on the Fïg. 4, the outer tubular sleeve 46 of insulating elastomeric material extends in the axial direction so as to cover not only the connection zone but also so that one of its ends covers at least partly the apparent end of the main insulating sheath 14 of the cable 10 while the other of its ends covers one end of a corresponding branch of the insulating layer 40 of the connection fitting 30. For each connection between the connection fitting 30 and a cable to be connected together, the branch of the insulating layer 40 thus has one end engaged in the internal bore of the corresponding connecting sleeve. Similarly, for each connection between the connection fitting and a cable to be connected together, the end of the main insulating sheath 14 of the electrical cable is engaged in the bore of the corresponding connecting sleeve 30.

Thus, the outer tubular sleeve 46 provides continuity of electrical insulation at the connection area.

The internal diameter delimited by the connection sleeve 44, and in particular by its external tubular sleeve 46 is substantially equivalent or preferably very slightly less than the external diameter of the main insulating sheath 14 of the cable, and the external diameter of the end of the corresponding branch of the insulating layer 40 of the connection connection 30. This allows in particular to ensure a tight fitting of the connection sleeve on the main insulators and thus to ensure the best continuity of the electrical insulation. The tubular sleeve external 46 being made of elastomeric material, for example of the EPDM or silicone type, the diameter of its bore may adapt to some extent, by elastic deformation, to the diameter of the main insulating sheath 14 and / or the layer insulating 40.

The electrical connection between the conductor 12 and the male terminal portion 38 of the electrode 32 is made by any means known in the field of pre-molded junctions. Thus, this electrical connection can be made by welding. In the illustrated example, there is provided a conductive tubular crimping shell 48, for example made of metal, inside which the conductor 12 and the male terminal portion of the electrode are engaged, the ferrule then being crimped. a part on the conductor 12 and secondly on the male end portion 38. In both cases, such a connection provides both a mechanical connection and an electrical connection. Other connection modes may be provided for example by winding a conductive strip, for example a ribbon formed of a wire mesh. In the example illustrated, it can be seen that the ferrule 48 is received in a space which, in the connection zone, extends radially between the conductor 12 and the internal bore of the connection sleeve 30. In a known manner, this space can be filled by a filling material or a ring 49, of conductive material, preferably strong conductor.

In the illustrated example, the connecting sleeve 44 comprises an inner conductive tubular sleeve 50 which extends co-axially in the center of the outer tubular sleeve 46. In the example shown, the inner tubular sleeve 50 is flush radially inwards in the internal bore of the connection sleeve. The inner diameter of the inner tubular sleeve 50 may be smaller than that of the outer tubular sleeve 46. The inner tubular sleeve 50 is preferably a weak conductor. It may be an element made of a polymer material loaded with conductive particles. In some embodiments, the inner tubular sleeve 50 may be a separate part of the outer tubular sleeve 46. In this case, this separate part may be accommodated in a reservation. arranged in the inner diameter of the outer tubular sleeve 46. However, advantageously, the inner tubular sleeve 50 can be made in the form of a single piece with the outer tubular sleeve 46, the inner tubular sleeve then corresponding to a zone of the workpiece unique in which the elastomeric material is charged with conductive particles.

It will be noted that the diameters of the main insulating sheath 14 of the cable 10 and of the insulating layer 40 are not necessarily equal, and / or that the diameters of the main conductor 12 of the cable 10 and of the male terminal portion 38 of the electrode 32 are not necessarily equal. In this case, the connection sleeve 44 is adapted and has two axial portions whose diameters are adapted.

In the example shown, the connection sleeve 44 comprises, at each axial end, a conductive ring 52 which, in the same manner as the internal tubular sleeve 50, can be made in the form of an insert or a integrated part with the outer tubular sleeve 46. The conductive rings 52 axially extend the internal bore formed by the outer tubular sleeve 46. They are able to come electrically in contact, for one, with the outer screen layer 15 of the cable to connect the corresponding assembly, and for the other with the conductive layer 42 which covers the insulating layer 40 of the connection connector 30. In known manner, these conductive rings 52 can control the electric fields. The conductive rings 52 are preferably weak conductors; they are for example made of polymer material charged with conductive particles.

In the example illustrated, the electrical cables to be connected together 10 ', 10 ", 10"' each comprise a sealed screen sheath 16, for example lead or lead alloy, which protects the main insulating sheath 14 and the conductor 12 water and allows to homogenize the radial electric field generated by the passage of the current in the conductor 12 of the cable 10. To ensure continuity of this functionality through the connection system, the latter comprises a sealed screen envelope 54, 56, which encapsulates sealingly the connection fitting 30 and each of the connection sleeves 44 which respectively surround the zone of connection of each of said three branches of the electrode 32. This sealed screen envelope is connected sealingly and electrically with the sealed screen sheath 16 of each of the electrical cables to be connected together 10 ', 10 ", 10"'. The sealed screen envelope is preferably completely received in the connection space delimited by the outer cage 22. It delimits an internal volume that is sealed relative to the rest of the connection space. This sealed screen envelope includes, of course, cable entry openings, provided to allow the passage of electrical cables to be connected together electrically, so that the connection ends of the cables can be received inside the internal volume. Preferably, there are as many cable entry entrances as there are electrical cables to be connected together, each cable entry entrance accommodating only one of the electrical cables to be connected together.

The sealed screen envelope preferably has electrical properties similar to those of the sealed screen sheath 16 of the cables to be connected together. It is for example made of metal, for example lead or lead alloy, so preferably strong conductor material.

The sealed screen envelope could be made in the form of a part in only two separate parts along a junction plane, for example the plane of Figs. 3 and 4.

However, in the illustrated embodiment, the sealed screen envelope is made in several sections, each section possibly being made in several parts. Each section defines a portion of the internal volume of the sealed screen envelope, these portions being connected to one another. Thus, in the example illustrated, the screen envelope firstly comprises a section in the form of a conductive waterproof screen shell 54, which sealingly encapsulates the junction node 34 of the connection connection 30. The shell Waterproof screen 54 defines a portion of the internal volume of the waterproof screen envelope. This shell is a hollow part, for example formed in two parts 54a, 54b, which can be symmetrical on either side of a junction plane, for example the plane of Figs. 3 and 4 containing the axial orientations of the branches 36 ', 36 ", 36"' of the connection electrode 32. In the example shown, the sealed screen shell 54 has a shape complementary to that of the connection fitting 30, in The watertight screen shell 54 is in no-gap contact with the outer surfaces of the connection fitting 30.

The sealed screen envelope further comprises, for each connection sleeve 44, a section in the form of a conductive, preferably strong conductive, electroconductive sealing capsule 56, for example made of metal, which is arranged around the connecting sleeve 44 and which, at one axial end of the sleeve 44, is sealingly and electrically connected with the sealed screen sheath 16 of the corresponding electrical cable 10 ', 10 ", 10"', and at the other axial end of the sleeve 44, is sealed and electrically conductive with the sealed screen shell 54.

In the illustrated example, each sealed screen capsule 56 has a shape complementary to that of the connection sleeve 44, in this case a barrel shape with two openings 57 at each axial end. Each sealed screen capsule 56 is for example a hollow part. Preferably, each sealed screen capsule 56 is in gap-free contact with the outer surfaces of the connecting sleeve 44. A first of the axial openings 57 is a circular opening which is provided to surround the sealed screen sheath 16 of the cable 10 ', 10 " , 10 "'to be connected together. This axial opening can be connected in a sealed manner with the sealed screen sheath 16, by example by means of a circular weld around the sealed screen sheath 16. The second of the axial openings 57, opposite, is provided to cooperate with a corresponding interface area of the sealed screen shell 54. For this, each capsule waterproof screen 56 may be an initially cylindrical and tubular part whose axial openings 57 are, at the time of installation, deformed radially, as in a crimping, to come into contact respectively with the sealed screen sheath 16 and with the zone d ' corresponding interface of the waterproof screen shell 54.

Indeed, the sealed screen shell 54 has three interface areas 55 at which it is sealed and electrically conductive respectively with the three waterproof screen capsules 56 which, together with the waterproof screen shell 54, form the screen envelope waterproof. This connection is made for example by means of welds. The interface zones are formed, for example, of respective circular contact surfaces 57, 55 of the corresponding capsule 56 and of the shell 54.

Each sealed screen capsule 56 defines a portion of the internal volume of the sealed screen envelope which is connected, at the level of the corresponding interface area, with the portion of the internal volume defined by the sealed screen shell 54.

The sealed screen shell 54 is preferably preformed prior to assembling the joining system. It can be performed for example by molding, stamping or forging. It is the same for the waterproof screen capsules 56.

Furthermore, it is advantageously provided that the armor 18 of each electrical cable is mechanically connected to the outer cage 22 of the system. This makes it possible to prevent the mechanical stresses to which the cables 10 ', 10 ", 10"' are subjected, whether during installation or in service, to risk compromising the electrical connection between the cable conductors.

In the example illustrated, the armor 18 of each electrical cable 10 ', 10 ", 10"' is mechanically connected to the external cage 22 of the system at level of the corresponding cable entry entrance. For example, there is provided for each cable, a flange 58 which surrounds the cable and which mechanically connected to the armor 18. This connection may comprise a weld. It may also comprise a connection by clamping the strands of the armor 18 between two parts of the collar 58. In the example illustrated, the collar is illustrated as being received inside the connection space delimited by the cage 22. It could be arranged outside the cage. However, it is arranged outside the volume defined by the sealed screen envelope. The flange 58 is also fixed on the cage 22. Here, this attachment is provided around the corresponding cable passage entry. This attachment can be provided by bolts, for example distributed around the circumference of the cable entry entrance. This attachment may include a weld. The connection between the armor and the collar 58 and / or the attachment of the flange 58 to the cage 22 can be made as described in the document US Pat. No. 8,507,795.

Furthermore, the armor 18 of each electrical cable 10 ', 10 ", 10'" to be connected together is electrically connected to the external cage 22 of the system such that the outer cage 22 ensures the continuity of the electrical functionality of the Thus, the armor 18 of each electrical cable is mechanically connected and electrically connected to the outer cage of the system. Insofar as the outer cage 22 is made in two parts 22a, 22b or more, it is expected that the two parts 22a, 22b or more of the outer cage 22 are electrically conductive, preferably strong conductors, and electrically connected. one to the other.

The electrical connection and the mechanical connection between the armor 18 and the outer cage 22 are preferably combined, i.e. made by the same components. In the example illustrated, the electrical connection between the armor 18 of a cable 10 ', 10 ", 10"' and the outer cage 22 is preferably made through the flange 58 which provides the mechanical connection.

In the illustrated example, the connection system comprises, at each cable passage entrance of the cage, a limiter of curvature 60 of the corresponding electrical cable 10 ', 10 ", 10"', this to prevent damage to the cable, at its entry into the system, by excessive bending.

According to the illustrated example, the curvature limiter 60 of the cable comprises a cable guide tube 60, which may be made of elastomeric material, for example of the EPDM or silicone type, and which is mechanically linked to the cage. The guide tube 60 extends outside the cage 22, and it has an internal bore which is traversing axially along the axis of the tube, an axial end of the tube being arranged facing the passage entrance of the tube. cable.

In the illustrated example, the diameter of the tube decreases away from its end by which it is fixed on the cage. It is therefore understood that the guide tube 60 surrounds and reinforces the cable in its portion which is located just outside the outer cage 22 of the connection system. The degree of reinforcement decreases with the diameter of the guide tube away from the outer cage in the direction of the cable 10 ', 10 ", 10"'. Alternatively, there could be a curvature limiter which would be arranged as the guide tube, outside the cage from the cable entry and around the cable, but having a shape similar to that of a trumpet flag. Such a trumpet horn curvature limiter may be made of polymer material or metal.

Moreover, to further strengthen the electrical insulation, it is advantageously provided that the connection connection 30 can be received inside an insulating block which is contained in the connection space. In the example illustrated, this insulating block is made by filling the connection space with an insulating material and which covers the connection connection 30 and the sealed screen shell 54, but also preferably all the components contained in the space of connection, including the connection sleeves 44 and the waterproof screen capsules 56. This insulating material may be bitumen or an insulating polymer resin.

The invention is not limited to the examples described and shown because various modifications can be made without departing from its scope.

Claims

1 - Submarine connection system for electrically sealingly connecting at least three electric cables (10 ', 10 ", 10"') submarines high voltage or very high voltage, of the type in which:

- The electrical cables each comprise a main conductor (12) surrounded by at least one main insulating sheath (14), itself surrounded by a metal armor (18);

- each electrical cable has a connection end at which the main conductor (12) has an exposed end protruding axially from a corresponding end of the main insulating sheath (14) and one end of the metallic armor ( 18);

and of the type in which the system comprises:

- An outer cage (22) defining a connection space, the cage having cable passage entries, provided to allow the passage of electrical cables to be connected together electrically;

a connection connector (30) received in the connection space and comprising a conductive connection electrode (32) having a junction node (34) from which at least three branches (36 ', 36 ") extend; , 36 "'), each branch of which is intended to be electrically connected to the connection end of one of the electric cables to be connected together electrically;

characterized in that

each of said at least three branches (36 ', 36 ", 36"') of the conductive electrode (32) comprises a male end portion (38);

each of said at least three branches of the electrode is electrically connected, within the connection space, to the connection end of one of the electric cables at a connection zone around which a connection sleeve (44) having an outer tubular sleeve (46) pre-molded insulating material which has a bore opening at its two opposite axial ends for, in mounted position, receiving, by each end, on the one hand the male end portion (38) of one of the branches of the conductive electrode and on the other hand the connection end of one of the electric cables.

2 - subsea connection system according to claim 1, characterized in that the connecting sleeve (44) comprises, axially in its center, an inner tubular sleeve (50) which is flush radially inwardly in the bore internal.

3 - subsea connection system according to any one of claims 1 or 2, characterized in that the connecting sleeve comprises at each axial end a conductive ring (52).

4 - underwater connection system according to any one of the preceding claims, characterized in that the connection connection (30) comprises an insulating layer (40) which surrounds the junction node (34) of the electrode (32). ) and outside which the male end portions (38) of said at least three branches of the electrode emerge being apparent.

5 - underwater connection system according to claim 4, characterized in that the insulating layer (40) which surrounds the junction node of the electrode is made by molding polymer material.

6 - underwater connection system according to any one of claims 4 or 5, characterized in that the insulating layer which surrounds the junction node of the electrode is covered at least partially with a conductive layer of electricity (42).

7 - subsea connection system according to any one of claims 4 to 6, characterized in that the insulating layer (40) surrounding the junction node has branches that extend around an upstream portion of each branch (36 ', 36 ", 36"') of the conductive electrode (32) and which are each engaged in the internal bore of one of the connection sleeves (44). 8 - underwater connection system according to any one of claims 4 to 7, characterized in that the end of the main insulating sheath (14) of each of the electric cables is engaged in the bore of one of the sleeves connection (44).

9 - underwater connection system according to any one of the preceding claims, characterized in that the connection electrode (32) is made by molding conductive material.

10 - subsea connection system according to any one of the preceding claims, characterized in that the main insulating sheath (14) of the electrical cables to be connected together (10 ', 10 ", 10"') is an extruded sheath.

11 - Underwater connection system according to any one of the preceding claims, characterized in that the electrical cables (10 ', 10 ", 10"') to be connected together comprise, between the main insulating sheath (14) and the metal armor (18), an electrically conductive sealed shield sheath (16), in that the system (20) has a conductive shield (54, 56) which sealingly encapsulates the joint (30) and each of the connecting sleeves (44) which respectively surround the connection area of each of said at least three branches of the electrode, and in that the envelope (54, 56) is sealingly connected and electrically conductive with the waterproof screen sheath (16) of the electric cables to be connected together (10 ', 10 ", 10"').

12 - Underwater connection system according to claim 11, characterized in that the conductive screen envelope comprises a conductive screen shell (54) which encapsulates the junction node (34) of the connection fitting (30), and for each connecting sleeve (44), a conductive sealing screen capsule (56) which is arranged around the connecting sleeve and which, at one axial end of the sleeve, is electrically and sealingly connected with the leakproof screen sheath (16). ) of the corresponding power cable (10 ', 10 ", 10"'), and, the other axial end of the sleeve is sealed and electrically conductive with the conductive shield shell (54).

13 - underwater connection system according to claim 12, characterized in that the waterproof screen shell (54) which encapsulates the junction node (34) of the connection fitting (30) is preformed before the assembly of the junction system (20).

14 - underwater connection system according to any one of the preceding claims, characterized in that the armor (18) of each electrical cable to be connected together (10 ', 10 ", 10'") is mechanically connected to the external cage (22) of the system (20).

15 - subsea connection system according to any one of the preceding claims, characterized in that the armor (18) of each electrical cable to be connected together (10 ', 10 ", 10"') is mechanically connected to the external cage (22) of the system (20) at the corresponding cable entry.

16 - underwater connection system according to any one of the preceding claims, characterized in that the outer cage (22) is electrically conductive, and in that the armor (18) of each electric cable is connected mechanically and electrically connected to the outer cage (22) of the system (20).

17 - Underwater connection system according to any one of the preceding claims, characterized in that it comprises, at each cable passage entrance of the outer cage (22), a curvature limiter (60) of the electric cable.

18 - Underwater connection system according to claim 17, characterized in that the curvature limiter of the cable comprises a guide tube (60) of elastomeric material cable which is mechanically connected to the outer cage (22), which extends outside of the latter, and which has an internal bore which is traversing axially along the axis of the tube, an axial end of the tube being arranged opposite the cable entry. 19 - subsea connection system according to any one of the preceding claims, characterized in that the outer cage (22) is formed in at least two parts (22a, 22b), each portion having at least one cable entry entrance , and in that the two parts are mechanically linked to each other.

20 - subsea connection system according to claim 19, characterized in that the two parts (22a, 22b) of the outer cage (22) are electrically conductive and electrically connected to each other.