Electrical connection device

Abstract

One aspect of the invention relates to an electrical connection device comprising a cable (10) and an electrical connector (30) connected to one end of the cable (10), wherein the cable is a cable with a coaxial structure comprising a conductive core (11) surrounded successively by a first semiconductor layer (12), an insulating layer (13) and a second semiconductor layer (14).

Description

DESCRIPTION TITLE: Electrical connection device TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of electrical connection devices, in particular intended for use in aircraft.

[0002] In particular, the invention relates to an electrical connection device making it possible to avoid the occurrence of damage to installations due to areas of electric field reinforcement (such as partial discharges, dielectric breakdown or even damage due to space charges). TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various carbon emission restrictions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new aircraft types and those currently in operation, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been mobilizing for several years now to contribute to the fight against climate change.

[0004] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental impacts with the aim of improving the energy efficiency of aircraft.

[0005] Consequently, the Applicant is constantly working to reduce its climate impact by using methods and operating virtuous development and manufacturing processes and minimizing greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0006] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to ensure propulsion, and, as an essential complement to technological progress, aeronautical biofuels.

[0007] In particular, the present invention can be used in the context of electric or hybrid propulsion.

[0008] Electric or hybrid propulsion is one of the current challenges in the aeronautics sector, with the aim of reducing CO2 emissions. Such propulsion systems require high-power electrical networks to power aircraft engines.

[0009] High electrical power is achieved by combining high voltages at high frequencies with high currents. For example, electrical equipment is subjected to DC, AC, or Pulse Width Modulation (PWM) voltages of up to 1000 V, currents of 300 A, and electrical frequencies of up to 1500 Hz. Voltage extremes can reach 3000 V, while current and frequency extremes can reach 1000 A and 3000 Hz, respectively.

[0010] In the terrestrial domain, it is known to use coaxial structure cables, such as that shown in Figures 1 a and 1 b, to conduct high electrical voltages. In particular, Figure 1 a represents such a cable 10 with coaxial structure in the lengthwise direction, and Figure 1 b represents a front view of the cable. The cable 10 thus comprises a conductive core 11 (in an electrically conductive material), covered with successive layers: a layer 12 (called internal semi-conductive layer) of semi-conductive material, a layer 13 of insulating material, a layer 14 (called external semi-conductive layer) of semi-conductive material, a layer 15 of conductive material called a connection layer (for example a grounding braid) for connection to the reference potential of the layer 14 of semi-conductive material, and finally a layer 16 of mechanical and / or hermetic protection (sheath).The connecting layer 15 can be sized to additionally provide a function of. electromagnetic shielding (EMI shielding). The material of the inner 12 and outer 14 semiconductor layers is typically an electrically insulating material loaded with conductive particles, for example carbon black particles, carbon nanotubes, metallic additives, etc. These coaxial structure cables are then combined in an electrical harness, to transmit electrical power from one electrical equipment to another via connection systems such as electrical connectors, terminal block assemblies, etc.

[0011] Coaxial structure cables are currently used in the terrestrial domain, but their structure is adapted to the constraints of the aeronautical field. However, the coaxial cable connection solutions currently used in the terrestrial domain are not adapted to the constraints of the aeronautical field. Indeed, the electrical wiring must be able to withstand high voltages, as mentioned above, but also significant pressure variations (due to large altitude variations) and temperature variations. In particular, the electrical wiring must be able to be used both in a "normal" pressure environment - i.e. close to atmospheric pressure (pressurized area of the aircraft, whose pressure is between 750 mBar and 1 Bar) - and in a low pressure environment (unpressurized area, the pressure depends mainly on the flight altitude and can be lower than 100 mBar).

[0012] When connecting the cable 10 to the connection system, the outer semiconducting layer 14 must be removed over a certain length. The interface between the insulating layer 13, the outer semiconducting layer 14 and the ambient air is called the "triple point", and corresponds to an area in which an electric field reinforcement forms. This electric field reinforcement can cause physical phenomena (air breakdown, dielectric breakdown of the insulator, charge displacement in the insulator, etc.) which can lead to failure of the insulation system. The electric field reinforcement in the triple point area is all the more important since:

[0013] - the thickness of the insulating layer 13 is low, which is the case in the aeronautical field, for reasons of mass saving and flexibility of the cable;

[0014] - the cable is subjected to high temperatures and low pressures, which is also the case in the aeronautical field (with significant variations during operation).

[0015] Furthermore, the electric field reinforcement is amplified when the thickness of the insulating layer 13 is small, which is generally the case in the aeronautical field, for reasons of mass saving and flexibility of the cable. It is also noted that, when the external semiconducting layer 14 is removed, this may have the undesired consequence that a portion of the insulator may also be removed, for example due to poorly adjusted tooling, poor concentricity of the insulators, ovalization, etc., which has the effect of amplifying the electric field reinforcement.

[0016] Furthermore, when the outer semiconductor layer 14 is removed, a portion of the insulator may be subject to electrical phenomena such as spike effects which may provide additional degradation.

[0017] Furthermore, since the insulation thickness is sized for operation with the external semi-conducting layer 14, when this layer is removed, the insulation alone does not guarantee the level of dielectric performance necessary for the application.

[0018] There is therefore a need for cabling adapted to the constraints of the aeronautical field, which makes it possible to avoid degrading electrical phenomena such as partial discharges, dielectric breakdown, degradation linked to space charges or even to limit the impact of peak effects. SUMMARY OF THE INVENTION

[0019] The invention provides a solution to the problems mentioned above, by proposing an assembly of components which, when switched on, allows the electric field and the electric potential to be limited to values which do not trigger physical phenomena which could damage the electric circuit, such as partial discharges, dielectric breakdowns, electric arcs, etc.

[0020] Furthermore, the invention offers a solution to the problems mentioned above by proposing an assembly of components which, when switched on, limits the impact of external electrical phenomena such as peak effects, etc.

[0021] One aspect of the invention thus relates to an electrical connection device comprising a cable and an electrical connector connected to one end of the cable, in which the cable is a coaxial structure cable comprising a conductive core surrounded successively by a first semi-conductor layer, an insulating layer and a second semi-conductor layer, in which the cable comprises a first cable portion and a second cable portion, in which the first cable portion is a portion adjacent to said end on which at least part of the second semi-conductor layer is absent. The device may thus comprise:

[0022] a thickness of electric field dimmer material covering at least a portion of the insulating layer of said first cable portion and extending over a portion of the second semiconducting layer of said second cable portion, said thickness of electric field dimmer material having no point of contact with said electrical connector;

[0023] a thickness of insulating material covering the thickness of electric field dimmer material and making contact with the second semi-conducting layer of said second cable portion and with said electrical connector.

[0024] It is understood that the term "thickness" refers to a layer of material. This difference in terminology is solely intended to distinguish between the components of the cable and the additional components of the connection device, without causing confusion when reading.

[0025] In the following, the first semiconductor layer is also called the inner semiconductor layer, and the second semiconductor layer is also called the outer semiconductor layer.

[0026] An "electrical connector" is a component or set of components intended to connect several electrical cables in a circuit or an electrical cable with equipment, in order to supply several electrical devices or equipment. For example, the electrical connector may be a male / female plug-in connector, a terminal, a junction or an extension (also called "splices").

[0027] By "adjacent portion" is meant a portion of the cable one end of which corresponds to the end connected to the electrical connector. The first portion is thus a portion of the cable one of whose ends is connected to the electrical connector, and on which at least part of the second semiconducting layer has been removed. The second semiconducting layer may therefore have been completely removed over this entire first portion of cable, or only over a part (also called a “window” in the following) of this first portion of cable.

[0028] By "electric field dimmer material" (also called "potential dimmer material") is meant a material whose physical properties, in particular electrical conductivity and dielectric permittivity, make it possible to obtain a more homogeneous electric field gradient or electric potential. Such a gradient makes it possible to avoid an electric field reinforcement, thus reducing the stresses on the insulator which can lead to breaks in the insulation system. The physical properties of the material can be constant or variable. The variability of the properties can be geometric thanks to a change in the density of the particles which induce the change in the property of said material. The variability of the properties can be physical thanks to the addition of particles whose physical characteristics conductivity and / or permittivity change according to the value of the electric field.

[0029] In embodiments, the thickness of insulating material may be covered with a conductive connection layer extending over the second semiconductive layer of said second cable portion and over at least a portion of the electrical connector.

[0030] In these embodiments, there is no intermediate component between the thickness of insulating material and the conductive connection layer.

[0031] Alternatively, the thickness of insulating material is covered with a thickness of semiconducting material in contact with the second semiconducting layer of said second portion of cable.

[0032] In these embodiments, a thickness of semiconductor material is added. This advantageously makes it possible to reduce the thickness of the insulating material, while retaining good properties for limiting the electric field values at the junctions between the parts of the cable where the second semiconductor layer has been removed and the parts of the cable where the second semiconductor layer has not been removed.

[0033] Furthermore, this advantageously allows the thickness of the insulating material to be reduced, while maintaining good properties for limiting the electric field and the electric potential to values that do not trigger physical phenomena that could damage the electrical circuit, such as partial discharges, peak effects, etc.

[0034] In particular, the thickness of semiconductor material may cover the thickness of insulating material and extend onto the second semiconductor layer of said second cable portion and extend to a conductive part of the connector.

[0035] In these embodiments, the thickness of semiconductor material may be covered with a conductive connection layer extending over the second semiconductor layer of said second cable portion and over the conductive portion of the electrical connector.

[0036] This conductive connection layer makes it possible in particular to connect the second semiconductor layer to a ground reference along its entire length.

[0037] Further, in embodiments, the first cable portion comprises a first portion on which the second semiconductor layer is present, and a second portion on which the second semiconductor layer is absent, wherein the thickness of electric field dimming material partially covers the second portion of the first cable portion, the thickness of electric field dimming material further extending onto the first portion of the first cable portion.

[0038] In these embodiments, the second semiconductor layer has been removed only over a window not adjacent to the end of the cable connected to the connector. This allows the second semiconductor layer to be removed over a shorter length, which has advantages in terms of implementation.

[0039] For example, the thickness of electric field dimmer material can be in:

[0040] - an insulating material having a relative permittivity greater than or equal to 10 ;

[0041] - an insulating material with controlled electrical conductivity;

[0042] - a semiconductor material; and / or

[0043] - a material having an electrical conductivity dependent on an electric field.

[0044] It is understood that the electric field dimmer material may be a material combining several characteristics cited above.

[0045] The concept of insulating material defines an electrically insulating material, that is to say that it has low electrical conductivity (generally less than 10' 6 S / m) which allows it to have a strong resistance to the passage of electric current.

[0046] An "insulating material with controlled electrical conductivity" is a material whose electrical conductivity can be intentionally modified, adjusted, or regulated according to specific needs (for example, a semiconductor, which is a material to which particles have been added to increase its electrical conductivity, or a material that will have temperature-dependent conductivity). In other words, this electrical property can be deliberately modulated to meet needs. Modification of conductivity can be achieved by methods such as surface coating, integration of particles, application of electric or magnetic fields, or by controlling environmental conditions such as temperature. This allows the electrical properties of the material to be adapted.

[0047] A semiconductor material is a material that has an electrical conductivity that lies between that of conductors (e.g., metals such as copper) and electrical insulators (usually a range from 10' 6 S / m at 10 4 S / m).

[0048] For example, a material with a relative permittivity greater than or equal to 10 may be a material to which particles, for example, of AI2O3, SiO2, TiO2 or SrTiO3 have been added.

[0049] Examples of materials with controlled electrical conductivity or semiconductor materials are: carbon black, nanotubes, etc.

[0050] For example, a material with electrical conductivity dependent on an electric field may be a material to which microvaristors have been added zinc oxide (ZnO) or silicon carbide (SiC) particles or antimony-doped tin oxides (ATO - SnO2 Sb2O3).

[0051] Another aspect of the invention relates to an electrical connector for connection to a cable end, the connector comprising a conductive portion, the connector further comprising a thickness of electric field dimming material and a thickness of insulating material, wherein the thickness of insulating material is in contact with the conductive portion, wherein the thickness of insulating material completely covers the thickness of electric field dimming material, said thickness of electric field dimming material having no contact points with the conductive portion, wherein the connector comprises a recess for receiving said cable end, the recess passing through the thickness of insulating material and the thickness of electric field dimming material, wherein said thickness of electric field dimming material comprises a protrusion for receiving an outer layer of the cable.

[0052] According to this aspect of the invention, the thickness of electric field dimmer material and the thickness of insulating material are directly integrated into the connector. The cable (after removal of a part of the second semiconducting layer) can then be directly connected to this connector, and the wiring thus formed retains the properties of the above connection device.

[0053] Another aspect of the invention relates to an electrical connection component comprising a thickness of electric field dimming material and a thickness of insulating material, wherein the thickness of insulating material completely covers a surface of the thickness of electric field dimming material, wherein the electrical connection component comprises a recess for receiving a cable end, the recess passing through the thickness of insulating material and the thickness of electric field dimming material, wherein said thickness of electric field dimming material comprises a projection for receiving an outer layer of the cable.

[0054] Further, the above electrical connection component may comprise a thickness of semiconductor material covering the thickness of insulating material.

[0055] Such an electrical connection component may be connected to a cable as defined above, or to an electrical connector (in particular, a conventional electrical connector).

[0056] Another aspect of the invention relates to a kit comprising a connector as defined above and a coaxial structure cable comprising a conductive core surrounded successively by a first semiconducting layer, an insulating layer and a second semiconducting layer, in which the cable comprises a first cable portion and a second cable portion, in which the first cable portion is a portion adjacent to said end on which the second semiconducting layer is absent, in which, when the cable is connected to the connector, the second semiconducting layer is inside the projection of the thickness of electric field dimmer material of the connector.

[0057] Another aspect of the invention relates to a method of manufacturing a connection device as defined above, the method comprising, in this order:

[0058] obtaining a coaxial structure cable comprising a conductive core surrounded successively by a first semi-conductive layer, an insulating layer and a second semi-conductive layer;

[0059] removing at least a portion of the second semiconducting layer from a portion of cable adjacent to one end of the cable;

[0060] connect the cable to an electrical connector;

[0061] covering at least a portion of the insulating layer of the portion of cable above which the second semiconducting layer has been removed with a thickness of electric field dimming material;

[0062] covering the thickness of electric field dimmer material with a thickness of insulating material, the thickness of insulating material extending on either side onto the second semi-conducting layer of the cable, the thickness of insulating material partially covering the electrical connector.

[0063] In embodiments, the method may further comprise:

[0064] at least partially covering the thickness of insulating material with a thickness of semiconductor material, the thickness of semiconductor material being in contact with the second semiconducting layer of the cable on a portion of the cable located opposite the end of the cable from the portion of the cable on which the second semiconducting layer has been removed.

[0065] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0066] Other features and advantages of the invention will become apparent upon reading the description, which may be read in conjunction with the figures. These figures are presented for information purposes only and in no way limit the invention.

[0067] Figure 1a and Figure 1b show a coaxial structure cable from two different views.

[0068] Figure 2 represents an electrical connection device according to a first embodiment of the invention.

[0069] Figure 3 represents an electrical connection device according to a second embodiment of the invention.

[0070] Figure 4 represents an electrical connection device according to a third embodiment of the invention.

[0071] Figure 5 represents an electrical connection device according to a fourth embodiment of the invention.

[0072] Figure 6 represents a flowchart of a method of manufacturing an electrical connection device according to one embodiment of the invention.

[0073] Figure 7 represents equipotential lines obtained for a connection device according to the second embodiment.

[0074] Figure 8 shows an electrical connection device according to another embodiment of the invention.

[0075] Figure 9 represents an example of an electrical connection component according to one embodiment of the invention. DETAILED DESCRIPTION

[0076] Figure 2 represents an electrical connection device according to a first embodiment of the invention.

[0077] The electrical connection device of Figure 2 comprises a cable 10 and an electrical connector 30 connected to one end of the cable 10. The cable 10 has a coaxial structure like that of Figures 1 a and 1 b. In particular, the cable 10 comprises a conductive core 11 surrounded successively by a first semiconducting layer (inner semiconducting layer) 12, an insulating layer 13 and a second semiconducting layer (outer semiconducting layer) 14. The cable 10 also comprises a conductive connection layer 15 (for example a grounding braid), which can be extended or folded over the connection device as described later. The cable 10 may further comprise a mechanical and / or hermetic protection layer (sheath) not shown in Figure 2, which may cover the conductive connection layer 15.

[0078] In the embodiment shown in Figure 2, the outer semiconducting layer 14 of the cable 10 is removed over a portion of the cable 10 adjacent the end of the cable 10 connected to the electrical connector 30.

[0079] The area 40 interfacing between the portion of the cable 10 on which the outer semiconducting layer 14 has been removed and the remainder of the cable 10 (on which the outer semiconducting layer 14 is still present) is an area for strengthening the electric fields.

[0080] The connection device further comprises a thickness 21 of electric field dimmer material which covers the electric field reinforcement zone 40. The thickness 21 of electric field dimmer material thus continuously covers (i.e. without “holes”) a portion of the external semi-conductor layer 14 of the cable 10 (on the portion where it has not been removed) and a portion of the insulating layer 13 of the portion of the cable 10 on which the external semi-conductor layer 14 has been removed. This thickness 21 of electric field dimmer material has no point of contact with the connector 30.

[0081] The thickness 21 of electric field dimmer material, as well as its adjacent areas, are covered with a thickness 22 of insulating material. Thus, the thickness 22 of insulating material continuously covers the thickness 21 of electric field dimmer material, a portion of the insulating layer 13 of the cable 10, a portion of the connector 30, and a portion of the outer semiconducting layer 14 on the portion of the cable 10 for which this outer semiconducting layer 14 has not been removed.

[0082] In the example shown in Figure 2, the connector 30 comprises a conductive part 31 (called a “backshell” in English) and an insulating part 32 (called a “grommet” in English). The insulating part 32 of the electrical connector 30 may advantageously be sufficiently flexible (for example, in an elastomeric material) to grip, without leaving an air gap with the layer 13 of insulating material of the cable 10. The insulating part 32 of the connector 30 is in a material which may preferably have a relative permittivity of between 2 and 5 under the operating temperature conditions. The insulating part 32 of the electrical connector 30 may have an electrical conductivity of between 10' 16 S / m and 10' 13 S / m, preferably between 10' 15 S / m and 10' 14 S / m, and even more preferably around 10' 15S / m under the target operating temperature conditions (i.e. between -55°C and +260°C).

[0083] The thickness 22 of insulating material is in contact with both the conductive part 31 of the connector 30 and the insulating part 32 of the connector 30.

[0084] It is noted that the invention is not limited to the case where the connector 30 comprises a conductive part 31 and an insulating part 32. For example, the invention can be used in the case where the connector 30 does not comprise an insulating part 32. In this case, the thickness 22 can be housed in abutment against the conductive part 31, or even housed under the conductive part 31, as shown in Figure 8, etc.

[0085] Once the outer semiconductor layer 14 has been removed from a portion of the cable 10, this portion of the cable 10 is no longer suitable for withstanding partial discharge phenomena. The thickness 21 of electric field dimmer material and the thickness 22 of insulating material thus make it possible to restore to the cable 10 the properties necessary to withstand such phenomena.

[0086] The thickness 21 of electric field dimmer material and / or the thickness 22 of insulating material may be, for example, in the form of mastic, tape, varnish, glue, sheath, overmolded elastomer, or a combination thereof. In embodiments, the thickness 21 of electric field dimmer material and / or the thickness 22 of insulating material may be manufactured using a 3D printing technique. They may also have implementation properties such as adhesive, shrinkable, amalgamating, injectable or other. It is noted that the thickness 21 of electric field dimmer material and / or the thickness 22 of insulating material may comprise several layers of material, for example several layers of varnish or tape. It is noted that the thickness 21 of electric field dimmer material and the thickness 22 of insulating material may be assembled as shown in Figure 9 to form a single component before implementation on the cable. The component may further comprise a thickness of semiconducting material (similar to the thickness of semiconducting material 23 of Figures 3 and 5) covering the thickness 22 of insulating material.

[0087] Such a component can subsequently be deposited in a single operation on the cable 10 or in a conventional electrical connector comprising a conductive part 30.

[0088] In the example of Figure 2, the external semiconducting layer 14 of the cable 10 with coaxial structure is entirely removed on a portion adjacent to the electrical connector 30. This adjacent portion may, in certain embodiments, have a length of between 10 mm and 120 mm. The thickness 21 of electric field dimmer material may, for example, cover a length of insulating layer 13 of the cable 10 (on the portion of the cable on which the external semiconducting layer 14 has been removed) of between 5 mm and 60 mm (and of course, less than the length of the portion of cable 10 on which the external semiconducting layer 14 has been removed). This thickness 21 of electric field dimmer material may furthermore overhang the external semiconducting layer 14 over a distance of at least 5 mm.

[0089] The thickness 21 of electric field dimmer material may be composed of a silicone or other material, the temperature resistance of which is preferably between -55°C and +200°C and preferably between -55°C and +260°C and even more preferably between -65°C and +290°C.

[0090] The thickness 21 of electric field dimmer material can advantageously be in a material with high dielectric permittivity, for example a material having a relative permittivity greater than 10, and preferably greater than 15.

[0091] Further, the thickness 21 of electric field dimmer material may be in a material having an electrical conductivity of between 10' 5 S / m and 10' 16 S / m (particularly under the target operating temperature conditions, i.e. between -55°C and +260°C).

[0092] The thickness 21 of electric field dimmer material may have a thickness of between 0.1 mm and 4 mm, and preferably close to 1 mm (for example between 0.8 mm and 1.2 mm).

[0093] Also, the thickness 21 of electric field dimmer material may advantageously be sufficiently flexible so that the portion of the cable covered by the thickness of electric field dimmer material can be bent and withstand deformations associated with future use.

[0094] Finally, the thickness 21 of electric field dimmer material can advantageously be sufficiently flexible and amalgamating to prevent any appearance of air vacuoles encapsulated between the insulating material 13, the external semi-conducting layer 14 and the thickness of the electric field dimmer material 21.

[0095] In the example of Figure 2, the thickness 22 of insulating material is placed on the thickness 21 of electric field dimmer material, on the end of the insulating part 32 of the connector 30 connected to the cable 10 and on a part of the external semi-conducting layer 14 of the cable 10 (on the portion of cable 10 on which the external semi-conducting layer 14 has not been removed).

[0096] The thickness 22 of insulating material may be in a material having a temperature resistance similar to that of the material of the thickness 21 of electric field dimmer material.

[0097] Such a material may be, for example, an elastomer (e.g., silicones, XLPE, EPM, EPDM, EPR) or a heat-shrinkable material that meets target temperature ranges.

[0098] The thickness 22 of insulating material may for example be in a material having a relative permittivity of between 1 and 5, and preferably between 2 and 3. Furthermore, the thickness 22 of insulating material may be in a material having an electrical conductivity of less than 10' 15 S / m.

[0099] The thickness 22 of insulating material may have a thickness of between 0.1 mm and 4 mm, and preferably between 2 mm and 3 mm.

[0100] The thickness 21 of electric field dimmer material and the thickness 22 of insulating material advantageously allow the layer of insulating material 13 of the cable 10 to withstand the stresses of electric fields and partial discharges, despite the fact that the external semi-conductor layer 14 has been removed.

[0101] The thickness 22 of insulating material and the conductive part 31 of the connector 30 may be covered with a conductive connection layer 15 extending over the portion of the cable 10 on which the external semi-conductive layer 14 has not been removed.

[0102] This conductive connection layer 15 may be the conductive connection layer 15 of the cable 10. For example, as detailed below with reference to Figure 6, during the preparation of the electrical connection device according to the invention, the conductive connection layer 15 of the cable 10 may be “turned up” to remove the outer semiconducting layer 14 on one end of the cable 10. Then, the thickness 21 of electric field dimmer material and the thickness 22 of insulating material may be deposited. Finally, the conductive connection layer 15, which had been “turned up”, may be “raised” on the assembly thus formed. This conductive connection layer 15 covers the thickness 22 of insulating material, and is in contact with the outer semiconducting layer 14 of the cable 10 and the conductive part 31 of the connector 30 (to put these components at the same potential).

[0103] In other embodiments, it is possible to cover the assembly thus formed with a new conductive connection layer, the new conductive connection layer being in contact with the remaining conductive connection layer 15 of the cable 10 (on the portion of cable on which the external semi-conductive layer 14 has not been removed), so as to form a conductive connection layer without interruption of electrical continuity over the entire cable and the electrical connection device.

[0104] Furthermore, the conductive connection layer 15 can be surmounted by a clamping collar (not shown) at the level of the conductive part 31 of the connector 30, to hold the assembly.

[0105] Figure 3 represents an electrical connection device according to a second embodiment of the invention.

[0106] All references in Figure 3 that are identical to those in Figure 2 correspond to the same components, and the above description of these components applies similarly to this second embodiment.

[0107] Compared to the embodiment of Figure 2, the electrical connection device of Figure 3 further comprises a thickness 23 of semiconducting material, located between the thickness 22 of insulating material and the conductive connection layer 15. Thus, the thickness 23 of semiconducting material covers the thickness 22 of insulating material up to the separation zone of the conductive connection layer 15 and is in contact with the external semiconducting layer 14 of the cable (on the portion on which the external semiconducting layer 14 has not been removed).

[0108] The thickness 23 of semiconductor material advantageously improves protection against partial discharges and corona discharges. The thickness 23 of semiconductor material thus makes it possible to reduce the thickness of the thickness 22 of insulating material compared to the first embodiment, while still making it possible to limit the appearance of areas of reinforcement of the electric fields. Such a reduction in the thickness 22 of insulating material advantageously allows use in systems having strong mass and space constraints.

[0109] The thickness 23 of semiconductor material may be, for example, in a material having an electrical conductivity of between 10' 4 S / m and 1 S / m. Furthermore, the thickness 23 of semiconductor material may have a thickness of between 0.01 mm and 2 mm, and preferably between 0.5 mm and 1 mm.

[0110] The thickness 23 of semiconductor material may be, for example, in an insulating material comprising carbon black, carbon nanotubes or metal oxides.

[0111] The thickness 23 of semiconductor material may be, for example, in the form of mastic, tape, varnish, glue, sheath, overmolded elastomer, or a combination thereof. It may also have processing properties such as adhesive, shrinkable, amalgamating, injectable, or other. It is noted that the thickness 23 of semiconductor material may comprise several layers of material, for example several layers of varnish or tape.

[0112] Figure 7 represents equipotential lines obtained for a connection device according to the second embodiment. Figure 7 was obtained by electrokinetic simulation of the connection device of Figure 3.

[0113] The electrical potentials are decreasing from the inside of the connection device (the central area where the cable 10 is located) towards the outside of the connection device.

[0114] Figure 7 shows, at the level of zone 70, that the equipotential lines are sufficiently separated from each other, which means that the electric potential moves away from the triple point 40, which means that this triple point zone 40 is less constrained due to the presence of the thicknesses 21, 22 and 23. This Figure also shows the interest of the thickness 21 of field dimmer material which lets part of the electric field lines pass.

[0115] Figure 4 represents an electrical connection device according to a third embodiment of the invention.

[0116] In this third embodiment, the main difference with the first embodiment shown in Figure 2 is that the external semi-conducting layer 14 of the cable 10 is no longer removed over an entire portion adjacent to the connector 30, but only over a window 14a not adjacent to the connector 30. The window 14a over which the external semi-conducting layer 14 of the cable 10 is removed may for example have a length of between 8 mm and 30 mm.

[0117] Removing the outer semiconducting layer 14 from the cable 10 is not easy to implement. In practice, the outer semiconducting layer 14 must be scraped off, while taking care not to damage the layer of insulating material 13. The embodiment of Figure 4 (and that of Figure 5) makes it possible to remove the outer semiconducting layer 14 from the cable 10 over a short length compared to the previous embodiments, while limiting the appearance of areas of reinforcement of the electric fields.

[0118] Thus, in the embodiment shown in Figure 4, the outer semiconducting layer 14 of the cable 10 is removed over a window 14a (as well as over the end of the cable 10 connected to the connector 30). The thickness 21 of field-dimmer material at least partially covers (in the example of Figure 4, by half) the layer of insulating material 13 of the cable 10 at the window 14a, and overflows onto the outer semiconducting layer 14 of the second portion of the cable 10. For example, the thickness 21 of electric field-dimmer material may overflow onto the outer semiconducting layer 14 over a distance of at least 3 mm. The portion of the layer of insulating material 13 not covered by the thickness of electric field-dimmer material 21 is covered by the thickness 22 of insulating material.The thickness 22 of insulating material extends over the external semi-conducting layer 14 of the first portion of cable (end side of cable 10) and covers the thickness 21 of electric field dimmer material.

[0119] It is noted that the thickness 21 of material can completely cover the layer of insulating material 13 of the cable 10 at the window 14a, and overflow on either side onto the external semi-conductor layer 14. For example, the thickness 21 of electric field dimmer material can overflow on either side onto the external semi-conductor layer 14 over distances of at least 3 mm.

[0120] As mentioned above, this embodiment has an advantage in terms of implementation compared to that shown in Figure 2. It also has a lower risk of vacuole (trapping of air bubbles during the deposition of the thickness 21 of electric field dimmer material). It has overall the same performance as the embodiment shown in Figure 2 for limiting partial discharges, and it is slightly less efficient in limiting the strengthening of electric fields in triple point areas.

[0121] Figure 5 represents an electrical connection device according to a fourth embodiment of the invention.

[0122] In this fourth embodiment, the main difference with the second embodiment shown in Figure 3 is that the external semi-conducting layer 14 of the cable 10 is no longer removed over an entire portion adjacent to the connector 30, but only over a window 14a not adjacent to the connector 30, in a similar manner to the third embodiment described with reference to Figure 4.

[0123] Figure 6 represents a flowchart of a method of manufacturing an electrical connection device according to one embodiment of the invention.

[0124] In a first step 610, the cable 10 is prepared to be connected to the connector 30. In particular, the protective layer 16 is removed, the conductive connection layer 15 (for example a grounding braid) is folded back along the cable 10 in an opposite direction relative to the end of the cable intended to be connected to the connector 30, and the outer semiconducting layer 14 is removed (for example by scraping or peeling or by any other method) on a complete portion or on a window 14a, as mentioned above, and on the end intended to be connected to the connector 30. In the remainder of the description of Figure 6, it is considered that the outer semiconducting layer 14 is removed on a complete portion, but similar steps can be implemented for embodiments where the outer semiconducting layer 14 is removed only on a window 14a.

[0125] In an optional step 620, a first thickness of semiconductor material may be deposited around the junction between the portion of the cable on which the external semiconductor layer 14 is still present and the portion of the cable on which the external semiconductor layer 14 has been removed. This first thickness of semiconductor material makes it possible to reduce any roughness that may be present at the junction between the portion of the cable on which the external semiconductor layer 14 is still present and the portion of the cable on which the external semiconductor layer 14 has been removed. outer conductive layer 14 has been removed. This first thickness of semiconductor material is advantageously deposited so as to limit as much as possible the areas of air trapped between the cable and the first thickness of semiconductor material as well as the potential peak effects (for example by applying pressure, for example by mechanical compression or by vacuum). The first thickness of semiconductor material therefore covers a part of the cable portion 10 for which the outer semiconductor layer 14 has been removed and a part of the cable portion 10 for which the outer semiconductor layer 14 has not been removed.

[0126] During a step 630, the thickness 21 of field dimmer material is deposited:

[0127] - either, when step 620 is not implemented, around the junction between the portion of the cable on which the external semi-conductor layer 14 is still present and the portion of the cable on which the external semi-conductor layer 14 has been removed;

[0128] - either, when step 620 is implemented, so as to cover the first thickness of semi-conductor material of step 620, overflowing onto the layer 13 of insulating material of the portion of the cable on which the external semi-conductor layer 14 has been removed and onto the external semi-conductor layer 14 of the portion of the cable on which the external semi-conductor layer 14 has not been removed.

[0129] During a step 640, the thickness 22 of insulating material is deposited so as to cover the thickness 21 of field dimmer material by overflowing onto the external semi-conductor layer 14 of the portion of the cable on which the external semi-conductor layer 14 has not been removed to be in contact with this external semi-conductor layer 14. The thickness 22 of insulating material is further deposited so as to partially cover the connector 30, as described previously.

[0130] During an optional step 650 (implemented in particular for the embodiments of Figures 3 and 5), the thickness 23 of semiconducting material is deposited so as to at least partially cover the thickness 22 of insulating material and to be in contact with the external semiconducting layer 14 of the portion of the cable on which the external semiconducting layer 14 has not been removed.

[0131] As mentioned previously, the deposition of the thickness 23 of semiconductor material is optional. If the thickness 22 of insulating material has a sufficiently large thickness and the conductive connection layer 15 is applied in such a way as not to leave too large an air space, this thickness 23 of semiconductor material does not significantly increase the performance of the electrical connection device.

[0132] Finally, during a step 660, the conductive connection layer 15 of the cable 10 is reassembled on the “cable 10 - connector 30 - thickness of insulating material 22 - thickness of semi-conductor material 23” assembly. To improve the performance of the electrical connection device, this conductive connection layer 15 is preferably produced in such a way as to limit as much as possible the areas of air trapped between the conductive layer 15 and the components that it covers.

[0133] Of course, other implementations are possible, in particular to form the conductive connection layer of the electrical connection device, as mentioned above.

[0134] In other embodiments, at least some of the thicknesses 21, 22 and 23 may be directly integrated into the connector 30. A cable 10 at the end of which the outer semiconducting layer 14 has been removed may then be connected to this connector. In particular, the connector may comprise the components 21, 22, 23 (in certain embodiments), 31 and 32 of Figures 2 and 3. The cable may be connected to the connector by insertion, and the thickness 21 of field dimmer material may comprise a projection for receiving a portion of the outer semiconducting layer 14 located at the junction with the portion of the cable 10 on which the outer semiconducting layer 14 has been removed. Once the cable 10 has been inserted into the connector, the assembly thus obtained is according to Figures 2 and 3.

[0135] Integrating the thicknesses 21, 22 and 23 directly into the connector 30 makes it possible to reduce the length of the cable end 10 on which the external semi-conducting layer 14 must be removed to be connected to the connector 30. In addition, the thicknesses 21, 22, 23, when integrated into the connector 30, are better protected from external mechanical or environmental aggressions.

[0136] In some embodiments, the thickness 21 of electric field dimmer material is in a material that reacts non-linearly to the electric field. Such a material has an electrical resistivity or conductivity that varies depending on the value of the electric field it experiences. This allows the electric field to be further dimmer, and thus the stress peak to be reduced with a material that is more conductive. Thus, the electric field and potential crossing are also reduced thanks to the permittivity of the material.

[0137] For example, the material of thickness 21 of electric field dimmer material can have an electrical conductivity CT(E) depending on the electric field E according to an exponential function: <J(E) = <70expftzE)

[0138] with a0 the initial electrical conductivity of the material without the presence of an electric field and has a constant which depends on the material.

[0139] According to another example, the material of the thickness 21 of electric field dimmer material can have an electrical conductivity CT(E) such that:

[0140] with E the electric field value from which the electrical conductivity is no longer linear, and has a non-linearity coefficient which is obtained experimentally. This second form of electrical conductivity has a faster growth than the first. It can be chosen in particular in the case where strong overvoltages are expected.

[0141] Of course, the present invention is not limited to the embodiments described above as examples. It extends to other variants. It is noted that, if the present invention makes it possible to transport electrical power under high electrical voltages in the aeronautical field, it can also be used in other fields, in particular railway, maritime or land. It is understood that the dimensions of a connection device or a connection component according to the invention can be adapted (in particular, increased or reduced) depending on the applications envisaged.

Claims

CLAIMS

1. Electrical connection device comprising a cable (10) and an electrical connector (30) connected to one end of the cable, wherein the cable is a coaxial structure cable comprising a conductive core (11) surrounded successively by a first semi-conductive layer (12), an insulating layer (13) and a second semiconductor layer (14), wherein the cable (10) comprises a first cable portion and a second cable portion, wherein the first cable portion is a portion adjacent to said end on which at least a part of the second semiconductor layer is absent, the device comprising: - a thickness of electric field dimmer material (21) covering at least a portion of the insulating layer (13) of said first cable portion (10) and extending over a portion of the second semi-conductor layer (14) of said second cable portion, said thickness of electric field dimmer material (21) having no point of contact with said electrical connector (30), - a thickness of insulating material (22) covering the thickness of electric field dimmer material (21) and making contact with the second semiconductor layer (14) of said second cable portion (10) and with said electrical connector (30), wherein the thickness of insulating material (22) is covered with a conductive connection layer (15) extending over the second semi-conductive layer (14) of said second cable portion (10) and over at least a portion of the electrical connector (30).

2. Device according to claim 1, wherein the thickness of insulating material (22) is covered with a thickness of semiconducting material (23) in contact with the second semiconducting layer (14) of said second cable portion (10), the thickness of semiconducting material (23) being located between the thickness of insulating material (22) and the connecting conductive layer (15), wherein the thickness of semiconducting material (23) covers the thickness of insulating material (22) and overflows onto the second semiconducting layer (14) of said second cable portion (10) and extends to a conductive part (31) of the connector (30), in which the conductive connection layer (15) overflows onto the second semi-conductive layer (14) of said second cable portion (10) and onto the conductive part (31) of the electrical connector (30).

3. Device according to one of the preceding claims, wherein the first cable portion (10) comprises a first part on which the second semiconductor layer (14) is present, and a second part on which the second semiconductor layer (14) is absent, wherein the thickness of electric field dimmer material (21) at least partially covers the second part of the first cable portion (10), the thickness of electric field dimmer material (21) further extending onto the first part of the first cable portion (10).

4. Device according to one of the preceding claims, in which the thickness of electric field dimmer material (21) is in: - a material having a relative permittivity greater than or equal to 10; - a material with controlled electrical conductivity; - a semiconductor material; and / or - a material having an electrical conductivity dependent on an electric field.

5. An electrical connector for connection to a cable end (10), the connector comprising a conductive portion (31), the connector further comprising a thickness of electric field dimmer material (21) and a thickness of insulating material (22), wherein the thickness of insulating material (22) is in contact with the conductive portion (31), wherein the thickness of insulating material (22) completely covers the thickness of electric field dimmer material (21), said thickness of electric field dimmer material (21) having no point of contact with the conductive portion (31), wherein the connector comprises a recess for receiving said cable end (10), the recess passing through the thickness of insulating material (22) and the thickness of electric field dimmer material (21),wherein said thickness of electric field dimmer material (21) comprises a projection for receiving an outer layer of the cable, wherein the thickness of insulating material (22) is covered with a conductive connection layer (15) extending over the conductive part (31), the conductive connection layer (15) being such that, when the cable (10) is connected to the connector, the conductive connection layer extends over the outer layer of the cable.

6. Kit comprising a connector according to claim 8 and a cable (10) with a coaxial structure comprising a conductive core (11) surrounded successively by a first semiconducting layer (12), an insulating layer (13) and a second semiconducting layer (14), wherein the cable (10) comprises a first cable portion and a second cable portion, wherein the first cable portion is a portion adjacent to said end on which the second semiconducting layer (14) is absent, wherein, when the cable (10) is connected to the connector, the second semiconducting layer (14) is inside the projection of the thickness of electric field dimmer material (21) of the connector.

7. A method of manufacturing a device according to one of claims 1 to 4, the method comprising, in this order: - obtaining a cable with a coaxial structure comprising a conductive core surrounded successively by a first semi-conductive layer, an insulating layer and a second semi-conductive layer; - removing (610) at least a portion of the second semiconducting layer from a portion of cable adjacent to one end of the cable; - connect the cable to an electrical connector; - covering (630) at least a portion of the insulating layer of the portion of cable above which the second semi-conducting layer has been removed with a thickness of electric field dimmer material; - covering (640) the thickness of electric field dimmer material with a thickness of insulating material, the thickness of insulating material extending on either side onto the second semi-conducting layer of the cable, the thickness of insulating material partially covering the electrical connector; - covering (660) the thickness of insulating material with a conductive connection layer extending over the second semi-conductive layer of the cable and over at least part of the electrical connector.

8. The method of claim 10, further comprising, before covering the thickness of insulating material of the conductive connection layer: - covering (650) at least partially the thickness of insulating material with a thickness of semiconducting material, the thickness of semiconducting material being in contact with the second semiconducting layer of the cable on a portion of the cable located opposite the end of the cable relative to the portion of the cable on which the second semiconducting layer has been removed; wherein the conductive connection layer covers the thickness of semiconducting material and overflows onto the second semiconducting layer of the cable and onto the conductive portion of the electrical connector.

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