ELECTRICAL WIRING HARNESS WITH ELECTROMAGNETIC PROTECTION SYSTEM AND ARC DETECTION SYSTEM AND METHOD FOR MANUFACTURING SUCH A WIRING HARNESS

Description

[0001] The present application relates to an electrical harness comprising an electromagnetic protection system and an electric arc detection system as well as to a method of manufacturing such an electrical harness.

[0002] According to an embodiment visible on the figure 1 , an electrical harness 10 comprises at least one electrical connection 12 comprising at least one conductive element as well as an electromagnetic protection system 14 comprising a tubular casing 16, surrounding the electrical connection 12, obtained by braiding spindles 16.1 of metal strands 16.2. According to one configuration, the tubular casing 16 comprises sixteen spindles 16.1 of five metal strands 16.2 each.

[0003] Document FR3101195 describes an electrical connection equipped with an electric arc detection system. According to this document, the electrical connection comprises an electrical conductor surrounded by an insulating sheath. In addition, the electric arc detection system comprises a textile sheet, composed of a plurality of optical fibers and transparent weft threads (allowing light to pass through), wound around the insulating sheath, a photo-detection component configured to receive a light beam guided by the optical fibers and emit an electrical signal according to the received light beam as well as a control configured to control the circuit breaker according to the electrical signal emitted by the photo-detection component.Thus, in the event of an electric arc appearing, the luminous flux generated by the latter is captured by the optical fibers which transmit it to the photo-detection component which generates an electrical signal sent to a circuit opening device (in English "circuit breaker").

[0004] Integrating an electromagnetic protection system and an electric arc detection system on the same electrical harness is not optimal because it requires two coaxial tubular enclosures, one for each system, which leads to a significant increase in the mass of the electrical harness.

[0005] Another relevant state of the art document is CN 112 578 226 A.

[0006] The present invention aims to remedy all or part of the drawbacks of the prior art.

[0007] To this end, the invention relates to an electrical harness comprising: at least one electrical connection, an electromagnetic protection system comprising a tubular envelope obtained by braiding spindles of strands and positioned around the electrical connection, at least 80% of the strands of the spindles being metallic, an electric arc detection system comprising at least one optical fiber positioned near the electrical connection and at least one photo-detection component configured to receive a light beam guided by the optical fiber.

[0008] According to the invention, the tubular envelope comprises strands in the form of sections of optical fiber forming at least part of the electric arc detection system.

[0009] According to the invention, the strands in the form of sections of optical fiber have a diameter substantially identical to that of the metal strands.

[0010] According to the invention, the same tubular casing comprises metal strands forming at least part of the electromagnetic protection system as well as strands in the form of sections of optical fiber forming at least part of the electric arc detection system. This solution contributes to reducing the mass of an electrical harness integrating the electromagnetic protection and electric arc detection functions.

[0011] According to another characteristic, for at least half of the spindles of the tubular envelope, all the strands are metallic while for the other spindles of the tubular envelope, at least 75% of the strands are metallic.

[0012] According to one embodiment, the tubular envelope comprises sixteen spindles as well as four strands, each in the form of a section of optical fiber, regularly distributed around the electrical connection in four spindles.

[0013] According to another embodiment, the tubular envelope comprises sixteen spindles as well as eight strands, each in the form of a section of optical fiber, regularly distributed around the electrical connection in eight spindles.

[0014] According to another characteristic, each optical fiber is a single-mode or multi-mode optical fiber.

[0015] According to another feature, the optical fiber sections are connected in parallel.

[0016] According to another characteristic, each strand in the form of a section of optical fiber extends over the entire length of the tubular envelope and has at least one excess length at at least one end of the tubular envelope.

[0017] The invention also relates to a method for manufacturing an electrical harness according to one of the preceding characteristics. According to the invention, the tubular envelope is obtained by simultaneous overbraiding, on the electrical connection, of metal strands forming at least part of the electromagnetic protection system as well as strands in the form of sections of optical fiber forming at least part of the electric arc detection system.

[0018] The invention also relates to an aircraft comprising at least one electrical harness according to one of the preceding characteristics.

[0019] Other characteristics and advantages will emerge from the description of the invention which follows, a description given by way of example only, with reference to the appended drawings, among which: There figure 1 is a schematic representation of an electrical harness illustrating an embodiment of the prior art, The figure 2 is a side view of an aircraft, The figure 3 is a side view of an electrical harness illustrating one embodiment of the invention, The figure 4 is a schematic representation of an electrical harness illustrating a first embodiment of the invention, The figure 5 is a cross-section of the electrical harness visible on the figure 4 , and The figure 6 is a cross-section of an electrical harness illustrating another embodiment of the invention.

[0020] According to an embodiment visible on the figures 3 à 6 , an electrical harness 20 comprises at least one electrical connection 22 comprising at least one conductive element as well as an electromagnetic protection system 24 surrounding the electrical connection 22.

[0021] This electromagnetic protection system 24 makes it possible to obtain shielding, around the electrical connection 22, configured to protect it from electromagnetic disturbances generated by external elements and to protect elements external to the electrical harness 20 from electromagnetic disturbances generated by the electrical connection 22.

[0022] The electrical connection 22 may comprise several conductive elements 22.1, as illustrated in the figures 5 et 6 , each comprising an insulating envelope such as a plastic sheath for example.

[0023] According to an application visible on the figure 2 , an aircraft 26 comprises an electrical installation 28 comprising at least one high-voltage electrical power source 28.1, at least one user equipment 28.2 and at least one electrical harness 20 connecting the high-voltage electrical power source 28.1 and the user equipment 28.2. According to one configuration, the high-voltage electrical power source provides a direct voltage of the order of + or - 270 Volts DC, or + or - 540 Volts DC. Of course, the invention is not limited to this application or to these voltages.

[0024] The electromagnetic protection system 24 comprises a tubular casing 30 obtained by braiding and positioned around the electrical connection. This tubular casing 30 comprises several spindles 30.1 each comprising several strands 32, 34. According to one embodiment, the tubular casing 30 comprises sixteen spindles 30.1 of five strands 32, 34 each. Of course, the invention is not limited to this number of spindles or strands for each spindle. In addition, the elementary diameter of each strand can vary in the same spindle or between two spindles. The majority of the strands 32 of the different spindles 30.1 are metallic to obtain the electromagnetic protection system 24. According to one embodiment, the metallic strands 32 are based on nickel-plated or tin-plated or silver-plated copper.

[0025] According to one configuration, the metal strands 32 have a diameter of the order of 150 to 250 µm. Whatever the configuration, to obtain the electromagnetic protection system 24, the metal strands 32 must cover at least 85% of the surface of the tubular casing 30. In addition, the tubular casing 30 must have at low frequency a linear resistance of the order of 5 mOhm / m and an inductance of the order of 2 nH.

[0026] To obtain these characteristics, at least 80% of the strands 32 of the gores 30.1, 30.1' of the tubular casing 30 are metallic. Preferably, at least 90% of the strands 32 are metallic. According to one distribution, one half or more of the gores 30.1 is made exclusively from metallic strands 32, the other gores 30.1' comprising at least 75% of metallic strands 32.

[0027] According to one arrangement, all the spindles 30.1 have the same number of strands 32, 34. Each spindle 30.1, 30.1' is in the form of a sheet of strands 32, 34 juxtaposed next to each other. Thus, each spindle 30.1, 30.1' comprises a first end strand 32, 34 as well as a second end strand 32, 34 as far apart as possible from the first end strand.

[0028] According to a first embodiment visible on the figures 4 et 5 , 75% of the 30.1 spindles are made exclusively from 32 metal strands, the other 30.1' spindles comprising at least 80% of 32 metal strands, i.e. four 32 metal strands out of five strands.

[0029] According to a second embodiment visible on the figure 6 , 50% of the 30.1 spindles are made exclusively from 32 metal strands, the other 30.1' spindles comprising at least 80% of 32 metal strands, i.e. four 32 metal strands out of five strands.

[0030] According to an embodiment visible on the figure 3 , the electrical harness 20 also comprises an electric arc detection system 36 comprising at least one optical fiber 36.1 positioned near the electrical connection 22, at least one photo-detection component 36.2 configured to receive a light beam guided by the optical fiber 36.1 and emit an electrical signal as a function of the received light beam as well as at least one control 36.3 configured to emit at least one control signal as a function of the electrical signal emitted by the photo-detection component 36.2. More precisely, the at least one optical fiber 36.1 is positioned at least partly around the electrical connection 22.

[0031] According to one configuration, the electric arc detection system 36 also comprises at least one circuit breaker positioned on the electrical connection 22, splitting it into upstream and downstream sections, configured to occupy a closed state in which it allows current to pass between the upstream and downstream sections of the electrical connection 22 as well as an open state in which it interrupts the flow of current between the upstream and downstream sections of the electrical connection 22 upon receipt of a control signal transmitted by the control 36.3. The electric arc detection system 36 is not limited to this electrical circuit opening function. Thus, it can provide an optical locking function at the time of ignition (function of securing the electrical connection in the event of disconnection by a maintenance operator) or any other function.

[0032] Each optical fiber 36.1 comprises at least one section forming a strand 34 of one of the spindles 30.1' of the tubular casing 30 of the electromagnetic protection system 24. According to one configuration, the same optical fiber 36.1 comprises several sections each forming a strand 34 of different spindles 30.1'. According to another configuration visible on the figure 4 , each optical fiber 36.1 comprises a single section forming a strand 34 of a spindle 30.1'.

[0033] According to these two configurations, all the non-metallic strands 34 are sections of optical fiber 36.1. Thus, the strands 32, 34 of the spindles 30.1, 30.1' of the tubular casing 30 are exclusively metallic or in the form of sections of optical fiber 36.1. Thus, according to the invention, the same tubular casing 30 comprises metallic strands 32 forming at least a part of the electromagnetic protection system 24 as well as strands 34 in the form of sections of optical fiber 36.1 forming at least a part of the electric arc detection system 36. This solution contributes to reducing the mass of an electrical harness 20 integrating the electromagnetic protection and electric arc detection functions. According to one embodiment, the strands 34 in the form of sections of optical fiber 36.1 are regularly distributed around the electrical connection 22.

[0034] According to a first embodiment visible on the figures 4 et 5 , the tubular casing 30 comprises four strands 34, each in the form of a section of optical fiber 36.1, regularly distributed around the electrical connection 22 in four spindles 30.1'. Thus, one spindle 30.1' out of four comprises a strand 34 in the form of a section of optical fiber 36.1. According to this first embodiment, each section of optical fiber 36.1 ensures the detection of electric arcs over an angular sector of the order of 90°.

[0035] According to a second embodiment visible on the figure 6 , the tubular envelope 30 comprises eight strands 34, each in the form of a section of optical fiber 36.1, regularly distributed around the electrical connection 22 in eight spindles 30.1. According to a first arrangement, one spindle 30.1' out of two comprises a strand 34 in the form of a section of optical fiber 36.1. According to a second arrangement visible on the figure 6 , the tubular casing 30 comprises several pairs of adjacent spindles 30.1' separated by two spindles 30.1 comprising exclusively metal strands 32. For each pair of adjacent spindles 30.1', the first and second end strands, the most spaced apart, are each in the form of a section of optical fiber 36.1, the other strands 32 of each pair of adjacent spindles 30.1' being metal. According to these two arrangements, the strands 34 in the form of sections of optical fiber 36.1 are regularly distributed around the electrical connection 22, each section of optical fiber 36.1 ensuring the detection of electric arcs over an angular sector of the order of 45°.

[0036] According to the first and second embodiments, half or less of the spindles 30.1, 30.1' each comprise at most one strand 34 in the form of a section of optical fiber.

[0037] The strands 34 in the form of sections of optical fiber 36.1 have a diameter substantially identical to that of the metal strands 32, of the order of 150 to 250 µm.

[0038] According to one configuration, each optical fiber is a standard multimode optical fiber, for example of diameter 50 / 125 or 62.5 / 125. According to another configuration, each optical fiber is a single-mode optical fiber, for example of diameter 9 / 125. Of course, the invention is not limited to these optical fiber diameters, but a multimode or single-mode optical fiber of different diameter could be used.

[0039] According to one embodiment, the optical fibers 36.1 are plastic optical fibers called POF (for Polymer Optical Fiber in English) and / or photonic crystal fibers called PCF (for Polymer Cladded Fiber). Whatever the embodiment, the optical fibers 36.1 are configured to operate at temperatures of the order of 150 to 180°C and have mechanical characteristics allowing braiding or overbraiding.

[0040] According to an embodiment visible on the figures 3 And 4 , the 36.1 optical fiber sections are connected in parallel.

[0041] When the optical fiber sections 36.1 are connected in parallel, the optical fiber sections 36.1 are connected by at least one ferrule 38 at each end of the tubular casing 30. For example, each ferrule 38 is used as a male contact intended to be inserted into a male connector and has a size 8.

[0042] Each strand 34 in the form of a section of optical fiber 36.1 extends over the entire length of the tubular casing 30, like the metal strands 32, and has at least one excess length at at least one end of the tubular casing 30. Thus, each ferrule 38 is spaced from the end of the tubular casing 30. This configuration makes it possible to simplify the connection of the sections of optical fiber to each other. According to one embodiment, each strand 34 in the form of a section of optical fiber 36.1 has an excess length at each end of the tubular casing 30.

[0043] The photo-detection component 36.2 and the control 36.3 of the electric arc detection system 36 are not further described because they may be identical to those of the prior art. According to one method of operation, the tubular envelope 30 is obtained by simultaneous over-braiding on the electrical connection 22 of metal strands 32 forming at least a part of the electromagnetic protection system 24 as well as of strands 34 in the form of sections of optical fiber 36.1 forming at least a part of the electric arc detection system 36 so as to obtain a single tubular envelope 30 surrounding the electrical connection 22.

[0044] For example, the overbraiding process includes: a step of winding metal strands 32 and strands 34 in the form of sections of optical fiber 36.1, a step of placing the coils on an overbraiding machine, a step of adjusting the tension springs of the overbraiding machine, a step of adjusting the braiding angle, a step of braiding the tubular envelope 30 around the electrical connection 22.

[0045] This solution ensures that the tubular casing 30 is in contact with the electrical connection 22 and has the smallest possible diameter and therefore mass. In addition, this solution makes it possible to obtain, at the end of the overbraiding process, a single tubular casing 30 integrating the electromagnetic protection system 24 and the electric arc detection system 36.

[0046] According to one embodiment, the electrical harness 20 may comprise a protective sheath inserted between the tubular casing 30 and the electrical connection 22, for example made of polytetrafluoroethylene (PTFE), to protect the electrical connection 22 during overbraiding and / or a mechanical protection 40 added to the tubular casing 30, such as a sheath obtained by overbraiding synthetic fibers, for example made of aramid.

Claims

1. Electrical harness (20) comprising: - at least one electrical connection (22), - an electromagnetic protection system (24) comprising a tubular jacket (30) obtained by braiding bundles (30.1, 30.1') of strands (32, 34) and positioned around the electrical connection (22), at least 80% of the strands (32) of the bundles (30.1, 30.1') being made of metal, - a system (36) for detecting electric arcs which comprises at least one optical fiber (36.1) positioned close to the electrical connection (22) and at least one photodetection component (36.2) configured to receive a light beam guided by the optical fiber (36.1), wherein the tubular jacket (30) comprising strands (34) in the form of segments of optical fiber (36.1) forming at least part of the system (36) for detecting electric arcs, and characterized in that the strands (34) in the form of segments of optical fiber (36.1) have a diameter that is substantially identical to that of the metal strands (32).

2. Electrical harness (20) as claimed in claim 1, wherein all the strands (32) are made of metal for at least half of the bundles (30.1) of the tubular jacket (30) while at least 75% of the strands (32) are made of metal for the other bundles (30.1') of the tubular jacket (30).

3. Electrical harness (20) as claimed in the preceding claim, wherein the tubular jacket (30) comprises sixteen bundles (30.1, 30.1') and four strands (34), each in the form of a segment of optical fiber (36.1), regularly distributed around the electrical connection (22) in four bundles (30.1').

4. Electrical harness (20) as claimed in claim 2, wherein the tubular jacket (30) comprises sixteen bundles (30.1, 30.1') and eight strands (34), each in the form of a segment of optical fiber (36.1), regularly distributed around the electrical connection (22) in eight bundles (30.1').

5. Electrical harness (20) as claimed in one of the preceding claims, wherein each optical fiber (36.1) is a single-mode or multi-mode optical fiber.

6. Electrical harness (20) as claimed in one of the preceding claims, wherein the segments of optical fiber (36.1) are connected in parallel.

7. Electrical harness (20) as claimed in one of the preceding claims, wherein each strand (34) in the form of a segment of optical fiber (36.1) extends over the entire length of the tubular jacket (30) and has at least one excess length at at least one end of the tubular jacket (30).

8. Process for manufacturing an electrical harness (20) as claimed in one of the preceding claims, wherein the tubular jacket (30) is obtained by simultaneously overbraiding, on the electrical connection (22), metal strands (32) forming at least part of the electromagnetic protection system (24) and strands (34) in the form of segments of optical fiber (36.1) forming at least part of the system (36) for detecting electric arcs.

9. Aircraft comprising at least one electrical harness (20) as claimed in one of claims 1 to 7.