Electrical protection system for an aircraft with superconducting fuse connection

Abstract

The invention relates to an electrical protection system with a superconducting fuse connection for an aircraft, for example a hydrogen-powered aircraft, for the electrical connection of an electrical circuit of the aircraft, the electrical protection system comprising an element, called a fuse element, made of a material exhibiting superconducting properties in a first state, called the superconducting state, and exhibiting non-superconducting properties in a second state, called the normal state, the transition from the superconducting state to the normal state releasing a transition energy, the protection system further comprising a device, called a safety device, designed to break the electrical connection when the fuse element changes from the superconducting state to the normal state.

Description

Technical Field

[0001] This invention relates to an electrical protection system for electrical connections of circuits in aircraft (particularly hydrogen-powered aircraft). Background Technology

[0002] To reduce the carbon footprint caused by aviation, the applicant has developed a design for hydrogen-powered aircraft with its own motor. To enhance the competitiveness of this propulsion type, the applicant has developed specific equipment, particularly a propulsion chain incorporating a superconducting motor. Such a chain enables the conduction of currents with higher intensity, and it has then proven necessary to reliably manage such high nominal operating currents, as well as even higher fault currents.

[0003] The purpose of this invention is to improve the current situation. Summary of the Invention

[0004] To this end, an electrical protection system is proposed for the electrical connections of circuits in aircraft, such as those powered by hydrogen and / or including superconducting motors. This electrical protection system includes an element called a fuse element, which is made of a material that exhibits superconducting properties in a first state called a superconducting state and non-superconducting properties in a second state called a normal state. The transition from the superconducting state to the normal state releases transition energy. The protection system also includes a device called a safety device, which is designed to disconnect the electrical connection when the fuse element changes from the superconducting state to the normal state.

[0005] Therefore, in the event of a short circuit, the current suddenly increases, triggering the fuse element to switch from a superconducting state to a normal state, and the safety device disconnects the electrical connection, which effectively protects the circuit.

[0006] According to another aspect, the system includes a heat exchanger thermally connected to a fuse element, which is designed to keep the fuse element in a superconducting state.

[0007] On the other hand, a safety device is a device used to absorb and transform energy.

[0008] According to another perspective, the device used to absorb the converted energy includes silicon dioxide.

[0009] On the other hand, silica is designed to melt under the influence of energy conversion and then solidify by cooling.

[0010] According to another perspective, the device used to absorb the converted energy is in the form of a gel.

[0011] According to another perspective, the material of the fuse element is BSCCO and / or YBCO and / or MgB2 and / or REBCO.

[0012] According to another aspect, the protection system includes the aforementioned electrical connection.

[0013] Another subject of the invention is a circuit, such as a propulsion chain for an aircraft, which includes a superconducting motor, and the circuit includes a protection system as described above.

[0014] Another subject of the present invention is an aircraft comprising the circuitry described above. Attached Figure Description

[0015] Further features, details, and advantages will become apparent upon reading the following detailed description and by studying the accompanying drawings, in which:

[0016] Figure 1 This is a schematic diagram of the longitudinal section of the electrical protection system integrated into the electrical connection according to the present invention in normal operating mode.

[0017] Figure 2 yes Figure 1 A detailed schematic diagram of the system.

[0018] Figure 3 The diagram illustrates the variation of the current flowing through the electrical connection over time in the case of a short circuit, according to successive stages A, B, C, and D. Detailed Implementation

[0019] The examples and related conditions described in detail herein are primarily intended to help the reader understand the principles of the invention, and not to limit the scope of the invention to these specific examples and conditions. It will be understood that those skilled in the art will contemplate various arrangements, although these arrangements are not expressly described or represented herein, but which embody the principles of the invention and are included within its spirit and scope.

[0020] Furthermore, to facilitate understanding, the following description illustrates a relatively simplified implementation of the invention. As those skilled in the art will understand, other implementations of the invention can be more complex.

[0021] In some cases, examples of modifications to the invention may also be presented. This is done merely to aid understanding, and not to limit the scope of the invention or to impose any restrictions on it. These modifications are not exhaustive, and those skilled in the art can make other modifications while still remaining within the scope of the invention.

[0022] Furthermore, all statements below relating to the principles, aspects, and implementations of the invention, as well as specific examples thereof, are intended to cover both structural and functional equivalents of the invention, whether such structural and functional equivalents are currently known or will be developed in the future.

[0023] As can be seen from the figures, the subject of this invention is an electrical protection system 1 for an electrical connection 2. The electrical connection 2 forms part of a circuit 3 of an aircraft, such as a hydrogen-powered aircraft. The circuit 3 is, for example, the propulsion chain of the aircraft, comprising one or more superconducting devices, such as superconducting motors.

[0024] In the accompanying drawings, connection 2 includes: a first cable, referred to as power cable 4; a superconducting cable 5; and a protection system 1 disposed between cable 4 and cable 5. Power cable 4 is directly or indirectly connected to fuel cell 6. Superconducting cable 5 is directly or indirectly connected to propulsion unit 7.

[0025] As shown in the figure, the protection system 1 includes a fuse element 10. In the illustrated embodiment, the fuse element 10 is in the form of a superconducting strip or a superconducting link.

[0026] The fuse element 10 is made of a material that exhibits superconducting properties in a first state, known as the superconducting state, and non-superconducting properties in a second state, known as the normal state.

[0027] One of the known properties of superconductivity is that the resistance of a material is zero in the superconducting state, while it has a non-zero resistance in the normal state.

[0028] When a material is subjected to a temperature below the so-called critical temperature Tc and / or to a magnetic field corresponding to the critical current Ic, the material is in a superconducting state.

[0029] Under the influence of a temperature greater than or equal to the critical temperature Tc and / or a current greater than or equal to the critical current Ic, a material undergoes a transition from a superconducting state to a normal state, releasing energy known as transition energy. This transition energy can be released in the form of an electric arc. More precisely, during the transition from the superconducting state to the normal state, loss of superconductivity occurs. The material begins to heat up and then melts. Finally, an electric arc is generated when the molten material fractures.

[0030] Preferably, a superconducting material with a high critical temperature is selected.

[0031] Superconducting materials are, for example, BSCCO (a mixed oxide of bismuth, calcium, copper and strontium) and / or YBCO (a mixed oxide of barium, copper and yttrium) and / or MgB2 and / or ReBCO (a mixed oxide of barium, copper and rare earth elements).

[0032] In the case of ReBCO, for example, a strip with a width of a few millimeters is selected, for example, between 1 mm and 10 mm, or between 15 mm and 20 mm, or between 10 mm and 15 mm. The strip length is a few centimeters, for example, between 2 cm and 5 cm. The thickness is, for example, 100 nm. The critical current at the critical temperature Tc of 77 K is, for example, between 800 A and 1500 A, or for example, between 1000 A and 1200 A.

[0033] As can be seen from the figure, the protection system 1 also includes a safety device 11 for interrupting the electrical connection 2 during the transition of the fuse element 10 from the superconducting state to the normal state.

[0034] Safety device 11 is, for example, a device for absorbing transition energy. During the transition from the superconducting state to the normal state, energy, including the form of plasma arc, is absorbed by safety device 11.

[0035] According to one variation, the device 11 for absorbing the converted energy includes a material with high heat capacity, such as silicon dioxide, which is granular in the normal operating configuration of the electrical connection 2 (in... Figure 2 It is represented in the form of S). Under the influence of energy conversion, the silica particles melt and then solidify by cooling. Energy absorption allows the plasma arc to be cooled and extinguished, while also ensuring that it is confined without any leakage.

[0036] Alternatively or otherwise, the device for absorbing the converted energy is in the form of a gel.

[0037] Advantageously, housing 12 contains fuse element 10 and safety device 11. Within housing 12, a superconducting link connects power cable 4 to superconducting cable 5. Heat exchanger 13 connects fuse 10 (in...) Figure 1 The left side of the middle section is electrically connected to the superconducting cable 5.

[0038] As can be seen in the figure, the protection system 1 includes a heat exchanger 13. The heat exchanger 13 is thermally connected to the housing 12, a portion of the power supply cable 4, and / or a portion of the superconducting cable 5.

[0039] In the accompanying drawings, the heat exchanger 13 is fixed to and preferably in contact with the housing 12. Preferably, the housing 12 is made of a material with very high thermal conductivity, which ensures good heat transfer between the heat exchanger 13 and the fuse element 10. For example, it is a non-metallic material that exhibits a fairly low degassing rate in a vacuum environment and is thermally conductive and electrically insulating, such as a ceramic, for example, alumina.

[0040] In the figure, the heat exchanger 13 is fixed to a portion of the power supply cable 4, and preferably in contact with a portion of the power supply cable 4.

[0041] In the figure, the heat exchanger 13 is fixed to a portion of the superconducting cable 5, preferably in contact with a portion of the superconducting cable 5.

[0042] Heat exchanger 13 ensures that the superconducting cable 5 and fuse element 10 are maintained at a low temperature. A low temperature is understood to mean a temperature below the critical temperature of the cable 5 and fuse element 10. If the cable 5 and the fuse do not have the same critical temperature, the protection system 1 is designed to maintain the temperature below the lower of the two critical temperatures. Heat exchanger 13 is also designed to maintain the superconducting link of fuse element 10 at a low temperature between its two ends, preferably between 2 K and 5 K in the superconducting link. Figure 1 The temperature gradient (denoted as T1) is the temperature between temperatures denoted as T2. Cable 4 extends towards the end of fuel cell 6. At ambient temperature, such as 300 K.

[0043] It should be noted that the protection system 1 also includes an electrically and thermally insulating insulator, for example made of ceramic, to insulate the input and output of the fuse element 10. The insulator also allows for optimized heat transfer between the fuse element 10 and the heat exchanger 13.

[0044] The operation of protection system 1, which can be seen from the above description, will now be described.

[0045] In normal operating mode, in electrical connection 2, the power supply current (Ia) flows from fuel cell 6 through power supply cable 4, through the superconducting link of protection system 1, and then through superconducting cable 5 to reach propulsion unit 7.

[0046] In the case of a short circuit, schematically, during stage A, the current becomes greater than the critical current of superconducting link 10, causing the superconducting link to disconnect and the material to change from a superconducting state to a normal state. During stage B, the transition from the superconducting state to the normal state generates transition energy, specifically in the form of an electric arc, the magnitude of which depends on the power of the plasma arc and the induced energy stored in the circuit. During stage C, at a temperature of, for example, approximately 20,000 K, the silica particles melt, allowing the released heat to be absorbed. The plasma arc is cooled and then extinguished. During stage D, the silica solidifies, completely blocking the current. Electrical connection 2 is disconnected and electrical isolation is ensured.

[0047] As shown in the figure, during the short circuit, the current increases rapidly between stage A and stage D, and then decreases. The transition (superconductor loss of superconductivity) has a current-limiting effect. As the resistance increases during the transition, the current decreases. This is called the confined short-circuit current (denoted as ILsc for the "confined short-circuit" current). At the end of stage D, the current is zero. Figure 3 The duration between phases A and D, indicated by the double-headed arrow, is in milliseconds.

[0048] As explained, in the event of a short circuit, the superconducting link ensures a rapid transition between the superconducting state and the normal state. During the transition, the superconducting link heats up and melts, potentially generating a plasma arc. Due to the high current density flowing through electrical connection 2, the energy required to disconnect the superconducting link is low, ensuring that protection system 1 reacts quickly in the event of a short circuit. In other words, device 1 has very little inertia, making protection system 1 highly effective.

[0049] Furthermore, under normal conditions, the material has a slow current propagation speed due to its non-zero resistance, which ensures that the fault remains localized and does not propagate.

[0050] Because of protection system 1, the electrical connection can be disconnected in less than 10 ms, while extinguishing any possible arcing.

[0051] As can be seen from the above description, the present invention has the following advantages:

[0052] - Respond quickly,

[0053] - Electrical isolation,

[0054] - Under normal operating conditions, energy loss is very low even at high current.

[0055] - Due to the integrated heat exchanger that ensures active cooling, heat loss in heat distribution and conduction is very low at low temperatures.

[0056] - Two-way operation

[0057] - Confines the plasma arc within the fuse element's enclosure without leakage; effectively absorbs the plasma arc (especially on high-induction lines) when the superconducting link breaks. It should be noted that short circuits on high-induction lines can generate even higher-energy arc plasma when the superconducting connection breaks. Since silica allows for better and more uniform thermal termination, its use is particularly useful in such cases of short circuits on high-induction lines.

[0058] - It is compact and lightweight because it integrates heat exchangers and power cables that serve as both mechanical and electrical interfaces.

[0059] Modifications and improvements to the above-described implementation of the present invention can be conceived by those skilled in the art.

[0060] The above description is illustrative by way of example and not restrictive. Therefore, the scope of the invention is limited only by the scope of the appended claims.

Claims

1. An electrical protection system for electrical connections of circuits of an aircraft, such as an aircraft powered by hydrogen and / or including a superconducting motor, the electrical protection system comprising an element called a fuse element (10) made of a material exhibiting superconducting properties in a first state called a superconducting state and non-superconducting properties in a second state called a normal state, the transition from the superconducting state to the normal state releasing transition energy, the protection system (1) further comprising a device called a safety device (11) designed to disconnect the electrical connection (2) when the fuse element (10) changes from the superconducting state to the normal state.

2. The protection system according to claim 1, comprising a heat exchanger (13) thermally connected to the fuse element (10), designed to hold the fuse element (10) in the superconducting state.

3. The protection system according to any one of the preceding claims, wherein, The safety device (11) is a device for absorbing the converted energy.

4. The protection system according to the preceding claims, wherein, The device for absorbing the converted energy includes silicon dioxide.

5. The protection system according to the preceding claims, wherein, The silica is designed to melt under the influence of the transformation energy and then solidify by cooling.

6. The protection system according to any one of claims 3 to 5, wherein, The device for absorbing the converted energy is in the form of a gel.

7. The protection system according to any one of the preceding claims, wherein, The material of the fuse element is BSCCO and / or YBCO and / or MgB2 and / or ReBCO.

8. The protection system according to any one of the preceding claims, including the electrical connection (2).

9. A circuit (3), such as a propulsion chain for an aircraft, the propulsion chain comprising a superconducting motor, the circuit comprising the protection system according to claim 8.

10. An aircraft comprising the circuitry of claim 9.

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