Circuit equipped with two pyrotechnic switches, allowing electrical isolation of portion in event of short-circuit-type fault

Abstract

The invention relates to an electrical circuit (100) of an aircraft, comprising a power source (4) electrically connected to an electrical load (31) by an electrically conductive element (7) and a main electrical protection element (6), in which the electrical circuit (100) comprises: a first pyrotechnic switch (1) provided with at least one first igniter element (11) and at least one first mechanical cutoff element (12); and a second pyrotechnic switch (2) provided with at least one second igniter element (21) and at least one second mechanical cutoff element (22), the first igniter element (11) and the second igniter element (21) being respectively positioned in electrical parallel with the at least one main electrical protection element (6).

Description

Technical Field

[0001] The present invention relates to the field of circuits, and more particularly to a circuit for supplying at least one electrical load of an aircraft. Background Art

[0002] In the present disclosure, the term "aircraft" refers to a set of devices capable of navigating in the air, such as traditional aircraft also referred to by the acronym CTOL (conventional takeoff and landing), vertical takeoff and landing aircraft referred to by the acronym VTOL (vertical takeoff and landing), and short takeoff and landing aircraft referred to by the acronym STOL.

[0003] It is known that an aircraft includes electrical loads, that is, devices that consume electrical power during normal operation. For example, an electrical load may be an electric propulsion device including at least one electric motor.

[0004] The electric propulsion device is powered by a circuit providing a high-voltage direct current, for example greater than 800V.

[0005] It is known that a circuit includes at least one power source, at least one power distribution box, and at least one power distribution harness.

[0006] The power source corresponds to an electrical generator such as a battery.

[0007] The power distribution box includes at least one switching element, such as a contactor, allowing the power distribution harness to be switched on or off, and thus ultimately allowing the electric propulsion device.

[0008] The power distribution harness including at least one conductive element such as a cable transports electrical energy from the power distribution box to the electric propulsion device.

[0009] In the remainder of this specification, upstream and downstream are defined with respect to the normal power supply direction of the electrical load (from upstream to downstream), that is, from the power source to the electrical load.

[0010] Finally, in the case of a short-circuit fault, the circuit is electrically protected by at least one electrical protection device such as a fuse. Such an electrical protection device may for example be located on the power distribution box, downstream of the switching element and upstream of the power distribution harness.

[0011] The arrangement of the different elements of the circuit is called the architecture of the circuit.

[0012] With such a structure, when a short-circuit fault occurs in the power distribution harness, the electrical protection makes it possible to cut off the electrical connection between the power source and the electric propulsion device to protect the power distribution harness from degradation related to the fault.

[0013] However, when the electrical load is reversible, it can then become an electrical generator and re - supply the short - circuit fault. This is especially true when the electrical load is an electric motor. In this case, the re - supply of the electrical fault by the electric motor becoming an electrical generator is also known as the wind - milling effect.

[0014] The re - supply of a short - circuit electrical fault poses a danger to the safety of the aircraft. In fact, for example, by perforating the bulkhead of the wing, it may be able to reduce the integrity of the aircraft.

[0015] In order to avoid the re - supply of the short - circuit fault as described above, additional electrical protection must be added between the electrical wiring harness and the electrical load. This additional electrical protection must be fast and as non - dissipative as possible. Finally, there are also difficulties in the physical integration of this additional electrical protection in the aircraft.

[0016] Therefore, the object of the present invention is to propose an architecture for a circuit for supplying an electrical load to an aircraft, which makes it possible to avoid re - supplying faults of the short - circuit type while being easily integrated into the aircraft. Summary of the Invention

[0017] An embodiment relates to a circuit for supplying at least one electrical load of an aircraft. The circuit includes at least one power source and at least one main electrical protection element. The at least one power source is electrically connected to the at least one electrical load by means of at least one conductive element. The at least one main electrical protection element is positioned between the at least one power source and an upstream point of the part to be protected of the at least one conductive element during an electrical fault. Wherein, the circuit includes at least one first pyrotechnic switch and at least one first mechanical cut - off element. The at least one first pyrotechnic switch is provided with at least one first igniter element and at least one first mechanical cut - off element. The at least one first mechanical cut - off element is configured to electrically cut off at least one conductive element between the at least one power source and the upstream point of the part to be protected. And at least one second pyrotechnic switch. The at least one second pyrotechnic switch is provided with at least one second igniter element and at least one second mechanical cut - off element. The at least one second mechanical cut - off element is configured to electrically cut off at least one conductive element between a downstream point of the part to be protected and the electrical load. The first igniter element and the second igniter element are each positioned in electrical parallel with at least one main electrical protection element.

[0018] The at least one electrical load corresponds to a device that consumes electrical power during normal operation. For example, the electrical load can be a electric propulsion device including at least one electric motor powered by a high - voltage direct - current (HVDC) current, such as greater than 800 Vdc.

[0019] The power source is an element that supplies electrical energy to the circuit. The power source includes an electrical generator, such as a battery.

[0020] The conductive element is configured to circulate a current that allows powering of an electrical load. The conductive element includes a portion to be protected when an electrical fault occurs, such as a short-circuit type fault. In other words, it is the portion that must be electrically isolated after an electrical fault has occurred in the said portion. The said portion is included between an upstream point and a downstream point.

[0021] In the remainder of this specification, upstream and downstream are defined with respect to the normal supply direction of the electrical load (from upstream to downstream), that is, from the power source to the electrical load.

[0022] The main electrical protection element is configured to transmit, in the engaged state, the current that enables the electrical load to be powered, and to be in a triggered state when an electrical fault occurs in the portion of the conductive element to be protected. The engaged state is the state of the main electrical protection element during normal operation of the circuit. The positioning of the main electrical protection element between the power source and the upstream point of the portion to be protected allows the main electrical protection element to withstand the short-circuit current. The main electrical protection element is in the triggered state when the current at its terminals is greater than the maximum current.

[0023] The pyrotechnic switch can be in a closed state, in which the pyrotechnic switch allows current to pass through the conductive element, or the pyrotechnic switch can be in an open state, in which current no longer passes through the conductive element. The closed state is the state of the pyrotechnic switch during normal operation of the circuit. The pyrotechnic switch is in the open state only when an electrical fault occurs.

[0024] Each pyrotechnic switch includes an igniter element and a mechanical cut-off element.

[0025] As long as the voltage at its terminals is lower than the triggering voltage, the pyrotechnic charge controlled by the igniter element is in the rated state. The rated state is the state of the igniter element during normal operation of the circuit. When the voltage at its terminals has become greater than or equal to the triggering voltage at least once, such as when an electrical fault occurs, the pyrotechnic charge controlled by the igniter element is in the triggered state. A specific duration, called the triggering response time, is required for the igniter element to change from the rated state to the triggered state.

[0026] In some embodiments, the triggering voltage of the first igniter unit is equal to the triggering voltage of the second igniter unit.

[0027] The mechanical cut-off element is a movable element in translation, for example, which is configured to perform the electrical cut-off of a conductive element. The mechanical cut-off element can be in a rated state or in an actuated state. The rated state is the state of the mechanical cut-off element during the normal operation of the circuit. When the igniter element has moved to the triggered state, the mechanical cut-off element is in the actuated state. It takes a certain duration for the mechanical cut-off element to move from the rated state to the actuated state, which is called the mechanical response time. The mechanical cut-off element cuts the conductive element when the pyrotechnic switch is positioned. In other words, since the first mechanical cut-off element cuts the conductive element between the power supply and the upstream point of the part to be protected, the first pyrotechnic switch is positioned between the power supply and the upstream point of the part to be protected, and since the second mechanical cut-off element cuts the conductive element between the downstream point of the part to be protected and the electrical load, the second pyrotechnic switch is positioned between the downstream point of the part to be protected and the electrical load.

[0028] The first switch and the second switch are mechanically positioned in series along the conductive element. This electrical positioning enables an increase in the cut-off capacity of each pyrotechnic switch, such that the first pyrotechnic switch and the second pyrotechnic switch can be sized at an operating voltage corresponding to half of the voltage of the power supply applied to the electrical load.

[0029] When the pyrotechnic charge controlled by the igniter element is in the rated state, the mechanical cut-off element is also in the rated state, and the pyrotechnic switch is in the closed state.

[0030] When the pyrotechnic charge controlled by the igniter element is in the triggered state, the mechanical cut-off element is in the actuated state, and the pyrotechnic switch is in the open state.

[0031] The mechanical cut-off element is configured to disconnect the electrical connection when the mechanical cut-off element is actuated by the igniter element while the pyrotechnic switch is positioned in the circuit.

[0032] In the circuit according to the present invention, the first pyrotechnic switch and the second pyrotechnic switch are configured to cut the conductive element between the power supply and the electrical load when an electrical fault occurs to isolate the part to be protected. More specifically, the first pyrotechnic switch is configured to cut the conductive element between the power supply and the upstream point of the part to be protected, while the second pyrotechnic switch is configured to cut the conductive element between the downstream point of the part to be protected and the electrical load.

[0033] As described above, when the voltage between the terminals of the igniter element has become greater than or equal to the trigger voltage of the pyrotechnic charge, the pyrotechnic switch is positioned in the open state.

[0034] According to the present invention, the first igniter element and the second igniter element are each positioned in electrical parallel with at least one main electrical protection element. Thus, the voltage across the first igniter element and the second igniter element is the same and equal to the voltage across the main electrical protection element. Such that if the voltage between the terminals of the main electrical protection element becomes greater than or equal to the triggering voltage of the pyrotechnic charge, then the voltage between the terminals of the first igniter element and the second igniter element also becomes greater than or equal to the triggering voltage, causing the first igniter element and the second igniter element to switch to the triggered state, causing the first and second mechanical cut-off elements to switch to the actuated state, and ultimately causing the two pyrotechnic switches to switch to the open state. Thus, the circuit according to the present invention does not include dedicated electronics for actuating the pyrotechnic switches. It is directly the overload current associated with the short circuit that causes the triggering of the pyrotechnic switches.

[0035] When an electrical fault occurs in the part to be protected, the main electrical protection element will detect the overload current and switch to the triggered state. At least when switching from the engaged state to the triggered state, an arc is formed across the terminals of the main electrical protection element. The arc generates a voltage across the terminals of the main electrical protection element that is greater than or equal to the triggering voltage of the pyrotechnic switch, and thus also generates a voltage across the terminals of the first igniter element and the second igniter element that is greater than or equal to the triggering voltage of the pyrotechnic switch. Thus, the first and second igniter elements switch to the triggered state, thereby activating the first and second mechanical cut-off elements, and thus, the first and second mechanical cut-off elements switch to the actuated state. Finally, the first pyrotechnic switch and the second pyrotechnic switch are thus in the open state. Thus, this part of the conductive element is electrically separated from the circuit, and thus the electrical fault is also isolated. There is no longer any possibility of re-supplying the electrical fault through the electrical load, that is, even in the case of the windmill effect.

[0036] The present invention may also have one or more of the following features, either individually or in combination.

[0037] In some embodiments, the trigger response times of at least one first and at least one second igniter unit are the same.

[0038] In some embodiments, the mechanical response times of at least one first and at least one second mechanical cut-off element are the same.

[0039] In some embodiments, the trigger response times of at least one first and at least one second igniter element are less than the mechanical response times of at least one first and at least one second mechanical cut-off element.

[0040] When an electric arc is formed between the terminals of the main electrical protection element, even if the first igniter element receives the triggering voltage slightly earlier than the second igniter element, the first mechanical cut-off element switches to the actuated state only when the second igniter element has received the triggering voltage. Thus, both igniter elements are triggered before one of the mechanical elements switches to the actuated state.

[0041] In some embodiments, at least one first igniter element and / or at least one second igniter element includes at least one resistor surrounded by pyrotechnic powder or liquid.

[0042] Thus, when the resistor receives a voltage greater than its triggering voltage, the resistor heats up, generating an electric arc that powers the resistor of the igniter, causing the triggering of the pyrotechnic powder or liquid.

[0043] In some embodiments, at least one first mechanical cut-off element and / or at least one second mechanical cut-off element includes a sectioning piston.

[0044] When activated, the sectioning piston can translate to cut or slice a conductive element. The sectioning piston can be initiated by the explosion or deflagration of a pyrotechnic charge powered by an igniter element.

[0045] In some embodiments, at least one main electrical protection element has a service voltage corresponding to half of the voltage of the power supply applied to the electrical load.

[0046] Thus, the main electrical protection element is not configured to cut the electrical link between the power supply and the upstream point of the part to be protected. The main electrical protection element only enables the generation of an electric arc that will trigger the igniter element. Since the size of the main electrical protection element cannot be determined to cut the conductive element, the main electrical protection element has a reduced size, thus allowing for easier physical integration of the main electrical protection element in an aircraft.

[0047] In some embodiments, at least one main electrical protection element is a fuse.

[0048] In some embodiments, the circuit includes at least one first regulating resistor in series with the first igniter element and / or at least one second regulating resistor in series with the second igniter element.

[0049] The regulating resistor makes it possible to limit the value of the current flowing in the igniter element.

[0050] In certain embodiments, the circuit includes at least one distribution box provided with at least one switching element.

[0051] The distribution box includes at least one switching element, such as a contactor, that makes it possible to connect or disconnect the conductive element and thus ultimately connect or disconnect the electrical load.

[0052] Another aspect of the present invention relates to an aircraft comprising an electrical load powered by a circuit according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The present invention will be better understood from the following description, which relates to embodiments according to the present invention, given by way of non-limiting example and explained with reference to the attached schematic drawings, in which:

[0054] Figure 1 is a schematic diagram of a circuit according to the present invention;

[0055] Figure 2 is Figure 1 a schematic diagram of the circuit of, in which an electrical fault occurs at the level of the conductive element;

[0056] Figure 3 is Figure 2 a schematic diagram of the circuit of, in which the main electrical protection element enters a triggered state;

[0057] Figure 4 is Figure 3 a schematic diagram of the circuit of, in which an arc appears at the main electrical protection element;

[0058] Figure 5 is Figure 4 a schematic diagram of the circuit of, in which the first pyrotechnic switch and the second pyrotechnic switch enter an open state;

[0059] Figure 6 is Figure 5 a schematic diagram of the circuit of, in which a part of the conductive element is electrically insulated;

[0060] Figure 7 is Figure 1 a schematic diagram of the pyrotechnic switch of being in a closed state;

[0061] Figure 8 is Figure 7 a schematic diagram of the pyrotechnic switch of being in an open state. DETAILED DESCRIPTION

[0062] In the remainder of the present specification, upstream and downstream are defined with respect to the normal supply direction of the electrical load (from upstream to downstream), that is to say from the power supplies HV−, HV+ to the electrical load 31.

[0063] Only the elements necessary for understanding the present invention are shown. For ease of reading the drawings, the same elements have the same reference numerals in the various figures.

[0064] Figure 1Schematic diagram of a circuit 100 according to the present invention. The circuit 100 includes a high-voltage HV-, HV+ power supply 4, which is an element that supplies electrical energy to the circuit 100. The power supply 4 includes an electrical generator, such as a battery, which provides a high-voltage direct current, for example greater than 800V.

[0065] The circuit 100 includes an electrical load 31 corresponding to a power-consuming device in normal operation. In Figure 1 , the electrical load 31 is an electric propulsion device, which includes an electric motor 31 connected to an inverter 3 that converts a high-voltage direct current into an alternating current.

[0066] Current flows between the power supply 4 and the electrical load 31 through a conductive element 7. The conductive element 7 includes a portion A-B to be protected during the occurrence of a DC electrical fault, such as a short-circuit type. In other words, as Figure 2 shown, this is the A-B portion that must be electrically isolated after an electrical fault CC occurs in the A-B portion. The A-B portion is included between an upstream point A and a downstream point B.

[0067] In Figure 1 the illustrated embodiment, the circuit 100 includes a distribution box provided with a switching element 5, such as a contactor, such that the conductive element 7 can be switched on or off, and thus ultimately the electrical load 31 can be switched on or off.

[0068] The circuit 100 includes a main electrical protection element 6 located between the power supply 4 and the upstream point of the portion A-B to be protected. The main electrical protection element 4 is configured to conduct a current that allows power supply to the electrical load 31 in the engaged state and is in a triggered state when an electrical fault CC occurs in the portion A-B to be protected of the conductive element 7. The main electrical protection element 4 is in a triggered state when the current at its terminals is greater than the maximum current.

[0069] The engaged state is the state of the main electrical protection element 6 during the normal operation of the circuit 100. The main electrical protection element 6 is located between the power supply 4 and the upstream point A of the portion A-B to be protected, such that when an electrical fault CC occurs in the portion A-B to be protected of the conductive element 7, the main electrical protection element 6 is subjected to a short-circuit current.

[0070] In some embodiments, the main electrical protection element 6 has a breaking capacity lower than the value of the short-circuit current. Therefore, the main electrical protection element 6 is not configured to cut off the electrical connection between the power supply 4 and the upstream point A of the section A-B to be protected. The main electrical protection element 6 only allows an arc 61 to be generated that will trigger the pyrotechnic switches 1, 2. Since the main electrical protection element 6 does not have to be sized to cut off the conductive element 7, the main electrical protection element 6 has a reduced size, allowing for easier physical integration of the main electrical protection element 6 in an aircraft.

[0071] In Figure 1In the embodiment, the main electrical protection element 6 is a fuse.

[0072] The circuit 100 further includes a first pyrotechnic switch 1, which is provided with a first igniter element 11 and a first mechanical cut-off element 12, and the first mechanical cut-off element is configured to perform an electrical cut-off of the conductive element 7 between the power supply 4 and the upstream point A of the part A-B to be protected, and a second pyrotechnic switch 2, which is provided with a second igniter element 21 and a second mechanical cut-off element 22, and the second mechanical cut-off element is configured to perform an electrical cut-off of the conductive element 7 between the downstream point B of the part A-B to be protected and the electrical load 31.

[0073] The pyrotechnic switches 1, 2 can be in the closed state as shown in Figures 1 to 4 and 7, in which state they allow current to pass through the conductive element 7, or in the open state as shown in Figure 5 , 6 and 8, in which state the current can no longer pass through the conductive element 7. The closed state is the state of the pyrotechnic switches 1, 2 during the normal operation of the circuit 100. The pyrotechnic switches 1, 2 are only in the open state when a DC electrical fault occurs. The pyrotechnic switches 1, 2 will be described more precisely with reference to Figure 7 and 8 .

[0074] Each of the pyrotechnic switches 1, 2 includes an igniter element 11, 21 and a mechanical cut-off element 12, 22.

[0075] In Figure 7 's embodiment, the igniter elements 11, 21 include at least one resistor surrounded by pyrotechnic powder or liquid.

[0076] As shown in Figure 7 , as long as the voltage at its terminals is lower than the trigger voltage, the igniter elements 11, 21 are in the rated state. The rated state is the state of the igniter elements 11, 21 during the normal operation of the circuit 100. When the voltage across its terminals has become greater than or equal to the trigger voltage for at least an instant, for example when a DC electrical fault occurs, the igniter elements 11, 21 are in the triggered state, as shown in Figure 8 . For the igniter elements 11, 21 to transition from the rated state to the triggered state, a specific duration called the trigger response time is required.

[0077] In some embodiments, the trigger response times of the first and second igniter elements 11, 21 are the same. In some embodiments, the trigger voltage of the first igniter element 11 is equal to the trigger voltage of the second igniter element 21.

[0078] Thus, when the igniter elements 11, 21 receive a voltage greater than or equal to the trigger voltage at their terminals, the igniter elements 11, 21, which are here resistors, get hot, which actuates the pyrotechnic powder or liquid.

[0079] The first igniter element 11 and the second igniter element 21 are each positioned in electrical parallel with the main electrical protection element 6.

[0080] In Figure 1 the illustrated embodiment, the circuit 100 includes a first regulating resistor 13 in series with the first igniter element 11 and a second regulating resistor 23 in series with the second igniter element 21.

[0081] The regulating resistors 13, 23 make it possible to limit the value of the current flowing in the igniter elements 11, 21.

[0082] The mechanical cutting elements 12, 22 are movable elements configured to electrically cut the conductive element 7. In Figure 7 、 8 the illustrated embodiment, the mechanical cutting elements 12, 22 include slicing pistons.

[0083] When the mechanical cutting elements 12, 22 are activated as in Figure 8 the translatable slicing pistons cut or slice the conductive element 7. The slicing pistons can be activated by the explosion or deflagration of the igniter elements 11, 21.

[0084] The mechanical cutting elements 12, 22 can be in a rated state or in an actuated state. Figures 1 to 3 The rated state shown in and 7 is the state of the mechanical cutting elements 12, 22 during the normal operation of the circuit 100. When the igniter elements 11, 21 have entered the trigger state, the mechanical cutting elements 12, 22 are in the actuated state, as in Figure 5 、 6As shown in FIGS. 7 and 8. It takes a certain duration for the mechanical cutting elements 12, 22 to change from the rated state to the actuated state, which is called the mechanical response time. The mechanical cutting elements 12, 22 cut the conductive element 7 at the positions of the pyrotechnic switches 1, 2. Since the first mechanical cutting element 12 cuts the conductive element 7 between the power supply 4 and the upstream point A of the protected section A-B, the first pyrotechnic switch 1 is positioned between the power supply 4 and the upstream point A of the protected section A-B, and since the second mechanical cutting element 22 cuts the conductive element 7 between the downstream point B of the protected section A-B and the section 31, the second pyrotechnic switch 2 is positioned between the downstream point B of the protected section A-B and the electrical load B. The first switch 1 and the second switch 2 are mechanically positioned in series along the conductive element 7. This electrical positioning enables the cutting capacity of each pyrotechnic switch 1, 2 to be increased, such that the first pyrotechnic switch 1 and the second pyrotechnic switch 2 can be sized using an operating voltage corresponding to half of the voltage of the power supply applied to the electrical load 31.

[0085] In some embodiments, the mechanical response times of at least one first mechanical cutting element 12 and at least one second mechanical cutting element 22 are the same.

[0086] When the igniter elements 11, 21 are in the rated state, the mechanical cutting elements 12, 22 are also in the rated state, and the pyrotechnic switches 1, 2 are in the closed state.

[0087] When the igniter elements 11, 21 are in the triggered state, the mechanical cutting elements 12, 22 are in the actuated state, and the pyrotechnic switches 1, 2 are in the open state.

[0088] As described above, when the voltage across the igniter elements 11, 21 becomes greater than or equal to the trigger voltage, the pyrotechnic switches 1, 2 are positioned in the open state.

[0089] Reference will be made to Figures 1 to 6 Describe the operation of the pyrotechnic switches 1, 2 when a DC electrical fault occurs.

[0090] Figure 1 FIG. 1 shows the normal operation of the circuit 100 according to the present invention, in which the power supply 4 supplies the electrical load 31. During normal operation, the switching element 5 is in the closed state to conduct current into the conductive element 7. In addition, the first pyrotechnic switch 1 and the second pyrotechnic switch 2 are in the closed state, and the main protection element 6 is in the engaged state.

[0091] Figure 2 FIG. 2 shows the occurrence of a DC electrical fault in the conductive element 7, more precisely in the protected portion A-B of the conductive element 7.

[0092] The DC power failure causes an increase in the current flowing in the conductive element 7 so as to reach at least the maximum current value of the main power protection element 6, and causes the main power protection element 6 to switch to the triggered state as shown in Figure 3 as shown.

[0093] The transition to the triggered state of the main power protection element 6 causes an arc 61 to form between its terminals, as shown in Figure 4 as shown.

[0094] The arc 61 generates a voltage greater than or equal to the trigger voltage of the first igniter element 11 and the second igniter element 21 at the terminals of the first igniter element 11 and the second igniter element 21, each of the above terminals being positioned in electrical parallel with the main power protection element 6. Therefore, the first igniter element 11 and the second igniter element 21 switch to the triggered state, causing the first mechanical cut-off element 12 and the second mechanical cut-off element 22 to switch to the actuated state, and thus finally the two pyrotechnic switches 1, 2 to switch to the open state, as shown in Figure 5 as shown.

[0095] Finally, the first pyrotechnic switch 1 and the second pyrotechnic switch 2 are thus in the open state, as shown in Figure 6 as shown. The A - B part of the conductive element 7 is thus electrically separated from the circuit 100, and thus the DC power failure is also isolated. There is no longer any possibility of the DC power failure being re-supplied by the electrical load 31, that is, even in the case of the windmill effect.

[0096] In some embodiments, the response time of the triggering of at least one first igniter element 11 and at least one second igniter element 21 is less than the mechanical response time of at least one first mechanical cut-off element 12 and at least one second mechanical cut-off element 22. Thus, when the arc 61 forms on the main power protection element 6, even if the first igniter element 11 receives the trigger voltage slightly before the second igniter element 21, the first mechanical cut-off element 12 does not switch to the actuated state until the second igniter element 21 has received the trigger voltage. Therefore, the two igniter elements 11, 21 are triggered before one of the mechanical cut-off elements 12, 22 switches to the actuated state.

[0097] Although the present invention has been described with reference to specific embodiments, it is obvious that these examples can be modified and changed without departing from the general scope of the invention defined by the claims. In particular, the individual features of the various illustrated / described embodiments can be combined in additional embodiments. Therefore, the detailed description and the drawings should be regarded as illustrative rather than restrictive in meaning.

[0098] It is also obvious that all features described with reference to the method can be transposed to the apparatus, either individually or in combination, and conversely, all features described with reference to the apparatus can be transposed to the method, either individually or in combination.

Claims

1. A circuit (100) for supplying at least one electrical load (31) of an aircraft, the circuit (100) comprising at least one power source (4) electrically connected to the at least one electrical load (31) by means of at least one conductive element (7), and at least one main electrical protection element (6) being positioned between the at least one power source (4) and a point upstream of a section (AB) to be protected of the at least one conductive element (7) during the occurrence of an electrical fault (CC), It is characterized in that The circuit (100) comprises at least one first pyrotechnic switch (1), the first pyrotechnic switch being provided with at least one first igniter element (11) and at least one first mechanical disconnection element (12), the first mechanical disconnection element being configured to electrically disconnect the at least one conductive element (7) between the at least one power source (4) and an upstream point (A) of the part (AB) to be protected, and the circuit (100) comprises at least one second pyrotechnic switch (2) provided with at least one second igniter element (21) and at least one second mechanical disconnection element (22), the second mechanical disconnection element being configured to electrically disconnect the at least one conductive element (7) between a downstream point (B) of the part to be protected (AB) and the electrical load (31), The first igniter element (11) and the second igniter element (21) are respectively positioned in electrical parallel with the at least one main electrical protection element (6).

2. The circuit (100) according to claim 1, wherein: The response time of the triggering of the at least one first igniter element (11) and the at least one second igniter element (21) is shorter than the mechanical response time of the at least one first mechanical cutting element (12) and the at least one second mechanical cutting element (22).

3. The circuit (100) according to any one of the preceding claims, wherein: The at least one first igniter element (11) and / or the at least one second igniter element (21) comprises at least one resistor surrounded by pyrotechnic powder or liquid.

4. The circuit (100) according to any one of the preceding claims, wherein The at least one first mechanical cutting element (12) and / or the at least one second mechanical cutting element (22) comprises a cutting piston.

5. The circuit (100) according to any of the preceding claims, wherein the at least one primary electrical protection element (6) has an operating voltage corresponding to half the voltage of the power supply applied to the electrical load.

6. The circuit (100) according to any of the preceding claims, comprising at least one first adjustment resistor (13) positioned in electrical series with the first igniter element (11) and / or at least one second adjustment resistor (23) positioned in electrical series with the second igniter element (21).

7. The circuit (100) according to any of the preceding claims, comprising at least one switch box provided with at least one switching element (5).

8. An aircraft comprising an electrical load (31) powered by a circuit (100) according to any one of the preceding claims.

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