FR3120484A1 - Device for detecting and protecting an electrical installation of an aircraft against electric arcs - Google Patents

Abstract

Device for detecting and protecting an electrical installation of an aircraft against electric arcs. This device (50) comprises a current sensor (52.1-52.n) disposed on each power supply line (40.1-40.n) connecting in parallel a high voltage direct current electrical energy source (20) and an electrical load (30), a calculation module (54) receiving the measurements of the electric current from each current sensor, calculating a relative difference of the electric current between two supply lines on the basis of said received measurements, comparing the said calculated relative difference with a predetermined threshold, and transmitting an activation signal (Sact) when the calculated relative difference is greater than the predetermined threshold, and a cut-off module (56) configured to interrupt the transmission of electrical energy upon receipt of the activation signal. This device makes it possible to effectively detect the presence of an electric arc on one of the supply lines, and therefore to avoid parasitic activation of the cut-off module. Figure 2

Description

Device for detecting and protecting an electrical installation of an aircraft against electric arcs

This application relates to a device for detecting and protecting against electric arcs in an electrical installation of an aircraft.

In the field of aeronautics, electrical installations are supplied with voltages greater than 28 Volts (V) in direct current or greater than 115 V in alternating current. Some aircraft electrical installations are supplied with a voltage of 230 V alternating current. However, with the use of high voltage, the consequences of damage linked to the appearance of electric arcs in an aircraft electrical installation increase. In addition, it is preferred to supply an aircraft electrical installation with direct current, rather than with alternating current. However, the use of direct current with high voltages also increases the potential consequences of a series electric arc.

A series electric arc is an electric arc that appears between two parts of the same power supply line, when these parts are unintentionally disconnected from each other.

Specific design rules are applied when creating an electrical installation, in order to avoid the ignition of an electric arc. In addition, there are active protections of electrical installations against electric arcs, for example based on the monitoring of voltage or electric current.

However, for the use of high voltage, the solutions currently proposed do not make it possible to avoid parasitic activations of the protection devices of electrical installations.

The present invention aims to propose a solution making it possible to overcome these drawbacks.

• une source d’énergie électrique continue haute tension configurée pour fournir de l’énergie électrique,
• une charge électrique d’un aéronef configurée pour recevoir de l’énergie électrique, et
• une pluralité de lignes d’alimentation connectées en parallèle entre la source d’énergie électrique et la charge électrique de manière à transmettre de l’énergie électrique entre la source d’énergie électrique et la charge électrique.

To this end, the subject of the invention is a device for detecting and protecting an electrical installation of an aircraft, said electrical installation comprising:

• a high voltage direct current electrical power source configured to supply electrical power,
• an electrical load of an aircraft configured to receive electrical power, and
• a plurality of power lines connected in parallel between the electric power source and the electric load so as to transmit electric power between the electric power source and the electric load.

• sur chaque ligne d’alimentation, un capteur de courant configuré pour mesurer un courant électrique traversant ladite ligne d’alimentation, et pour transmettre ladite mesure du courant électrique,
• un module de calcul configuré pour recevoir lesdites mesures du courant électrique de chaque capteur de courant, et pour chaque ligne d’alimentation, le module de calcul est configuré pour calculer une différence relative du courant électrique entre la ligne d’alimentation et au moins une autre ligne d’alimentation parmi la pluralité de lignes d’alimentation sur la base desdites mesures reçues, pour comparer ladite différence relative calculée à un premier seuil prédéterminé, et pour transmettre un signal d’activation lorsque la différence relative calculée est supérieure au premier seuil prédéterminé, et
• un module de coupure configuré pour recevoir ledit signal d’activation, et pour interrompre la transmission de l’énergie électrique entre la source d’énergie électrique et la charge électrique à réception du signal d’activation.

According to the invention, the detection and protection device comprises:

• on each supply line, a current sensor configured to measure an electric current passing through said supply line, and to transmit said measurement of the electric current,
• a calculation module configured to receive said measurements of the electric current from each current sensor, and for each supply line, the calculation module is configured to calculate a relative difference of the electric current between the supply line and at least one another one of the plurality of power lines based on said received measurements, to compare said calculated relative difference to a first predetermined threshold, and to transmit an activation signal when the calculated relative difference is greater than the first threshold predetermined, and
• a cut-off module configured to receive said activation signal, and to interrupt the transmission of electrical energy between the source of electrical energy and the electrical load upon receipt of the activation signal.

Advantageously, the invention makes it possible to monitor the difference in electric current between the different supply lines, and therefore to effectively detect the presence of an electric arc, in particular a series arc, on one of the supply lines of the 'Electrical Installation. The invention makes it possible to avoid a false detection of the formation of an electric arc, and therefore to avoid the parasitic activation of the cut-off module of the electrical installation.

In addition, the use of a plurality of power lines in parallel between the source of electrical energy and the electrical load makes it possible to control the arc voltage on the power line on which an electric arc has appeared. With a maximum arc voltage level thus limited, a series electric arc cannot be maintained and is extinguished quickly. This improves the safety of the electrical installation.

According to one characteristic, for each supply line, the breaking module comprises a breaking unit. According to this characteristic, when a relative difference of the electric current between a power supply line and at least one other calculated power supply line is greater than the first predetermined threshold, the calculation module is configured to compare the measurement of the electric current of said lines supply line with a reference value, and, when at least one of said electric current measurements is less than the reference value, for transmitting the activation signal to the cut-off unit of the supply line corresponding to said measurement, said cut-off unit being configured to interrupt the transmission of electrical energy on the supply line upon receipt of the activation signal.

According to another feature, each current sensor is configured to measure the electric current and transmit the measurement of said electric current in real time. According to this characteristic, the calculation module is configured to, for each power supply line, calculate the relative difference of the electric current and compare the calculated relative difference with the first predetermined threshold in real time. According to this characteristic, when the calculated relative difference is greater than the first predetermined threshold, the calculation module is configured to transmit the activation signal in real time. According to this characteristic, upon receipt of the activation signal, the cut-off module is configured to interrupt the transmission of electrical energy in real time.

According to another characteristic, the calculation module is configured to compare said measurements of the electric current with a reference value in real time.

According to another characteristic, for each power supply line, the calculation module is configured to calculate a relative electric current of the power supply line on the basis of the measurements received, to compare said relative electric current calculated with a second predetermined threshold, and transmitting the activation signal when said calculated relative electric current is lower than the second predetermined threshold.

According to another characteristic, for each power supply line, the calculation module is configured to calculate the relative electric current, compare said calculated relative electric current with the second predetermined threshold and transmit the activation signal in real time.

According to another characteristic, for each supply line, the breaking module comprises a breaking unit. According to this characteristic, when the calculated relative electric current is less than the second predetermined threshold, the calculation module is configured to transmit the activation signal to the cut-off unit of the supply line corresponding to said calculated relative electric current, said cut-off unit being configured to interrupt the transmission of electrical energy on the supply line upon receipt of the activation signal.

• sur chaque ligne d’alimentation de l’installation électrique, un capteur de courant configuré pour mesurer un courant électrique traversant ladite ligne d’alimentation, et pour transmettre ladite mesure du courant électrique,
• un module de calcul configuré pour recevoir lesdites mesures du courant électrique de chaque capteur de courant, et pour chaque ligne d’alimentation, le module de calcul est configuré pour calculer un courant électrique relatif de la ligne d’alimentation sur la base desdites mesures reçues, pour comparer ledit courant électrique relatif calculé à un seuil prédéterminé, dit deuxième seuil prédéterminé, et pour transmettre un signal d’activation lorsque le courant électrique relatif calculé est inférieur au deuxième seuil prédéterminé, et
• un module de coupure configuré pour recevoir ledit signal d’activation, et pour interrompre la transmission de l’énergie électrique entre la source d’énergie électrique et la charge électrique de l’installation électrique à réception du signal d’activation.

The invention also relates to a device for detecting and protecting an electrical installation of an aircraft comprising:

• on each supply line of the electrical installation, a current sensor configured to measure an electric current crossing said supply line, and to transmit said measurement of the electric current,
• a calculation module configured to receive said electrical current measurements from each current sensor, and for each power line, the calculation module is configured to calculate a relative electric current of the power line based on said received measurements , to compare said calculated relative electric current with a predetermined threshold, said second predetermined threshold, and to transmit an activation signal when the calculated relative electric current is lower than the second predetermined threshold, and
• a cut-off module configured to receive said activation signal, and to interrupt the transmission of electrical energy between the source of electrical energy and the electrical load of the electrical installation upon receipt of the activation signal.

According to one characteristic, the calculation module is also configured to, for each supply line, calculate a relative difference of the electric current between the supply line and at least one other supply line among the plurality of supply lines on the basis of said measurements received, comparing said calculated relative difference with a predetermined threshold, called first predetermined threshold, and transmitting an activation signal when the calculated relative difference is greater than the first predetermined threshold.

Other characteristics and advantages will emerge from the description of the invention which follows, description given by way of example only, with regard to the appended drawings, among which:

is a schematic top view of an aircraft comprising an electrical installation according to one embodiment of the invention,

is a schematic view of an electrical installation provided with a device for detecting and protecting against electric arcs according to one embodiment of the invention,

is a schematic view identical to the , illustrating a second embodiment of the invention, and

is a schematic view identical to the , illustrating a third embodiment of the invention.

There represents an aircraft 10 comprising an electrical installation 12, said electrical installation 12 being represented more precisely on the .

The electrical installation 12 comprises an electrical energy source 20 configured to supply electrical energy. The electrical energy source 20 comprises a positive interface comprising at least one terminal 22, referred to as the positive terminal, and a negative interface comprising at least one terminal 24, referred to as the negative terminal.

The electrical installation 12 comprises an electrical load 30 of an aircraft configured to receive electrical energy. The electric load 30 comprises a positive interface comprising at least one terminal 32, called positive terminal, and a negative interface comprising at least one terminal 34, called negative terminal.

The electrical installation 12 also comprises a plurality of supply lines 40.1-40.n. Each supply line 40.1-40.n is a high voltage direct current electrical line. The electrical installation 12 includes at least two supply lines 40.1-40.n. Preferably, the electrical installation 12 comprises two or three supply lines 40.1-40.n. In the remainder of the description, n denotes the number of supply lines 40.1-40.n, n being an integer greater than or equal to two.

According to a first embodiment shown in the , the supply lines 40.1-40.n are connected in parallel between a positive terminal 24 of the electrical energy source 20 and a positive terminal 32 of the electrical load 30 so as to transmit electrical energy supplied by the electrical energy source 20 to the electrical load 30. In this figure, the current i24 at the output of the electrical energy source 20 is equal to the current i32 at the input of the electrical load 30. All supply lines 40.1- 40.n are electrically connected to a single positive terminal 24 of the electrical energy source 20 and to a single positive terminal 32 of the electrical load 30.

Of course, the source of electrical energy can comprise a single or a plurality of terminals for each positive and negative interface; and the electrical load may include a single or a plurality of terminals for each positive and negative interface. Each supply line is connected in parallel between the terminal(s) of the electrical energy source and the terminal(s) of the electrical load.

Each supply line 40.1-40.n comprises one or a plurality of electrical components (not shown in the figures) connected to each other by electrical cables.

The electrical installation 12 is provided with a detection and protection device 50 making it possible to detect the presence of electric arcs and to protect the electrical installation 12 against these electric arcs.

On each supply line 40.1-40.n, the detection and protection device 50 includes a current sensor 52.1-52.n configured to measure the electric current i24 crossing the supply line 40.1-40.n. Each current sensor 52.1-52.n is also configured to transmit the measurement of the electric current iMES1-iMESn to a calculation module 54 of the device 50 for detection and protection.

The calculation module 54 is configured to receive the current measurements iMES1-iMESn from each current sensor 52.1-52.n. These iMES1-iMESn measurements are sent in real time by each current sensor 52.1-52.n to the calculation module 54.

The calculation module 54 is also configured, for each supply line 40.1-40.n, to calculate a relative difference of the electric current between the supply line and at least one other supply line on the basis of the measurements of current iMES1-iMESn of each current sensor 52.1-52.n received. This calculation is performed in real time by the calculation module 54.

According to the invention, a relative difference of the electric current corresponds to a difference between the electric current of a first supply line and the electric current of a second supply line, divided by the sum of the electric currents of the first and second supply lines.

According to a first configuration, the calculation module 54 calculates the relative difference of the electric current between each supply line 40.1-40.n and the same other supply line. For example, for an electrical installation 12 comprising three supply lines 40.1, 40.2, 40.3, the calculation module 54 calculates the relative difference of the electric current between the first supply line 40.1 and the second supply line 40.2, and also between the first supply line 40.1 and the third supply line 40.3. The calculation module 54 can also calculate the relative difference of the electric current between the first supply line 40.1 and the third supply line 40.3.

According to a second configuration, the calculation module 54 calculates the relative difference of the electric current between a supply line 40.1-40.n and another supply line, the supply lines being grouped together in pairs. For example, for an electrical installation 12 comprising four supply lines 40.1, 40.2, 40.3, 40.4, the calculation module 54 calculates the relative difference of the electric current between the first supply line 40.1 and the second supply line 40.2 , and also between the third supply line 40.3 and the fourth supply line 40.4.

Of course, the calculation module 54 can operate both partly according to the first configuration and partly according to the second configuration.

The calculation module 54 thus calculates the relative difference of the electric current between two electric supply lines 40.1-40.n, for each supply line 40.1-40.n. In other words, the relative difference in electric current is measured between two supply lines 40.1-40.n, each supply line 40.1-40.n being compared with at least one other supply line 40.1-40.n.

The calculation module 54 is then configured, for each power supply line 40.1-40.n, to compare the relative difference calculated with a predetermined threshold, called the first predetermined threshold. This comparison is carried out in real time by the calculation module 54.

The first predetermined threshold corresponds to a relative difference in the electric current between the two supply lines 40.1-40.n acquired during an initialization step of the electrical installation 12, that is to say under normal conditions operation of the electrical installation 12 (i.e. in the absence of any electrical fault). Each supply line 40.1-40.n is associated with a predetermined threshold. For example, for an electrical installation 12 comprising four supply lines 40.1, 40.2, 40.3, 40.4, the calculation module 54 calculates the relative difference of the electric current between the first and second supply lines 40.1, 40.2, then compares this difference calculated at a predetermined threshold (associated with the first and second supply lines 40.1, 40.2), and the calculation module 54 also calculates the relative difference of the electric current between the third and fourth supply lines 40.3, 40.4, then compares this difference calculated at another predetermined threshold (associated with the third and fourth supply lines 40.3, 40.4).

By comparing the relative difference in the electric current between the supply lines 40.1-40.n with the predetermined threshold, the detection and protection device 50 detects a relative variation in the electric current between the supply lines 40.1-40.n, which is abnormal. This relative variation of the electric current between the supply lines 40.1-40.n is representative of the presence of an electrical fault, and in particular of a series electric arc.

Under normal operating conditions, that is to say when no electric arc takes place, and according to the law of the nodes, the electric current i24 is equal to the sum of the electric currents crossing each supply line 40.1 -40.n, that is to say the sum of the electric currents iMES1-iMESn.

We note R1-Rn the resistance of each supply line 40.1-40.n. Each resistance R1-Rn corresponds to the sum of the resistances of the components of the electrical line 40.1-40.n. R1-Rn resistors may be slightly different depending on component tolerances and length of 40.1-40.n power line. Consequently, the electric currents iMES1-iMESn of each supply line 40.1-40.n may not be identical.

ΔV denotes the voltage between terminal 24 of electrical energy source 20 and terminal 32 of electrical load 30. ΔV is identical for each electrical supply line 40.1-40.n. According to Ohm's law, for each power supply line 40.1-40.n, ΔV is equal to the product of the resistance R1-Rn and the electric current iMES1-iMESn.

The relative difference of the electric current between two supply lines 40.i and 40.j (with i and j two integers different from each other between 1 and n), denoted kij, is calculated according to the formula :

With iMESi and iMESj the values of the electric current in the supply lines 40.i and 40.j respectively, and kij a value representative of the relative difference of the electric current between the two supply lines 40.i and 40.j .

The relative difference in the electric current between the two supply lines 40.i and 40.j, denoted kij, is also obtained by the formula:

With Ri and Rj the values of the resistances of the supply lines 40.i and 40.j respectively, and kij a value representative of the relative difference of the electric current between the two supply lines 40.i-40.j.

The calculation module 54 therefore calculates the values of the different kij, by calculating the relative difference of the electric current between the supply lines 40.1-40.n, two by two, on the basis of the current measurements iMES1-iMESn of each sensor of current 52.1-52.n.

The calculation module 54 then compares this calculated relative difference kij with the predetermined threshold associated with each supply line 40.1-40.n, and therefore with each kij.

Under normal operating conditions, the calculated relative difference kij is equal to the predetermined threshold, and therefore the detection and protection device 50 does not detect any relative variation in the electric current between the supply lines 40.i and 40.j. Thus, under normal operating conditions, the value kij of the relative difference of the electric current between the supply lines 40.i and 40.j is a constant.

When an electric arc 60 appears, for example on the supply line 40.1, and according to the law of nodes, the electric current i24 is equal to the sum of the electric currents crossing each supply line 40.1-40.n, c 'that is to say the sum of the electric currents iMES1'-iMESn'. As a result of the appearance of the electric arc 60, the electric currents iMES1'-iMESn' are not equal to the currents iMES1-iMESn.

R1' is the resistance of the supply line 40.1. As the electric arc 60 appeared on the supply line 40.1, the resistance R1' is not equal to the resistance R1 of the , since the electric arc 60 has a resistance Rarc. Thus, resistance R1' in the presence of an electric arc 60 on supply line 40.1 is equal to the sum of resistance R1 under normal operating conditions (ie without electric arc) and resistance Rarc.

ΔV' denotes the voltage between terminal 24 of electrical energy source 20 and terminal 32 of electrical load 30. ΔV' is identical for each electrical supply line 40.1-40.n. According to Ohm's law, for each electrical supply line 40.1-40.n, ΔV' is equal to the product of the resistance R1', R2-Rn and the electrical current iMES1'-iMESn'.

The relative difference of the electric current between the two supply lines 40.1 and 40.n, denoted k1n', is calculated according to the formula:

With R1' the value of the resistance of the power supply line 40.1 in the presence of an electric arc, R1 the value of the resistance of the power supply line 40.1 in normal operating conditions, Rarc the value of the resistance of the electric arc 60, Rn the value of the resistance of the supply line 40.n, and k1n' a value representative of the relative difference of the electric current between the two supply lines 40.1 and 40.n.

The calculation module 54 therefore calculates the value of k1n', by calculating the relative difference of the electric current between the two supply lines 40.1 and 40.n on the basis of the current measurements iMES1 and iMESn of the current sensors 52.1 and 52 .n respectively.

The calculation module 54 then compares the calculated relative difference kij' (here k1n') with the predetermined threshold associated with the supply line, and therefore with kij.

When an electric arc forms in the electrical installation 12, the calculated relative difference kij′ is greater than the predetermined threshold, and therefore the detection and protection device 50 detects a relative variation in the electric current between the supply lines 40 .i and 40.j. We note ε the relative variation of the electric current between the supply lines 40.i and 40.j. The relative difference in the electric current between the supply lines 40.i and 40.j when an electric arc occurs (denoted kij′) is therefore equal to the sum of the relative difference in the electric current between the supply lines 40.i and 40.j when no electric arc occurs (denoted kij) and the relative variation of the electric current between the supply lines 40.i and 40.j (denoted ε).

The detection and protection device 50 thus makes it possible to detect a relative variation of the electric current between two of the supply lines 40.1-40.n which is abnormal. This relative variation of the electric current results from the appearance of an electric arc 60, having a resistance Rarc. Thus, the detection and protection device 50 makes it possible to detect the presence of an electric arc 60 in the electrical installation 12.

The calculation module 54 is then configured to transmit an activation signal Sact to a cut-off module 56 of the device 50 for detection and protection when the relative difference of the electric current between two power supply lines 40.1-40.n calculated is greater than the predetermined threshold. This activation signal Sact is transmitted in real time to the breaking module 56 by the calculation module 54.

The cut-off module 56 is configured to receive the activation signal Sact and to interrupt the transmission of electrical energy between the source of electrical energy 20 and the electrical load 30 upon receipt of the activation signal Sact. The transmission of electrical energy is interrupted in real time by the breaking module 56 upon receipt of the activation signal Sact.

Thus, the detection and protection device 50 makes it possible to deactivate the transmission of electrical energy between the electrical energy source 20 and the electrical load 30 when the presence of an electric arc 60 in the electrical installation 12 is detected, which makes it possible to eliminate the electric arc 60, and therefore to protect the electrical installation 12.

The cut-off module 56 is arranged on a common section of the supply lines 40.1-40.n, downstream of the terminal 24 of the source of electrical energy 20, and upstream of the separation of the supply lines 40.1- 40.n making it possible to put the supply lines 40.1-40.n in parallel with each other.

An application example will now be described for an electrical installation 12 comprising two supply lines 40.1, 40.2 connected between a terminal 24 of an electrical energy source 20 and a terminal 32 of an electrical load 30.

The voltage ΔV between terminal 24 of electrical energy source 20 and terminal 32 of electrical load 30 is equal to 10 Volts (V), and the voltage between terminal 34 of electrical load 30 and terminal 22 of the source of electrical energy 20 is equal to 10 V.

The difference in resistance R1, R2 between the supply lines 40.1, 40.2 placed in parallel is of the order of 10%. This difference depends on the length of the supply lines 40.1, 40.2, the tolerances of the components installed on these supply lines, the assembly of the components on the supply lines, etc.

The resistance of the supply lines 40.1, 40.2 is sized to withstand a maximum voltage drop due to the formation of an electric arc.

In a first example, an electric current of 2 Amps (A) is supplied from the electric power source 20 to the electric load 30.

Under normal operating conditions, the current sensor 52.1 measures an electric current iMES1 traversing the supply line 40.1 equal to 1.05 A, and the electric sensor 52.2 measures an electric current iMES2 traversing the supply line 40.2 equal to 0.95 A. The calculation module 54 determines the value k12 of the relative difference of the electric current between the supply lines 40.1, 40.2, which is equal to 0.05. The calculation module 54 compares the value k12 with the predetermined threshold, which is equal to 0.05. The value k12 being equal to the predetermined threshold, the relative difference of the electric current between the supply lines 40.1, 40.2 calculated is not greater than the predetermined threshold. The calculation module 54 therefore does not send an activation signal to the cut-off module 56.

If an electric arc 60 appears on the supply line 40.1, with a substantially constant arc voltage equal to 20 V (directly converted into an electric arc resistance Rarc depending on the electric current flowing in the supply line 40.1), the current sensor 52.1 measures an electric current iMES1' traversing the supply line 40.1 equal to 0.525 A, and the current sensor 52.2 measures an electric current iMES2' traversing the supply line 40.2 equal to 1.475 A. The calculation module 54 determines the value k12' of the relative difference of the electric current between the supply lines 40.1, 40.2, which is equal to 0.475. The calculation module 54 compares the value k12′ with the predetermined threshold, which is equal to 0.05. The value ε of the relative variation of the electric current between the supply lines 40.1, 40.2 is therefore equal to 0.425. The relative difference of the electric current between the supply lines 40.1, 40.2 calculated is therefore greater than the predetermined threshold. The calculation module 54 therefore transmits an activation signal to the cut-off module 56.

In a second example, 10% of the nominal electric current is supplied from the electric energy source 20 to the energy load 30, i.e. an electric current of 0.2 A.

Under normal operating conditions, the current sensor 52.1 measures an electric current iMES1 traversing the supply line 40.1 equal to 0.105 A, and the current sensor 52.2 measures an electric current iMES2 traversing the supply line 40.2 equal to 0.095 A. The calculation module 54 determines the value k12 of the relative difference of the electric current between the supply lines 40.1, 40.2, which is equal to 0.005. The calculation module 54 compares the value k12 with the predetermined threshold, which is equal to 0.005. The value k12 being equal to the predetermined threshold, the relative difference of the electric current between the supply lines 40.1, 40.2 calculated is not greater than the predetermined threshold. The calculation module 54 therefore does not send an activation signal to the cut-off module 56.

If an electric arc 60 appears on the power supply line 40.1, with a substantially constant arc voltage equal to 20 V, the current sensor 52.1 measures an electric current iMES1' traversing the power supply line 40.1 equal to 0, 0525 A, and the current sensor 52.2 measures an electric current iMES2' traversing the supply line 40.2 equal to 0.1475 A. The calculation module 54 determines the value k12' of the relative difference of the electric current between the lines of power 40.1, 40.2, which is equal to 0.0475. The calculation module 54 compares the value k12′ with the predetermined threshold, which is equal to 0.005. The value ε of the relative variation of the electric current between the supply lines 40.1, 40.2 is therefore equal to 0.0425. The relative difference of the electric current between the supply lines 40.1, 40.2 calculated is therefore greater than the predetermined threshold. The calculation module 54 therefore transmits an activation signal to the cut-off module 56.

The current sensors 52.1, 52.2 are configured to measure the electric current on each supply line 40.1-40.n with a relative accuracy of 1% over the entire measurement range.

The detection and protection device according to the invention thus makes it possible to precisely detect the presence of any electric arcs on the supply lines electrically connecting the source of electric energy and the electric load, and to activate protection of the electrical installation only when an electric arc has appeared. The detection and protection device according to the invention thus makes it possible to avoid the false detection of electric arcs, and therefore the parasitic activation of the cut-off module of the electrical installation.

According to a second embodiment shown in the , the supply lines 40.1-40.n are connected in parallel between a negative terminal 34 of the electrical load 30 and a negative terminal 22 of the electrical energy source 20 so as to transmit electrical energy from the load 30 to the source of electrical energy 20. In this figure, the current i34 at the output of the electrical load 30 is equal to the current i22 at the input of the source of electrical energy 20. All the supply lines 40.1-40 .n are electrically connected to a single terminal 34 of the electrical load 30 and to a single terminal 22 of the source of electrical energy 20.

The breaking module 56 represented on the comprises a plurality of cut-off units 56.1-56.n, a cut-off unit 56.1-56.n being arranged on each supply line 40.1-40.n, downstream of terminal 34 of the electric power source 20, and downstream of the separation of the supply lines 40.1-40.n making it possible to put the supply lines 40.1-40.n in parallel with each other.

According to a first configuration, when the relative difference of the electric current between two calculated supply lines 40.1-40.n is greater than the predetermined threshold, the calculation module 54 is configured to transmit the activation signal Sact to the cut-off units 56.1 -56.n corresponding to said supply lines 40.1-40.n. Thus, only the two supply lines 40.1-40.n among which an electric arc has appeared are cut, but the other supply lines 40.1-40.n continue to transmit electrical energy between the source of electrical energy 20 and electric charge 30.

According to a second configuration, when the relative difference of the electric current between two calculated supply lines 40.1-40.n is greater than the predetermined threshold, the calculation module 54 is configured to identify the supply line 40.1-40.n on which the electric arc 60 appeared, on the basis of the measurements of the electric current provided by the current sensors 52.1-52.n. More precisely, the calculation module 54 is configured to compare the measurement of the electric current of the current sensors 52.1-52.n corresponding to said supply lines 40.1-40.n with a reference value. Each supply line 40.1-40.n is associated with a reference value characterizing said supply line. The reference values are substantially identical for each supply line 40.1-40.n, and correspond to the sum of the electric current uniformly distributed between the supply lines 40.1-40.n. Each reference value corresponds to the electric current flowing through the supply line 40.1-40.n acquired during an initialization step of the electrical installation 12, that is to say under normal operating conditions of the electrical installation 12 (i.e. in the absence of any electrical fault). These comparisons are made in real time by the calculation module 54. When at least one of the measurements of the electric current is lower than the reference value, the calculation module 54 is configured to transmit the activation signal Sact to the cut-off unit 56.1-56.n of the supply line 40.1-40.n corresponding to said measurement. Thus, only the supply line 40.1-40.n on which an electric arc has appeared is cut, but the other supply lines 40.1-40.n continue to transmit electrical energy between the source of electrical energy 20 and the electric charge 30.

According to a third embodiment shown in the , the electric power source 20 comprises a plurality of positive terminals 24.1-24.n and the electric load 30 comprises a plurality of positive terminals 32.1-31.n. Each supply line 40.1-40.n is connected in parallel between one of the terminals 24.1-24.n of the electrical energy source 20 and one of the terminals 32.1-32.n of the electrical load 30. In other words, each supply line 40.1-40.n is connected to a terminal 24.1-24.n of the electric power source 20 and to a terminal 32.1-32.n of the electric load 30, which are different from the connection terminals of 'another supply line 40.1-40.n. The cut-off module comprises a plurality of cut-off units 56.1-56.n, a cut-off unit 56.1-56.n being arranged on each supply line 40.1-40.n, downstream of the output terminal 24.1- 24.n of the electrical energy source 20.

Alternatively or in addition, after receiving the current measurements iMES1-iMESn from each current sensor 52.1-52.n, the calculation module 54 is configured, for each supply line 40.1-40.n, to calculate a current relative electrical power of the supply line 40.1-40.n on the basis of the current measurements iMES1-iMESn of each current sensor 52.1-52.n received. This calculation is performed in real time by the calculation module 54.

According to the invention, the relative electric current corresponds to the electric current of a supply line, divided by the sum of the electric current of this supply line and the electric currents of each of the supply lines in parallel with this line. power supply.

The calculation module 54 is then configured, for each electrical supply line 40.1-40.n, to compare the relative electric current calculated with a predetermined threshold, called the second predetermined threshold. This comparison is carried out in real time by the calculation module 54.

For each supply line 40.1-40.n, the second predetermined threshold corresponds to a relative electric current of the supply line 40.1-40.n acquired during an initialization step of the electrical installation 12, c that is to say under normal operating conditions of the electrical installation 12 (i.e. in the absence of any electrical fault). Each supply line 40.1-40.n is therefore associated with a predetermined threshold. For example, for an electrical installation 12 comprising two supply lines 40.1, 40.2, the calculation module 54 calculates the relative electric current of the first supply line 40.1, then compares the result of this calculation with a predetermined threshold (associated to the first supply line 40.1), and the calculation module 54 also calculates the relative electric current of the second supply line 40.2, then compares the result of this calculation with another predetermined threshold (associated with the second line d supply 40.2).

By comparing the relative electric current of each supply line 40.1-40.n to the predetermined threshold, the detection and protection device 50 detects a relative variation of the electric current in one of the supply lines 40.1-40.n, which is abnormal. This relative variation of the electric current in one of the supply lines 40.1-40.n is representative of the presence of an electrical fault, and in particular of a series electric arc.

The relative electric current of a supply line 40.i (with i an integer between 1 and n), denoted ki, is calculated according to the formula:

With iMESi the value of the electric current in the supply line 40.i, iMESj (1 ≤ j ≤ n) the value of the electric current in each supply line 40.1-40.n (including the supply line 40. i), and ki a value representative of the relative electric current in the supply line 40.i.

The relative electric current of a supply line 40.i, denoted ki, is also obtained by the formula:

With Ri the value of the resistance of the supply line 40.i, Rj (1 ≤ j ≤ n) the value of the resistances of the supply lines 40.1-40.n (including the supply line 40.i) , and ki a value representative of the relative electric current in the supply line 40.i.

The calculation module 54 therefore calculates the values of the different ki, by calculating the relative electric current of each supply line 40.1-40.n, on the basis of the current measurements iMES1-iMESn of each current sensor 52.1-52. not.

The calculation module 54 then compares the value ki with the predetermined threshold associated with each supply line 40.1-40.n.

Under normal operating conditions, the relative electric current of a power supply line 40.i calculated ki is equal to the predetermined threshold, and therefore the detection and protection device 50 does not detect any relative variation of the electric current in the line supply 40.i. Thus, under normal operating conditions, the value ki of the relative electric current of a supply line 40.i is a constant.

When an electric arc 60 appears, for example on the supply line 40.1, the relative electric current of the supply line 40.1, denoted k1, is calculated according to the formula:

With R1' the value of the resistance of the power supply line 40.1 in the presence of an electric arc, R1 the value of the resistance of the power supply line 40.1 in normal operating conditions, Rarc the value of the resistance of the electric arc 60, Rj (2≤j≤n) the value of the resistances of the supply lines 40.2-40.n, and k1 a value representative of the relative electric current in the supply line 40.1.

The calculation module 54 therefore calculates the value of k1′, by calculating the relative electric current of the supply line 40.1 on the basis of the current measurements iMES1-iMESn of the current sensors 52.1-52.n.

The calculation module 54 then compares the value of ki' (here k1') with the predetermined threshold associated with the supply line 40.i, and therefore with ki.

When an electric arc forms in the electrical installation 12, the relative electric current of the supply line on which the electric arc appeared decreases and becomes lower than the predetermined threshold, while the relative electric current of each other line supply increases and becomes higher than the predetermined threshold.

The detection and protection device 50 thus makes it possible to detect a relative variation of the electric current in one of the supply lines 40.1-40.n which is abnormal. This relative variation of the electric current results from the appearance of an electric arc 60, having a resistance Rarc. Thus, the detection and protection device 50 makes it possible to detect the presence of an electric arc 60 in the electrical installation 12.

The calculation module 54 is then configured to transmit an activation signal Sact to the cut-off module 56 when the relative electric current of a calculated power supply line 40.1-40.n is lower than the predetermined threshold. This activation signal Sact is transmitted in real time to the cut-off module 56 by the calculation module 54. The cut-off module 56 interrupts the transmission of electrical energy between the electrical energy source 20 and the electrical load 30 at receipt of the activation signal Sact.

When the cut-off module 56 comprises a plurality of cut-off units 56.1-56.n each arranged on a supply line 40.1-40.n, the calculation module 54 is configured to transmit the activation signal Sact to the cut-off unit 56.1-56.n of the supply line 40.1-40.n corresponding to the relative electric current calculated below the predetermined threshold. The cut-off unit 56.1-56.n is configured to interrupt the transmission of electrical energy on the supply line 40.1-40.n corresponding to the relative electrical current calculated below the predetermined threshold upon receipt of the activation signal Sact . Thus, only the supply line 40.1-40.n on which an electric arc has appeared is cut, but the other supply lines 40.1-40.n continue to transmit electrical energy between the source of electrical energy 20 and the electric charge 30.

According to one configuration, the calculation module 54 is configured to transmit an activation signal Sact to the cut-off module 56 when the relative electric current of a calculated power supply line 40.1-40.n is greater than the predetermined threshold. Indeed, a decrease in the electric current on a supply line where an electric arc has appeared leads to an increase in the electric current on the other supply lines (without an electric fault), and therefore an increase in the relative electric current on a line. supply is also representative of the presence of an electric arc.

Thus, the calculation module 54 makes it possible to calculate a relative distribution of the electric current between the various supply lines 40.1-40.n arranged in parallel, and to transmit an activation signal of a cut-off module when the relative distribution of the electric current between the supply lines is different from the predetermined distribution.

The same application example as the first example previously described will now be described.

Under normal operating conditions, the calculation module 54 determines the value k1 of the relative electric current of the supply line 40.1, which is equal to 0.525, and the value k2 of the relative electric current of the supply line 40.2, which is equal to 0.475. The calculation module 54 compares the values k1 and k2 with their predetermined thresholds, which are equal to 0.525 and 0.475 respectively. The values k1 and k2 being equal to the respective predetermined thresholds, the relative electric current of each power supply line 40.1, 40.2 calculated is not lower than the predetermined threshold. The calculation module 54 therefore does not send an activation signal to the cut-off module 56.

If an electric arc 60 appears on the power supply line 40.1, the calculation module 54 determines the value k1' of the relative electric current of the power supply line 40.1, which is equal to 0.2625, and the value k2' of the electric current relative of the supply line 40.2, which is equal to 0.7375. The calculation module 54 compares the value k2′ with the associated predetermined threshold, which is equal to 0.475. The relative electric current of the calculated supply line 40.2 is therefore greater than the predetermined threshold; and the calculation module 54 does not transmit an activation signal to the cut-off module 56. In parallel, the calculation module 54 compares the value k1′ with the associated predetermined threshold, which is equal to 0.525. The relative electric current of the calculated supply line 40.1 is therefore lower than the predetermined threshold; and the calculation module 54 transmits an activation signal to the cut-off module 56.

Claims (7)

Device (50) for detecting and protecting an electrical installation (12) of an aircraft (10), said electrical installation (12) comprising:

• a high voltage DC electrical power source (20) configured to supply electrical power,
• an electrical load (30) of an aircraft configured to receive electrical energy,
• a plurality of power lines (40.1-40.n) connected in parallel between the electric power source (20) and the electric load (30) so as to transmit electric power between the electric power source (20) and the electrical load (30),

characterized in that said device (50) comprises:

• on each supply line (40.1-40.n), a current sensor (52.1-52.n) configured to measure an electric current passing through said supply line (40.1-40.n), and to transmit said measurement electric current,
• a calculation module (54) configured to receive said measurements of the electric current from each current sensor (52.1-52.n), and for each supply line (40.1-40.n), the calculation module (54) is configured to calculate a relative difference in electrical current between the power line and at least one other power line among the plurality of power lines (40.1-40.n) based on said received measurements, to compare said calculated relative difference at a first predetermined threshold, and for transmitting an activation signal (Sact) when the calculated relative difference is greater than the first predetermined threshold, and
• a cut-off module (56) configured to receive said activation signal (Sact), and interrupt the transmission of electrical energy between the source of electrical energy (20) and the electrical load (30) upon receipt of the signal d activation (Sact).

Device (50) according to Claim 1, characterized in that each current sensor (52.1-52.n) is configured to measure the electric current and transmit the measurement of said electric current in real time, in that the calculation module ( 54) is configured to, for each supply line (40.1-40.n), calculate the relative difference of the electric current, to compare the relative difference calculated with the first predetermined threshold and to transmit the activation signal (Sact) in real time, and in that the cut-off module is configured to interrupt the transmission of electrical energy in real time. Device (50) according to one of Claims 1 or 2, characterized in that, for each supply line (40.1-40.n), the cut-off module (56) comprises a cut-off unit (56.1-56). n), in that, when a relative difference of the electric current between a supply line and at least one other calculated supply line is greater than the first predetermined threshold, the calculation module (54) is configured to compare the measuring the electric current of said supply lines (40.1-40.n) with a reference value, and, when at least one of said measuring electric current is lower than the reference value, for transmitting the activation signal ( Sact) to the cut-off unit (56.1-56.n) of the power supply line (40.1-40.n) corresponding to said measurement, said cut-off unit (56.1-56.n) being configured to interrupt the transmission electrical energy on the supply line (40.1-40.n) upon receipt of the activation signal (Sact). Device (50) according to Claim 3, characterized in that the calculation module (54) is configured to compare the said measurements of the electric current with a reference value in real time. Device (50) according to one of Claims 1 to 4, characterized in that, for each supply line (40.1-40.n), the calculation module (54) is configured to calculate a relative electric current of the power supply line (40.1-40.n) on the basis of the measurements received, comparing said calculated relative electric current with a second predetermined threshold, and transmitting the activation signal (Sact) when said calculated relative electric current is lower than the second predetermined threshold. Device (50) according to Claim 5, characterized in that the calculation module (54) is configured to, for each supply line (40.1-40.n), calculate the relative electric current, compare the said calculated relative electric current at the second predetermined threshold and transmitting the activation signal (Sact) in real time. Device (50) according to one of Claims 5 or 6, characterized in that, for each supply line (40.1-40.n), the cut-off module (56) comprises a cut-off unit (56.1-56). n), in that, when the calculated relative electric current is lower than the second predetermined threshold, the calculation module (54) is configured to transmit the activation signal (Sact) to the breaking unit (56.1-56. n) of the power supply line (40.1-40.n) corresponding to said calculated relative electric current, said cut-off unit (56.1-56.n) being configured to interrupt the transmission of electric power on the power supply line (40.1-40.n) upon receipt of the activation signal (Sact).