Fire detection through existing electricity meters

Abstract

The invention relates to fire detection through existing electricity meters. An auxiliary device (2) arranged to be mounted on an electricity meter (1), which can comprise a primary port (I1, A) to which the electricity meter applies a supply voltage, the auxiliary device comprising:-a secondary port (21) arranged to be connected to the primary port when the device is mounted on the electricity meter, the device thus being powered by the supply voltage; -a secondary processing unit arranged to communicate a message to the electricity meter by modulating a supply current of the device generated by the electricity meter and flowing via the primary port and the secondary port.

Description

Technical Field

[0001] The present invention relates to the field of electricity meters, and more particularly to improving existing electricity meters. Background Art

[0002] Although the possibility is extremely small, incorrect installation of an electricity meter may cause a fire.

[0003] When installers connect the power cord to the electricity meter terminal block, they place the conductors in the power terminals and then tighten them mechanically. However, if they do not tighten one of the cables sufficiently, a resistance is generated in the terminal area in question. This resistance can cause heating, which in very rare cases may lead to the appearance of a flame and thus cause a fire. Therefore, it is not the electricity meter itself that causes the fire, but the incorrect installation.

[0004] In the event of a fire in the room where the electricity meter is located, it would be very beneficial for the electricity meter to be able to detect the fire and generate an alarm message. This makes it possible to take quick measures to limit the impact of the fire. It would also be very beneficial to be able to determine whether the electricity meter (or rather its installation) is causing the fire or whether the fire is caused by other reasons.

[0005] The aim is to implement this dual detection function (detecting both the fire and the cause of the fire) in an existing electricity meter, i.e., an electricity meter that has already been designed or even installed (and thus sealed) at the customer's premises.

[0006] Therefore, this function must be implemented without any physical modification (either mechanical or electronic) to the electricity meter, and if possible, at a reduced cost. Summary of the Invention

[0007] The object of the present invention is:

[0008] - To detect whether a fire has occurred in the room where the electricity meter is located;

[0009] - To determine whether the electricity meter is the cause of the fire;

[0010] - And to do so without physically modifying the electricity meter and at a reduced cost.

[0011] To achieve this object, an auxiliary device is proposed, which is arranged to be mounted on an electricity meter. The electricity meter may include at least one main port to which the electricity meter applies a supply voltage. The auxiliary device includes:

[0012] - At least one secondary port (21), which is arranged to be connected to at least one main port when the auxiliary device is mounted on the electricity meter. The auxiliary device is thus powered by the supply voltage;

[0013] - A secondary processing unit, which is arranged to transmit at least one message to the electricity meter by modulating the supply current of the auxiliary device that is generated by the electricity meter and flows through at least one main port and at least one secondary port.

[0014] Some electricity meters have an interface that provides a supply voltage and a supply current that are accessible from outside the electricity meter. As an example, the interface is a CIS interface, which includes a power supply function and a one-way communication function, thereby making it possible to supply power to and transmit data to a CIS receiver installed on the electricity meter.

[0015] Therefore, the auxiliary device can be installed on such electricity meters, powered by the supply voltage of the interface and transmitting messages to the electricity meter by modulating the supply current. Therefore, the message is transmitted by the auxiliary device to the electricity meter using this existing interface, however, this does not provide two-way communication.

[0016] The auxiliary device can include a smoke detection device, and the message transmitted to the electricity meter can include an indication of whether there is smoke outside the electricity meter. This not only allows a fire to be detected, but also provides conclusive proof that the electricity meter is not the cause of the fire.

[0017] The auxiliary device is very inexpensive because it only requires very simple components to transmit messages to the electricity meter and detect smoke.

[0018] The auxiliary device is installed on the electricity meter without any physical modification to the electricity meter. All that is required is to load appropriate software onto the electricity meter so that the electricity meter processes the messages transmitted by the auxiliary device (and issues an alarm message, for example, in the event of a fire).

[0019] In addition, an auxiliary device as described above is proposed, and the secondary processing unit includes:

[0020] - A processing component;

[0021] - An energy reserve component;

[0022] - A switch, which is arranged such that when the switch is closed, the processing component is powered by the supply current, and when the switch is open, the processing component is powered by the reserve current from the energy reserve component;

[0023] The processing component is arranged to modulate the supply current by opening and closing the switch.

[0024] In addition, an auxiliary device as described above is proposed, wherein the secondary processing unit transmits at least one message to the electricity meter by generating at least one low state of the supply current.

[0025] Additionally, an auxiliary device as described above is proposed, wherein the secondary processing unit transmits at least one message to the electricity meter by generating a signature having high and low states with a predefined duration including a predefined sequence.

[0026] Additionally, an auxiliary device as described above is proposed, which includes a housing equipped with at least one opening and in which the secondary processing unit and a smoke detection device are integrated. The smoke detection device is arranged to detect smoke particles that have come from outside the auxiliary device and entered the auxiliary device through the at least one opening, and the at least one message contains information related to the presence of the smoke particles.

[0027] Additionally, an auxiliary device as described above is proposed, wherein the smoke detection device includes a light emitter arranged to emit an optical signal and a light receiver. The light emitter and the light receiver are located in the housing of the auxiliary device such that:

[0028] - When the housing does not contain smoke particles, the light receiver does not detect the optical signal emitted by the light emitter;

[0029] - When the housing contains smoke particles, the optical signal emitted by the light emitter is at least partially reflected by the smoke particles and detected by the light receiver.

[0030] Additionally, an electricity meter is proposed, which is arranged such that the auxiliary device as described above can be mounted on the electricity meter. The electricity meter includes:

[0031] - A current sensor arranged to measure the supply current;

[0032] - A main processing unit arranged to retrieve at least one message from the current measurement generated by the current sensor.

[0033] Additionally, an electricity meter as described above is proposed, which is arranged such that the auxiliary device as described above can be mounted on the electricity meter. The main processing unit of the electricity meter is arranged to detect a fire occurring outside the electricity meter when there are smoke particles in the auxiliary device.

[0034] Additionally, an electricity meter as described above is proposed, which further includes a temperature sensor. The main processing unit is arranged to evaluate the ambient temperature outside the electricity meter based on the temperature measurement generated by the temperature sensor. The main processing unit is arranged to detect a fire occurring outside the electricity meter in the following situations:

[0035] - There are smoke particles in the auxiliary device;

[0036] - And / or the ambient temperature is higher than a predefined threshold.

[0037] In addition, an electricity meter as described above is proposed, wherein the main processing unit is arranged to evaluate the ambient temperature based on the temperature measurement and based on the measurement of the current supplied to the installation, the power consumption of which is measured by the electricity meter.

[0038] In addition, a system is proposed that includes an auxiliary device as described above and an electricity meter as described above.

[0039] In addition, a method for detecting a fire and the cause of the fire is proposed, which is executed in the main processing unit of the electricity meter as described above and includes the following steps:

[0040] - Collecting a message containing information related to the presence of smoke;

[0041] - Detecting a fire occurring outside the electricity meter in the case where smoke particles are present in the auxiliary device.

[0042] In addition, a method as described above is proposed, which is executed in the main processing unit of the electricity meter as described above and further includes the following steps:

[0043] - Evaluating the ambient temperature outside the electricity meter;

[0044] - Detecting a fire occurring outside the electricity meter if smoke particles are present in the auxiliary device and / or if the ambient temperature is higher than a predefined threshold.

[0045] In addition, a computer program is provided that includes instructions for causing the main processing unit of the electricity meter as described above to execute the steps of the method as described above for detecting a fire and the cause of the fire.

[0046] In addition, a computer-readable storage medium is proposed, on which the computer program as described above is stored.

[0047] The present invention will be better understood from the following description of specific non-limiting embodiments of the invention. Description of the Drawings

[0048] Reference will be made to the accompanying drawings, in which:

[0049] Figure 1 Figure 1 is a perspective view of the electricity meter, its cover plate, and the auxiliary device;

[0050] Figure 2 Figure 2 is a simplified cross-sectional view of the electricity meter and the auxiliary device along a plane parallel to the front face of the electricity meter;

[0051] Figure 3 Figure 3 is a simplified view of the electricity meter and the auxiliary device;

[0052] ​​​​​​Figure 4 Figure 4 Shows the signature used by the auxiliary device to transmit a message to the electricity meter. Detailed implementation

[0053] Reference Figures 1 to 3 , the electricity meter 1 is an "existing" communication electricity meter, that is, it was designed before the creation of the present invention and did not take the auxiliary device 2 into consideration.

[0054] The electricity meter 1 is intended to measure the electricity consumption of the facility 3 and to transmit the measurement to the information system (IS) of the electricity supplier. This electricity is provided to the facility 3 through the distribution network 4. In this case, the electricity meter 1 is a single-phase electricity meter, but it can also be a multi-phase electricity meter.

[0055] The electricity meter 1 is positioned against the wall of the room and attached to the wall, thus being installed in the room.

[0056] The electricity meter 1 includes a housing 5 and a removable cover 6 (both made of, for example, plastic material). The housing 5 includes a back surface, which is also the back surface of the electricity meter 1 and is intended to be placed against and attached to the wall. The cover 6 includes a face, which is also the front face of the electricity meter 1 and can be seen and accessed by the customer or operator.

[0057] In this case, all position terms (front, back, up, down, top, bottom, etc.) should be interpreted when considering the electricity meter 1 being installed in its nominal operating position (its back attached to a vertical surface).

[0058] The electricity meter 1 includes a terminal block 7, which is placed on the front of the housing and can be accessed by removing the cover 6 (and another locked and sealed cover; not shown), and the terminal block 7 includes power terminals 8 to which the supply cable (connected to the network 4) and the cable connected to the facility 3 are connected.

[0059] The electricity meter 1 also includes sensors (not shown) for measuring the electricity consumed by the facility 3. These sensors particularly measure the current flowing through the electricity meter 1 (supplied by the network 4 to the facility 3) and the voltage applied by the network 4 at the input of the facility 3 (and the electricity meter 1).

[0060] The electricity meter 1 also includes a cut-off member 10, which is intended to selectively cut off the current supplied to the facility 3. The cut-off member 10 includes switches (in this case, single switches) for each phase of the distribution network 4.

[0061] ​​The electricity meter 1 further includes a main processing unit 12 (electronic and software). The main processing unit 12 includes at least one processing component 14, and this processing component 19 is, for example, a "general-purpose" processor, a processor dedicated to signal processing (digital signal processor (DSP)), a microcontroller, or a programmable logic circuit (such as a FPGA (field programmable gate array) or an ASIC (application specific integrated circuit)). The main processing unit 12 also includes one or more memories 15 connected to or integrated into the processing component. At least one of these memories 15 forms a computer-readable storage medium on which at least one computer program is stored, and the computer program includes instructions for causing the main processing unit 12 to execute the steps of the method for detecting a fire and the cause of the fire, which will be described later.

[0062] In this case, the main processing unit 12 includes a "measurement" microcontroller 14a and an "application" microcontroller 14b. The "measurement" microcontroller 14a especially acquires the measurements made by the sensors of the electricity meter 1 and performs certain processing operations on the measurements. The "application" microcontroller 14b especially controls the cut-off member 17. The method for detecting a fire and the cause of the fire is also executed in the application microcontroller 14b.

[0063] In this case, the main processing unit 12 and the electronic components of the cut-off member 10 are mounted on the same printed circuit 17, and the printed circuit 17 is positioned in the housing 5 parallel to the front face of the housing 5.

[0064] The electricity meter 1 further includes a CIS interface 18 (customer information system). The CIS interface 18 includes electronic components also mounted on the printed circuit 17 and three ports here called I1, 12, and A. The electronic components of the CIS interface 18 implement two functions: a power supply function and a communication function.

[0065] The power supply function involves applying a supply voltage Va between two ports I1 and A, and here the supply voltage is an AC voltage (having a frequency of, for example, 50 kHz).

[0066] The communication function involves transmitting data by applying a modulated voltage between two ports I1 and I2. Here, the modulation is amplitude modulation with a carrier frequency equal to 50 kHz. For example, the data includes power consumption readings, information about the power supply protocol, etc. This transmission is unidirectional; the electricity meter 1 transmits data and cannot receive them through this channel.

[0067] The housing 5 of the electricity meter 1 includes a receiving space 19, which is formed by a recess in the lower region of the front face of the housing 5 and is accessible when the cover 6 is removed. The receiving space 19 is designed to receive a CIS receiver (not shown) and connect the CIS receiver to the CIS interface 18.

[0068] The CIS receiver is thus powered by the power supply function of the CIS interface 18 and receives the data transmitted by the communication function.

[0069] The CIS receiver (for example, including a radio module) can thus retransmit this data to the operator or the customer.

[0070] The auxiliary device 2 is an optional and removable device mounted on the electricity meter 1. As described above, the electricity meter 1 is an existing electricity meter. Therefore, at the end of the assembly of the electricity meter 1, or when the electricity meter 1 is installed at the user's premises (or between the end of the assembly and the installation), or even when the electricity meter 1 has already been installed at the user's premises, the device 2 can be installed on the electricity meter 1.

[0071] In this case, the device 2 is intended to allow the electricity meter 1 to detect a fire occurring in the room where the electricity meter 1 is located, and also to provide conclusive proof that the electricity meter 1 is not the cause of such a fire.

[0072] The device 2 is connected to the electricity meter 1 via the CIS interface 18. It is mounted on the housing 5 by being positioned in the aforementioned accommodation space 19.

[0073] The device 2 includes at least one secondary port 21, which is arranged to be connected to at least one main port of the electricity meter 1 when the device 2 is mounted on the electricity meter 1. The device 2 includes two secondary ports 21 connected to two main ports of the electricity meter 1 in this case. The two main ports of the electricity meter 1 are port I1 and A. The device 2 is thus powered by the supply voltage Va applied between said ports by the electricity meter 1. The power consumption of the device 2 is typically 130 mW.

[0074] The device 2 includes a housing 22, and a power supply unit 23, a secondary processing unit 24, and a smoke detection device 25 are integrated in the housing 22.

[0075] In this case, the power supply unit 23 includes a rectifier 26, which rectifies the AC supply voltage Va generated by the electricity meter 1 to generate a DC supply voltage Vc (for example, 5V). The power supply unit 23 includes two input terminals E1, E2 and two output terminals S1, S2 (high-potential output terminal S1 and low-potential output terminal S2), each input terminal is connected to one of the secondary ports 21 (and thus connected to one of the main ports I1, A when the device 2 is mounted on the electricity meter 1), and the DC supply voltage Vc generated from the AC supply voltage Va by the power supply unit 23 is applied between these two output terminals.

[0076] The secondary processing unit 24 includes at least one processing component 28, and this processing component 19 is, for example, a "general-purpose" processor, a processor dedicated to signal processing (digital signal processor (DSP)), a microcontroller, or a programmable logic circuit (such as an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit)).

[0077] The secondary processing unit 24 further includes one or more memories 29 connected to or integrated into the processing component 28. At least one of these memories 29 forms a computer-readable storage medium on which at least one computer program is stored, the computer program including instructions that cause the secondary processing unit 24 to execute the steps of the smoke detection and communication methods described later.

[0078] In this case, the secondary processing unit 24 includes a microcontroller 28.

[0079] The smoke detection device 25 makes it possible to detect whether there is smoke outside the meter 1.

[0080] The housing 22 of the device 2 includes at least one opening, advantageously including at least one first opening 31 (a plurality of first openings in this case) and at least one second opening 32 (a plurality of second openings in this case).

[0081] The first opening 31 is located in the lower region of the housing 2 of the device 2 (when the device is mounted on the meter 1). The second opening 32 is located in the upper region of the housing 2 of the device 2.

[0082] The first opening 31 forms an air inlet through which air can enter the device 2. The second opening 32 forms an air outlet through which air can leave the device 2.

[0083] The first opening 31 and the second opening 32 give the device 2 a cage-like shape.

[0084] When the device 2 is mounted on the meter 1, a space is left between the device 2 and the meter 1, thereby allowing air to escape through the second opening 32.

[0085] The air inlet and the air outlet generate an air circulation. Thus, when smoke is present in the room outside the meter 1, around the meter 1, the smoke rushes into the device 2 through the air inlet and is trapped in the device.

[0086] The smoke detection device 25 detects smoke particles from outside the device 2 and entering the device 2 through at least one first opening 31.

[0087] The smoke detection device 25 includes a light emitter (a light-emitting diode (LED) 34 in this case), and a light receiver (a photodiode 35 in this case). Here, the LED 34 generates infrared light (e.g., with a wavelength of 860 nm), and the photodiode 35 can detect the infrared light when the light reaches its sensitive unit.

[0088] - The LED 34 emits an optical signal 36. The LED 34 and the photodiode 35 are located in the housing 2 of the device 2 such that: when the housing 22 does not contain smoke particles, the photodiode 22 does not detect the optical signal 36 emitted by the LED 34;

[0089] - When the housing 22 contains smoke particles, the optical signal 36 emitted by the LED 34 is at least partially reflected by the smoke particles and detected by the photodiode 35.

[0090] In this case, the LED 34 and the photodiode 35 are located in the housing 2 of the device 2 such that the LED 34 emits an optical signal along a first axis X1, and the photodiode 35 preferably detects the optical signal incident on its sensitive unit along a second axis X2 perpendicular to the first axis X1. Thus, when there are no smoke particles in the housing of the device 22, the photodiode 35 does not detect the optical signal emitted by the LED 34. On the other hand, when there are smoke particles, some of the optical signals emitted by the LED 34 are reflected by the smoke particles and reach the photodiode 35.

[0091] The photodiode 35 outputs a binary electrical signal.

[0092] When there is no smoke, this binary signal takes a first value.

[0093] When the amount of smoke particles present in the sub - part exceeds a certain threshold, the binary electrical signal takes a second value.

[0094] The microcontroller 19b includes a port P1 connected to the LED 34 and a port P2 connected to the photodiode 35. The microcontroller 28 regularly generates a voltage that is applied via the port P1 to the terminals of the LED 34 such that the LED emits an optical signal, and collects the binary electrical signal generated by the photodiode 35 via the port P2 to detect whether there is smoke in the housing 22 of the device 2 and thus whether there is smoke in the room.

[0095] Thus, the message transmitted by the device 2 to the electricity meter 1 includes information related to the presence of smoke particles in the device 2 (and thus in the room outside the device 2).

[0096] However, as described above, the communication function of the CIS interface 18 is one - way and cannot be used by the device 2 to transmit a structured message to the electricity meter 1 via the two ports I1 and I2.

[0097] The sub - processing unit 24 thus includes components that allow it to transmit messages via the sub - port 21 and thus via the main port I1, A of the electricity meter 1, which sub - ports are power supply ports (and thus were not initially provided for receiving data).

[0098] These components include an energy reserve component 40 and a switch 41, which are used to transmit a message containing information related to the presence of smoke particles to the electricity meter 1.

[0099] The energy reserve component is a storage capacitor 40, such as a 10V / 470μF chemical capacitor. The capacitance can of course be different.

[0100] The information is transmitted as follows.

[0101] The switch 41 is assembled between the power supply unit 23 and the power supply port P3 of the microcontroller 28.

[0102] The capacitor 40 has a first terminal connected to the switch 41 and the power supply port P3.

[0103] The low-potential output S2 of the power supply unit 23 is connected to the ground port P4 of the microcontroller 28. The capacitor 40 has a second terminal connected to the low-potential output S2 and the ground port P4.

[0104] The microcontroller 28 has a port CMDE, which is connected to the switch 41 and can control the switch 41 via this port and selectively place it in the conducting state (closed: CMDE is in the high state) or the locked state (open: CMDE is in the low state).

[0105] The secondary processing unit 24 of the device 2 transmits a message to the electricity meter 1 by modulating the supply current Ia generated by the electricity meter 1 and flowing through the main port I1, A and the secondary port 21 of the device 2. Therefore, the supply current Ia is the current that supplies power to the device 2 at the supply voltage Va.

[0106] The modulation is performed via the switch 41. The switch 41 is "normally closed".

[0107] When the switch 41 is closed, the microcontroller 28 is supplied with the supply current Ia provided by the power supply function of the CIS interface 18, and when the switch 41 is open, the microcontroller 28 is supplied with the reserve current Ir from the capacitor 40.

[0108] Therefore, generally, the microcontroller 28 is supplied with the supply current Ia from the electricity meter 1. The drawn supply current Ia is constant, for example about 100mA, which gives the supply current a continuous high state.

[0109] When the microcontroller 28 detects smoke particles, it controls the switch 41 for a predefined time length (e.g., 500ms) to cut off its power supply via the power supply unit 23. The device 2 (and thus specifically the microcontroller 28) is then powered by the storage capacitor 40. The device 2 thus no longer draws any current, resulting in a low state of the supply current Ia during the predefined time length.

[0110] However, the electricity meter 1 can detect changes in the supply current Ia supplied via the CIS interface 18, and can thus detect changes in the load between ports I1 and A.

[0111] In fact, the electricity meter 1 includes a current sensor 43 that measures the supply current provided by the power supply function of the CIS interface 18. Accordingly, the application microcontroller 14b retrieves information related to the presence of smoke from the current measurement generated by the current sensor 43.

[0112] Therefore, the message transmitted from the device 2 to the electricity meter 1 is transmitted via a low state with a predetermined duration. It would be possible to use low states with different durations to transmit different messages.

[0113] The message transmitted from the device 2 to the electricity meter 1 does not have to be transmitted by one or more low states of the supply current Ia.

[0114] The one or more messages can also each be transmitted by a time signature that includes a predefined sequence of high states and low states with predefined durations.

[0115] In Figure 4 a signature 44 of this kind is shown. The signature includes a first low state with a duration of 500 ms, a second low state with a duration of 300 ms, and a third low state with a duration of 400 ms. The first low state and the second low state are separated by a high state with a duration of 300 ms. The second low state and the third low state are separated by a high state with a duration of 500 ms. Composing the signature in this way allows for more robust transmission of information.

[0116] It goes without saying that it is possible to have different signatures for transmitting different messages to the electricity meter.

[0117] Therefore, if there are smoke particles in the device 2, the application microcontroller 19b detects a fire occurring outside the electricity meter 1.

[0118] Advantageously, the electricity meter 1 also uses the temperature information provided by the temperature sensor 45 included in the (existing) electricity meter.

[0119] In this case, the temperature sensor 45 is an NTC (negative temperature coefficient) thermistor.

[0120] The thermistor 45 is mounted on the printed circuit 17 and is located at a non-hot spot in the housing 5. Thus, it is far from the cut-off member 10. In this case, the thermistor 45 is located near the first corner of the printed circuit 17, while the cut-off member 10 is located near the second corner of the printed circuit 17, and the first corner and the second corner are opposite each other diagonally.

[0121] The thermistor 45 can be used to evaluate the ambient temperature in the room outside the electricity meter 1.

[0122] The temperature measured by the thermistor 45 is not the direct ambient temperature, but its representation.

[0123] The difference between the temperature measured by the thermistor 45 and the ambient temperature is a function of the current I flowing through the electricity meter 1 (and consumed by the facility 3) and thus via the cut-off member 10. The current I causes internal heating in the electricity meter 1, which will act on the temperature measured by the thermistor 45 by diffusion, regardless of the ambient temperature.

[0124] Therefore, the main processing unit 12 is arranged to evaluate the ambient temperature based on the temperature measurement generated by the thermistor 45 and based on the measurement of the current supplied to the facility 3, the power consumption of the facility 3 being measured by the electricity meter 1.

[0125] Therefore, the temperature θ measured by the thermistor 45 is a function of the ambient temperature Tamb (the ambient temperature around the electricity meter 1 in the environment outside the room where the electricity meter 1 is located) and the value of the current I (which is typically between 0 and 100 A and can be equal to 200 A in the United States).

[0126] Θ = Tamb + ΔT + K*I 2

[0127] ΔT is determined by design and is typically equal to 10 °C, and K is also a factor determined by design and typically such that:

[0128] K = 0.025 °C / A 2

[0129] As an example, if a current of 60 A is passing through the electricity meter 1, the difference between θ and Tamb will be:

[0130] (10 + 0.025 * 60 2 ) = 19 °C.

[0131] Therefore, the application microcontroller 14b measures the resistance of the thermistor 45, from which the temperature θ is derived, and then the ambient temperature Tamb is derived based on the temperature θ. Therefore, the application microcontroller 14b can estimate the ambient temperature Tamb in real time.

[0132] Then, the application microcontroller 14b detects a fire occurring outside the electricity meter 1:

[0133] - If smoke particles are present in the device 2;

[0134] - And / or if the ambient temperature is higher than a predefined threshold and is thus abnormally high.

[0135] For example, the predefined threshold is 60 °C.

[0136] When there are smoke particles, the application microcontroller 14b triggers a first alarm. When the temperature is abnormally high, the application microcontroller 14b triggers a second alarm.

[0137] If one or both of these alarms are triggered, the electricity meter 1 detects a fire. Then, the electricity meter 1 sends a corresponding alarm message to the HES (front-end system) of the IS of the electricity supplier. The alarm message can be a first alarm message indicating "abnormally high ambient temperature" or a second alarm message indicating "presence of smoke". These two alarm messages can be sent simultaneously.

[0138] As already described, a fire will generally trigger at least one of these two alarms, if not both. Thus, the electricity meter 1 will signal via the (one or more) alarm messages that it has detected a possible fire in its vicinity before it is itself destroyed.

[0139] Sending and receiving this or these alarm messages constitutes conclusive evidence that the electricity meter 1 itself is not the cause of the fire and allows the electricity meter 1 to be excluded from the investigation. In fact, if the fire originated from the electricity meter 1 (or rather, its prior incorrect installation), the electricity meter 1 would not immediately detect an abnormally high ambient temperature or smoke, as it would be burning from the inside. Thus, the electricity meter would not have time to send an alarm message to the HES of the IS, as it would be destroyed before it could do so. The fact that the HES has received at least one of these two alarm messages makes it possible to rule out the electricity meter 1 as the cause in the event of a fire.

[0140] It goes without saying that the present invention is not limited to the described embodiments, but covers any variant falling within the scope of the present invention as defined by the claims.

[0141] The auxiliary device can relay the CIS interface to a second module (CIS receiver), and the second module will be connected to the auxiliary device. Thus, the position of the auxiliary device on the electricity meter in the accommodation space that is usually reserved for the CIS receiver does not prevent a "conventional" CIS receiver from being connected to the electricity meter.

[0142] Since the consumption of the auxiliary device is typically 130 mW, the electricity meter also recognizes that when it notices a load change of at least 100 mW, the signal is a smoke detection signal, even if there is a second CIS module connected behind the auxiliary device. When using a sufficient signature (e.g., Figure 4 of the signature), the reception of the data is of course more robust.

[0143] The interface through which the auxiliary device is powered and communicates with the electricity meter does not have to be a CIS interface. It can be a different communication interface, such as a serial port, like the P1 port (which should not be confused with Figure 3Port P1 confusion in

[0144] The smoke detection devices can be different. The wavelengths of the emitted optical signals can be different. The components used can be different (e.g., using a phototransistor instead of a photodiode). More generally, any type of technology (e.g., a linear optical detector) can be used.

[0145] The auxiliary device does not have to include a smoke detection device, and thus one or more of the messages transmitted do not have to be messages notifying the electricity meter of the presence of smoke. The electricity meter can, for example, control a cut-off relay in the installation by means of the auxiliary device, thereby making it possible in particular to perform “intelligent” load shedding. In that case, the auxiliary device includes a radio module for remotely controlling the cut-off relay. In this case, after receiving the command, the cut-off relay emits an acknowledgement which is received by the auxiliary device and then retransmitted to the electricity meter by modulating the supply current.

Claims

1. An auxiliary device (2), the auxiliary device being arranged to be mounted on an electricity meter (1), the electricity meter being able to include at least one main port (I1, A), the electricity meter applying a supply voltage (Va) to the main port, the auxiliary device comprising: - at least one secondary port (21), the at least one secondary port being arranged to be connected to the at least one main port when the auxiliary device is mounted on the electricity meter, the auxiliary device thus being powered by the supply voltage; - a secondary processing unit (24), the secondary processing unit being arranged to transmit at least one message to the electricity meter by modulating the supply current (Ia) of the auxiliary device that is generated by the electricity meter and flows through the at least one main port and at least one secondary port.

2. The auxiliary device according to claim 1, wherein The secondary processing unit comprises: - a processing component (28); - an energy reserve component (40); - a switch (41), the switch being arranged such that when the switch is closed, the processing component is powered by the supply current, and when the switch is open, the processing component is powered by a reserve current from the energy reserve component; The processing component is arranged to modulate the supply current by opening and closing the switch.

3. The auxiliary device according to any one of the preceding claims, characterized in that, The secondary processing unit (24) transmits the at least one message to the electricity meter by generating at least one low state of the supply current.

4. The auxiliary device according to claim 3, characterized in that, The secondary processing unit (24) transmits the at least one message to the electricity meter by generating a signature (44) having high states and low states with a predefined duration that includes a predefined sequence.

5. The auxiliary device according to the preceding claims, characterized in that, The auxiliary device includes a housing (22), the housing being provided with at least one opening (31) and the secondary processing unit (24) and a smoke detection device (25) being integrated in the housing, the smoke detection device being arranged to detect smoke particles that have come from outside the auxiliary device and entered the auxiliary device through the at least one opening, the at least one message including information related to the presence of the smoke particles.

6. The auxiliary device according to claim 5, wherein The smoke detection device includes a light emitter (34) arranged to emit a light signal (36) and a light receiver (35), the light emitter (23) and the light receiver (35) being located in the housing (22) of the auxiliary device such that: - when the housing (22) does not contain smoke particles, the light receiver (35) does not detect the light signal emitted by the light emitter; - when the housing contains smoke particles, the light signal emitted by the light emitter is at least partially reflected by the smoke particles and detected by the light receiver.

7. An electricity meter (1), which is arranged such that an auxiliary device (2) as described in any one of the preceding claims can be mounted on the electricity meter, the electricity meter comprising: - a current sensor (43), which is arranged to measure the supply current; - a main processing unit (12), which is arranged to retrieve the at least one message from the current measurement generated by the current sensor (43).

8. The electricity meter according to claim 7, characterized in that, It is arranged such that the auxiliary device (2) as described in any one of claims 5 or 6 can be mounted on the electricity meter, and the main processing unit (12) of the electricity meter is arranged to detect a fire outside the electricity meter when there are smoke particles in the auxiliary device.

9. The electricity meter according to claim 8, characterized in that, It further includes a temperature sensor (45), and the main processing unit (12) is arranged to evaluate the ambient temperature outside the electricity meter based on the temperature measurement generated by the temperature sensor, and the main processing unit is arranged to detect a fire outside the electricity meter in the following situations: - There are smoke particles in the auxiliary device; - And / or the ambient temperature is higher than a predefined threshold.

10. The electricity meter according to claim 9, characterized in that, The processing unit is arranged to evaluate the ambient temperature based on the temperature measurement and based on the measurement of the current supplied to the facility (3), and the power consumption of the facility is measured by the electricity meter (1).

11. A system comprising an auxiliary device (2) as described in any one of claims 1 to 6 and an electricity meter (1) as described in any one of claims 7 to 10.

12. A method for detecting a fire and the cause of the fire, which is executed in the main processing unit (12) of the electricity meter (1) as described in claim 8 and includes the following steps: - Collecting a message containing information related to the presence of the smoke; - Detecting a fire outside the electricity meter in the case where there are smoke particles in the auxiliary device.

13. The method according to claim 12, characterized in that, It is executed in the main processing unit (12) of the electricity meter (1) as described in claim 9, and further includes the following steps: - Evaluating the ambient temperature outside the electricity meter; - Detecting a fire outside the electricity meter if there are smoke particles in the auxiliary device and / or if the ambient temperature is higher than a predefined threshold.

14. A computer program comprising instructions that cause the main processing unit (12) of the electricity meter as described in any one of claims 7 to 10 to execute the steps of the method for detecting the fire and the cause of the fire as described in claim 12.

15. A computer-readable storage medium having stored thereon the computer program as described in claim 14.

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