Fire detection via a pre-existing electricity meter

Abstract

Accessory equipment (2) arranged to be mounted on an electricity meter (1) that may include a primary port (I1, A) to which the electricity meter applies a supply voltage, comprising: - a secondary port (21) arranged to be connected to the primary port when the equipment is mounted on the meter, the equipment thus being electrically powered by the supply voltage; - a secondary processing unit arranged to transmit a message to the meter by modulating a supply current to the equipment produced by the meter and flowing through the primary and secondary ports. ABBREVIATED FIGURE: Fig. 1

Description

Title of the invention: Fire detection by a pre-existing electricity meter

[0001] The invention relates to the field of electric meters and, more specifically, to the improvement of pre-existing electric meters.

[0002] BACKGROUND

[0003] It is possible, although extremely unlikely, that a faulty installation of an electric meter could cause a fire.

[0004] When the installer connects the incoming electrical cables to the meter's terminal block, they position the conductors in the power terminals and then tighten them mechanically. However, if one of the cables is not tightened properly, resistance builds up at that terminal. This resistance can cause overheating which, very rarely, can lead to a flame and a fire. Therefore, the fire is not caused by the meter itself, but rather by this faulty installation.

[0005] When a fire breaks out in the room where the electricity meter is located, it is very useful for the meter to be able to detect the fire and generate an alarm message. This allows for rapid action to be taken to limit the consequences of the fire. It is also very useful to be able to determine with certainty whether the electricity meter (or rather its installation) is the source of the fire, or whether the fire has another cause.

[0006] We seek to implement this dual detection function (fire and origin of the fire) in a pre-existing meter, and therefore already designed, or even already installed at the subscriber's premises (and therefore sealed).

[0007] This function must therefore be performed without requiring any hardware modification (mechanical or electronic) of the meter and must, if possible, have a reduced cost.

[0008] OBJECT

[0009] The invention relates to:

[0010] - to detect the occurrence of a fire in a room in which there is a electricity meter;

[0011] - to determine whether or not the meter is the cause of the fire;

[0012] - and this without physically modifying the meter and at a reduced cost.

[0013] SUMMARY

[0014] To achieve this goal, an accessory device is proposed, arranged to be mounted on an electricity meter and comprising at least one primary port to which the electricity meter applies a supply voltage, the accessory equipment including:

[0015] - at least one secondary port arranged to be connected to at least one port primary when the accessory equipment is mounted on the meter, the accessory equipment thus being electrically powered by the supply voltage;

[0016] - a secondary processing unit arranged to transmit at least one message to the electric meter by modulating a supply current to the accessory equipment produced by the meter and flowing through at least one primary port and at least one secondary port.

[0017] Some electricity meters are equipped with an interface providing a supply voltage and current accessible from outside the meter. This is, for example, a TIC interface which includes a power supply function and a unidirectional communication function, and which thus allows power to be supplied and data transmitted to a TIC receiver mounted on the meter.

[0018] The accessory equipment can therefore be mounted on such a meter, powered by the interface's supply voltage, and transmit a message to the meter by modulating the supply current. The message is thus transmitted to the meter by the accessory equipment using this pre-existing interface, which, however, does not provide for bidirectional communication.

[0019] The accessory equipment may incorporate a smoke detection device, and the message transmitted to the meter may contain an indication of the presence of smoke outside the meter. This not only makes it possible to detect a fire, but also to provide formal proof that the meter is not the source of the fire.

[0020] The accessory equipment is very inexpensive because it only requires very simple components to transmit the message to the meter and to detect smoke.

[0021] The accessory equipment is mounted on the meter without requiring any hardware modification to the meter. It is sufficient to load suitable software into the meter for it to process the messages transmitted by the accessory equipment (and, for example, issue an alarm message in the event of a fire).

[0022] An accessory unit as previously described is also proposed, the secondary processing unit comprising:

[0023] - a processing component;

[0024] - an energy reserve component;

[0025] - a switch arranged so that when the switch is closed, the component 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;

[0026] the processing component being arranged to modulate the supply current by opening and closing the switch.

[0027] An accessory equipment as previously described is further proposed, in which the secondary processing unit transmits at least one message to the electric meter by producing at least one low state of the supply current.

[0028] An accessory equipment as previously described is also proposed, in which the secondary processing unit transmits at least one message to the electric meter by producing a signature comprising a predefined succession of high states and low states of predefined durations.

[0029] An accessory equipment as previously described is further proposed, comprising a housing having at least one opening and in which the secondary processing unit and a smoke detection device are integrated, the smoke detection device being arranged to detect smoke particles originating outside the accessory equipment and having entered the accessory equipment through at least one opening, the at least one message including information relating to the presence of smoke particles.

[0030] An accessory device as previously described is also proposed, comprising a light emitter arranged to emit light signals and a light receiver, which are positioned in the housing of the accessory device such that:

[0031] - when the housing does not contain smoke particles, the light receiver does not does not detect the light signals emitted by the light emitter;

[0032] - when the casing contains smoke particles, the light signals emitted by The light emitters are at least partially reflected by the smoke particles and detected by the light receiver.

[0033] An electricity meter is further proposed, arranged so that accessory equipment as previously described can be mounted on said electricity meter, the electricity meter comprising:

[0034] - a current sensor arranged to measure the supply current;

[0035] - a primary processing unit arranged to retrieve at least one message to based on current measurements produced by the current sensor.

[0036] An electric meter as previously described is further proposed, arranged so that an accessory equipment as previously described can be mounted on said electric meter, the primary processing unit of the electric meter being arranged to detect a fire occurring outside the meter in the event of the presence of smoke particles in the accessory equipment.

[0037] An electricity meter as previously described is also proposed, in which is further integrated a temperature sensor, the primary processing unit being arranged to evaluate an ambient temperature prevailing outside the meter from temperature measurements produced by the temperature sensor, the primary processing unit being arranged to detect a fire occurring outside the meter:

[0038] - in case of the presence of smoke particles in the accessory equipment;

[0039] - and / or if the ambient temperature is above a predefined threshold.

[0040] An electric meter as previously described is also proposed, the primary processing unit being arranged to evaluate the ambient temperature from temperature measurements and measurements of a current supplied to an installation whose electrical energy consumption is measured by the electric meter.

[0041] A system is also proposed comprising accessory equipment as previously described and a counter as previously described.

[0042] A method for detecting a fire and its origin is further proposed, implemented in the main processing unit of the meter as previously described, and comprising the steps of:

[0043] - acquire the message including information relating to the presence of smoke;

[0044] - detect a fire occurring outside the meter in the event of the presence of smoke particles in the accessory equipment.

[0045] A method as previously described is further proposed, implemented in the main processing unit of the meter as previously described, and further comprising the steps of:

[0046] - evaluate the ambient temperature outside the meter;

[0047] - detect a fire occurring outside the meter in the event of the presence of smoke particles in accessory equipment, and / or if the ambient temperature is above a predefined threshold.

[0048] A computer program is also proposed comprising instructions which lead the primary processing unit of the meter as previously described to execute the steps of the process of detecting a fire and the origin of the fire as previously described.

[0049] A computer-readable recording medium is also proposed, on which the computer program as previously described is recorded.

[0050] The invention will be better understood in the light of the following description of a particular, non-limiting embodiment of the invention. Brief description of the drawings

[0051] Reference will be made to the attached drawings, among which:

[0052] [Fig-1] [Fig.1] represents a perspective view of the electric meter, of its hood and accessory equipment;

[0053] [Fig.2] [Fig.2] represents a simplified cross-sectional view of the electric meter and of the accessory equipment, according to a plane parallel to the front face of the meter;

[0054] [Fig.3] [Fig.3] represents a simplified diagram of the meter and accessory equipment;

[0055] [Fig.4] [Fig.4] represents a signature used by accessory equipment for transmit a message to the counter. DETAILED DESCRIPTION

[0056] With reference to figures 1 to 3, the electric meter 1 is a "pre-existing" communicating meter, that is to say, it was designed prior to the realization of the present invention and without taking into account the accessory equipment 2.

[0057] The electricity meter 1 is intended to measure the electrical energy consumption of an installation 3 and to transmit the measurements to the Information System (IS) of the electricity supplier. This electrical energy is supplied to the installation 3 by a distribution network 4. The meter 1 is here a single-phase meter, but it could be a polyphase meter.

[0058] The meter 1 is installed in a room by being positioned against a wall of said room and fixed to the wall.

[0059] The meter 1 comprises a housing 5 and a removable cover 6 (made of plastic, for example). The housing 5 includes a rear face, which is also the rear face of the meter 1, and is intended to be applied to and fixed to the wall. The cover 6 includes a face, which is also the front face of the meter 1, and is visible and accessible by the subscriber or an operator.

[0060] Here, all position terms (front, rear, upper, lower, top, bottom, etc.) must be interpreted considering that the meter 1 is installed in its nominal operating position (its rear face fixed to a vertical surface).

[0061] The meter 1 has a terminal block 7 positioned on the front face of the box, accessible by removing the cover 6 (as well as another cover, not shown, locked and sealed), and comprising power terminals 8 to which are connected the electrical supply cables (connected to the network 4) and the cables connected to the installation 3.

[0062] The meter 1 also includes sensors (not shown) for measuring the electrical energy consumed by the installation 3. These sensors measure in particular the current flowing through the meter 1 (supplied by the network 4 to the installation 3) and the voltage applied by the network 4 at the input of the installation 3 (and of the meter 1).

[0063] The meter 1 also includes a switching device 10 which is intended to selectively cut off the current supplied to the installation 3. The switching device 10 includes a switch for each phase of the distribution network 4 (here a single switch).

[0064] The meter 1 further comprises a primary processing unit 12 (electronic and software). The primary processing unit 12 includes at least one processing component 14, which is, for example, a general-purpose processor, a processor specialized in signal processing (or DSP, for Digital Signal Processor), a microcontroller, or a programmable logic circuit such as an FPGA (for Field Programmable Gate Array) or an ASIC (for Application Specified Integrated Circuit). The primary 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 recording medium, on which is recorded at least one computer program comprising instructions which lead the primary processing unit 12 to execute the steps of the process of detecting a fire and the origin of the fire, which will be described below.

[0065] Here, the primary processing unit 12 includes a "metrology" microcontroller 14a which, in particular, acquires the measurements taken by the sensors of the counter 1 and performs certain processing on said measurements, and an "application" microcontroller 14b which, in particular, controls the cutting element 10. It is also in the application microcontroller 14b that the process of detecting a fire and the origin of the fire is implemented.

[0066] Here, the electronic components of the primary processing unit 12 and the switching element 10 are mounted on the same printed circuit board 17 positioned in the box 5 parallel to the front face thereof.

[0067] The meter 1 also includes a TIC 18 interface (for Customer Tele-Information). This TIC 18 interface includes electronic components which are also mounted on the printed circuit board 17, as well as three ports referred to here as II, 12, A. The electronic components of the TIC 18 interface implement two functions: a power supply function and a communication function.

[0068] The power supply function consists of applying between the two ports II and A a supply voltage Va which is here an alternating voltage (of frequency for example equal to 50 kHz).

[0069] The communication function consists of transmitting data by applying a modulated voltage between ports II and 12. The modulation here is amplitude modulation with a carrier frequency of 50 kHz. The data includes, for example, consumption readings, information on the subscription, etc. This transmission is unidirectional: meter 1 transmits data but cannot receive data through this channel.

[0070] The housing 5 of the meter 1 has a reception space 19, formed by a recess located at the level of a lower part of the front face of the housing 5, and ac accessible when cover 6 is removed. Receptacle 19 is designed to accommodate a TIC receiver (not shown) and to connect the TIC receiver to the TIC interface 18.

[0071] The TIC receiver is thus electrically powered by the power supply function of the TIC interface 18, and receives the data emitted by the communication function.

[0072] The TIC receiver, which integrates for example a radio module, can thus retransmit this data to an operator or to the subscriber.

[0073] Accessory equipment 2 is an optional and removable piece of equipment that is mounted on meter 1. As previously mentioned, meter 1 is a pre-existing meter. Equipment 2 can therefore be mounted on meter 1 either at the end of the assembly of meter 1, or at the time of installation of meter 1 at the subscriber's premises (or between the end of assembly and installation), or even while meter 1 is already installed at the subscriber's premises.

[0074] Equipment 2 is here intended to enable meter 1 to detect the occurrence of a fire in the room in which meter 1 is positioned, but also to provide formal proof that meter 1 is not the cause of this fire.

[0075] Equipment 2 is connected to meter 1 via TIC interface 18. It is mounted on cabinet 5, positioned in the reception space 19 which has just been mentioned.

[0076] The equipment 2 includes at least one secondary port 21 arranged to be connected to at least one primary port of the meter 1 when the equipment 2 is mounted on the meter 1. In this case, the equipment 2 includes two secondary ports 21 which are connected to two primary ports of the meter 1. The two primary ports of the meter 1 are ports II and A. The equipment 2 is thus electrically powered by the supply voltage Va applied by the meter 1 between these ports. The power consumption of the equipment 2 is typically 130 mW.

[0077] The equipment 2 includes a housing 22 inside which are integrated a power supply unit 23, a secondary processing unit 24 and a smoke detection device 25.

[0078] The power supply unit 23 here includes a rectifier 26 which rectifies the alternating supply voltage Va, produced by the counter 1, to produce a direct current supply voltage Vc (5V for example). The power supply unit 23 includes two inputs El, E2 each connected to one of the secondary ports 21 (and therefore to one of the primary ports II, A when the equipment 2 is mounted on the counter 1), and two outputs SI, S2 (one high potential output SI and one low potential output S2) between which the direct current supply voltage Vc produced by the power supply unit 23 from the alternating supply voltage Va is applied.

[0079] The secondary processing unit 24 comprises at least one processing component 28, which is, for example, a "general-purpose" processor, a processor specialized in signal processing (or DSP, for Digital Signal Processor), a microcontroller, or a programmable logic circuit such as an FPGA (Field Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit). The secondary processing unit 24 also 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 is stored at least one computer program comprising instructions that lead the secondary processing unit 24 to execute the steps of the smoke detection and communication process, which will be described below.

[0080] Here, the secondary processing unit 24 includes a microcontroller 28.

[0081] The smoke detection device 25 makes it possible to detect the presence or absence of smoke outside meter 1.

[0082] The housing 22 of the equipment 2 includes at least one opening, and advantageously at least a first opening 31 (in this case several) and at least a second opening 32 (in this case several).

[0083] The first openings 31 are positioned at the level of a lower part of the housing 22 of the equipment 2 (when the latter is mounted on the meter 1). The second openings 32 are positioned at the level of an upper portion of the housing 22 of the equipment 2.

[0084] The first openings 31 form an air inlet, through which air can enter the equipment 2. The second openings 32 form an air outlet, through which air can exit the equipment 2.

[0085] The first openings 31 and the second openings 32 give the equipment 2 a "cage" shape.

[0086] When equipment 2 is mounted on meter 1, there remains a space between equipment 2 and meter 1 allowing air to escape through the second openings 32.

[0087] The air inlet and outlet create air circulation. Thus, when smoke is present in the room outside meter 1, in the environment of meter 1, this smoke rushes into the equipment 2 via the air inlet 31 and is trapped there.

[0088] The smoke detection device 25 detects smoke particles originating from outside the equipment 2 and having entered the equipment 2 through at least one first opening 31.

[0089] The smoke detection device 25 includes a light emitter, in this case a light-emitting diode 34 (LED), and a light receiver, in this case a photodiode 35. The LED 34 generates infrared light (for example with a wavelength of 860 nm), which the photodiode 35 can detect when the light rays reach its sensitive cell.

[0090] The LED 34 emits light signals 36. The LED 34 and the photodiode 35 are positioned in the housing 22 of the equipment 2 such that: • when the housing 22 does not contain smoke particles, the photodiode 35 does not detect the light signals 36 emitted by the LED 34; • when the case 22 contains smoke particles, the light signals 36 emitted by the LED 34 are at least partially reflected by said smoke particles and are detected by the photodiode 35.

[0091] Here, the LED 34 and the photodiode 35 are positioned in the housing 22 of the equipment 2 such that the LED 34 emits light signals along a first axis XI, and the photodiode 35 optimally detects light signals arriving at its sensitive cell along a second axis X2 which is perpendicular to the first axis XL. Thus, in the absence of smoke particles in the housing 22 of the equipment 2, the photodiode 35 does not detect the light signals emitted by the LED 34. On the other hand, in the presence of smoke particles, some of the light signals emitted by the LED 34 are reflected by the smoke particles and reach the photodiode 35.

[0092] The photodiode 35 produces a binary electrical signal at its output.

[0093] In the absence of smoke, this binary signal takes a first value.

[0094] When the quantity of smoke particles present in the secondary part exceeds a certain threshold, the binary electrical signal takes a second value.

[0095] The microcontroller 28 includes a PI port connected to the LED 34 and a P2 port connected to the photodiode 35. The microcontroller 28 regularly produces a voltage which it applies to the terminals of the LED 34 via the PI port so that the latter emits light signals, and acquires via the P2 port the binary electrical signal produced by the photodiode 35 to detect the absence or presence of smoke in the housing 22 of the equipment 2 and therefore in the room.

[0096] The message, transmitted by equipment 2 to counter 1, therefore includes information relating to the presence of smoke particles in equipment 2 (and therefore in the room outside equipment 2).

[0097] However, as seen earlier, the communication function of the TIC interface 18 is unidirectional and cannot be used by equipment 2 to transmit a structured message to the counter 1 via both ports II and 12.

[0098] The secondary processing unit 24 therefore includes components enabling it to transmit messages via the secondary ports 21 and therefore via the primary ports II, A of the counter 1, which are power ports (and therefore not initially intended to receive data).

[0099] These components include an energy reserve component 40 and a switch 41, which are used to transmit to the counter 1 the message including information relating to the presence of smoke particles.

[0100] The energy reserve component is a reservoir capacitance of 40, for example a 10V / 470 pF chemical capacitor. The capacitance value could of course be different.

[0101] Information transmission works in the following manner.

[0102] The switch 41 is mounted between the high potential output SI of the power supply unit 23 and a power port P3 of the microcontroller 28.

[0103] The capacitor 40 has a first terminal which is connected to the switch 41 and to the power supply port P3.

[0104] The low potential output S2 of the power supply unit 23 is connected to a ground port P4 of the microcontroller 28. The capacitor 40 has a second terminal which is connected to the low potential output S2 and to the ground port P4.

[0105] The microcontroller 28 has a CMDE port which is connected to the switch 41 and through which it can control the switch 41 and selectively place it in a conducting state (closed: CMDE is in a high state) or blocked state (open: CMDE is in a low state).

[0106] The secondary processing unit 24 of the equipment 2 transmits the message to the counter 1 by modulating the supply current la of the equipment 2 produced by the counter 1 and flowing through the primary ports II, A and the secondary ports 21. The supply current la is therefore the current which supplies the equipment 2 under the supply voltage Va.

[0107] The modulation is carried out via switch 4L. Switch 41 is "normally closed".

[0108] When switch 41 is closed, microcontroller 28 is powered by the supply current la provided by the power supply function of interface TIC 18, and when switch 41 is open, microcontroller 28 is powered by a reserve current Ir from capacitor 40.

[0109] Thus, normally, the microcontroller 28 is powered by the supply current la from the counter 1. The supply current drawn la is constant, for example on the order of 100 mA, which gives the supply current a continuous “high state”.

[0110] When the microcontroller 28 detects smoke particles, it commands the switch 41 for a predefined duration, for example 500 ms, to cut off its power supply via the power supply unit 23. The equipment 2, and therefore in particular the microcontroller 28, is then self-powered by the reservoir capacity 40. Equipment 2 therefore no longer draws current, which produces a low state of the supply current for the predefined duration.

[0111] Now, the counter 1 is capable of detecting a variation in the supply current provided via the TIC interface 18, and therefore a variation in load between ports II and A.

[0112] The counter 1 includes a current sensor 43 which measures the supply current provided by the power supply function of the TIC interface 18. The micro controller application 14b therefore retrieves information relating to the presence of smoke from current measurements produced by this current sensor 43.

[0113] The message transmitted by equipment 2 to counter 1 is therefore transmitted via a low state of predefined duration. It would be possible to transmit different messages using low states of different durations.

[0114] The message(s) transmitted by equipment 2 to counter 1 are not necessarily transmitted by one or more low states of the supply current.

[0115] The message(s) could also each be transmitted by a time signature comprising a predefined succession of high states and low states of predefined durations.

[0116] Such a signature 44 is visible in [Fig. 4]. This signature comprises a first low state lasting 500 ms, a second low state lasting 300 ms, and a third low state lasting 400 ms. The first and second low states are separated by a high state lasting 300 ms. The second and third low states are separated by a high state lasting 500 ms. This increased complexity of the signature enhances the robustness of information transmission.

[0117] It would of course be possible to have different signatures to transmit different messages to the counter.

[0118] The application microcontroller 14b therefore detects a fire occurring outside the meter 1 in the event of the presence of smoke particles in the equipment 2.

[0119] Advantageously, the counter 1 also uses temperature information provided by a temperature sensor 45 integrated into the (pre-existing) counter.

[0120] The temperature sensor 45 is in this case a thermistor of type NTC (for Negative Temperature Coefficient).

[0121] The thermistor 45 is mounted on the printed circuit board 17 and is located at a non-hot point in the enclosure 5. It is therefore away from the switching member 10. Here, the thermistor 45 is located near a first corner of the printed circuit board 17 and the switching member 10 is located near a second corner of the printed circuit board 17, the first corner and the second corner being diagonally opposite.

[0122] This thermistor 45 can be used to evaluate the ambient temperature prevailing in the room outside of the meter 1.

[0123] The temperature measured by the thermistor 45 is not directly the ambient temperature, but an image of the latter.

[0124] The difference between the temperature measured by the thermistor 45 and the ambient temperature is a function of the current I flowing through the meter 1 (and consumed by the installation 3), and therefore via the switching device 10. The current 7 causes internal heating in the meter 1 which, by diffusion, will affect the temperature measured by the thermistor 45, regardless of the ambient temperature.

[0125] The primary processing unit 12 is therefore arranged to evaluate the ambient temperature from the temperature measurements produced by the thermistor 45 and from measurements of the current supplied to the installation 3 whose electrical energy consumption is measured by the electric meter 1.

[0126] The temperature 0 measured by the thermistor 45 is therefore a function of the ambient temperature Tamb (ambient around the meter 1 in its external environment in the room where it is located) and of the value of the current I (which can typically range from 0 to 100 A, and which can be equal to 200 A in the USA):

[0127] 0 = Tamb + AT + K*I2

[0128] AT being determined by design and typically equal to 10 °C, and K being a factor also determined by design and typically such that:

[0129] K = Q,025 °C / A2

[0130] For example, if there is a current of 60 A flowing through meter 1, there will be a difference between 0 and Tamb of:

[0131] (10 + 0.025*602)= 19°C-

[0132] The application microcontroller 14b therefore measures the resistance of the thermistor 45, deduces the temperature 0, and then deduces the ambient temperature Tamb from the temperature 0. The application microcontroller 14b can therefore estimate the ambient temperature Tamb in real time.

[0133] The application microcontroller 14b then detects a fire occurring outside the counter 1:

[0134] - in case of the presence of smoke particles in equipment 2;

[0135] - and / or if the ambient temperature is above a predefined threshold, and is therefore anor poorly raised.

[0136] The predefined threshold is for example equal to 60°C.

[0137] The application microcontroller 14b triggers a first alarm in the event of the presence of smoke particles. The application microcontroller 14b triggers a second alarm in the event of an abnormally high temperature.

[0138] If one or both of these alarms are triggered, meter 1 detects a fire. Meter 1 then sends an alarm message corresponding to the HES (Head End System) of the electricity supplier's information system. The alarm message can be a first alarm message indicating "abnormally high ambient temperature," or a second alarm message indicating "presence of smoke." Both alarm messages can be sent simultaneously.

[0139] As we have seen, a fire will generally trigger at least one of the two alarms, or even both. Meter 1 will therefore signal, via the or the alarm messages, that it detects a probable fire in its environment before it is itself destroyed.

[0140] The sending and receiving of this alarm message(s) constitute formal proof that meter 1 itself is not the source of the fire, and thus exonerates meter 1. Indeed, if the fire originates from meter 1 (or rather, its presumably faulty installation), meter 1 will not immediately detect an abnormally high ambient temperature or smoke because it is burning from within. It will therefore not have time to send an alarm message to the HES of the SI because it will be destroyed beforehand. The fact that the HES has received at least one of the two alarm messages allows it to exonerate meter 1 in the event of a fire.

[0141] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0142] The accessory equipment could relay the TIC interface to a second module (TIC receiver), which would be connected to the accessory equipment. Positioning the accessory equipment on the meter in the space normally reserved for the TIC receiver therefore does not prevent connecting a "conventional" TIC receiver to the meter.

[0143] Since the accessory equipment typically consumes 130 mW, the meter, even if there is a second TIC module connected behind the accessory equipment, recognizes that this is the smoke detection signal when it detects a load variation of at least 100 mW. Data reception is, of course, more robust with a suitable signature (that of [Fig. 4] for example).

[0144] The interface through which the accessory equipment is powered and communicates with the meter is not necessarily an ICT interface. It could be another communication interface, for example a serial port such as a PI port, not to be confused with the PI port of [Fig.3].

[0145] The smoke detection device could be different. The wavelength of the emitted light signals could be different. The components used could be different (for example, a phototransistor instead of a photodiode). More generally, any type of technology can be used (for example, a linear optical detector).

[0146] The accessory equipment does not necessarily include a smoke detection device, and the message(s) transmitted are therefore not necessarily messages informing the meter of the presence of smoke. The meter could, for example, control disconnect relays in an installation via the accessory equipment, which notably allows for "smart" load shedding. The accessory equipment It then integrates a radio module to remotely control the cut-off relays. In this case, upon receiving the command, the cut-off relay emits an acknowledgment which is received by the accessory equipment and then retransmitted to the meter by modulating the supply current.

Claims

Demands

1. Accessory equipment (2) arranged to be mounted on an electricity meter (1) which may include at least one primary port (II, A) on which the electricity meter applies a supply voltage (Va), the accessory equipment comprising: - at least one secondary port (21) arranged to be connected to at least one primary port when the accessory equipment is mounted on the meter, the accessory equipment thus being electrically supplied by the supply voltage; - a secondary processing unit (24) arranged to transmit at least one message to the electricity meter by modulating a supply current (la) of the accessory equipment produced by the meter and flowing through at least one primary port and at least one secondary port.

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

3. Accessory equipment according to any one of the preceding claims, wherein the secondary processing unit (24) transmits at least one message to the electric meter by producing at least one low state of the supply current.

4. Accessory equipment according to claim 3, wherein the secondary processing unit (24) transmits at least one message to the electric meter by producing a signature (44) comprising a predefined succession of high states and low states of predefined durations.

5. Accessory equipment according to any one of the preceding claims, comprising a housing (22) having at least one opening (31) and in which are integrated the secondary processing unit (24) and a smoke detection device (25), the smoke detection device being arranged to detect smoke particles originating outside the accessory equipment and having entered the accessory equipment through at least one opening, the at least one message including information relating to the presence of smoke particles.

6. Accessory equipment according to claim 5, the smoke detection device comprising a light emitter (34) arranged to emit light signals (36) and a light receiver (35), which are positioned in the housing (22) of the accessory equipment such that: - when the housing (22) does not contain smoke particles, the light receiver (35) does not detect the light signals emitted by the light emitter; - when the housing contains smoke particles, the light signals emitted by the light emitter are at least partially reflected by said smoke particles and detected by the light receiver.

7. Electric meter (1), arranged so that an accessory equipment (2) according to any one of the preceding claims can be mounted on said electric meter, the electric meter comprising: - a current sensor (43) arranged to measure the supply current; - a primary processing unit (12) arranged to retrieve at least one message from current measurements produced by the current sensor (43).

8. Electric meter according to claim 7, arranged so that an accessory equipment (2) according to any one of claims 5 or 6 can be mounted on said electric meter, the primary processing unit (12) of the electric meter being arranged to detect a fire occurring outside the meter in the event of the presence of smoke particles in the accessory equipment.

9. Electric meter according to claim 8, further integrating a temperature sensor (45), the primary processing unit (12) being arranged to evaluate an ambient temperature outside the meter from temperature measurements produced by the temperature sensor, the primary processing unit being arranged to detect a fire occurring outside the meter: - in the event of the presence of smoke particles in the accessory equipment; - and / or if the ambient temperature is above a predefined threshold.

10. Electric meter according to claim 9, the primary processing unit being arranged to evaluate the ambient temperature from temperature measurements and measurements of a current supplied to an installation (3) whose electrical energy consumption is measured by the electric meter (1).

11. System comprising accessory equipment (2) according to any one of claims 1 to 6 and a counter (1) according to any one of claims 7 to 1H

12. 1U. Method for detecting a fire and the origin of the fire, implemented in the main processing unit (12) of the meter (1) according to claim 8, and comprising the steps of: - acquiring the message including information relating to the presence of smoke; - detecting a fire occurring outside the meter in the event of the presence of smoke particles in the accessory equipment.

13. A method according to claim 12, implemented in the main processing unit (12) of the meter (1) according to claim 9, and further comprising the steps of: - evaluating the ambient temperature outside the meter; - detecting a fire occurring outside the meter in the event of the presence of smoke particles in the accessory equipment, and / or if the ambient temperature is above a predefined threshold.

14. Computer program comprising instructions that cause the primary processing unit (12) of the meter according to any one of claims 7 to 10 to perform the steps of the method for detecting a fire and the origin of the fire according to claim 12.

15. Computer-readable recording medium on which the computer program according to claim 14 is recorded.

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