Selection of phases for communication by a plc

Abstract

An electricity meter (1) arranged to measure electrical energy supplied to a facility by a distribution network (2) comprising a plurality of phases (3), the electricity meter comprising: a communication module (5) arranged to enable communication by power line communication; a switching circuit (10) arranged to selectively connect the communication module (5) to one of the phases; a processor unit (6) arranged to control the switching circuit to connect the communication module to an optimized phase of the phases (3), the optimized phase being dynamically selected to optimize a quality of communication by power line communication.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of electricity meters. BACKGROUND

[0002] Modern electricity meters are so-called "smart" electronic meters, which are of course designed to measure the electrical energy supplied to an electrical installation by a distributor via a distribution network, but which are also able to perform a certain number of additional functions: for example, management of taxes by receiving instructions, remote meter reading, and programming of remote customer information, etc.

[0003] In order to communicate with the outside, and for example with another meter, with a data concentrator, or with a server of the information system (IS) of the energy distributor (optionally via another meter or data concentrator), the meter is conventionally equipped with a communication module which enables communication by power line communication (PLC).

[0004] Generally, all three-phase meters inject the PLC signal on the same predetermined phase of the distribution network, which is conventionally phase 1. Thus, in a network of meters comprising only three-phase meters, all the meters inject the normal PLC signal on the same phase, and the quality of communication is generally satisfactory.

[0005] However, a network of meters comprises both three-phase meters and single-phase meters. However, if the meter closest to a three-phase meter is a single-phase meter, which is connected to a phase other than phase 1, the quality of communication then depends on the capacitive coupling between the cables, the quality of which can be very variable and very dependent on the environment. SUMMARY

[0006] The aim of the present invention is to improve the communication by power line communication in a network of electricity meters comprising both three-phase electricity meters and single-phase electricity meters.

[0007] To achieve this aim, an electricity meter is proposed, which is arranged to measure the electrical energy supplied to an installation by a distribution network comprising a plurality of phases, the electricity meter comprising:

[0008] a communication module arranged to enable communication by power line communication;

[0009] a switching circuit arranged to selectively connect the communication module to one of the phases;

[0010] a processor unit arranged to control the switching circuit to connect the communication module to an optimized phase among the phases, the optimized phase being dynamically selected to optimize the quality of communication by power line communication.

[0011] The processor unit of the meter according to the invention thus controls the switching circuit so that it connects the communication module to the optimized phase, which is dynamically selected to optimize the quality of communication.

[0012] Therefore, the quality of the communication is always satisfactory, regardless of which meter, whether three-phase or single-phase, is located in the vicinity of the meter according to the application and communicates with the meter according to the application.

[0013] In addition, an electricity meter is proposed, such as the one described above, wherein the processor unit is arranged to evaluate the quality of the communication by power line communication when the communication module is connected to each phase, and to select the optimized phase as a function of the result of this evaluation.

[0014] In addition, an electricity meter is proposed, such as the one described above, the quality of the communication by power line communication being evaluated as a function of at least one quality parameter comprising the signal-to-noise level and / or the frame exchange success rate.

[0015] In addition, an electricity meter is proposed, such as the one described above, wherein the signal-to-noise level is coded between 0 and 255 when the PLC G3 technology is used to implement the communication by power line communication, and wherein the signal-to-noise level is evaluated in dB when the PLC PRIME technology is used to implement the communication by power line communication.

[0016] In addition, an electricity meter is proposed, such as the one described above, wherein the processor unit is arranged to implement the following testing and connection steps:

[0017] controlling the switching circuit so that it successively connects the communication module to each phase;

[0018] for each phase, evaluating or obtaining a quality parameter when the communication module is connected to said phase;

[0019] selecting the phase for which the quality parameter is the greatest as the optimized phase, and controlling the switching circuit so that it connects the communication module to the optimized phase.

[0020] In addition, an electricity meter is proposed, such as the one described above, wherein the processor unit is arranged to implement the testing and connection steps at regular intervals.

[0021] In addition, an electricity meter is proposed, such as the one described above, wherein the processor unit is arranged to:

[0022] evaluate or obtain a quality parameter when the communication module is connected to the current phase;

[0023] implement the testing and connection steps when the quality parameter becomes less than a predefined threshold.

[0024] In addition, an electricity meter is proposed, such as the one described above, wherein the processor unit is arranged to receive a selection command transmitted by an external entity, to extract from the selection command an identifier of the optimized phase that has been selected by the external entity, and to control the switching circuit so as to connect the communication module to said optimized phase.

[0025] Further, an electricity meter is proposed as described above, wherein for each phase the switching circuit comprises a monolithic circuit comprising:

[0026] an input connected to the communication module and an output connected to said phase;

[0027] a switching element comprising two transistors and arranged to selectively cut off the connection between the input and the output or to enable said connection by passing a positive and a negative alternation of a PLC signal emitted by or intended for the communication module;

[0028] a command circuit arranged to receive a primary command signal generated by the processor unit and to generate a secondary command signal to control the switching element.

[0029] Further, a selection method is proposed which is implemented in a meter such as described above and comprises the following testing and connecting steps:

[0030] controlling the switching circuit so that it successively connects the communication module to each phase;

[0031] for each phase, evaluating or acquiring a quality parameter when the communication module is connected to said phase;

[0032] selecting the phase with the largest quality parameter as an optimized phase and controlling the switching circuit so that it connects the communication module to the optimized phase.

[0033] Further, a computer program is proposed comprising instructions to cause a processor unit of an electricity meter such as described above to perform the steps of a selection method such as described above.

[0034] Further, a computer readable storage medium is proposed on which a computer program such as described above is stored.

[0035] The application will be best understood according to the following description of specific non-limiting embodiments of the application. BRIEF DESCRIPTION OF DRAWINGS

[0036] Reference will be made to the drawings in which:

[0037] [ Figure 1 ] Figure 1 represents an electricity meter according to the application;

[0038] [ Figure 2 ] Figure 2 represents a switching circuit;

[0039] [ Figure 3 ] Figure 3 represents the steps of a selection method according to a first embodiment;

[0040] [ Figure 4 ] Figure 4 represent the steps of the selection method according to the second embodiment. DETAILED DESCRIPTION

[0041] With reference to Figure 1 The electricity meter 1 according to the present application is a three-phase meter, which is intended to measure the electric energy supplied through a distribution network 2 to an electrical installation of a subscriber.

[0042] The distribution network 2 comprises a plurality, in this case three phases 3 (and a neutral, not shown): phase 3a, phase 3b and phase 3c. Phase 3a is the above-mentioned phase 1.

[0043] The meter 1 comprises three input ports 4, each connected to one of the phases 3 of the distribution network: input port 4a, input port 4b and input port 4c.

[0044] The meter 1 further comprises voltage and current sensors (not shown), which measure, for each phase 3, the phase voltage present on said phase 3 and the phase current circulating on said phase 3.

[0045] The meter 1 additionally comprises a communication module 5, which is arranged to enable communication through power line communication (PLC). The communication module 5 is designed to inject an outgoing PLC signal on one of the phases 3 (it can be seen that this phase is not systematically the same) and to acquire an incoming PLC signal on said phase 3.

[0046] The meter 1 further comprises a processor unit 6, which is an electronic and software unit and comprises one or more processor components installed on one or more electronic boards.

[0047] The processor component(s) comprise, for example, a "general purpose" processor, a processor dedicated to processing signals (or DSP, digital signal processor), a microcontroller, or indeed programmable logic circuits such as FPGAs (field programmable gate arrays) or ASICs (application specific integrated circuits). The processor components are adapted to execute program instructions. In this case, the processor unit 6 comprises, inter alia, an application microcontroller 7 of the meter 1.

[0048] The processor unit 6 further comprises one or more memories 8. At least one of the memories 8 forms a computer-readable storage medium 8 on which a computer program is stored, the computer program comprising instructions for causing the processor unit 6 to execute at least some of the steps of the selection method which will be described below.

[0049] The meter 1 further comprises a switching circuit 10, which is able to selectively connect the communication module 5 to one of the phases.

[0050] For each phase 3, the switching circuit 10 comprises a monolithic circuit 11; there are therefore monolithic circuit 11a, monolithic circuit 11b and monolithic circuit 11c.

[0051] With reference to Figure 2 Each monolithic circuit 11 comprises an input end E connected to an input / output end of the communication module 5 and an output end S connected to one (single) phase 3 via the associated input port 4.

[0052] The monolithic circuit 11 further comprises a switching element 12 arranged to selectively cut off the connection between the input end E and the output end S of the monolithic circuit 11 or to enable said connection by passing the positive and negative alternations of the outbound or inbound PLC signals emitted from or to the communication module 5, at a frequency between 30 Khz and 500 Khz.

[0053] The switching element 12 comprises two MOSFET transistors 13a, 13b (at the channel N).

[0054] The drain of the first transistor 13a is connected to the input end E of the monolithic circuit 11. The sources of the first transistor 13a and of the second transistor 13b are connected to each other. The gates of the first transistor 13a and of the second transistor 13b are connected to each other. A resistor 14 and a capacitor 15 are installed in parallel, each having a first terminal connected to the source and a second terminal connected to the gate of the transistors 13a, 13b.

[0055] In addition, the monolithic circuit 11 comprises a command circuit 16 arranged to receive a primary command signal Scp generated by the microcontroller 7 and to generate a secondary command signal Scs to control the switching element 12.

[0056] The primary command signal Scp is a 3.3 V voltage signal in the high state. The secondary command signal Scs is a 15 V voltage signal in the high state. The command circuit 16 is therefore adapted to the primary command signal Scp to command the switching element 12.

[0057] The command circuit 16 comprises two bipolar transistors 17a, 17b: the transistor 17a is of the NPN type and the transistor 17b is of the PNP type.

[0058] The base of the transistor 17a is connected to an output of the microcontroller 7 via a resistor 19. The emitter of the transistor 17a is connected to ground GND. The collector of the transistor 17a is connected to the base of the transistor 17b via a resistor 20. The base of the transistor 17b is connected to the power supply VCC via a resistor 21. The power supply Vcc is supplied at a direct voltage of 15 V. The emitter of the transistor 17b is connected to the power supply Vcc. The collector of the transistor 17b is connected to a first terminal of a resistor 22, the second terminal of the resistor 22 being connected to a first terminal of a resistor 23. The second terminal of the resistor 23 is connected to ground.

[0059] The second terminal of the resistor 22 is also connected to a first terminal of a capacitor 24, the second terminal of the capacitor 24 being connected to ground. The second terminal of the resistor 22 is also connected to the gate of the transistors 13a, 13b.

[0060] The monolithic circuit 11 also comprises a protection circuit 26 against surges of the command circuit, which protects against voltage increases on the power supply Vcc. The protection circuit 26 comprises two Schottky diodes 27a, 27b. The cathode of the Schottky diode 27a is connected to the power supply Vcc. The cathode of the Schottky diode 27b is connected to the anode of the Schottky diode 27a. The anode of the Schottky diode 27b is connected to ground. The anode of the Schottky diode 27a is connected to the gate of the transistors 13a, 13b.

[0061] The monolithic circuit 11 also comprises a front circuit 30 connected to the output S of the monolithic circuit 11 and thus to phase 3.

[0062] The front circuit 30 comprises a lightning protection circuit 31 (for example, 2 kV) comprising a resistor 32 having a first terminal connected to the output S and a varistor 33 having a first terminal connected to ground and a second terminal connected to a second terminal of the resistor 32.

[0063] The front circuit 30 also comprises a coupling capacitor 34, making it possible to inject an outgoing PLC signal onto phase 3. The coupling capacitor 34 blocks 50 Hz, i.e. the frequency of the phase voltage and of the phase current. A first terminal of the coupling capacitor 34 is connected to the second terminal of the resistor 32.

[0064] The front circuit 30 additionally comprises an "energy storage circuit" 36, which makes it possible to close the input circuit at 50 Hz when the switching element 12 is open, without affecting the high-frequency signals (> 10 Khz - and thus the PLC signals) when the switching element 12 is closed.

[0065] The energy storage circuit 36 comprises a resistor 37 and an inductor 38. The first terminal of the resistor 37 is connected to the second terminal of the coupling capacitor 34 and to the drain of the transistor 13b. The inductor 38 has a first terminal connected to the second terminal of the resistor 37 and a second terminal connected to ground.

[0066] The monolithic circuit 11 also comprises a protection circuit 39 which resists surges of the switching element 12 when it is open.

[0067] The protection circuit 39 comprises a bidirectional Transil diode 40 having a first terminal connected to the input E of the monolithic circuit 11 and to the drain of the transistor 13a, and a second terminal connected to the drain of the transistor 13b.

[0068] The protection circuit 39 makes it possible to limit the voltage at the terminals of the transistors 13a, 13b to 10 V when they are disconnected (blocked).

[0069] The monolithic circuit 11 makes it possible to implement the connection between phase 3 of the distribution network 2 and the output of the communication module 5 by the above-mentioned protection. The primary command signal Scp from the microcontroller 7 makes it possible to control the two transistors 13a, 13b to enable or, on the contrary, to disable the transmission of the PLC signal.

[0070] Thus, when the microcontroller 7 generates on its output the primary command signal Scp in the high state, the monolithic circuit 11 lets the PLC signal pass between the communication module 5 and the phase 3, which is thus the phase selected to implement the PLC communication. On the contrary, when the microcontroller 7 generates on its output the primary command signal Scp in the low state, the PLC communication is carried out on another phase. Only one phase is selected at a time.

[0071] The phase in question is selected to optimize the quality of the PLC communication: reference will be made to the "optimized" phase.

[0072] In the meter 1, when the communication module 5 is connected to each phase, the microcontroller 7 is indeed able to evaluate the quality of the PLC communication and, as a consequence, to select dynamically the optimized phase according to the result of this evaluation. By "dynamically", it is meant that according to the evolution of the quality of the PLC communication, the selection can evolve over time.

[0073] The microcontroller 7 evaluates the quality of the PLC communication according to at least one quality parameter. The microcontroller 7 can evaluate (via a measurement, a calculation, etc.) the value of the quality parameter or acquire said value.

[0074] The quality parameter is for example the signal-to-noise ratio level.

[0075] When the PLC G3 technology is used to implement the PLC communication, the signal-to-noise ratio level is coded between 0 and 255, therefore the LQI (Link Quality Indicator) is referred to.

[0076] When the PLC PRIME technology is used to implement the PLC communication, the signal-to-noise ratio level is evaluated in dB; therefore the SNR signal-to-noise ratio is referred to.

[0077] The quality parameter is for example the frame exchange success rate.

[0078] In fact, when the meter 1 is connected to the data concentrator, the meter 1 conventionally receives information representative of the number of frames correctly transmitted by the meter 1 to said data concentrator over a predefined duration, usually 24 hours, which enables the meter 1 to know the frame exchange success rate, which is a good indicator of the quality of the PLC communication.

[0079] The meter 1 is thus able to select the optimization phase, which itself will make it possible to communicate in the PLC with the best possible quality.

[0080] The meter 1 is also adapted by changing the phase to which the communication module 5 is coupled, in particular according to the topology of the network, then for example the addition of a new meter on the cluster.

[0081] Reference is made to Figure 3 The method for selecting the optimization phase according to the first embodiment is now described.

[0082] The selection method comprises test and connection steps.

[0083] In a first embodiment of the selection method, these test and connection steps are performed at regular intervals, for example every day, and comprise performing a scan of the three phases 3 in order to select the one associated with the best quality parameter, then connecting the communication module 5 to the selected phase.

[0084] During the test and connection steps, the microcontroller 7 controls the switching circuit 10 so that it successively connects the communication module 5 to each phase 3. Then, for each phase 3, when the communication module 5 is connected to said phase 3, the microcontroller 7 evaluates or acquires the quality parameter. The microcontroller 7 thus selects the phase for which the quality parameter is the greatest as the optimization phase, and controls the switching circuit 10 so that it connects the communication module 5 to said optimization phase.

[0085] For example, the quality parameter used is considered to be the SNR.

[0086] The selection method starts at time TO (step E0).

[0087] The microcontroller 7 selects phase 3a (step E1), i.e. it controls the switching circuit 10 to enable the transmission of the PLC signal between the input and output terminals of the cell circuit 11a associated with phase 3a, and it prevents such transmission for the other cell circuits 11b, 11c.

[0088] The microcontroller 7 thus evaluates or acquires the SNR (step E2).

[0089] Then, the microcontroller 7 selects phase 3b (step E3) and thus evaluates or acquires the SNR (step E4).

[0090] Then, the microcontroller 7 selects phase 3c (step E5) and thus evaluates or acquires the SNR (step E6).

[0091] The microcontroller 7 thus verifies whether the maximum value of the SNR is the SNR value obtained for phase 3a (step E7).

[0092] If this is the case, the microcontroller 7 selects phase 3a, which is thus the optimal phase to which the communication module 5 is connected for the next 24 hours (step E8). The microcontroller 7 thus waits for a duration Ti = 24 hours, then the method returns to step E1.

[0093] In step E7, if the maximum value of the SNR is not the SNR value obtained for phase 3a, the microcontroller 7 verifies whether the maximum value of the SNR is the SNR value obtained for phase 3b (step E9).

[0094] If this is the case, the microcontroller 7 selects phase 3b, which is thus the optimal phase to which the communication module 5 is connected for the next 24 hours (step E10). The microcontroller 7 thus waits for a duration Ti = 24 hours, then the method returns to step E1.

[0095] In step E9, if the maximum value of the SNR is not the SNR value obtained for phase 3b, the microcontroller 7 selects phase 3c, which is thus the optimal phase to which the communication module 5 is connected for the next 24 hours (step E11). The microcontroller 7 thus waits for a duration Ti = 24 hours, then the method returns to step E1.

[0096] In the second embodiment, with reference to Figure 4 the test and connection steps are only performed when the quality of the communication is not satisfactory.

[0097] When the communication module 5 is connected to a current phase, the microcontroller 7 evaluates or acquires the quality parameter. When the quality parameter becomes less than a predefined threshold, the microcontroller 7 performs the test and connection steps to select the optimal phase (which will initially be a different phase from the current phase).

[0098] The method assumes that during installation of the meter 1 (or during initialization of the program, the optimal phase is chosen by default, thus making it possible to implement the application).

[0099] The current phase is therefore considered to be phase 3a: the selected phase is phase 3a (step E100).

[0100] The microcontroller 7 therefore evaluates or acquires the SNR (step E101).

[0101] The microcontroller 7 compares the SNR with a predefined threshold value (for example, equal to 3 dB): step E102.

[0102] If the SNR is greater than or equal to the predefined threshold value, the method returns to step E100.

[0103] If the SNR is less than the predefined threshold value, the microcontroller 7 begins the test and connection steps.

[0104] The microcontroller 7 first selects phase 3a (step E103) and therefore evaluates or acquires the SNR (step E104).

[0105] The microcontroller 7 then selects phase 3b (step E105) and therefore evaluates or acquires the SNR (step E106).

[0106] The microcontroller 7 then selects phase 3c (step E107) and therefore evaluates or acquires the SNR (step E108).

[0107] The microcontroller 7 therefore verifies whether the maximum value of the SNR is the SNR value obtained for phase 3a (step E109).

[0108] If this is the case, the microcontroller 7 selects phase 3a, which is the optimal phase to which the communication module 5 is therefore connected (step E100). The microcontroller 7 therefore waits for a duration T2 = 5 hours, after which the method returns to step E101.

[0109] In step E109, if the maximum value of the SNR is not the SNR value obtained for phase 3a, the microcontroller 7 therefore verifies whether the maximum value of the SNR is the SNR value obtained for phase 3b (step E110).

[0110] If this is the case, the microcontroller 7 selects phase 3b, which is the optimal phase to which the communication module 5 is therefore connected (step E111). The microcontroller therefore waits for a duration T2 = 5 hours, after which the method moves to step E112.

[0111] In step E112, the microcontroller 7 evaluates or acquires the SNR.

[0112] The microcontroller 7 compares the SNR with a predefined threshold (step E113).

[0113] If the SNR is greater than or equal to the predefined threshold, the method returns to step E111.

[0114] If the SNR is less than the predefined threshold, the microcontroller 7 starts the test and connection steps (E103 to E110).

[0115] In step E110, if the maximum of the SNR is not the SNR value obtained for phase 3b, the microcontroller 7 selects phase 3c, which is thus the optimized phase to which the communication module 5 is connected (step E114). The microcontroller 7 thus waits for a duration T2=5 hours, then the method moves to step E115.

[0116] In step E115, the microcontroller 7 evaluates or acquires the SNR.

[0117] The microcontroller 7 compares the SNR with a predefined threshold (step E116).

[0118] If the SNR is greater than or equal to the predefined threshold, the method returns to step E114.

[0119] If the SNR is less than the predefined threshold, the microcontroller 7 starts the test and connection steps (E103 to E110).

[0120] The predetermined duration T2 makes it possible to maintain the stability of the network topology. Indeed, it is necessary to avoid changing the coupling phase too frequently. After each change of coupling phase, a duration of several hours must be respected before restarting the scanning of the phases.

[0121] Note that if the quality parameter used is not the SNR, but the LQI, the predefined threshold is for example equal to 52.

[0122] Thus, in the embodiment just described, the microcontroller 7 of the meter 1 evaluates the quality of the PLC communication and selects the optimized phase as a function of the result of this evaluation.

[0123] However, it is possible for the selection of the optimized phase to be carried out by an external entity, outside the meter 1.

[0124] This external entity is for example a server of the IS or a data concentrator, and is connected to a plurality of meters.

[0125] The external entity acquires the values of the quality parameter associated with all these meters, and itself determines for each meter 1 the optimized phase to be selected.

[0126] In this case, the microcontroller 7 of each meter 1 receives a selection command transmitted by the server of the IS, extracts from the selection command the identifier of the optimal phase that has been selected by the server of the IS, and controls the switching circuit 10 to connect the communication module 5 to said optimal phase.

[0127] With respect to the previous solution, this solution has the following advantages.

[0128] If the selection is performed by the meters 1 themselves, during the test and connection steps that have been described, one or more other meters themselves also start the test and connection steps, which can modify the selection result of the meter 1.

[0129] Therefore, the cluster of meters can require a considerable time to stabilize.

[0130] However, if the selection is performed by an external entity in a global and centralized manner, this external entity can order the connection operations, which shortens the stabilization time.

[0131] However, it should be noted that if the selection is performed at each meter, this selection can be more stable and can lead to a permanent stabilization.

[0132] Naturally, the present application is not limited to the described embodiments, but encompasses any variant falling within the scope of the present application as defined by the claims.

[0133] The quality parameters used are not necessarily systematically the same. Each meter can dynamically select the best parameter to use (for example, the value giving the greatest distance from a predefined threshold).

[0134] The quality parameters can also be dynamically selected by an entity centralized on the basis of observations made on a plurality of meters.

[0135] It is also possible to use several quality parameters, to confirm the selection result of the optimal phase, or to produce a combined parameter from several quality parameters. For example, the combined parameter is obtained by a weighted average of the quality parameters.

Claims

1. An electricity meter (1) arranged to measure the electrical energy supplied to a facility by a distribution network (2) comprising a plurality of phases (3), the electricity meter comprising: a communication module (5) arranged to enable communication by power line communication; a switching circuit (10) arranged to selectively connect the communication module (5) to one of the phases; a processor unit (6) arranged to control the switching circuit to connect the communication module to an optimized phase among the phases (3), the optimized phase being dynamically selected to optimize the quality of the communication by power line communication.

2. The electric meter of claim 1, wherein, The processor unit (6) is arranged to evaluate the quality of the communication by power line communication when the communication module (5) is connected to each phase (3), and to select the optimized phase as a function of the results of the evaluations.

3. The electric meter of claim 2, wherein, The quality of the communication by power line communication is evaluated as a function of at least one quality parameter comprising a signal-to-noise level and / or a frame exchange success rate.

4. The electricity meter of claim 3, wherein The signal-to-noise level is coded between 0 and 255 when PLC G3 technology is used to enable the communication by power line communication, and wherein the signal-to-noise level is evaluated in dB when PLC PRIME technology is used to enable the communication by power line communication.

5. The electricity meter of claim 3 or 4, wherein, The processor unit (6) is arranged to implement the following test and connection steps: control the switching circuit (10) so that it successively connects the communication module (5) to each phase (3); for each phase (3), evaluate or acquire the quality parameter when the communication module (5) is connected to the phase (3); select the phase for which the quality parameter is the greatest as the optimized phase, and control the switching circuit (10) so that it connects the communication module (5) to the optimized phase.

6. The electricity meter of claim 5 wherein, The processor unit (6) is arranged to implement the test and connection steps at regular intervals.

7. The electric meter of claim 5, wherein, The processor unit (6) is arranged to: evaluate or acquire the quality parameter when the communication module (5) is connected to the current phase; implement the test and connection steps when the quality parameter becomes less than a predefined threshold.

8. The electric meter of claim 1, wherein, The processor unit (6) is arranged to receive a selection command transmitted by an external entity, to extract from the selection command an identifier of the optimized phase that has been selected by the external entity, and to control the switching circuit (10) so as to connect the communication module (5) to the optimized phase.

9. The electricity meter of claim 1 wherein, The switching circuit (10) comprises, for each phase (3), a monolithic circuit (11) comprising: an input (E) connected to the communication module (5), and an output (S) connected to the phase; a switching element (12) comprising two transistors (13a, 13b) and arranged to selectively cut the connection between the input (E) and the output (S), or to enable the connection by passing the positive and negative alternations of a PLC signal emitted from or to the communication module (5); command circuit (16) arranged to receive a primary command signal (Scp) generated by said processor unit (6) and to generate a secondary command signal (Scs) to control said switching element (12).

10. A selection method implemented in the electric meter of claim 5 and comprising the following test and connection steps: controlling said switching circuit (10) so that it successively connects said communication module (5) to each phase (3); for each phase (3), when said communication module (5) is connected to said phase (3), evaluating or acquiring said quality parameter; selecting the phase with the greatest quality parameter as the optimal phase and controlling said switching circuit (10) so that it connects said communication module (5) to said optimal phase.

11. A computer program product comprising instructions for causing said processor unit (6) of the electric meter (1) of claim 5 to perform the steps of the selection method of claim 10.

12. A computer readable storage medium having stored thereon the computer program product of claim 11.

Images