Detection of cross connections on single-phase meter

Abstract

A single-phase electrical meter (1) comprising:-a phase conductor (8) intended to be connected to a phase line; -an electrical ground (10) connected to the phase conductor; -a floating potential target (17); -a processing unit (11) arranged to measure a target voltage (Vtarget) between the target and the phase conductor and to detect, as a function of the target voltage, a connection state of the phase and neutral lines on the meter (1), which connection state can be a normal connection or a cross connection.

Description

Technical Field

[0001] The invention relates to the field of single-phase electrical instruments. Background Art

[0002] Single-phase electrical meters are intended to measure the consumption by a facility of electrical energy supplied to the facility by a distribution network comprising phase and neutral conductors.

[0003] When installing the meter, the operator responsible for the installation may accidentally cross the connection of the phase and neutral wires on the meter. In this case, the neutral wire of the distribution network is connected to the upstream phase terminal of the meter, and the phase wire of the distribution network is connected to the upstream neutral terminal of the meter.

[0004] However, such cross-connections are a hazard to the user (subscriber), who expects the neutral line to be almost harmless and who may therefore handle the neutral line of his installation without knowing that it is actually connected to a phase line of the network.

[0005] This can also be a potential vector for fraud because, in the case of a cross connection, by connecting equipment between neutral and ground, it is possible to consume energy that the meter cannot measure.

[0006] Therefore, being able to automatically detect cross-connection faults between phase and neutral conductors on single-phase electrical meters seems particularly attractive.

[0007] However, there is currently no effective method to detect such faults on single-phase meters.

[0008] In three-phase meters, detection of cross connection is accomplished by a simple criterion of checking voltage unbalance. However, such a criterion cannot be applied to single-phase meters.

[0009] Purpose of the Invention

[0010] The present invention is intended to effectively detect cross-connections between phase and neutral conductors on a single-phase electrical meter. Summary of the invention

[0011] To achieve this purpose, a single-phase electrical meter is proposed, intended to measure the consumption of electrical energy by an installation supplied by a distribution network comprising a phase line and a neutral line, the meter comprising:

[0012] - a phase conductor, which is intended to be connected to the phase line;

[0013] - an electrical ground connected to the phase conductor;

[0014] - floating potential target;

[0015] A processing unit is arranged to measure a target voltage between the target and the phase conductor, and detect the connection state of the phase and neutral lines of the meter according to the target voltage, which connection state can be a normal connection or a cross connection. When the connection is correctly made, the phase line of the network is connected to the phase conductor, and the target voltage is relatively high. On the contrary, when the connection is incorrectly made, it is the neutral line of the network that is connected to the phase conductor, and the target voltage is relatively low.

[0016] The integration of a floating potential target in the meter thus makes it possible to define this target voltage, the value of which makes it possible to detect the connection state of the phase and neutral conductors on the meter. This detection, which is done indirectly by capacitive coupling, is very effective.

[0017] Furthermore, the invention is very simple and inexpensive to implement, since only the target has to be integrated in the instrument.

[0018] Furthermore, a single-phase electrical meter (such as described above) is proposed, wherein the processing unit is arranged to compare the target voltage with a predetermined threshold value and to detect a cross connection when the target voltage is smaller than said predetermined threshold value.

[0019] Additionally, a single-phase electrical meter (such as described above) has been proposed wherein the target is a conductive surface formed on a circuit board and not connected to the ground plane of the circuit board.

[0020] Furthermore, a single-phase electrical meter (such as described above) is proposed, wherein the processing unit comprises a measuring component arranged to measure a target voltage, said measuring component being mounted on said circuit board.

[0021] Furthermore, a single-phase electrical meter (such as described above) is proposed, wherein the processing unit is arranged to detect the presence of a person in the vicinity of the meter and to perform the detection of the connection status when the person is in the vicinity of the meter.

[0022] Furthermore, a single-phase electrical meter (such as described above) is proposed, wherein the meter comprises a housing, the housing comprising a button, the processing unit being arranged to detect the presence of a person in the vicinity of the meter when it detects a pressing of the button.

[0023] Furthermore, a single-phase electrical meter (such as described above) is proposed, wherein the meter comprises a housing including a test surface located on an outer surface of the housing, the processing unit being arranged to:

[0024] obtaining information based on which a procedure for manually checking the connection is initiated, the procedure including the steps of positioning a hand or finger of an individual on a test surface;

[0025] From this information it is inferred that the individual is located in the vicinity of the meter.

[0026] Furthermore, a single-phase electrical meter (such as described above) is proposed, the processing unit being arranged to perform a detection of the connection status each time the meter is switched on.

[0027] In addition, a detection method is proposed, which is implemented in a processing unit of a single-phase electrical meter (such as the one described above), and the method comprises the following steps:

[0028] - measuring the target voltage between the target and the phase conductor;

[0029] - Detecting the connection status of the phase line and the neutral line on the meter according to the target voltage, which connection status can be normal connection or cross connection.

[0030] In addition, a detection method (such as described above) is proposed, which is implemented in a processing unit of a single-phase electrical meter (such as described above), and the method includes the following steps: detecting the presence of a person near the meter, and performing a detection of the connection status when the person is near the meter.

[0031] In addition, a detection method (such as described above) is proposed, wherein the detection of the connection status comprises the following steps:

[0032] A normal connection is detected if the target voltage remains greater than a predetermined threshold for a first predetermined duration;

[0033] If the target voltage remains less than the predetermined threshold for a second predetermined duration, a cross connection is detected.

[0034] Furthermore, a detection method (such as described above) is proposed, which is implemented in a processing unit of a single-phase electrical meter (such as described above), the method comprising the following steps: performing a detection of the connection status each time the meter is switched on.

[0035] Additionally, a detection method (such as described above) is proposed, the method comprising the following steps:

[0036] If the target voltage remains greater than the predetermined threshold for a third predetermined duration, a normal connection is detected;

[0037] If the target voltage remains less than the predetermined threshold for a fourth predetermined duration, a cross connection is detected.

[0038] Furthermore, a computer program is proposed comprising instructions causing a processing unit of an instrument (such as described above) to execute the steps of a detection method (such as described above).

[0039] In addition, there is proposed a computer-readable recording medium having stored thereon a computer program (such as described above).

[0040] The present invention will be best understood from the following description of specific non-limiting embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Reference will be made to the accompanying drawings, in which:

[0042] [ Figure 1 ] Figure 1 Represents a distribution network and a single-phase electrical meter when the phase and neutral conductors are correctly connected;

[0043] [ Figure 2 ] Figure 2 When the phase and neutral lines cross, Figure 1 the accompanying drawings;

[0044] [ Figure 3 ] Figure 3 Detailed description of the steps of the detection method according to the first embodiment;

[0045] [ Figure 4 ] Figure 4 1 and 2 show the steps of the detection method according to the second embodiment. DETAILED DESCRIPTION

[0046] Reference Figure 1 and 2 , a single-phase electrical meter 1 is intended to measure the electrical energy consumption of a user (subscriber)'s installation 2. Electrical energy is supplied to the installation 2 by a distribution network 3.

[0047] The power distribution network 3 is a single-phase network and comprises a phase line Ph and a neutral line Ne.

[0048] The distribution of energy is performed equally according to the TT or TN system.

[0049] In this case, the network 3 comprises a distribution substation 4 to which the installations 2 and the meters 1 are connected via a phase line Ph and a neutral line Ne. The distribution substation 4 is a MT / BT substation.

[0050] The supplied voltage is an AC voltage with an effective voltage of 230 V in this case.

[0051] The user's installation 2 and the meter 1 are located in the user's residence and therefore in a space bounded by a wall 5. The installation 2 is in this case represented by an impedance Z charge Expressed electrically.

[0052] The meter 1 comprises a housing 7 including an upstream phase terminal P, an upstream neutral terminal N, a downstream phase terminal P′ and a downstream neutral terminal N′. In this case, by “upstream” is meant the network 3 side and by “downstream” is meant the installation 2 side.

[0053] The meter 1 comprises a phase conductor 8 and a neutral conductor 9 .

[0054] The phase conductor 8 is connected to the upstream phase terminal P and thus to the phase line Ph of the distribution network 3 upstream of the meter 1. The phase conductor 9 is connected to the upstream neutral terminal N and thus to the neutral line Ne of the distribution network 3 upstream of the meter 1. The downstream phase terminal P' and the downstream neutral terminal N' are connected to the installation 2.

[0055] The phase conductor 8 is connected to an electrical ground 10 of the meter 1 .

[0056] The meter 1 further comprises a processing unit 11 .

[0057] The processing unit 11 comprises at least one processing component 12, which is, for example, a "general purpose" processor, a processor dedicated to signal processing (or a DSP (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 processing component 12 is in this case a microcontroller.

[0058] The processing unit 11 also includes one or more memories 14 connected to or integrated in the microcontroller 12. At least one of these memories 14 forms a computer-readable recording medium on which is recorded at least one computer program including instructions that cause the microcontroller 12 to execute at least some of the steps of the detection method to be described below.

[0059] The processing unit 11 also includes a measurement component. The measurement component includes an analog-to-digital converter (ADC) 15, which produces digital measurements of the following: a voltage representing the voltage present on the phase line Ph, a voltage representing the voltage present on the neutral line Ne, and a voltage representing the current circulating on the phase line Ph. These measurements are conventionally used by the meter 1 to evaluate the power consumption of the installation 2 (metering).

[0060] The components of the processing unit 11 are in this case mounted on the same circuit board.

[0061] The voltage reference of the ADC 15 is the ground plane of the circuit board 16. The mass plane is connected to the electrical ground 10 and thus to the upstream phase terminal P.

[0062] The meter 1 also comprises a floating potential target 17 (ie a conductive element) which is not connected to any element having a fixed potential.

[0063] The ADC 15 comprises an input 18 connected to the target 17. The ADC 15 therefore also produces a measure of the potential difference between the target 17 and the electrical ground 10 (and therefore between the target 17 and the upstream phase terminal P of the meter 1).

[0064] Microcontroller 12 acquires and analyzes the digital measurements produced by ADC 15 .

[0065] exist Figure 1 , the connection of meter 1 has been correctly completed by the operator in the following way: the phase line Ph of network 3 is connected to the upstream phase line terminal P of meter 1 (and therefore to the phase conductor 8), and the neutral line Ne of network 3 is connected to the upstream neutral line terminal N of meter 1 (and therefore to the neutral conductor 9).

[0066] However, in Figure 2 , the operator has performed a cross-connection: the phase line Ph of the network 3 is connected to the upstream neutral line terminal N of the meter 1 (and therefore to the neutral conductor 9), and the neutral line Ne of the network 3 is connected to the upstream phase line terminal P of the meter 1 (and therefore to the phase conductor 8).

[0067] The present invention aims to detect the connection status of the phase line Ph and the neutral line Ne on the meter 1: the connection status can be a normal connection or a cross connection.

[0068] The principles of the present invention are described.

[0069] With a configuration such as proposed, the impedance is high between the target 17 and the ground plane of the plate 16. This impedance is mainly constituted by the parasitic capacitance between the target 17 and the ground plane (typically of the order of pF) and the input impedance of the measurement assembly (typically of the order of Mohm).

[0070] It can be seen that the target 17 is coupled to the ground line via a first capacitive coupling (permanently) and possibly also punctually via a second capacitive coupling.

[0071] The first coupling is a fixed ambient coupling (ie in this case via one of the walls 5a).

[0072] The second coupling is via a person (typically an operator or user) located in the vicinity of the meter 1, who is himself coupled to earth through the fixed environment, ie in this case via the floor and one of the walls 5b.

[0073] It is assumed that the person has approached the meter 1 with his hand 20 , or has even placed his hand 20 or a finger on the meter 1 .

[0074] This gives:

[0075] Z coupl_earth =Z coupl_wall / / (Z coupl_hand +Z body ),

[0076] in:

[0077] -Z coupl_earth is the resulting coupling impedance between the target 17 and the ground;

[0078] -Zcoupl_wall is the coupling impedance between the target 17 and the ground via the wall 5a (first coupling);

[0079] -Z coupl_hand is the coupling impedance between the target 17 and the individual's hand 20 (second coupling);

[0080] -Z body is the coupling impedance between the individual's body and the ground via the wall 5b and the floor (second coupling).

[0081] Naturally, if no person is located near the meter 1, the target 17 is coupled to the ground only via the wall 5a.

[0082] and:

[0083] Z coupl_earth =Z coupl_wall

[0084] Impedance to ground Z earth_distant The impedance (ie the impedance between the local earth of the meter 1 and the earth at the network voltage source (distribution substation 4)) is low (typically <100 Ohms).

[0085] Fixed environmental diversity will make the first coupling very variable (and sometimes very low). However, the second coupling will always be significant when an individual is close to the meter 1. This proximity of the individual's body can be done, for example, by their hand in the following ways: involuntarily during the use of the button 21 of the meter 1, or voluntarily during the explicit detection phase by placing the hand on the surface 22 of the housing 7 of the meter 1 provided for this purpose.

[0086] When the wiring is done correctly (such as in Figure 1 In the case of ), a target voltage V is established between the target 17 and the ground plane (and therefore, the phase conductor 8). target Given by:

[0087] V target =V network x Z target / (Z target +Z coupl_earth +Z earth_distant +Z earth_connection +(Z line_P / /

[0088] (Z line_N +Z charge )))

[0089] We have:

[0090] Z earth_distant +Z earth_connection +Z line_P < <Zcoupl_earth

[0091] Z earth_distant +Z earth_connection +Z line_P < <Z target

[0092] Z lineP < <Z charge

[0093] The above formula can therefore be rewritten in the following simplified form:

[0094] V target =V network x Z target / (Z target +Z coupl_earth )

[0095] It is observed that when the wiring is done correctly, a significant voltage is then established on the target 17 because Z target The order of magnitude is greater than or similar to Z coupl_earth .

[0096] The target 17 is located inside the housing 7, since the detection principle is effected contactlessly.

[0097] The target 17 is in this case a conductive surface (target field) which is formed on the circuit board 16 and is not connected to the ground plane of said circuit board 16 .

[0098] The target 17 is, for example, a square conductive surface of 5 mm x 5 mm.

[0099] In the case where the coupling is assumed to be linear, the target voltage must therefore be a sinusoid of the same frequency and with an amplitude that depends on the strength of the target-ground coupling. In order for this amplitude to be relatively high and therefore easily measurable, it is preferred that the impedance of the target-ground coupling (either by a fixed environment or by the user's hand) has an order of magnitude similar to or greater than the target-phase impedance (typically constituted by the input impedance of the ADC 15 and the parasitic coupling between the target 17 and the ground plane of the meter 1 connected to its upstream phase terminal P).

[0100] exist Figure 2 In the cross-connection case shown in FIG, the target voltage V target tends to zero. In fact, in this configuration, the target voltage V target is expressed as follows:

[0101] V target =[V network / (1+(Z charge +Z line_P ) / Z line_N )]x Z target / (Ztarget +Z coupl_earth +

[0102] Z earth_distant +Z earth_connection +(Z line_P / / (Z line_N +Z charge )))

[0103] And because Z charge >>Z line_N , so the first part of the expression tends to 0.

[0104] Therefore, it is observed that when the connection has been made correctly, the target voltage V target Significantly greater than the target voltage V in the case of cross-connection target .

[0105] The processing unit 11 thus measures the target voltage V between the target 17 and the phase conductor 8 target , and according to the target voltage V target To detect the connection status of the phase line Ph and the neutral line Ne on the meter 1. The connection status can be normal connection or cross connection.

[0106] The processing unit 11 converts the target voltage V target is compared with a predetermined threshold value, and at the target voltage V target When the target voltage is less than the predetermined threshold, a cross connection is detected. In this case, the amplitude of the effective value of the target voltage is compared with the predetermined threshold.

[0107] Predetermined threshold V threshold The specific value depends on the size of the target 17 .

[0108] In the example of setting the size of the target 17 described above, the predetermined threshold value V threshold For example, equal to 150mV.

[0109] For example, the target voltage V target It is the effective value (RMS (root mean square) voltage) calculated over an integration window of duration equal to, for example, 1 second.

[0110] The target voltage actually existing on the target 17 and measured via the ADC 15 is an alternating voltage with a frequency equal to 50 Hz (or 60 Hz).

[0111] Filtering may be implemented to filter out higher frequency noise from destructive sources that could tend to bias the measurements (the "high impedance" nature and optional remoteness from the target makes it potentially susceptible to noise sources).

[0112] The filtering is preferably digital filtering. Thus, the filter used is, for example, a 2nd order digital filter with a bandwidth of 50 Hz.

[0113] Analog filters can also be used.

[0114] In this case, the filter is implemented in the processing unit 11 .

[0115] Now refer to Figure 3 A first embodiment of the detection method is described, which is implemented in the processing unit 11 .

[0116] The method thus comprises monitoring the target voltage V target And instantaneous detection is performed at approximately the moment coupling with the user is ensured.

[0117] In this case, measuring the target voltage is done continuously, as long as the meter 1 is turned on. The detection of the connection state (i.e. the comparison with the predetermined threshold value and the analysis of the result) is done each time the processing unit 11 detects the presence of a user (or another person) in the vicinity of the meter 1. Alternatively, measuring the target voltage V target It may only start when the presence of a user is detected.

[0118] The processing unit 11 can detect the presence of a user near the meter 1 when it detects the pressing of the button 21. In fact, when the pressing of the button 21 of the meter 1 is performed, this must mean that a person is located near the meter 1. The button 21 is any button of the meter 1 which is not originally (but can be) dedicated to this function.

[0119] The processing unit 11 can also use the test surface 22. This test surface makes it possible to perform a procedure for manually detecting the connection status. The user informs the meter 1 and the processing unit 11 when he wants to start this manual procedure. He communicates with the meter 1 for this via any interface: a button on the meter 1, by using his smartphone, etc. This manual procedure requires the user to position his hand or finger on the test surface 22, which is located on the outer surface of the housing 7, while being located near the target 17.

[0120] The processing unit 11 thus acquires information from which it initiates a procedure for manually checking the connection, said procedure comprising the step of positioning the hand or finger of the individual on the test surface 22. The processing unit 11 infers from this information that the individual is located in the vicinity of the meter 1 .

[0121] After detecting the presence of the person in the vicinity of the meter 1 , the method begins with an initial step: step E1 .

[0122] If the connection state is not an unknown connection state, the method moves to step E2 and ends.

[0123] If the connection state is an unknown connection state, the processing unit 11 analyzes the target voltage V target :Step E3.

[0124] If the target voltage is greater than a predetermined threshold (in this case strictly greater than), the method moves to step E4.

[0125] In step E4, if the target voltage V target If it remains greater than this predetermined threshold for (at least) a first predetermined duration T1 , the processing unit 11 detects the user's hand and therefore detects a normal connection on the meter 1 : step E5 .

[0126] The first predetermined duration T1 is a very short (programmable) time threshold, typically equal to a few seconds.

[0127] The method thus ends in: step E2.

[0128] In step E4 , if the target voltage becomes less than (in this case less than or equal to) the predetermined threshold value before the end of the first predetermined duration T1 , the method returns to step E3 .

[0129] In step E3, if the target voltage remains less than (in this case less than or equal to) the predetermined threshold for (at least) a second predetermined duration T2, the processing unit 11 has not detected the user's hand and therefore detects a cross connection: step E6.

[0130] The second predetermined duration T2 is a very short (programmable) time threshold, typically equal to a few seconds.

[0131] The processing unit 11 thus transmits an alarm to the central system, ie to the energy distributor and / or the network manager: step E7. This alarm is usually issued via power line communication (for example according to the protocol CPL-G3) or via radio communication (for example via the LTE-M network or according to the protocol NB-IoT).

[0132] An alarm message intended for the user is also displayed on the screen of the meter 1. The operator in charge of installing the meter 1 can also observe his error due to the alarm message and correct it immediately.

[0133] The method thus ends in: step E2.

[0134] Now refer to Figure 4 A second embodiment of the detection method is described, which is implemented in the processing unit 11 .

[0135] This embodiment includes monitoring the target voltage V target and looking for long coherent periods of signal absence to detect the body.

[0136] In this case, the target voltage V is measured target And the detection of the connection status (ie the comparison with the predetermined threshold value) is done continuously as long as the meter 1 is switched on.

[0137] Assuming that the connection of the meter 1 must be completed when switched off, the detection method is triggered each time the power is switched on to check whether the wiring direction was correct during the initial installation or has not been modified during the last switch-off. The initial state of the connection state is therefore an unknown state at the start of the method: step E10.

[0138] The processing unit 11 analyzes the target voltage V target :Step E11.

[0139] If the target voltage is greater than a predetermined threshold (in this case strictly greater than), the method moves to step E12.

[0140] In step E12 , if the target voltage remains greater than the predetermined threshold for (at least) a third predetermined duration T3 , the processing unit 11 detects the presence of a body and therefore a normal connection on the meter 1 : step E13 .

[0141] The third predetermined duration T3 is a relatively short (programmable) time threshold to avoid false positives, typically equal to ten seconds.

[0142] The method thus ends in step E14 .

[0143] In step E12 , if the target voltage becomes lower than (in this case lower than or equal to) the predetermined threshold value before the end of the third predetermined duration T3 , the method returns to step E11 .

[0144] In step E11 , if the target voltage remains less than (in this case less than or equal to) the predetermined threshold value for (at least) a fourth predetermined duration T4 , the processing unit 11 detects no soma and therefore a cross-connection: step E15 .

[0145] The fourth predetermined duration T4 is a relatively long (programmable) time threshold to avoid false positives, typically equal to one hour.

[0146] The processing unit 11 thus transmits an alarm to the central system, ie to the energy distributor and / or the network manager: step E16. This alarm is usually issued via power line communication (for example according to the protocol CPL-G3) or via radio communication (for example via an LTE-M network or according to the protocol NB-IoT).

[0147] An alarm message intended for the user is also displayed on the screen of the meter 1. The operator in charge of installing the meter 1 can also observe his error due to the alarm message and correct it immediately.

[0148] The method thus ends in step E14 .

[0149] Regardless of the embodiment of the detection method, it is foreseen that the method is disengageable: the energy distributor and / or the network manager and / or the user may decide to deactivate the functionality.

[0150] These two embodiments are naturally combinable. Thus, detection according to the second embodiment will be carried out every time the meter 1 is switched on, and detection according to the first embodiment will be carried out every time the processing unit 11 detects the presence of a person in the vicinity of the meter 1 .

[0151] Naturally, the invention is not limited to the embodiments described, but encompasses any variant coming within the field of the invention, such as those defined in the claims.

[0152] The target surface may have different shapes and sizes than those mentioned in this case. It may be positioned differently in the instrument (not necessarily on the circuit board).

[0153] In particular, the target can be moved above, below or to the side of the circuit board.

[0154] For example, the target is elevated so that it is located 1 cm from the ground plane of the circuit board.

[0155] The target is then, for example, positioned on a mechanical component (support) provided for this purpose to ensure that its position is well controlled and connected by wires to a circuit board (for measuring the voltage by an ADC), the size and positioning of the target being carefully ensured so that the coupling it provides to the ground plane of the circuit board remains negligible or at least is taken into account in the overall dimensioning.

[0156] Note that when the target is integrated directly on the circuit board, there is a distance relative to the ground plane, more typically around 1 mm. If the latter case leads to too much coupling with the ground plane of the board, one could consider "tailoring" the ground surface of the copper layers of the printed circuit that are opposite to the target and have, for example, a coupled rather than a coplanar type.

[0157] In practice, the geometrical solutions are multiple, depending on the surface of the target, its grounding relative to the circuit board and its positioning relative to the outer surface of the housing (whether it is remote or not).

[0158] To further improve target-ground coupling, excess thickness of solid material (e.g., and preferably plastic) can be used inside the housing and near the target to provide a dielectric constant significantly greater than air, which allows greater distances and / or capacitive coupling to be achieved than for the same gas-filled volume.

[0159] The detection of the presence of a person near the meter can be done differently and in particular thanks to any type of proximity sensor.

[0160] The architecture of the circuit board and the components used can be different. For example, the amplification and protection stage can be integrated into the acquisition component of the target voltage, including, for example, an operational amplifier. The components of the processing unit do not necessarily all have to be mounted on the same circuit board.

Claims

1. A single-phase electrical meter (1) intended to measure the consumption of electrical energy by an installation (2) supplied by a distribution network (3) comprising a phase conductor (Ph) and a neutral conductor (Ne), said meter include: a phase conductor (8) intended to be connected to the phase line; an electrical ground (10) connected to the phase conductor; A floating potential target (17); A processing unit (11) is arranged to measure a target voltage (V target ), and detects the connection status of the phase line and the neutral line on the meter (1) according to the target voltage, and the connection status can be a normal connection or a cross connection.

2. A single-phase electrical meter according to claim 1, wherein the processing unit is arranged to compare the target voltage with a predetermined threshold value and to detect the cross connection when the target voltage is less than the predetermined threshold value.

3. A single-phase electrical meter according to any one of the preceding claims, wherein the target (17) is a conductive surface formed on a circuit board (16) and not connected to a ground plane of the circuit board.

4. A single-phase electrical meter according to claim 3, wherein the processing unit (11) comprises a measuring component (15) arranged to measure the target voltage, the measuring component being mounted on the circuit board.

5. Single-phase electrical meter according to one of the preceding claims, the processing unit (11) being arranged to detect the presence of a person in the vicinity of the meter and to perform the detection of the connection state when the person is in the vicinity of the meter (1).

6. A single-phase electrical meter as claimed in claim 5, wherein the meter (1) comprises a housing (7), the housing (7) comprising a button (21), the processing unit (11) being arranged to detect the presence of the person in the vicinity of the meter when it detects a pressing of the button.

7. A single-phase electrical meter according to any one of claims 5 or 6, wherein the meter comprises a housing (7), the housing (7) comprising a test surface (22) located on an outer surface of the housing (7), the processing unit being arranged to: obtaining information based on which a procedure for manually checking a connection is initiated, the procedure including the step of positioning a hand or finger of the individual on the test surface (22); From said information it is inferred that said individual is located in the vicinity of said meter (1).

8. Single-phase electrical meter according to one of the preceding claims, the processing unit (11) being arranged to perform a detection of the connection status each time the meter is switched on.

9. A detection method, implemented in the processing unit (11) of the single-phase electrical meter (1) according to one of the preceding claims, and The following steps are involved: The target voltage (V target ); The connection status of the phase line and the neutral line on the meter (1) is detected according to the target voltage, and the connection status can be a normal connection or a cross connection.

10. The detection method according to claim 9, wherein the detection method is implemented in the processing unit (11) of the single-phase electrical meter (1) according to claim 5, wherein the detection method The following steps are involved: The presence of a person near the meter is detected, and the detection of the connection status is performed when the person is near the meter.

11. The detection method according to claim 10, wherein the detection of the connection status The following steps are involved: If the target voltage remains greater than a predetermined threshold for a first predetermined duration (T 1 ), a normal connection is detected; If the target voltage remains less than the predetermined threshold for a second predetermined duration (T 2 ), a cross connection is detected.

12. The detection method according to any one of claims 9 to 11, implemented in the processing unit (11) of the single-phase electrical meter according to claim 8, comprising a step of performing a detection of the connection status each time the meter is turned on.

13. The detection method according to claim 12, The following steps are involved: If the target voltage remains greater than the predetermined threshold for a third predetermined duration (T 3 ), a normal connection is detected; If the target voltage remains less than the predetermined threshold for a fourth predetermined duration (T 4 ), a cross connection is detected.

14. A computer-readable recording medium having instructions recorded thereon, the instructions causing the processing unit (11) of the meter (1) according to claim 1 to execute the steps of the detection method according to claim 9.

Images