Estimation of power consumed on phase despite fraud

Abstract

A power estimation method implemented in a three-phase electricity meter (1), and the method includes the following steps: detecting fraud that tampered with a first voltage measurement on a first phase (Ph1); obtaining a second voltage measurement on a second phase (Ph2), the second voltage measurement not tampered with by the fraud; estimating a first phase shift between the first phase voltage (V1) and a first phase current (I1) by using a first phase shift estimate between the first phase voltage (V1) and the second phase voltage (V2); estimating at least one first electric power consumed on the first phase from the first current measurement on the first phase, the second voltage measurement, and the first phase shift.

Description

Technical Field

[0001] The present invention relates to the field of three-phase electricity meters. Background Art

[0002] Electricity meters used in industrial applications often measure power and energy distributed via very high current levels, often up to 2000 A. These meters are typically three-phase meters.

[0003] This instrument includes current input and voltage input.

[0004] Current sensors, such as Rogowski sensors or external current transformers, are usually installed on the phases. Each current sensor is connected to the current input via two wires. Thus, for each phase, the instrument acquires an image of the current circulating on said phase.

[0005] Each voltage input is typically connected to a phase by a wire. Thus, the meter has direct access to the voltage on each phase via the associated wire.

[0006] Known fraud involves cutting one or more of the wires connecting the phases to the voltage input terminals. The purpose of this type of fraud is to underestimate the total energy consumption measured by the meter in order to reduce the bill paid to the electrical energy distributor.

[0007] In the event of fraud, the prior art meter continues to make metering measurements on the three phases without taking into account the fraud and therefore actually underestimates the energy consumed. Even if fraud is detected, the distributor does not know the actual energy consumed by the fraudster's facility. However, it can prove useful to know the actual energy consumed, for example to recover payment for unbilled energy from the fraudster (in addition to possible penalties, intended to sanction the fraud attempt). Summary of the invention

[0008] The present invention aims to estimate the total energy consumed by a facility despite the presence of fraud including false voltage measurements on the phases.

[0009] In view of achieving this goal, a power estimation method is proposed, which is implemented in a three-phase electricity meter connected to three phases of a distribution network and includes the following steps:

[0010] detecting fraud that tampers with at least one first voltage measurement, an image of a first phase voltage present on a first phase;

[0011] acquiring at least one second voltage measurement, an image of a second phase voltage present on a second phase, the at least one second voltage measurement not fraudulently tampered with;

[0012] estimating a first phase shift between a first phase voltage and a first phase current circulating on the first phase by using a first phase shift estimate that is a theoretical estimate of an expected phase shift between the first phase voltage and the second phase voltage in the absence of fraud;

[0013] At least one first electrical power consumed on the first phase is estimated from the at least one first current measurement, the image of the first phase current, the image of the at least one second voltage measurement, and the image of the first phase shift.

[0014] When fraud is detected on the first phase, the first phase voltage measurement is tampered with and therefore cannot be used. The power estimation method according to the invention therefore estimates the first electric power using in particular the second voltage measurement on the second phase and a theoretical estimate of the first phase shift between the first phase voltage and the first phase current. Thus, despite the presence of fraud, the energy distributor is able to obtain a relatively accurate estimate of the total electricity and the total energy actually consumed by the facility.

[0015] In addition, such as described above, a power estimation method is proposed in which a first phase shift is estimated from a phase shift between a second phase voltage and a second phase current circulating on a second phase, a phase difference between the second phase current and the first phase current, and a first phase shift estimate.

[0016] Additionally, a power estimation method such as above is proposed, wherein the first phase shift estimate is equal to +120° or -120°.

[0017] Furthermore, a power estimation method such as described above is proposed, wherein the at least one second voltage measurement comprises an effective value of the second phase voltage and / or a level of a fundamental frequency of the second phase voltage.

[0018] In addition, a power estimation method such as that described above is proposed, wherein at least one first electric power includes a first active power estimated from the effective value of the second phase voltage, the effective value of the first phase current, and the first phase shift; and / or a first reactive power estimated from the level at the fundamental frequency of the second phase voltage, the level at the fundamental frequency of the first phase current, and the first phase shift; and / or a first apparent power estimated from the effective value of the second phase voltage and the effective value of the first phase current.

[0019] Furthermore, a power estimation method such as described above is proposed, wherein fraud is detected when at least one first voltage measurement is smaller than a predefined voltage threshold and at least one first current measurement is larger than a predefined current threshold.

[0020] In addition, a power estimation method such as described above is proposed, which also includes the following steps: if the fraud also tampered with at least one third voltage measurement, the image of the third phase voltage present on the third phase, then at least one second voltage measurement is used again to estimate at least one third electrical power consumed on the third phase.

[0021] In addition, a power estimation method such as the one described above is proposed, further comprising the following steps:

[0022] acquiring at least one third voltage measurement, an image of a third phase voltage present on a third phase, the third voltage measurement not fraudulently tampered with;

[0023] An arithmetic mean of the at least one second voltage measurement and the at least one third voltage measurement is calculated to estimate at least one first electrical power.

[0024] In addition, a power estimation method such as described above is proposed, in which the first phase shift is obtained by calculating the arithmetic mean of the phase shift obtained by using the measurement of the second phase and the phase shift obtained by using the measurement of the third phase.

[0025] In addition, a power estimation method such as that described above is proposed, which also includes the following steps: detecting whether the distribution network includes or does not include a neutral line in addition to the three phases, and if this is not the case, correcting at least one second electric power consumed on the second phase, and if the fraud has not tampered with at least one third voltage measurement, the image of the third phase voltage present on the third phase, also correcting at least one third electric power consumed on the third phase.

[0026] In addition, a power estimation method such as that described above is proposed, wherein the correction includes: multiplying the at least one second electric power and the at least one third electric power by the same predetermined factor, and phase shifting at least one second electric power with a predefined second phase shift and at least one third electric power with a predefined third phase shift.

[0027] In addition, a power estimation method such as that described above is proposed, wherein the predetermined factor is equal to And wherein the predefined second phase shift is equal to -30°, and the predefined third phase shift is equal to +30°.

[0028] In addition, a power estimation method such as the one described above is proposed, wherein when the angle between the second phase voltage and the third phase voltage is The absence of neutral is detected when:

[0029]

[0030] X is a positive predefined value and is less than 30.

[0031] Furthermore, a three-phase electricity meter is proposed, comprising a processing component arranged to implement a power estimation method such as described above.

[0032] Furthermore, a three-phase electricity meter such as described above is proposed, further comprising a measurement component separate from the processing component and arranged to generate at least one first voltage measurement, at least one second voltage measurement and at least one first current measurement.

[0033] In addition, a computer program is proposed, comprising instructions for driving a processing component of a three-phase electricity meter such as described above to perform the steps of a power estimation method such as described above.

[0034] In addition, there is proposed a recording medium readable by a computer on which a computer program such as described above is recorded.

[0035] The present invention may be better understood in light of the following description of certain non-limiting embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] With reference to the accompanying drawings, in which:

[0037] [ Figure 1 ] Figure 1 A three-phase electricity meter in a four-wire configuration according to the present invention is shown;

[0038] [ Figure 2 ] Figure 2 A three-phase electricity meter in a three-wire configuration according to the present invention is shown;

[0039] [ Figure 3 ] Figure 3 represents the Fresnel diagram of the voltage and current measured on each phase in a four-wire configuration in a normal situation (on the left-hand side) and in a fraudulent situation (on the right-hand side);

[0040] [ Figure 4 ]1a Figure 4 is with Figure 3 A similar diagram but in a three-wire configuration;

[0041] [ Figure 5 ] Figure 5 is a flow chart showing the steps of a power estimation method according to the present invention. DETAILED DESCRIPTION

[0042] See also Figure 1 , the power estimation method according to the first embodiment of the invention is implemented in a three-phase electricity meter 1, which is intended to measure the electric energy supplied to a user's facility 2 through a distribution network 3. The facility 2 is an industrial facility.

[0043] In this case, this is a four-wire configuration.

[0044] Thus, the distribution network 3 comprises a first phase Ph1, a second phase Ph2, a third phase Ph3 and a neutral line N. A circuit breaker 4 is placed at the "border" between the distribution network 3 and the installation 2. The three phases Ph1, Ph2, Ph3 and the neutral line N enter the circuit breaker 4 and emerge from it towards the installation 2. The circuit breaker 4 enables the electrical energy distribution to be cut off.

[0045] The meter 1 comprises four voltage input terminals Ue1, Ue2, Ue3, UeN and three current input terminals Ie1, 1e2, Ie3 (each current input terminal comprises two ports).

[0046] The voltage input terminal Ue1 is connected to the first phase Ph1 through the wire f1, the voltage input terminal Ue2 is connected to the second phase Ph2 through the wire f2, the voltage input terminal Ue3 is connected to the third phase Ph3 through the wire f3, and the voltage input terminal UeN is connected to the neutral line N through the wire fN.

[0047] The current input terminal Ie1 is connected to the external current transformer CT1 installed on the first phase Ph1, the current input terminal 1e2 is connected to the external current transformer CT2 installed on the second phase Ph2, and the current input terminal Ie3 is connected to the external current transformer CT3 installed on the third phase Ph3. The external current transformer is located outside the meter 1.

[0048] In this case, each external current transformer has a transformation ratio equal to 2000.

[0049] In order to realize the metering measurement, the meter 1 collects the images of the phase currents I1, I2, I3 circulating on the phases Ph1, Ph2 and Ph3 at the current inputs Ie1, Ie2, Ie3 and due to the external transformers CT1, CT2 and CT3. The meter 1 also collects the phase voltages V1, V2, V3 present on the phases Ph1, Ph2, Ph3 and the neutral line voltage VN present on the neutral line N at the voltage inputs Ue1, Ue2, Ue3 and UeN.

[0050] The meter 1 further comprises a metering core which is a "fully integrated" measuring assembly 5. The measuring assembly 5 comprises inputs connected to the current inputs Ie1, Ie2, Ie3 and the voltage inputs Ue1, Ue2, Ue3, UeN and in particular integrates an input filter, an analog-to-digital converter, a digital calculation module, and a digital communication module for transmitting the digital measurements it performs.

[0051] The measuring assembly 5 generates a first voltage measurement, an image of the first phase voltage V1 present on the first phase Ph1, and a first current measurement, an image of the first phase current I1 circulating on the first phase Ph1. In particular, the measuring assembly 5 generates the following measurements (after calculations):

[0052] V1 RMS , which is the effective value of the first phase voltage V1;

[0053] VF1 RMS , which is the level of the fundamental frequency of the first phase voltage V1;

[0054] I1 RMS , which is the effective value of the first phase current I1;

[0055] IF1 RMS , which is the level of the fundamental frequency of the first phase current I1;

[0056] Likewise, the measurement assembly 5 generates a second voltage measurement and a second current measurement of the second phase Ph2. In particular, the measurement assembly 5 generates the following measurements (after calculation):

[0057] V2 RMS , VF2 RMS , I2 RMS , IF2 RMS .

[0058] Likewise, the measurement assembly 5 generates a third voltage measurement and a third current measurement of the third phase Ph3. In particular, the measurement assembly 5 generates the following measurements (after calculation):

[0059] V3 RMS , VF3 RMS , I3 RMS , IF3 RMS .

[0060] The measuring assembly 5 also produces, for each phase, a measure of the phase shift between the phase voltage and the phase current on said phase.The measuring assembly also produces a measure of the phase difference between two different phases and between the phase currents of two different phases.

[0061] Furthermore, the measuring assembly 5 calculates from these measurements and for each phase the active power, reactive power and apparent power consumed on said phase.Measurements of the energy consumed over time are derived from these power estimates.

[0062] The device 1 further comprises a processing component 6 .

[0063] The processing component 6 is adapted to execute the instructions of the program to implement the power estimation method according to the present invention. The program is stored in a memory 7, which is integrated in or connected to the processing component 6. The processing component 6 is, for example, a conventional processor, a microcontroller, a DSP (digital signal processor) or a programmable logic circuit, such as an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit).

[0064] In this case, the processing component 6 is a microcontroller.

[0065] The microcontroller 6 is connected to the measurement assembly 5 and acquires the measurements (as well as the calculation results and estimates) produced by the measurement assembly 5 .

[0066] It should be noted that the measurement assembly 5 operates as a “black box”: the microcontroller 6 can only access data produced by the measurement assembly 5 at the output, but not intermediate data processed in the measurement assembly 5. Furthermore, the only measurements accessible to the microcontroller 6 are those produced by the measurement assembly 5.

[0067] At regular intervals, the microcontroller 6 attempts to detect a fraudulent cutting of one of these conducting wires f1 , f2, f3. The microcontroller 6 detects the cutting of a conductor of a phase in the absence of voltage and in the presence of current on said phase.

[0068] For example, for the first phase Ph1 , the microcontroller 6 acquires at least one first voltage measurement and at least one first current measurement generated by the measuring component 5 and detects fraud when at least one first voltage measurement is less than a predefined voltage threshold and at least one first current measurement is greater than a predefined current threshold.

[0069] In this case, the microcontroller 6 detects fraud on the first phase Ph1 when:

[0070] V1 RMS <Vf

[0071] And I1 RMS >If,

[0072] Vf is a predefined voltage threshold and If is a predefined current threshold.

[0073] Advantageously, If is chosen such that:

[0074] Istart<If<Imin,

[0075] Istart is the current value at which the meter 1 starts measuring the consumed energy, and Imin is the current value at which the meter 1 must measure the current with nominal accuracy.

[0076] In this case, the following occurs: Istart=1 mA and Imin=10 mA.

[0077] Therefore, for example, If=5mA is selected. For example, Vf=40V is selected.

[0078] This fraud detection step is performed in the same way for the other two phases.

[0079] It is now assumed that the microcontroller 6 has detected fraud (only) on the first phase Ph1 .

[0080] The first voltage measurement is thus fraudulently tampered with. Therefore, the microcontroller 6 will estimate at least one first electric power consumed on the first phase Ph1 by using a voltage measurement on a reference phase that has not been subject to fraud. For example, this reference phase is the second phase Ph2. The microcontroller 6 thus acquires at least one second voltage measurement, an image of the second phase voltage V2 present on the second phase Ph2, which at least one second voltage measurement has not been fraudulently tampered with.

[0081] In this case, the microcontroller 6 acquires:

[0082] V2 RMS , VF2 RMS .

[0083] Furthermore, the microcontroller 6 must estimate a first phase shift between the first phase voltage V1 and the first phase current I1 circulating on the first phase Ph1 .

[0084] However, due to fraud, the phase shift information provided by the measuring assembly 5 for the first phase Ph1 is not valid.

[0085] The microcontroller 6 will therefore estimate the first phase shift by using a first phase shift estimate which is a theoretical estimate of the expected phase shift between the first phase voltage V1 (in this case whose measurement is not available) and the (reference) second phase voltage in the absence of fraud (i.e. under normal conditions).

[0086] In this case, the first phase shift is estimated to be equal to +120°.

[0087] More specifically, the first phase shift is estimated based on the phase shift between the second phase voltage V2 circulating on the second phase Ph2 and the second phase current I2 , the phase difference between the second phase current I2 and the first phase current I1 , and the first phase shift estimate.

[0088] The first phase shift between the first phase voltage V1 and the first phase current I1 (estimated by the microcontroller 6) is referred to as

[0089] Therefore, the following occurs:

[0090]

[0091] To obtain Microcontroller 6 calculates:

[0092]

[0093] The microcontroller 6 assimilates the following as:

[0094] (Phase of V1 - Phase of V2)

[0095] The first phase shift is estimated, which is +120°.

[0096] value:

[0097] (Phase of V2 - Phase of I2)

[0098] It is measured by the measuring component 5 (and acquired by the microcontroller 6 ).

[0099] value:

[0100] (Phase of I2 - Phase of I1)

[0101] It is measured by the measuring component 5 (and acquired by the microcontroller 6 ).

[0102] Therefore, the first phase shift is estimated particularly cleverly, not using measurements on the first phase Ph1, but by using non-tampered available measurements, and the first phase shift.

[0103] The microcontroller 6 also acquires at least one first current measurement, an image of the first phase current I1 circulating on the first phase Ph1 (the current measurement has not been tampered with, since the fraud affects only the first phase voltage measurement).

[0104] Thus, the microcontroller 6 estimates at least one first electrical power consumed on the first phase from the at least one first current measurement, the image of the first phase current I1 , the at least one second voltage measurement, and the first phase shift.

[0105] In this case, the microcontroller 6 calculates a first active power, a first reactive power, and a first apparent power consumed on the first phase Ph1 .

[0106] The first active power is estimated from the effective value of the second phase voltage V2, the effective value of the first phase current I1, and the first phase shift. The first reactive power is estimated from the level of the fundamental frequency of the second phase voltage V2, the level of the fundamental frequency of the first phase current I1, and the first phase shift. The first apparent power is estimated from the effective value of the second phase voltage V2 and the effective value of the first phase current I1.

[0107] The microcontroller 6 therefore calculates:

[0108]

[0109]

[0110] S1=V2 RMS .I1 RMS (First apparent power).

[0111] If the microcontroller 6 detects fraud, which tampers with at least one first voltage measurement, the image of the first phase voltage V1 present on the first phase Ph1, and also tampers with at least one third voltage measurement, the image of the third phase voltage V3 present on the third phase Ph3, the microcontroller 6 again uses the second phase Ph2 as a reference phase for estimating both the first electrical power consumed on the first phase Ph1 and the third electrical power consumed on the third phase Ph3.

[0112] The microcontroller 6 therefore calculates (as described above):

[0113]

[0114]

[0115] S1=V2 RMS .I1 RMS (First apparent power).

[0116] The microcontroller 6 also estimates a third active power, a third reactive power, and a third apparent power consumed on the third phase by calculating as follows:

[0117]

[0118]

[0119] S3=V2 RMS .I3 RMS (Third apparent power).

[0120] The third phase shift So that:

[0121]

[0122] To estimate the third phase shift Microcontroller 6 calculates:

[0123]

[0124] The microcontroller 6 assimilates the following as:

[0125] (Phase of V3 - Phase of V2)

[0126] The third phase shift estimate, in this case equal to -120°, is a theoretical estimate of the expected phase shift between the third phase voltage V3 (whose measurement is not available in this case) and the (reference) second phase voltage V2 in the absence of fraud (ie, under normal conditions).

[0127] value:

[0128] (Phase of V2 - Phase of I2)

[0129] It is measured by the measuring component 6.

[0130] The value:

[0131] (Phase of I2 - Phase of I3)

[0132] It is measured by the measuring component 6.

[0133] refer to Figure 2 , this time a three-wire configuration is used.

[0134] The power distribution network 3 includes a first phase Ph1 , a second phase Ph2 , and a third phase Ph3 , but has no neutral line.

[0135] The meter 1 comprises four voltage input terminals Ue1 , Ue2 , Ue3 and three current input terminals Ie1 , 1e2 , Ie3 (each current input terminal comprises two ports).

[0136] The meter 1 again comprises a measuring component 5 and a microcontroller 6 connected to the measuring component 5 .

[0137] Again, use is made of the case in which the wire f1 has been cut by a malicious user.

[0138] Therefore, the following occurs:

[0139] V1 RMS <40V

[0140] And I1 RMS >5mA.

[0141] The microcontroller 6 has therefore detected a fraud that has tampered with at least one first voltage measurement, the image of the first phase voltage V1 present on the first phase Ph1 .

[0142] Assume that the microcontroller 6 has not detected fraud on the second phase Ph2 nor on the third phase Ph3. The second and third voltage measurements have therefore not been tampered with by the fraud affecting the first phase Ph1.

[0143] The implementation of the present invention is slightly different in a three-wire configuration. The reason for this difference is Figure 3 and 4 is illustrated in the diagram.

[0144] Figure 3 Indicated in Figure 1 Fresnel plots of voltage and current in the normal case (on the left-hand side) and in the fraudulent case involving cutting wire f1 (on the right-hand side) in the four-wire configuration in FIG.

[0145] Observe that the absence of a voltage measurement (in this case the V1 measurement) has no effect on the magnitude and angle of the other voltages. In the case of the absence of two voltages, the same applies to the remaining voltages.

[0146] Figure 4 Indicated in Figure 2 Fresnel diagrams of voltage and current in the normal case (on the left-hand side) and in the fraudulent case (on the right-hand side) involving cutting wire f1 in the three-wire configuration in FIG.

[0147] Observe that the lack of a voltage measurement (in this case the V1 measurement) has an effect on the measured amplitude But it will also have an effect on the measured angles of the other voltages (V2 measures +30°, while V3 measures -30°).

[0148] Therefore, the microcontroller 6 first preliminarily detects whether the power distribution network 3 includes a neutral line other than the three phases.

[0149] If this is not the case, i.e. if the configuration is a three-wire configuration, the microcontroller 6 takes into account the factor and phase shifts of +30° and -30° to estimate electrical power.

[0150] As you can see, the measured angle of V2 has increased by 30°.

[0151] Therefore, in the three-wire configuration, the first phase shift estimate equal to +120° is no longer equal to:

[0152] (Phase of V1 - Phase of V2),

[0153] But it is equivalent to:

[0154] (Phase of V1 - (Phase of V2 - 30°))

[0155] In fact, a phase difference of +120° corresponds to the phase difference between the first phase voltage V1 and the second phase voltage V2 when the measurement of the latter has not yet undergone an increase of +30° resulting from the absence of measurement of the first phase voltage V1 (in a three-wire configuration).

[0156] The phase value “phase −30° of V2 ” therefore corresponds to the phase value of the second virtual voltage measurement which has not yet been phase-shifted.

[0157] The microcontroller 6 therefore first calculates:

[0158]

[0159] value:

[0160]

[0161] It is measured by the measuring component 6.

[0162] value:

[0163] (Phase of I2 - Phase of I1)

[0164] It is measured by the measuring component 6.

[0165] The microcontroller 6 then estimates the first electrical power by the following formula:

[0166]

[0167]

[0168]

[0169] factor This enables the correction of the effects of fraud on amplitude already stated above.

[0170] Advantageously, when the microcontroller 6 has detected that the power distribution network 3 does not include a neutral line in addition to the three phases (three-wire configuration), and if the fraud has not tampered with the second voltage measurement, the microcontroller 6 also corrects at least one second electric power consumed on the second phase Ph2. Likewise, if the fraud has not tampered with the third voltage measurement, the microcontroller 6 also corrects at least one third electric power consumed on the third phase Ph3.

[0171] The correction includes: multiplying the at least one second electric power and the at least one third electric power by a same predetermined factor (amplitude correction), and phase shifting at least one second electric power with a predefined second phase shift and at least one third electric power with a predefined third phase shift (phase correction).

[0172] The predetermined factor is equal to The predefined second phase shift is equal to -30° and the predefined third phase shift is equal to +30°.

[0173] The microcontroller 6 therefore calculates:

[0174]

[0175]

[0176]

[0177]

[0178]

[0179]

[0180] value:

[0181]

[0182] It is measured by the measuring component 6.

[0183] As can be seen, the microcontroller must detect whether the configuration is a four-wire or three-wire configuration, i.e. whether the power distribution network 3 includes or does not include a neutral line in addition to the three phases. The estimation of the first electric power is actually different depending on the actual configuration. Likewise, the correction applied on the second and third electric powers depends on the configuration.

[0184] The power estimation method therefore comprises a preliminary step consisting in detecting whether the network 3 and the meter 1 are in a four-wire or three-wire configuration.

[0185] To this end, after having detected fraud on the first phase Ph1 , the microcontroller 6 measures the angle between the two remaining voltages, namely between the second phase voltage V2 and the third phase voltage V3 (Provided that the second voltage measurement V2 of the phase and the measurement of the third phase voltage V3 have not been tampered with).

[0186] Therefore, the microcontroller 6 determines the angle Is it at an absolute value close to 180°, if this is the case, a three-wire configuration is detected.

[0187] Microcontroller 6 verification angle Is it a predefined interval?

[0188]

[0189] X is a positive predefined value and is less than 30. For example, the following situation occurs: X=20.

[0190] If the angle belongs to the predefined interval, the microcontroller 6 considers the angle In an absolute value close to 180°, and therefore a three-wire configuration is detected. Otherwise, the microcontroller 6 detects a four-wire configuration.

[0191] Note that in a three-wire configuration it is possible to estimate the power consumed without fraud only if only one voltage input is lost (fraud on a single phase, as in three-wire, if two phases are lost the meter is no longer powered), while in a four-wire configuration it is possible to estimate them in the case of loss of two voltage inputs.

[0192] It should also be noted that in the case where the microcontroller 6 detects the loss of two voltage inputs (fraud on two phases), the microcontroller 6 can systematically detect a four-wire configuration (because the meter 1 is powered); therefore, the meter 1 performs the estimation method under the corresponding conditions. In fact, when the configuration is a three-wire configuration and two voltages are lost, the meter automatically shuts down.

[0193] In a variant, and whatever the configuration (four-wire or three-wire), in the case where the fraud affects only the first phase Ph1, it is possible to estimate the first electric power, acquiring at least one second voltage measurement, an image of the second phase voltage V2 present on the second phase Ph2, and at least one third phase voltage, an image of the third phase voltage V3 present on the third phase Ph3.

[0194] The microcontroller thus calculates the arithmetic mean of the at least one second voltage measurement and the at least one third voltage measurement to estimate the at least one first electrical power.

[0195] In this case, the microcontroller 6 therefore calculates V2 RMS and V3 RMS The arithmetic mean of the first active power and the first apparent power is used to estimate the first active power and the first apparent power, and to calculate VF2 RMS and VF3 RMS The arithmetic mean of is used to estimate the first reactive power.

[0196] It is also possible to use the first phase shift obtained by calculation using measurements on the second phase Ph2 and the first phase shift obtained by using the measurement on the third phase Ph3 The first “average” phase shift is obtained by taking the arithmetic mean of

[0197] The different steps of the estimation method can be found in Figure 5 As seen in.

[0198] The method starts at step E0.

[0199] The microcontroller 6 attempts to detect at least one fraud on one of the three phases (step E1 ).

[0200] If no fraud is detected, the microcontroller 6 acquires estimates of the active, reactive and apparent powers calculated by the measuring assembly 6 for the three phases and does not correct these estimates (step E2 ). The acquisition of power is carried out at fixed intervals (for example a period of 1 s).

[0201] The method returns to step E1.

[0202] If, in step E1 , the microcontroller 6 detects fraud on both phases, the microcontroller 6 infers directly from this that the configuration is a four-wire configuration (see what has just been explained).

[0203] For example, assume that a first voltage measurement (of the first phase voltage V1 ) and a third voltage measurement (of the third phase voltage V3 ) are tampered with.

[0204] The microcontroller 6 thus acquires the measurements produced by the measuring arrangement 5 .

[0205] For the first phase Ph1 , the microcontroller estimates a first active power, a first reactive power and a first apparent power from measurements on the second phase Ph2 (which have not been tampered with): step E3 . The second phase Ph2 is the reference phase.

[0206] Therefore, for the third phase Ph3 , the microcontroller 6 estimates a third active power, a third reactive power and a third apparent power from the measurements on the second phase Ph2 (step E4 ).

[0207] For the second phase Ph2 , the microcontroller 6 acquires estimates of the second active power, the second reactive power and the second apparent power, which are calculated by the measurement assembly 5 , and does not correct these estimates (because the configuration is a 4-wire configuration).

[0208] The power is collected at fixed intervals (eg, a period of 1 s). The method returns to step E1.

[0209] Assume now that in step E1 the microcontroller 6 detects fraud on a single phase; assume that the first phase voltage measurement (first phase voltage V1 ) is tampered with.

[0210] The microcontroller 6 thus detects whether the network 3 and the meter 1 are in a four-wire or three-wire configuration (step E5 ).

[0211] If a three-wire configuration is detected, the microcontroller 6 acquires the measurements produced by the measuring assembly 5 and therefore estimates, for the first phase Ph1, the first active power, the first reactive power and the first apparent power from the measurements on the second phase Ph2 (which have not been tampered with): step E6. The second phase Ph2 is the second reference phase. The microcontroller 6 will also already be able to use the measurements on the third phase Ph3.

[0212] Furthermore, the microcontroller 6 acquires the power estimates generated by the measuring assembly 5 for the second phase Ph2 and the third phase Ph3 and corrects these power estimates accordingly (amplitude correction and phase correction): step E7 .

[0213] The power is collected at fixed intervals (eg, a period of 1 s).

[0214] The method therefore returns to step E1 .

[0215] In step E5, if a four-wire configuration is detected, the microcontroller 6 acquires the measurements produced by the measuring assembly 5 and therefore estimates, for the first phase Ph1, a first active power, a first reactive power and a first apparent power from the measurements on the second phase Ph2 (which have not been tampered with): step E8. The second phase Ph2 is the reference phase. The microcontroller 6 will also have been able to use the measurements on the third phase Ph3.

[0216] The microcontroller 6 acquires the power estimates generated by the measuring assembly for the second and third phases without performing any corrections.

[0217] The power is collected at fixed intervals (eg, a period of 1 s).

[0218] The method therefore returns to step E1 .

[0219] Naturally, the invention is not limited to the embodiments described but covers any variant coming within the ambit of the invention as defined by the claims.

[0220] This shows that the first phase shift estimate enabling estimation of the phase shift between the first phase voltage and the second phase voltage is equal to +120°. Naturally, this value depends on the phases referred to as "first phase" and "second phase"; the first phase shift estimate may be equal to -120°.

[0221] Likewise, the predefined second phase shift may be equal to +30° and the predefined third phase shift equal to -30°.

Claims

1. A power estimation method implemented in a three-phase electricity meter (1) connected to three phases of a power distribution network (3), and comprising the following steps: detecting fraud, said fraud tampering with at least one first voltage measurement, an image of a first phase voltage (V1) present on a first phase (Ph1); acquiring an image of at least one second voltage measurement, a second phase voltage (V2) present on a second phase (Ph2), the at least one second voltage measurement not tampered with by the fraud; Characterized in that the power estimation method further comprises the following steps: estimating a first phase shift between the first phase voltage (V1) and a first phase current (I1) circulating on the first phase by using a first phase shift estimate, the first phase shift estimate being a theoretical estimate of an expected phase shift between the first phase voltage (V1) and the second phase voltage (V2) in the absence of fraud; At least one first electrical power consumed on the first phase is estimated from at least one first current measurement, the image of the first phase current, the at least one second voltage measurement, and the first phase shift.

2. The power estimation method according to claim 1, characterized in that: The first phase shift is estimated from a phase shift between the second phase voltage (V2) and a second phase current (I2) circulating on the second phase, a phase difference between the second phase current (I2) and the first phase current (I1), and the first phase shift estimate.

3. The power estimation method according to any one of the preceding claims, characterized in that The first phase shift is equal to +120° or -120°.

4. The power estimation method according to claim 1 or 2, characterized in that: The at least one second voltage measurement comprises an effective value of the second phase voltage (V2) and / or a level of a fundamental frequency of the second phase voltage (V2).

5. The power estimation method according to claim 4, characterized in that: The at least one first electric power comprises a first active power estimated from the effective value of the second phase voltage, the effective value of the first phase current, and the first phase shift; and / or a first reactive power estimated from a level at the fundamental frequency of the second phase voltage, a level at the fundamental frequency of the first phase current, and the first phase shift; and / or a first apparent power estimated from an effective value of the second phase voltage and an effective value of the first phase current.

6. The power estimation method according to claim 1 or 2, characterized in that: The fraud is detected when the at least one first voltage measurement is less than a predefined voltage threshold and the at least one first current measurement is greater than a predefined current threshold.

7. The power estimation method according to claim 1 or 2, characterized in that: The following steps are also included: If the fraud also tampered with at least one third voltage measurement, an image of a third phase voltage (V3) present on a third phase (Ph3), the at least one second voltage measurement is again used to estimate at least one third electrical power consumed on the third phase.

8. The power estimation method according to claim 1 or 2, characterized in that: The following steps are also included: capturing an image of at least one third voltage measurement, a third phase voltage (V3) present on a third phase (Ph3), said third voltage measurement not being tampered with by said fraud; An arithmetic mean of the at least one second voltage measurement and the at least one third voltage measurement is calculated to estimate the at least one first electrical power.

9. The power estimation method according to claim 8, characterized in that: The first phase shift is obtained by calculating an arithmetic mean of a phase shift obtained by using a measurement on the second phase (Ph2) and a phase shift obtained by using a measurement on the third phase (Ph3).

10. The power estimation method according to claim 1 or 2, characterized in that: The following steps are also included: It is detected whether the power distribution network (3) includes or does not include a neutral conductor (N) in addition to the three phases and, if this is not the case, correct at least one second electric power consumed on the second phase (Ph2) and, if the fraud has not tampered with at least one third voltage measurement, an image of a third phase voltage present on the third phase, also correct at least one third electric power consumed on the third phase (Ph3).

11. The power estimation method according to claim 10, characterized in that: The correction comprises multiplying the at least one second electric power and the at least one third electric power by a same predetermined factor and phase shifting the at least one second electric power by a predefined second phase shift and the at least one third electric power by a predefined third phase shift.

12. The power estimation method according to claim 11, characterized in that: The predetermined factor is equal to And wherein the predefined second phase shift is equal to -30°, and the predefined third phase shift is equal to +30°.

13. The power estimation method according to claim 11, characterized in that: When the angle between the second phase voltage (V2) and the third phase voltage (V3) The absence of neutral (N) is detected when: X is a positive predefined value and is less than 30.

14. A three-phase electricity meter comprising a processing component (6) arranged to implement the power estimation method as claimed in one of the preceding claims.

15. The three-phase electric meter according to claim 14, characterized in that: Also included is a measurement component (5) separate from the processing component (6) and arranged to generate the at least one first voltage measurement, the at least one second voltage measurement and the at least one first current measurement.

16. A recording medium readable by a computer, on which a computer program including instructions is recorded, wherein the instructions drive the three-phase electricity meter (1) according to one of claims 14 or 15 to execute the steps of the power estimation method according to one of claims 1 to 13.

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