Method for determining power consumption of electrical installation

Abstract

The subject of the invention is a method for determining the power consumption of an electrical installation. In order to determine the power consumption of an electrical installation powered by at least one phase and monitored by an electricity meter, a method implemented by a controller of an electricity meter comprises: obtaining (601, 603), for each phase, a sample of a voltage measurement and a sample of a current measurement; applying (602) the amplitude adjustment KU and the phase adjustment [Delta] [phi] to the voltage measurement sample to obtain an adjusted voltage sample; applying (604) the amplitude adjustment KI and the phase adjustment [Delta] [phi] 'to the current measurement sample to obtain an adjusted current sample, performing (605) at least one power calculation from the adjusted voltage sample and the adjusted current sample, and determining (606) the power consumption from the at least one power calculation.

Description

Technical Field

[0001] The invention relates to the adjustment of measurements made by an electricity meter in order to take into account the lack of precision of the characteristics of components of the meter used to make voltage and current measurements used to determine the electricity consumption of an electrical installation monitored by the meter. Background Art

[0002] To determine the power consumption of an electrical installation, the meter uses samples of the alternating voltage and current measurements at the input of the electrical installation for power calculations. The measurements of the alternating voltage and current are made with the aid of electronic components: the voltage is usually measured with the aid of a voltage divider bridge; in single-phase, the current is usually measured with the aid of a measuring shunt; in multiphase (e.g. three-phase), the current is usually measured with the aid of a torus.

[0003] Figure 1 The arrangement of samples for obtaining AC voltage and current measurements between the phase conductor P and the neutral conductor N in a single-phase electricity meter is schematically illustrated.

[0004] The voltage divider bridge is realized with the help of resistors R1 and R2 between the neutral line N and ground. An analog-to-digital converter C2 placed at the connection point of the resistors R1 and R2 makes it possible to obtain voltage measurement samples.

[0005] A shunt realized by a calibration resistor R3 is placed on the phase line P. The phase line P is here connected to ground. A current measurement chain CMC coupled to an analog-to-digital converter C1 makes it possible to obtain current measurement samples.

[0006] The electric meter comprises a controller CTRL configured to determine the power consumption based on a power calculation performed using samples of the obtained AC voltage and current measurements, as described below with reference to Figure 3 As described in detail.

[0007] Figure 2 Schematically illustrated is an arrangement of samples for obtaining AC voltage and current measurements between the phase line P and the neutral line N in a multi-phase (eg three-phase) electricity meter. The neutral line N is here connected to ground.

[0008] The voltage divider bridge is realized by means of resistors R1 and R2 between the phase line P in question and ground. An analog-to-digital converter C2 placed at the connection point of the resistors R1 and R2 makes it possible to obtain voltage measurement samples.

[0009] The toroid T is placed on phase P, in parallel with the resistor R4. A current measurement chain CMC coupled to an analog-to-digital converter C1 makes it possible to obtain current measurement samples.

[0010] Figure 2The arrangement in is repeated for each phase, however the controller CTRL is here common to the various phases. The controller CTRL is thus configured to determine the power consumption from a power calculation using samples of the alternating voltage and current measurements obtained for each of the phases.

[0011] The actual characteristics of the shunt, toroid, and resistor are specific to each meter. For example, the accuracy of the shunt is given as ±5%, and the accuracy of the resistor is given as ±1%, and the toroid can shift the phase of the current signal by a few degrees. The result of the power calculation is then usually adjusted to compensate for the difference in the effective accuracy of the characteristics of the electronic components used to make the AC voltage and current measurements.

[0012] Therefore, if Figure 3 As explained above, the controller CTRL performs, for example, an active power calculation P and a reactive power calculation Q based on samples of the voltage measurement U and the current measurement I obtained. The power P and Q are adjusted by means of a matrix calculation MAT to compensate for the phase shift and gain caused by the annulus for each phase in a multiphase (e.g. three-phase) or by the shunt in a single phase, so as to obtain a corrected active power Pm and a corrected reactive power Qm. The matrix calculation MAT includes predefined phase compensations, respectively and a predefined amplitude compensation K.

[0013] Given that power calculations are complex calculations that combine the sum of multiples of the voltage and current samples, phase compensation in these power calculations The amplitude compensation K results in a residual lack of precision. This residual lack of precision is all the greater in multiphases (eg three phases) because the phase shift, in particular in relation to the torus, is different from one phase to another.

[0014] It would therefore be desirable to overcome these shortcomings of the prior art. Summary of the invention

[0015] A method for determining the power consumption of an electrical installation is proposed, the electrical installation being powered by at least one phase and being monitored by an electric meter, the method being implemented by a controller of the electric meter and comprising: obtaining a sample of voltage measurement and a sample of current measurement for each phase; adjusting the amplitude K U and phase adjustment Applied to the voltage measurement samples to obtain adjusted voltage samples; adjust the amplitude by K I and phase adjustment Applying to the current measurement sample to obtain an adjusted current sample; performing at least one power calculation based on the adjusted current sample; and determining the power consumption based on the at least one power calculation. In addition, in order to obtain the adjusted current sample, the method further includes: applying the supplementary adjustment K′I Applied to the current measurement samples to compensate for the expansion of the voltage measurement samples relative to the current measurement samples.

[0016] Thus, by applying the amplitude and phase adjustment to the measurement samples instead of to the at least one power calculation, a better metering accuracy is obtained.In addition, the spreading of the voltage measurement samples relative to the current measurement samples is compensated, which improves the accuracy.

[0017] According to certain embodiments, the phase adjustment is applied by interpolation According to the sampling period T E The corresponding time t n-1 =(n-1)×T E and t n =n×T E Two consecutive voltage measurement samples U n-1 and U n Between, interpolation at the virtual sampling time t n-1+r =(n-1+r)×T E Provide sample U n-1+r , where r makes And apply phase adjustment by interpolation At the corresponding time t n-1 =(n-1)×T E and t n =n×T E Two consecutive current measurement samples I n-1 and I n Between, interpolation at the virtual sampling time t n-1+r’ =(n-1+r')×T E Provide sample I n-1+r’ , where r′ makes

[0018] According to a particular embodiment, the interpolation is linear, wherein the linear interpolation provides the interpolated voltage samples U n-1+r and the interpolated current sample I n-1+r’ , so that:

[0019] U n-1+r =(1+K U )×(r×U n +(1-r)×U n-1 )and

[0020] I n-1+r′ =(1+K I )×(r′×I n +(I-r')×I n-1 )+K' I ×U n-1+r

[0021] According to a particular embodiment, the electrical installation monitored by the meter is powered in three phases. Therefore, the adjustment of the amplitude and phase of the measurement samples will be even more precise than it would be by adjusting the amplitude and phase of the at least one power calculation (because of the distinct phase shift introduced in particular by the toroid used on the phases for making the current measurement).

[0022] According to a specific embodiment, said at least one power calculation is an active power and / or reactive power and / or apparent power calculation.

[0023] Also proposed herein is a computer program comprising program code instructions which, when the instructions are executed by a smart meter processor, cause the implementation of the method.

[0024] An information storage medium storing such program code instructions is also proposed herein.

[0025] Here, an electric meter controller is also proposed, the electric meter controller is configured to determine the power consumption of an electrical facility, the electric facility is powered by at least one phase and is monitored by an electric meter, the controller includes an electronic circuit, the electronic circuit is configured to: obtain a sample of voltage measurement and a sample of current measurement for each phase; adjust the amplitude K U and phase adjustment Applied to the voltage measurement samples to obtain adjusted voltage samples; adjust the amplitude by K I and phase adjustment Applying to the current measurement sample to obtain an adjusted current sample; performing at least one power calculation based on the adjusted voltage and current samples; and determining the power consumption based on the at least one power calculation. In addition, in order to obtain the adjusted current sample, the method further includes: adding a supplementary adjustment K' I Applied to the current measurement samples to compensate for the expansion of the voltage measurement samples relative to the current measurement samples.

[0026] An electric meter equipped with the above controller is also proposed herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The characteristics of the invention mentioned above, as well as other characteristics, will emerge more clearly from a reading of the following description of at least one example embodiment, said description being made in relation to the accompanying drawings, in which:

[0028] Figure 1 Schematically illustrates the arrangement of samples for obtaining voltage and current measurements in a single-phase electricity meter;

[0029] Figure 2 schematically illustrates the arrangement of samples for obtaining voltage and current measurements for each phase in a polyphase electricity meter;

[0030] Figure 3 schematically illustrates an arrangement for performing power calculations to determine power consumption according to the prior art;

[0031] Figure 4 Schematically illustrates an arrangement for performing power calculations to determine power consumption according to one embodiment of the present invention;

[0032] Figure 5 An example of a hardware arrangement of an electricity meter controller is schematically illustrated;

[0033] Figure 6 An algorithm for performing power calculation to determine power consumption according to an embodiment of the present invention is schematically illustrated; and

[0034] Figure 7 An example of linear interpolation for adjusting samples for phase according to an embodiment of the present invention is schematically illustrated. DETAILED DESCRIPTION

[0035] Figure 4 An arrangement for performing a power calculation to determine an amount of power consumption according to an embodiment of the invention is schematically illustrated.The power calculation is performed to determine an amount of power consumption of an electrical installation, the electrical installation being powered by at least one phase and monitored by an electricity meter. Figure 4 Based on the samples used to obtain voltage and current measurements Figure 1 Arrangement in or Figure 2 The arrangement in .

[0036] Figure 4 includes active power calculation P and reactive power calculation Q. However, instead of Figure 3 Based on these power calculations on samples of the original voltage U and current I measurements, as in the context of , the active power P and reactive power Q calculations use voltage and current samples adjusted in terms of amplitude and phase. Thus, the samples of the voltage measurement U provided by the analog-to-digital converter C2 undergo a phase shift adjustment for amplitude (gain K U ) and for phase The adjustment A2 and the sample of the current measurement I provided by the analog-to-digital converter C1 undergoes a step-by-step adjustment for the amplitude (gain K I ) and for phase Adjustment A1 of (usually different adjustment compared to the sample for voltage measurement U).

[0037] The accuracy of power consumption measurement is improved by obtaining the corrected active power Pm and the corrected reactive power Qm by calculating the active power P and the reactive power Q based on the voltage and current samples adjusted in terms of amplitude and phase (rather than performing amplitude and phase compensation after the active power P and the reactive power Q are calculated).

[0038] Figure 5 An example of a hardware arrangement of a controller CTRL suitable for power and current consumption calculation according to the invention is schematically illustrated.

[0039] The controller CTRL 500 comprises, connected via a communication bus 510: a processor or CPU (“Central Processing Unit”) 501; a random access memory (RAM) 502; a read-only memory 503, for example of the ROM (“Read Only Memory”) or EEPROM (“Electrically Erasable Programmable Read Only Memory”) type, such as a flash memory; a storage unit SM 504, such as a hard disk drive HDD or a SD (Secure Digital) card reader; and an interface manager I / f505.

[0040] The interface manager I / f 505 enables the controller CTRL 500 to interact with other devices of the meter, such as a transceiver, for example, when the meter is a communication meter. The interface manager I / f 505 enables the controller CTRL 500 to receive samples of the voltage measurements U and I from the analog-to-digital converter. In a variant embodiment, the analog-to-digital converter is included in the controller CTRL 500, for example in the interface manager I / f 505.

[0041] The processor 501 can execute instructions loaded from the read-only memory 503, from an external memory, from a storage medium (such as an SD card), or from a communication network into the random access memory 502. When the controller CTRL 500 is powered on, the processor 501 can read instructions from the random access memory 502 and execute them. These instructions form a computer program that causes all or some of the steps, methods, and operations described herein to be implemented by the processor 501.

[0042] All or some of the steps, methods and operations described herein may thus be implemented in software by executing a set of instructions by a programmable machine, such as a processor or microcontroller of the DSP (“digital signal processor”) type, or in hardware by a machine or a dedicated electronic component (chip) or a collection of dedicated electronic components (chip set), such as an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit). In general, the controller CTRL 500 (and therefore the electric meter) comprises electronic circuits adapted and configured to implement the operations, methods and steps described herein.

[0043] Figure 6 An algorithm for performing power calculation to determine power consumption according to one embodiment of the present invention is schematically illustrated.

[0044] In step 601 , the controller CTRL obtains voltage measurement samples.

[0045] In step 602, the controller CTRL performs a phase shift operation on the obtained voltage measurement samples. and amplitude K U Adjustment is performed to obtain adjusted voltage samples.

[0046] Steps 601 and 602 are performed for each phase (ie, for each of three of the three phases).

[0047] In step 603 , the controller CTRL obtains current measurement samples.

[0048] In step 604, the controller CTRL performs a phase shift operation on the obtained current measurement samples. and amplitude K I The adjustment is performed in order to obtain the adjusted current sample.

[0049] Steps 603 and 604 are performed for each phase (ie, for each of three of the three phases).

[0050] In a specific embodiment, the controller CTRL obtains the voltage measurement sample U n-1 And the voltage measurement sample U n Interpolation between, define r so that and then adjust K by applying the magnitude U To obtain the voltage sample U adjusted for the phase n-1+r In a similar manner, the controller CTRL obtains the current measurement samples I n-1 and obtain the current measurement sample I n interpolate between and then adjust K by applying the magnitudeI (Define r′ so that ) to obtain the current sample I adjusted for the phase n-1+r’ .

[0051] Interpolation can be quadratic, cubic, or spline.

[0052] In a specific embodiment, as in Figure 7 As schematically illustrated above, the interpolation is linear. Figure 7 Included are points on the sinusoidal curve which represent samples of measurements (of voltage or current) as provided by the analog-to-digital converter.On the X-axis is shown time and on the Y-axis is shown the measurement sample value.

[0053] The samples correspond to the sampling period T E The measurement (provided by the analog-to-digital converter) is performed within 384.62 μs, thus corresponding to a sampling frequency f of 2600 Hz. E . Point A n-1和 A n Corresponding to the corresponding measurement time t n-1 =(n-1)×T E and t n =n×T E The continuous measurement samples and have corresponding measurement values ​​V n-1 and V n . Point A n-1+r is the virtual measurement time t n-1+r =(n-1+r)×T E The interpolated point, where the interpolated amplitude value is V n-1+r So: V n-1+r =r×V n +(1-r)×V n-1 Linear interpolation is computationally advantageously simple and requires few resources.

[0054] Therefore, for each phase:

[0055] U n-1+r =(1+K U )×(r×U n +(1-r)×U n-1 )

[0056] I n-1+r '=(1+K I )×(r′×I n +(1-r')×I n-1 )

[0057] K U , K I, r and r′ are constants specific to each meter and to each phase. K is calibrated in the factory using measurements U , K I , r and r', the expected result of the measurement is known and it is necessary to trend towards the measurement. This consists of solving a system of multiple equations with several unknowns.

[0058] In addition, the controller CTRL makes an additional adjustment to the current measurement samples to compensate for the expansion of the voltage measurement samples relative to the current measurement samples. Such expansion has been found on some analog-to-digital converters that provide voltage and current samples in the form of multiplexed channels. The controller CTRL then adjusts the gain K' I Applied to the corresponding (adjusted) voltage sample U for the phase involved n-1+r Then, in the case of linear interpolation described above, for each phase the current samples are adjusted in the following way:

[0059] I n-1+r’ =(I+K I )×(r′×I n +(1-r')×I n-1 )+K' I ×U n-1+r

[0060] In this case, K is calibrated in the factory using measurements U , K I , K' I , r and r', the expected result of the measurement is known and it is necessary to tend towards the measurement. This consists of solving another system of multiple equations with several unknowns.

[0061] In step 605, the controller CTRL uses the adjusted voltage and current samples (U n-1+r and I n-1+r’ ) to perform at least one power calculation.

[0062] The power calculation may be an active power and / or a reactive power and / or an apparent power calculation.

[0063] In step 606 , the controller CTRL determines the power consumption of the electrical appliance based on the at least one power calculation of step 605 .

[0064] It should be noted that, considering a three-phase electricity meter comprising three torus T1, T2 and T3, the phase difference between torus T1 and (e.g. +1.5°), the phase difference of the torus T2 (e.g. -0.7°) and the phase difference of the torus T3 (e.g. -1°), it is not possible to choose a sampling instant that makes it possible to compensate these three phase differences simultaneously (because these phase differences have different values). It is therefore obvious that it is preferable to interpolate the samples U and I as proposed in the solution, rather than to correct the phase differences by acting on the sampling instants.

Claims

1. A method for determining the power consumption of an electrical installation, the electrical installation being powered by at least one phase and being monitored by an electric meter, the method being implemented by a controller (500) of the electric meter, and comprising: obtaining (601, 603) samples of voltage measurements and samples of current measurements for each phase; Adjust the amplitude K U and phase adjustment applying (602) to the voltage measurement samples to obtain adjusted voltage samples; Adjust the amplitude K I and phase adjustment applying (604) to the current measurement samples to obtain adjusted current samples; performing (605) at least one power calculation based on the adjusted voltage samples and the adjusted current samples; and determining (606) the power consumption based on the at least one power calculation, Characterized in that the method further comprises, in order to obtain the adjusted current sample: A supplementary adjustment is applied to the current measurement samples to compensate for the expansion of the voltage measurement samples relative to the current measurement samples, the supplementary adjustment being a gain K' I The voltage samples are applied to the corresponding adjustments.

2. The method according to claim 1, wherein: The phase adjustment Δφ is applied by interpolation, where, according to the sampling period T E The corresponding time t n-1 =(n-1)×T E and t n =n×T E Two consecutive voltage measurement samples U n-1 and U n The interpolation is performed at the virtual sampling time t n-1+r =(n-1+r)×T E Provide sample U n-1+r , where r is such that and The phase adjustment is applied by interpolation Among them, at the corresponding time t n-1 =(n-1)×T E and t n =n×T E Two consecutive current measurement samples I n-1 and I n The interpolation is performed at the virtual sampling time t n-1+r’ =(n-1+r')×T E Provide sample I n-1+r’ , where r' makes 3. The method according to claim 2, wherein: The interpolation is linear, wherein the linear interpolation provides interpolated voltage samples U n-1+r and the interpolated current sample I n-1+r , so that: U n-1+r =(1+K U )×(r×U n +(1-r)×U n-1 )and I n-1+r’ =(I+K I )×(r’×I n +(1-r’)×I n-1 )+K’ I ×U n-1+r 。 4. The method according to claim 1, wherein: The electrical utility monitored by the electric meter is powered in three phases.

5. The method according to claim 1, wherein: The at least one power calculation is an active power and / or reactive power and / or apparent power calculation.

6. An information storage medium storing program code instructions which, when read and executed by a processor of an electricity meter controller (500), cause implementation of the method according to any one of claims 1 to 5.

7. An electric meter controller (500) configured to determine the amount of electricity consumed by an electrical appliance, the electrical appliance being powered by at least one phase and being monitored by the electric meter, the controller (500) comprising an electronic circuit configured to: obtaining (601, 603) samples of voltage measurements and samples of current measurements for each phase; Adjust the amplitude K U and phase adjustment applying (602) to the voltage measurement samples to obtain adjusted voltage samples; Adjust the amplitude K I and phase adjustment applying (604) to the current measurement samples to obtain adjusted current samples; performing (605) at least one power calculation based on the adjusted voltage samples and the adjusted current samples; and determining (606) the power consumption based on the at least one power calculation, It is characterized in that The electronic circuit is further configured to obtain the adjusted current sample by: A supplementary adjustment is applied to the current measurement samples to compensate for the expansion of the voltage measurement samples relative to the current measurement samples, the supplementary adjustment being a gain K' I The voltage samples are applied to the corresponding adjustments.

8. An electric meter comprising the controller (500) according to claim 7.

Images