ELECTRICAL DEVICE AND METHOD FOR DETECTING FRAUD BY CIRCUMVENTION
The method measures neutral conductor current to detect fraud in electrical installations, addressing the challenge of high voltages in energy production mode, ensuring reliable fraud detection without power interruptions or energy loss.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Applications
- Current Assignee / Owner
- SAGEMCOM ENERGY & TELECOM SAS
- Filing Date
- 2024-12-10
- Publication Date
- 2026-06-12
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
Title of the invention: ELECTRICAL DEVICE AND METHOD FOR DETECTING FRAUD BY CIRCUMVENTION technical field
[0001] The various embodiments described in this disclosure relate to an electrical device, particularly an electricity meter for an electrical installation that can operate in energy consumption mode or in energy production mode (for example, an installation equipped with solar panels or wind turbines). They also relate to a method for detecting fraud by bypassing such an installation.
[0002] BACKGROUND
[0003] The electrical installation is connected via the electricity meter to an electrical network comprising one or more phase conductors and a neutral conductor. The meter typically includes, for each phase conductor, a power relay that can be closed or opened to manage the connection between the electrical network and the electrical installation.
[0004] Fraud by bypassing the meter consists of short-circuiting one or more phase connectors and possibly the neutral conductor. Fraud can be detected by monitoring the current flowing in the neutral conductor. A non-zero sum of the currents flowing in the phase conductor(s) and the neutral conductor indicates fraud.
[0005] Tamper detection is more complex when it involves all conductors, both phase and neutral. In this case, it is known to open the power relay(s) and measure the voltage across the relay(s). The downstream voltage (on the electrical installation side) should be very low compared to the upstream voltage (on the network side). A small potential difference between the upstream and downstream points indicates a bypass on the phase connector in question.
[0006] However, this method is not applicable to modern installations capable of operating in power generation mode. Indeed, in this case, the presence of a high voltage on the installation side when the power relay is open is not necessarily an anomaly.
[0007] The present disclosure provides a solution for installations that can operate in energy production mode.
[0008] SUMMARY
[0009] The independent claims define several aspects of this disclosure. In addition, other aspects or embodiments are defined in the dependent claims.
[0010] A first aspect of this disclosure relates to a method for detecting fraud by circumvention in an electrical installation connected to an electrical network via an electricity meter. The electrical network comprises one or more phase conductors and a neutral conductor. The electrical installation is configured to operate in energy consumption mode or energy production mode, and the meter has a power relay on each phase conductor. The method described herein comprises the following steps: determining whether the installation is operating in energy production mode; opening the power relay(s); measuring the current flowing in the neutral conductor; and generating an alert based on that measurement.
[0011] When the relay(s) are open, the current flowing in the neutral conductor is normally very low. A non-zero current in the neutral conductor indicates a bypass of at least one phase conductor and possibly a bypass of the neutral conductor (the current is then shared between the bypass and the neutral conductor).
[0012] This fraud detection method is suitable for installations that can operate in energy consumption mode (energy is then imported from the grid to the installation) or in energy production mode (energy is then exported from the installation to the grid). It detects fraud when at least one phase conductor is bypassed. Fraud detection occurs in energy production mode. This solution is advantageous because it avoids opening the power relay(s) when the installation is in energy consumption mode. The user is therefore not inconvenienced by the opening of the relay(s): there is no power interruption. When the installation is in energy production mode and the relay(s) are open, the energy produced is reused within the installation. The opening of the relay(s) therefore does not result in any energy loss.
[0013] This process also has the advantage of being simple, not requiring additional components compared to existing meters and therefore not involving additional costs.
[0014] In one embodiment, these operations are repeated periodically as long as no alert has been generated. For example, they can be repeated every hour. The objective here is to avoid opening the power relays too frequently.
[0015] In one embodiment, the method comprises a calculation of the overall active power associated with the phase conductor(s), and the determination of the operating Production mode occurs when the overall active power is negative for a predefined period.
[0016] In one embodiment, the opening of the power relay(s) occurs after verification that the current flowing in the neutral conductor exceeds a first threshold. This embodiment is advantageous in the case of a polyphase network, to avoid any false alarm due to a normal imbalance between the network phases resulting in a non-zero, but normal, current on the neutral conductor.
[0017] In one embodiment, the alert is generated when the measurement of the current flowing in the neutral conductor, with the power relay(s) open, is greater than a second threshold.
[0018] Another aspect of this disclosure relates to an electrical device intended to be mounted between an electrical network and an electrical installation, the electrical network comprising one or more phase conductors and a neutral conductor, and the electrical installation being configured to operate in energy consumption mode or energy production mode. The device comprises a power relay on each phase conductor, mounted between the electrical network and the electrical installation, and at least one microprocessor assembly configured to perform the operations described above.
[0019] Another aspect relates to a computer program product comprising instructions which, when executed by at least one processor, cause the implementation of the fraud detection process described above.
[0020] Another aspect relates to a non-transient storage medium readable by a computer comprising instructions which, when executed by a processor, cause the implementation of the fraud detection process described above. BRIEF DESCRIPTION OF THE FIGURES
[0021] The implementation examples will be better understood in the light of the detailed description that follows and the accompanying drawings, which are given for illustrative purposes only and are therefore not limiting to this disclosure.
[0022] Figure [Fig.1] is a block diagram of a first example of an electrical device according to the present disclosure, in the case of a single-phase network, in the absence of fraud.
[0023] Figure [Fig.2] is a block diagram of the same example of electrical device as that of Figure [Fig.1], in the case of fraud by bypassing the phase conductor and the neutral conductor.
[0024] Figure [Fig.3] is a block diagram of a second example of an electrical device according to the present disclosure, in the case of a three-phase network, with fraud by bypassing the phase conductors and the neutral conductor.
[0025] Figure [Fig.4] is a flowchart of a fraud detection process intended to be implemented in a device of the type described in Figures [Fig.1] to [Fig.3]. DETAILED DESCRIPTION
[0026] Various embodiment examples will now be described in more detail, without limitation, with reference to the drawings accompanying this disclosure, which illustrate certain embodiment examples.
[0027] Figure [Fig. 1] describes an electrical device 10 mounted between a single-phase electrical network 11 and an electrical installation 12. The network 11 includes a phase conductor P, which in this embodiment is connected to ground, and a neutral conductor N, which in this example is connected to the high voltage point (typically 230V). The device 10 also includes a power supply 14 connected to the two connectors P and N, and a microprocessor 16. The microprocessor 16 has at least one metrology function, i.e., measuring currents and voltages at various points and calculating the energy imported and the energy exported by the installation 12 (typically the microprocessor 16 includes sensors and an analog-to-digital converter to obtain samples at a sampling frequency from which it performs the calculations).A measuring resistor RI1 (shunt resistor) is mounted on the phase connector P upstream of a power relay XI connected to the installation 12. The measuring resistor RI1 allows the measurement of a current IP flowing through the phase conductor P. The power relay XI allows the installation 12 to be disconnected from the network 11. A TN transformer, with a ratio K (typically 2000), is mounted on the neutral conductor N. A resistor R1N (typically 10 Ohms) connects the secondary of the TN transformer to ground. Measuring the voltage across resistor R1N allows the current IN / K to be determined, and thus the current IN flowing through the conductor N to be deduced. The use of a transformer on the neutral conductor is necessary to ensure insulation between the phase conductor and the neutral conductor. The microprocessor 16 controls the power relay XI as indicated by arrow C. In Figure [Fig.[l] Installation 12 operates in consumption mode: the current in the phase conductor flows from network 11 to installation 12 (arrow 17). The current in the neutral connector flows from installation 12 to network 11 (arrow 18).
[0028] Figure [Fig.2] reproduces the same example of an electrical device as that of Figure [Fig.1], in the case of fraud by bypassing the phase conductor P and the neutral conductor N. The bypasses of the phase conductor P and the neutral conductor N are respectively labeled BP and BN. In Figure [Fig. 2], we consider the case where the installation is operating in power generation mode and the power relay XI is open: the current flows via the bypass BP from installation 12 to network 11 (arrow 27), and through the bypass BN from network 11 to installation 12 (arrow 28). Part of the current also flows on the neutral conductor N from network 11 to installation 12.
[0029] Figure [Fig. 3] shows a second example of an electrical device according to this disclosure, in the case of a three-phase network, with fraud by bypassing the phase conductors and the neutral conductor. In this example, the network comprises three phase conductors P1, P2, and P3 and one neutral conductor N. The phase conductors P1, P2, and P3 are connected to the high voltage point. The neutral conductor N is connected to ground. The device also includes a power supply 31 connected to the four conductors and a microprocessor 32 which, like the microprocessor 16, has at least one metrology function, i.e., measuring currents and voltages at various points and performing calculations based on these measurements. In this embodiment, a measuring resistor R3N (shunt) is mounted on the neutral connector N between the network 11 and the installation 33.The measuring resistor R3N allows the measurement of a current IN flowing through the neutral conductor N. On each phase connector PI, P2, and P3, respectively, are mounted a measuring transformer T1, T2, and T3, respectively, in series with a power relay XI, X2, and X3, respectively. The three power relays XI, X2, and X3 serve to disconnect the installation 33 from the network 11. They are controlled by the same command C provided by the microcontroller 32. As described previously for the single-phase network, the resistors R31, R32, and R33 mounted on the secondary windings of the transformers T1, T2, and T3 allow the current flowing through each of the phase connectors PI, P2, and P3 to be obtained. Figure [Fig. 3] also shows the bypasses BPI, BP2, BP3, and BN for the four conductors.
[0030] In addition to the metrological functions mentioned above, the microprocessor shown in Figures [Fig. 1] to [Fig. 3] can be configured to implement the fraud detection by bypass method described below. It is also possible to use a separate application microprocessor to implement the fraud detection functions based on data provided by the metrological microprocessor.
[0031] An example of an implementation of an algorithm for a fraud detection method by circumvention according to this disclosure is shown in Figure [Fig. 4]. This algorithm uses a first current threshold, denoted Q1, equal for example to 500 mA, and a second current threshold, denoted Q2, equal for example to 250 mA. In one embodiment, the values of the current thresholds Q1 and Q2 are programmable. The algorithm starts at step 40, with the power relay(s) XI to X3 closed. At step 41, a predetermined waiting time, for example Ih, is applied. This waiting phase is intended to prevent the power relay(s) from opening too frequently in production mode. At step 42, it is determined whether the installation is operating in production mode. Production mode is detected when the total active power associated with the phase conductor(s) is negative (i.e., the sum of the active powers on each phase). Advantageously, at step 43, it is verified that production mode is established, for example, that the installation has been operating in production mode for a certain time, for example, 60 seconds. If the total active power is not negative for a sufficient duration (60 seconds in this example), the algorithm resumes at step 42. Otherwise, it continues at step 44.Step 44 is optional, particularly advantageous in the case of a polyphase network. In step 44, it is checked whether the current flowing through the neutral conductor IN is greater than the first threshold Q1. For example, this can be done by checking if the first threshold Q1 is reached at least once over a period of, for example, 10 seconds. If not, the algorithm restarts in step 42. Otherwise, it continues in step 45. In step 45, a command is sent by the microprocessor to open the power relay(s). Then, in step 46, the maximum neutral current is measured. This can be done, for example, by determining a neutral current value every second and retaining the maximum value from among the ten measurements obtained. Then, in step 47, the power relay(s) are closed, and in step 48, it is checked whether the retained neutral current value is greater than the second threshold Q2.If no fraud is detected, the algorithm restarts at step 4L. Otherwise, at step 49, an alert is generated to be transmitted to the electricity network operator via a modem in the electrical device. The algorithm ends at step 50.
[0032] The specific structural and functional details described herein are non-limiting examples. They may be subject to various modifications, alternative forms, additions, or deletions without departing from the scope of disclosure as determined on the basis of the claims and their equivalents.
[0033] Any suitable data processing system can be used for implementation. A suitable data processing system or device includes, for example, a combination of software code and circuits, such as a processor, controller, or other circuit suitable for executing the software code. When the software code is executed, the processor or controller directs the system or device to implement all or part of the functionalities of the blocks and / or phases of the processes according to the embodiment examples. The software code can be stored in non-volatile memory or on a non-volatile storage medium (USB flash drive, card). memory or other medium) readable directly or through an interface adapted by the processor or controller.
[0034] For example, it is possible to use one or more microprocessor assemblies, for example a first microprocessor assembly responsible for the metrological functions of the meter (current and voltage measurement) in communication with a second microprocessor assembly responsible for the application functions of the meter, for example the implementation from the measurements provided by the first microprocessor of the fraud detection process by bypass as described here.
[0035] The advantages and solutions to problems have been described above with respect to specific embodiments of the invention. They should not be interpreted as a critical, required, or essential feature or element of any or all of the claims.
Claims
Demands
1. An electrical device intended to be mounted between an electrical network and an electrical installation, the electrical network comprising one or more phase conductors and a neutral conductor, and the electrical installation being configured to operate in energy consumption mode or in energy production mode, the device comprising a power relay on each phase conductor, mounted between the electrical network and the electrical installation, and at least one microprocessor assembly configured to perform the following operations: - determine that the electrical installation is operating in energy production mode, - open the power relay(s), - obtain a measurement of the current flowing in the neutral conductor, and - generate an alert based on said measurement.
2. Device according to claim 1, characterized in that at least one microprocessor assembly is configured to repeat said operations periodically until an alert has been generated.
3. Device according to any one of claims 1 or 2, characterized in that at least one microprocessor assembly is configured to calculate an overall active power associated with the phase conductor(s), and to determine that the electrical installation is operating in power production mode when the overall active power is negative for a predefined period.
4. Device according to any one of claims 1 to 3, characterized in that at least one microprocessor assembly is configured to, before opening the power relay(s), verify that the current flowing on the neutral conductor is above a first threshold.
5. Device according to any one of claims 1 to 4, characterized in that at least one microprocessor assembly is configured to generate the alert when the current flowing in the neutral conductor is greater than a second threshold.
6. A method for detecting fraud by bypassing an electrical installation connected to an electrical network via an electricity meter, the electrical network comprising one or more phase conductors and a neutral conductor, the installation electrical being configured to operate in energy consumption mode or in energy production mode, and the meter having a power relay on each phase conductor, characterized in that it includes the following operations: - a determination of the operation of the installation in energy producer mode, - an opening of the power relay(s), - a measurement of the current flowing in the neutral conductor, and - an alert generation based on said measurement.
7. A method according to claim 6, characterized in that said operations are repeated periodically until an alert has been generated.
8. A method according to any one of claims 6 or 7, characterized in that it comprises a calculation of an overall active power associated with the phase conductor(s), and in that said determination is made when the overall active power is negative for a predefined period.
9. A method according to any one of claims 6 to 8, characterized in that the opening of the power relay(s) takes place after verification that the current flowing on the neutral conductor is greater than a first threshold.
10. A method according to any one of claims 6 to 9, characterized in that the alert is generated when the current flowing in the neutral conductor is greater than a second threshold.
11. Product computer program comprising instructions which, when executed by at least one processor, cause the implementation of a process according to any one of claims 6 to 10.
12. Computer-readable non-transient storage medium comprising instructions which, when executed by a processor, cause the implementation of a method according to any one of claims 6 to 10.