Buckle type three-phase electric energy meter comprehensive error measuring device and method

Abstract

The invention discloses a buckle type three-phase electric energy meter comprehensive error measurement device and method, and the device comprises a buckle type signal collection module which is detachably connected with a voltage interface and a current interface of a three-phase electric energy meter through an insulating buckle structure, and is used for synchronously collecting a voltage signal and a current signal of the three-phase electric energy meter; the standard signal generation module generates a three-phase standard voltage signal and a three-phase standard current signal which meet national standard requirements; the error analyzing and processing module is used for determining the comprehensive error of the three-phase electric energy meter according to the voltage signal, the current signal, the three-phase standard voltage signal and the three-phase standard current signal of the three-phase electric energy meter; the comprehensive error is the sum value of the basic error and the additional error caused by the harmonic component. The insulating buckle structure is detachably connected with the voltage interface and the current interface of the three-phase electric energy meter, so that the installation time is shortened. By introducing the calculation of the additional error caused by the harmonic component, the accuracy of determining the comprehensive error of the three-phase electric energy meter is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of error measurement, and in particular to a snap-on three-phase electric energy meter comprehensive error measurement device and method. Background Art

[0002] In the current field of electricity meter error measurement, most traditional calibration devices use complex wiring methods when connecting to three-phase electricity meters. This is not only cumbersome and time-consuming to install, but also poses certain safety risks. Existing devices are not comprehensive in error analysis, often focusing only on the basic errors of the electricity meter and ignoring the impact of harmonics, which are prevalent in actual power grids, on electricity metering. In actual power grids, due to the extensive use of industrial loads and variable-frequency equipment, harmonic pollution is relatively severe. Harmonics can cause additional errors in electricity meters. Failure to account for these errors will result in an inaccurate assessment of the electricity meter's comprehensive error and fail to truly reflect the meter's performance under actual operating conditions. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems in the above-mentioned technologies to a certain extent. To this end, the purpose of the present invention is to propose a snap-on three-phase electric energy meter comprehensive error measurement device and method, which is detachably connected to the voltage interface and current interface of the three-phase electric energy meter through an insulating snap-on structure, greatly simplifying the connection process with the electric energy meter, eliminating the need for professional tools and complex wiring operations, significantly shortening the installation time, effectively avoiding the operator's contact with high-voltage signals, and improving the safety of on-site measurements. By introducing the calculation of the additional error caused by the harmonic component, the error of the electric energy meter is evaluated in a more appropriate manner for the actual power grid environment, thereby improving the accuracy of determining the comprehensive error of the three-phase electric energy meter.

[0004] To achieve the above objectives, an embodiment of the present invention provides a snap-on three-phase electric energy meter comprehensive error measurement device, comprising: The snap-on signal acquisition module uses an insulating snap-on structure to detachably connect to the voltage and current interfaces of the three-phase energy meter, and is used to synchronously acquire the voltage and current signals of the three-phase energy meter; Standard signal generation module, used to generate three-phase standard voltage signals and three-phase standard current signals that meet national standards; The error analysis and processing module is connected to the snap-on signal acquisition module and the standard signal generation module respectively, and determines the comprehensive error of the three-phase electric energy meter based on the voltage signal, current signal, three-phase standard voltage signal and three-phase standard current signal of the three-phase electric energy meter; the comprehensive error is the sum of the basic error and the additional error caused by the harmonic component.

[0005] According to some embodiments of the present invention, the snap-on signal acquisition module includes a snap-on voltage probe, a snap-on current probe, a noise reduction module, an analog-to-digital conversion module, and a temperature compensation module; wherein, Snap-on voltage probe, used to collect analog voltage signals from three-phase electric energy meters based on differential amplifier circuit; Snap-on current probe, used to collect analog current signals from three-phase energy meters; A noise reduction module is used to perform noise reduction processing on the analog voltage signal and the analog current signal to obtain a noise-reduced voltage signal and a noise-reduced current signal; An analog-to-digital conversion module is used to perform analog-to-digital conversion on the noise reduction voltage signal and the noise reduction current signal to obtain a digital voltage signal and a digital current signal; The temperature compensation module is used to monitor the ambient temperature in real time through a temperature sensor, query the preset temperature-compensation coefficient data table based on the ambient temperature, and obtain the compensation coefficient; based on the compensation coefficient, dynamically correct the digital voltage signal and digital current signal to obtain the voltage signal and current signal of the three-phase electric energy meter.

[0006] According to some embodiments of the present invention, the standard signal generation module adopts a signal source architecture based on direct digital synthesis technology to simulate the power grid environment. Based on the built-in voltage transformer and current transformer, phase control is performed through the FPGA chip to generate three-phase standard voltage signals and three-phase standard current signals that meet national standards.

[0007] According to some embodiments of the present invention, the error analysis and processing module includes: The first calculation module is used to perform spectrum analysis on the voltage signal and current signal of the three-phase electric energy meter based on fast Fourier transform, separate the fundamental component and the harmonic component, and calculate the additional error caused by the harmonic component; A comparison module is used to establish an actual amplitude-phase model of the voltage signal and current signal of the three-phase electric energy meter based on the least squares method; establish a standard amplitude-phase model of the three-phase standard voltage signal and the three-phase standard current signal based on the least squares method; establish a correspondence between the actual amplitude-phase model and the standard amplitude-phase model, and perform point-to-point comparison based on the correspondence to obtain a basic error; The second calculation module is used to calculate the sum of the additional error and the basic error, and use the sum as the comprehensive error of the three-phase electric energy meter.

[0008] According to some embodiments of the present invention, the first computing module includes: A separation module is used to perform spectrum analysis on the voltage and current signals of the three-phase electric energy meter based on fast Fourier transform, and separate the fundamental component and harmonic component of each phase voltage, and the fundamental component and harmonic component of each phase current; The first determination module is used to determine the fundamental power of each phase according to the fundamental component of each phase voltage and the fundamental component of each phase current and sum the sum to obtain the total fundamental power; and determine the fundamental electric energy based on the total fundamental power and the measurement time; A second determination module is configured to determine the harmonic power of each phase based on the harmonic components of the voltage of each phase and the harmonic components of the current of each phase, obtain the total active power based on the sum of the sum of the harmonic powers of each phase and the total power of the fundamental wave; and determine the total electric energy based on the total active power and the measurement time; The third determining module is used to calculate the difference between the total electric energy and the fundamental electric energy, and determine the ratio of the difference to the fundamental electric energy as the additional error caused by the harmonic component.

[0009] According to some embodiments of the present invention, the comparison module includes: The fourth determining module is configured to: Establishing an actual amplitude-phase model of the voltage signal of the three-phase electric energy meter and an actual amplitude-phase model of the current signal of the three-phase electric energy meter based on the least squares method; in, is the actual amplitude-phase model of the voltage signal of the three-phase electric energy meter; is the actual amplitude-phase model of the current signal of the three-phase electric energy meter; 、 are the voltage amplitude and current amplitude of the i-th harmonic based on the least squares fitting method; 、 are the voltage phase and current phase of the i-th harmonic based on the least squares fitting method; is the number of harmonics; is the angular frequency; is the time variable; Determine the standard voltage amplitude and standard current amplitude of the i-th harmonic of the standard amplitude-phase model based on the least squares method; Establish a module for establishing the correspondence between the actual amplitude-phase model and the standard amplitude-phase model, perform point-to-point comparison based on the correspondence, and determine the voltage amplitude error and current amplitude error of each harmonic; The average value of the sum of the products of the voltage amplitude error and the current amplitude error of each harmonic is taken as the basic error.

[0010] According to some embodiments of the present invention, it also includes: a monitoring module for monitoring the connection status of the snap-on signal acquisition module and the output status of the signal source. When poor contact or signal distortion is detected, the measurement is automatically suspended and an audible and visual alarm is issued, and the fault code and the time when the fault occurred are recorded.

[0011] According to some embodiments of the present invention, the system further includes: a recording module for recording the comprehensive error and timestamp information of the three-phase electric energy meter, and displaying the error trend curve in real time using a graphical interface.

[0012] According to some embodiments of the present invention, the monitoring module is used to monitor the contact pressure between the snap-on signal acquisition module and the three-phase electric energy meter through a pressure sensor. When the pressure value is lower than a preset threshold, poor contact is determined and an early warning is issued.

[0013] According to some embodiments of the present invention, a measurement method of the aforementioned snap-on three-phase electric energy meter comprehensive error measurement device includes: Synchronously collect voltage and current signals of three-phase electric energy meters; Generate three-phase standard voltage signal and three-phase standard current signal that meet national standards; The comprehensive error of the three-phase electric energy meter is determined based on the voltage signal, current signal, three-phase standard voltage signal and three-phase standard current signal of the three-phase electric energy meter; the comprehensive error is the sum of the basic error and the additional error caused by the harmonic component.

[0014] This invention proposes a snap-on three-phase electric energy meter comprehensive error measurement device and method. Through an insulated snap-on structure, the device detachably connects to the voltage and current interfaces of the three-phase electric energy meter. This greatly simplifies the connection process to the electric energy meter, eliminating the need for specialized tools and complex wiring operations. This significantly shortens installation time, effectively prevents operators from being exposed to high-voltage signals, and improves the safety of on-site measurements. By incorporating the calculation of the additional error caused by harmonic components, the device evaluates the electric energy meter's error in a more realistic grid environment, improving the accuracy of determining the comprehensive error of the three-phase electric energy meter.

[0015] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0016] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 is a block diagram of a snap-on three-phase electric energy meter comprehensive error measurement device according to one embodiment of the present invention; Figure 2 is a block diagram of a snap-on signal acquisition module according to one embodiment of the present invention; Figure 3 The present invention is a flowchart of a method for measuring a comprehensive error of a snap-on three-phase electric energy meter according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0019] like Figure 1 As shown, the embodiment of the present invention provides a snap-on three-phase electric energy meter comprehensive error measurement device, comprising: The snap-on signal acquisition module uses an insulating snap-on structure to detachably connect to the voltage and current interfaces of the three-phase energy meter, and is used to synchronously acquire the voltage and current signals of the three-phase energy meter; Standard signal generation module, used to generate three-phase standard voltage signals and three-phase standard current signals that meet national standards; The error analysis and processing module is connected to the snap-on signal acquisition module and the standard signal generation module respectively, and determines the comprehensive error of the three-phase electric energy meter based on the voltage signal, current signal, three-phase standard voltage signal and three-phase standard current signal of the three-phase electric energy meter; the comprehensive error is the sum of the basic error and the additional error caused by the harmonic component.

[0020] The working principle of the above technical solution is as follows: Based on the snap-on signal acquisition module, an insulating snap-on structure is used to detachably connect to the voltage and current interfaces of the three-phase electricity meter, synchronously acquiring the voltage and current signals of the three-phase electricity meter; based on the standard signal generation module, the measurement environment is simulated to generate a three-phase standard voltage signal and a three-phase standard current signal that meet the requirements of the national standard; based on the voltage signal, current signal, three-phase standard voltage signal, and three-phase standard current signal of the three-phase electricity meter, the comprehensive error of the three-phase electricity meter is determined; the comprehensive error is the sum of the basic error and the additional error caused by the harmonic components. The basic error is determined based on the voltage signal, current signal, three-phase standard voltage signal, and three-phase standard current signal. The average of the sum of the product of the voltage amplitude error and the current amplitude error of each harmonic is used as the basic error.

[0021] The beneficial effects of this technical solution include: The insulated snap-on structure allows for detachable connection to the voltage and current interfaces of a three-phase meter, greatly simplifying the meter connection process. This eliminates the need for specialized tools and complex wiring, significantly shortening installation time, effectively preventing operators from being exposed to high-voltage signals, and improving on-site measurement safety. By incorporating calculations for additional errors caused by harmonic components, the meter's error is assessed more accurately in accordance with actual grid conditions, improving the accuracy of determining the comprehensive error of three-phase meters.

[0022] like Figure 2 As shown, according to some embodiments of the present invention, the snap-on signal acquisition module includes a snap-on voltage probe, a snap-on current probe, a noise reduction module, an analog-to-digital conversion module, and a temperature compensation module; wherein, Snap-on voltage probe, used to collect analog voltage signals from three-phase electric energy meters based on differential amplifier circuit; Snap-on current probe, used to collect analog current signals from three-phase energy meters; A noise reduction module is used to perform noise reduction processing on the analog voltage signal and the analog current signal to obtain a noise-reduced voltage signal and a noise-reduced current signal; An analog-to-digital conversion module is used to perform analog-to-digital conversion on the noise reduction voltage signal and the noise reduction current signal to obtain a digital voltage signal and a digital current signal; The temperature compensation module is used to monitor the ambient temperature in real time through a temperature sensor, query the preset temperature-compensation coefficient data table based on the ambient temperature, and obtain the compensation coefficient; based on the compensation coefficient, dynamically correct the digital voltage signal and digital current signal to obtain the voltage signal and current signal of the three-phase electric energy meter.

[0023] The working principle and beneficial effects of the above technical solution are as follows: Using a snap-on voltage probe and a snap-on current probe to synchronously collect the analog voltage and current signals of a three-phase electricity meter, a noise reduction module is used to perform noise reduction processing to eliminate the influence of noise. Using an analog-to-digital conversion module, the noise-reduced voltage and current signals are converted into digital voltage and current signals. Temperature compensation is performed on the digital voltage and current signals using a temperature compensation module, improving the accuracy of determining the voltage and current signals of the three-phase electricity meter.

[0024] According to some embodiments of the present invention, the standard signal generation module adopts a signal source architecture based on direct digital synthesis technology to simulate the power grid environment. Based on the built-in voltage transformer and current transformer, phase control is performed through the FPGA chip to generate three-phase standard voltage signals and three-phase standard current signals that meet national standards.

[0025] The working principle and beneficial effects of the above technical solution: The signal source architecture of the direct digital synthesis technology includes a phase accumulator, a waveform lookup table (ROM), a digital-to-analog converter (DAC) and a low-pass filter to achieve phase control, waveform generation and digital-to-analog conversion. FPGA is a field programmable gate array, which undertakes the functions of real-time phase regulation and power grid operating condition simulation, including static phase calibration, dynamic operating condition simulation and synchronous control. Based on the built-in voltage transformer and current transformer, it undertakes the signal conversion and isolation functions, including signal scaling and electrical isolation. Through the combination of digital technology and power transformers, high-precision and high-flexibility simulation of the power grid environment is achieved, and the signal accuracy and stability are greatly improved, which facilitates the accurate generation of three-phase standard voltage signals and three-phase standard current signals that meet the national standards, determines a reliable reference standard, and facilitates the improvement of the accuracy of error calculation.

[0026] According to some embodiments of the present invention, the error analysis and processing module includes: The first calculation module is used to perform spectrum analysis on the voltage signal and current signal of the three-phase electric energy meter based on fast Fourier transform, separate the fundamental component and the harmonic component, and calculate the additional error caused by the harmonic component; A comparison module is used to establish an actual amplitude-phase model of the voltage signal and current signal of the three-phase electric energy meter based on the least squares method; establish a standard amplitude-phase model of the three-phase standard voltage signal and the three-phase standard current signal based on the least squares method; establish a correspondence between the actual amplitude-phase model and the standard amplitude-phase model, and perform point-to-point comparison based on the correspondence to obtain a basic error; The second calculation module is used to calculate the sum of the additional error and the basic error, and use the sum as the comprehensive error of the three-phase electric energy meter.

[0027] The working principle and beneficial effects of the above technical solution are as follows: Based on the fast Fourier transform, the voltage and current signals of the three-phase electricity meter are spectrally analyzed to separate the fundamental component and the harmonic component, and the additional error caused by the harmonic component is calculated; the actual amplitude-phase model of the voltage and current signals of the three-phase electricity meter is established based on the least squares method; the voltage amplitude and voltage phase, and the current amplitude and current phase of the corresponding actual amplitude-phase model are determined based on the least squares method. The standard amplitude-phase model of the three-phase standard voltage signal and the three-phase standard current signal is established based on the least squares method; the standard voltage amplitude and standard voltage phase, and the standard current amplitude and standard current phase of the corresponding standard amplitude-phase model are determined based on the least squares method. When calculating the basic error, the influence of the phase error is ignored, and the basic error is calculated based on the amplitude error. A correspondence between the actual amplitude-phase model and the standard amplitude-phase model is established, and a point-to-point comparison is performed based on the correspondence. The basic error is calculated based on the voltage amplitude error and the current amplitude error of each harmonic. The sum of the additional error and the basic error is calculated and used as the comprehensive error of the three-phase electric energy meter, thereby improving the accuracy of the comprehensive error.

[0028] According to some embodiments of the present invention, the first computing module includes: A separation module is used to perform spectrum analysis on the voltage and current signals of the three-phase electric energy meter based on fast Fourier transform, and separate the fundamental component and harmonic component of each phase voltage, and the fundamental component and harmonic component of each phase current; The first determination module is used to determine the fundamental power of each phase according to the fundamental component of each phase voltage and the fundamental component of each phase current and sum the sum to obtain the total fundamental power; and determine the fundamental electric energy based on the total fundamental power and the measurement time; A second determination module is configured to determine the harmonic power of each phase based on the harmonic components of the voltage of each phase and the harmonic components of the current of each phase, obtain the total active power based on the sum of the sum of the harmonic powers of each phase and the total power of the fundamental wave; and determine the total electric energy based on the total active power and the measurement time; The third determining module is used to calculate the difference between the total electric energy and the fundamental electric energy, and determine the ratio of the difference to the fundamental electric energy as the additional error caused by the harmonic component.

[0029] The working principle and beneficial effects of the above technical solution are as follows: Based on the fast Fourier transform, the voltage and current signals of the three-phase electric energy meter are spectrally analyzed to separate the fundamental and harmonic components of each phase voltage and the fundamental and harmonic components of each phase current; the fundamental power of each phase is determined based on the fundamental component of each phase voltage and the fundamental component of each phase current, and the sum is calculated as the total fundamental power; the fundamental electric energy is determined based on the total fundamental power and the measurement time; the harmonic power of each phase is determined based on the harmonic component of each phase voltage and the harmonic component of each phase current, and the total active power is obtained by summing the sum of the harmonic power of each phase and the total fundamental power; the total electric energy is determined based on the total active power and the measurement time; the difference between the total electric energy and the fundamental electric energy is calculated, and the ratio of the difference to the fundamental electric energy is determined as the additional error caused by the harmonic component. This fully considers the impact of the additional error caused by the harmonic component on the comprehensive error measurement, improving the accuracy of the additional error determination.

[0030] According to some embodiments of the present invention, the comparison module includes: The fourth determining module is configured to: Establishing an actual amplitude-phase model of the voltage signal of the three-phase electric energy meter and an actual amplitude-phase model of the current signal of the three-phase electric energy meter based on the least squares method; in, is the actual amplitude-phase model of the voltage signal of the three-phase electric energy meter; is the actual amplitude-phase model of the current signal of the three-phase electric energy meter; 、 are the voltage amplitude and current amplitude of the i-th harmonic based on the least squares fitting method; 、 are the voltage phase and current phase of the i-th harmonic based on the least squares fitting method; is the number of harmonics; is the angular frequency; is the time variable; Determine the standard voltage amplitude and standard current amplitude of the i-th harmonic of the standard amplitude-phase model based on the least squares method; Establish a module for establishing the correspondence between the actual amplitude-phase model and the standard amplitude-phase model, perform point-to-point comparison based on the correspondence, and determine the voltage amplitude error and current amplitude error of each harmonic; The average value of the sum of the products of the voltage amplitude error and the current amplitude error of each harmonic is taken as the basic error.

[0031] The working principle and beneficial effects of the above technical solution are as follows: Based on the least squares method, an actual amplitude-phase model of the voltage signal and an actual amplitude-phase model of the current signal of the three-phase electric energy meter are established. The voltage amplitude, current amplitude, voltage phase, and current phase of the i-th harmonic of the actual amplitude-phase model are determined based on least squares fitting. Based on the same principle, the standard voltage amplitude and standard current amplitude of the i-th harmonic of the standard amplitude-phase model are determined. A correspondence between the actual amplitude-phase model and the standard amplitude-phase model is established, and a point-to-point comparison is performed based on the correspondence to determine the voltage amplitude error and current amplitude error of each harmonic. The voltage amplitude error is calculated by calculating the difference between the voltage amplitude of the i-th harmonic of the actual amplitude-phase model and the standard voltage amplitude, and the ratio of the difference to the standard voltage amplitude is used as the voltage amplitude error. The current amplitude error is calculated by calculating the difference between the current amplitude of the i-th harmonic of the actual amplitude-phase model and the standard current amplitude, and the ratio of the difference to the standard current amplitude is used as the current amplitude error. The average value of the sum of the product of the voltage amplitude error and the current amplitude error of each harmonic is taken as the basic error. This facilitates accurate calculation of the basic error and thus improves the accuracy of determining the comprehensive error.

[0032] According to some embodiments of the present invention, it also includes: a monitoring module for monitoring the connection status of the snap-on signal acquisition module and the output status of the signal source. When poor contact or signal distortion is detected, the measurement is automatically suspended and an audible and visual alarm is issued, and the fault code and the time when the fault occurred are recorded.

[0033] The working principle and beneficial effects of the above technical solution: During the error measurement process, the monitoring module monitors the connection status of the snap-on signal acquisition module and the output status of the signal source. When poor contact or signal distortion is detected, the measurement is automatically paused and an audible and visual alarm is issued. At the same time, the fault code and the time of occurrence of the fault are recorded, so as to facilitate the timely discovery of abnormalities in the error measurement process and ensure the effective implementation of the error measurement.

[0034] According to some embodiments of the present invention, the system further includes: a recording module for recording the comprehensive error and timestamp information of the three-phase electric energy meter, and displaying the error trend curve in real time using a graphical interface.

[0035] The working principle and beneficial effects of the above technical solution are as follows: the comprehensive error and timestamp information of the three-phase electricity meter are recorded based on the recording module, and the error trend curve is displayed in real time using a graphical interface, which facilitates the display and analysis of the comprehensive error of the measurement.

[0036] According to some embodiments of the present invention, the monitoring module is used to monitor the contact pressure between the snap-on signal acquisition module and the three-phase electric energy meter through a pressure sensor. When the pressure value is lower than a preset threshold, poor contact is determined and an early warning is issued.

[0037] The working principle and beneficial effects of the above technical solution: The monitoring module is used to monitor the contact pressure between the snap-on signal acquisition module and the three-phase electric energy meter through a pressure sensor. When the pressure value is lower than the preset threshold, poor contact is determined and an early warning is issued, which facilitates the monitoring of the connection status between the snap-on signal acquisition module and the three-phase electric energy meter to ensure the effective error measurement.

[0038] like Figure 3 As shown, according to some embodiments of the present invention, the measurement method of the above-mentioned snap-on three-phase electric energy meter comprehensive error measurement device includes steps S1-S3: S1, synchronously collect voltage and current signals of three-phase electric energy meters; S2. Generate three-phase standard voltage signal and three-phase standard current signal that meet national standards; S3. Determine a comprehensive error of the three-phase electric energy meter based on the voltage signal, current signal, three-phase standard voltage signal, and three-phase standard current signal of the three-phase electric energy meter; the comprehensive error is the sum of the basic error and the additional error caused by the harmonic component.

[0039] The beneficial effects of this technical solution include: The insulated snap-on structure allows for detachable connection to the voltage and current interfaces of a three-phase meter, greatly simplifying the meter connection process. This eliminates the need for specialized tools and complex wiring, significantly shortening installation time, effectively preventing operators from being exposed to high-voltage signals, and improving on-site measurement safety. By incorporating calculations for additional errors caused by harmonic components, the meter's error is assessed more accurately in accordance with actual grid conditions, improving the accuracy of determining the comprehensive error of three-phase meters.

[0040] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A snap-on three-phase electric energy meter comprehensive error measuring device, characterized in that: include: The snap-on signal acquisition module uses an insulating snap-on structure to detachably connect to the voltage and current interfaces of the three-phase energy meter, and is used to synchronously acquire the voltage and current signals of the three-phase energy meter; Standard signal generation module, used to generate three-phase standard voltage signals and three-phase standard current signals that meet national standards; The error analysis and processing module is connected to the snap-on signal acquisition module and the standard signal generation module respectively, and determines the comprehensive error of the three-phase electric energy meter based on the voltage signal, current signal, three-phase standard voltage signal and three-phase standard current signal of the three-phase electric energy meter; the comprehensive error is the sum of the basic error and the additional error caused by the harmonic component.

2. The snap-on three-phase electric energy meter comprehensive error measuring device according to claim 1, characterized in that: The snap-on signal acquisition module includes a snap-on voltage probe, a snap-on current probe, a noise reduction module, an analog-to-digital conversion module, and a temperature compensation module; Snap-on voltage probe, used to collect analog voltage signals from three-phase electric energy meters based on differential amplifier circuit; Snap-on current probe, used to collect analog current signals from three-phase energy meters; A noise reduction module is used to perform noise reduction processing on the analog voltage signal and the analog current signal to obtain a noise-reduced voltage signal and a noise-reduced current signal; An analog-to-digital conversion module is used to perform analog-to-digital conversion on the noise reduction voltage signal and the noise reduction current signal to obtain a digital voltage signal and a digital current signal; The temperature compensation module is used to monitor the ambient temperature in real time through a temperature sensor, query the preset temperature-compensation coefficient data table based on the ambient temperature, and obtain the compensation coefficient; based on the compensation coefficient, dynamically correct the digital voltage signal and digital current signal to obtain the voltage signal and current signal of the three-phase electric energy meter.

3. The snap-on three-phase electric energy meter comprehensive error measuring device according to claim 1, characterized in that: The standard signal generation module adopts a signal source architecture based on direct digital synthesis technology to simulate the power grid environment. Based on the built-in voltage transformer and current transformer, it performs phase control through the FPGA chip to generate three-phase standard voltage signals and three-phase standard current signals that meet national standards.

4. The snap-on three-phase electric energy meter comprehensive error measuring device according to claim 1, characterized in that: Error analysis and processing module, including: The first calculation module is used to perform spectrum analysis on the voltage signal and current signal of the three-phase electric energy meter based on fast Fourier transform, separate the fundamental component and the harmonic component, and calculate the additional error caused by the harmonic component; A comparison module is used to establish an actual amplitude-phase model of the voltage signal and current signal of the three-phase electric energy meter based on the least squares method; establish a standard amplitude-phase model of the three-phase standard voltage signal and the three-phase standard current signal based on the least squares method; establish a correspondence between the actual amplitude-phase model and the standard amplitude-phase model, and perform point-to-point comparison based on the correspondence to obtain a basic error; The second calculation module is used to calculate the sum of the additional error and the basic error, and use the sum as the comprehensive error of the three-phase electric energy meter.

5. The snap-on three-phase electric energy meter comprehensive error measuring device according to claim 4, characterized in that: The first computing module includes: A separation module is used to perform spectrum analysis on the voltage and current signals of the three-phase electric energy meter based on fast Fourier transform, and separate the fundamental component and harmonic component of each phase voltage, and the fundamental component and harmonic component of each phase current; The first determination module is used to determine the fundamental power of each phase according to the fundamental component of each phase voltage and the fundamental component of each phase current and sum the sum to obtain the total fundamental power; and determine the fundamental electric energy based on the total fundamental power and the measurement time; A second determination module is configured to determine the harmonic power of each phase based on the harmonic components of the voltage of each phase and the harmonic components of the current of each phase, obtain the total active power based on the sum of the sum of the harmonic powers of each phase and the total power of the fundamental wave; and determine the total electric energy based on the total active power and the measurement time; The third determining module is used to calculate the difference between the total electric energy and the fundamental electric energy, and determine the ratio of the difference to the fundamental electric energy as the additional error caused by the harmonic component.

6. The snap-on three-phase electric energy meter comprehensive error measuring device according to claim 4, characterized in that: Comparison module, including: The fourth determining module is configured to: Establishing an actual amplitude-phase model of the voltage signal of the three-phase electric energy meter and an actual amplitude-phase model of the current signal of the three-phase electric energy meter based on the least squares method; in, is the actual amplitude-phase model of the voltage signal of the three-phase electric energy meter; is the actual amplitude-phase model of the current signal of the three-phase electric energy meter; 、 are the voltage amplitude and current amplitude of the i-th harmonic based on the least squares fitting method; 、 are the voltage phase and current phase of the i-th harmonic based on the least squares fitting method; is the number of harmonics; is the angular frequency; is the time variable; Determine the standard voltage amplitude and standard current amplitude of the i-th harmonic of the standard amplitude-phase model based on the least squares method; Establish a module for establishing the correspondence between the actual amplitude-phase model and the standard amplitude-phase model, perform point-to-point comparison based on the correspondence, and determine the voltage amplitude error and current amplitude error of each harmonic; The average value of the sum of the products of the voltage amplitude error and the current amplitude error of each harmonic is taken as the basic error.

7. The snap-on three-phase electric energy meter comprehensive error measuring device according to claim 1, characterized in that: Also includes: The monitoring module is used to monitor the connection status of the snap-on signal acquisition module and the output status of the signal source. When poor contact or signal distortion is detected, the module automatically pauses the measurement and issues an audible and visual alarm, while also recording the fault code and the time when the fault occurred.

8. The snap-on three-phase electric energy meter comprehensive error measuring device according to claim 1, characterized in that: Also includes: The recording module is used to record the comprehensive error and timestamp information of the three-phase electricity meter, and display the error trend curve in real time using a graphical interface.

9. The snap-on three-phase electric energy meter comprehensive error measuring device according to claim 7, characterized in that: The monitoring module is used to monitor the contact pressure between the snap-on signal acquisition module and the three-phase electric energy meter through a pressure sensor. When the pressure value is lower than the preset threshold, poor contact is determined and an early warning is issued.

10. The measuring method of the snap-on type three-phase electric energy meter comprehensive error measuring device according to any one of claims 1 to 9, characterized in that: include: Synchronously collect voltage and current signals of three-phase electric energy meters; Generate three-phase standard voltage signal and three-phase standard current signal that meet national standards; The comprehensive error of the three-phase electric energy meter is determined based on the voltage signal, current signal, three-phase standard voltage signal and three-phase standard current signal of the three-phase electric energy meter; the comprehensive error is the sum of the basic error and the additional error caused by the harmonic component.

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