Synthetic error measuring device and method for snap-type three-phase electric energy meter

Abstract

This invention discloses a snap-on type three-phase energy meter comprehensive error measurement device and method, comprising: a snap-on signal acquisition module, which adopts an insulated snap-on structure and is detachably connected to the voltage and current interfaces of the three-phase energy meter for synchronously acquiring the voltage and current signals of the three-phase energy meter; a standard signal generation module that generates three-phase standard voltage and current signals conforming to national standards; and an error analysis and processing module that determines the comprehensive error of the three-phase energy meter based on the voltage signal, current signal, three-phase standard voltage signal, and three-phase standard current signal of the three-phase energy meter; wherein the comprehensive error is the sum of the basic error and the additional error caused by harmonic components. The detachable connection of the insulated snap-on structure to the voltage and current interfaces of the three-phase energy meter shortens the installation time. By introducing the calculation of the additional error caused by harmonic components, the accuracy of determining the comprehensive error of the three-phase energy meter is improved.

Description

Technical Field

[0001] This invention relates to the field of error measurement technology, and in particular to a snap-on three-phase energy meter comprehensive error measurement device and method. Background Technology

[0002] In the current field of electricity meter error measurement, most traditional calibration devices employ complex wiring methods when connecting to three-phase electricity meters. This not only results in cumbersome installation and significant time consumption but also poses certain safety risks. Existing devices lack comprehensive error analysis, often focusing only on the basic error of the electricity meter while neglecting the impact of harmonics, which are prevalent in the actual power grid, on electricity metering. In actual power grids, due to the extensive use of industrial loads and frequency converters, harmonic pollution is severe. Harmonics can cause additional errors in electricity meters. Ignoring these errors will lead to inaccurate assessments of the overall error of the electricity meter, failing to truly reflect its metering performance under actual operating conditions. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in the aforementioned technologies. Therefore, the purpose of this invention is to propose a snap-on type three-phase energy meter comprehensive error measurement device and method. Through an insulating snap-on structure, it can be detachably connected to the voltage and current interfaces of the three-phase energy meter, greatly simplifying the connection process. It eliminates the need for specialized tools and complex wiring operations, significantly shortening installation time, effectively preventing operators from coming into contact with high-voltage signals, and improving the safety of on-site measurements. By introducing the calculation of additional errors caused by harmonic components, it more closely reflects the actual power grid environment to evaluate the energy meter's error, improving the accuracy of determining the comprehensive error of the three-phase energy meter.

[0004] To achieve the above objectives, this invention provides a snap-on type three-phase energy meter comprehensive error measurement device, comprising:

[0005] The snap-on signal acquisition module uses an insulated 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.

[0006] The standard signal generation module is used to generate three-phase standard voltage signals and three-phase standard current signals that meet national standards.

[0007] The error analysis and processing module is connected to the snap-on signal acquisition module and the standard signal generation module respectively. Based on the voltage signal, current signal, three-phase standard voltage signal and three-phase standard current signal of the three-phase energy meter, the comprehensive error of the three-phase energy meter is determined. The comprehensive error is the sum of the basic error and the additional error caused by the harmonic components.

[0008] 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,

[0009] Clip-on voltage probes are used to acquire analog voltage signals from three-phase energy meters based on differential amplifier circuits.

[0010] Clip-on current probes are used to collect analog current signals from three-phase energy meters.

[0011] The noise reduction module is used to perform noise reduction processing on analog voltage signals and analog current signals to obtain noise-reduced voltage signals and noise-reduced current signals.

[0012] The analog-to-digital conversion module is used to perform analog-to-digital conversion on the noise-reduced voltage signal and the noise-reduced current signal to obtain the digital voltage signal and the digital current signal.

[0013] The temperature compensation module is used to monitor the ambient temperature in real time through a temperature sensor, query a preset temperature-compensation coefficient data table based on the ambient temperature to obtain the compensation coefficient, and dynamically correct the digital voltage signal and digital current signal based on the compensation coefficient to obtain the voltage signal and current signal of the three-phase energy meter.

[0014] 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, the module performs phase modulation through an FPGA chip to generate a three-phase standard voltage signal and a three-phase standard current signal that meet national standards.

[0015] According to some embodiments of the present invention, an error analysis processing module includes:

[0016] The first calculation module is used to perform spectrum analysis on the voltage and current signals of the three-phase energy meter based on the fast Fourier transform, separate the fundamental component and harmonic components, and calculate the additional error caused by the harmonic components.

[0017] The comparison module is used to establish the actual amplitude-phase model of the voltage and current signals of the three-phase energy meter based on the least squares method; to establish the standard amplitude-phase model of the three-phase standard voltage signal and the three-phase standard current signal based on the least squares method; to establish the correspondence between the actual amplitude-phase model and the standard amplitude-phase model; and to perform point-to-point comparison based on the correspondence to obtain the basic error.

[0018] The second calculation module is used to calculate the sum of the additional error and the basic error, and the sum is used as the comprehensive error of the three-phase energy meter.

[0019] According to some embodiments of the present invention, a first computing module includes:

[0020] The separation module is used to perform spectrum analysis on the voltage and current signals of a three-phase energy meter based on fast Fourier transform, separating the fundamental and harmonic components of each phase voltage and the fundamental and harmonic components of each phase current.

[0021] The first determining module is used to determine the fundamental power of each phase based on the fundamental components of the voltage and current of each phase, and sum the values ​​to obtain the total fundamental power; and determine the fundamental energy based on the total fundamental power and the measurement time.

[0022] The second determining module is used to determine the harmonic power of each phase based on the harmonic components of the voltage and the current of each phase, and to obtain the total active power by summing the harmonic power of each phase with the total fundamental power; and to determine the total electrical energy based on the total active power and the measurement time.

[0023] The third determining module is used to calculate the difference between the total electrical energy and the fundamental electrical energy, and the ratio of the difference to the fundamental electrical energy is determined as the additional error caused by the harmonic components.

[0024] According to some embodiments of the present invention, the comparison module includes:

[0025] The fourth determining module is used for:

[0026] The actual amplitude-phase model of the voltage signal and the actual amplitude-phase model of the current signal of the three-phase energy meter are established based on the least squares method.

[0027]

[0028]

[0029] in, This is the actual amplitude-phase model of the voltage signal of a three-phase energy meter; This is the actual amplitude-phase model of the current signal from a three-phase energy meter. , These represent the voltage amplitude and current amplitude of the i-th harmonic, respectively, fitted using the least squares method. , These are the voltage phase and current phase of the i-th harmonic, respectively, fitted using the least squares method. The number of harmonics; Angular frequency; It is a time variable;

[0030] The standard voltage amplitude and standard current amplitude of the i-th harmonic in the standard amplitude-phase model are determined based on the least squares method.

[0031] A module is established to establish the correspondence between the actual amplitude-phase model and the standard amplitude-phase model. Based on the correspondence, a point-to-point comparison is performed to determine the voltage amplitude error and current amplitude error of each harmonic.

[0032] The average 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.

[0033] According to some embodiments of the present invention, it further includes: a monitoring module for monitoring the connection status and signal source output status of the snap-on signal acquisition module, automatically pausing the measurement and issuing an audible and visual alarm when poor contact or signal distortion is detected, and simultaneously recording the fault code and the time of fault occurrence.

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

[0035] 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 energy meter through a pressure sensor. When the pressure value is lower than a preset threshold, it determines poor contact and issues an early warning.

[0036] According to some embodiments of the present invention, the measurement method of the snap-on three-phase energy meter comprehensive error measuring device as described above includes:

[0037] Simultaneously acquire voltage and current signals from three-phase energy meters;

[0038] Generate three-phase standard voltage signals and three-phase standard current signals that meet national standards;

[0039] The comprehensive error of the three-phase 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 energy meter; the comprehensive error is the sum of the basic error and the additional error caused by harmonic components.

[0040] This invention proposes a snap-on type three-phase energy meter comprehensive error measurement device and method. Through an insulated snap-on structure, it can be detachably connected to the voltage and current interfaces of the three-phase energy meter, greatly simplifying the connection process. It eliminates the need for specialized tools and complex wiring operations, significantly shortening installation time and effectively preventing operators from coming into contact with high-voltage signals, thus improving the safety of on-site measurements. By introducing the calculation of additional errors caused by harmonic components, it more closely reflects the actual power grid environment to evaluate the energy meter's error, improving the accuracy of determining the comprehensive error of the three-phase energy meter.

[0041] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0042] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0043] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0044] Figure 1 This is a block diagram of a snap-on three-phase energy meter comprehensive error measuring device according to an embodiment of the present invention;

[0045] Figure 2 This is a block diagram of a snap-on signal acquisition module according to an embodiment of the present invention;

[0046] Figure 3 This is a flowchart of a method for measuring the comprehensive error of a snap-on three-phase energy meter according to an embodiment of the present invention. Detailed Implementation

[0047] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0048] like Figure 1 As shown, this embodiment of the invention proposes a snap-on type three-phase energy meter comprehensive error measurement device, comprising:

[0049] The snap-on signal acquisition module uses an insulated 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.

[0050] The standard signal generation module is used to generate three-phase standard voltage signals and three-phase standard current signals that meet national standards.

[0051] The error analysis and processing module is connected to the snap-on signal acquisition module and the standard signal generation module respectively. Based on the voltage signal, current signal, three-phase standard voltage signal and three-phase standard current signal of the three-phase energy meter, the comprehensive error of the three-phase energy meter is determined. The comprehensive error is the sum of the basic error and the additional error caused by the harmonic components.

[0052] The working principle of the above technical solution is as follows: Based on a snap-on signal acquisition module, an insulated snap-on structure is used to detachably connect to the voltage and current interfaces of the three-phase energy meter, synchronously acquiring the voltage and current signals of the three-phase energy meter; based on a standard signal generation module, a simulated measurement environment is used to generate three-phase standard voltage and current signals that meet national standards; based on the voltage signal, current signal, three-phase standard voltage signal, and three-phase standard current signal of the three-phase energy meter, the comprehensive error of the three-phase energy meter is determined; the comprehensive error is the sum of the basic error and the additional error caused by 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, and the average value of the sum of the products of the voltage amplitude error and current amplitude error of each harmonic is taken as the basic error.

[0053] The beneficial effects of the above technical solution are as follows: The detachable connection between the insulated snap-fit ​​structure and the voltage and current interfaces of the three-phase energy meter greatly simplifies the connection process, eliminating the need for specialized tools and complex wiring operations, significantly shortening installation time, effectively preventing operators from coming into contact with high-voltage signals, and improving the safety of on-site measurements. By introducing the calculation of additional errors caused by harmonic components, the error of the energy meter is evaluated in a more realistic way, improving the accuracy of determining the overall error of the three-phase energy meter.

[0054] 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,

[0055] Clip-on voltage probes are used to acquire analog voltage signals from three-phase energy meters based on differential amplifier circuits.

[0056] Clip-on current probes are used to collect analog current signals from three-phase energy meters.

[0057] The noise reduction module is used to perform noise reduction processing on analog voltage signals and analog current signals to obtain noise-reduced voltage signals and noise-reduced current signals.

[0058] The analog-to-digital conversion module is used to perform analog-to-digital conversion on the noise-reduced voltage signal and the noise-reduced current signal to obtain the digital voltage signal and the digital current signal.

[0059] The temperature compensation module is used to monitor the ambient temperature in real time through a temperature sensor, query a preset temperature-compensation coefficient data table based on the ambient temperature to obtain the compensation coefficient, and dynamically correct the digital voltage signal and digital current signal based on the compensation coefficient to obtain the voltage signal and current signal of the three-phase energy meter.

[0060] The working principle and beneficial effects of the above technical solution are as follows: Analog voltage and current signals from a three-phase energy meter are simultaneously acquired using snap-on voltage and current probes. Noise reduction is performed using a noise reduction module to eliminate noise interference. The noise-reduced voltage and current signals are then converted to digital signals using an analog-to-digital conversion module. Finally, temperature compensation is applied to the digital voltage and current signals using a temperature compensation module, improving the accuracy of determining the voltage and current signals from the three-phase energy meter.

[0061] 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, the module performs phase modulation through an FPGA chip to generate a three-phase standard voltage signal and a three-phase standard current signal that meet national standards.

[0062] The working principle and beneficial effects of the above technical solution are as follows: 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 realize phase control, waveform generation, and digital-to-analog conversion. The FPGA (Field-Programmable Gate Array) is responsible for real-time phase control and power grid operating condition simulation, including static phase calibration, dynamic operating condition simulation, and synchronization control. Built-in voltage and current transformers handle 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, significantly improving signal accuracy and stability. This facilitates the accurate generation of three-phase standard voltage and current signals that meet national standards, establishing a reliable reference standard and improving the accuracy of error calculation.

[0063] According to some embodiments of the present invention, an error analysis processing module includes:

[0064] The first calculation module is used to perform spectrum analysis on the voltage and current signals of the three-phase energy meter based on the fast Fourier transform, separate the fundamental component and harmonic components, and calculate the additional error caused by the harmonic components.

[0065] The comparison module is used to establish the actual amplitude-phase model of the voltage and current signals of the three-phase energy meter based on the least squares method; to establish the standard amplitude-phase model of the three-phase standard voltage signal and the three-phase standard current signal based on the least squares method; to establish the correspondence between the actual amplitude-phase model and the standard amplitude-phase model; and to perform point-to-point comparison based on the correspondence to obtain the basic error.

[0066] The second calculation module is used to calculate the sum of the additional error and the basic error, and the sum is used as the comprehensive error of the three-phase energy meter.

[0067] The working principle and beneficial effects of the above technical solution are as follows: Based on Fast Fourier Transform (FFT), the voltage and current signals of the three-phase energy meter are analyzed to separate the fundamental and harmonic components, and the additional error caused by the harmonic components is calculated. Based on the least squares method, an actual amplitude-phase model of the voltage and current signals of the three-phase energy meter is established. Based on the least squares method, the voltage amplitude and phase, current amplitude and phase of the corresponding actual amplitude-phase model are determined. Based on the least squares method, a standard amplitude-phase model of the three-phase standard voltage and current signals is established. Based on the least squares method, the standard voltage amplitude and phase, standard current amplitude and phase of the corresponding standard amplitude-phase model are determined. When calculating the basic error, the influence of 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 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 energy meter, which improves the accuracy of obtaining the comprehensive error.

[0068] According to some embodiments of the present invention, a first computing module includes:

[0069] The separation module is used to perform spectrum analysis on the voltage and current signals of a three-phase energy meter based on fast Fourier transform, separating the fundamental and harmonic components of each phase voltage and the fundamental and harmonic components of each phase current.

[0070] The first determining module is used to determine the fundamental power of each phase based on the fundamental components of the voltage and current of each phase, and sum the values ​​to obtain the total fundamental power; and determine the fundamental energy based on the total fundamental power and the measurement time.

[0071] The second determining module is used to determine the harmonic power of each phase based on the harmonic components of the voltage and the current of each phase, and to obtain the total active power by summing the harmonic power of each phase with the total fundamental power; and to determine the total electrical energy based on the total active power and the measurement time.

[0072] The third determining module is used to calculate the difference between the total electrical energy and the fundamental electrical energy, and the ratio of the difference to the fundamental electrical energy is determined as the additional error caused by the harmonic components.

[0073] The working principle and beneficial effects of the above technical solution are as follows: Based on the Fast Fourier Transform (FFT), the voltage and current signals of the three-phase energy meter are analyzed to separate the fundamental and harmonic components of each phase voltage and each phase current. The fundamental power of each phase is determined and summed based on the fundamental components of the voltage and current of each phase, resulting in the total fundamental power. The fundamental energy is determined based on the total fundamental power and measurement time. The harmonic power of each phase is determined based on the harmonic components of the voltage and current of each phase. The total active power is obtained by summing the harmonic power of each phase with the total fundamental power. The total energy is determined based on the total active power and measurement time. The difference between the total energy and the fundamental energy is calculated, and the ratio of this difference to the fundamental energy is determined as the additional error caused by the harmonic components. By fully considering the impact of the additional error caused by the harmonic components on the comprehensive error measurement, the accuracy of determining the additional error is improved.

[0074] According to some embodiments of the present invention, the comparison module includes:

[0075] The fourth determining module is used for:

[0076] The actual amplitude-phase model of the voltage signal and the actual amplitude-phase model of the current signal of the three-phase energy meter are established based on the least squares method.

[0077]

[0078]

[0079] in, This is the actual amplitude-phase model of the voltage signal of a three-phase energy meter; This is the actual amplitude-phase model of the current signal from a three-phase energy meter. , These represent the voltage amplitude and current amplitude of the i-th harmonic, respectively, fitted using the least squares method. , These are the voltage phase and current phase of the i-th harmonic, respectively, fitted using the least squares method. The number of harmonics; Angular frequency; It is a time variable;

[0080] The standard voltage amplitude and standard current amplitude of the i-th harmonic in the standard amplitude-phase model are determined based on the least squares method.

[0081] A module is established to establish the correspondence between the actual amplitude-phase model and the standard amplitude-phase model. Based on the correspondence, a point-to-point comparison is performed to determine the voltage amplitude error and current amplitude error of each harmonic.

[0082] The average 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.

[0083] The working principle and beneficial effects of the above technical solution are as follows: Based on the least squares method, actual amplitude-phase models of the voltage signal and current signal of a three-phase energy meter are established. Specifically, the voltage amplitude, current amplitude, voltage phase, and current phase of the i-th harmonic in the actual amplitude-phase model are determined by least squares fitting. Based on the same principle, the standard voltage amplitude and standard current amplitude of the i-th harmonic in the standard amplitude-phase model are determined. A correspondence is established between the actual amplitude-phase model and the standard amplitude-phase model. Point-to-point comparisons are performed based on this correspondence to determine the voltage amplitude error and current amplitude error for each harmonic. The voltage amplitude error is calculated by comparing the difference between the voltage amplitude of the i-th harmonic in the actual amplitude-phase model and the standard voltage amplitude, and the ratio of this difference to the standard voltage amplitude is taken as the voltage amplitude error. The current amplitude error is calculated by comparing the difference between the current amplitude of the i-th harmonic in the actual amplitude-phase model and the standard current amplitude, and the ratio of this difference to the standard current amplitude is taken as the current amplitude error. The average of the sum of the products of the voltage amplitude error and the current amplitude error for each harmonic is taken as the basic error. This facilitates accurate calculation of the basic error, thereby improving the accuracy of determining the overall error.

[0084] According to some embodiments of the present invention, it further includes: a monitoring module for monitoring the connection status and signal source output status of the snap-on signal acquisition module, automatically pausing the measurement and issuing an audible and visual alarm when poor contact or signal distortion is detected, and simultaneously recording the fault code and the time of fault occurrence.

[0085] The working principle and beneficial effects of the above technical solution are as follows: 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 fault occurrence are recorded, which facilitates the timely detection of abnormalities in the error measurement process and ensures the effective performance of the error measurement.

[0086] According to some embodiments of the present invention, it further includes: a recording module for recording the comprehensive error and timestamp information of the three-phase energy meter, and displaying the error trend curve in real time with a graphical interface.

[0087] The working principle and beneficial effects of the above technical solution are as follows: Based on the recording module, the comprehensive error and timestamp information of the three-phase energy meter are recorded, and the error trend curve is displayed in real time with a graphical interface, which facilitates the display and analysis of the comprehensive measurement error.

[0088] 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 energy meter through a pressure sensor. When the pressure value is lower than a preset threshold, it determines poor contact and issues an early warning.

[0089] The working principle and beneficial effects of the above technical solution are as follows: The monitoring module is used to monitor the contact pressure between the snap-on signal acquisition module and the three-phase energy meter through a pressure sensor. When the pressure value is lower than the preset threshold, it determines poor contact and issues an early warning, which facilitates the monitoring of the connection status between the snap-on signal acquisition module and the three-phase energy meter and ensures the effective measurement of errors.

[0090] like Figure 3 As shown, according to some embodiments of the present invention, the measurement method of the snap-on three-phase energy meter comprehensive error measuring device as described above includes steps S1-S3:

[0091] S1. Synchronously acquire the voltage and current signals of the three-phase energy meter;

[0092] S2. Generate three-phase standard voltage signals and three-phase standard current signals that meet national standards;

[0093] S3. Determine the comprehensive error of the three-phase energy meter based on the voltage signal, current signal, three-phase standard voltage signal, and three-phase standard current signal of the three-phase energy meter; the comprehensive error is the sum of the basic error and the additional error caused by harmonic components.

[0094] The beneficial effects of the above technical solution are as follows: The detachable connection between the insulated snap-fit ​​structure and the voltage and current interfaces of the three-phase energy meter greatly simplifies the connection process, eliminating the need for specialized tools and complex wiring operations, significantly shortening installation time, effectively preventing operators from coming into contact with high-voltage signals, and improving the safety of on-site measurements. By introducing the calculation of additional errors caused by harmonic components, the error of the energy meter is evaluated in a more realistic way, improving the accuracy of determining the overall error of the three-phase energy meter.

[0095] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A snap-on type three-phase energy meter comprehensive error measuring device, characterized in that, include: The snap-on signal acquisition module uses an insulated 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. The standard signal generation module is 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. Based on the voltage signal, current signal, three-phase standard voltage signal and three-phase standard current signal of the three-phase energy meter, it determines the comprehensive error of the three-phase energy meter. The comprehensive error is the sum of the basic error and the additional error caused by harmonic components. The error analysis and processing module includes: The first calculation module is used to perform spectrum analysis on the voltage and current signals of the three-phase energy meter based on the fast Fourier transform, separate the fundamental component and harmonic components, and calculate the additional error caused by the harmonic components. The comparison module is used to establish the actual amplitude-phase model of the voltage and current signals of the three-phase energy meter based on the least squares method; to establish the standard amplitude-phase model of the three-phase standard voltage signal and the three-phase standard current signal based on the least squares method; to establish the correspondence between the actual amplitude-phase model and the standard amplitude-phase model; and to perform point-to-point comparison based on the correspondence to obtain the basic error. The second calculation module is used to calculate the sum of the additional error and the basic error, and the sum is used as the comprehensive error of the three-phase energy meter. The first calculation module includes: The separation module is used to perform spectrum analysis on the voltage and current signals of a three-phase energy meter based on fast Fourier transform, separating the fundamental and harmonic components of each phase voltage and the fundamental and harmonic components of each phase current. The first determining module is used to determine the fundamental power of each phase based on the fundamental components of the voltage and current of each phase, and sum the values ​​to obtain the total fundamental power; and determine the fundamental energy based on the total fundamental power and the measurement time. The second determining module is used to determine the harmonic power of each phase based on the harmonic components of the voltage and the current of each phase, and to obtain the total active power by summing the harmonic power of each phase with the total fundamental power; and to determine the total electrical energy based on the total active power and the measurement time. The third determining module is used to calculate the difference between the total electrical energy and the fundamental electrical energy, and the ratio of the difference to the fundamental electrical energy is determined as the additional error caused by the harmonic components; The comparison module includes: The fourth determining module is used for: The actual amplitude-phase model of the voltage signal and the actual amplitude-phase model of the current signal of the three-phase energy meter are established based on the least squares method. in, This is the actual amplitude-phase model of the voltage signal of a three-phase energy meter; This is the actual amplitude-phase model of the current signal from a three-phase energy meter. , These represent the voltage amplitude and current amplitude of the i-th harmonic, respectively, fitted using the least squares method. , These are the voltage phase and current phase of the i-th harmonic, respectively, fitted using the least squares method. The number of harmonics; Angular frequency; It is a time variable; The standard voltage amplitude and standard current amplitude of the i-th harmonic in the standard amplitude-phase model are determined based on the least squares method. A module is established to establish the correspondence between the actual amplitude-phase model and the standard amplitude-phase model. Based on the correspondence, a point-to-point comparison is performed to determine the voltage amplitude error and current amplitude error of each harmonic. The average 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.

2. The snap-on three-phase energy meter comprehensive error measuring device as described in 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; among which, Clip-on voltage probes are used to acquire analog voltage signals from three-phase energy meters based on differential amplifier circuits. Clip-on current probes are used to collect analog current signals from three-phase energy meters. The noise reduction module is used to perform noise reduction processing on analog voltage signals and analog current signals to obtain noise-reduced voltage signals and noise-reduced current signals. The analog-to-digital conversion module is used to perform analog-to-digital conversion on the noise-reduced voltage signal and the noise-reduced current signal to obtain the digital voltage signal and the digital current signal. The temperature compensation module is used to monitor the ambient temperature in real time through a temperature sensor, query a preset temperature-compensation coefficient data table based on the ambient temperature to obtain the compensation coefficient, and dynamically correct the digital voltage signal and digital current signal based on the compensation coefficient to obtain the voltage signal and current signal of the three-phase energy meter.

3. The snap-on three-phase energy meter comprehensive error measuring device as described in 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 uses an FPGA chip for phase control to generate three-phase standard voltage signals and three-phase standard current signals that meet national standards.

4. The snap-on three-phase energy meter comprehensive error measuring device as described in claim 1, characterized in that, Also includes: The monitoring module is used to monitor the connection status and signal source output status of the snap-on signal acquisition module. 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 the fault occurrence are recorded.

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

6. The snap-on three-phase energy meter comprehensive error measuring device as described in claim 4, characterized in that, The monitoring module is used to monitor the contact pressure between the snap-on signal acquisition module and the three-phase energy meter through a pressure sensor. When the pressure value is lower than the preset threshold, it determines poor contact and issues an early warning.

7. The measurement method of the snap-on three-phase energy meter comprehensive error measuring device as described in any one of claims 1-6, characterized in that, include: Simultaneously acquire voltage and current signals from three-phase energy meters; Generate three-phase standard voltage signals and three-phase standard current signals that meet national standards; The comprehensive error of the three-phase 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 energy meter; the comprehensive error is the sum of the basic error and the additional error caused by harmonic components.

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