A multi-loop sampling metrology system and method

Abstract

This invention discloses a multi-loop sampling metering system and method, relating to the field of power metering technology. It includes: a transformer output-side metering module for real-time acquisition of total output voltage, current, power, and energy data; a multi-user-end voltage sampling and status detection module for time-sharing acquisition of voltage data from each user end, and simultaneously determining the connection status of the user-end voltage loop based on the voltage sampling values; and a main control and data processing module for controlling the system's operation, receiving and processing data acquired by the transformer output-side metering module and the multi-user-end voltage sampling and status detection module. By performing linked verification of the transformer output-side and user-end metering data, the accuracy of the metering data is ensured, facilitating rapid location of abnormal loops.

Description

Technical Field

[0001] This invention relates to the field of power metering technology, specifically to a multi-loop sampling metering system and method. Background Technology

[0002] In existing multi-user energy metering schemes, single-chip multi-loop sampling has a limited number of channels. If a single metering chip is used, the maximum number of sampling channels is 7, namely 4 current sampling channels and 3 voltage sampling channels. If it is necessary to add voltage sampling at the user end, there are no extra voltage sampling channels unless multiplexing is done through an analog switch. This affects the metering accuracy of the actual transformer output side, because after switching through the analog switch, the voltage sampling path originally connected to the transformer output side is connected to the user end, and thus the metering loop voltage cannot be obtained in real time. In other words, the metering data of the transformer output side and the user end are not linked for verification, which easily leads to metering deviations and makes it difficult to quickly locate abnormal loops. Summary of the Invention

[0003] This invention provides a multi-loop sampling metering system and method, which verifies the metering data between the transformer output side and the user end in a linked manner to ensure the accuracy of the metering data and facilitate the rapid location of abnormal loops.

[0004] This invention provides the following technical solution: a multi-loop sampling and metering system, comprising:

[0005] The transformer output side metering module is used to collect total output voltage, current, power and energy data in real time;

[0006] The multi-user terminal voltage sampling and status detection module is used to collect voltage data from each user terminal in a time-division manner, and at the same time determine the connection status of the user terminal voltage loop based on the voltage sampling value.

[0007] The main control and data processing module, along with the transformer output side metering module and the multi-user terminal voltage sampling and status detection module, is used to control the operation of the system and to receive and process the data collected by the transformer output side metering module and the multi-user terminal voltage sampling and status detection module.

[0008] As a further improvement of the present invention, the transformer output side metering module includes a three-phase metering chip A. The three-phase voltage sampling channel of the three-phase metering chip A is connected to the transformer output side through a voltage transformer or a resistor divider network, and the current sampling channel of the three-phase metering chip A is connected to the transformer output side through a current transformer or a shunt.

[0009] As a further improvement of the present invention, the multi-user terminal voltage sampling and status detection module includes a three-phase metering chip B. The three-phase voltage of each user terminal is respectively connected to the input terminal of a set of analog switches. The three-phase voltage sampling channel of the three-phase metering chip B is connected to the output terminal of the analog switches. The selection control terminal of the analog switches is connected to the I / O port of the MCU. The MCU sends a switching command to realize the sequential cyclic sampling of the voltage of different user terminals.

[0010] As a further improvement of the present invention, the main control and data processing module includes an MCU; the MCU is connected to the three-phase metering chip A and the three-phase metering chip B via an SPI / I2C bus.

[0011] A multi-loop sampling metering method, applicable to the aforementioned multi-loop sampling metering system, includes the following steps:

[0012] Three-phase metering chip A collects three-phase voltage and current data from the transformer output side, calculates total active power, total reactive power and total electrical energy, and uploads the data to the MCU;

[0013] The MCU sends selection signals in a preset order to control the analog switches to switch to the voltage sampling circuit of the first to Nth user terminals in sequence. The three-phase metering chip B collects the phase voltage of each user terminal and feeds the sampled data back to the MCU.

[0014] The MCU determines the status of the user-end voltage circuit based on the voltage sampling data of the three-phase metering chip B. The determination result is stored by the MCU and uploaded to the background management system through the communication interface.

[0015] The MCU aggregates the power data from all users, calculates the total power consumption of each user, and performs a difference check with the total power consumption collected by the three-phase metering chip A. When the difference exceeds the threshold, a metering anomaly alarm is triggered.

[0016] As a further improvement of the present invention, the MCU executes the following determination logic based on the sampling data of the three-phase metering chip B:

[0017] If the sampled value of a phase voltage at the user end is within ±20% of the corresponding phase voltage of the transformer, the voltage circuit connection of that phase is considered normal.

[0018] If the voltage sampling value of a certain phase at the user end is less than 10% of the rated voltage and the duration exceeds the preset threshold, it is determined that the voltage circuit of that phase is open or not connected to power.

[0019] If the fluctuation range of a certain phase voltage sampling value at the user end is greater than 15%, it is determined that there is a loose connection fault in the voltage circuit of that phase.

[0020] As a further improvement of the present invention, in the step of MCU controlling the analog switch to switch sequentially, a synchronous sampling frequency generation technology based on phase-locked loop is adopted, specifically including: acquiring the voltage signal on the output side of the transformer as the fundamental signal; performing phase-locked frequency multiplication on the fundamental signal to generate a sampling frequency signal that is strictly synchronized with the grid frequency; and using the sampling frequency signal to precisely control the switching sequence of the multi-channel switching switch and the sampling start time of the three-phase metering chip B, so that the cyclic sampling of different user-end voltages is performed at the same phase point of the grid waveform.

[0021] As a further improvement of the present invention, before the MCU summarizes the power data of all user terminals and performs differential verification with the total power, it also includes a phase angle error correction step: the MCU calculates the fixed phase angle error introduced by time-division switching sampling according to the sampling time relationship of each user terminal voltage; and performs phase angle error correction on the voltage sampling data of each user terminal collected by the three-phase metering chip B based on the fast Fourier transform algorithm, so as to eliminate the impact of asynchronous sampling on harmonic analysis, power calculation and subsequent differential verification accuracy.

[0022] As a further improvement of the present invention, the MCU performs the following power quality analysis steps based on the corrected voltage and current data of each user terminal:

[0023] Based on the Fast Fourier Transform algorithm, the harmonic content and total harmonic distortion rate of voltage and current at each user terminal are calculated.

[0024] Real-time monitoring and recording of events where the power factor of each user terminal circuit falls below a preset threshold.

[0025] As a further improvement of the present invention, the MCU is externally connected to a storage unit, and the data collected by the three-phase metering chip A and the three-phase metering chip B are stored in the storage unit.

[0026] The present invention has the following beneficial effects:

[0027] In this invention, the combination of dual three-phase metering chips and analog switches eliminates the need for independent metering chips for each user terminal, significantly reducing the hardware cost of multi-loop metering. While achieving multi-user energy metering, it integrates voltage connection status detection, eliminating the need for additional detection sensors and simplifying circuit design. Data linkage verification between the transformer output side and the user terminal enables rapid location of abnormal metering loops, improving the accuracy and reliability of the multi-user metering system. Furthermore, by increasing the number of channels in the analog switches, the number of user terminals can be flexibly expanded to adapt to multi-loop metering scenarios of different scales. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the arrangement of the metering system in the power grid according to the present invention.

[0029] Figure 2 for Figure 1 Internal metering function block diagram of the DCU.

[0030] Figure 3 This is a structural block diagram of the metering system in this invention.

[0031] Figure 4 This is a flowchart of the measurement method in this invention. Detailed Implementation

[0032] The technical solutions of the embodiments of this specification will be explained and described below with reference to the accompanying drawings. However, the following embodiments are only preferred embodiments of this specification and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments in the implementation methods without creative effort are all within the protection scope of this specification.

[0033] The terms "first," "second," "third," etc., in the description, claims, and accompanying drawings are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus.

[0034] In the following description, terms such as “inner,” “outer,” “upper,” “lower,” “left,” and “right” are used only to facilitate the description of the embodiments and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this specification.

[0035] All data involved in this application are information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data comply with the relevant laws, regulations and standards of the relevant countries and regions.

[0036] Example 1

[0037] Please see Figure 1-3 As shown, a multi-loop sampling metering system includes:

[0038] The transformer output side metering module is used to collect total output voltage, current, power and energy data in real time.

[0039] The transformer output side metering module includes a three-phase metering chip A. The three-phase voltage sampling channel of the three-phase metering chip A is connected to the transformer output side through a voltage transformer or a resistor divider network. The current sampling channel of the three-phase metering chip A is connected to the transformer output side through a current transformer or a shunt.

[0040] The three-phase metering chip A is model ADE7758 or ATT7022E. The three-phase voltage on the transformer output side is conditioned by a voltage transformer or a resistor divider network and then connected to the three-phase voltage sampling channel of the three-phase metering chip A. The three-phase current is converted by a current transformer or a shunt and then connected to the three-phase current sampling channel of chip A. The total output voltage, current, power and energy data on the transformer output side are collected in real time and used as a reference for multi-user metering.

[0041] The multi-user terminal voltage sampling and status detection module is used to collect voltage data from each user terminal in a time-division manner, and at the same time determine the connection status of the user terminal voltage loop based on the voltage sampling value.

[0042] The multi-user terminal voltage sampling and status detection module includes a three-phase metering chip B. The three-phase voltage of each user terminal is connected to the input terminal of a set of analog switches. The three-phase voltage sampling channel of the three-phase metering chip B is connected to the output terminal of the analog switches. The selection control terminal of the analog switches is connected to the I / O port of the MCU. The MCU sends switching commands to realize the sequential cyclic sampling of voltages from different user terminals.

[0043] The three-phase metering chip B is the same model or has the same accuracy class as the three-phase metering chip A. The multi-channel single-pole multi-throw analog switch is model CD4051 or ADG508, and the MCU can be model STM32 or MSP430. The three-phase voltage (or single-phase voltage, adapted according to user type) of each user terminal is connected to the input terminal of a set of analog switches. The output terminals of the analog switches are aggregated and connected to the three-phase voltage sampling channel of the three-phase metering chip B. The selection control terminal of the analog switch is connected to the I / O port of the main control MCU. The MCU sends switching commands to realize the sequential cyclic sampling of the voltage of different user terminals.

[0044] The main control and data processing module, along with the transformer output side metering module and the multi-user terminal voltage sampling and status detection module, is used to control the operation of the system and to receive and process the data collected by the transformer output side metering module and the multi-user terminal voltage sampling and status detection module.

[0045] The main control and data processing module includes an MCU; the MCU is connected to the three-phase metering chip A and the three-phase metering chip B via SPI / I2C bus.

[0046] The MCU has an external storage unit (such as Flash) and a communication interface (such as RS485, LoRa, Ethernet). The MCU communicates with three-phase metering chip A and three-phase metering chip B via SPI / I2C bus to read metering data and sampled values; the MCU outputs control signals to the analog switch to set the sampling switching period (such as 100ms / user).

[0047] Taking the electricity metering of 12 residential households as an example:

[0048] First, ADE7758 was selected as the three-phase metering chip A and three-phase metering chip B, and 3 CD4051 (8-channel) analog switches were selected to expand to 12 user-end voltage sampling channels.

[0049] Second, the MCU selected is STM32F103, the analog switch switching cycle is set to 100ms, the voltage sampling of one user is completed every 100ms, and the cyclic sampling cycle of 12 users is 1.2s;

[0050] Third, the voltage connection status judgment threshold is set as follows: the normal voltage range is 200~240V (single-phase 220V power grid), the open circuit judgment threshold is <22V, and the loose connection judgment threshold is voltage fluctuation >33V.

[0051] Fourth, the communication interface is RS485, which uploads the total metering data, sub-user data and connection status information to the concentrator.

[0052] The aforementioned multi-loop sampling metering system, through the combination of dual three-phase metering chips and analog switches, eliminates the need for an independent metering chip for each user terminal, significantly reducing the hardware cost of multi-loop metering. While achieving multi-user energy metering, it integrates voltage connection status detection functionality, eliminating the need for additional detection sensors and simplifying circuit design. The data linkage verification between the transformer output side and the user terminal enables rapid location of metering abnormal loops, improving the accuracy and reliability of the multi-user metering system. By increasing the number of channels in the analog switches, the number of user terminals can be flexibly expanded to adapt to multi-loop metering scenarios of different scales (such as power distribution in residential communities and office buildings).

[0053] Figure 1 and Figure 2 In Chinese, DCU stands for Data collector unit.

[0054] In this application, MCU refers to Microcontroller Unit, also known as Single Chip Microcomputer or Microcontroller.

[0055] Example 2

[0056] Please see Figure 4 As shown, a multi-loop sampling metering method, applicable to the aforementioned multi-loop sampling metering system, includes the following steps:

[0057] S1. The three-phase metering chip A collects the three-phase voltage and current data on the output side of the transformer, calculates the total active power, total reactive power and total electrical energy, and uploads the data to the MCU.

[0058] In S1, the three-phase metering chip A continuously collects the three-phase voltages U(A total), U(B total), U(C total) and three-phase currents I(A total), I(B total), I(C total) from the transformer output side, calculates the total active power P(total), total reactive power Q(total) and total electrical energy E(total) in real time, and uploads the data to the MCU.

[0059] S2. The MCU sends selection signals in a preset order to control the analog switches to switch to the voltage sampling circuit of the 1st to Nth user terminals in sequence. The three-phase metering chip B collects the phase voltage of each user terminal and feeds the sampled data back to the MCU.

[0060] In S2, the three-phase metering chip B samples the phase voltage of the currently selected user, obtaining the user-end voltage values ​​U(User A n), U(User B n), and U(User C n) (n=1,2,...,N), and feeds the sampled data back to the MCU. The sampling switching cycle needs to be set according to the metering accuracy requirements to ensure that the sampling frequency of each user end meets the power metering standard (e.g., ≥10Hz).

[0061] S3. The MCU determines the status of the user-end voltage circuit based on the voltage sampling data of the three-phase metering chip B. The determination result is stored by the MCU and uploaded to the background management system through the communication interface.

[0062] In S3, the MCU executes the following decision logic based on the sampled data from the three-phase metering chip B:

[0063] Normal connection determination: If the voltage sampling value U (phase user n) of a certain phase at the user end is within ±20% of the corresponding phase voltage of the transformer (the threshold can be adjusted according to the actual power grid fluctuations), the voltage circuit connection of that phase is determined to be normal.

[0064] Circuit break determination: If the voltage sampling value U (phase user n) of a certain phase at the user end is less than 10% of the rated voltage and the duration exceeds the preset threshold (e.g., 500ms), the voltage circuit of that phase is determined to be open or disconnected.

[0065] Loose connection determination: If the fluctuation range of the voltage sampling value of a certain phase at the user end is greater than 15% (relative to the stable value), it is determined that there is a loose connection fault in the voltage circuit of that phase.

[0066] S4. The MCU summarizes the power data of all users, calculates the total power of each user, and performs a difference verification with the total power collected by the three-phase metering chip A. When the difference exceeds the threshold, a metering abnormality alarm is triggered.

[0067] In S4, the MCU aggregates the power data from all user terminals (combined with user terminal current sampling, which can be externally connected to a CT or extended by the three-phase metering chip B), calculates the total power E (total for each user), and performs a difference check with the E (total) collected by the three-phase metering chip A. When the difference exceeds ±2% (configurable), a metering abnormality alarm is triggered.

[0068] In the above scheme, the user-end voltage is sampled in a time-division cyclic manner using analog switches. This results in time differences in the data of each loop, and the sampling points of each loop are randomly distributed on different phases of the power grid waveform period. The resulting systematic phase error is random and unpredictable, making it difficult to effectively correct through subsequent algorithms. This is especially problematic when performing harmonic power calculations and vector analysis, where it introduces non-negligible errors. Therefore, in the step of MCU controlling the sequential switching of analog switches, a synchronous sampling frequency generation technology based on phase-locked loops is adopted. Specifically, this includes: acquiring the voltage signal from the transformer output side as the fundamental signal; performing phase-locked frequency multiplication on the fundamental signal to generate a sampling frequency signal that is strictly synchronized with the power grid frequency; and using the sampling frequency signal to precisely control the switching sequence of the multi-channel switching switches and the sampling start time of the three-phase metering chip B, so that the cyclic sampling of different user-end voltages is performed at the same phase points of the power grid waveform.

[0069] By employing techniques such as phase-locked loop (PLL) frequency multiplication, the sampling time is synchronized with the power grid cycle, ensuring that cyclic sampling at different user terminals occurs at equiphase points on the power grid waveform. This means that although the sampling of different loops occurs sequentially, their phase relationship relative to the fundamental wave of the power grid is fixed and known. For example, the sampling point of loop b always lags behind loop a by a fixed electrical angle. This fixed phase difference can be accurately eliminated during data processing using subsequent phase angle error correction algorithms. This is a prerequisite for achieving high-precision multi-loop harmonic analysis and power calculation. Moreover, this method does not degrade amplitude measurement performance, which is crucial for calculating power quality parameters such as harmonic content and total harmonic distortion (THD), significantly improving the accuracy of harmonic measurement and power quality analysis.

[0070] Before aggregating the power data from all user terminals and performing differential verification with the total power, the MCU also includes a phase angle error correction step: the MCU calculates the fixed phase angle error introduced by time-division switching sampling based on the sampling time relationship of each user terminal voltage; and performs phase angle error correction on the voltage sampling data of each user terminal collected by the three-phase metering chip B based on the fast Fourier transform algorithm, so as to eliminate the impact of asynchronous sampling on harmonic analysis, power calculation and subsequent differential verification accuracy.

[0071] Based on the corrected voltage and current data of each user terminal, the MCU performs the following power quality analysis steps:

[0072] 1. Based on the Fast Fourier Transform algorithm, calculate the harmonic content and total harmonic distortion rate of voltage and current at each user terminal;

[0073] 2. Monitor and record in real time any over-limit events where the power factor of each user terminal circuit is lower than the preset threshold.

[0074] The MCU is externally connected to a storage unit, and the data collected by the three-phase metering chip A and the three-phase metering chip B are stored in the storage unit.

[0075] The embodiments described above are merely preferred embodiments of this specification and are not intended to limit the scope of this specification. Any modifications and improvements made by those skilled in the art to the technical solutions of this specification without departing from the spirit of this specification should fall within the protection scope defined by the claims of this specification.

Claims

1. A multi-loop sampling metrology system, characterized by, include: The transformer output side metering module is used to collect total output voltage, current, power and energy data in real time; The multi-user terminal voltage sampling and status detection module is used to collect voltage data from each user terminal in a time-division manner, and at the same time determine the connection status of the user terminal voltage loop based on the voltage sampling value. The main control and data processing module, along with the transformer output side metering module and the multi-user terminal voltage sampling and status detection module, is used to control the operation of the system and to receive and process the data collected by the transformer output side metering module and the multi-user terminal voltage sampling and status detection module.

2. The multi-channel sampling metrology system of claim 1, wherein, The transformer output side metering module includes a three-phase metering chip A. The three-phase voltage sampling channel of the three-phase metering chip A is connected to the transformer output side through a voltage transformer or a resistor divider network. The current sampling channel of the three-phase metering chip A is connected to the transformer output side through a current transformer or a shunt.

3. The multi-channel sampling metrology system of claim 2, wherein, The multi-user terminal voltage sampling and status detection module includes a three-phase metering chip B. The three-phase voltage of each user terminal is connected to the input terminal of a set of analog switches. The three-phase voltage sampling channel of the three-phase metering chip B is connected to the output terminal of the analog switches. The selection control terminal of the analog switches is connected to the I / O port of the MCU. The MCU sends switching commands to realize the sequential cyclic sampling of voltages from different user terminals.

4. The multi-channel sampling metrology system of claim 3, wherein, The main control and data processing module includes an MCU; the MCU is connected to the three-phase metering chip A and the three-phase metering chip B via SPI / I2C bus.

5. A multi-loop sampling metrology method, the method being applicable to the multi-loop sampling metrology system of claim 4, characterized by, Includes the following steps: Three-phase metering chip A collects three-phase voltage and current data from the transformer output side, calculates total active power, total reactive power and total electrical energy, and uploads the data to the MCU; The MCU sends selection signals in a preset order to control the analog switches to switch to the voltage sampling circuit of the first to Nth user terminals in sequence. The three-phase metering chip B collects the phase voltage of each user terminal and feeds the sampled data back to the MCU. The MCU determines the status of the user-end voltage circuit based on the voltage sampling data of the three-phase metering chip B. The determination result is stored by the MCU and uploaded to the background management system through the communication interface. The MCU aggregates the power data from all users, calculates the total power consumption of each user, and performs a difference check with the total power consumption collected by the three-phase metering chip A. When the difference exceeds the threshold, a metering anomaly alarm is triggered.

6. The multi-channel sampling metrology method of claim 5, wherein, Based on the sampled data from the three-phase metering chip B, the MCU executes the following decision logic: If the sampled value of a phase voltage at the user end is within ±20% of the corresponding phase voltage of the transformer, the voltage circuit connection of that phase is considered normal. If the voltage sampling value of a certain phase at the user end is less than 10% of the rated voltage and the duration exceeds the preset threshold, it is determined that the voltage circuit of that phase is open or not connected to power. If the fluctuation range of a certain phase voltage sampling value at the user end is greater than 15%, it is determined that there is a loose connection fault in the voltage circuit of that phase.

7. The multi-channel sampling metrology method of claim 5, wherein, In the step of MCU controlling the sequential switching of analog switches, a synchronous sampling frequency generation technology based on phase-locked loop is adopted, which specifically includes: acquiring the voltage signal on the transformer output side as the fundamental signal; performing phase-locked frequency multiplication on the fundamental signal to generate a sampling frequency signal that is strictly synchronized with the grid frequency; and using the sampling frequency signal to precisely control the switching sequence of the multi-channel switching switch and the sampling start time of the three-phase metering chip B, so that the cyclic sampling of different user-end voltages is performed at the same phase point of the grid waveform.

8. The multi-channel sampling metrology method of claim 7, wherein, Before aggregating the power data from all user terminals and performing differential verification with the total power, the MCU also includes a phase angle error correction step: the MCU calculates the fixed phase angle error introduced by time-division switching sampling based on the sampling time relationship of each user terminal voltage; and performs phase angle error correction on the voltage sampling data of each user terminal collected by the three-phase metering chip B based on the fast Fourier transform algorithm, so as to eliminate the impact of asynchronous sampling on harmonic analysis, power calculation and subsequent differential verification accuracy.

9. The multi-loop sampling and measurement method according to claim 5 or 8, characterized in that, Based on the corrected voltage and current data of each user terminal, the MCU performs the following power quality analysis steps: Based on the Fast Fourier Transform algorithm, the harmonic content and total harmonic distortion rate of voltage and current at each user terminal are calculated. Real-time monitoring and recording of events where the power factor of each user terminal circuit falls below a preset threshold.

10. The multi-loop sampling and measurement method according to claim 5, characterized in that, The MCU is externally connected to a storage unit, and the data collected by the three-phase metering chip A and the three-phase metering chip B are stored in the storage unit.

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