An ac power remote self-calibration method and system

Abstract

This invention discloses a remote self-calibration method and system for AC power, relating to the field of power metering and calibration technology. The method includes: establishing a calibration time base via satellite common-view to remotely trace the values ​​of the field reference signal; calculating the channel relative error and correction coefficient by injecting reference voltage and current signals into the sampling channel to complete dual-channel voltage and current calibration; synchronizing voltage and current sampling data using absolute time stamps to independently calculate power values ​​at both the field and laboratory ends; and automatically generating a power gain correction coefficient by comparing the results and feeding it back to the field end for compensation updates. The system includes a field calibration end and a laboratory standard end, enabling data interaction through bidirectional communication. This invention achieves remote, high-precision, and fully automatic self-calibration of power metering devices, solving the problems of low efficiency and long cycle in traditional field calibration, and is suitable for smart grid and distributed energy metering scenarios.

Description

Technical Field

[0001] This invention relates to the field of electrical energy metering and calibration technology, and in particular to a remote self-calibration method and system for AC power. Background Technology

[0002] AC power metering is a core technological foundation for smart grid operation, electricity trade settlement, and electric vehicle charging facility operation. Its metering accuracy directly affects fair electricity trading and the level of precision in energy management. With the construction of new power systems, the online and accurate operation and maintenance of massive distributed metering devices has become an urgent industry need.

[0003] Existing AC power metering devices typically employ an "analog sampling-digital processing" architecture. This involves converting the primary-side signal into a low-voltage analog quantity using voltage and current transformers and conditioning circuits. This analog-to-digital converter (ADC) then digitizes the signal, and a metering chip or DSP performs power calculations and energy accumulation. Under this approach, metering errors primarily stem from parameter drift in the sampling elements, ADC conversion nonlinearity, and the finite word length effect during digital computation. To ensure accuracy, current calibration systems heavily rely on on-site comparison and verification using standard sources or standard energy meters, or on sending the device to be calibrated to a laboratory.

[0004] However, the aforementioned existing technologies have drawbacks: Traditional on-site calibration requires the standard equipment and the equipment being calibrated to be physically located at the same site. For widely distributed charging piles and smart meters, this presents problems such as difficulties in transporting standard sources, low efficiency of manual verification, long calibration cycles, and significant interference from the on-site environment, making it difficult to support the online remote calibration needs of large-scale equipment.

[0005] Although remote time and frequency transfer technologies such as satellite common-view have been gradually applied, existing remote solutions are mostly limited to tracing at the reference signal level and fail to effectively cover the end-to-end errors within the metering device. Specifically, on the one hand, gain deviations and conversion errors caused by factors such as device aging and temperature drift in the field sampling channel cannot be directly eliminated by a remote time and frequency reference, resulting in distortion of the digital sampling data itself; on the other hand, even if the sampling data is accurate, numerical truncation and integral accumulation algorithms in the subsequent power calculation process will still introduce additional errors.

[0006] Due to the lack of a remote collaborative correction mechanism for both the sampling channel and the power calculation process, the actual calibration accuracy of existing remote metering technologies is limited, and they cannot meet the remote self-calibration requirements of high-accuracy AC power metering devices. Summary of the Invention

[0007] The purpose of this invention is to provide a remote self-calibration method and system for AC power, which aims to solve or improve at least one of the above-mentioned technical problems.

[0008] To achieve the above objectives, the present invention provides the following solution: A remote self-calibration method for AC power includes: Step S1: The field end and the laboratory end receive the time and frequency signal broadcast by the same satellite within the same observation window, measure the time difference between their respective local clocks and the satellite clock and exchange data, calculate the time deviation and average relative frequency deviation at both ends; compensate the local clock at the field end based on the time deviation and average relative frequency deviation, generate a calibration time base signal, and generate an absolute time tag for subsequent sampling data based on the calibration time base signal. Step S2: The field end converts the reference voltage into a frequency signal using the voltage-to-frequency conversion module, and performs frequency measurement using the calibration time base signal as a gate; the laboratory end performs synchronous measurement on the standard voltage; the voltage deviation is calculated based on the measurement results from both ends, and if the voltage deviation is within the preset threshold, the reference voltage is verified to be qualified. Step S3: Inject qualified reference voltage and reference current into the voltage sampling channel and current sampling channel at the field end, respectively, obtain the sampled values ​​and calculate the channel relative error; calculate the corrected conversion coefficient based on the channel relative error; Step S4: The field end synchronously samples the AC voltage and current under test, performs point-by-point calibration using the corrected conversion coefficient, obtains calibration voltage sampling data and calibration current sampling data, and adds an absolute time tag; the synchronous data stream after adding the tag is divided into two paths, one path is sent to the field end, and the other path is sent to the laboratory end. Step S5: The field terminal calculates the instantaneous power based on the received synchronous data stream, and performs cumulative integration within the metering time interval specified by the absolute time tag to obtain the field power metering value. Step S6: The laboratory receives the synchronous data stream, verifies the absolute time tag to extract data consistent with the metering time interval, establishes an independent reference energy analysis link, uses high-precision floating-point arithmetic to calculate the instantaneous power sequence, and performs numerical integration calculation to obtain the reference energy value. Step S7: The laboratory compares the on-site power metering value with the reference power value and calculates the relative error of power metering. Step S8: When the relative error of electricity metering exceeds the preset allowable error limit, the laboratory calculates the electricity metering gain correction coefficient and sends it to the field. The field uses the gain correction coefficient to compensate and update the subsequent metering results.

[0009] Furthermore, in step S1, generating the calibration time base signal includes: A moving average filter is applied to the continuously acquired time deviation sequence to obtain a smoothed time deviation estimate; The control parameters of the local oscillator at the field end are adjusted in real time using the average relative frequency deviation, so that the local clock frequency is close to the laboratory clock frequency. The adjusted local clock output is used as the calibration time base signal.

[0010] Furthermore, in step S2, the voltage deviation is calculated. The expression is: In the formula, The voltage deviation between the reference voltage and the standard voltage; , These are the number of pulses counted within 1 second at the field end and the laboratory end, respectively. , These are the calibration conversion coefficients for the field-side and laboratory-side voltage-to-frequency conversion modules, respectively. , , respectively, are the differences between adjacent time intervals within the i-th second for the field end and the laboratory end.

[0011] Furthermore, in step S3, the corrected conversion coefficient is calculated based on the channel relative error, and the expression is: In the formula, and These are the conversion coefficients for the corrected voltage and current paths, respectively; and These are the first-order linear compensation factors for the voltage channel and the current channel, respectively; and These are the voltage relative error and the current relative error, respectively.

[0012] Furthermore, in step S6, a numerical integration calculation is performed to obtain the reference electrical energy value, including: The reference electrical energy value was calculated using the composite Simpson numerical integration method. The expression is: In the formula, This is the reference electrical energy value for the laboratory. This represents the total number of sampling points within the interval. The sampling interval; This is a laboratory instantaneous power sequence; For long-term accumulation, the Kahan summation algorithm is used for error compensation accumulation.

[0013] Furthermore, in step S8, the power metering gain correction coefficient is calculated. The expression is: In the formula, This is the gain correction factor; For reference electrical energy value; This is the on-site electricity metering value.

[0014] Furthermore, it also includes step S9, in the next adjacent measurement interval after the parameter update, repeating steps S4 to S7 to obtain the corrected field value and the new reference value, and calculating the verification error; If the verification error is still greater than the preset allowable error limit, then repeat step S8 to update the parameters; If the verification error still does not meet the requirements after the number of iterations exceeds the maximum iteration threshold, the field equipment is judged to be abnormal and abnormal status information is output.

[0015] A system applying the above method includes: a field end and a laboratory end; The field terminal includes: Satellite signal receiver, used to receive time and frequency signals broadcast by satellite; Reference signal source, used to output reference voltage and reference current; The voltage-to-frequency conversion module has its input terminal connected to the voltage output terminal of the reference signal source, and is used to convert the reference voltage into a frequency signal. The counter module, whose input is connected to the output of the voltage-to-frequency conversion module and the satellite signal receiver, is used to use the calibration time base signal as the gate measurement frequency signal; The sampling circuit and analog-to-digital conversion module are used to synchronously sample and convert the injected reference voltage, reference current, and measured AC voltage and current. The power metering module, connected to the analog-to-digital conversion module, is used to calculate the on-site power metering value based on the calibrated sampling data. The laboratory side includes: A standard signal source, a voltage-to-frequency conversion module, and a frequency counting module are used to generate and measure the frequency signal corresponding to a standard voltage. The reference energy analysis and calculation module is used to receive synchronous sampling data sent by the field calibration terminal and perform high-precision numerical integration to calculate the reference energy value. The electrical energy value comparison and correction parameter generation module is connected to the reference electrical energy analysis and calculation module and the remote communication module, respectively, and is used to compare electrical energy metering values ​​and generate gain correction coefficients. Both the field end and the laboratory end include a remote communication module, which enables bidirectional transmission of time deviation data, frequency measurement data, synchronous sampling data, and gain correction coefficients.

[0016] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: This invention discloses a remote self-calibration method and system for AC power. The invention establishes a high-precision calibration time base using satellite common-view technology, achieving remote time and frequency synchronization between the field and laboratory ends, enabling power metering traceability without on-site personnel. A voltage-to-frequency conversion and absolute time stamp mechanism ensure the timing consistency of sampled data during transmission. The laboratory independently analyzes the reference power and compares it with the field value, automatically calculating correction parameters and updating them, forming a closed-loop self-calibration. This method effectively eliminates the finite word length effect and channel error, significantly improving the accuracy and efficiency of remote calibration, reducing maintenance costs, and ensuring long-term accurate and reliable power metering. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the data flow structure in the method of the present invention; Figure 2 This is a schematic diagram illustrating the workflow of the method in this embodiment; Figure 3 This is a schematic diagram of the voltage and current sampling channel calibration structure in this embodiment; Figure 4 This is a schematic diagram of the electrical energy analysis and calibration process in this embodiment. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The purpose of this invention is to provide a remote self-calibration method and system for AC power, which aims to solve or improve at least one of the above-mentioned technical problems.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 and Figure 2 As shown, the present invention provides a method for remote self-calibration of AC power, comprising: Step S1: Establish a remote time-frequency connection between the field and laboratory. The satellite signal receivers at the field end and the laboratory end continuously receive the 1PPS pulse signal broadcast by the same GPS satellite within the same preset observation window (e.g., 10 minutes).

[0023] Both the field station and the laboratory station use their respective time interval counters to measure the time difference between the local atomic clock second pulse and the GPS second pulse, denoted as […]. and .

[0024] The field and laboratory ends exchange time difference data through a remote communication module.

[0025] Based on the common-view principle, the time deviation between the local clocks at the field end and the laboratory end is calculated. The expression is: In the formula, This represents the time deviation between the field station and the laboratory station; a positive value indicates that the field clock is ahead. The time difference between the local clock and the GPS clock at the site; This represents the time difference between the local clock and the GPS clock at the laboratory.

[0026] Based on multiple sets of time deviations The average relative frequency deviation of the observed values ​​is calculated using the following expression: In the formula, The average relative frequency deviation between the field-end atomic clock and the laboratory-end atomic clock; The average time interval; and The first Second and the The time deviation in seconds.

[0027] Raw common-view data contains noise and needs to be processed before it can be used as a metrological reference. The steps for generating the calibration time base are as follows: (1) Time deviation of continuous acquisition The sequence is subjected to moving average filtering to remove high-frequency jitter components, resulting in a smoothed time bias estimate. ; (2) Calculate the average relative frequency deviation using equation (2). The control voltage of the local oscillator is adjusted in real time to make the local clock frequency approach the laboratory clock frequency. (3) The adjusted local clock output is used as the calibration time base signal. The calibration time base signal is synchronized with the laboratory time base at the physical or logical level, and its synchronization uncertainty is better than 100 ns.

[0028] After the time base calibration is completed, the satellite common-view synchronization clock at the field end enters a timekeeping state. Based on the calibration time base, it generates an absolute time tag for each subsequent set of voltage and current synchronization sampling data. The absolute time tag has an accuracy of microseconds and identifies the start and end times of the sampling window. The generated absolute time tag is embedded in the header of the sampling data packet.

[0029] Step S2: Perform remote measurement and value traceability of the field reference signal. The voltage quantity is converted into a frequency quantity using a V / F converter, and remote measurement is performed using the calibration time base constructed in step S1, including: The field-side reference signal source outputs a stable reference voltage. The input is sent to the voltage-to-frequency conversion module.

[0030] The voltage-to-frequency conversion module converts the reference voltage Converted into a field frequency signal proportional to the voltage amplitude. The output is sent to the counter module.

[0031] The counter module uses the calibration time base as a gate to measure the field frequency signal. The frequency value.

[0032] Meanwhile, the standard signal source at the laboratory end outputs a standard voltage. The signal is converted to the experimental frequency signal via a voltage-to-frequency conversion module of the same model. And using the laboratory time base as a gate, the experimental frequency signal was measured. The frequency value.

[0033] The field and laboratory ends exchange measured frequency values ​​via a remote communication module, based on the voltage-to-frequency conversion characteristics. Calculate the reference voltage at the site. Relative to standard voltage voltage deviation The expression is: In the formula, Reference voltage With standard voltage Voltage deviation; , These are the number of pulses counted within 1 second at the field end and the laboratory end, respectively. , These are the calibration conversion coefficients for the field-side and laboratory-side voltage-to-frequency conversion modules, respectively. , These are the differences between adjacent time intervals within the i-th second at the field end and the laboratory end, respectively, used to correct the non-integer cycle truncation error at the second pulse boundary.

[0034] If voltage deviation If the value exceeds the preset threshold by ±0.01%, the on-site reference source is deemed abnormal, the calibration process is terminated, and an alarm is issued. Otherwise, the reference voltage is checked. Verification passed.

[0035] like Figure 3 As shown, step S3 involves remotely calibrating the on-site voltage and current sampling channels. Reference voltage and reference current The voltage and current sampling channels at the field end are injected respectively.

[0036] Reference voltage and reference current After passing through a current transformer, conditioning circuit, and analog-to-digital converter (ADC), the sampled voltage is obtained. and sampling current Treating the sampling circuit and analog-to-digital converter (ADC) as a linear system, the sampling voltage... and sampling current The expression is: , In the formula, and These are the current conversion coefficients for the voltage channel and the current channel, respectively.

[0037] The sampled value is compared with the reference value to calculate the channel relative error, expressed as: In the formula, and These are the voltage relative error and the current relative error, respectively. and This refers to the raw digital code value output by the analog-to-digital converter (ADC). and These are the current conversion coefficients for the voltage channel and the current channel, respectively. This is the true value of the reference voltage.

[0038] Based on voltage relative error and relative error of current The sampling channel conversion coefficients are corrected to calculate new calibration coefficients, expressed as follows: In the formula, and These are the conversion coefficients for the corrected voltage and current paths, respectively; and These are the first-order linear compensation factors for the voltage channel and the current channel, respectively.

[0039] Will and Write the calibration parameter register at the field end.

[0040] Step S4: Acquire synchronous voltage and current sampling data. The field terminal synchronously samples the measured AC voltage and current, and the analog-to-digital converter (ADC) outputs the raw sequence. , Point-by-point calibration is performed using the corrected conversion coefficients, expressed as follows: In the formula, , These are the synchronous calibration voltage sampling data and calibration current sampling data, respectively; This is the sampling point number.

[0041] Simultaneously, the absolute timestamp generated in step S1 is appended to the header of the current data packet. The packaged synchronous data stream is divided into two paths: one path is sent to the on-site power metering module; the other path is sent to the laboratory via the remote communication module. The two data paths are completely identical to ensure that the data originates from the same source.

[0042] like Figure 4 As shown, in step S5, AC power metering is performed at the field end. The on-site metrology module performs routine metrology procedures based on calibrated sampling data, including: The on-site power metering module receives calibration voltage sampling data. and calibration current sampling data The instantaneous power is calculated using the following expression: In the formula, For the first time on site The instantaneous power value at each sampling point.

[0043] Within the range specified by the absolute time label The on-site electricity metering value is obtained by accumulating and integrating the data. The expression is: In the formula, This is the on-site electricity metering value; This represents the total number of sampling points within the interval. The sampling interval; This is the instantaneous power sequence at the site.

[0044] On-site electricity meter readings The absolute time stamps are uploaded to the laboratory via a remote communication module.

[0045] Step S6: The laboratory performs analytical calculations of the reference electrical energy value. The laboratory receives synchronized calibration voltage sampling data. and calibration current sampling data Then, verify the absolute timestamp and extract the one that is completely consistent with the field data. Interval data.

[0046] An independent reference power analysis link is established, and the instantaneous power sequence is calculated using 64-bit double-precision floating-point arithmetic. The expression is as follows: In the formula, For the laboratory end The instantaneous power value of the laboratory at each sampling point; right Perform a composite Simpson numerical integral to calculate the reference energy value. The expression is: In the formula, This is the reference electrical energy value for the laboratory. This represents the total number of sampling points within the interval, which is set to an even number in this embodiment. The sampling interval; This is the laboratory instantaneous power sequence.

[0047] When accumulating over a long period, the Kahan summation algorithm is used to prevent the loss of rounding errors when accumulating a large number of decimals.

[0048] Step S7: Comparison of electrical energy values ​​and calculation of errors The laboratory-side power energy comparison module receives the on-site power energy metering values. and reference electrical energy value After matching and confirming the absolute time stamps, the relative error of electricity metering is calculated. The expression is: In the formula, This represents the relative error in on-site electricity metering.

[0049] Determine the absolute value of the relative error of on-site electricity metering Is it less than or equal to the preset allowable error limit? 0.2%. If yes, the calibration passes and the process ends; otherwise, the relative error of the on-site power metering is recorded. Proceed to step S8.

[0050] Step S8: Generate and feed back the corrected electricity metering parameters. The correction parameter generation module at the laboratory end generates parameters based on the on-site power meter readings. and reference electrical energy value Calculate the gain correction factor for electricity metering The expression is: In the formula, This is the gain correction factor.

[0051] It should be noted that this embodiment primarily focuses on gain correction. If historical data shows significant zero-point drift, the model can be expanded to... ,in This is the power metering offset correction coefficient, used to compensate for fixed background errors caused by factors such as device leakage current and ADC zero-point drift. It is obtained through multi-point load fitting. This is the current default setting for a single calibration. .

[0052] Gain correction factor The data is sent to the field via a remote communication module.

[0053] The gain correction factor will be applied at the field end. The parameters are written into the parameter storage area of ​​the electricity metering correction module, and the subsequent metering results are corrected using a gain correction coefficient. Perform a compensation update.

[0054] Step S9, Verification of calibration results and abnormal fuse breaking In the next adjacent metering interval after the parameter update, repeat steps S4 to S7 to obtain the field-corrected metering value. and corrected reference values .

[0055] Calculate verification error The expression is: like If so, the calibration is considered successful; Then, step S8 is executed again to recalculate the gain correction coefficient. And update the parameters at the field end.

[0056] Set the maximum number of iterations to 3 to avoid infinite loops.

[0057] If the number of iterations exceeds the maximum iteration threshold, the verification error will be affected. Still greater than the allowable error limit If the system fails to detect a hardware malfunction or exceeds the remote self-calibration capability of the equipment, it will output an abnormal status message and prompt manual intervention.

[0058] In one embodiment, the present invention provides a system for applying the above method, comprising: a field end and a laboratory end; The field terminal includes: Satellite signal receiver, used to receive time and frequency signals broadcast by satellite; Reference signal source, used to output reference voltage and reference current; The voltage-to-frequency conversion module has its input terminal connected to the voltage output terminal of the reference signal source, and is used to convert the reference voltage into a frequency signal. The counter module, whose input is connected to the output of the voltage-to-frequency conversion module and the satellite signal receiver, is used to use the calibration time base signal as the gate measurement frequency signal; The sampling circuit and analog-to-digital conversion module are used to synchronously sample and convert the injected reference voltage, reference current, and measured AC voltage and current. The power metering module, connected to the analog-to-digital conversion module, is used to calculate the on-site power metering value based on the calibrated sampling data. The laboratory side includes: A standard signal source, a voltage-to-frequency conversion module, and a frequency counting module are used to generate and measure the frequency signal corresponding to a standard voltage. The reference energy analysis and calculation module is used to receive synchronous sampling data sent by the field calibration terminal and perform high-precision numerical integration to calculate the reference energy value. The electrical energy value comparison and correction parameter generation module is connected to the reference electrical energy analysis and calculation module and the remote communication module, respectively, and is used to compare electrical energy metering values ​​and generate gain correction coefficients. Both the field end and the laboratory end include a remote communication module, which enables bidirectional transmission of time deviation data, frequency measurement data, synchronous sampling data, and gain correction coefficients.

[0059] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0060] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method of remotely self-calibrating AC power, the method comprising: include: Step S1: The field end and the laboratory end receive the time and frequency signal broadcast by the same satellite within the same observation window, measure the time difference between their respective local clocks and the satellite clock and exchange data, calculate the time deviation and average relative frequency deviation at both ends; compensate the local clock at the field end based on the time deviation and average relative frequency deviation, generate a calibration time base signal, and generate an absolute time tag for subsequent sampling data based on the calibration time base signal. Step S2: The field end converts the reference voltage into a frequency signal using the voltage-to-frequency conversion module, and performs frequency measurement using the calibration time base signal as a gate; the laboratory end performs synchronous measurement on the standard voltage; the voltage deviation is calculated based on the measurement results from both ends, and if the voltage deviation is within the preset threshold, the reference voltage is verified to be qualified. Step S3: Inject qualified reference voltage and reference current into the voltage sampling channel and current sampling channel at the field end, respectively, obtain the sampled values, and calculate the channel relative error; Calculate the corrected conversion coefficients based on the channel relative error; Step S4: The field end synchronously samples the AC voltage and current under test, performs point-by-point calibration using the corrected conversion coefficient, obtains calibration voltage sampling data and calibration current sampling data, and adds an absolute time tag; the synchronous data stream after adding the tag is divided into two paths, one path is sent to the field end, and the other path is sent to the laboratory end. Step S5: The field terminal calculates the instantaneous power based on the received synchronous data stream, and performs cumulative integration within the metering time interval specified by the absolute time tag to obtain the field power metering value. Step S6: The laboratory receives the synchronous data stream, verifies the absolute time tag to extract data consistent with the metering time interval, establishes an independent reference energy analysis link, uses high-precision floating-point arithmetic to calculate the instantaneous power sequence, and performs numerical integration calculation to obtain the reference energy value. Step S7: The laboratory compares the on-site power metering value with the reference power value and calculates the relative error of power metering. Step S8: When the relative error of electricity metering exceeds the preset allowable error limit, the laboratory calculates the electricity metering gain correction coefficient and sends it to the field. The field uses the gain correction coefficient to compensate and update the subsequent metering results.

2. The method according to claim 1, characterized in that, In step S1, generating a calibration time base signal includes: A moving average filter is applied to the continuously acquired time deviation sequence to obtain a smoothed time deviation estimate; The control parameters of the local oscillator at the field end are adjusted in real time using the average relative frequency deviation, so that the local clock frequency is close to the laboratory clock frequency. The adjusted local clock output is used as the calibration time base signal.

3. The method according to claim 1, characterized in that, In step S2, the voltage deviation is calculated. The expression is: In the formula, The voltage deviation between the reference voltage and the standard voltage; , These are the number of pulses counted within 1 second at the field end and the laboratory end, respectively. , These are the calibration conversion coefficients for the field-side and laboratory-side voltage-to-frequency conversion modules, respectively. , , respectively, are the differences between adjacent time intervals within the i-th second for the field end and the laboratory end.

4. The method according to claim 1, characterized in that, In step S3, the corrected conversion coefficient is calculated based on the channel relative error, and the expression is: In the formula, and These are the conversion coefficients for the corrected voltage and current paths, respectively; and These are the first-order linear compensation factors for the voltage channel and the current channel, respectively; and These are the voltage relative error and the current relative error, respectively.

5. The method according to claim 1, characterized in that, In step S6, the reference electrical energy value is obtained by performing numerical integration calculation, including: The reference electrical energy value was calculated using the composite Simpson numerical integration method. The expression is: In the formula, This is the reference electrical energy value for the laboratory. This represents the total number of sampling points within the interval. The sampling interval; This is a laboratory instantaneous power sequence; For long-term accumulation, the Kahan summation algorithm is used for error compensation accumulation.

6. The method according to claim 1, characterized in that, In step S8, the power metering gain correction coefficient is calculated. The expression is: In the formula, This is the gain correction factor; For reference electrical energy value; This is the on-site electricity metering value.

7. The method according to claim 1, characterized in that, It also includes step S9, in the next adjacent measurement interval after parameter update, repeating steps S4 to S7 to obtain the corrected field value and the new reference value, and calculating the verification error; If the verification error is still greater than the preset allowable error limit, then repeat step S8 to update the parameters; If the verification error still does not meet the requirements after the number of iterations exceeds the maximum iteration threshold, the field equipment is judged to be abnormal and abnormal status information is output.

8. A system applying the method of any one of claims 1-7, characterized in that, include: Field end and laboratory end; The field terminal includes: Satellite signal receiver, used to receive time and frequency signals broadcast by satellite; Reference signal source, used to output reference voltage and reference current; The voltage-to-frequency conversion module has its input terminal connected to the voltage output terminal of the reference signal source, and is used to convert the reference voltage into a frequency signal. The counter module, whose input is connected to the output of the voltage-to-frequency conversion module and the satellite signal receiver, is used to use the calibration time base signal as the gate measurement frequency signal; The sampling circuit and analog-to-digital conversion module are used to synchronously sample and convert the injected reference voltage, reference current, and measured AC voltage and current. The power metering module, connected to the analog-to-digital conversion module, is used to calculate the on-site power metering value based on the calibrated sampling data. The laboratory side includes: A standard signal source, a voltage-to-frequency conversion module, and a frequency counting module are used to generate and measure the frequency signal corresponding to a standard voltage. The reference energy analysis and calculation module is used to receive synchronous sampling data sent by the field calibration terminal and perform high-precision numerical integration to calculate the reference energy value. The electrical energy value comparison and correction parameter generation module is connected to the reference electrical energy analysis and calculation module and the remote communication module, respectively, and is used to compare electrical energy metering values ​​and generate gain correction coefficients. Both the field end and the laboratory end include a remote communication module, which enables bidirectional transmission of time deviation data, frequency measurement data, synchronous sampling data, and gain correction coefficients.

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