On-site calibrator for electric energy meter

Abstract

The invention discloses an electric energy meter on-site calibrator, and relates to the technical field of electric energy meter detection, a core architecture of an electric energy meter on-site calibrator calibration system is jointly formed through mutual cooperation of multiple groups of algorithm units, and average electric power P1 is obtained through calculation of multiple groups of calibration voltages and currents; according to the calibration method, measurement errors caused by a single test point can be avoided, and compared with a traditional fixed voltage calibration method, the calibration method can comprehensively reflect the performance of the electric energy meter under different voltage conditions, so that the calibration accuracy of the electric energy meter is improved, the accuracy of the electric energy meter in actual use is ensured, and the calibration efficiency is improved. The harmonic influence coefficient Hoe and the temperature change are brought into the adjusted electric power algorithm unit to calculate the adjusted electric power P2, so that the influence of the harmonic and the temperature change on the verification result can be corrected, and the verification electric energy of the electric energy meter is closer to the electric energy actually consumed by the electric energy meter. Therefore, high electric energy meter verification accuracy can be ensured under various working conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of electricity meter detection, and specifically relates to an on-site calibrator for electricity meters. Background Art

[0002] The electricity meter is an important part of the power system and is used to measure the consumption of electric energy and calculate the electricity bill. However, over time and with the increase in service life, the accuracy of the electricity meter may be affected, and calibration is required to ensure its accuracy and reliability.

[0003] For example, an on-site calibrator management system and method for electricity meters disclosed in Chinese invention CN202310693384.9 optimizes the process of detecting electricity meters based on an on-site calibrator, realizes automatic acquisition of electricity meter parameters and automatic detection of electricity meters, and a digital electricity meter on-site calibration method and device disclosed in Chinese invention CN201710884469.X. This calibration device uses a specific pulse acquisition method and uses an FPGA parallel system for pulse acquisition calibration. The total system error of electricity pulse calibration is less than two high-frequency pulses, and it can quickly and accurately detect the measurement error of the calibrated digital electricity meter.

[0004] For the calibration of first-class electricity meters in the current prior art, such as the above-cited documents, the calibration voltage output by the calibrator is generally 220V, which is the same as the civil voltage. However, in the actual process of civil electricity use, the voltage will fluctuate. Especially during peak electricity consumption, it is difficult for the conventional calibration method to change the voltage output by the calibrator to simulate the counting situation of the electricity meter when the voltage fluctuates. This single calibration method is prone to calibration errors.

[0005] In the calibration of electricity meters, changes in temperature will affect the calibration of electricity meters, and harmonics will also cause distortion of the current waveform and distortion of the core magnetic flux density waveform, resulting in non-linear changes in the area of the hysteresis loop, thus affecting the calibration of electricity meters. The calibration meters in the prior art are difficult to consider the influence of temperature changes and harmonics on calibration.

[0006] Therefore, there is an urgent need for an on-site calibrator for electricity meters to solve the above problems. Summary of the Invention

[0007] The purpose of the present invention is to provide an on-site calibrator for electricity meters to solve the problems raised in the above background art.

[0008] To achieve the above purpose, the present invention provides the following technical solution: An on-site calibrator for electricity meters, comprising: a calibration system;

[0009] The calibration system specifically includes:

[0010] A data collection module for collecting the calibration data of the electricity meter;

[0011] A data preprocessing module for decoding and preprocessing the data information in the database to obtain the parameters participating in the calculation in the calculation processing module;

[0012] The calculation processing module, and the specific calculation processing steps are as follows:

[0013] S1 is used to input the parameters obtained after decoding and preprocessing into the average electric power algorithm unit to calculate the average electric power P1;

[0014] S2 inputs the average electric power P1 into the adjusted electric power algorithm unit in the calculation processing module, combines the harmonic influence term and the temperature deviation influence term to calculate the adjusted electric power P2, and uploads it to the database;

[0015] S3 is used to calculate the electricity meter energy value Wmeter in the database according to the adjusted electric power P2 and the time of the input voltage during calibration;

[0016] S4 calculates the relative error Re of the electricity meter according to the electricity meter energy value Wmeter and the standard energy value Wstd output by the calibrator. Specifically:

[0017] When calibrating and detecting a Class 1 electricity meter, when the relative error Re of the electricity meter ≤ 1%, subsequent electricity meter pulse calibration is carried out;

[0018] When 1% ≤ the relative error Re of the electricity meter ≤ 3%, the parameter values in the adjusted electric power algorithm unit are adjusted in the database through the feedback adjustment unit, and the calculation in the calculation processing module is carried out again;

[0019] When the relative error Re of the electricity meter ≥ 3%, the electricity meter is repaired or replaced.

[0020] Optionally, the collection of the electricity meter calibration data specifically includes:

[0021] Obtain the actual voltage Van and actual current Ian through real-time monitoring of the electricity meter;

[0022] Obtain the rated voltage Vrn and rated current Irn through a programmable AC power supply;

[0023] Obtain the offset value Ih of the h-th harmonic, the highest harmonic order H to be compensated, and the harmonic order h through an FFT spectrum analyzer;

[0024] Obtain the actual temperature Ta through real-time monitoring of the temperature sensor;

[0025] And upload them to the database together.

[0026] Optionally, the adjustment of the parameter values in the adjusted electric power algorithm unit specifically includes:

[0027] Input the adjusted electric power P2 and the electric energy value Wmeter of the electric energy meter into the compensation coefficient adjustment value algorithm unit in the calculation and processing module to calculate the adjusted temperature compensation coefficient αnew and the adjusted harmonic compensation coefficient β new , and recalculate in the calculation and processing module.

[0028] Optionally, the calculation and processing module includes an average electric power algorithm unit, an adjusted electric power algorithm unit, a compensation coefficient adjustment value algorithm unit, and a feedback adjustment unit.

[0029] Optionally, the average electric power algorithm unit is as follows:

[0030]

[0031] Where:

[0032] P1 represents the average electric power:

[0033] N represents the number of times of calibration voltage output;

[0034] Van represents the actual voltage, which is the voltage value received in the electric energy meter when the voltage is output for the nth time;

[0035] Ian represents the actual current, which is the current value received in the electric energy meter when the voltage is output for the nth time;

[0036] Vrn represents the rated voltage, which is the rated voltage value output by the programmable AC power supply when the voltage is output for the nth time;

[0037] Irn represents the rated current, which is the rated current value output by the programmable AC power supply when the voltage is output for the nth time;

[0038] The rated voltage Vrn always satisfies:

[0039]

[0040] This part, by dividing the actual voltage Van by the rated voltage Vrn, represents the influence term of voltage deviation in the calculation of the average electric power P1. In the electric energy meter, the deviation of the voltage from the rated value will cause the driving force of the electromagnetic element to change non-linearly and affect the measurement accuracy. This part amplifies the influence of the voltage deviation value on the average electric power P1 through the power function of the voltage deviation;

[0041] This part is obtained by dividing the actual current Ian by the rated current Irn, representing the influencing term of the current deviation in the calculation of the average electric power P1. In the watt-hour meter, the current affects the device accuracy through thermal effects and electromagnetic interference. This part amplifies the influence of the current deviation value on the average electric power P1 through the power function of the voltage deviation.

[0042] By multiplying the actual voltage Van by the actual current Ian and then multiplying by the voltage deviation term and the current deviation term the electric power of the watt-hour meter at the nth calibration is obtained. After adding up the electric powers obtained from N calibrations, the total electric power is obtained, and then divided by the number of calibration voltage outputs N to obtain the average electric power P1.

[0043] Optionally, the adjusted electric power algorithm unit is as follows:

[0044] P2 = P1 × exp(α × |Ta - Ts|) × (1 + β × Hoe)

[0045] Where:

[0046] P2 represents the adjusted electric power;

[0047] P1 represents the average electric power;

[0048] Ta represents the actual temperature;

[0049] Ts represents the standard temperature, with a preset value of 25;

[0050] α represents the temperature compensation coefficient, with a default value of 0.1;

[0051] Hoe represents the harmonic influence coefficient;

[0052] β represents the harmonic compensation coefficient, with a default value of 0.1;

[0053] This part of |Ta - Ts| uses the absolute difference between the actual temperature Ta and the standard temperature Ts as the exponential part of the natural constant e to reflect the non-linear influence of temperature change on the calculation of the adjusted electric power P2. As the absolute difference between the actual temperature Ta and the standard temperature Ts in this part increases, the calculated value of this part of exp(α × |Ta - Ts|) increases, thereby increasing the calculated adjusted electric power P2;

[0054] The spectrum of the test signal is analyzed by an FFT spectrum analyzer. It is set that harmonics with an amplitude exceeding 0.5% of the fundamental wave need to be compensated. When the current is a pure sine wave, Hoe = 0, and this part of 1 + β × Hoe is 1, without additional compensation.

[0055] Optionally, the calculation formula of the harmonic influence coefficient Hoe is as follows:

[0056]

[0057] Wherein:

[0058] Hoe represents the harmonic influence coefficient;

[0059] Ih represents the offset value of the h-th harmonic;

[0060] H represents the highest harmonic order to be compensated;

[0061] h represents the harmonic order;

[0062] Regarding the numerator When the harmonic order h = 1, it represents the fundamental wave, which is the main energy carrier of the power system. When the harmonic order h ranges from 2 to 5, the 2nd to 5th harmonics are the low-order harmonics with the highest proportion in industrial and civil scenarios. The sum-of-squares operation linearly superimposes the amplitude energies of each harmonic, reflecting the total pollution degree of the low-order harmonics;

[0063] Regarding the denominator It is the sum of the squares of the harmonic currents weighted by order, This part eliminates the influence of the absolute magnitude of the harmonic amplitude by the ratio of the numerator part divided by the denominator part, and calculates the harmonic influence coefficient Hoe through the order distribution characteristics.

[0064] Optionally, the compensation coefficient adjustment value algorithm unit is as follows:

[0065]

[0066]

[0067] Wherein:

[0068] α new represents the adjusted temperature compensation coefficient;

[0069] β new represents the adjusted harmonic compensation coefficient;

[0070] α represents the temperature compensation coefficient;

[0071] β represents the harmonic compensation coefficient;

[0072] Hoe represents the harmonic influence coefficient;

[0073] Pstd represents the standard electric power;

[0074] P2 represents the adjusted electric power;

[0075] Ta represents the actual temperature;

[0076] Ts represents the standard temperature, and the preset value is 25;

[0077] Re represents the relative error of the electricity meter, and the calculation formula is as follows:

[0078]

[0079] Where:

[0080] Wstd represents the standard electricity value;

[0081] Wmeter represents the electricity value of the electricity meter;

[0082] This part standardizes the deviation between the adjusted electric power P2 and the standard electric power Pstd by dividing the difference between the standard electric power Pstd and the adjusted electric power P2 by the standard electric power Pstd, and directly affects the adjusted temperature compensation coefficient α new , as the deviation between the adjusted electric power P2 and the standard electric power Pstd increases, the calculated adjusted temperature compensation coefficient α new becomes larger;

[0083] The numerator |Ta - Ts| in this part represents the absolute deviation between the actual temperature and the standard temperature, The denominator part is a deformation of the Sigmoid function, which is used to control the excessive influence at extreme temperatures. Dividing the numerator part by the denominator, this This part as a whole represents the effective influence value of the temperature deviation on the adjusted temperature compensation coefficient α new ;

[0084] This part represents the relative error of electricity in the electricity meter calibration by dividing the absolute difference between the standard electricity value Wstd and the electricity value Wmeter of the electricity meter by the electricity value Wmeter of the electricity meter.

[0085] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0086] First, the calibration system in the calibrator of the present invention, through the mutual cooperation of multiple algorithm units, jointly constitutes the core architecture of the on-site calibrator calibration system for electricity meters. By combining the calibration output voltages multiple times and calculating the average electric power P1 through multiple groups of calibration voltages and currents, it can avoid measurement errors caused by a single test point. This calibration method can more comprehensively reflect the performance of the electricity meter under different voltage conditions compared with the traditional fixed-voltage calibration method, thereby improving the accuracy of electricity meter calibration, helping to discover potential problems of the electricity meter under different working conditions, and ensuring its accuracy in actual use.

[0087] Second, by incorporating the harmonic influence coefficient Hoe into the adjusted electric power algorithm unit and calculating the adjusted electric power P2, the present invention can correct the influence of harmonics on the verification result, making the verified electric energy of the watt-hour meter closer to the actual consumed electric energy of the watt-hour meter. By incorporating the temperature influence term into the adjusted electric power algorithm unit, the influence of temperature change on the measurement result of the watt-hour meter can be corrected, thereby enabling the performance of the watt-hour meter under harmonics and temperature changes to be evaluated during the watt-hour meter verification process, ensuring a high verification accuracy of the watt-hour meter under various working conditions.

[0088] Third, in the compensation coefficient adjustment value algorithm unit, the present invention dynamically adjusts the values of the temperature compensation coefficient α and the harmonic compensation coefficient β in the adjusted electric power algorithm unit through real-time power deviation and electric energy deviation, enabling the verification system to more accurately adjust the influence degrees of temperature and harmonics on the adjusted electric power P2 according to the actual environmental conditions, thereby improving the adaptability of the verification system. Through dynamic parameter adjustment, the watt-hour meter verification of the calibrator is upgraded from "passive detection in a fixed mode" to "active calibration adaptable to the environment", providing a core algorithm guarantee for high-precision metering in smart grids. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] Figure 1 is a flowchart of a verification system for an on-site watt-hour meter calibrator;

[0090] Figure 2 is a schematic diagram of the overall structure of a verification system for an on-site watt-hour meter calibrator. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0091] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0092] Embodiment 1. Please refer to Figures 1 to 2 , the present invention provides an on-site watt-hour meter calibrator, including a verification system;

[0093] The verification system specifically includes:

[0094] A data collection module for collecting watt-hour meter verification data, specifically including:

[0095] Obtaining the actual voltage Van and actual current Ian through real-time monitoring of the watt-hour meter;

[0096] Obtaining the rated voltage Vrn and rated current Irn through a programmable AC power supply;

[0097] Obtain the offset value $I_h$ of the $h$-th harmonic, the highest harmonic order $H$ to be compensated, and the harmonic order $h$ through an FFT spectrum analyzer;

[0098] Obtain the actual temperature $T_a$ by real-time monitoring through a temperature sensor;

[0099] And upload them to the database together;

[0100] A data preprocessing module for decoding and preprocessing the data information in the database to obtain the parameters for calculation in the calculation processing module;

[0101] The calculation processing module, and the specific calculation processing steps are as follows:

[0102] S1 is used to input the parameters obtained after decoding and preprocessing into the average electric power algorithm unit to calculate the average electric power $P_1$;

[0103] S2 inputs the average electric power $P_1$ into the adjusted electric power algorithm unit in the calculation processing module, combines the harmonic influence term and the temperature deviation influence term to calculate the adjusted electric power $P_2$, and uploads it to the database;

[0104] S3, in the database, calculates the electric energy value $W_{meter}$ of the electric energy meter according to the adjusted electric power $P_2$ and the time of the input voltage during calibration;

[0105] S4 calculates the relative error $R_e$ of the electric energy meter according to the electric energy value $W_{meter}$ of the electric energy meter and the standard electric energy value $W_{std}$ output by the calibrator. Specifically:

[0106] When calibrating and detecting a Class 1 electric energy meter, when the relative error $R_e$ of the electric energy meter is $\leq 1\%$, perform subsequent pulse calibration of the electric energy meter;

[0107] When $1\% \leq R_e \leq 3\%$ of the relative error of the electric energy meter, adjust the parameter values in the adjusted electric power algorithm unit in the database through the feedback adjustment unit, and recalculate in the calculation processing module;

[0108] When the relative error $R_e$ of the electric energy meter is $\geq 3\%$, repair or replace the electric energy meter.

[0109] In this embodiment:

[0110] In the verification system within the verifier of the present invention, through the mutual cooperation of multiple algorithm units, the core architecture of the verification system of the on-site electric energy meter verifier is formed. By combining the verification output voltages multiple times and calculating the average electric power P1 through multiple groups of verification voltages and currents, it is possible to avoid measurement errors caused by a single test point. This verification method can more comprehensively reflect the performance of the electric energy meter under different voltage conditions, thereby improving the accuracy of electric energy meter verification. Traditional verification methods may only focus on the performance of the electric energy meter under specific voltages or currents, while the new verification method can more comprehensively evaluate the performance of the electric energy meter through multiple measurements and average calculations. This helps to discover potential problems of the electric energy meter under different working conditions and ensure its accuracy in actual use.

[0111] Moreover, during the actual operation of the electric energy meter, due to the existence of harmonics, the current waveform will be distorted, thus affecting the measurement accuracy of the electric energy meter. By incorporating the harmonic influence coefficient Hoe into the calculation of the adjusted electric power algorithm unit and calculating the adjusted electric power P2, it is possible to correct the influence of harmonics on the verification result and make the verification value of the electric energy meter closer to the actual electric energy consumed by the electric energy meter. By incorporating the temperature influence term into the calculation of the adjusted electric power algorithm unit and calculating the adjusted electric power P2, it is possible to correct the influence of temperature changes on the measurement result of the electric energy meter, thereby being able to evaluate the performance of the electric energy meter under harmonics and temperature changes during the electric energy meter verification process to ensure a high accuracy of electric energy meter verification under various working conditions.

[0112] Please refer to Figures 1 to 2 , the average electric power algorithm unit is as follows:

[0113]

[0114] Where:

[0115] P1 represents the average electric power:

[0116] N represents the number of times of verification voltage output;

[0117] Van represents the actual voltage, which is the voltage value received inside the electric energy meter during the nth voltage output and is obtained through real-time monitoring of the electric energy meter;

[0118] Ian represents the actual current, which is the current value received inside the electric energy meter during the nth voltage output and is obtained through real-time monitoring of the electric energy meter;

[0119] Vrn represents the rated voltage, which is the rated voltage value output by the programmable AC power supply during the nth voltage output;

[0120] Irn represents the rated current, which is the rated current value output by the programmable AC power supply during the nth voltage output;

[0121] The rated voltage Vrn always satisfies:

[0122]

[0123] Wherein:

[0124] This part represents the influence term of voltage deviation in the calculation of average electric power P1 by dividing the actual voltage Van by the rated voltage Vrn. In an electricity meter, voltage deviation from the rated value will cause non-linear change in the driving force of electromagnetic components and affect the measurement accuracy. This part amplifies the influence of the voltage deviation value on the average electric power P1 through the power function of the voltage deviation;

[0125] This part represents the influence term of current deviation in the calculation of average electric power P1 by dividing the actual current Ian by the rated current Irn. In an electricity meter, current affects the equipment accuracy through thermal effect and electromagnetic interference. This part amplifies the influence of the current deviation value on the average electric power P1 through the power function of the voltage deviation;

[0126] By multiplying the actual voltage Van by the actual current Ian and then by the voltage deviation term and the current deviation term the electric power of the electricity meter at the nth calibration is obtained. After adding up the electric powers obtained from N calibrations, the total electric power is obtained, and then divided by the number of calibration voltage outputs N to obtain the average electric power P1;

[0127] In this embodiment:

[0128] The average electric power algorithm unit combines the influence of current deviation and voltage deviation in the electricity meter calibration, combines the calibration output voltages for multiple times, and calculates the average electric power P1 through multiple groups of calibration voltages and currents, which can avoid measurement errors caused by a single test point. This calibration method can more comprehensively reflect the performance of the electricity meter under different voltage conditions, thereby improving the accuracy of electricity meter calibration. The average electric power algorithm unit also comprehensively considers the influence terms of current deviation and voltage deviation, which means that when calculating the average electric power, not only the actual values of voltage and current are considered, but also the degree of their deviation from the rated values. This comprehensive consideration can more accurately evaluate the performance of the electricity meter in actual use. Traditional calibration methods may only focus on the performance of the electricity meter under specific voltages or currents, while the new calibration method can more comprehensively evaluate the performance of the electricity meter through multiple measurements and average calculations. This helps to discover potential problems of the electricity meter under different working conditions and ensure its accuracy in actual use.

[0129] In summary, through multiple measurements and average calculations, the new calibration method can reduce the impact of single measurement errors or abnormal performances under specific working conditions on the final result, which helps to improve the reliability of the calibration result and reduce the error risk.

[0130] Please refer to Figures 1 to 2 , the adjusted electric power algorithm unit is as follows:

[0131] P2 = P1 × exp(α × |Ta - Ts|) × (1 + β × Hoe)

[0132] Where:

[0133] P2 represents the adjusted electric power;

[0134] P1 represents the average electric power;

[0135] Ta represents the actual temperature;

[0136] Ts represents the standard temperature, with a preset value of 25;

[0137] α represents the temperature compensation coefficient, with a default value of 0.1, which can be self-adjusted in the calibration system;

[0138] Hoe represents the harmonic influence coefficient;

[0139] β represents the harmonic compensation coefficient, with a default value of 0.1, which can be self-adjusted in the calibration system;

[0140] In the formula calculation:

[0141] Both too high or too low ambient temperature will affect the performance of the internal components of the watt-hour meter, especially the resistance components in the watt-hour meter. The resistivity of metal increases with the increase of temperature, which leads to the resistance value deviation of the current sampling resistor and affects the current measurement accuracy. The part of |Ta - Ts| uses the absolute difference between the actual temperature Ta and the standard temperature Ts as the exponential part of the natural constant e to reflect the non-linear influence of temperature change on the calculation of the adjusted electric power P2. As the absolute difference between the actual temperature Ta and the standard temperature Ts of the part of |Ta - Ts| increases, the calculated value of exp(α × |Ta - Ts|) increases, thereby increasing the calculated adjusted electric power P2;

[0142] In the verification of watt-hour meters, harmonics can cause distortion of the current waveform, which in turn causes distortion of the magnetic flux density waveform in the iron core, leading to non-linear changes in the area of the hysteresis loop. When the current is a pure sine wave, Hoe = 0, and the part of 1 + β×Hoe is 1, without additional compensation. The spectrum of the test signal is analyzed by an FFT spectrum analyzer. Harmonics with an amplitude exceeding 0.5% of the fundamental wave need to be compensated. The harmonic order h to be compensated is automatically identified by the FFT analyzer, and the highest harmonic order H to be compensated is determined. This is a relatively mature existing technology in the field of harmonic analysis and will not be elaborated here.

[0143] The calculation formula for the harmonic influence coefficient Hoe is as follows:

[0144]

[0145] Where:

[0146] Hoe represents the harmonic influence coefficient;

[0147] Ih represents the offset value of the h-th harmonic, which is obtained by an FFT spectrum analyzer;

[0148] H represents the highest harmonic order to be compensated, which is obtained by an FFT spectrum analyzer;

[0149] h represents the harmonic order, which is obtained by an FFT spectrum analyzer;

[0150] In the formula calculation:

[0151] Regarding the numerator When the harmonic order h = 1, it represents the fundamental wave, which is the main energy carrier of the power system. When the harmonic order h takes values from 2 to 5, the 2nd to 5th harmonics are the low-order harmonics with the highest proportion in industrial and civil scenarios. The sum-of-squares operation linearly superimposes the amplitudes of each harmonic, reflecting the total pollution degree of the low-order harmonics;

[0152] Regarding the denominator It is the sum of the squares of the harmonic currents weighted by order, This part eliminates the influence of the absolute magnitude of the harmonic amplitude through the ratio of the numerator part divided by the denominator part, and calculates the harmonic influence coefficient Hoe through the order distribution characteristics;

[0153] In this embodiment:

[0154] During the actual operation of the electricity meter, due to the existence of harmonics, the current waveform will be distorted, which will affect the measurement accuracy of the electricity meter. By incorporating the harmonic influence coefficient Hoe into the calculation of the adjusted electric power algorithm unit and calculating the adjusted electric power P2, the influence of harmonics on the calibration result can be corrected, making the calibration value of the electricity meter closer to the actual power consumption of the electricity meter. It can also provide more accurate data support for the subsequent monitoring, management, and billing of the power system. The performance of the electricity meter is affected by temperature. The deviation of the actual temperature Ta from the standard temperature Ts will cause errors in the calibration of the electricity meter. By incorporating the temperature influence term into the calculation of the adjusted electric power algorithm unit and calculating the adjusted electric power P2, the influence of temperature changes on the measurement result of the electricity meter can be corrected, further improving the calibration accuracy.

[0155] By calculating the adjusted electric power P2 through the adjusted electric power algorithm unit, the performance of the electricity meter under harmonics and temperature changes can be evaluated during the calibration process of the electricity meter, so as to ensure high calibration accuracy of the electricity meter under various working conditions.

[0156] Multiplying the calculated adjusted electric power P2 by the time of the input voltage during calibration can obtain the electricity value Wmeter of the electricity meter. Based on this electricity value, subsequent pulse calibration of the electricity meter is carried out, specifically including:

[0157] Connect the pulse output terminal of the electricity meter to the input terminal of the calibrator with a special pulse line;

[0158] Input parameters such as the pulse constant (such as 1600 imp / kWh), voltage, and current transformation ratio of the electricity meter into the calibrator;

[0159] Set the preset number of pulses (1000). The calibrator simultaneously records the actual number of pulses and the standard number of pulses of the electricity meter and calculates the error;

[0160] The calibrator automatically compares the measured number of pulses with the theoretical number of pulses, calculates the result according to the error formula, and rounds it to the specified decimal place.

[0161] The pulse calibration of the electricity meter is a relatively mature existing technology, so it will not be described in detail here.

[0162] Please refer to Figures 1 to 2 , the compensation coefficient adjustment value algorithm unit is as follows:

[0163]

[0164] Among them:

[0165] α new represents the adjusted temperature compensation coefficient;

[0166] β new represents the adjusted harmonic compensation coefficient;

[0167] α represents the temperature compensation coefficient;

[0168] β represents the harmonic compensation coefficient;

[0169] Hoe represents the harmonic influence coefficient;

[0170] Pstd represents the standard electric power, which is calculated from the rated voltage of 220V and the rated current output by the calibrator. Specifically: standard electric power = rated voltage × rated current × phase angle between current and voltage;

[0171] P2 represents the adjusted electric power;

[0172] Ta represents the actual temperature;

[0173] Ts represents the standard temperature, with a preset value of 25;

[0174] Re represents the relative error of the electricity meter, and the calculation formula is as follows:

[0175]

[0176] Where:

[0177] Wstd represents the standard electricity value, which is obtained from the internal data of the calibrator and is the standard value for calibrating the electricity value;

[0178] Wmeter represents the electricity value of the electricity meter;

[0179] In the formula calculation:

[0180] This part normalizes the deviation between the adjusted electric power P2 and the standard electric power Pstd by dividing the difference between the standard electric power Pstd and the adjusted electric power P2 by the standard electric power Pstd, and directly affects the adjusted temperature compensation coefficient α new , as the deviation between the adjusted electric power P2 and the standard electric power Pstd increases, the calculated adjusted temperature compensation coefficient α new becomes larger;

[0181] The numerator |Ta - Ts| in this part represents the absolute deviation between the actual temperature and the standard temperature, The denominator part is a deformation of the Sigmoid function, which is used to control the excessive influence under extreme temperatures. Dividing the numerator part by the denominator, this This part as a whole represents the effective influence value of the temperature deviation on the adjusted temperature compensation coefficient α new ;

[0182] This part represents the relative error of electric energy in the verification of the electric energy meter by dividing the absolute difference between the standard electric energy value Wstd and the electric energy value Wmeter of the electric energy meter by the electric energy value Wmeter of the electric energy meter;

[0183] In this embodiment:

[0184] During the on-site verification of the electric energy meter by the calibrator, the voltage and current characteristic curves of the electric energy meter are non-linear when deviating from the rated value (such as iron core magnetic saturation, thermal effect, etc.), and the traditional compensation model with fixed parameters cannot cover the full range. The compensation coefficient adjustment value algorithm unit dynamically adjusts the values of the temperature compensation coefficient α and the harmonic compensation coefficient β in the adjusted electric power algorithm unit through real-time power deviation and electric energy deviation, so that the verification system can more accurately adjust the influence degrees of temperature and harmonics on the adjusted electric power P2 according to the actual environmental conditions (such as sudden cooling during outdoor verification, such as harmonic mutation caused by the start and stop of inverters in new energy power stations, etc.), thereby improving the adaptability of the verification system. Through dynamic parameter adjustment, the electric energy meter verification of the calibrator is upgraded from "passive detection in a fixed mode" to "active calibration with environmental adaptability", providing a core algorithm guarantee for high-precision metering in smart grids.

[0185] The influence of temperature on the electric energy meter is a complex process. The measurement errors of the electric energy meter may be different at different temperatures. By dynamically adjusting the temperature compensation coefficient, the algorithm module can more precisely correct the influence of temperature on the measurement result of the electric energy meter according to the actual temperature change, thereby improving the accuracy of the measurement result. Harmonics will cause distortion of the current waveform and affect the measurement accuracy of the electric energy meter. Dynamically adjusting the harmonic compensation coefficient can more effectively suppress harmonic interference according to the actual content of harmonics, making the measured value of the electric energy meter closer to the actual consumed electric energy. Moreover, the sensitivities of different models and brands of electric energy meters to temperature and harmonics may vary. Dynamically adjusting the compensation coefficient can enable the algorithm module to better adapt to the characteristics of different electric energy meters and ensure accurate verification of various electric energy meters.

[0186] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirits of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A field calibrator for electric energy meter, characterized in that: include: Verification system; The verification system specifically comprises: Data collection module, used for collecting electric energy meter calibration data; The data preprocessing module is used to decode and preprocess the data information in the database to obtain the parameters involved in the calculation in the calculation processing module; Calculation processing module, the specific calculation processing steps are as follows: S1, used to input the parameters obtained after decoding preprocessing into the average electric power algorithm unit to calculate the average electric power P1; S2, input the average electric power P1 into the adjusted electric power algorithm unit in the calculation processing module, combine the harmonic influence term and the temperature deviation influence term to calculate the adjusted electric power P2, and upload it to the database; S3, in the database, calculating the electric energy value Wmeter of the electric energy meter according to the adjusted electric power P2 and the time of the input voltage during the calibration; S4, calculate the relative error Re of the energy meter according to the energy value Wmeter of the energy meter and the standard energy value Wstd output by the calibrator. Specifically: Check and test the level 1 electric energy meter. When the relative error Re of the electric energy meter is less than or equal to 1%, perform subsequent electric energy meter pulse check. When the relative error Re of the electric energy meter is 1%≤3%, the parameter value in the adjusted electric power algorithm unit is adjusted in the database through the feedback adjustment unit, and the calculation in the calculation processing module is re-performed; When the relative error Re of the electric energy meter is ≥ 3%, the electric energy meter should be repaired or replaced.

2. The electric energy meter field calibrator according to claim 1, characterized in that: The collection of the electric energy meter verification data specifically includes: Obtain the actual voltage Van and actual current Ian through real-time monitoring of the electric energy meter; Obtain the rated voltage Vrn and the rated current Irn through a programmable AC power supply; Obtain the offset value Ih of the hth harmonic, the highest harmonic order H to be compensated, and the harmonic order h through the FFT spectrum analyzer; The actual temperature Ta is obtained through real-time monitoring by the temperature sensor; And upload them to the database together.

3. The electric energy meter field calibrator according to claim 1, characterized in that: The adjustment of the parameter value in the adjusted electric power algorithm unit specifically includes: The adjusted electric power P2 and the electric energy value Wmeter of the electric energy meter are input into the compensation coefficient adjustment value algorithm unit in the calculation processing module to calculate the adjusted temperature compensation coefficient α new And the adjusted harmonic compensation coefficient β new , and re-calculate in the calculation processing module.

4. The electric energy meter field calibrator according to claim 1, characterized in that: The calculation processing module includes an average electric power algorithm unit, an adjusted electric power algorithm unit, a compensation coefficient adjustment value algorithm unit and a feedback adjustment unit.

5. The electric energy meter field tester according to claim 4, characterized in that: The average electric power algorithm unit is as follows: in: P1 represents the average electrical power: N represents the number of times the calibration voltage is output; Van represents the actual voltage, which is the voltage value received in the electric energy meter when the nth voltage is output; Ian represents the actual current, which is the current value received in the energy meter when the nth voltage is output; Vrn represents the rated voltage, which is the rated voltage value output by the programmable AC power supply when the voltage is output for the nth time; Irn represents the rated current, which is the rated current value output by the programmable AC power supply when the nth voltage is output; The rated voltage Vrn always satisfies: This part is calculated by dividing the actual voltage Van by the rated voltage Vrn, which represents the influence of voltage deviation in the calculation of average electric power P1. In the electric energy meter, the voltage deviation from the rated value will cause nonlinear changes in the driving force of the electromagnetic component and affect the measurement accuracy. This part amplifies the influence of the voltage deviation value on the average electric power P1 through the power function of the voltage deviation; This part is obtained by dividing the actual current Ian by the rated current Irn, which represents the influence of the current deviation in the calculation of the average electric power P1. In the electric energy meter, the current affects the accuracy of the equipment through thermal effects and electromagnetic interference. This part amplifies the effect of the current deviation on the average electric power P1 through the power function of the voltage deviation; By multiplying the actual voltage Van by the actual current Ian and then by the voltage deviation term and the current deviation term The electric power of the electric energy meter at the time of the nth calibration is obtained, the electric power obtained by N calibrations is added to obtain the total electric power, and then divided by the number of calibration voltage outputs N to obtain the average electric power P1.

6. The electric energy meter field tester according to claim 5, characterized in that: The adjusted electric power algorithm unit is as follows: P2=P1×exp(α×|Ta-Ts|)×(1+β×Hoe) in: P2 represents the adjusted electric power; P1 represents the average electrical power; Ta represents the actual temperature; Ts represents the standard temperature, and the preset value is 25; α represents the temperature compensation coefficient, the default value is 0.1; Hoe represents the harmonic influence coefficient; β represents the harmonic compensation coefficient, and the default value is 0.1; The part |Ta-Ts| uses the absolute difference between the actual temperature Ta and the standard temperature Ts as the exponential part of the natural constant e to reflect the nonlinear effect of temperature change on the calculation of the adjusted electric power P2. As the absolute difference between the actual temperature Ta and the standard temperature Ts increases, the calculated value of exp(α×|Ta-Ts|) increases, thereby increasing the calculated adjusted electric power P2. The spectrum of the test signal is analyzed by FFT spectrum analyzer, and the harmonics with amplitude exceeding 0.5% of the fundamental wave are set to be compensated. When the current is a pure sine wave, Hoe=0, 1+β×Hoe is 1, and no additional compensation is required.

7. The electric energy meter field tester according to claim 6, characterized in that: The calculation formula of the harmonic influence coefficient Hoe is as follows: in: Hoe represents the harmonic influence coefficient; Ih represents the offset value of the hth harmonic; H represents the highest harmonic order to be compensated; h represents the harmonic order; About the molecule When the harmonic order h=1, it represents the fundamental wave, which is the main energy carrier of the power system. When the harmonic order h is 2-5, the 2nd to 5th harmonics are the low-order harmonics with the highest proportion in industrial and civil scenarios. The square sum operation linearly superimposes the amplitude energy of each harmonic to reflect the total pollution degree of the low-order harmonics. About the denominator is the sum of squares of harmonic currents weighted by order, This part eliminates the influence of the absolute magnitude of the harmonic amplitude by dividing the numerator by the denominator, and calculates the harmonic influence coefficient Hoe through the order distribution characteristics.

8. The electric energy meter field calibrator according to claim 7, characterized in that: The compensation coefficient adjustment value algorithm unit is as follows: in: α new Represents the adjusted temperature compensation coefficient; β new Represents the adjusted harmonic compensation coefficient; α represents the temperature compensation coefficient; β represents the harmonic compensation coefficient; Hoe represents the harmonic influence coefficient; Pstd stands for standard electrical power; P2 represents the adjusted electric power; Ta represents the actual temperature; Ts represents the standard temperature, and the preset value is 25; Re represents the relative error of the electric energy meter, and the calculation formula is as follows: in: Wstd stands for standard electric energy value; Wmeter represents the energy value of the energy meter; This part normalizes the deviation between the adjusted power P2 and the standard power Pstd by dividing the difference between the standard power Pstd and the adjusted power P2 by the standard power Pstd, and directly affects the adjusted temperature compensation coefficient α new As the deviation between the adjusted power P2 and the standard power Pstd increases, the calculated adjusted temperature compensation coefficient α new The bigger; The numerator |Ta-Ts| in this part represents the absolute deviation of the actual temperature from the standard temperature. The denominator is a variation of the Sigmoid function, which is used to control the excessive impact under extreme temperatures. The numerator is divided by the denominator. This part represents the overall effect of temperature deviation on the adjusted temperature compensation coefficient α new The effective impact value of This part is obtained by subtracting the absolute difference between the standard energy value Wstd and the energy meter value Wmeter and dividing it by the energy meter value Wmeter, which represents the relative error of the energy in the energy meter calibration.

Images