A production calibration method for a high-precision AC energy meter

Abstract

The present invention relates to a production calibration method for a high-precision AC energy meter, comprising the following steps: calibrating the produced energy meter; testing the energy meter to obtain test data A, and the energy meters that pass the test enter the aging process, while the unqualified ones are repaired and then tested again; aging the energy meter to obtain aging data, adjusting the aging time of the energy meter according to the aging data, and the energy meter enters the retest process; retesting the energy meter to obtain test data C, and the energy meters that pass the retest are written with the optimal calibration coefficient and then enter the factory test, while the unqualified energy meters enter the aging process after calibration; the energy meter undergoes the factory test to obtain test data, and it is shipped out after passing the factory test. In the whole calibration process of the present invention, the calibration process of the energy meter is analyzed to select the most matching data for calculating the calibration coefficient, and the reliability and certainty are much higher than those of the traditional calibration scheme.

Description

Technical Field

[0001] The present invention relates to a production calibration method for a high-precision AC energy meter, belonging to the technical field of energy meter calibration. Background Art

[0002] Instrument calibration refers to the process of associating the response indication value of an instrument with its start signal or with the true value measured by other methods. Under specified conditions, a set of operations for determining the relationship between the value indicated by a measuring instrument or measuring system, or the value represented by a physical measuring instrument or reference material, and the value reproduced by a standard. Its purpose is to determine the indication value of the measuring device by comparing it with a standard. Currently, when calibrating a high-precision electric energy meter, the successive comparison method is adopted, that is, the voltage, current values at different gears are compared with a standard energy meter, and a suitable proportionality coefficient is set as the calibration value.

[0003] The parameters that need to be calibrated for an AC energy meter include voltage amplitude, current amplitude, voltage phase, and current phase. Each item needs to be calibrated.

[0004] The prior art uses software to read the detection values of a standard meter through communication methods such as the 485 bus, and write them into the energy meter to be calibrated through communication methods such as the 485 bus. After calibration, power on and age, and retest after a specific aging time. If the retest is qualified, it leaves the factory; if it is unqualified, it is returned for repair, recalibrated again, aged again, and retested again until the test is qualified.

[0005] This calibration method has two disadvantages. One is that the calibration is completely random. Neither the timing of calibration is selected, nor the stability of the device hardware is selected, and the deviation of the calibrated value is also random and uncontrollable. The other is that the entire calibration process is isolated. Calibration only focuses on calibration, aging only focuses on aging, and testing only focuses on testing, resulting in low efficiency. Summary of the Invention

[0006] In order to overcome the above problems, the present invention provides a production calibration method for a high-precision AC energy meter. During the entire calibration process, this calibration method analyzes the calibration process of the energy meter to select the most matching data for calculating the calibration coefficient, and its reliability and certainty are much higher than those of traditional calibration schemes.

[0007] The technical solution of the present invention is as follows:

[0008] A production calibration method for a high-precision AC energy meter includes the following steps:

[0009] Calibrate the produced energy meter;

[0010] Test the energy meter to obtain test data A. The qualified energy meters enter the aging process, and the unqualified ones are repaired and then tested again;

[0011] Age the electricity meter, obtain aging data, adjust the aging time of the electricity meter according to the aging data, and the electricity meter enters the retest process;

[0012] Retest the electricity meter, obtain test data C, write the optimal calibration coefficient into the electricity meter that passes the retest and then enter the factory test, and calibrate the electricity meter that fails the retest and then enter the aging process;

[0013] The electricity meter is subjected to a factory test, test data is obtained, and it is shipped out after passing the factory test.

[0014] Furthermore, test data A and test data C include the standard meter detection value and the electricity meter detection value; the standard meter is used to calibrate the electricity meter.

[0015] Furthermore, the acquisition frequencies of the standard meter detection values in test data A and test data C are the same.

[0016] Furthermore, the acquisition frequencies of the electricity meter detection values in test data A and test data C are the same.

[0017] Furthermore, it further includes:

[0018] Sort the standard meter detection values and the electricity meter detection values of test data A by time;

[0019] Calculate the moving window standard deviation of test data A, obtain the window with the moving window standard deviation lower than the threshold T0 and the minimum standard deviation mean value, and calculate the calibration coefficient X0 according to the corresponding test data A within the window;

[0020] Delay the electricity meter detection value of test data A by one sampling period, calculate the moving window standard deviation of test data A, obtain the window with the moving window standard deviation lower than the threshold T and the minimum standard deviation mean value, and calculate the calibration coefficient X1 according to the corresponding test data A within the window;

[0021] Advance the electricity meter detection value of test data A by one sampling period, calculate the moving window standard deviation of test data A, obtain the window with the moving window standard deviation lower than the threshold T and the minimum standard deviation mean value, and calculate the calibration coefficient X2 according to the corresponding test data A within the window;

[0022] Compare the deviations of the calibration coefficients X0, X1, and X2 from the standard meter detection value respectively, and take the calibration coefficient with the smallest deviation as the calibration coefficient X 10 .

[0023] Furthermore, the aging process is carried out on multiple electricity meters simultaneously; it further includes:

[0024] Set the calibration coefficient X 10 Into all electricity meters for aging;

[0025] Obtain the standard deviation of various electricity meter detection values during aging of the electricity meter;

[0026] Judge the stability of each parameter during aging of each electricity meter through the standard deviation. For electricity meters with unqualified stability, extend the aging time, and for qualified electricity meters, age them according to the standard time.

[0027] Furthermore, it also includes:

[0028] Sort the standard meter detection values and electricity meter detection values of test data C by time;

[0029] Calculate the moving window standard deviation of test data C, obtain the window with the moving window standard deviation lower than the threshold T1 and the minimum standard deviation mean, and calculate the calibration coefficient X3 according to the corresponding test data C within the window;

[0030] Delay the electricity meter detection value of test data C by one sampling period, calculate the moving window standard deviation of test data C, obtain the window with the moving window standard deviation lower than the threshold T and the minimum standard deviation mean, and calculate the calibration coefficient X4 according to the corresponding test data C within the window;

[0031] Advance the electricity meter detection value of test data C by one sampling period, calculate the moving window standard deviation of test data C, obtain the window with the moving window standard deviation lower than the threshold T and the minimum standard deviation mean, and calculate the calibration coefficient X5 according to the corresponding test data C within the window;

[0032] Compare the deviations of the calibration coefficients X3, X4, and X5 from the standard meter detection values respectively, and take the calibration coefficient with the smallest deviation as the calibration coefficient X 30 ;

[0033] Detect the calibration coefficient X of the electricity meter 10 , X 30 to see if the amplitude and phase are both qualified. When there are unqualified items in X 10 , retest the electricity meter after recalibration. When there are unqualified items in X 30 , set the calibration coefficient X 30 to X 10 , and re-enter the aging process.

[0034] Furthermore, it also includes:

[0035] Calculate the upper and lower limits of the calibration coefficient X 30 so that X 30 ± ΔX are all within the factory standard;

[0036] Conduct an electricity test on the calibration coefficient X 30 parameter group to obtain the electricity deviation;

[0037] By calibrating the coefficient X 30Perform Kalman filtering on the parameters to obtain the calibration coefficient X 40 ; The calibration coefficient X 40 is within X 30 ±ΔX;

[0038] Set the calibration coefficient X 40 into the electric energy meter.

[0039] Furthermore, the parameters of the Kalman filtering are calculated from the original data collected by X0, X1, X2, and X3.

[0040] Furthermore, the standard meter detection value and the electric energy meter detection value include voltage, current, voltage phase, and current phase.

[0041] The present invention has the following beneficial effects:

[0042] 1. During the entire calibration process, this calibration method analyzes the calibration process of the electric energy meter and selects the most matching data to calculate the calibration coefficient. The traditional calibration scheme is discrete point-to-point calibration. The reliability and certainty of this calibration method are much higher than those of the traditional calibration scheme.

[0043] 2. This calibration method can dynamically calculate the performance of the electric energy meter to be calibrated during the entire calibration cycle and the time and effect of aging required, providing a large amount of effective data for the calibration research and development of the electric energy meter, while the traditional method can only provide a small amount of effective data.

[0044] 3. The calibration value obtained by this calibration method can design the most optimized calibration value for electric energy metering in the same electric energy meter to be calibrated, while the traditional calibration scheme does not have the function of optimizing the calibration coefficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is the flowchart of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0046] The present invention will be described in detail below with reference to the drawings and specific embodiments.

[0047] Refer to Figure 1 , A production calibration method for a high-precision AC electric energy meter, comprising the following steps:

[0048] Calibrate the produced electric energy meter;

[0049] Test the electric energy meter to obtain test data A. The qualified electric energy meters enter the aging process, and the unqualified ones are repaired and then tested again;

[0050] Age the electric energy meter to obtain aging data, adjust the aging time of the electric energy meter according to the aging data, and the electric energy meter enters the retest process;

[0051] Retest the electric energy meter to obtain test data C. The electric energy meter that passes the retest will be written with the optimal calibration coefficient and enter the factory test. The electric energy meter that fails the retest will enter the aging process after calibration.

[0052] The electric energy meter undergoes factory testing, obtains test data, and is shipped out of the factory after passing the factory testing.

[0053] In some embodiments of the present invention, the test data A and the test data C include standard meter detection values ​​and electric energy meter detection values; the standard meter is used to calibrate the electric energy meter. Preferably, the standard meter is a standard electric energy meter with higher accuracy than the produced electric energy meter.

[0054] In some implementation modes of the present invention, the standard meter detection value collection frequency of the test data A and the test data C is the same; the electric energy meter detection value collection frequency of the test data A and the test data C is the same.

[0055] The collection frequency of the standard meter detection value and the collection frequency of the electric energy meter detection value may be different.

[0056] Preferably, the acquisition frequency is set according to the actual communication conditions, the higher the better.

[0057] In some embodiments of the present invention, the standard meter detection value and the electric energy meter detection value include voltage, current, voltage phase and current phase.

[0058] In one embodiment of the present invention, it also includes:

[0059] Sort the standard meter detection values ​​and the electric energy meter detection values ​​of the test data A by time;

[0060] Calculate the sliding window standard deviation of the test data A, obtain the window whose sliding window standard deviation is lower than the threshold T0 and whose standard deviation mean is the smallest, and calculate the calibration coefficient X0 according to the corresponding test data A in the window;

[0061] For example, if there are 10,000 pieces of collected data, data[1] to data

[10000] .

[0062] To calculate the calibration data, 100 consecutive data are required to calculate the standard deviation data table data_STD[1] to data_STD

[9901] of a sliding window of size 100. data_STD[1] represents the standard deviation of data[1] to data

[100] , data_STD[2] represents the standard deviation of data[2] to data

[101] , data_STD[3] represents the standard deviation of data[3] to data

[103] , and so on. data_STD

[9901] represents the standard deviation of data

[9901] to data

[10000] .

[0063] In the data_STD sequence, if data_STD

[100] is the smallest and data_STD

[100] is less than the data_STD threshold (if the smallest data_STD is greater than the threshold, this calibration is invalid due to unstable power supply or interference. After excluding interference or stabilizing the power supply, recalculate), select data

[100] to data

[199] corresponding to data_STD

[100] and calculate the calibration coefficient X0.

[0064] In the embodiments of the present invention, the following method is used to calculate the calibration coefficient:

[0065]

[0066]

[0067] The actual data F = A * X

[0068] The actual data F is the standard version detection value, and A I 、A U are different items of the electric energy meter detection values, and in this embodiment, they are the current value and the voltage value respectively.

[0069] Delay the electric energy meter detection value of the test data A by one sampling period, calculate the sliding window standard deviation of the test data A, obtain the window with the sliding window standard deviation lower than the threshold T and the smallest standard deviation mean value, and calculate the calibration coefficient X1 according to the corresponding test data A within the window;

[0070] For example, write the value of voltage V[n] to V[n + 1], and write V[n + 1] to V[n + 2] and so on. The standard meter data remains unchanged.

[0071] Advance the electric energy meter detection value of the test data A by one sampling period, calculate the sliding window standard deviation of the test data A, obtain the window with the sliding window standard deviation lower than the threshold T and the smallest standard deviation mean value, and calculate the calibration coefficient X2 according to the corresponding test data A within the window;

[0072] For example, write the value of voltage V[n] to V[n - 1], and write V[n + 1] to V[n] and so on. The standard meter data remains unchanged.

[0073] Compare the deviations of the calibration coefficients X0, X1, and X2 from the standard meter detection values respectively, and use the calibration coefficient with the smallest deviation as the calibration coefficient X 10 。

[0074] In some embodiments, the calibration coefficient X 10 can be set into the electric energy meter.

[0075] The time points collected by the standard meter and the calibrated watt-hour meter and the time when the data reaches the analysis software are not necessarily synchronized. The value with the best synchronization is found through three operations: maintaining, delaying, and advancing.

[0076] The threshold T0 and the sliding window are set manually, and the size of the sliding window is set according to the data size.

[0077] In some embodiments of the present invention, the aging process is performed on multiple watt-hour meters simultaneously.

[0078] In some embodiments, multiple calibrated watt-hour meter devices are connected in series and powered on for aging with a single power supply. The number of series connections is calculated according to the load power of the power supply.

[0079] It further includes:

[0080] Set the calibration coefficient X 10 into all watt-hour meters for aging;

[0081] Obtain the standard deviation of various watt-hour meter detection values of the watt-hour meter during aging;

[0082] Judge the stability of each parameter of each watt-hour meter during aging through the standard deviation. For watt-hour meters with unqualified stability, extend the aging time, and for qualified watt-hour meters, age according to the standard time.

[0083] In some embodiments of the present invention, it further includes:

[0084] Sort the standard meter detection values and the watt-hour meter detection values of the test data C in time order;

[0085] Calculate the sliding window standard deviation of the test data C, obtain the window with the sliding window standard deviation lower than the threshold T1 and the minimum standard deviation mean value, and calculate the calibration coefficient X3 according to the corresponding test data C within the window;

[0086] Delay the watt-hour meter detection values of the test data C by one sampling period, calculate the sliding window standard deviation of the test data C, obtain the window with the sliding window standard deviation lower than the threshold T and the minimum standard deviation mean value, and calculate the calibration coefficient X4 according to the corresponding test data C within the window;

[0087] Advance the watt-hour meter detection values of the test data C by one sampling period, calculate the sliding window standard deviation of the test data C, obtain the window with the sliding window standard deviation lower than the threshold T and the minimum standard deviation mean value, and calculate the calibration coefficient X5 according to the corresponding test data C within the window;

[0088] Compare the deviations of the calibration coefficients X3, X4, and X5 from the standard meter detection values respectively, and take the calibration coefficient with the smallest deviation as the calibration coefficient X 30 ;

[0089] Detect the calibration coefficient X of the watt-hour meter10 and whether the amplitude and phase of X 30 are both qualified. When there are unqualified items, the electricity meter is recalibrated and then tested. 10 When there are unqualified items, the calibration coefficient X 30 is set to X 30 and the aging process is restarted. 10

[0090] In the embodiments of the present invention, if the deviation between the calculated value and the value of the standard meter is less than the preset value, it is considered qualified.

[0091] In a specific embodiment, the calibration coefficient X 30 is set into the electricity meter.

[0092] In some embodiments of the present invention, it further includes:

[0093] Calculating the upper and lower limits of the calibration coefficient X 30 such that both X 30 ±ΔX are within the factory standard;

[0094] Performing an electricity test on the calibration coefficient X 30 parameter group to obtain an electricity deviation;

[0095] By performing Kalman filtering on the parameters of the calibration coefficient X 30 , the calibration coefficient X 40 is obtained; the calibration coefficient X 40 is within X 30 ±ΔX;

[0096] Setting the calibration coefficient X 40 into the electricity meter.

[0097] The standard electricity deviation determined by the electricity meter, so the electricity deviation is minimized on the basis of individual qualification calculated from the two sets of qualified coefficients before and after.

[0098] Preferably, the parameters of the Kalman filtering are calculated from the original data collected by X0, X1, X2, X3.

[0099] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structures made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are similarly included in the patent protection scope of the present invention.​

Claims

1. A production calibration method for a high-precision AC energy meter, characterized in that, It includes the following steps: Calibrate the produced electricity meters; Test the electricity meters to obtain test data A. The qualified electricity meters enter the aging process, and the unqualified ones are repaired and then tested again; Age the electricity meters to obtain aging data, adjust the aging time of the electricity meters according to the aging data, and the electricity meters enter the retest process; Retest the electricity meters to obtain test data C. The qualified electricity meters after retest are written with the optimal calibration coefficient and then enter the factory test, and the unqualified electricity meters are calibrated and then enter the aging process; The electricity meters are subjected to the factory test to obtain test data. After passing the factory test, they leave the factory; Test data A and test data C include the standard meter detection values and the electricity meter detection values; The standard meter is used to calibrate the electricity meters; It also includes: Sort the standard meter detection values and the electricity meter detection values of test data A by time; Calculate the moving window standard deviation of test data A, obtain the window with the moving window standard deviation lower than the threshold T0 and the minimum standard deviation mean value, and calculate the calibration coefficient X0 according to the corresponding test data A within the window; Delay the electricity meter detection value of test data A by one sampling period, calculate the moving window standard deviation of test data A, obtain the window with the moving window standard deviation lower than the threshold T and the minimum standard deviation mean value, and calculate the calibration coefficient X1 according to the corresponding test data A within the window; Advance the electricity meter detection value of test data A by one sampling period, calculate the moving window standard deviation of test data A, obtain the window with the moving window standard deviation lower than the threshold T and the minimum standard deviation mean value, and calculate the calibration coefficient X2 according to the corresponding test data A within the window; Compare the deviations of the calibration coefficients X0, X1, and X2 from the measured values of the standard meter respectively, and use the calibration coefficient with the smallest deviation as the calibration coefficient X 10 ; It also includes: Sort the standard meter detection values and the electricity meter detection values of test data C by time; Calculate the moving window standard deviation of test data C, obtain the window with the moving window standard deviation lower than the threshold T1 and the minimum standard deviation mean value, and calculate the calibration coefficient X3 according to the corresponding test data C within the window; Delay the electricity meter detection value of test data C by one sampling period, calculate the moving window standard deviation of test data C, obtain the window with the moving window standard deviation lower than the threshold T and the minimum standard deviation mean value, and calculate the calibration coefficient X4 according to the corresponding test data C within the window; Advance the electricity meter detection value of test data C by one sampling period, calculate the moving window standard deviation of test data C, obtain the window with the moving window standard deviation lower than the threshold T and the minimum standard deviation mean value, and calculate the calibration coefficient X5 according to the corresponding test data C within the window; Compare the deviations of the calibration coefficients X3, X4, and X5 from the measured values of the standard meter respectively, and use the calibration coefficient with the smallest deviation as the calibration coefficient X 30 ; Detect the calibration coefficient X of the electricity meter 10 and X 30 to check whether both the amplitude and phase are qualified. When there are unqualified items 10 retest the electricity meter after recalibration. When there are unqualified items 30 set the calibration coefficient X 30 to X 10 and re-enter the aging process.

2. The production calibration method of the high-precision AC energy meter according to claim 1, characterized in that, The acquisition frequencies of the standard meter detection values of test data A and test data C are the same.

3. The production and calibration method of the high-precision AC energy meter according to claim 1, characterized in that, The acquisition frequencies of the electricity meter detection values of test data A and test data C are the same.

4. The production calibration method of the high-precision AC energy meter according to claim 3, characterized in that The aging process is carried out on multiple electricity meters simultaneously; it also includes: Set the calibration coefficient X 10 in all watt-hour meters for aging; Obtain the standard deviation of various electricity meter detection values of the electricity meters during aging; Judge the stability of each parameter of each electricity meter during aging through the standard deviation. The electricity meters with unqualified stability have their aging time extended, and the qualified electricity meters are aged according to the standard time.

5. The production and calibration method of the high-precision AC energy meter according to claim 4, characterized in that, It also includes: Calculate the upper and lower limits of the calibration coefficient X 30 such that X 30 ±ΔX is within the factory standard; For the calibration coefficient X 30 Perform an electrical energy test on the parameter group to obtain the electrical energy deviation; By performing Kalman filtering on the parameters of the calibration coefficient X 30 , the calibration coefficient X 40 is obtained; the calibration coefficient X 40 is within X 30 ± ΔX; Set the calibration coefficient X 40 into the electricity meter.

6. The production calibration method of the high-precision AC energy meter according to claim 5, characterized in that, The parameters of the Kalman filter are calculated through the original data collected by X0, X1, and X2.

7. The production calibration method of the high-precision AC energy meter according to claim 1, characterized in that The standard meter detection values and the electricity meter detection values include voltage, current, voltage phase, and current phase.

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