Compression transmission method for harmonic data of three-phase electric energy meter

Abstract

The invention belongs to the technical field of power data processing, and provides a three-phase electric energy meter harmonic data compression transmission method, which comprises the following steps of: screening electric energy meter harmonic waves when the three-phase electric energy meter harmonic data is compressed by discrete Fourier transform and quantization coding; analyzing the relevance between the quantization step size and the amplitude error of the harmonic wave of the electric energy meter, judging whether a target quantization step size which can meet the high compression ratio and the amplitude error at the same time can be found under the limitation of the high compression ratio or not under the linear relevance condition, and if yes, changing the set quantization step size; if not, quantitative step size analysis is carried out on the screened electric energy meter harmonic waves, whether the amplitude error source of the electric energy meter harmonic waves is that the quantitative step size is not matched or not is determined, and if yes, local refined quantization is carried out on the key electric energy meter harmonic waves, and compression ratio balance verification is carried out after quantization; and if verification fails, the compression ratio and the amplitude error are ensured to reach the standard through combined operation of non-key harmonic redundancy cutting and key harmonic efficient coding.

Description

Technical Field

[0001] This invention belongs to the field of power data processing technology, specifically a method for compressing and transmitting harmonic data from a three-phase electricity meter. Background Technology

[0002] In the operation of three-phase electricity meters, harmonic data serves as a key basis for assessing power grid quality. Effective compression is crucial for efficient transmission and storage, and "Discrete Fourier Transform (DFT) + quantization encoding" is currently the mainstream compression technology. However, traditional compression schemes have significant shortcomings: Firstly, fixed quantization step sizes struggle to balance compression ratio and data accuracy. Excessively large step sizes can lead to amplitude errors in critical harmonics affecting power grid quality, such as the 3rd and 5th harmonics, exceeding the requirement of "harmonic measurement error ≤ 2%" in the GB / T17215.323-2022 standard. Conversely, excessively small step sizes result in low compression efficiency and increased storage and transmission costs. Secondly, the lack of systematic analysis of the correlation between quantization step size and amplitude error prevents dynamic parameter adjustment to balance the relationship. Furthermore, the failure to differentiate between critical and non-critical harmonic characteristics makes it difficult to accurately pinpoint the source of error (e.g., whether it's due to quantization step size mismatch) when the compression ratio is substandard. Additionally, the lack of differentiated optimization strategies for different harmonics results in insufficient adaptability and robustness of the scheme. Furthermore, when traditional solutions conflict with compression ratio and accuracy, they often lack supplementary methods such as redundant data trimming and efficient encoding, making it impossible to ensure that both standards are met simultaneously. This makes it difficult to meet the refined and efficient requirements for harmonic data compression in complex power grid scenarios. Therefore, a progressive and differentiated optimization solution is urgently needed to address these issues.

[0003] Therefore, the present invention provides a method for compressing and transmitting harmonic data of a three-phase energy meter. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0005] The technical solution adopted by this invention to solve its technical problem is: a method for compressing and transmitting harmonic data of a three-phase energy meter, comprising the following steps: Step 1: When compressing the harmonic data of three-phase electricity meters using Discrete Fourier Transform + Quantization encoding, compare the amplitude error of the harmonics of the electricity meters under the set quantization step size to screen the harmonics of the electricity meters. Step 2: Analyze the correlation between the quantization step size and the amplitude error of the energy meter harmonics. If there is a linear correlation, determine whether a target quantization step size can be found that simultaneously satisfies both the high compression ratio and the amplitude error under the constraint of high compression ratio. If so, modify the set quantization step size according to the target quantization step size. Step 3: If not, perform quantization step size analysis on the screened electricity meter harmonics to determine whether the source of the amplitude error of the electricity meter harmonics is quantization step size mismatch. If so, perform local fine quantization on the key electricity meter harmonics and perform compression ratio balance verification after local fine quantization. Step 4: If the compression ratio balance verification fails, then the compression ratio and amplitude error are ensured to meet the standards by combining non-critical harmonic redundancy trimming with critical harmonic efficient coding.

[0006] A further technical solution of the present invention is as follows: the process of screening harmonics in an electricity meter is as follows: Based on any harmonic of the electricity meter, obtain the amplitude error of the harmonic of the electricity meter; If the amplitude error is greater than the amplitude error threshold, then the harmonics of the electricity meter corresponding to the amplitude error are selected.

[0007] A further technical solution of the present invention is as follows: the process of analyzing the correlation between the quantization step size and the amplitude error of the harmonics of the electricity meter is as follows: Based on any harmonic of the electricity meter, the amplitude error of the harmonic of the electricity meter under different historical quantization step sizes is obtained, and the amplitude error sequence is integrated to obtain the amplitude error sequence. The different historical quantization step sizes are integrated into the quantization step size sequence. Calculate the Pearson correlation coefficient between the amplitude error sequence and the quantization step size sequence, and obtain the correlation coefficient after absolute value conversion; If the correlation coefficient is greater than or equal to the correlation coefficient threshold, it indicates that there is a linear correlation between the quantization step size and the amplitude error of the harmonics of the electricity meter. If the amplitude error of all electricity meter harmonics is linearly correlated with the quantization step size, then it indicates that there is a linear correlation.

[0008] A further technical solution of the present invention is as follows: the process of determining whether a target quantization step size that can simultaneously satisfy both high compression ratio and amplitude error can be found under the constraint of high compression ratio is as follows: A high compression ratio is obtained, and the required quantization step size of each energy meter's harmonics is calculated by combining the maximum amplitude of each energy meter's harmonics. The maximum quantization step size among the required quantization step sizes for harmonics of each energy meter is selected as the minimum endpoint value, and the set quantization step size is used as the maximum endpoint value to construct the quantization step size range. Based on any harmonic of the electricity meter, the error of the electricity meter harmonic is obtained to satisfy the quantization step size; If the errors of all energy meter harmonics are within the range of the quantization step size, it means that a target quantization step size that can simultaneously satisfy both high compression ratio and amplitude error can be found under the constraint of high compression ratio. Conversely, it means that a target quantization step size that can simultaneously satisfy both high compression ratio and amplitude error cannot be found under the constraint of high compression ratio. If a target quantization step size that can simultaneously satisfy both high compression ratio and amplitude error can be found, then the quantization step size that satisfies the minimum error is selected as the target quantization step size, and the previously set quantization step size is changed to the target quantization step size.

[0009] A further technical solution of the present invention is as follows: the method for obtaining the quantization step size of the harmonic error of the electricity meter is as follows: Based on any harmonic of the electricity meter, according to the amplitude error sequence and the quantization step sequence, and by fitting with the least squares method, a fitting model for amplitude error-quantization step is obtained. Substituting the amplitude error of the electricity meter harmonics into the fitting model of amplitude error-quantization step size, we find that the harmonic error of the electricity meter satisfies the quantization step size.

[0010] A further technical solution of the present invention is as follows: The process of performing quantization step size analysis on the screened harmonics of the electricity meter to determine whether the amplitude error of the electricity meter harmonics is due to quantization step size mismatch is as follows: Based on any harmonic of the electricity meter, by setting several different test quantization step sizes, the first error sequence and the second error sequence are obtained; Calculate the Euclidean distance between the first error sequence and the second error sequence. If the Euclidean distance meets the requirements, it indicates that the source of the harmonic amplitude error of the electricity meter is the quantization step size mismatch; otherwise, it is not.

[0011] A further technical solution of the present invention is as follows: the first error sequence and the second error sequence are obtained in the following way: Set several different test quantization step sizes, obtain the amplitude error of the harmonic data of the energy meter under different test quantization step sizes, and integrate them to obtain the first error sequence; By substituting different test quantization step sizes into the amplitude error-quantization step size fitting model, the amplitude error corresponding to different test quantization step sizes is obtained, and then integrated to obtain the second error sequence.

[0012] A further technical solution of the present invention is as follows: the process of performing local fine quantization of harmonics in key energy meters is as follows: Based on the priority of the impact on power grid quality, the key energy meter harmonics are identified in the energy meter harmonics. Based on any key energy meter harmonic, calculate the fine quantization step size of the key energy meter harmonic according to the original harmonic amplitude and harmonic measurement error; for the key energy meter harmonic, change the set quantization step size of the key energy meter harmonic according to the fine quantization step size.

[0013] A further technical solution of the present invention is as follows: the process of performing compression ratio balance verification after local fine quantization is as follows: The amount of harmonic data from the electricity meter before and after Yaso is obtained and the ratio is calculated to obtain the compression ratio. If the compression ratio is higher than or equal to the set high compression ratio, the compression ratio balance verification is successful; otherwise, the compression ratio balance verification fails.

[0014] A further technical solution of the present invention is as follows: the process of ensuring that both the compression ratio and amplitude error meet the standards through the combination of non-critical harmonic redundancy trimming and critical harmonic efficient coding is as follows: Only the amplitude information of harmonics from non-critical energy meters is retained, while phase data is deleted to reduce the amount of harmonic data from non-critical energy meters. Taking advantage of the small fluctuation of harmonic amplitude in critical energy meters over a short period of time, the complete amplitude is stored in the first frame, and subsequent frames only store the amplitude difference with the previous frame, thus reducing the amount of harmonic data from critical energy meters. The quantization coefficients are normalized according to the maximum amplitude of the harmonics from critical energy meters to reduce the number of bits in the encoding and ensure that the total error after normalization is ≤2%.

[0015] The beneficial effects of this invention are as follows: First, harmonics with excessive amplitude errors are screened based on a set quantization step size, ensuring that the initial error of the core harmonics meets the standard; then, the linear correlation between the quantization step size and amplitude error is analyzed, and a target quantization step size that balances both is found and adjusted under the constraint of high compression ratio; if the target step size does not exist, the source of error is verified by testing to see if it is due to quantization step size mismatch, and local fine quantization is performed on the key harmonics to verify the compression ratio balance; if the compression ratio still does not meet the standard, redundant data of non-key harmonics is trimmed and the encoding of key harmonics is optimized to ensure that both standards are met. In terms of overall technical effect, it ensures that the amplitude error of key harmonics meets the requirements of GB / T17215.323-2022 (≤2%) through error screening, local fine quantization, and standard constraints, guaranteeing the accuracy of core data, and maximizes the compression ratio through dynamic adjustment of quantization step size, correlation analysis, and encoding optimization. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 This is a flowchart of the steps of a method for compressing and transmitting harmonic data of a three-phase energy meter according to the present invention; Figure 2 This is a logic judgment diagram of a method for compressing and transmitting harmonic data of a three-phase energy meter as described in this invention. Detailed Implementation

[0018] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0019] Please see Figure 1 As shown in the embodiment of the present invention, a method for compressing and transmitting harmonic data of a three-phase energy meter includes the following steps: Step 1: When compressing the harmonic data of three-phase electricity meters using Discrete Fourier Transform + Quantization encoding, compare the amplitude error of the harmonics of the electricity meters under the set quantization step size to screen the harmonics of the electricity meters. In step one, the pre-set quantization step size is set in advance by technicians when compressing the harmonic data of the three-phase energy meter through "discrete Fourier transform + quantization encoding"; In step one, the process of screening harmonics in the electricity meter is as follows: Based on any harmonic of the electricity meter, obtain the amplitude error of the harmonic and compare it with the amplitude error threshold. If the amplitude error is less than or equal to the amplitude error threshold, no operation is performed; If the amplitude error is greater than the amplitude error threshold, the harmonics of the electricity meter corresponding to the amplitude error are selected, and the selection is completed. In step one, the method for obtaining the amplitude error of the harmonics of the electricity meter is as follows: Acquire the raw signal (current / voltage signal) of a three-phase energy meter through high-precision AD sampling (such as 16-bit or 24-bit sampling), perform DFT calculation on the raw signal (e.g., calculate the amplitude of each harmonic such as the 3rd, 5th, and 7th harmonics with a fundamental frequency of 50Hz), and obtain the raw harmonic amplitude A. 原始 ; The original harmonic amplitude is quantized using a pre-defined quantization step size to obtain the quantized harmonic amplitude. The error A between the original harmonic amplitude and the quantized harmonic amplitude is then calculated. 量化 The amplitude error is obtained, and the specific calculation formula is as follows: ; It should be noted that the amplitude error threshold of 5% is set according to the requirement of "harmonic measurement error ≤ 2%" in GB / T17215.323-2022 "Special Requirements for AC Measuring Equipment Part 23: Static Active Energy Meters (0.2S and 0.5S Class)". It can be understood that if the quantization step size is too large, the amplitude error of the 3rd and 5th harmonics (the main harmonics affecting power grid quality) will exceed 5%, which does not meet the requirement of "harmonic measurement error ≤ 2%" in GB / T17215.323-2022 "Special Requirements for AC Measuring Equipment Part 23: Static Active Energy Meters (0.2S and 0.5S Class)". Understandably, the purpose of step one is to: calculate and compare the amplitude error of each harmonic with the threshold by setting the quantization step size, and screen out harmonics with excessive errors. Its function is to initially ensure that the amplitude error of key harmonics (such as the 3rd and 5th harmonics) in the harmonic data compressed by "Discrete Fourier Transform + Quantization Encoding" meets the requirements of GB / T17215.323-2022 standard, providing basic screening results for subsequent compression optimization and ensuring the accuracy of core harmonic data. Step 2: Analyze the correlation between the quantization step size and the amplitude error of the energy meter harmonics. If there is a linear correlation, determine whether a target quantization step size can be found that simultaneously satisfies both the high compression ratio and the amplitude error under the constraint of high compression ratio. If so, modify the set quantization step size according to the target quantization step size. In step two, the process of analyzing the correlation between the quantization step size and the amplitude error of the electricity meter harmonics is as follows: Based on any harmonic of the electricity meter, the amplitude error of the harmonic of the electricity meter under different historical quantization step sizes is obtained, and the amplitude error sequence is integrated to obtain the amplitude error sequence. The different historical quantization step sizes are integrated into the quantization step size sequence. It should be noted that the amplitude error sequence is obtained by integrating the amplitude errors of harmonics from different energy meters at different quantization step sizes during historical compressed transmission processes. Calculate the Pearson correlation coefficient between the amplitude error sequence and the quantization step size sequence, and obtain the correlation coefficient after absolute value conversion; If the correlation coefficient is greater than or equal to the correlation coefficient threshold, it indicates that there is a linear correlation between the quantization step size and the amplitude error of the harmonics of the electricity meter. If the correlation coefficient is less than the correlation coefficient threshold, it means that there is no linear correlation between the quantization step size and the amplitude error of the harmonics of the electricity meter. If the amplitude error of all energy meter harmonics is linearly correlated with the quantization step size, then it indicates that there is a linear correlation. If the amplitude error of all energy meter harmonics has no linear correlation with the quantization step size or has a non-linear correlation, then it means that there is no linear correlation. In step two, the process of determining whether a target quantization step size that simultaneously satisfies both the high compression ratio and amplitude error can be found under the constraint of a high compression ratio is as follows: To obtain a high compression ratio, and based on the maximum amplitude of the harmonics of each energy meter, the required quantization step size for the harmonics of each energy meter is calculated. The specific calculation is as follows: ; Where CR represents the high compression ratio, and Amax represents the maximum amplitude of harmonics in each electricity meter. Quantize the required harmonic step size for each electricity meter; For example, consider the third harmonic (Amax = 20A): when At 0.5A, the compression ratio CR = 32 / 6 = 5.3:1; when At 1A, the compression ratio CR = 32 / 5 = 6.4:1; when When the pressure is 2A, the compression ratio CR = 32 / 4 = 8:1; when At 4A, the compression ratio CR = 32 / 3 = 10.7:1; The maximum quantization step size among the required quantization step sizes for harmonics of each energy meter is selected as the minimum endpoint value, and the set quantization step size is used as the maximum endpoint value to construct the quantization step size range. It should be noted that there is a positive relationship between the quantization step size and the compression ratio. Therefore, the maximum quantization step size among the required quantization step sizes is selected as the minimum endpoint value. The purpose is to find a quantization step size within the limit of the high compression ratio that can meet the amplitude error requirements of the harmonics of each energy meter. The maximum quantization step size among the required quantization step sizes is required to be less than the set quantization step size. Based on any harmonic of the electricity meter, according to the amplitude error sequence and the quantization step sequence, and by fitting with the least squares method, a fitting model for amplitude error-quantization step is obtained. It should be noted that the above amplitude error is linearly related to the quantization step size. Therefore, the least squares method is used for fitting. It should also be noted that each energy meter harmonic has a fitting model of amplitude error-quantization step size. Based on any harmonic of the electricity meter, the amplitude error of the harmonic of the electricity meter is substituted into the fitting model of amplitude error-quantization step size, and the error of the harmonic of the electricity meter satisfies the quantization step size. The harmonic errors of each energy meter are compared with the quantization step size and the quantization step size range. If the errors of all energy meter harmonics satisfy that the quantization step size is within the quantization step size range, it means that under the constraint of high compression ratio, a target quantization step size that can simultaneously satisfy high compression ratio and amplitude error can be found. If a target quantization step size that can simultaneously satisfy both high compression ratio and amplitude error can be found, then the quantization step size that satisfies the minimum error is selected as the target quantization step size, and the set quantization step size is changed to the target quantization step size. If the errors of all energy meter harmonics satisfy that the quantization step size is not within the quantization step size range or is not uniformly within the quantization step size range, it means that under the constraint of high compression ratio, it is impossible to find a target quantization step size that can simultaneously satisfy high compression ratio and amplitude error. It is understandable that the error satisfies the quantization step size, which represents the quantization step size that the energy meter harmonic data compression needs to meet the amplitude error requirement. The quantization step size range is constructed based on the requirement of high compression ratio. If the error of all energy meter harmonics satisfies the quantization step size and is within the quantization step size range, it means that a quantization step size that can satisfy both amplitude error and high compression ratio can be found. Understandably, the purpose of step two is to: analyze the linear relationship between quantization step size and amplitude error, combine the high compression ratio to construct the quantization step size range, use the fitting model to find the target quantization step size and adjust the set value. Its purpose is to maximize the data compression ratio while ensuring that the amplitude error meets the standard, and achieve a balance between compression efficiency and data accuracy. Step 3: If not, perform quantization step size analysis on the screened electricity meter harmonics to determine whether the source of the amplitude error of the electricity meter harmonics is quantization step size mismatch. If so, perform local fine quantization on the key electricity meter harmonics and perform compression ratio balance verification after local fine quantization. In step three, the process of performing quantization step size analysis on the screened electricity meter harmonics to determine whether the amplitude error of the electricity meter harmonics is caused by quantization step size mismatch is as follows: Based on any harmonic of an energy meter, several different test quantization step sizes are set (such as 1 / 2, 1 / 3, etc. of the pre-set quantization step size), the amplitude error of the energy meter harmonic data under different test quantization step sizes is obtained, and the data are integrated to obtain the first error sequence. Substituting different test quantization step sizes into the amplitude error-quantization step size fitting model, the amplitude error corresponding to different test quantization step sizes is obtained, and then integrated to obtain the second error sequence; It is understandable that by substituting different test quantization step sizes into the fitting model of amplitude error - quantization step size, the amplitude error contained in the first error sequence is the theoretical amplitude error corresponding to different quantization step sizes (when the amplitude error originates from quantization step size mismatch). The amplitude error of the energy meter harmonics obtained under different test quantization step sizes is the actual amplitude error. The deviation between the actual amplitude error and the theoretical amplitude error can reflect whether the source of the amplitude error of the energy meter harmonics is quantization step size mismatch. Calculate the Euclidean distance between the first error sequence and the second error sequence, and compare it with the Euclidean distance threshold; If the Euclidean distance is greater than the Euclidean distance threshold, it means that the source of the amplitude error of the harmonics of the electricity meter is not the quantization step size mismatch. Then other sources of amplitude error should be analyzed, including but not limited to phase deviation. If the Euclidean distance is less than or equal to the Euclidean distance threshold, it indicates that the source of the harmonic amplitude error of the electricity meter is quantization step size mismatch. In step three, the process of local fine-grained quantization of the harmonics of the key energy meters is as follows: Based on the priority of the impact on power grid quality (such as the key requirements for harmonic monitoring in GB / T17215.323-2022), the key harmonics of electricity meters are identified in the harmonics of electricity meters; Based on any key energy meter harmonic, according to the original harmonic amplitude A of the key energy meter harmonic... 原始In addition to the harmonic measurement error (2%), the fine-grained quantization step size for calculating the harmonics of key energy meters is calculated. 精细 The specific calculation formula is as follows: ; ; For harmonics in critical energy meters, based on refined quantization step size 精细 Change the quantization step size that has been set for harmonics in key energy meters; In step three, the process of performing compression ratio balancing verification after local fine quantization is as follows: The amount of harmonic data from the electricity meter before and after Yaso is obtained and the ratio is calculated to obtain the compression ratio. For example, the compression ratio is calculated as follows: Assuming a scenario where the total harmonics are 10 (2 critical energy meter harmonics + 8 non-critical energy meter harmonics (determined by the priority of grid quality impact)), the raw data is 4 bytes / harmonic (floating-point), and after quantization, it is encoded in binary (the number of bits is determined by the step size): Harmonics of critical energy meters (2nd order): 6 bits / order are required when the original step size Δ=0.5A, and 7 bits / order are required when Δ=0.4A after refinement (due to the increase in quantization level), for a total of 2 x 7 = 14 bits; Harmonics of non-critical energy meters (8th order): 6 bits / order when the step size Δ=0.5A, for a total of 8 x 6 = 48 bits; The total data size after compression is (14+48):8 = 62:8 = 7.75 bytes (1 byte = 8 bits). Original total data size = 10 times x 4 bytes = 40 bytes, compression ratio = 40:7.75 x = 5.16:1; If the compression ratio is higher than or equal to the set high compression ratio, it means that the compression ratio balance verification is successful and no operation is required. If the compression ratio is lower than the set high compression ratio, it means that the compression ratio balance verification has failed. Understandably, the purpose of step three is to: analyze the source of error by testing the quantization step size when a target quantization step size that meets the requirements cannot be found, perform local fine quantization of the key harmonics and verify the compression ratio balance. Its purpose is to solve the error problem caused by the mismatch of quantization step size. While ensuring the measurement accuracy of the key harmonics, it attempts to maintain a high compression ratio through local adjustments to avoid the overall compression effect from deteriorating. Step 4: If the compression ratio balance verification fails, then the compression ratio and amplitude error are ensured to meet the standards by combining non-critical harmonic redundancy trimming with critical harmonic efficient coding. In step four, the process of ensuring that both the compression ratio and amplitude error meet the standards through the combination of non-critical harmonic redundancy trimming and critical harmonic efficient coding is as follows: Only the amplitude information of harmonics (such as the 7th order and above) of non-critical energy meters is retained, and phase data is deleted (phase has a very small impact on power grid quality assessment), reducing the amount of harmonic data of non-critical energy meters by about 50%. Taking advantage of the small fluctuation of harmonic amplitude in a short period of time of critical energy meters, the first frame stores the complete amplitude, and subsequent frames only store the amplitude difference with the previous frame, reducing the amount of harmonic data of critical energy meters. The quantization coefficient is normalized according to the maximum amplitude of the harmonics of critical energy meters, reducing the number of bits in the encoding, and ensuring that the total error after normalization is ≤2%. For example, non-critical harmonic redundancy reduction: for the 7th, 9th, and 11th harmonics, only amplitude information (2 bytes) is retained, and phase data (2 bytes) is deleted. The data size of a single non-critical harmonic group is reduced from 4 bytes / harmonic to 2 bytes / harmonic, and the total data size of the 3rd non-critical harmonic is reduced by 50% (from 12 bytes to 6 bytes). The first frame of the 3rd harmonic stores the complete amplitude (20A), and subsequent frames only store the difference from the previous frame (e.g., fluctuation range ±1A, which can be represented by 1 byte). The same applies to the 5th harmonic, where the first frame stores 15A, and subsequent frames store the difference. (±0.8A, 1 byte representation), reducing data volume by 50% compared to the original 4 bytes / harmonic; normalization of quantization coefficients for key harmonics: for the 3rd harmonic, with the maximum amplitude of 20A as the baseline, the number of bits in the encoding is increased from 6 bits (step size 0.5A) to 5 bits (step size 0.625A) after normalization, with an error of <1.5% (≤2%); for the 5th harmonic, with 15A as the baseline, the number of bits in the encoding is reduced from 5 bits (step size 0.5A) to 4 bits (step size 0.9375A) after normalization, with an error of ≤1.25% (≤2%). It is understandable that the purpose of step four is to combine non-critical harmonic redundancy pruning with critical harmonic efficient coding when the compression ratio balance verification fails. Its purpose is to reduce the amount of non-critical data and optimize the coding method of critical data, thereby effectively improving the overall compression ratio while ensuring that the amplitude error meets the standard. Ultimately, it achieves the dual standard of compression ratio and amplitude error, ensuring the effectiveness and reliability of harmonic data compression transmission. The technical solution and advantages of this application are as follows: First, based on a set quantization step size, harmonics with excessive amplitude errors are screened out to ensure that the initial error of the core harmonics meets the standard; then, the linear correlation between the quantization step size and the amplitude error is analyzed, and a target quantization step size that balances both is found and adjusted under the constraint of high compression ratio; if the target step size does not exist, the source of error is verified by testing to see if it is a quantization step size mismatch, and local fine quantization is performed on the key harmonics to verify the compression ratio balance; if the compression ratio still does not meet the standard, redundant data of non-key harmonics is trimmed and the key harmonic coding is optimized to ensure that both standards are met. In terms of overall technical effect, the key harmonic amplitude error meets the requirements of GB / T17215.323-2022 (≤2%) through error screening, local fine quantization, and standard constraints, ensuring the accuracy of core data, and the compression ratio is maximized through dynamic adjustment of the quantization step size, correlation analysis, and coding optimization.

[0020] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for compressed transmission of harmonic data of a three-phase electric energy meter, characterized in that: The method comprises the following steps: Step 1: When the discrete Fourier transform + quantization coding compression three-phase electric energy meter harmonic data is performed, the amplitude error of the electric energy meter harmonic under the set quantization step is compared, and the electric energy meter harmonic is screened; Step 2: The correlation between the quantization step and the amplitude error of the electric energy meter harmonic is analyzed, and in the case of linear correlation, it is judged whether the target quantization step that can simultaneously satisfy the high compression ratio and the amplitude error can be found under the limitation of the high compression ratio, if yes, the set quantization step is changed according to the target quantization step; Step 3: If not, the quantization step analysis is performed on the screened electric energy meter harmonic, and it is determined whether the source of the amplitude error of the electric energy meter harmonic is the mismatch of the quantization step, if yes, the local fine quantization is performed on the key electric energy meter harmonic, and the compression ratio balance verification is performed after the local fine quantization; Step 4: If the compression ratio balance verification result fails, the non-key harmonic redundancy pruning + key harmonic efficient coding combined operation is performed to ensure that the compression ratio and the amplitude error both meet the standards.

2. The three-phase electric energy meter harmonic data compression transmission method according to claim 1, characterized in that: the process of screening the electric energy meter harmonic is: based on any electric energy meter harmonic, the amplitude error of the electric energy meter harmonic is obtained; if the amplitude error is greater than the amplitude error threshold, the electric energy meter harmonic corresponding to the amplitude error is screened out.

3. The three-phase electric energy meter harmonic data compression transmission method according to claim 2, characterized in that: the process of analyzing the correlation between the quantization step and the amplitude error of the electric energy meter harmonic is: based on any electric energy meter harmonic, the amplitude error of the electric energy meter harmonic under different historical quantization steps is obtained, and the amplitude error sequence is integrated to integrate the different historical quantization steps into the quantization step sequence; the Pearson correlation coefficient between the amplitude error sequence and the quantization step sequence is calculated, and the correlation coefficient is obtained after being absolute valued; if the correlation coefficient is greater than or equal to the correlation coefficient threshold, it indicates that there is a linear correlation between the quantization step and the amplitude error of the electric energy meter harmonic; if the amplitude error of all electric energy meter harmonics is linearly correlated with the quantization step, it indicates that there is a linear correlation.

4. The three-phase electric energy meter harmonic data compression transmission method according to claim 3, characterized in that: the process of judging whether the target quantization step that can simultaneously satisfy the high compression ratio and the amplitude error can be found under the limitation of the high compression ratio is: the high compression ratio is obtained, and the required quantization step of each electric energy meter harmonic is calculated in combination with the maximum amplitude of each electric energy meter harmonic; the maximum quantization step in the required quantization step of each electric energy meter harmonic is selected as the minimum endpoint value, the set quantization step is selected as the maximum endpoint value, and the quantization step range is constructed; based on any electric energy meter harmonic, the error of the electric energy meter harmonic is obtained to satisfy the quantization step; if the error satisfying quantization steps of all electric energy meter harmonics are within the quantization step range, it indicates that the target quantization step that can simultaneously satisfy the high compression ratio and the amplitude error can be found under the limitation of the high compression ratio, otherwise, it indicates that the target quantization step that can simultaneously satisfy the high compression ratio and the amplitude error cannot be found under the limitation of the high compression ratio. If the target quantization step size that can simultaneously satisfy the high compression ratio and the amplitude error can be found, the minimum error satisfying quantization step size is selected as the target quantization step size, and the set quantization step size is changed to the target quantization step size.

5. The compression transmission method of three-phase electric energy meter harmonic data according to claim 4, characterized in that: The acquisition method of the error satisfying quantization step size of the electric energy meter harmonic is: Based on any electric energy meter harmonic, the least square method is used for fitting according to the amplitude error sequence and the quantization step size sequence, and a fitting model about the amplitude error-quantization step size is obtained; The amplitude error of the electric energy meter harmonic is substituted into the fitting model of the amplitude error-quantization step size, and the error satisfying quantization step size of the electric energy meter harmonic is obtained.

6. The compression transmission method of three-phase electric energy meter harmonic data according to claim 5, characterized in that: The process of determining whether the amplitude error source of the electric energy meter harmonic is the mismatch of the quantization step size is: Based on any electric energy meter harmonic, a first error sequence and a second error sequence are obtained by setting different test quantization step sizes; The Euclidean distance between the first error sequence and the second error sequence is calculated, and if the Euclidean distance meets the requirements, it indicates that the amplitude error source of the electric energy meter harmonic is the mismatch of the quantization step size, otherwise, it is not.

7. The compression transmission method of three-phase electric energy meter harmonic data according to claim 6, characterized in that: The acquisition method of the first error sequence and the second error sequence is: Different test quantization step sizes are set, the amplitude error of the electric energy meter harmonic data under different test quantization step sizes is obtained, and the first error sequence is integrated; Different test quantization step sizes are substituted into the fitting model of the amplitude error-quantization step size, the amplitude error corresponding to different test quantization step sizes is obtained, and the second error sequence is integrated.

8. The compression transmission method of three-phase electric energy meter harmonic data according to claim 7, characterized in that: The process of local fine quantization of the key electric energy meter harmonic is: The key electric energy meter harmonic is determined in the electric energy meter harmonic according to the grid quality influence priority; Based on any key electric energy meter harmonic, the fine quantization step size of the key electric energy meter harmonic is calculated according to the obtained original harmonic amplitude and harmonic measurement error of the key electric energy meter harmonic, and the set quantization step size of the key electric energy meter harmonic is changed according to the fine quantization step size.

9. The compression transmission method of three-phase electric energy meter harmonic data according to claim 8, characterized in that: The process of compression ratio balance verification after local fine quantization is: The data amount of the electric energy meter harmonic data before and after the sub-sampling is obtained and the proportion is calculated, and the compression ratio is obtained; If the compression ratio is higher than or equal to the set required high compression ratio, it indicates that the compression ratio balance verification is successful, otherwise, the compression ratio balance verification fails.

10. The compression transmission method of three-phase electric energy meter harmonic data according to claim 9, characterized in that: The process of ensuring that the compression ratio and the amplitude error both meet the requirements through the combination operation of non-key harmonic redundancy pruning and key harmonic efficient coding is: Only the amplitude information of non-critical electric energy meter harmonics is reserved, the phase data is deleted, the non-critical electric energy meter harmonic data volume is reduced, the characteristic that the amplitude of critical electric energy meter harmonics fluctuates little in a short time is utilized, the complete amplitude is stored in the first frame, only the amplitude difference value of the previous frame is stored in the subsequent frame, the critical electric energy meter harmonic data volume is reduced, the quantization coefficient is normalized according to the maximum amplitude of the critical electric energy meter harmonics, the number of coding bits is reduced, and it is ensured that the total error after normalization is less than or equal to 2%.

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