State evaluation method for electric energy meter

Abstract

The invention relates to the technical field of equipment state evaluation, in particular to a state evaluation method for an electric energy meter. The method comprises the following steps: dividing a voltage signal curve of working voltage of the electric energy meter in a target time period to obtain a plurality of voltage signal segments; determining a first difference degree value according to the difference degree of different voltage signal segments on the time length, and determining a second difference degree value according to the difference degree of voltages at different moments in the same voltage signal segment; determining a third difference degree value according to the DTW distance between the adjacent voltage signal segments, and taking a mean value of the first difference degree value, the second difference degree value and the third difference degree value as a target evaluation value; and obtaining the average fault interval duration of the electric energy meter in the historical time period, and obtaining a state evaluation result of the electric energy meter according to the target evaluation value and the average fault interval duration. According to the technical scheme, the state of the electric energy meter can be evaluated more conveniently.

Description

Technical Field

[0001] The present application relates to the technical field of equipment status assessment, and in particular to a status assessment method for an electric energy meter. Background Art

[0002] The energy meter can measure the energy consumption in the circuit by measuring the work done by the current at the test node of the device to be measured within a certain period of time. The energy meter with remote communication capability can also transmit the electricity consumption data to the power company's management system in real time. By monitoring and analyzing the use of electricity, the energy meter can also allow users to understand the use of electricity more intuitively, so that they can take corresponding energy-saving measures.

[0003] For example, an electronic energy meter uses voltage and current transformers to sample the voltage and current signals in the circuit, and converts the sampled analog signals into digital signals through an analog / digital converter; a digital signal processor processes the digital signal, calculates the product of voltage and current, and obtains the instantaneous power value; the consumed electric energy is obtained by integrating the instantaneous power over time; the energy meter can also display the calculated electric energy value on a display screen.

[0004] The electric energy meter has a specific operating voltage range when measuring electric energy. For example, the operating voltage of a common single-phase electric energy meter may be 220V±10%, that is, within the voltage range of 198V to 242V, the electric energy meter can achieve relatively accurate measurement of electric energy.

[0005] When the status of the electric energy meter is abnormal, the working voltage of the electric energy meter may be in an unstable state. If the electric energy meter operates at an unstable working voltage for a long time, it may accelerate the aging of the internal components of the electric energy meter and shorten the service life of the electric energy meter. Therefore, it is necessary to evaluate the status of the electric energy meter to ensure that the electric energy meter operates within a relatively stable working voltage range. Summary of the invention

[0006] In order to realize the evaluation of the state of an electric energy meter, the present application provides a state evaluation method for an electric energy meter, comprising: obtaining a voltage signal curve of the working voltage of the electric energy meter within a target time period, performing zero-crossing detection on the voltage signal curve to obtain multiple voltage zero-point positions, and taking segments where a preset number of voltage zero-point positions are located in a continuous time sequence as candidate signal segments; when the duration of the candidate signal segment is greater than or equal to a first preset duration, taking the candidate signal segment as a voltage signal segment; when the duration of the candidate signal segment is less than the first preset duration, merging multiple adjacent candidate signal segments with durations less than the first preset duration to obtain a voltage signal segment; and selecting a voltage signal segment according to different voltage signal segments. A first difference degree value is determined according to the degree of difference in duration, and a second difference degree value is determined according to the degree of difference in voltage at different times within the same voltage signal segment; a third difference degree value is determined according to the DTW distance between adjacent voltage signal segments, and the average of the first difference degree value, the second difference degree value and the third difference degree value is used as the target evaluation value; the average fault interval duration of the electric energy meter in the historical time period is obtained, and the reliability value of the electric energy meter is obtained according to the target evaluation value and the average fault interval duration, so as to use the reliability value to output the status evaluation result of the electric energy meter; the reliability value is used to characterize the time interval between the current moment and the expected moment when the electric energy meter will fail next time.

[0007] In this way, the voltage signal curve of the working voltage of the electric energy meter within the target time period is obtained, and the voltage signal curve is periodically detected to determine the voltage signal segments with periodicity in the voltage signal curve. The reliability value of the electric energy meter can be determined based on the average failure interval duration of the electric energy meter according to the differences in the voltage signal segments, thereby obtaining the status evaluation result of the electric energy meter.

[0008] Optionally, the first difference degree value is determined in the following manner: , where H is the first difference value, M is the number of voltage signal segments, and norm is the normalization function. is the duration of the i-th voltage signal segment, To take the absolute value.

[0009] Optionally, the second difference degree value is determined by: , where E is the second difference value, M is the number of voltage signal segments, norm is the normalization function, and f is the sampling frequency of the voltage signal. is the duration of the i-th voltage signal segment, is the jth voltage in the i-th voltage signal segment, is the average voltage in the i-th voltage signal segment, To take the absolute value.

[0010] Optionally, the third difference degree value is determined by: , where G is the third difference value, M is the number of voltage signal segments, N is the preset neighborhood radius, and norm is the normalization function. is the DTW distance between the i-th voltage signal segment and the n-th other voltage signal segment in the neighborhood of the i-th voltage signal segment.

[0011] The DTW distance between two adjacent voltage signal segments can better reflect the degree of difference between the two voltage signal segments.

[0012] Optionally, obtaining the reliability value of the electric energy meter based on the target evaluation value and the average fault interval duration includes: performing an exponential operation on the square of the target evaluation value using an exponential function with a natural constant as the base to obtain an exponential operation value; multiplying the reciprocal of the exponential operation value by the average fault interval duration to obtain a reliability value; the reliability value is used to characterize the time interval between the current moment and the expected moment when the electric energy meter will next fail.

[0013] Optionally, the average fault interval duration of the electric energy meter in a historical time period is obtained by: determining the operating time of the electric energy meter in the historical time period, and determining the number of failures of the electric energy meter during the operating time; and taking the ratio of the operating time to the number of failures as the average fault interval duration.

[0014] Optionally, the reliability value is used to output the status assessment result of the electric energy meter, including: when the reliability value represents that the time interval between the current moment and the expected moment when the electric energy meter next fails is greater than or equal to a second preset duration, indicating that the status assessment result of the electric energy meter is good.

[0015] Optionally, the reliability value is used to output the status assessment result of the electric energy meter, including: when the reliability value represents that the time interval between the current moment and the expected moment when the electric energy meter next fails is less than a second preset duration, outputting a prompt message; the prompt message is at least used to prompt the expected moment when the electric energy meter next fails.

[0016] When the reliability value represents that the time interval between the current moment and the estimated moment when the electric energy meter will next fail is less than the second preset time length, an early warning of the moment when the electric energy meter may fail can be achieved.

[0017] Optionally, the method also includes: for a target voltage signal segment among multiple voltage signal segments whose duration is different from the average duration, the duration of the target voltage signal segment can be resampled to the average duration; the average duration is equal to the average value of the durations of all voltage signal segments.

[0018] The technical solution provided by the embodiments of the present application may include the following beneficial effects: by obtaining the voltage signal curve of the electric energy meter within the target time period, and performing periodic detection on the voltage signal curve, to determine the voltage signal segments with periodicity in the voltage signal curve; based on the differences in the voltage signal segments and the average failure interval duration of the electric energy meter in the historical time period, the reliability value of the electric energy meter can be obtained, which can more conveniently realize the evaluation of the status of the electric energy meter.

[0019] For voltage signal segments whose duration is equal to the average duration, the target evaluation value is determined according to the difference values ​​of the voltage signals at corresponding positions of different voltage signal segments. The target evaluation value can better characterize the degree of difference between different voltage signal segments, thereby obtaining a more accurate reliability value of the electric energy meter and better realizing the evaluation of the status of the electric energy meter.

[0020] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a flow chart of a method for evaluating the state of an electric energy meter according to an exemplary embodiment. DETAILED DESCRIPTION

[0022] First, a brief introduction is given to the application scenarios of the embodiments of the present application. In the application scenarios of the present application, when there is an abnormality in the components of the electric energy meter, the working voltage of the electric energy meter may be in an unstable state, thereby affecting the electric energy measurement results of the electric energy meter; or, when the electric energy meter works under an unstable working voltage, it will accelerate the damage of the components in the electric energy meter, thereby further affecting the electric energy measurement results of the electric energy meter. Therefore, it is necessary to evaluate the state of the electric energy meter to ensure the working state of the electric energy meter.

[0023] In view of the above technical problems, the present application provides a method for evaluating the status of an electric energy meter. Figure 1 is a flow chart of a method for evaluating the status of an electric energy meter according to an exemplary embodiment. The method for evaluating the status of an electric energy meter provided in the embodiment of the present application can be applied to a terminal device for monitoring the electric energy meter, such as Figure 1 As shown, the method includes the following steps.

[0024] In step S101, a voltage signal curve of the working voltage of the electric energy meter within a target time period is obtained, and the voltage signal curve is divided into a plurality of voltage signal segments.

[0025] The voltage signal curve includes multiple voltage signals of the electric energy meter within the target time period. The working voltage of the electric energy meter when working may have a certain periodicity. The voltage signal curve is divided to obtain multiple voltage signal segments, and the periodicity of the voltage signal can be analyzed based on the multiple pressure signal segments obtained.

[0026] It should be noted that the voltage signal curve obtained in the embodiment of the present application may be a voltage signal curve after filtering the original voltage signal curve of the working voltage of the electric energy meter during the target time period; the filtering process may be implemented, for example, by wavelet transform or adaptive filter, and the embodiment of the present application does not constitute a limitation on the specific algorithm of the filtering process.

[0027] When the electric energy meter operates with a relatively stable operating voltage period, the durations of multiple voltage segments in the voltage signal curve of the obtained operating voltage are close to each other, for example, the durations of multiple voltage segments are the same; however, when the operating state of the electric energy meter fails or is likely to fail, the period of the operating voltage of the electric energy meter when it is working may fluctuate. Therefore, obtaining multiple voltage signal segments by dividing the voltage signal curve helps to provide data support for the reliability of the electric energy meter.

[0028] Zero-crossing detection can be performed on the voltage signal curve to obtain multiple voltage zero point positions, and the segments where a preset number of voltage zero point positions are consecutive in time sequence are used as candidate signal segments; when the duration of the candidate signal segment is greater than or equal to the first preset duration, the candidate signal segment is used as the voltage signal segment; when the duration of the candidate signal segment is less than the first preset duration, multiple adjacent candidate signal segments with a duration less than the first preset duration are merged to obtain a voltage signal segment.

[0029] The voltage zero point position usually represents the moment when the voltage waveform switches from one half cycle to the next half cycle. Therefore, the voltage zero point position can be used as a reliable basis for analyzing the periodicity of the working voltage of the electric energy meter. By performing zero-crossing detection on the voltage signal curve, the zero-crossing point of the voltage signal in the voltage signal curve can be determined, thereby accurately determining the periodic changes of the voltage signal of the working voltage of the electric energy meter.

[0030] The first preset time length can be set according to actual needs. For example, the first preset time length can be between 15ms and 30ms.

[0031] The preset number can be set according to actual needs, for example, the preset number can be between 3 and 6; by selecting a preset number of consecutive segments where the voltage zero point positions are located as candidate signal segments, it can be ensured that the obtained segments have potential periodicity, thereby improving the accuracy of subsequent processing processes.

[0032] When the duration of the candidate signal segment is greater than or equal to the first preset duration, the candidate signal segment can more effectively represent the periodicity of the working voltage of the electric energy meter, the duration of the selected candidate signal segment is highly representative, and the candidate signal segment can be used as a voltage signal segment.

[0033] When the duration of the candidate signal segment is less than the first preset duration, it indicates that the selected candidate signal may be a part of the periodic segment of the working voltage of the electric energy meter. If there are other candidate signal segments with a duration less than the first preset duration in the neighborhood of the candidate signal segment with a duration less than the first preset duration, multiple adjacent candidate signal segments with a duration less than the first preset duration can be merged to obtain a voltage signal segment, so that the voltage signal segment obtained after the merger can effectively represent the periodic characteristics of the working voltage of the electric energy meter.

[0034] In step S102, a first difference value is determined according to the difference in duration between different voltage signal segments, and a second difference value is determined according to the difference in voltage at different times within the same voltage signal segment.

[0035] For example, when the electric energy meter operates in a relatively stable working state, the periodicity of the working voltage of the electric energy meter is relatively stable; however, when the electric energy meter fails, the amplitude or duration of the voltage signal of the working voltage of the electric energy meter may deviate. Therefore, the duration of the voltage signal segment can be resampled to an average duration to facilitate determining the reliability of the electric energy meter.

[0036] Resampling includes upsampling and downsampling. For a target voltage signal segment among multiple voltage signal segments whose duration is different from the average duration, the duration of the target voltage signal segment can be resampled to the average duration, including: when the duration of the target voltage signal segment is greater than the average duration, downsampling the target voltage signal segment so that the duration of the downsampled target voltage signal segment is equal to the average duration; when the duration of the target voltage signal segment is less than the average duration, upsampling the target voltage signal segment so that the duration of the upsampled target voltage signal segment is equal to the average duration.

[0037] In this way, by resampling the duration of the voltage signal segment to the average duration, it is convenient to analyze the shape of the voltage signal within the same duration, thereby better determining the reliability of the electric energy meter.

[0038] In one embodiment, the first difference degree value is determined by: , where H is the first difference value, M is the number of voltage signal segments, and norm is the normalization function. is the duration of the i-th voltage signal segment, To take the absolute value.

[0039] Since the multiple determined voltage signal segments are periodic segments in the voltage signal curve of the working voltage of the electric energy meter, if the difference between the durations of different voltage signal segments is large, it means that the stability of the cycle of the working voltage of the electric energy meter is low, and the higher the probability of abnormalities in the components in the electric energy meter, comparing the durations of different voltage signal segments with the average duration can enable the first difference degree value to better characterize the degree of difference in duration between different voltage signal segments, thereby characterizing the degree of fluctuation of the cycle of the electric energy meter.

[0040] In one embodiment, the second difference degree value is determined by: , where E is the second difference value, M is the number of voltage signal segments, norm is the normalization function, and f is the sampling frequency of the voltage signal. is the duration of the i-th voltage signal segment, is the jth voltage in the i-th voltage signal segment, is the average voltage in the i-th voltage signal segment, To take the absolute value.

[0041] The greater the difference between the voltage at different times in the same voltage signal segment and the average voltage, the greater the fluctuation of the working voltage of the electric energy meter at different times in the same voltage signal segment. This fluctuation of the working voltage may accelerate the damage of the components in the electric energy meter, or this fluctuation of the working voltage may be caused by abnormalities in the components in the electric energy meter. Therefore, by comparing the voltage at different times in the same voltage signal segment with the average voltage, it is helpful to better realize the evaluation of the status of the electric energy meter.

[0042] In step S103, a third difference degree value is determined according to the DTW distance between adjacent voltage signal segments, and an average of the first difference degree value, the second difference degree value and the third difference degree value is used as a target evaluation value.

[0043] The target evaluation value is used to characterize the degree of difference between different voltage signal segments. For example, the difference value of the voltage signals at corresponding positions of two voltage signal segments can be determined to analyze the degree of difference in signal shape between the two voltage signal segments. By comparing the difference values ​​of the voltage signals at corresponding positions of multiple voltage signals, the degree of difference between the multiple voltage signal segments can be reflected in an integrated manner. Therefore, according to the obtained target evaluation value, the degree of difference between different voltage signal segments can be better characterized.

[0044] In one embodiment, the third difference degree value is determined by: , where G is the third difference value, M is the number of voltage signal segments, N is the preset neighborhood radius, and norm is the normalization function. is the DTW distance between the i-th voltage signal segment and the n-th other voltage signal segment in the neighborhood of the i-th voltage signal segment.

[0045] DTW (Dynamic Time Warping) distance is a distance used to measure the difference between two time series. DTW distance can be applied to fields such as speech recognition, gesture recognition, and bioinformatics.

[0046] The DTW distance between two time series is negatively correlated with the similarity between the two time series; the smaller the DTW distance between the two time series, the higher the similarity between the two time series; conversely, the larger the DTW distance between the two time series, the lower the similarity between the two time series.

[0047] The DTW distance between adjacent voltage signal segments can reflect the fluctuation of the working voltage of the electric energy meter.

[0048] Since the first difference degree value is used to characterize the difference degree in duration between different voltage signal segments, the second difference degree value is used to characterize the difference degree of voltage at different times within the same voltage signal segment among multiple voltage signal segments, the third difference degree value is determined based on the DTW distance between adjacent voltage signal segments among the multiple voltage signal segments. The average of the first difference degree value, the second difference degree value and the third difference degree value is used as the target evaluation value. The target evaluation value can evaluate the fluctuation of the working voltage of the electric energy meter from at least two aspects: the difference within the same voltage signal segment at different times and the difference between different voltage signal segments.

[0049] In step S104, the average fault interval duration of the electric energy meter in the historical time period is obtained, and the reliability value of the electric energy meter is obtained according to the target evaluation value and the average fault interval duration, so as to output the status evaluation result of the electric energy meter using the reliability value.

[0050] Since the target evaluation value can better characterize the degree of difference between different voltage signal segments, and when the reliability of the electric energy meter is at a high level, for example, when the electric energy meter has 100% of its remaining service life, the voltage signals of the working voltage of the electric energy meter when working in different time periods are closer, the obtained target evaluation value will be smaller. Therefore, the reliability value of the electric energy meter can be determined through the target evaluation value and the average failure interval time.

[0051] The reliability value can be used to characterize the time interval between the current moment and the expected time when the electric energy meter will next fail. For example, when the time interval between the current moment and the expected time when the electric energy meter will next fail is less than or equal to the second preset time, it means that the electric energy meter will fail in the near future or even cannot be used anymore. To ensure the normal use of the equipment that provides the voltage signal of the electric energy meter, the electric energy meter can be replaced with a new one. The second preset time can be set according to actual needs. For example, the second preset time can be between 10 hours and 24 hours.

[0052] Through the state assessment method for an electric energy meter provided in an embodiment of the present application, a voltage signal curve of the electric energy meter within a target time period is obtained, and the voltage signal curve is periodically detected to determine a voltage signal segment with periodicity in the voltage signal curve; based on the differences in the voltage signal segments and the average failure interval duration of the electric energy meter in a historical time period, the reliability value of the electric energy meter can be obtained. Compared with obtaining the environmental load surface of the electric energy meter and determining the reliability, the state assessment of the electric energy meter can be achieved more conveniently.

[0053] For voltage signal segments whose duration is equal to the average duration, a target evaluation value is determined according to the difference values ​​of voltage signals at corresponding positions of different voltage signal segments. The target evaluation value can better characterize the degree of difference between different voltage signal segments, thereby obtaining a more accurate reliability value of the electric energy meter and better realizing the evaluation of the status of the electric energy meter.

[0054] In one embodiment, determining the target evaluation value based on the difference values ​​of voltage signals at corresponding positions of different voltage signal segments includes: determining a voltage signal segment combination from multiple voltage signal segments with a duration equal to an average duration, the voltage signal segment combination including two voltage signal segments that are different from each other; determining a difference degree value corresponding to the voltage signal segment combination based on the difference values ​​of voltage signals at corresponding positions of two voltage signal segments in the voltage signal segment combination; determining target average values ​​of different difference degree values ​​corresponding to different voltage signal segment combinations, and determining the target evaluation value based on the target average value.

[0055] For example, when the number of different voltage signal segments is 10, if a voltage signal segment combination including two voltage signal segments is selected from the 10 voltage signal segments, 5×9=45 voltage signal segment combinations can be determined.

[0056] The difference degree value corresponding to the voltage signal segment combination is determined based on the difference value of the voltage signals of two voltage signal segments at corresponding positions in the voltage signal segment combination. The difference degree value can be used to characterize the difference degree between the two voltage signal segments in the voltage signal segment combination; the difference degree value can, for example, be equal to the average of multiple difference values ​​of the voltage signals at different corresponding positions; the difference value of the voltage signals of the two voltage signal segments at corresponding positions can be the absolute value of the difference between the voltage signals of the two voltage signal segments at corresponding positions.

[0057] For example, taking the number of data points included in the voltage signal segment as 5, the voltage signal segment combination includes a first voltage signal segment and a second voltage signal segment, and the data of each data point in the first voltage signal segment, that is, the voltage signals at different times of the first voltage signal segment are A and B respectively. 1 , A 2 , A 3 , A 4 and A 5 , the voltage signals at different moments of the second voltage signal segment are B 1 , B 2 , B 3 , B 4 and B 5 .

[0058] The difference values ​​of the voltage signals of the first voltage signal segment and the second voltage signal segment at the corresponding positions are respectively , , , as well as , the average of these multiple difference values ​​can be used as the difference degree value corresponding to the voltage signal segment combination.

[0059] In this way, since the difference degree value can characterize the difference degree between the voltage signal segments in the voltage signal segment combination, the target average values ​​of different difference degree values ​​corresponding to different voltage signal segment combinations are determined. The target average value can reflect the difference degree between multiple periodic voltage signal segments within the target time period. The target evaluation value determined according to the target average value can reflect the abnormality degree of the electric energy meter within the target time period, thereby providing a reference for determining the reliability of the electric energy meter.

[0060] The following uses an exemplary calculation formula as an example to explain the process of obtaining the target average values ​​of different difference degree values ​​corresponding to different voltage signal segment combinations in the embodiment of the present application: , where G is the target average value, M is the number of voltage signal segments, i is a positive integer less than M; k is a positive integer less than or equal to M, and k is a positive integer greater than i; N is the number of voltage signals in the voltage signal segment, j is a positive integer less than or equal to N, and norm is the normalization function. is the magnitude of the jth voltage signal in the i-th voltage signal segment, is the magnitude of the jth voltage signal in the kth voltage signal segment, and the normalization function may be a logarithmic function, for example.

[0061] In one embodiment, determining the target evaluation value according to the target average value includes: determining a first fluctuation value of the duration of multiple voltage signal segments before resampling; and taking an average value of the first fluctuation value and the target average value as the target evaluation value.

[0062] The durations of multiple voltage signal segments before resampling may be different. The first fluctuation value of the durations of the multiple voltage signal segments before resampling can characterize the degree of fluctuation of the durations of the multiple voltage signal segments before resampling. The first fluctuation value can be determined based on the variance, standard deviation and range of the durations of the multiple voltage signal segments before resampling.

[0063] In this way, the average value of the first fluctuation value and the target average value is used as the target evaluation value. Since the first fluctuation value can characterize the degree of fluctuation in the duration of multiple voltage signal segments before resampling, the target evaluation value can provide a better reference for estimating the reliability of the electric energy meter.

[0064] In one embodiment, the target evaluation value is determined based on the target average value, including: determining the voltage signal average value of the voltage signal segment before resampling; determining a second fluctuation value between different voltage signal average values ​​corresponding to different voltage signals, the second fluctuation value being used to characterize the degree of difference between different voltage signal average values; and taking the average value of the second fluctuation value and the target average value as the target evaluation value.

[0065] By determining the voltage signal average value of the voltage signal segment before resampling, and determining a second fluctuation value between different voltage signal average values ​​corresponding to different voltage signals, the second fluctuation value can characterize the degree of fluctuation of the voltage signal average values ​​of different voltage signals within a target time period; wherein the second fluctuation value can be determined based on the variance, standard deviation and range of different voltage signal average values ​​corresponding to different voltage signals.

[0066] In this way, since the second fluctuation value can characterize the fluctuation degree of the voltage signal average value of different voltage signals within the target time period, the average of the second fluctuation value and the target average value is used as the target evaluation value, and the target evaluation value can better provide a reference for estimating the reliability of the electric energy meter.

[0067] In one embodiment, the reliability value of the electric energy meter is obtained according to the target evaluation value and the average fault interval duration, including: performing an exponential operation on the square of the target evaluation value using an exponential function with a natural constant as the base to obtain an exponential operation value; multiplying the reciprocal of the exponential operation value by the average fault interval duration to obtain a reliability value; the reliability value is used to characterize the time interval between the current moment and the expected moment when the electric energy meter will next fail.

[0068] The target evaluation value can represent the probability of an abnormality in the electric energy meter. The higher the probability of an abnormality in the electric energy meter at the current moment, the shorter the time interval between the current moment and the estimated moment when the electric energy meter will next fail, and the lower the reliability of the electric energy meter.

[0069] The exponential operation value is obtained by performing an exponential operation on the average of the target evaluation value, and the reliability value is obtained by multiplying the reciprocal of the exponential operation value by the average fault interval. This can not only realize the normalization processing of the target evaluation value, but also use the obtained reliability value to represent the time interval between the current time and the expected time when the electric energy meter will next fail.

[0070] In one embodiment, the average fault interval duration of the electric energy meter in a historical time period is obtained by: determining the operating time of the electric energy meter in the historical time period, and determining the number of failures of the electric energy meter during the operating time; and taking the ratio of the operating time to the number of failures as the average fault interval duration.

[0071] Mean Time Between Failures (MTBF) is one of the important indicators for measuring product reliability. It indicates the average length of time a product can work normally between two consecutive failures.

[0072] In this way, by determining the mean time between failures, a reference can be provided for determining the reliability of the electric energy meter at the current moment.

[0073] In one embodiment, the reliability value is used to output the status evaluation result of the electric energy meter, including: when the reliability value represents that the time interval between the current moment and the expected moment when the electric energy meter will next fail is greater than or equal to a second preset time length, indicating that the status evaluation result of the electric energy meter is good.

[0074] The second preset duration can be set according to actual needs; the reliability value indicates that the time interval between the current moment and the expected time when the electric energy meter will next fail is greater than or equal to the second preset duration, indicating that the time until the next failure of the electric energy meter is relatively long, and it can be determined that the working status of the electric energy meter is normal.

[0075] In one embodiment, the reliability value is used to output the status assessment result of the electric energy meter, including: when the reliability value represents that the time interval between the current moment and the expected moment when the electric energy meter next fails is less than a second preset time length, outputting a prompt message; the prompt message is at least used to prompt the expected moment when the electric energy meter next fails.

[0076] When the reliability value represents that the time interval between the current moment and the estimated moment when the electric energy meter next fails is less than the second preset time length, it indicates that the time interval between the electric energy meter and the next failure is short, and the electric energy meter can be replaced or a maintenance plan can be formulated in advance so that the electric energy meter can be replaced in advance to ensure that the electric energy meter in use is always at a high reliability; or, the materials required for maintenance can be prepared in advance to shorten the total time required for subsequent maintenance of the electric energy meter.

[0077] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary technical means in the art that are not disclosed in the present application, and the specification and embodiments are only considered as exemplary.

[0078] It should be understood that the present application is not limited to the exact construction that has been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof.

Claims

1. A method for evaluating the state of an electric energy meter, characterized in that: include: A voltage signal curve of the working voltage of the electric energy meter within a target time period is obtained, and a zero-crossing detection is performed on the voltage signal curve to obtain a plurality of voltage zero-point positions, and segments where a preset number of voltage zero-point positions are consecutive in time sequence are located are used as candidate signal segments; when the duration of the candidate signal segment is greater than or equal to a first preset duration, the candidate signal segment is used as the voltage signal segment; When the duration of the candidate signal segment is less than the first preset duration, a plurality of adjacent candidate signal segments whose duration is less than the first preset duration are merged to obtain a voltage signal segment; Determine a first difference value according to the difference in duration between different voltage signal segments, and determine a second difference value according to the difference in voltage at different times within the same voltage signal segment; Determine a third difference degree value according to the DTW distance between adjacent voltage signal segments, and use an average of the first difference degree value, the second difference degree value, and the third difference degree value as a target evaluation value; Obtain the average fault interval time of the electric energy meter in the historical time period, and obtain the reliability value of the electric energy meter according to the target evaluation value and the average fault interval time, so as to output the state evaluation result of the electric energy meter by using the reliability value; The reliability value is used to characterize the time interval between the current time and the estimated time when the electric energy meter will fail next time.

2. The state assessment method for an electric energy meter according to claim 1, characterized in that: The first difference degree value is determined in the following manner: , where H is the first difference value, M is the number of voltage signal segments, and norm is the normalization function. is the duration of the i-th voltage signal segment, To take the absolute value.

3. The state assessment method for an electric energy meter according to claim 1, characterized in that: The second difference degree value is determined in the following manner: , where E is the second difference value, M is the number of voltage signal segments, norm is the normalization function, and f is the sampling frequency of the voltage signal. is the duration of the i-th voltage signal segment, is the jth voltage in the i-th voltage signal segment, is the average voltage in the i-th voltage signal segment, To take the absolute value.

4. The state assessment method for an electric energy meter according to claim 1, characterized in that: According to the target evaluation value and the mean time between failures, the reliability value of the electric energy meter is obtained, including: An exponential operation is performed on the square of the target evaluation value using an exponential function with a natural constant as a base to obtain an exponential operation value; and a reciprocal of the exponential operation value is multiplied by the mean failure interval time to obtain a reliability value.

5. The method for evaluating the state of an electric energy meter according to claim 1, characterized in that: The average fault interval duration of the electric energy meter in the historical time period is obtained by: Determine the operating time of the electric energy meter during the historical time period, and determine the number of failures of the electric energy meter during the operating time; The ratio of the operating time to the number of failures is used as the average failure interval time.

6. The state assessment method for an electric energy meter according to claim 1, characterized in that: The reliability value is used to output the status assessment results of the electric energy meter, including: When the reliability value indicates that the time interval between the current moment and the estimated moment when the electric energy meter next fails is greater than or equal to the second preset time, it is prompted that the state evaluation result of the electric energy meter is good.

7. The state assessment method for an electric energy meter according to claim 1, characterized in that: The reliability value is used to output the status assessment results of the electric energy meter, including: When the reliability value represents that the time interval between the current moment and the estimated moment when the electric energy meter next fails is less than a second preset duration, a prompt message is output; the prompt message is at least used to prompt the estimated moment when the electric energy meter next fails.

8. The state assessment method for an electric energy meter according to claim 1, characterized in that: The method further comprises: For a target voltage signal segment whose duration is different from the average duration among multiple voltage signal segments, the duration of the target voltage signal segment can be resampled to the average duration; the average duration is equal to the average duration of all voltage signal segments.

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