Online monitoring method for metering performance of voltage transformer, medium and terminal

Abstract

The invention is suitable for the technical field of electric energy metering, and relates to a voltage transformer metering performance online monitoring method, medium and terminal, and the method comprises the steps: S10, collecting M groups of secondary side signals of a three-phase voltage transformer, the number of channels being N; s20, assuming that an analysis window is L, and performing standardization processing on the analysis window; s30, calculating the average value of the amplitude and the phase after standardization processing, and constructing the measurement performance characterization quantity of the mutual inductor according to the amplitude and the phase data of the secondary side of the mutual inductor; s40, analyzing the metering performance of the voltage transformer of the N channel, wherein the metering performance of the voltage transformer is divided into a normal state and an out-of-tolerance state; s50, identifying the metering performance state of the mutual inductor of each channel, and calculating a virtual standard for the mutual inductor with the normal metering state; and S60, calculating the ratio error and the angular error of the N-channel voltage transformer. According to the invention, the ratio and the angular difference of the mutual inductor are used as the metering performance of the mutual inductor and are analyzed as a whole, so that the monitoring efficiency and the identification precision are higher.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric energy metering, and particularly relates to an online monitoring method, medium and terminal for the metering performance of a voltage transformer. Background Art

[0002] Due to its good insulation characteristics, a capacitor voltage transformer (CVT) is widely used in high-voltage application scenarios.

[0003] The patent with the publication number CN104155627A provides an error characteristic detection method for an ultra-high voltage capacitor voltage transformer, including Step 1: performing on-site handover detection of the transformer on the electromagnetic voltage transformer in an off-line state, and correcting the electromagnetic voltage transformer according to the detection results; Step 2: using the corrected electromagnetic voltage transformer as a standard voltage transformer, and performing on-line error detection on the capacitor voltage transformer by using an error on-line detection device; the capacitor voltage transformer is respectively connected to the transformer outlet and the high-reactance outlet of the three-phase bus; the electromagnetic voltage transformer is connected to the bus between the transformer and the high reactance. This patent also uses a corrected electromagnetic voltage transformer as a standard voltage transformer, and then compares the capacitor voltage transformer to be detected with it, and finally obtains the error result. This solution also cannot detect the error of the transformer under real-time working conditions, and there are deviations in the monitoring results.

[0004] Therefore, how to provide a monitoring method for the metering performance of a voltage transformer with high monitoring efficiency and recognition accuracy is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an online monitoring method for the metering performance of a voltage transformer to solve the problems of low monitoring efficiency and recognition accuracy of the metering performance of a voltage transformer in the prior art; in addition, the present invention also provides an online monitoring medium and terminal for the metering performance of a voltage transformer.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides an online monitoring method for the metering performance of a voltage transformer, including the following steps:

[0008] S10. Collect the secondary side signals of M groups of three-phase voltage transformers, and the number of channels is N;

[0009] S20. Assume that the analysis window is L and perform normalization processing on it;

[0010] S30. Calculate the mean values of the amplitudes and phases after the normalization process, and construct a metrological performance characterization quantity for the instrument transformer based on the amplitude and phase data on the secondary side of the instrument transformer.

[0011] S40. Analyze the metrological performance of the voltage instrument transformers in N channels. The metrological performance of the voltage instrument transformers is divided into a normal state and an out-of-tolerance state.

[0012] S50. Identify the metrological performance states of the instrument transformers in each channel, and calculate the virtual standard for the instrument transformers with normal metrological states.

[0013] S60. Calculate the ratio error and phase error of the voltage instrument transformers in N channels.

[0014] Furthermore, in the step S10, the amplitude signal is: ;

[0015] where , is the number of channels, M is the number of groups of three-phase voltage instrument transformers, The superscript represents the time point, represents the th channel, that is, represents the amplitude at the channel at time.

[0016] The phase signal is: ;

[0017] where The superscript represents the time point, represents the th channel, that is, represents the channel at time.

[0018] Furthermore, in the step S20, the amplitude data is: ;

[0019] The amplitude data after normalization is: ;

[0020] where , ( , ), is the mean value of , is the variance of ;

[0021] Similarly, the phase data after normalization is: ;

[0022] Among them, , ( , ), is the mean value of is the variance of

[0023] Furthermore, the specific steps of step S30 are as follows:

[0024] S301. The mean values of amplitude and phase are successively: ; ;

[0025] Among them, is the mean value of is the mean value of

[0026] S302. The measurement performance characterization quantities of channel current transformers are successively .

[0027] Furthermore, the specific steps of step S40 are as follows:

[0028] S401. Randomly select 2 points in as the initial cluster ;

[0029] S402. Calculate the distances from all sample points to and label them as the category of the nearest cluster center;

[0030] S403. Calculate the centers of the two-category sample points in step S402 as the new cluster centers;

[0031] S404. Repeat steps S402 to S403 until the cluster centers no longer change or reach the maximum number of iterations;

[0032] S405. Finally, obtain the cluster centers , and the number of samples corresponding to the two cluster centers .

[0033] Furthermore, the specific steps of step S50 are as follows:

[0034] S501. Since the number of current transformers in the out-of-tolerance state is less than the number of normal current transformers, when , then the corresponding sample point is a normal potential transformer; otherwise the corresponding sample point is a normal potential transformer;

[0035] S502. Assume the corresponding sample point is a normal potential transformer, calculate the mean value of all normal potential transformers to obtain a virtual standard , where is the standard value corresponding to the amplitude, is the standard value corresponding to the amplitude.

[0036] Further, in the step S60:

[0037] The ratio error of the channel voltage transformer is: .

[0038] Further, in the step S60:

[0039] The angular error of the channel voltage transformer is: .

[0040] In a second aspect, the present invention also provides a computer-readable storage medium, where the storage medium stores a computer program, and when the computer program is executed by a processor, the above-mentioned method is implemented.

[0041] In a third aspect, the present invention also provides an electronic terminal, including: a processor and a memory; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory so that the terminal executes the above-mentioned method.

[0042] Compared with the prior art, the on-line monitoring method, medium and terminal for the metrological performance of the potential transformer provided by the present invention have at least the following beneficial effects:

[0043] The existing verification method is off-line verification with power cut. The same voltage signal is applied to the potential transformer to be verified and the high-precision standard device at the same time. The difference between the output value of the potential transformer to be verified and the output value of the standard device is the static error of the potential transformer. This method has low monitoring efficiency and recognition accuracy. The process of the present invention is simple and the operation is convenient. By analyzing the secondary side (amplitude and phase) of the voltage transformer, the angular error is calculated according to the phase. The ratio error and the angular error are calculated completely independently. The ratio and the angular error of the potential transformer are used as the metrological performance of the potential transformer, and they are analyzed as a whole to identify the potential transformer with normal metrological performance, so as to obtain the virtual standard of the potential transformer. According to the virtual standard, the metrological error of each channel potential transformer is obtained, and the monitoring efficiency and recognition accuracy are higher. Brief Description of the Drawings

[0044] To more clearly illustrate the solution of the present invention, the following will give a brief introduction to the drawings required in the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0045] Figure 1 It is a flowchart of an online monitoring method for the metrological performance of a voltage transformer provided by an embodiment of the present invention. Detailed Embodiments

[0046] To facilitate the understanding of the present invention, the following will give a more comprehensive description of the present invention with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0048] The present invention provides an online monitoring method for the metrological performance of a voltage transformer, which is applied to the real-time monitoring process of the error characteristics of a capacitive voltage transformer (CVT). The online monitoring method for the metrological performance of a voltage transformer includes the following steps:

[0049] S10. Collect the secondary side signals of M groups of three-phase voltage transformers, and the number of channels is N; S20. Assume that the analysis window is L and perform normalization processing on it; S30. Calculate the mean values of the amplitude and phase after normalization processing, and construct a metrological performance characterization quantity of the transformer based on the amplitude and phase data of the secondary side of the transformer; S40. Analyze the metrological performance of the voltage transformer with N channels. The metrological performance of the voltage transformer is divided into a normal state and an out-of-tolerance state; S50. Identify the metrological performance states of each channel of the transformer, and calculate a virtual standard based on the transformers with normal metrological states; S60. Calculate the ratio error and phase angle error of the voltage transformer with N channels.

[0050] The present invention takes the ratio and phase angle error of the transformer as the metrological performance of the transformer and analyzes them as a whole, with higher monitoring efficiency and identification accuracy.

[0051] To enable those skilled in the art to better understand the solution of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings.

[0052] The present invention provides an on-line monitoring method for the metering performance of a voltage transformer, which is applied to the real-time monitoring process of the error characteristics of a capacitive voltage transformer (CVT). The actual conversion relationship between the primary voltage and the secondary voltage of the transformer is: ;

[0053] wherein, 、 are the measured values of the primary side voltage and the secondary side voltage of the voltage transformer in sequence, is the rated transformation ratio of the voltage transformer, is the error of the voltage transformer. It can be seen from the above formula that there is a linear relationship between the secondary side signal and the primary side signal of the voltage transformer. In the application scenarios of voltage levels of 220 kV and above, for multiple groups of transformers connected under the same bus, their primary side signals are the same. When the transformer has no error, its secondary side information should be exactly the same. Based on the above analysis, the embodiment of the present invention adopts a clustering analysis method to identify a small number of out-of-tolerance transformers in the transformer cluster. As shown in Figure 1 , in this embodiment, the on-line monitoring method for the metering performance of the voltage transformer includes the following steps:

[0054] S10. Collect the secondary side signals of M groups of three-phase voltage transformers, and the number of channels is N.

[0055] Specifically, in this embodiment, the amplitude signal is: ;

[0056] where , is the number of channels, M is the number of groups of three-phase voltage transformers, The superscript represents the time point, represents the th channel, that is represents the amplitude at the th channel at time

[0057] The phase signal is: ;

[0058] wherein, The superscript represents the time point, represents the th channel. That is represents the phase at the th channel at time

[0059] S20. Assume that the analysis window is L ( < ), perform standardization processing on it.

[0060] Specifically, in this embodiment, the amplitude data is: ;

[0061] The standardized amplitude data is: ;

[0062] Among them , ( , ), is 's mean value, is 's variance.

[0063] Furthermore, in this embodiment, similarly, the standardized phase data is: ;

[0064] Among them, , ( , ), is 's mean value, is 's variance.

[0065] S30. Calculate the mean values of the amplitude and phase after standardization processing, and construct a metering performance characterization quantity of the transformer with the amplitude and phase data on the secondary side of the transformer.

[0066] Specifically, in this embodiment, the specific steps of step S30 are as follows:

[0067] S301. The mean values of the amplitude and phase are successively: ; ;

[0068] Among them, is 's mean value, is 's mean value.

[0069] S302. The metering performance characterization quantities of the channel transformers are successively , where

[0070] S40. Analyze the metrological performance of the voltage transformers in N channels. The metrological performance of the voltage transformers can be divided into a normal state and an out-of-tolerance state. Among them, the proportion of out-of-tolerance transformers is relatively small, generally less than 1 / 3. Therefore, perform cluster analysis on the metrological indexes of the voltage transformers in N channels, and set the number of clusters to 2, that is, divide the voltage transformers in N channels into 2 categories, one is the normal state and the other is the out-of-tolerance state.

[0071] Specifically, in this embodiment, the specific steps of step S40 are as follows:

[0072] S401. Randomly select 2 points in as the initial cluster .

[0073] S402. Calculate the distances from all sample points to , and mark them as the category of the nearest cluster center.

[0074] S403. Calculate the centers of the sample points of the two categories in S402 as the new cluster centers.

[0075] S404. Repeat steps S402 and S403 until the cluster centers no longer change or reach the maximum number of iterations.

[0076] S405. Finally, obtain the cluster centers , and the number of samples corresponding to the two cluster centers .

[0077] S50. Identify the metrological performance states of the transformers in each channel, and calculate the virtual standard according to the transformers with normal metrological states.

[0078] Specifically, in this embodiment, the specific steps of step S50 are as follows:

[0079] S501. The number of out-of-tolerance transformers is less than the number of normal transformers. When , then the corresponding sample points are normal transformers, otherwise the corresponding sample points are normal transformers.

[0080] S502. Assume that the corresponding sample points are normal transformers, calculate the mean value of all transformers with normal states, and obtain the virtual standard , where is the standard value corresponding to the amplitude, is the standard value corresponding to the amplitude.

[0081] S60. Calculate the ratio error and phase angle error of the voltage transformers in N channels.

[0082] Specifically, in this embodiment, The ratio error of the channel voltage transformer is: ;

[0083] That is: .

[0084] The phase angle error of the channel voltage transformer is: ;

[0085] That is: .

[0086] The embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, any one of the methods in this embodiment is implemented.

[0087] The embodiment of the present invention also provides an electronic terminal, including: a processor and a memory; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the terminal executes any one of the methods in this embodiment.

[0088] For the computer-readable storage medium in this embodiment, those of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to the computer program. The aforementioned computer program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps including the above method embodiments; and the aforementioned storage medium includes: various media such as ROM, RAM, magnetic disk or optical disc that can store program codes.

[0089] The electronic terminal provided in this embodiment includes a processor, a memory, a transceiver and a communication interface. The memory and the communication interface are connected to the processor and the transceiver and complete communication with each other. The memory is used to store a computer program, the communication interface is used for communication, and the processor and the transceiver are used to run the computer program, so that the electronic terminal executes each step of the above method.

[0090] The on-line monitoring method, medium and terminal for the metrological performance of a voltage transformer described in the above embodiments, compared with the prior art, the existing calibration method is off-line calibration with power cut. The same voltage signal is applied to the transformer under test and the high-precision standard device at the same time. The difference between the output value of the transformer under test and the output value of the standard device is the static error of the transformer. This method has low monitoring efficiency and identification accuracy. The process of the present invention is simple and the operation is convenient. By analyzing the secondary side (amplitude and phase) of the voltage transformer, the angular difference is calculated according to the phase. The ratio difference and the angular difference are calculated completely independently. The ratio and the angular difference of the transformer are used as the metrological performance of the transformer and analyzed as a whole to identify the transformer with normal metrological performance, so as to obtain the virtual standard of the transformer. According to the virtual standard, the metrological errors of the transformers in each channel are obtained, and the monitoring efficiency and identification accuracy are higher.

[0091] Obviously, the embodiments described above are only the preferred embodiments of the present invention, rather than all embodiments. The preferred embodiments of the present invention are given in the drawings, but they do not limit the patent scope of the present invention. The present invention can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosed content of the present invention more thorough and comprehensive. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing specific embodiments, or perform equivalent replacements for some of the technical features. Any equivalent structure directly or indirectly using the content of the specification and drawings of the present invention in other related technical fields shall be similarly within the scope of the patent protection of the present invention.

Claims

1. A method for online monitoring of voltage transformer metering performance, characterized in that: The following steps are involved: S10, collecting M groups of three-phase voltage transformer secondary side signals, the number of channels is N; S20, assuming that the analysis window is L, and performing standardization processing on it; S30, calculating the mean of the amplitude and phase after the standardization processing, and constructing the transformer measurement performance characterization quantity based on the transformer secondary side amplitude and phase data; S40, analyzing the voltage transformer metering performance of the N-channel, where the voltage transformer metering performance is divided into a normal state and an out-of-tolerance state; S50, identifying the metering performance status of each channel mutual inductor, and calculating a virtual standard for a normal mutual inductor according to the metering status; S60, calculating the ratio difference and angle difference of the N-channel voltage transformer.

2. A method for online monitoring of voltage transformer metering performance according to claim 1, characterized in that: In step S10, the amplitude signal is: ； in, , is the number of channels, M is the number of groups of three-phase voltage transformers, Superscript Indicates the time point, Indicates channels, i.e. Indicates aisle The amplitude of the moment; The phase signal is: ； in, Superscript Indicates the time point, Indicates channels, i.e. Indicates aisle The phase of the moment.

3. A method for online monitoring of voltage transformer metering performance according to claim 2, characterized in that: In step S20, the amplitude data is: ； The normalized amplitude data is: ； in, , ( , ), for The mean of for The variance of Similarly, the standardized phase data is: ； in, , ( , ), for The mean of for The variance of .

4. A method for online monitoring of voltage transformer metering performance according to claim 3, characterized in that: The specific steps of step S30 are as follows: S301, the mean values ​​of amplitude and phase are: ； ； in, for The mean of for The mean of S302, The metrological performance characterization quantities of each channel transformer are: ,in .

5. A method for online monitoring of voltage transformer metering performance according to claim 4, characterized in that: The specific steps of step S40 are as follows: S401, Randomly select 2 points as the initial cluster ; S402, calculate all sample points to distance and mark it as the closest cluster center category; S403, calculating the centers of the two category sample points in step S402 as new cluster centers; S404, repeating steps S402 to S403 until the cluster center no longer changes or the maximum number of iterations is reached; S405, finally get the cluster center , and the number of samples corresponding to the two cluster centers .

6. A method for online monitoring of voltage transformer metering performance according to claim 5, characterized in that: The specific steps of step S50 are as follows: S501. Since the number of transformers in the out-of-tolerance state is less than the number of normal transformers, when ,but The corresponding sample point is a normal transformer, otherwise The corresponding sample point is a normal mutual inductor; S502, Assumption The corresponding sample point is a normal transformer. The mean of all transformers in normal state is calculated to obtain the virtual standard ,in That is the standard value corresponding to the amplitude, That is the standard value corresponding to the amplitude.

7. A method for online monitoring of voltage transformer metering performance according to claim 6, characterized in that: In step S60: The channel voltage transformer ratio difference is: 。 8. A method for online monitoring of voltage transformer metering performance according to claim 6, characterized in that: In step S60: The angular difference of the channel voltage transformer is: 。 9. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

10. An electronic terminal, characterized in that: include: Processor and memory; The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the terminal executes the method according to any one of claims 1 to 8.

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