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

Abstract

The present invention is applicable to the field of electric energy metering technology and relates to an online monitoring method, medium, and terminal for voltage transformer metering performance, including: S10, collecting M groups of three-phase voltage transformer secondary side signals, with the number of channels being N; S20, assuming an analysis window of L, performing standardization processing on the signals; S30, calculating the mean of the amplitude and phase after standardization processing, and constructing a transformer metering performance representation using the transformer secondary side amplitude and phase data; S40, analyzing the metering performance of the voltage transformer of N channels, and dividing the voltage transformer metering performance into a normal state and an out-of-tolerance state; S50, identifying the metering performance state of each channel transformer, and calculating a virtual standard for the normal transformer according to the metering state; S60, calculating the ratio difference and angular difference of the N-channel voltage transformer. The present invention uses the ratio and angular difference of the transformer as the metering performance of the transformer and analyzes them as a whole, thereby improving monitoring efficiency and identification accuracy.

Description

Technical Field

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

[0002] Capacitor Voltage Transformer (CVT) is widely used in high voltage applications due to its excellent insulation properties.

[0003] Patent publication number CN104155627A provides a method for detecting the error characteristics of an ultra-high voltage capacitor voltage transformer, including step 1: performing an offline on-site transformer handover test on the electromagnetic voltage transformer and correcting the electromagnetic voltage transformer based on the test results; step 2: using the corrected electromagnetic voltage transformer as a standard voltage transformer and performing online error detection on the capacitor voltage transformer using an online error detection device; the capacitor voltage transformer is connected to the transformer outgoing line and the high-voltage reactor outgoing line of the three-phase bus; and the electromagnetic voltage transformer is connected to the bus between the transformer and the high-voltage reactor. This patent also uses a corrected electromagnetic voltage transformer as the standard voltage transformer and compares it with the capacitor voltage transformer to be tested to ultimately obtain the error result. This solution is also unable to detect transformer errors under real-time operating conditions, and the monitoring results are biased.

[0004] Therefore, how to provide a method for monitoring the metering performance of a voltage transformer with high monitoring efficiency and identification accuracy is an urgent problem to be solved by people in this technical field. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method for online monitoring of the metering performance of a voltage transformer to solve the problems of low efficiency and recognition accuracy in the existing technology of monitoring the metering performance of a voltage transformer; in addition, the present invention also provides a medium and terminal for online monitoring of the metering performance of a voltage transformer.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

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

[0008] S10, collecting M groups of three-phase voltage transformer secondary side signals, the number of channels is N;

[0009] S20, assuming that the analysis window is L, perform standardization on it;

[0010] S30, calculating the average of the amplitude and phase after the normalization processing, and constructing the transformer measurement performance characterization quantity based on the transformer secondary side amplitude and phase signals;

[0011] S40, analyzing the voltage transformer metering performance of channel N, where the voltage transformer metering performance is divided into a normal state and an out-of-tolerance state;

[0012] 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;

[0013] S60: Calculate the ratio difference and angle difference of the N-channel voltage transformer.

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

[0015] ;

[0016] in, , is the number of channels, M is the number of groups of three-phase voltage transformers, superscript Indicates a point in time, Indicates the channels, i.e. Indicates the aisle Amplitude of the moment;

[0017] The phase signal is:

[0018] ;

[0019] in, superscript Indicates a point in time, Indicates the channels, i.e. Indicates the aisle The phase of the moment.

[0020] Furthermore, in step S20, the amplitude signal is:

[0021] ;

[0022] The normalized amplitude signal is:

[0023] ;

[0024] in, , ( , ), for The mean of for variance;

[0025] Similarly, the normalized phase signal is:

[0026] ;

[0027] in, , ( , ), for The mean of for The variance of .

[0028] Furthermore, the specific steps of step S30 are as follows:

[0029] S301, the mean values of amplitude and phase are:

[0030] ;

[0031] ;

[0032] in, for The mean of for The mean of

[0033] S302, The metrological performance characterization quantities of each channel mutual inductor are: ,in .

[0034] Furthermore, the specific steps of step S40 are as follows:

[0035] S401, in Randomly select 2 points as the initial cluster ;

[0036] S402, calculate all sample points to distance and mark it as the closest cluster center category;

[0037] S403, calculating the centers of the two categories of sample points in step S402 as new cluster centers;

[0038] S404, repeating steps S402 to S403 until the cluster center no longer changes or the maximum number of iterations is reached;

[0039] S405, finally get the cluster center , and the number of samples corresponding to the two cluster centers .

[0040] Furthermore, the specific steps of step S50 are as follows:

[0041] 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 mutual inductor, otherwise The corresponding sample point is a normal mutual inductor;

[0042] 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 phase.

[0043] Furthermore, in step S60:

[0044] The channel voltage transformer ratio difference is:

[0045] .

[0046] Furthermore, in step S60:

[0047] The angular difference of the channel voltage transformer is:

[0048] .

[0049] In a second aspect, the present invention further provides a computer-readable storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by a processor, the method described above is implemented.

[0050] In a third aspect, the present invention further provides an electronic terminal, comprising: 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 method described above.

[0051] Compared with the prior art, the method, medium, and terminal for online monitoring of voltage transformer metering performance provided by the present invention have at least the following beneficial effects:

[0052] The existing calibration method is offline calibration with power off. The same voltage signal is applied simultaneously to the transformer to be tested and a high-precision standard. The difference between the output value of the transformer to be tested and the output value of the standard is the static error of the transformer. This method has low monitoring efficiency and identification accuracy. The present invention has a simple process and convenient operation. By analyzing the secondary side (amplitude and phase) of the voltage transformer and calculating the angle difference based on the phase, the ratio difference and the angle difference are calculated completely independently. The ratio and angle difference of the transformer are used as the metrological performance of the transformer. The transformer is analyzed as a whole to identify the transformer with normal metrological performance, thereby obtaining a virtual transformer standard. Based on the virtual standard, the metrological error of the transformer in each channel is determined, achieving higher monitoring efficiency and identification accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the scheme of the present invention, a brief introduction is given below to the figures required for use in the description of the embodiments. Obviously, the figures described below are some embodiments of the present invention. For ordinary technicians in this field, other figures can be obtained based on these figures without paying any creative work.

[0054] Figure 1 The present invention provides a flowchart of a method for online monitoring of voltage transformer metering performance. DETAILED DESCRIPTION

[0055] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0057] The present invention provides a method for online monitoring of voltage transformer metering performance, which is applied to the real-time monitoring of error characteristics of a capacitor voltage transformer (CVT). The method comprises the following steps:

[0058] S10. Collect M groups of three-phase voltage transformer secondary side signals, with N channels; S20. Assume that the analysis window is L and perform standardization on them; S30. Calculate the mean of the amplitude and phase after standardization, and construct the transformer metrological performance characterization quantity with the transformer secondary side amplitude and phase signals; S40. Analyze the metrological performance of the voltage transformer of N channels, and divide the voltage transformer metrological performance into normal state and out-of-tolerance state; S50. Identify the metrological performance state of the transformer of each channel, and calculate the virtual standard for the normal transformer according to the metrological state; S60. Calculate the ratio difference and angle difference of the N-channel voltage transformer.

[0059] The present invention uses the ratio and the angular difference of the mutual inductor as the measurement performance of the mutual inductor and analyzes them as a whole, thereby improving the monitoring efficiency and identification accuracy.

[0060] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0061] The present invention provides an online monitoring method for the metering performance of a voltage transformer, which is applied to the real-time monitoring of the error characteristics of a capacitor voltage transformer (CVT). The actual conversion relationship between the primary voltage and the secondary voltage of the transformer is:

[0062] ;

[0063] in, 、 They are the measured values of the primary and secondary voltages of the voltage transformer, is the rated transformation ratio of the voltage transformer, is the error of the voltage transformer. As can be seen from the above formula, there is a linear relationship between the secondary side signal and the primary side signal of the voltage transformer. In the application scenario of 220kV and above voltage level, multiple groups of transformers connected under the same bus have the same primary side signal. 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 cluster analysis method to identify a few transformers with out-of-tolerance in the transformer cluster, such as Figure 1 As shown, in this embodiment, the method for online monitoring of voltage transformer metering performance includes the following steps:

[0064] S10. Collect M groups of three-phase voltage transformer secondary side signals, with N channels.

[0065] Specifically, in this embodiment, the amplitude signal is:

[0066] ;

[0067] in , is the number of channels, M is the number of groups of three-phase voltage transformers, superscript Indicates a point in time, Indicates the channels, i.e. Indicates the aisle Amplitude of moment.

[0068] The phase signal is:

[0069] ;

[0070] in, superscript Indicates a point in time, Indicates the channels. Indicates the aisle The phase of the moment.

[0071] S20, assuming the analysis window is L ( < ), and standardize it.

[0072] Specifically, in this embodiment, the amplitude signal is:

[0073] ;

[0074] The normalized amplitude data is:

[0075] ;

[0076] in , ( , ), for The mean of for The variance of .

[0077] Furthermore, in this embodiment, the normalized phase signal is similarly:

[0078] ;

[0079] in, , ( , ), for The mean of for The variance of .

[0080] S30. Calculate the average of the amplitude and phase after the normalization process, and construct a characterization of the transformer's metrological performance using the transformer's secondary side amplitude and phase signals.

[0081] Specifically, in this embodiment, the specific steps of step S30 are as follows:

[0082] S301, the mean values of amplitude and phase are:

[0083] ;

[0084] ;

[0085] in, for The mean of for The mean of .

[0086] S302, The metrological performance characterization quantities of each channel mutual inductor are: ,in .

[0087] S40. Analyze the metrological performance of the voltage transformers in the N channels. Voltage transformer metrological performance can be categorized into normal and out-of-tolerance states. Transformers in out-of-tolerance states account for a relatively small proportion, typically less than one-third. Therefore, cluster analysis is performed on the metrological performance indicators of the voltage transformers in the N channels. The number of clusters is set to two, dividing the voltage transformers in the N channels into two categories: normal and out-of-tolerance.

[0088] Specifically, in this embodiment, the specific steps of step S40 are as follows:

[0089] S401, in Randomly select 2 points as the initial cluster .

[0090] S402, calculate all sample points to distance and marks it as the closest cluster center category.

[0091] S403: Calculate the centers of the two categories of sample points in S402 as new cluster centers.

[0092] S404: Repeat steps S402 and S403 until the cluster center no longer changes or the maximum number of iterations is reached.

[0093] S405, finally get the cluster center , and the number of samples corresponding to the two cluster centers .

[0094] S50: Identify the metering performance status of each channel mutual inductor, and calculate a virtual standard for a normal mutual inductor according to the metering status.

[0095] Specifically, in this embodiment, the specific steps of step S50 are as follows:

[0096] S501, the number of transformers with abnormal tolerance is less than the normal number of transformers. ,but The corresponding sample point is a normal mutual inductor, otherwise The corresponding sample point is a normal transformer.

[0097] 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 phase.

[0098] S60: Calculate the ratio difference and angle difference of the N-channel voltage transformer.

[0099] Specifically, in this embodiment, The channel voltage transformer ratio difference is:

[0100] ;

[0101] Right now:

[0102] .

[0103] The angular difference of the channel voltage transformer is:

[0104] ;

[0105] Right now:

[0106] .

[0107] An embodiment of the present invention further 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 the embodiment is implemented.

[0108] An embodiment of the present invention further provides an electronic terminal, comprising: 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.

[0109] Regarding the computer-readable storage medium in this embodiment, those skilled in the art will appreciate that all or part of the steps in the aforementioned method embodiments can be implemented using hardware associated with the computer program. The aforementioned computer program can be stored in a computer-readable storage medium. When executed, the program performs the steps in the aforementioned method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0110] 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 computer programs, the communication interface is used for communication, and the processor and the transceiver are used to run computer programs so that the electronic terminal executes the various steps of the above method.

[0111] The online voltage transformer metrological performance monitoring method, medium, and terminal described in the above embodiments are different from the prior art. The existing calibration method is offline calibration with power off. The same voltage signal is applied simultaneously to the transformer to be tested and a high-precision standard. The difference between the output value of the transformer to be tested and the output value of the standard is the static error of the transformer. This method has low monitoring efficiency and identification accuracy. The present invention has a simple process and convenient operation. By analyzing the secondary side (amplitude and phase) of the voltage transformer and calculating the angular difference based on the phase, the ratio difference and the angular difference are calculated completely independently. The ratio and angular difference of the transformer are used as the metrological performance of the transformer. The transformer is analyzed as a whole to identify transformers with normal metrological performance, thereby obtaining a virtual transformer standard. Based on the virtual standard, the metrological error of each channel transformer is obtained, achieving higher monitoring efficiency and identification accuracy.

[0112] Obviously, the embodiments described above are only preferred embodiments of the present invention, rather than all embodiments. The preferred embodiments of the present invention are given in the accompanying 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 disclosure of the present invention more thorough and comprehensive. Although the present invention has been described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions described in the aforementioned specific embodiments, or to make equivalent replacements for some of the technical features therein. Any equivalent structure made using the contents of the present invention specification and drawings, directly or indirectly used in other related technical fields, is also within the scope of 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; 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 a point in time, Indicates the channels, i.e. Indicates the aisle Amplitude of the moment; The phase signal is: ； in, superscript Indicates a point in time, Indicates the channels, i.e. Indicates the aisle The phase of the moment; S20, assuming that the analysis window is L, perform standardization on it; In step S20, the amplitude signal is: ； The normalized amplitude signal is: ； in, , , , for The mean of for variance; Similarly, the normalized phase signal is: ； in, , , , for The mean of for variance; S30, calculating the average of the amplitude and phase after the normalization processing, and constructing the transformer measurement performance characterization quantity based on the transformer secondary side amplitude and phase signals; 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 mutual inductor are: ,in ; S40, analyzing the voltage transformer metering performance of channel N, where the voltage transformer metering performance is divided into a normal state and an out-of-tolerance state; The specific steps of step S40 are as follows: S401, in 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 categories of 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 ; 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; 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 mutual inductor, 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 phase; S60, calculating the ratio difference and angle difference of the N-channel voltage transformer; In step S60: The channel voltage transformer ratio difference is: ； The angular difference of the channel voltage transformer is: 。 2. 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 claim 1 is implemented.

3. 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 performs the method according to claim 1.

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