An accurate measurement method of static magnetic hysteresis curve of electromagnetic voltage transformer

Abstract

The application relates to a kind of accurate measurement methods of electromagnetic voltage transformer static magnetic hysteresis curve, belong to transformer class equipment parameter measurement and accurate modeling field.The method is measured accurately to the static magnetic hysteresis curve of PT by simple port test and data processing based on intelligent bionic algorithm.Compared with traditional method, the static magnetic hysteresis curve measured by the method is more accurate, and the influence of the complex conductor structure in PT on the measurement result can be excluded.At the same time, the application can be directly used for the PT equipment with complete structure, without splitting or destroying the PT.The measured static magnetic hysteresis curve is shown as "magnetic chain-current" curve.

Description

Technical Field

[0001] This invention belongs to the field of parameter measurement and accurate modeling of transformer equipment, and relates to an accurate measurement method for the static hysteresis curve of an electromagnetic voltage transformer. Background Technology

[0002] Accurate modeling of electromagnetic voltage transformers (PTs) is of great significance for power system operation and maintenance and ferroresonant simulation. Measuring the static hysteresis curve of a PT is crucial for describing its saturation, loss, and dynamic response characteristics. However, measuring the static hysteresis curve of a fully functional PT is extremely difficult. Without disrupting the PT's structure, the modeling parameters can only be measured through simple port tests: given input voltage – measured output current – ​​data analysis. In this case, the PT port current composition is complex, containing multiple active and reactive current components, making it unsuitable for direct measurement of the PT's static hysteresis.

[0003] Existing PT static hysteresis measurement techniques neglect the effects of stray capacitance in the windings and eddy current losses and additional losses in the core. These effects can impact the accuracy of hysteresis curve measurements, leading to significant errors. Therefore, a PT static hysteresis measurement method that simultaneously considers the influence of stray capacitance and dynamic losses is urgently needed to improve the accuracy of the measured results. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide an accurate method for measuring the static hysteresis curve of an electromagnetic voltage transformer (PT). Through simple port tests and data processing based on an intelligent biomimetic algorithm, the static hysteresis curve of the PT is accurately measured. Compared with traditional methods, this method yields a more accurate static hysteresis curve and can eliminate the influence of the complex internal conductor structure of the PT on the measurement results. Furthermore, this method can be directly applied to structurally intact PT devices without disassembling or damaging the PT. The measured static hysteresis curve is represented as a "magnetic flux linkage-current" curve.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] An accurate measurement method for the static hysteresis curve of an electromagnetic voltage transformer, specifically including the following steps:

[0007] S1: Connect the power supply to the secondary side port of the PT device and conduct multiple sets of no-load tests to ensure that the ratio of the effective value of the power supply voltage to the frequency is a constant value.

[0008] S2: Write the fitness function, at which point the distribution of stray capacitances C1, C2, and C in the current transformer will be determined. 12The values ​​of r1 and r2 (r1 and r2 are variables; for a PT that has already been manufactured, they are constants, but their values ​​are different for different PTs) are assumed to be certain values; for each set of tests, the waveform of the current i5 in the static hysteresis branch is calculated.

[0009] S3: Using an intelligent biomimetic algorithm (such as particle swarm optimization, genetic algorithm, or other derived algorithms), based on the fitness function written in step S2, apply the fitness function to C1, C2, and C... 12 Solve for the values ​​of r1 and r2;

[0010] S4: When the above five unknowns C1, C2, C... 12 Once the values ​​of r1 and r2 are determined, the accurate waveform of i5 can be obtained; by measuring the voltage u at the secondary side port of the PT device... in By integrating, the flux linkage φ can be obtained; then, by plotting i5 as the x-axis and φ as the y-axis, the static hysteresis curve of PT can be drawn.

[0011] Furthermore, in step S1, all the no-load tests were conducted at low frequencies.

[0012] Furthermore, in step S1, when conducting an unloaded test at low frequency, the leakage impedances Z1 and Z2 of the PT are ignored in the broadband equivalent circuit of the PT.

[0013] Furthermore, in step S1, R L1 To characterize the linear resistance of eddy current losses, R L2 To characterize the nonlinear resistance with irregular losses, we have:

[0014]

[0015] Where r1 and r2 are constants, their values ​​are related to the model of PT, and are considered unknowns; u L2 For R L2 The voltage across the terminals; Z1 and Z2 characterize the leakage impedance of the PT, C1, C2 and C 12 This represents the distribution of stray capacitance in the current transformer, where N1 and N2 are the number of turns in the primary and secondary windings, respectively, and we have:

[0016] N1:N2=k (2)

[0017] When conducting experiments at low frequencies, the results were obtained.

[0018]

[0019] Among them, i in This indicates the input current at the secondary side port of the PT device.

[0020] Furthermore, in step S2, the fitness function is written, specifically including: randomly selecting two sets of i5 waveforms, and recording the i5 measured in the two sets of experiments as i a with i b Then the formula for calculating fitness F is:

[0021]

[0022] Here, rms() means to find the effective value of the waveform within the parentheses; the closer the F value is to 0, the better the fitness, and the intelligent bionic algorithm will use this as a basis for parameter optimization.

[0023] The advantages of this invention are as follows: This invention uses an innovative, non-destructive testing method to accurately measure the static hysteresis curve of a PT (Potential Transmission Device), overcoming the shortcomings of traditional testing methods such as large measurement errors and strong coupling with the excitation frequency, and without damaging the complete structure of the PT. The required testing equipment and data processing flow are simple and conceptually clear. It is suitable for batch and automated testing processes.

[0024] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0026] Figure 1 This is the broadband equivalent circuit of the PT;

[0027] Figure 2 A schematic diagram of the circuit connection for connecting the power supply to the secondary side port of the PT device;

[0028] Figure 3 This is the broadband equivalent circuit of the PT when conducting experiments at low frequencies. Detailed Implementation

[0029] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0030] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures, and should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0031] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0032] Please see Figures 1-3 , Figure 1 For the broadband equivalent circuit of PT, such as Figure 1 As shown, R L1 To characterize the linear resistance of eddy current losses, R L2 To characterize a nonlinear resistor with irregular losses, we have:

[0033]

[0034] Where r1 and r2 are constants, their values ​​are related to the model of PT, and are considered unknowns; u L2 For R L2 The voltage across the terminals; Z1 and Z2 characterize the leakage impedance of the PT, C1, C2 and C 12 This represents the distribution of stray capacitance in the current transformer. N1 and N2 are the number of turns in the primary and secondary windings, respectively, and we have:

[0035] N1:N2=k (2)

[0036] like Figure 1 As shown, the PT has a relatively complex equivalent circuit structure, making it difficult to accurately measure its static hysteresis without damaging the PT structure.

[0037] Connect the power supply to the secondary side port of the PT device, such as Figure 2 As shown. Since the experiments involved in this invention are all conducted at low frequencies, at this time... Figure 2 The equivalent circuit can be simplified to Figure 3 We can obtain:

[0038]

[0039] Among them, i in This indicates the input current at the secondary side port of the PT device. in with i in These can be directly measured in the experiment. C1, C2, C 12 r1, r2 are unknowns. Through a combination of experimental testing and intelligent biomimetic algorithms, the above five unknowns are solved.

[0040] This invention provides an accurate method for measuring the static hysteresis curve of an electromagnetic voltage transformer, specifically including the following steps:

[0041] S1: In Figure 2 Based on the circuit connection, multiple sets of no-load tests were conducted to ensure that the ratio of the effective value of the power supply voltage to the frequency is a constant.

[0042] S2: Write the fitness function, where C1, C2, and C... 12 The values ​​of r1 and r2 are assumed to be certain values; for each group of experiments, the waveform of i5 is calculated.

[0043] The i5 measured in the two sets of experiments are denoted as i. a with i b Then the formula for calculating fitness F is:

[0044]

[0045] Here, rms() means to find the effective value of the waveform within the parentheses; the closer the F value is to 0, the better the fitness, and the intelligent bionic algorithm will use this as a basis for parameter optimization.

[0046] S3: Using intelligent biomimetic algorithms (such as particle swarm optimization, genetic algorithms, or other derived algorithms), based on the above fitness function, for C1, C2, and C... 12 Solve for the values ​​of r1 and r2;

[0047] S4: When the above five unknowns C1, C2, C... 12Once the values ​​of r1 and r2 are determined, the accurate waveform of i5 can be obtained. This is achieved by adjusting u... in By integrating, the flux linkage φ can be obtained; then, by plotting i5 as the x-axis and φ as the y-axis, the static hysteresis curve of PT can be drawn.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for accurately measuring the static hysteresis curve of an electromagnetic voltage transformer, characterized in that, The method specifically includes the following steps: S1: Connect the power supply to the secondary side port of the PT device and conduct multiple sets of no-load tests to ensure that the ratio of the effective value of the power supply voltage to the frequency is a constant value; where PT represents an electromagnetic voltage transformer. S2: Write the fitness function, at which point the distribution of stray capacitance in the current transformer will be considered. , , and variables , The numerical assumption is that it is a certain value; for each set of experiments, the current of the static hysteresis branch is calculated. The waveform; Writing the fitness function specifically includes: randomly selecting two groups The waveforms obtained from the two sets of experiments They are respectively denoted as and Then fitness The calculation formula is: （1） in, rms () indicates that the effective value of the waveform within the parentheses is calculated; the closer the F value is to 0, the better the fitness, and the intelligent bionic algorithm will use this as a basis for parameter optimization; S3: Using an intelligent biomimetic algorithm, based on the fitness function written in step S2, the fitness function is... , , , , Solve for the value of ; S4: When there are five unknowns , , , , Once the value is determined, it can be obtained. The accurate waveform; obtained by measuring the voltage at the secondary side port of the PT device. Integrating, we can obtain the magnetic flux. At this time, with As the x-axis, with Using the vertical axis as the ordinate, the static hysteresis curve of PT can be plotted.

2. The accurate measurement method for the static hysteresis curve of an electromagnetic voltage transformer according to claim 1, characterized in that, In step S1, all the no-load tests were conducted at low frequencies.

3. The accurate measurement method for the static hysteresis curve of an electromagnetic voltage transformer according to claim 2, characterized in that, In step S1, when conducting an unloaded test at low frequencies, the leakage impedance of the PT is ignored in the broadband equivalent circuit of the PT. and .

4. The accurate measurement method for the static hysteresis curve of an electromagnetic voltage transformer according to claim 3, characterized in that, In step S1, The linear resistance is used to characterize eddy current losses. To characterize the nonlinear resistance with irregular losses, we have: （2） in, and It is a constant, and its value is related to the model of PT, so it is considered an unknown quantity; for The voltage across the two ends; and Characterizing the leakage impedance of the PT, , and This indicates the distribution of stray capacitance in the current transformer. and Let be the number of turns of the winding on the primary side and the secondary side, respectively, and have: （3） When conducting experiments at low frequencies, the results were obtained. （4） in, This indicates the input current at the secondary side port of the PT device.

5. The method for accurately measuring the static hysteresis curve of an electromagnetic voltage transformer according to claim 1, characterized in that, In step S3, the intelligent bionic algorithm includes particle swarm optimization, genetic algorithm, or other derived algorithms.

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