Method, device, equipment and storage medium for eliminating power grid harmonic voltage measurement errors

Abstract

The present application relates to a method and device for eliminating harmonic voltage measurement errors in a power grid. The method includes: obtaining the fundamental positive-sequence voltage and fundamental negative-sequence voltage corresponding to the three-phase line voltage of the power grid; determining the negative-sequence voltage imbalance and the positive-negative sequence voltage phase difference of the three-phase line voltage according to the fundamental positive-sequence voltage and the fundamental negative-sequence voltage; determining the three conversion coefficients corresponding to the three-phase line voltages according to the negative-sequence voltage imbalance, the positive-negative sequence voltage phase difference, and the preset negative-sequence voltage imbalance threshold; obtaining the harmonic data corresponding to the three-phase line voltages, and determining the harmonic data of the three-phase phase voltage of the power grid according to the harmonic data corresponding to the three-phase line voltages and the three conversion coefficients. Accurate harmonic data of the three-phase phase voltage can be obtained, and based on the harmonic data of the three-phase phase voltage, the power quality of the power grid can be accurately evaluated, so that the staff can accurately judge the power quality of the power grid, which is convenient for maintaining or optimizing the power grid.

Description

Technical Field

[0001] The present application relates to the technical field of power quality testing of power grids, and in particular to a method, device, equipment and storage medium for eliminating power grid harmonic voltage measurement errors. Background Art

[0002] With the development of power system technology, the scale of the power grid is getting larger and larger, and the number of nonlinear loads is growing explosively. Such as large rectifier equipment, variable frequency speed regulation equipment, electrified railway locomotives, arc furnaces, etc. These nonlinear loads will inject harmonic currents into the power grid, thereby causing grid voltage distortion, leading to problems with the power quality of the grid, and reducing the reliability of the power supply of the grid. On the other hand, with the rapid development of modern science and technology, users are increasingly using high-precision and cutting-edge power electronic equipment, and at the same time, a large number of tightly continuous process control systems are used to complete work processing and management. These all require high-quality and high-reliability power grids and corresponding power quality. The electromagnetic voltage transformer in the power grid is an important link between the primary system and the secondary system. In order to ensure safety, a harmonic elimination device needs to be installed to ensure the safe operation of the power grid. However, after the harmonic elimination device is installed, the excitation current dominated by the third zero-sequence harmonic will inevitably cause the displacement of the neutral point voltage when it flows through the harmonic elimination device connected in series on the neutral line of the electromagnetic voltage transformer, which will cause errors in the measurement of the harmonic voltage measured on the secondary side. The resulting harmonic voltage measurement error will directly affect the measurement results of the power quality, thereby bringing economic, management and technical risks, and reducing the expected benefits of the construction of the power quality online monitoring system and the universal measurement work on the improvement of the power quality management of the power grid. Therefore, how to accurately measure the harmonic voltage while ensuring the safety of the power grid operation is a problem that needs to be solved at present.

[0003] In traditional technology, in order to ensure that there is no error in the measurement of harmonic voltage, the error in harmonic voltage measurement is eliminated by removing the detuning device and directly grounding the neutral line of the electromagnetic voltage transformer to obtain accurate harmonic voltage measurement results.

[0004] However, from the perspective of ensuring the safe operation of electromagnetic voltage transformers, the larger the resistance of the damper (detuning device) that suppresses ferromagnetic resonance, the better the effect. Therefore, the traditional technology method, without the installation of a detuning device, makes the electromagnetic voltage transformer too risky during operation and prone to safety accidents. Summary of the invention

[0005] Based on this, it is necessary to provide a method, device, computer equipment and storage medium that can eliminate voltage harmonic measurement errors while ensuring the safety of power grid operation in response to the above technical problems.

[0006] A method for eliminating harmonic voltage measurement errors in a power grid, the power grid comprising an electromagnetic voltage transformer, a harmonic eliminator being arranged between the neutral point of the primary winding of the electromagnetic voltage transformer and the ground, the method comprising: obtaining a fundamental positive-sequence voltage and a fundamental negative-sequence voltage corresponding to the three-phase line voltage of the power grid; determining the negative-sequence voltage imbalance and the positive-negative sequence voltage phase difference of the three-phase line voltage according to the fundamental positive-sequence voltage and the fundamental negative-sequence voltage; determining three conversion coefficients corresponding to the three-phase line voltages according to the negative-sequence voltage imbalance, the positive-negative sequence voltage phase difference, and a preset negative-sequence voltage imbalance threshold; obtaining harmonic data corresponding to the three-phase line voltages, and determining the harmonic data of the three-phase phase voltage of the power grid according to the harmonic data corresponding to the three-phase line voltages and the three conversion coefficients.

[0007] In one embodiment, the obtaining of the fundamental positive-sequence voltage and the fundamental negative-sequence voltage corresponding to the three-phase line voltage of the power grid includes: obtaining the three-phase line voltage of the power grid, and determining the fundamental voltage amplitudes and fundamental voltage phases corresponding to the three-phase line voltages according to the three-phase line voltages, wherein the three-phase line voltages include the line voltage between phase A and phase B, the line voltage between phase B and phase C, and the line voltage between phase C and phase A; determining the fundamental positive-sequence voltage and the fundamental negative-sequence voltage corresponding to the three-phase line voltage according to the fundamental voltage amplitudes and fundamental voltage phases corresponding to the three-phase line voltages.

[0008] In one of the embodiments, determining the negative-sequence voltage imbalance and the positive-negative sequence voltage phase difference of the three-phase line voltage according to the fundamental positive-sequence voltage and the fundamental negative-sequence voltage includes: respectively acquiring the amplitude and phase of the fundamental positive-sequence voltage and the fundamental negative-sequence voltage; determining the negative-sequence voltage imbalance of the three-phase line voltage according to the amplitude of the fundamental positive-sequence voltage and the amplitude of the fundamental negative-sequence voltage; determining the positive-negative sequence voltage phase difference of the three-phase line voltage according to the phase of the fundamental positive-sequence voltage and the phase of the fundamental negative-sequence voltage.

[0009] In one embodiment, determining the three conversion coefficients corresponding to the three-phase line voltages respectively according to the negative sequence voltage imbalance, the positive and negative sequence voltage phase difference, and a preset negative sequence voltage imbalance threshold comprises: determining the three conversion coefficients corresponding to the three-phase line voltages respectively according to the following formula:

[0010]

[0011]

[0012]

[0013] Among them, α ABis the conversion coefficient of the line voltage between phase A and phase B in the three-phase line voltage, α BC is the conversion coefficient of the line voltage between phase B and phase C in the three-phase line voltage, α CA is the conversion coefficient of the line voltage between phase C and phase A in the three-phase line voltage, θ is the phase difference between the positive and negative sequence voltages corresponding to the three-phase line voltage, ε is the negative sequence voltage imbalance corresponding to the three-phase line voltage, and γ is the preset negative sequence voltage imbalance threshold.

[0014] In one embodiment, the harmonic data of the three-phase voltage includes the total harmonic distortion rate of the three-phase voltage and the content rate of each harmonic of the three-phase voltage, the harmonic data of the three-phase line voltage includes the total harmonic distortion rate of the three-phase line voltage and the content rate of each harmonic of the three-phase line voltage, and the obtaining of the harmonic data corresponding to the three-phase line voltages, and determining the harmonic data of the three-phase voltage of the power grid according to the harmonic data corresponding to the three-phase voltages and the three conversion coefficients, includes: determining the total harmonic distortion rate of the phase A voltage of the three-phase voltage of the power grid according to the total harmonic distortion rate and the conversion coefficient of the line voltage between phases A and B of the power grid; determining the total harmonic distortion rate of the phase A voltage of the three-phase voltage of the power grid according to the total harmonic distortion rate and the conversion coefficient of the line voltage between phases B and C of the power grid. The invention relates to a method for determining the total harmonic distortion rate of the phase B voltage among the three-phase phase voltages of the power grid; determining the total harmonic distortion rate of the phase C voltage among the three-phase phase voltages of the power grid according to the total harmonic distortion rate and conversion coefficient of the line voltage between phases C and phases A of the power grid; determining the content rate of each harmonic of the phase A voltage among the three-phase phase voltages of the power grid according to the content rate of each harmonic of the line voltage between phases A and phases B of the power grid and the conversion coefficient; determining the content rate of each harmonic of the phase B voltage among the three-phase phase voltages of the power grid according to the content rate of each harmonic of the line voltage between phases B and phases C of the power grid and the conversion coefficient; determining the content rate of each harmonic of the phase C voltage among the three-phase phase voltages of the power grid according to the content rate of each harmonic of the line voltage between phases C and phases A of the power grid and the conversion coefficient.

[0015] In one of the embodiments, after obtaining the three-phase line voltage of the power grid, the method further includes: synthesizing the obtained three-phase line voltage to obtain a complete three-phase line voltage of the power grid; adjusting the phase sequence of the three-phase line voltage so that the phase sequence of the three-phase line voltage is a positive sequence.

[0016] A device for eliminating harmonic voltage measurement errors in a power grid, the power grid comprising an electromagnetic voltage transformer, a harmonic eliminator being arranged between a neutral point of a primary winding of the electromagnetic voltage transformer and ground, the device comprising:

[0017] A voltage fundamental wave determination module, used for obtaining a fundamental wave positive-sequence voltage and a fundamental wave negative-sequence voltage corresponding to the three-phase line voltage of the power grid;

[0018] A voltage parameter determination module, used to determine the negative sequence voltage imbalance and the positive and negative sequence voltage phase difference of the three-phase line voltage according to the fundamental positive sequence voltage and the fundamental negative sequence voltage;

[0019] A conversion coefficient determination module, used to determine three conversion coefficients corresponding to the three-phase line voltages respectively according to the negative sequence voltage imbalance, the positive and negative sequence voltage phase difference, and a preset negative sequence voltage imbalance threshold;

[0020] The voltage harmonic determination module is used to obtain the harmonic data corresponding to the three-phase line voltages respectively, and determine the harmonic data of the three-phase phase voltages of the power grid according to the harmonic data corresponding to the three-phase line voltages respectively and the three conversion coefficients.

[0021] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the following steps when executing the computer program: obtaining a fundamental positive-sequence voltage and a fundamental negative-sequence voltage corresponding to the three-phase line voltage of the power grid; determining the negative-sequence voltage imbalance and the positive-negative sequence voltage phase difference of the three-phase line voltage according to the fundamental positive-sequence voltage and the fundamental negative-sequence voltage; determining three conversion coefficients corresponding to the three-phase line voltages according to the negative-sequence voltage imbalance, the positive-negative sequence voltage phase difference, and a preset negative-sequence voltage imbalance threshold; obtaining harmonic data corresponding to the three-phase line voltages, and determining the harmonic data of the three-phase phase voltage of the power grid according to the harmonic data corresponding to the three-phase line voltages and the three conversion coefficients.

[0022] A computer-readable storage medium stores a computer program, which implements the following steps when executed by a processor: obtaining a fundamental positive-sequence voltage and a fundamental negative-sequence voltage corresponding to the three-phase line voltage of the power grid; determining the negative-sequence voltage imbalance and the positive-negative sequence voltage phase difference of the three-phase line voltage according to the fundamental positive-sequence voltage and the fundamental negative-sequence voltage; determining three conversion coefficients corresponding to the three-phase line voltages according to the negative-sequence voltage imbalance, the positive-negative sequence voltage phase difference, and a preset negative-sequence voltage imbalance threshold; obtaining harmonic data corresponding to the three-phase line voltages, and determining the harmonic data of the three-phase phase voltage of the power grid according to the harmonic data corresponding to the three-phase line voltages and the three conversion coefficients.

[0023] A computer program product. The computer program product includes a computer program, which implements the following steps when executed by a processor: obtaining a fundamental positive-sequence voltage and a fundamental negative-sequence voltage corresponding to the three-phase line voltage of the power grid; determining the negative-sequence voltage imbalance and the positive-negative sequence voltage phase difference of the three-phase line voltage according to the fundamental positive-sequence voltage and the fundamental negative-sequence voltage; determining three conversion coefficients corresponding to the three-phase line voltages according to the negative-sequence voltage imbalance, the positive-negative sequence voltage phase difference, and a preset negative-sequence voltage imbalance threshold; obtaining harmonic data corresponding to the three-phase line voltages, and determining the harmonic data of the three-phase phase voltage of the power grid according to the harmonic data corresponding to the three-phase line voltages and the three conversion coefficients.

[0024] The above-mentioned method, device, equipment and storage medium for eliminating the measurement error of harmonic voltage of the power grid. The power grid includes an electromagnetic voltage transformer, and a detuning device is arranged between the neutral point of the primary winding of the electromagnetic voltage transformer and the ground. Thus, by arranging the detuning device, the resonant overvoltage generated by the electromagnetic voltage transformer during operation is suppressed, thereby ensuring the safe operation of the power grid. By obtaining the fundamental positive sequence voltage and fundamental negative sequence voltage corresponding to the three-phase line voltage of the power grid, the reference voltage data of the power grid is obtained. After the electromagnetic voltage transformer is equipped with a detuning device, the neutral point voltage will be displaced, thereby causing an error in the phase voltage of the power grid, while the line voltage of the power grid will not produce an error due to this factor and is still accurate. Therefore, the fundamental voltage of the power grid is determined by the line voltage of the power grid, and an accurate fundamental voltage of the power grid can be obtained. Then, according to the positive sequence fundamental voltage and fundamental negative sequence voltage of the power grid, the negative sequence voltage imbalance and the positive and negative sequence voltage phase difference corresponding to the three-phase line voltage can be calculated. Then, the three conversion coefficients corresponding to the three-phase line voltages are calculated by the negative sequence voltage imbalance, the positive and negative sequence voltage phase difference, and the preset negative sequence voltage imbalance threshold, wherein the preset negative sequence voltage imbalance threshold is determined according to the national standard of the measuring instrument. Then, by obtaining the measurement data, the harmonic data corresponding to the three-phase line voltages are obtained, and then, according to the three conversion coefficients corresponding to the three-phase line voltages, the harmonic data corresponding to the three-phase line voltages are converted into the harmonic data of the three-phase phase voltage of the power grid, so that accurate harmonic data of the three-phase phase voltage can be obtained. Through the method of the present application, under the condition that the safe operation of the power grid is ensured by installing a harmonic elimination device, accurate harmonic data of the three-phase phase voltage can be obtained, so that the power quality of the power grid can be accurately evaluated based on the harmonic data of the three-phase phase voltage, and the errors in the traditional measurement method are eliminated, so that the staff can accurately judge the power quality of the power grid, which is convenient for the maintenance or optimization of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 is a flow chart of a method for eliminating power grid harmonic voltage measurement errors in one embodiment;

[0027] Figure 2 A schematic diagram of the angle connection of the measuring instrument corresponding to the neutral line string detuning electromagnetic voltage transformer in one embodiment;

[0028] Figure 3 A schematic diagram of a star connection of a measuring instrument corresponding to a neutral line directly grounded electromagnetic voltage transformer in another embodiment;

[0029] Figure 4 A flow chart of a method for determining a fundamental positive-sequence voltage and a fundamental negative-sequence voltage of a three-phase line voltage in one embodiment;

[0030] Figure 5 A schematic diagram of three-phase line voltage synthesis and phase sequence adjustment in one embodiment;

[0031] Figure 6 is a flow chart of a method for determining parameters of a three-phase line voltage in one embodiment;

[0032] Figure 7 A flowchart of a method for determining harmonic data conversion coefficients of three-phase line voltages and three-phase phase voltages in one embodiment;

[0033] Figure 8 A schematic diagram of test wiring in one embodiment;

[0034] Fig. 9 A structural diagram of a device for eliminating harmonic voltage measurement errors in a power grid in one embodiment;

[0035] Fig.10 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0036] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application 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 disclosure of the present application more thorough and comprehensive.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0038] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof.

[0039] As described in the background technology, the existing method of obtaining grid harmonics has the problem of not being able to take into account both the safety of the grid and the accuracy of the grid harmonics. The inventors have found that the reason for this problem is that if the safe operation of the grid is to be ensured, a detuning device needs to be set between the neutral point of the primary winding of the voltage transformer of the grid and the ground, but the setting of the detuning device will lead to inaccurate measured grid voltage harmonics.

[0040] Based on the above reasons, the present invention provides a method, device, equipment and storage medium for eliminating harmonic voltage measurement errors in a power grid, which can eliminate harmonic voltage measurement errors while ensuring the safety of the power grid during operation.

[0041] In one embodiment, Figure 1 As shown, a method for eliminating harmonic voltage measurement errors in a power grid is provided. The method is applicable to Figure 2 As shown in the figure, the electromagnetic voltage transformer 30 adopts the star connection method, and the power quality analyzer 40 adopts the delta connection method. The electromagnetic voltage transformer is a three-phase four-wire system. A detuning device 10 is arranged between the neutral point of the primary winding 20 of the electromagnetic voltage transformer and the ground. The secondary winding output a, b, c three-phase terminals of the electromagnetic voltage transformer 30 are connected to the A, B, C three-phase input terminals of the power quality analyzer 40. The N terminal and the B terminal of the power quality analyzer 40 are short-circuited. The secondary winding output n (neutral line) terminal of the electromagnetic voltage transformer is suspended. The terminal of the secondary winding 30 of the electromagnetic voltage transformer is connected to the power quality analyzer 40. The line voltage between phase A and phase B and the line voltage between phase B and phase C can be measured by the power quality analyzer. Figure 3In the transformer wiring situation shown, the neutral line of the primary winding 20 of the electromagnetic voltage transformer is grounded, and the star connection is adopted. The power quality analyzer 40 adopts the star connection. The a, b, c, and n terminals of the output end of the secondary winding 30 of the electromagnetic voltage transformer correspond to the A, B, C, and N terminals of the power quality analyzer 40 respectively. No detuning device is connected in series, so the safety is not high. The power grid of the present application includes an electromagnetic voltage transformer, and a detuning device is arranged between the neutral point of the primary winding of the electromagnetic voltage transformer and the ground. The method includes:

[0042] Step S100, obtaining a fundamental positive-sequence voltage and a fundamental negative-sequence voltage corresponding to a three-phase line voltage of a power grid.

[0043] Specifically, an electromagnetic voltage transformer is a voltage transformer that converts a primary voltage into a secondary voltage in proportion through electromagnetic induction, without any other electrical components (such as capacitors) that change the primary voltage.

[0044] Specifically, the positive sequence in the power grid is that phase A leads phase B by 120°, phase B leads phase C by 120°, and phase C leads phase A by 120°. The negative sequence in the power grid is that phase A lags phase B by 120°, phase B lags phase C by 120°, and phase C lags phase A by 120°. The component signal with the same frequency as the power frequency obtained by Fourier series decomposition of the periodic AC signal is called the fundamental signal.

[0045] Step S120, determining the negative sequence voltage imbalance and the positive and negative sequence voltage phase difference of the three-phase line voltage according to the fundamental positive sequence voltage and the fundamental negative sequence voltage.

[0046] Specifically, due to asymmetric faults, asymmetric line impedance, or unbalanced loads in the power grid, the power grid may have a three-phase imbalance problem. The imbalance of the three-phase voltage can reflect the degree of the three-phase imbalance.

[0047] Step S140, determining three conversion coefficients corresponding to the three-phase line voltages respectively according to the negative sequence voltage imbalance, the positive and negative sequence voltage phase difference, and a preset negative sequence voltage imbalance threshold.

[0048] Specifically, after the electromagnetic voltage transformer of the power grid is equipped with a harmonic elimination device, the neutral point voltage will be displaced, resulting in errors in the phase voltage of the power grid. However, the line voltage of the power grid will not have errors due to this factor and will remain accurate. Therefore, by measuring the line voltage and then converting it into the phase voltage through the conversion coefficient, an accurate phase voltage result can be obtained.

[0049] Step S160, obtaining harmonic data corresponding to the three-phase line voltages, and determining the harmonic data of the three-phase phase voltages of the power grid according to the harmonic data corresponding to the three-phase line voltages and three conversion coefficients.

[0050] Specifically, the harmonic data of the three-phase phase voltage includes the total harmonic distortion rate of the three-phase phase voltage and the content rate of each harmonic of the three-phase phase voltage, and the harmonic data of the three-phase line voltage includes the total harmonic distortion rate of the three-phase line voltage and the content rate of each harmonic of the three-phase line voltage. According to the provisions of the national standard "GBT 14549-1993 Power Quality Public Grid Harmonics", the industry uses phase voltage as an indicator for evaluating power quality. If line voltage is used, the measurement results cannot be compared horizontally, and the meaning of this indicator will be lost. In addition, the limit values ​​given by the standard are also based on phase voltage. Therefore, it is impossible to use the harmonic data of line voltage to evaluate the power quality of the power grid. It must be converted into harmonic data of phase voltage through a conversion coefficient before it can be used to evaluate the power quality of the power grid.

[0051] In this embodiment, the power grid includes an electromagnetic voltage transformer, and a detuning device is provided between the neutral point of the primary winding of the electromagnetic voltage transformer and the ground, so that by providing the detuning device, the resonant overvoltage generated by the electromagnetic voltage transformer during operation is suppressed, thereby ensuring the safe operation of the power grid. The fundamental positive-sequence voltage and fundamental negative-sequence voltage corresponding to the three-phase line voltage of the power grid are obtained. After the electromagnetic voltage transformer is equipped with the detuning device, the neutral point voltage will be displaced, thereby causing an error in the phase voltage of the power grid, while the line voltage of the power grid will not cause an error due to this factor and is still accurate. Then, according to the positive-sequence fundamental voltage and the fundamental negative-sequence voltage of the power grid, the negative-sequence voltage imbalance and the positive-negative-sequence voltage phase difference corresponding to the three-phase line voltage can be calculated, thereby determining the degree of error generated by the power grid due to the influence of the detuning device. Then, through the negative-sequence voltage imbalance, the positive-negative-sequence voltage phase difference, and the preset negative-sequence voltage imbalance threshold, the three conversion coefficients corresponding to the three-phase line voltages are calculated, wherein the preset negative-sequence voltage imbalance threshold is determined according to the national standard of the measuring instrument. Then, the harmonic data corresponding to the three-phase line voltages are obtained, and then the harmonic data corresponding to the three-phase line voltages are converted into the harmonic data of the three-phase phase voltage of the power grid according to the three conversion coefficients corresponding to the three-phase line voltages, so that accurate harmonic data of the three-phase phase voltage can be obtained. Through the method of the present application, accurate harmonic data of the three-phase phase voltage can be obtained while ensuring the safe operation of the power grid by installing a harmonic eliminator, so that the power quality of the power grid can be accurately evaluated based on the harmonic data of the three-phase phase voltage, eliminating the errors in the traditional measurement method, so that the staff can accurately judge the power quality of the power grid, which is convenient for the maintenance or optimization of the power grid.

[0052] In one embodiment, Figure 4 As shown, step S100 includes:

[0053] Step S400, obtaining the three-phase line voltage of the power grid, and determining the fundamental voltage amplitude and fundamental voltage phase corresponding to the three-phase line voltage respectively according to the three-phase line voltage.

[0054] Specifically, Figure 2 As shown, the three-phase line voltage includes the line voltage between phase A and phase B, the line voltage between phase B and phase C, and the line voltage between phase C and phase A.

[0055] Step S420, determining the fundamental positive sequence voltage and the fundamental negative sequence voltage corresponding to the three-phase line voltage according to the fundamental voltage amplitudes and fundamental voltage phases respectively corresponding to the three-phase line voltages.

[0056] Specifically, the fundamental positive-sequence voltage and fundamental negative-sequence voltage corresponding to the three-phase line voltage are determined by the following formula:

[0057]

[0058] in, is the fundamental positive sequence voltage corresponding to the three-phase line voltage, is the fundamental negative sequence voltage corresponding to the three-phase line voltage, U AB,1 U is the fundamental voltage amplitude of the line voltage between phase A and phase B in the three-phase line voltage. BC,1 is the fundamental voltage amplitude of the line voltage between phases B and C in the three-phase line voltage, U CA,1 is the fundamental voltage amplitude of the line voltage between phase C and phase A in the three-phase line voltage, δ AB,1 is the fundamental voltage phase of the line voltage between phase A and phase B in the three-phase line voltage, δ BC,1 is the fundamental voltage phase of the line voltage between phases B and C in the three-phase line voltage, δ CA,1 It is the fundamental voltage phase of the line voltage between phase C and phase A in the three-phase line voltage.

[0059] In this embodiment, the three-phase line voltage of the power grid is obtained by means of a power quality analyzer and voltage synthesis, and then the corresponding fundamental voltage amplitude and fundamental voltage phase are determined according to the three-phase line voltage, and then the fundamental positive-sequence voltage and fundamental negative-sequence voltage corresponding to the three-phase line voltage are calculated according to the fundamental voltage amplitude and phase, so as to facilitate subsequent calculations.

[0060] In one embodiment, after step S400, the method further includes:

[0061] Step S500: synthesize the acquired three-phase line voltages to obtain a complete three-phase line voltage of the power grid.

[0062] For example, Figure 2As shown, the electromagnetic voltage transformer 30 adopts a star connection method, the power quality analyzer 40 adopts a delta connection method, a detuning device 10 is provided between the neutral point of the primary winding 20 of the electromagnetic voltage transformer and the ground, and the terminal of the secondary winding 30 of the electromagnetic voltage transformer is connected to the power quality analyzer 40. The power quality analyzer can measure the line voltage between the A phase and the B phase and the line voltage between the B phase and the C phase, and then synthesize the line voltage between the C phase and the A phase through the following formula:

[0063] u CA (t) = u CB (t)-u AB (t)

[0064] Among them, u AB (t) is the line voltage between phase A and phase B, u BC (t) is the line voltage between phase B and phase C, u CA (t) is the line voltage between phase C and phase A.

[0065] Step S520, adjusting the phase sequence of the three-phase line voltage so that the three-phase line voltage is a positive sequence, and then performing a fast Fourier transform on the sampled three-phase line voltage to obtain three fundamental wave voltage amplitudes and three fundamental wave voltage phases corresponding to the three-phase line voltage.

[0066] Specifically, when the three-phase line voltage is in positive sequence, the line voltage between phases A and B leads the line voltage between phases B and C by 120°, the line voltage between phases B and C leads the line voltage between phases C and A by 120°, and the line voltage between phases C and A leads the line voltage between phases A and B by 120°. Therefore, if the measured phase sequence of the line voltage is not positive sequence, the phase sequence is adjusted by taking a negative number so that the phase sequence of the three-phase line voltage is positive sequence.

[0067] For example, Figure 5 As shown, the line voltage u between phase B and phase A is measured. AB (t), the line voltage U between phase B and phase C CB (), the line voltage u between phase C and phase A is synthesized AC (), in order to make the line voltage between phases B and C form a positive sequence with the line voltages of the other two phases, it is necessary to CB () Take a negative number to adjust the direction.

[0068] In this embodiment, the direction of the three-phase line voltage is adjusted so that the phase sequence of the three-phase line voltage is a positive sequence, which facilitates subsequent calculations.

[0069] In one embodiment, Figure 6 As shown, step S120 includes:

[0070] Step S600, respectively obtaining the amplitude and phase of the fundamental positive sequence voltage and the fundamental negative sequence voltage.

[0071] Specifically, the amplitude and phase of the fundamental positive sequence voltage corresponding to the three-phase line voltage are determined by the following formula:

[0072]

[0073] Among them, U Lp is the amplitude of the fundamental positive sequence voltage corresponding to the three-phase line voltage, is the phase of the fundamental positive sequence voltage corresponding to the three-phase line voltage, It is the fundamental positive sequence voltage corresponding to the three-phase line voltage.

[0074] The amplitude and phase of the fundamental negative sequence voltage corresponding to the three-phase line voltage are determined by the following formula:

[0075]

[0076] Among them, U Ln is the amplitude of the fundamental negative sequence voltage corresponding to the three-phase line voltage, is the phase of the fundamental negative sequence voltage corresponding to the three-phase line voltage, It is the fundamental negative sequence voltage corresponding to the three-phase line voltage.

[0077] Step S620, determining the negative sequence voltage imbalance of the three-phase line voltage according to the amplitude of the fundamental positive sequence voltage and the amplitude of the fundamental negative sequence voltage.

[0078] Specifically, the negative sequence voltage unbalance of the three-phase line voltage is determined by the following formula:

[0079]

[0080] Among them, ε is the negative sequence voltage unbalance corresponding to the three-phase line voltage, U Ln is the amplitude of the fundamental negative sequence voltage corresponding to the three-phase line voltage, U Lp It is the amplitude of the fundamental positive sequence voltage corresponding to the three-phase line voltage.

[0081] Step S640, determining the positive-sequence voltage phase difference of the three-phase line voltage according to the phase of the fundamental positive-sequence voltage and the phase of the fundamental negative-sequence voltage.

[0082] Specifically, the positive and negative sequence voltage phase difference corresponding to the three-phase line voltage is determined by the following formula:

[0083]

[0084] Among them, θ is the phase difference between the positive and negative sequence voltages corresponding to the three-phase line voltages, is the phase of the fundamental positive sequence voltage corresponding to the three-phase line voltage, It is the phase of the fundamental negative sequence voltage corresponding to the three-phase line voltage.

[0085] In this embodiment, the fundamental wave voltage parameters in the power grid are obtained by extracting the amplitude and phase of the fundamental wave positive sequence voltage and the amplitude and phase of the fundamental wave negative sequence voltage. Then, the negative sequence voltage imbalance of the power grid can be determined according to the amplitudes of the fundamental wave positive sequence voltage and the fundamental wave negative sequence voltage in the power grid. Then, the phase difference between the positive and negative sequence voltages in the power grid is determined according to the phases of the fundamental wave positive sequence voltage and the fundamental wave negative sequence voltage in the power grid.

[0086] In one embodiment, step S140 includes:

[0087] The three conversion coefficients corresponding to the three-phase line voltages are determined by the following formula:

[0088]

[0089]

[0090]

[0091] Among them, α AB is the conversion coefficient of the line voltage between phase A and phase B in the three-phase line voltage, α BC is the conversion coefficient of the line voltage between phase B and phase C in the three-phase line voltage, α CA is the conversion coefficient of the line voltage between phase C and phase A in the three-phase line voltage, θ is the phase difference between the positive and negative sequence voltages corresponding to the three-phase line voltage, ε is the negative sequence voltage imbalance corresponding to the three-phase line voltage, and γ is the preset negative sequence voltage imbalance threshold.

[0092] Specifically, the preset negative-sequence voltage imbalance threshold γ is determined according to the accuracy level of the measuring instrument, with reference to the provisions of the national standard "GBT 19862-2016 General Requirements for Power Quality Monitoring Equipment": The maximum allowable error of negative-sequence voltage imbalance measurement for Class A instruments is γ = ± 0.15%; The maximum allowable error of negative-sequence voltage imbalance measurement for Class S instruments is γ = ± 0.2%.

[0093] In this embodiment, according to the accuracy requirements of the measuring instrument, the negative sequence voltage imbalance threshold is determined, and then the value formulas of the three conversion coefficients corresponding to the three-phase line voltage are determined according to the negative sequence voltage imbalance threshold, and then the three conversion coefficients corresponding to the three-phase line voltage are calculated according to the positive and negative sequence voltage phase difference and negative sequence voltage imbalance of the power grid. Thus, a formula capable of converting the three-phase line voltage harmonic measurement parameters and the three-phase phase voltage harmonic measurement parameters is constructed. The conversion of the harmonic measurement results between the three-phase line voltage and the three-phase phase voltage is realized.

[0094] In one embodiment, the harmonic data of the three-phase phase voltage includes the total harmonic distortion rate of the three-phase phase voltage and the harmonic content rate of each order of the three-phase phase voltage, and the harmonic data of the three-phase line voltage includes the total harmonic distortion rate of the three-phase line voltage and the harmonic content rate of each order of the three-phase line voltage, such as Figure 7 As shown, step S160 includes:

[0095] Step S700, determining the total harmonic distortion rate of the phase voltage of phase A among the three-phase phase voltages of the power grid according to the total harmonic distortion rate and the conversion coefficient of the line voltage between phase A and phase B of the power grid.

[0096] Specifically, the harmonic data of the three-phase line voltage is measured by a power quality analyzer, which performs fast Fourier transform on three three-phase line voltage sampling data at a time interval of 10 cycles to obtain harmonics.

[0097] Harmonics refer to the sinusoidal components whose frequencies are integer multiples of the fundamental frequency greater than 1, obtained by Fourier series decomposition of periodic alternating current. The evaluation indicators of harmonics in the power grid include the harmonic ratio (HR) of the voltage and the total harmonic distortion (THD) of the voltage. The calculation formula for the harmonic ratio of the voltage is as follows:

[0098]

[0099] Among them, HRU(h) is the harmonic content rate of the grid voltage, U h is the root mean square value of the hth harmonic voltage of the power grid, U 1 is the root mean square value of the fundamental voltage of the power grid.

[0100] The calculation formula of voltage total harmonic distortion is as follows:

[0101]

[0102] Among them, THD U is the total harmonic distortion rate of the power grid voltage, U h is the voltage of the hth harmonic of the power grid, U 1 is the root mean square value of the fundamental voltage of the power grid, h=2, 3,…, N, N is the highest order of the harmonic considered.

[0103] Step S720, determining the total harmonic distortion rate of the phase B voltage among the three-phase phase voltages of the power grid according to the total harmonic distortion rate and the conversion coefficient of the line voltage between the phases B and C of the power grid.

[0104] Step S740, determining the total harmonic distortion rate of the phase voltage of phase C among the three-phase phase voltages of the power grid according to the total harmonic distortion rate and the conversion coefficient of the line voltage between phase C and phase A of the power grid.

[0105] Step S760, determining the harmonic content of the phase A voltage in the three-phase phase voltage of the power grid according to the harmonic content and conversion coefficient of the line voltage between the phase A and phase B of the power grid.

[0106] Step S780, determining the harmonic content of the phase B voltage among the three-phase phase voltages of the power grid according to the harmonic content and conversion coefficient of the line voltage between the phases B and C of the power grid.

[0107] Step S800, determining the harmonic content of the phase voltage of phase C in the three-phase phase voltage of the power grid according to the harmonic content and conversion coefficient of the line voltage between phase C and phase A of the power grid.

[0108] Specifically, the total harmonic distortion rate of the three-phase voltage of the power grid is determined by the following formula:

[0109]

[0110] in, is the total harmonic distortion rate of phase A voltage in the three-phase phase voltage of the power grid, is the total harmonic distortion rate of the B-phase voltage in the three-phase voltage of the power grid, is the total harmonic distortion rate of the C phase voltage in the three-phase phase voltage of the power grid, is the total harmonic distortion rate of the line voltage between phase A and phase B of the power grid, is the total harmonic distortion rate of the line voltage between phases B and C of the power grid, is the total harmonic distortion rate of the line voltage between phase C and phase A of the power grid;

[0111] The harmonic content of the three-phase voltage of the power grid is determined by the following formula:

[0112]

[0113] Among them, HRU (h) A HRU(h) is the harmonic content rate of phase A voltage in the three-phase voltage of the power grid. B HRU(h) is the harmonic content rate of the B phase voltage in the three-phase phase voltage of the power grid. C HRU(h) is the harmonic content rate of the C phase voltage in the three-phase phase voltage of the power grid. AB HRU(h) is the harmonic content of the line voltage between phase A and phase B of the power grid. BC HRU(h) is the harmonic content of the line voltage between phases B and C of the power grid. CA It is the harmonic content rate of the line voltage between phase C and phase A of the power grid.

[0114] Specifically, according to the national standard "GBT 14549-1993 Power Quality Public Grid Harmonics", the industry uses phase voltage as an indicator for evaluating power quality. If line voltage is used, the measurement results cannot be compared horizontally, and the meaning of this indicator will be lost. In addition, the limit value given by the standard is also based on phase voltage. Therefore, it is impossible to use the harmonic data of line voltage to evaluate the power quality of the power grid. It must be converted into harmonic data of phase voltage before it can be used to evaluate the power quality of the power grid.

[0115] In this embodiment, the harmonic data corresponding to the three-phase line voltage is converted into the harmonic data of the three-phase phase voltage through the conversion coefficient. Since the harmonic data of the three-phase line voltage is an accurate value, the accurate harmonic data of the three-phase phase voltage is obtained, so that the power quality of the power grid can be accurately analyzed through the harmonic data of the three-phase phase voltage. It is possible to judge whether the power quality of the power grid meets the standard according to whether the harmonic data of the three-phase phase voltage is greater than the prescribed preset value. If it is judged that it does not meet the standard, the power grid can be governed by means of harmonic compensation and the like. This enables the staff to accurately judge the power quality of the power grid, which is convenient for the maintenance or optimization of the power grid.

[0116] For example, Figure 8 As shown, the 10kV bus of a 110kV substation is taken as the monitoring object. The bus contains two sets of electromagnetic voltage transformers (hereinafter referred to as PT) using a three-phase four-wire connection method, named bus PT1 and line PT2 respectively. Through on-site material information query, the neutral point of the primary winding of bus PT1 is connected to the ground after the series detuning device R0, and the neutral point of the primary winding of line PT2 is directly grounded. Three measuring instruments of the same model with an accuracy level of A are selected to obtain secondary signals from the bus and line PT respectively, and perform synchronous measurements, wherein measuring instrument 1 is connected to bus PT1 in an angular manner (using the above embodiment). Figure 2 The wiring method shown in the figure), measuring instrument 2 is connected to bus PT1 in a star manner (there is a measurement error), and measuring instrument 3 is connected to line PT2 in a star manner (no measurement error). The final measurement results of the three measuring instruments are shown in Table 1, which verifies the accuracy of the three-phase voltage calculated by the method of the present application by means of an experiment in practice.

[0117] Taking a 10-cycle data segment as the analysis object, the negative sequence voltage imbalance ε=1.47% and the positive and negative sequence voltage phase difference θ=63.7° are calculated. It is not difficult to find that at this time ε>|γ|=0.15%, and the line-to-phase voltage conversion coefficient of the three-phase harmonic parameters is calculated. Then the harmonic data of the three-phase line voltage and the three-phase phase voltage are calculated.

[0118] As shown in Table 1.

[0119]

[0120]

[0121]

[0122] Among them, α AB is the conversion coefficient of the line voltage between phase A and phase B in the three-phase line voltage, α BC is the conversion coefficient of the line voltage between phase B and phase C in the three-phase line voltage, α CA is the conversion coefficient of the line voltage between phase C and phase A in the three-phase line voltage, θ is the phase difference between the positive and negative sequence voltages corresponding to the three-phase line voltage, and ε is the negative sequence voltage unbalance corresponding to the three-phase line voltage.

[0123] Table 1. Voltage harmonic parameters measured by different measuring instruments.

[0124]

[0125] As can be seen from Table 1, since the measured value of measuring instrument 3 is a standard value without error, but measuring instrument 3 is installed with a harmonic eliminator, its safety is insufficient, but the measured value is accurate. Measuring instrument 1 is the harmonic data of the three-phase phase voltage value calculated using the method of this application. From the data, it can be seen that the error between the harmonic data of the three-phase phase voltage value calculated using the method of this application and the actual value is very small, while the error between the harmonic data of the three-phase phase voltage value directly measured by measuring instrument 2 and the actual value is very large. Both measuring instrument 1 and measuring instrument 2 are installed with harmonic eliminators to ensure the safety of power grid operation, but the harmonic eliminator makes the error of measuring instrument 2 very large, but the numerical error calculated using the method of this application is particularly small.

[0126] It should be understood that although Figure 1 , 4 The steps in the flowcharts of , 6, and 7 are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1 , 4 At least part of the steps in , 6, and 7 may include multiple steps or multiple stages. These steps or stages do not necessarily have to be executed at the same time, but can be executed at different times. The execution order of these steps or stages does not necessarily have to be sequentially, but can be executed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0127] In one embodiment, Fig. 9As shown, a device for eliminating harmonic voltage measurement errors in a power grid is provided. The power grid includes an electromagnetic voltage transformer, and a harmonic elimination device is arranged between the neutral point of the primary winding of the electromagnetic voltage transformer and the ground. The device includes: a voltage fundamental wave determination module 901, a voltage parameter determination module 902, a conversion coefficient determination module 903, and a voltage harmonic determination module 904, wherein:

[0128] The voltage fundamental wave determination module 901 is used to obtain the fundamental wave positive sequence voltage and fundamental wave negative sequence voltage corresponding to the three-phase line voltage of the power grid.

[0129] The voltage parameter determination module 902 is used to determine the negative sequence voltage imbalance and the positive and negative sequence voltage phase difference of the three-phase line voltage according to the fundamental positive sequence voltage and the fundamental negative sequence voltage.

[0130] The conversion coefficient determination module 903 is used to determine three conversion coefficients corresponding to the three-phase line voltages according to the negative sequence voltage imbalance, the positive and negative sequence voltage phase difference, and a preset negative sequence voltage imbalance threshold.

[0131] The voltage harmonic determination module 904 is used to obtain the harmonic data corresponding to the three-phase line voltages, and determine the harmonic data of the three-phase phase voltages of the power grid according to the harmonic data corresponding to the three-phase line voltages and three conversion coefficients.

[0132] For the specific definition of the power grid harmonic voltage measurement error elimination device, please refer to the definition of the power grid harmonic voltage measurement error elimination method mentioned above, which will not be repeated here. Each module in the above-mentioned power grid harmonic voltage measurement error elimination device can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory in the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules. It should be noted that the division of modules in the embodiment of the present application is schematic, which is only a logical function division, and there may be other division methods in actual implementation.

[0133] In one embodiment, a computer device is provided, wherein the internal structure diagram of the computer device can be as follows: Fig.10 As shown. The computer device includes a processor, a memory and a network interface connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for eliminating power grid harmonic voltage measurement errors is implemented.

[0134] Those skilled in the art will understand that Fig.10 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0135] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0136] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0137] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0138] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0139] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0140] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0141] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for eliminating power grid harmonic voltage measurement errors, It is characterized in that The power grid includes an electromagnetic voltage transformer, a detuning device is provided between a neutral point of a primary winding of the electromagnetic voltage transformer and the ground, and the method includes: Obtaining a fundamental positive-sequence voltage and a fundamental negative-sequence voltage corresponding to a three-phase line voltage of the power grid; Respectively obtaining the amplitude and phase of the fundamental positive-sequence voltage and the fundamental negative-sequence voltage; Determining a negative-sequence voltage imbalance of the three-phase line voltage according to the amplitude of the fundamental positive-sequence voltage and the amplitude of the fundamental negative-sequence voltage; Determining a positive-sequence voltage phase difference between the three-phase line voltage and the negative-sequence voltage phase difference according to the phase of the fundamental positive-sequence voltage and the phase of the fundamental negative-sequence voltage; According to the negative sequence voltage imbalance, the positive and negative sequence voltage phase difference, and a preset negative sequence voltage imbalance threshold, three conversion coefficients corresponding to the three-phase line voltages are determined, including determining the three conversion coefficients corresponding to the three-phase line voltages by the following formula: in, is the conversion coefficient of the line voltage between phase A and phase B in the three-phase line voltage, is the conversion coefficient of the line voltage between phase B and phase C in the three-phase line voltage, is the conversion coefficient of the line voltage between phase C and phase A in the three-phase line voltage, is the positive and negative sequence voltage phase difference corresponding to the three-phase line voltage, is the negative sequence voltage unbalance corresponding to the three-phase line voltage, is the preset negative sequence voltage imbalance threshold; The harmonic data corresponding to the three-phase line voltages are obtained, and the harmonic data of the three-phase phase voltages of the power grid are determined according to the harmonic data corresponding to the three-phase line voltages and the three conversion coefficients.

2. The method according to claim 1, It is characterized in that The obtaining of a fundamental positive-sequence voltage and a fundamental negative-sequence voltage corresponding to the three-phase line voltage of the power grid includes: Acquire the three-phase line voltage of the power grid, and determine the fundamental voltage amplitude and fundamental voltage phase respectively corresponding to the three-phase line voltage according to the three-phase line voltage, wherein the three-phase line voltage includes the line voltage between phase A and phase B, the line voltage between phase B and phase C, and the line voltage between phase C and phase A; The fundamental positive-sequence voltage and the fundamental negative-sequence voltage corresponding to the three-phase line voltage are determined according to the fundamental voltage amplitudes and fundamental voltage phases respectively corresponding to the three-phase line voltages.

3. The method according to claim 2, It is characterized in that The determining of the fundamental positive-sequence voltage and the fundamental negative-sequence voltage corresponding to the three-phase line voltage according to the fundamental voltage amplitudes and fundamental voltage phases respectively corresponding to the three-phase line voltages comprises: Specifically, the fundamental positive-sequence voltage and the fundamental negative-sequence voltage corresponding to the three-phase line voltage are determined by the following formula: in, is the fundamental positive sequence voltage corresponding to the three-phase line voltage, is the fundamental negative sequence voltage corresponding to the three-phase line voltage, is the fundamental voltage amplitude of the line voltage between phase A and phase B in the three-phase line voltage, is the fundamental voltage amplitude of the line voltage between phases B and C in the three-phase line voltage, is the fundamental voltage amplitude of the line voltage between phase C and phase A in the three-phase line voltage, is the fundamental voltage phase of the line voltage between phase A and phase B in the three-phase line voltage, is the fundamental voltage phase of the line voltage between phases B and C in the three-phase line voltage, It is the fundamental voltage phase of the line voltage between phase C and phase A in the three-phase line voltage.

4. The method according to claim 1, It is characterized in that Determining the negative-sequence voltage imbalance of the three-phase line voltage according to the amplitude of the fundamental positive-sequence voltage and the amplitude of the fundamental negative-sequence voltage includes: The negative sequence voltage unbalance of the three-phase line voltage is determined by the following formula: in, is the negative sequence voltage unbalance corresponding to the three-phase line voltage, is the amplitude of the fundamental negative sequence voltage corresponding to the three-phase line voltage, It is the amplitude of the fundamental positive sequence voltage corresponding to the three-phase line voltage.

5. The method according to claim 1, It is characterized in that The harmonic data of the three-phase voltage includes the total harmonic distortion rate of the three-phase voltage and the content rate of each harmonic of the three-phase voltage, the harmonic data of the three-phase line voltage includes the total harmonic distortion rate of the three-phase line voltage and the content rate of each harmonic of the three-phase line voltage, and the obtaining of the harmonic data corresponding to the three-phase line voltages, and determining the harmonic data of the three-phase voltage of the power grid according to the harmonic data corresponding to the three-phase line voltages and the three conversion coefficients, includes: Determine the total harmonic distortion rate of the phase voltage of phase A among the three-phase phase voltages of the power grid according to the total harmonic distortion rate and the conversion coefficient of the line voltage between phase A and phase B of the power grid; Determine the total harmonic distortion rate of the phase B voltage among the three-phase phase voltages of the power grid according to the total harmonic distortion rate and the conversion coefficient of the line voltage between the phase B and the phase C of the power grid; Determine the total harmonic distortion rate of the phase voltage of phase C among the three-phase phase voltages of the power grid according to the total harmonic distortion rate and the conversion coefficient of the line voltage between phase C and phase A of the power grid; Determine the harmonic content of the phase voltage of phase A in the three-phase voltage of the power grid according to the harmonic content and conversion coefficient of the line voltage between phase A and phase B of the power grid; Determine the harmonic content of the phase B voltage in the three-phase voltage of the power grid according to the harmonic content and conversion coefficient of the line voltage between the phase B and the phase C of the power grid; The harmonic content rates of the phase voltage of phase C among the three-phase voltages of the power grid are determined according to the harmonic content rates and conversion coefficients of the line voltages between phase C and phase A of the power grid.

6. The method according to claim 1, It is characterized in that After obtaining the three-phase line voltage of the power grid, the method further includes: The acquired three-phase line voltages are synthesized to obtain a complete three-phase line voltage of the power grid; The phase sequence of the three-phase line voltage is adjusted so that the phase sequence of the three-phase line voltage is a positive sequence.

7. A device for eliminating harmonic voltage measurement errors in power grid, It is characterized in that The power grid includes an electromagnetic voltage transformer, a detuning device is provided between the neutral point of the primary winding of the electromagnetic voltage transformer and the ground, and the device includes: A voltage fundamental wave determination module, used for obtaining a fundamental wave positive-sequence voltage and a fundamental wave negative-sequence voltage corresponding to the three-phase line voltage of the power grid; A voltage parameter determination module, used to respectively obtain the amplitude and phase of the fundamental positive sequence voltage and the fundamental negative sequence voltage; determine the negative sequence voltage imbalance of the three-phase line voltage according to the amplitude of the fundamental positive sequence voltage and the amplitude of the fundamental negative sequence voltage; determine the positive and negative sequence voltage phase difference of the three-phase line voltage according to the phase of the fundamental positive sequence voltage and the phase of the fundamental negative sequence voltage; A conversion coefficient determination module is used to determine three conversion coefficients corresponding to the three-phase line voltages according to the negative sequence voltage imbalance, the positive and negative sequence voltage phase difference, and a preset negative sequence voltage imbalance threshold, including determining the three conversion coefficients corresponding to the three-phase line voltages according to the following formula: in, is the conversion coefficient of the line voltage between phase A and phase B in the three-phase line voltage, is the conversion coefficient of the line voltage between phase B and phase C in the three-phase line voltage, is the conversion coefficient of the line voltage between phase C and phase A in the three-phase line voltage, is the positive and negative sequence voltage phase difference corresponding to the three-phase line voltage, is the negative sequence voltage unbalance corresponding to the three-phase line voltage, is the preset negative sequence voltage imbalance threshold; The voltage harmonic determination module is used to obtain the harmonic data corresponding to the three-phase line voltages respectively, and determine the harmonic data of the three-phase phase voltages of the power grid according to the harmonic data corresponding to the three-phase line voltages respectively and the three conversion coefficients.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program. It is characterized in that When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, It is characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product comprising a computer program, It is characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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