High-precision measurement method and device for initial phase angle based on automatic correction of double-point angle difference

Abstract

A high-precision measurement method for the initial phase angle based on automatic correction of the two-point angle difference and a measurement device thereof relate to the technical field of electrical signal measurement for relay protection devices. In order to address the defects of existing electrical signal angle calibration devices, such as being limited by sampling frequency, having large error in difference estimation, and being unable to perform dynamic compensation, an electrical signal mutation is used to measure the initial phase angle and cycle data; the angle difference between the second point and the first point is calculated based on the cycle data; the reference angle is calculated based on the number of sampling points, and the compensation reference is calculated; a compensation coefficient model is used to obtain an angle dynamic compensation coefficient, and the initial phase angle is dynamically compensated based on the angle difference; the real-time phase angle difference is calibrated, and the initial phase angle is calibrated based on the real-time phase angle difference. The present invention is mainly used to compensate for the mutation of electrical signals.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical signal measurement of relay protection devices, and in particular to a high-precision initial phase angle measurement method based on automatic correction of double-point angle difference and a measuring device thereof. Background Art

[0002] When calculating the initial angle for the voltage and current input to the relay protection device, a Fourier filter algorithm is typically used to obtain the voltage and current vectors, and thus the angle. However, this approach often results in significant errors and is limited by the number of sampling points. For example, with 32 sampling points, the angle between the current and next sampling points is 360 / 32 = 11.25 degrees. In this case, the error between the calculated initial phase angle and the actual amount added reaches 11.25 degrees. Increasing the number of sampling points can only slightly improve this error. Furthermore, this is only a theoretical error and does not take into account the accuracy of the initial point capture. If there are fluctuations during the initial phase, the angle calculation will also result in certain errors. These errors are objective and unavoidable.

[0003] In existing technologies, angle calibration is typically achieved through hardware synchronization or software interpolation. However, due to sampling frequency limitations, angle errors are still difficult to avoid. Currently, there are angle compensation methods based on linear interpolation, which estimate the true angle by linearly interpolating between adjacent sampling points. However, this method does not account for the nonlinear characteristics of angle variation, and the compensation amount is fixed, making dynamic compensation impossible, resulting in large errors.

[0004] Therefore, there is a need for a high-precision measurement method and a measuring device for the initial phase angle based on automatic correction of the double-point angle difference, which can dynamically compensate for the sampling angle with high precision, have small error, high precision, and dynamically compensate for the phase angle difference. Summary of the Invention

[0005] The present invention aims to solve the defects of existing electrical signal angle calibration devices, such as being limited by sampling frequency, having large difference estimation errors, and being unable to perform dynamic compensation. It provides a high-precision measurement method and a measurement device for the initial phase angle based on automatic correction of the double-point angle difference, which can dynamically compensate for the sampling angle with high precision, have small errors, high precision, and can dynamically compensate for the phase angle difference.

[0006] The high-precision measurement method of the initial phase angle based on automatic correction of the double-point angle difference of the present invention comprises the following steps:

[0007] S1. Use the electrical signal mutation amount to measure the initial phase angle and frequency data;

[0008] S2. Calculate the angle difference between the second point and the first point based on the frequency data;

[0009] S3. Calculate the reference angle and compensation reference amount based on the number of sampling points ;

[0010] S4. Preset a dynamic compensation coefficient and dynamically compensate the initial phase angle according to the angle difference ΔA;

[0011] S5. Calibrate the real-time phase angle difference, and calibrate the initial phase angle according to the real-time phase angle difference.

[0012] Furthermore, the triggering condition for measuring the initial phase angle is: when the relay protection device detects a sudden change in voltage or current, the initial phase angle measurement function is automatically started.

[0013] Furthermore, the angle difference calculation process is as follows: the first point is the first point where the mutation is initiated, and the angle A1 of the first point is calculated based on the Fourier algorithm using one cycle of data starting from the first point; the angle A2 of the second point is calculated using one cycle of data starting from the second point, and then the difference ∆A=A2-A1 is calculated.

[0014] Furthermore, the dynamically compensating the initial phase angle according to the angle difference ΔA includes:

[0015] When the angle difference ∆A is between 10.0 and 11.5 degrees, the initial phase angle A=A1-1.2* ;

[0016] When the angle difference ∆A is between 11.6 and 12.0 degrees, the initial phase angle A = A1-1.0* ;

[0017] When the angle difference ∆A is between 12.0 and 12.4 degrees, the initial phase angle A = A1-0.8* ;

[0018] When the angle difference ∆A is between 12.5 and 13.5 degrees, the initial phase angle A=A1-0.1* ;

[0019] When the angle difference ∆A is between 13.6 and 14.5 degrees, the initial phase angle A=A1;

[0020] When the angle difference ∆A is between 14.5 and 15.9 degrees, the initial phase angle A=A1+0.5*(∆A / A0)* ;

[0021] When the angle difference ∆A is 16.0 degrees or above, the initial phase angle A=A1+0.8*(∆A / A0)* ;

[0022] Among them, A0 is the reference angle.

[0023] Furthermore: the steps for calculating the real-time phase angle difference are:

[0024] Calculate the real-time phase angle of the current three-phase electricity;

[0025] Calculate the real-time phase angle difference and the initial phase angle difference of phases AB, BC, and CA, and then continue to calculate the difference between the real-time phase angle difference and the initial phase angle difference of phases AB, BC, and CA to find the minimum difference between the two phases.

[0026] Calculate the difference between the real-time phase angle difference and the initial phase angle difference, and find the two phases with the smallest difference.

[0027] Furthermore, the calibrating the initial phase angle specifically includes:

[0028] Calculate the real-time phase angle difference, calculate the difference between the real-time phase angle difference and the initial phase angle difference, and find the two phases with the smallest difference; use the two phases with the smallest difference as the reference phase, and correct the initial phase angle of the third phase according to the real-time phase angle difference.

[0029] The measuring device for realizing the high-precision measurement method of the initial phase angle based on automatic correction of the double-point angle difference described in the present invention comprises a signal acquisition device, a dynamic compensation module and a difference correction module;

[0030] The signal acquisition device is used to collect the mutation amount and frequency data of the electrical signal;

[0031] The dynamic compensation module is used to dynamically compensate for the angle difference of the electrical signal;

[0032] The difference correction module is used to correct the initial phase angle.

[0033] The beneficial effects of the present invention are:

[0034] The present invention provides a calibration method based on dual-point angle band compensation. This method can significantly reduce the angle error caused by the limitation of the number of sampling points. Taking 32-point sampling as an example, the error is less than 2 degrees in most cases, and the maximum error is about 5 degrees. Based on the dual-point angle difference, the present invention introduces a real-time phase angle difference high-precision calibration mechanism to further calibrate the initial phase angle; a high-precision compensation coefficient model for sampling the initial phase angle dynamically compensates the initial sampling angle, and improves the calculation accuracy of the initial phase angle of the device. This makes it possible to obtain relatively accurate initial current and voltage addition angles without changing the sampling rate, saving costs and meeting on-site needs.

[0035] The present invention introduces a real-time high-precision phase angle difference calibration mechanism. According to the three-phase phase angle difference calculated at the current moment, it compares the initial phase angle difference of the three phases, takes the two phases with the smallest difference as the reference phase, and corrects the initial phase angle calculation value of the other phase, further improving the accuracy and reducing the situation where the error of a certain phase is too large. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The figure is a flow chart of a high-precision measurement method of an initial phase angle based on automatic correction of a two-point angle difference. DETAILED DESCRIPTION

[0037] The following are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the scope of protection of the present invention. The embodiments described below are only used to explain the present invention and cannot be interpreted as limiting the present invention. The scope of protection of the present invention should be based on the scope of protection of the claims. The embodiments of the present invention are described in detail below. In order to facilitate the description of the present invention and simplify the description, the technical terms used in the description of the present invention should be interpreted broadly, including but not limited to conventional replacement schemes not mentioned in this application, and also including direct implementation and indirect implementation.

[0038] Example 1

[0039] Combine Figure 1 This embodiment describes a high-precision measurement method for an initial phase angle based on automatic correction of a two-point angle difference, including the following steps:

[0040] S1. Use the electrical signal mutation amount to measure the initial phase angle and frequency data;

[0041] Measure the initial phase angle;

[0042] The initial phase angle measurement method is started by using a sudden change. When voltage and current are applied to the device, the initial phase angle measurement function is started.

[0043] Trigger condition: When the relay protection device detects a sudden change in voltage or current, the initial phase angle measurement function automatically starts.

[0044] Data recording: Starting from the first point where the sudden change occurs, record the data for one cycle (complete cycle) plus one sampling point. For example, for a 32-point sampling system, record 33 sampling points.

[0045] S2. Calculate the angle difference ΔA between the second point and the first point based on the frequency data;

[0046] Data preparation and preliminary calculations;

[0047] After data preparation is complete, use the data from the first point to calculate the angle A1 of the first point based on the Fourier algorithm. Use the data from the second point to calculate the angle A2 of the second point. Then calculate the difference ∆A = A2 - A1.

[0048] After startup, record and sample one cycle + one point of data starting from the first mutation starting point;

[0049] Fourier algorithm calculates angle:

[0050] Calculate the initial phase angle A1 using one cycle of data (32 points) starting from the first sampling point.

[0051] Calculate the initial phase angle A2 using one cycle of data starting from the second sampling point.

[0052] Calculate the angle difference: ΔA=A2−A1.

[0053] S3. Calculate the reference angle and compensation reference amount based on the number of sampling points ;

[0054] Calculation of reference angle and compensation reference amount;

[0055] Calculate the reference angle A0 based on the number of sampling points; taking 32 points as an example, based on the number of sampling points 32, calculate the reference angle A0=360 / 32=11.25°, and the compensation reference amount Acomp=11.25 / 2≈5.6°. According to the Fourier series algorithm, the 32-point sampling data can be decomposed into the real part , imaginary part , in one coordinate axis, the actual phase of this frequency analog quantity can be obtained by using the inverse trigonometric function algorithm from the real and imaginary parts. The formula after the real and imaginary parts of the Fourier algorithm are simplified is:

[0056] ;

[0057] ;

[0058] Where N is the number of sampling points in a cycle, and n is a multiple of the fundamental frequency (n=1, 2, 3, etc.). For a 32-point full-cycle Fourier fundamental algorithm, N=32 and n=1. k refers to the current point, from 0 to N-1, for a total of N points. is the sampling value of the kth point.

[0059] S4. Preset a dynamic compensation coefficient and dynamically compensate the initial phase angle according to the angle difference ΔA;

[0060] According to experimental tests, the angle dynamic compensation coefficient is summarized. A lot of raw data is obtained through a large number of experiments, including the angle difference data between the second point and the first point, and the angle difference data between the added analog quantity and the initial phase angle calculation value. By drawing data points on the table axis and performing segmented fitting according to the degree of discreteness, the approximate compensation model and approximate compensation coefficient are obtained.

[0061] Dynamic compensation is performed based on the angle difference ΔA. The dynamic compensation satisfies the following relationship:

[0062] The angle difference ∆A is between 10.0 and 11.5 degrees, and the initial phase angle A = A1 - 1.2 * Acomp;

[0063] The angle difference ∆A is between 11.6 and 12.0 degrees, and the initial phase angle A = A1 - 1.0 * Acomp;

[0064] The angle difference ∆A is between 12.0 and 12.4 degrees, and the initial phase angle A = A1 - 0.8 * Acomp;

[0065] The angle difference ∆A is between 12.5 and 13.5 degrees, and the initial phase angle A = A1 - 0.1 * Acomp;

[0066] The angle difference ∆A is between 13.6 and 14.5 degrees, and the initial phase angle A=A1;

[0067] The angle difference ∆A is between 14.5 and 15.9 degrees, and the initial phase angle A=A1+0.5*(∆A / A0)*Acomp;

[0068] When the angle difference ∆A is 16.0 degrees or greater, the initial phase angle A=A1+0.8*(∆A / A0)*Acomp.

[0069] S5. Calibrate the real-time phase angle difference, and calibrate the initial phase angle according to the real-time phase angle difference.

[0070] Calculate the real-time phase angle difference:

[0071] First, calculate the real-time phase angle of the current three-phase electricity (phases A, B, and C); this phase angle is calculated in real time based on the current sampling value, and there is almost no phase angle error.

[0072] Then calculate the real-time phase angle difference and the initial phase angle difference of the AB phase, BC phase, and CA phase, and continue to calculate the difference between the real-time phase angle difference and the initial phase angle difference of the AB phase, BC phase, and CA phase to find the difference between the minimum two phases.

[0073] Finally, calculate the difference between the real-time phase angle difference and the initial phase angle difference, and find the two phases with the smallest difference;

[0074] Calculate the initial phase angle of the first two points, and according to the size of the double-point angle difference, substitute it into the high-precision compensation model to dynamically compensate the initial phase angle calculation angle, and significantly correct the initial phase angle measurement error.

[0075] Compared with single-point calculation of the initial phase angle, the calculation accuracy is greatly improved; compared with double-point calculation of linear compensation, the accuracy can also be further improved.

[0076] Calibrate the initial phase angle:

[0077] The two phases with the smallest difference are used as the reference phases (such as phases A and B). The initial phase angle of the third phase (such as phase C) is corrected based on the real-time phase angle difference. For example, if the difference between phases A and B is the smallest, the initial phase angle of phase C is adjusted based on the initial phase angle of phase A or phase B.

[0078] This embodiment uses the difference between the minimum real-time phase angle difference between the two phases and the initial phase angle difference as a reference. Based on the initial phase angle of the reference phase, the initial phase angle of the other phase is calculated based on the real-time phase angle difference. For example, if the difference between phases A and B is the smallest, the initial phase angle of phase A or B is used as the reference phase, and phase C is corrected based on the real-time phase angle difference. This method can correct initial phase angles with large errors, resulting in more accurate initial phase angle measurements.

[0079] Universal expansion: This initial phase angle measurement calculation method is also applicable to systems with different numbers of sampling points, such as 40 points and 96 points. The higher the sampling rate, the better the actual effect and the higher the initial phase angle measurement accuracy.

[0080] Verification and output: Verify the accuracy of the compensation model through experimental testing to ensure that the error is within an acceptable range (for example, the error is less than 2 degrees when sampling 32 points, and the maximum does not exceed 5.6 degrees), and output the final high-precision initial phase angle measurement value.

Claims

1. A high-precision measurement method for initial phase angle based on automatic correction of double-point angle difference, characterized in that: The steps include: S1. Use the electrical signal mutation amount to measure the initial phase angle and frequency data; S2. Calculate the angle difference ΔA between the second point and the first point based on the cycle data. The angle difference calculation process is as follows: the first point is the first point where the sudden change is initiated, and the angle A1 of the first point is calculated based on the Fourier algorithm using the cycle data starting from the first point. The angle A2 of the second point is calculated using the cycle data starting from the second point, and then the difference ΔA is calculated as A2-A1. S3. Calculate the reference angle and compensation reference amount based on the number of sampling points ; S4. Preset a dynamic compensation coefficient and dynamically compensate the initial phase angle according to the angle difference ΔA; S5, calibrating the real-time phase angle difference, and calibrating the initial phase angle according to the real-time phase angle difference; The calibration of the initial phase angle specifically includes: Calculating a real-time phase angle difference, calculating the difference between the real-time phase angle difference and the initial phase angle difference, and finding the two phases with the smallest difference; The two phases with the smallest difference are used as reference phases, and the initial phase angle of the third phase is corrected according to the real-time phase angle difference.

2. The high-precision measurement method for initial phase angle based on automatic correction of double-point angle difference according to claim 1 is characterized in that: The triggering condition for measuring the initial phase angle is: when the relay protection device detects a sudden change in voltage or current, the initial phase angle measurement function is automatically started.

3. The high-precision measurement method for initial phase angle based on automatic correction of double-point angle difference according to claim 1, characterized in that: The dynamic compensation of the initial phase angle according to the angle difference ΔA comprises: When the angle difference ΔA is between 10.0 and 11.5 degrees, the initial phase angle A=A1-1.2* ; When the angle difference ΔA is between 11.6 and 12.0 degrees, the initial phase angle A=A1-1.0* ; When the angle difference ΔA is between 12.0 and 12.4 degrees, the initial phase angle A=A1-0.8* ; When the angle difference ΔA is between 12.5 and 13.5 degrees, the initial phase angle A=A1-0.1* ; When the angle difference ΔA is between 13.6 and 14.5 degrees, the initial phase angle A=A1; When the angle difference ΔA is between 14.5 and 15.9 degrees, the initial phase angle A=A1+0.5*(∆A / A0)* ; When the angle difference ΔA is 16.0 degrees or above, the initial phase angle A=A1+0.8*(∆A / A0)* ; Among them, A0 is the reference angle.

4. The high-precision measurement method for initial phase angle based on automatic correction of double-point angle difference according to claim 1, characterized in that: The calculation steps of the real-time phase angle difference are: Calculate the real-time phase angle of the current three-phase electricity; Calculate the real-time phase angle difference and the initial phase angle difference of phases AB, BC, and CA, and then continue to calculate the difference between the real-time phase angle difference and the initial phase angle difference of phases AB, BC, and CA to find the minimum difference between the two phases. Calculate the difference between the real-time phase angle difference and the initial phase angle difference, and find the two phases with the smallest difference.

5. A measuring device for implementing the high-precision measurement method of the initial phase angle based on automatic correction of the double-point angle difference according to any one of claims 1 to 4, characterized in that: It includes a signal acquisition device, a dynamic compensation module and a difference correction module; The signal acquisition device is used to collect the mutation amount and frequency data of the electrical signal; The dynamic compensation module is used to dynamically compensate for the angle difference of the electrical signal; The difference correction module is used to correct the initial phase angle.

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