Voltage amplitude and phase detection method and device suitable for voltage sag detection

Abstract

The invention relates to the technical field of voltage fault detection, and particularly provides a voltage amplitude and phase detection method and device suitable for voltage sag detection, and the method comprises the steps: carrying out the primary filtering of a voltage sampling value of a to-be-detected sampling period based on the voltage sampling values of two sampling periods before the to-be-detected sampling period, obtaining a primary filtering value of the to-be-measured sampling period; performing secondary filtering on the primary filtering value of the to-be-measured sampling period by adopting a second-order low-pass filter to obtain a secondary filtering value of the to-be-measured sampling period; performing weighted average on the primary filtering value and the secondary filtering value of the to-be-measured sampling period to obtain a weighted average value of the to-be-measured sampling period; and determining a voltage amplitude and a phase angle of the to-be-measured sampling period based on the weighted average of the to-be-measured sampling period. According to the technical scheme, the amplitude and phase of the single-phase voltage can be determined based on the continuous power grid voltage sampling values, and the method is suitable for amplitude and phase detection of asymmetric drop of the three-phase voltage of the power grid voltage and has rapidity and reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of voltage fault detection, and in particular to a voltage amplitude and phase detection method and device suitable for voltage sag detection. Background Art

[0002] Voltage sag is usually caused by faults in the power grid or substation facilities or a significant change in load. It is a short-term disturbance phenomenon in which the root mean square value of the power grid voltage suddenly drops to 90% to 10% of the rated voltage and returns to normal after 0.01s to 1min. Since complex loads such as power system faults caused by severe weather such as lightning strikes, short circuit faults, large motor starting and capacitor switching are inevitable in the power transmission and distribution system, voltage sag faults occur frequently.

[0003] In order to solve the voltage sag problem, dynamic voltage restorers and uninterruptible power supplies are usually used. The performance of these control devices depends on the detection speed and accuracy of grid voltage sag. As an important part of its control strategy, it is particularly important to improve the speed and accuracy of voltage amplitude and phase detection suitable for voltage sag detection.

[0004] Existing three-phase asymmetric voltage detection mostly uses the dq transformation method, which requires the voltage frequency to be known for Park transformation. At the same time, except for the αβ-dq transformation method based on derivative construction (this method is easy to amplify system noise), it is necessary to construct one or two phases of voltage through delay, and perform coordinate transformation on this basis to calculate the voltage amplitude and phase, which restricts the detection speed to a certain extent. Summary of the invention

[0005] In order to overcome the above-mentioned defects, the present invention proposes a voltage amplitude and phase detection method and device suitable for voltage sag detection.

[0006] In a first aspect, a voltage amplitude and phase detection method applicable to voltage sag detection is provided, and the voltage amplitude and phase detection method applicable to voltage sag detection includes:

[0007] Based on the voltage sampling values ​​of the two sampling periods before the sampling period to be measured, the voltage sampling value of the sampling period to be measured is filtered once to obtain a primary filtering value of the sampling period to be measured;

[0008] Using a second-order low-pass filter to perform secondary filtering on the primary filtering value of the sampling period to be measured, to obtain the secondary filtering value of the sampling period to be measured;

[0009] Performing weighted averaging on the primary filtering value and the secondary filtering value of the sampling period to be measured to obtain a weighted average value of the sampling period to be measured;

[0010] The voltage amplitude and phase angle of the sampling period to be measured are determined based on the weighted average value of the sampling period to be measured.

[0011] Preferably, the primary filtering value of the sampling period to be measured is as follows:

[0012]

[0013] In the above formula, is the primary filtering value of the kth sampling period, the kth sampling period is the sampling period to be measured, are the squares of the voltage sampling values ​​of the kth, k-1th, and k-2th sampling periods, respectively, T s is the number of sampling periods, w 0 is the nominal angular frequency of the power grid.

[0014] Furthermore, the secondary filtering value of the sampling period to be measured is as follows:

[0015]

[0016] In the above formula, are the secondary filtering values ​​of the kth, k-1th, and k-2th sampling periods, ξ is the damping coefficient, and w c is the cut-off frequency, They are the primary filtering values ​​of the k-1th and k-2th sampling periods respectively.

[0017] Furthermore, the weighted average value of the sampling period to be measured is as follows:

[0018]

[0019] In the above formula, F(k) is the weighted average value of the kth sampling period, and W(k) is the weight coefficient of the kth sampling period.

[0020] Furthermore, the weight coefficient of the kth sampling period is as follows:

[0021]

[0022] In the above formula, e is a natural constant, β is a preset adjustable parameter, and k d It is the sampling period when the voltage drops.

[0023] Furthermore, the updating process of the sampling period when the voltage drops includes:

[0024] Determine the voltage drop flag of the kth sampling period based on the primary filtering value of the kth sampling period;

[0025] When the voltage drop flag bit of the kth sampling cycle is 1, update k d =k.

[0026] Furthermore, the voltage drop flag of the kth sampling period is as follows:

[0027]

[0028] In the above formula, flag k is the voltage drop flag of the kth sampling period, and α is the voltage drop detection threshold.

[0029] Preferably, the voltage amplitude and phase angle of the sampling period to be measured are as follows:

[0030]

[0031] φ(k)=asin(U(k) / A(k))

[0032] In the above formula, A(k) is the voltage amplitude of the kth sampling period, the kth sampling period is the sampling period to be measured, F(k) is the weighted average value of the kth sampling period, φ(k) is the voltage phase angle of the kth sampling period, and U(k) is the voltage sampling value of the kth sampling period.

[0033] In a second aspect, a voltage amplitude and phase detection device suitable for voltage sag detection is provided, and the voltage amplitude and phase detection device suitable for voltage sag detection comprises:

[0034] A first filtering module, configured to perform a primary filtering on the voltage sampling value of the sampling period to be measured based on the voltage sampling values ​​of the two sampling periods before the sampling period to be measured, so as to obtain a primary filtering value of the sampling period to be measured;

[0035] A second filtering module is used to perform secondary filtering on the primary filtering value of the sampling period to be measured by using a second-order low-pass filter to obtain a secondary filtering value of the sampling period to be measured;

[0036] A third filtering module, used for performing weighted averaging on the primary filtering value and the secondary filtering value of the sampling period to be measured to obtain a weighted average value of the sampling period to be measured;

[0037] A determination module is used to determine the voltage amplitude and phase angle of the sampling period to be measured based on the weighted average value of the sampling period to be measured.

[0038] Preferably, the primary filtering value of the sampling period to be measured is as follows:

[0039]

[0040] In the above formula, is the primary filtering value of the kth sampling period, the kth sampling period is the sampling period to be measured, are the squares of the voltage sampling values ​​of the kth, k-1th, and k-2th sampling periods, respectively, T s is the number of sampling periods, w 0 is the nominal angular frequency of the power grid.

[0041] Furthermore, the secondary filtering value of the sampling period to be measured is as follows:

[0042]

[0043] In the above formula, are the secondary filtering values ​​of the kth, k-1th, and k-2th sampling periods, respectively, (is the damping coefficient, w c is the cut-off frequency, They are the primary filtering values ​​of the k-1th and k-2th sampling periods respectively.

[0044] Furthermore, the weighted average value of the sampling period to be measured is as follows:

[0045]

[0046] In the above formula, V(k) is the weighted average value of the kth sampling period, and W(k) is the weight coefficient of the kth sampling period.

[0047] Furthermore, the weight coefficient of the kth sampling period is as follows:

[0048]

[0049] In the above formula, e is a natural constant, β is a preset adjustable parameter, and k d It is the sampling period when the voltage drops.

[0050] Furthermore, the updating process of the sampling period when the voltage drops includes:

[0051] Determine the voltage drop flag of the kth sampling period based on the primary filtering value of the kth sampling period;

[0052] When the voltage drop flag bit of the kth sampling cycle is 1, update k d =k.

[0053] Furthermore, the voltage drop flag of the kth sampling period is as follows:

[0054]

[0055] In the above formula, flag k is the voltage drop flag of the kth sampling period, and α is the voltage drop detection threshold.

[0056] Preferably, the voltage amplitude and phase angle of the sampling period to be measured are as follows:

[0057]

[0058] φ(k)=asin(U(k) / A(k))

[0059] In the above formula, A(k) is the voltage amplitude of the kth sampling period, the kth sampling period is the sampling period to be measured, F(k) is the weighted average value of the kth sampling period, φ(k) is the voltage phase angle of the kth sampling period, and U(k) is the voltage sampling value of the kth sampling period.

[0060] In a third aspect, a computer device is provided, comprising: one or more processors;

[0061] The processor is configured to execute one or more programs;

[0062] When the one or more programs are executed by the one or more processors, the voltage amplitude and phase detection method suitable for voltage sag detection is implemented.

[0063] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed, the voltage amplitude and phase detection method suitable for voltage sag detection is implemented.

[0064] The above one or more technical solutions of the present invention have at least one or more of the following beneficial effects:

[0065] The present invention provides a voltage amplitude and phase detection method and device suitable for voltage sag detection, including: filtering the voltage sampling value of the sampling period to be measured based on the voltage sampling values ​​of the two sampling periods before the sampling period to be measured, and obtaining the primary filtering value of the sampling period to be measured; using a second-order low-pass filter to perform secondary filtering on the primary filtering value of the sampling period to be measured, and obtaining the secondary filtering value of the sampling period to be measured; weighted averaging the primary filtering value and the secondary filtering value of the sampling period to be measured, and obtaining the weighted average value of the sampling period to be measured; determining the voltage amplitude and phase angle of the sampling period to be measured based on the weighted average value of the sampling period to be measured. The technical solution provided by the present invention can determine the amplitude and phase of the single-phase voltage based on continuous grid voltage sampling values, and is suitable for the amplitude and phase detection of asymmetric drops of three-phase voltage of the grid voltage, and has both rapidity and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 It is a schematic flow chart of main steps of a voltage amplitude and phase detection method applicable to voltage sag detection according to an embodiment of the present invention;

[0067] Figure 2 is a single-phase grid voltage variation curve to be detected in an embodiment of the present invention;

[0068] Figure 3 is an amplitude detection curve of an embodiment of the present invention;

[0069] Figure 4 is a phase angle detection curve of an embodiment of the present invention;

[0070] Figure 5 is a voltage drop moment detection curve of an embodiment of the present invention. DETAILED DESCRIPTION

[0071] The specific implementation modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0072] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0073] As disclosed in the background technology, voltage sag is usually caused by failure of the power grid or substation facilities or a significant change in load. It is a short-term disturbance phenomenon in which the root mean square value of the power grid voltage suddenly drops to 90% to 10% of the rated voltage, lasts for 0.01s to 1min, and then returns to normal. Due to the inevitable existence of complex loads such as power system failures caused by severe weather such as lightning strikes, short circuit failures, large motor starting and capacitor switching in the power transmission and distribution system, voltage sag failures occur frequently.

[0074] In order to solve the voltage sag problem, dynamic voltage restorers and uninterruptible power supplies are usually used. The performance of these control devices depends on the detection speed and accuracy of grid voltage sag. As an important part of its control strategy, it is particularly important to improve the speed and accuracy of voltage amplitude and phase detection suitable for voltage sag detection.

[0075] Existing three-phase asymmetric voltage detection mostly uses the dq transformation method, which requires the voltage frequency to be known for Park transformation. At the same time, except for the αβ-dq transformation method based on derivative construction (this method is easy to amplify system noise), it is necessary to construct one or two phases of voltage through delay, and perform coordinate transformation on this basis to calculate the voltage amplitude and phase, which restricts the detection speed to a certain extent.

[0076] In order to improve the above problems, the present invention provides a voltage amplitude and phase detection method and device suitable for voltage sag detection, including: filtering the voltage sampling value of the sampling period to be measured based on the voltage sampling values ​​of the two sampling periods before the sampling period to be measured, and obtaining the primary filtering value of the sampling period to be measured; using a second-order low-pass filter to perform secondary filtering on the primary filtering value of the sampling period to be measured, and obtaining the secondary filtering value of the sampling period to be measured; weighted averaging the primary filtering value and the secondary filtering value of the sampling period to be measured, and obtaining the weighted average value of the sampling period to be measured; determining the voltage amplitude and phase angle of the sampling period to be measured based on the weighted average value of the sampling period to be measured. The technical solution provided by the present invention can determine the amplitude and phase of the single-phase voltage based on continuous grid voltage sampling values, and is suitable for the amplitude and phase detection of asymmetric drops in the three-phase voltage of the grid voltage, and has both rapidity and reliability.

[0077] The above scheme is described in detail below.

[0078] Example 1

[0079] See attached Figure 1 , Figure 1 FIG. 1 is a schematic flow chart of the main steps of a voltage amplitude and phase detection method applicable to voltage sag detection according to an embodiment of the present invention. Figure 1 As shown, the voltage amplitude and phase detection method suitable for voltage sag detection in the embodiment of the present invention mainly includes the following steps:

[0080] Step S101: filtering the voltage sampling value of the sampling period to be measured based on the voltage sampling values ​​of the two sampling periods before the sampling period to be measured, to obtain a primary filtering value of the sampling period to be measured;

[0081] Step S102: using a second-order low-pass filter to perform secondary filtering on the primary filtering value of the sampling period to be measured, to obtain the secondary filtering value of the sampling period to be measured;

[0082] Step S103: performing weighted averaging on the primary filtering value and the secondary filtering value of the sampling period to be measured to obtain a weighted average value of the sampling period to be measured;

[0083] Step S104: determining the voltage amplitude and phase angle of the sampling period to be measured based on the weighted average value of the sampling period to be measured.

[0084] In this embodiment, the primary filtering value of the sampling period to be measured is as follows:

[0085]

[0086] In the above formula, is the primary filtering value of the kth sampling period, the kth sampling period is the sampling period to be measured, are the squares of the voltage sampling values ​​of the kth, k-1th, and k-2th sampling periods, respectively, T s is the number of sampling periods, w 0 is the nominal angular frequency of the power grid, w 0 =100π.

[0087] In one embodiment, the secondary filtering value of the sampling period to be measured is as follows:

[0088]

[0089] In the above formula, are the secondary filtering values ​​of the kth, k-1th, and k-2th sampling periods, ξ is the damping coefficient, and w c is the cut-off frequency, They are the primary filtering values ​​of the k-1th and k-2th sampling periods respectively.

[0090] In one embodiment, the weighted average value of the sampling period to be measured is as follows:

[0091]

[0092] In the above formula, F(k) is the weighted average value of the kth sampling period, and W(k) is the weight coefficient of the kth sampling period.

[0093] In one embodiment, the weight coefficient of the kth sampling period is as follows:

[0094]

[0095] In the above formula, e is a natural constant, β is a preset adjustable parameter, and k d It is the sampling period when the voltage drops.

[0096] In one embodiment, the present invention can effectively determine the time when a voltage drop occurs, and the updating process of the sampling period when the voltage drops occurs includes:

[0097] Determine the voltage drop flag of the kth sampling period based on the primary filtering value of the kth sampling period;

[0098] When the voltage drop flag bit of the kth sampling cycle is 1, update k d =k.

[0099] In one embodiment, the voltage drop flag of the kth sampling period is as follows:

[0100]

[0101] In the above formula, flag kis the voltage drop flag of the kth sampling period, and α is the voltage drop detection threshold.

[0102] In this embodiment, the voltage amplitude and phase angle of the sampling period to be measured are as follows:

[0103]

[0104] φ(k)=asin(U(k) / A(k))

[0105] In the above formula, A(k) is the voltage amplitude of the kth sampling period, the kth sampling period is the sampling period to be measured, F(k) is the weighted average value of the kth sampling period, φ(k) is the voltage phase angle of the kth sampling period, and U(k) is the voltage sampling value of the kth sampling period.

[0106] In a specific implementation manner, the variation curve of the single-phase grid voltage U to be detected is as follows: Figure 2 As shown, at the initial moment, the angular frequency w = 100πrad / s, the amplitude A = 311V, and the initial phase At 0.1s, the angular frequency w jumps 5%, the amplitude A drops 50%, and the phase angle The jump is 30°. The amplitude detection curve is as follows Figure 3 As shown, A f is the true amplitude, A is the amplitude detection value. By observing the curve, we can see that after the voltage amplitude to be detected jumps, the amplitude detection value can converge to the true amplitude quickly. Figure 4 As shown, where φ f is the true phase angle, φ is the phase angle detection value. By observing the curve, we can see that when the voltage phase angle to be detected jumps, the phase angle detection value in the area except the flag can better follow the true phase angle, and the detection accuracy increases with time while the distortion area decreases with time. The voltage drop detection curve is shown in Figure 5 As shown, flag is the voltage drop flag. From the curve, we can see that Nearby flag = 1, that is, the method proposed in the present invention can effectively detect the voltage sag fault.

[0107] Example 2

[0108] Based on the same inventive concept, the present invention also provides a voltage amplitude and phase detection device suitable for voltage sag detection, and the voltage amplitude and phase detection device suitable for voltage sag detection includes:

[0109] A first filtering module, configured to perform a primary filtering on the voltage sampling value of the sampling period to be measured based on the voltage sampling values ​​of the two sampling periods before the sampling period to be measured, so as to obtain a primary filtering value of the sampling period to be measured;

[0110] A second filtering module is used to perform secondary filtering on the primary filtering value of the sampling period to be measured by using a second-order low-pass filter to obtain a secondary filtering value of the sampling period to be measured;

[0111] A third filtering module, used for performing weighted averaging on the primary filtering value and the secondary filtering value of the sampling period to be measured to obtain a weighted average value of the sampling period to be measured;

[0112] A determination module is used to determine the voltage amplitude and phase angle of the sampling period to be measured based on the weighted average value of the sampling period to be measured.

[0113] Preferably, the primary filtering value of the sampling period to be measured is as follows:

[0114]

[0115] In the above formula, is the primary filtering value of the kth sampling period, the kth sampling period is the sampling period to be measured, are the squares of the voltage sampling values ​​of the kth, k-1th, and k-2th sampling periods, respectively, T s is the number of sampling periods, w 0 is the nominal angular frequency of the power grid.

[0116] Furthermore, the secondary filtering value of the sampling period to be measured is as follows:

[0117]

[0118] In the above formula, are the secondary filtering values ​​of the kth, k-1th, and k-2th sampling periods, ξ is the damping coefficient, and w c is the cut-off frequency, They are the primary filtering values ​​of the k-1th and k-2th sampling periods respectively.

[0119] Furthermore, the weighted average value of the sampling period to be measured is as follows:

[0120]

[0121] In the above formula, F(k) is the weighted average value of the kth sampling period, and W(k) is the weight coefficient of the kth sampling period.

[0122] Furthermore, the weight coefficient of the kth sampling period is as follows:

[0123]

[0124] In the above formula, e is a natural constant, β is a preset adjustable parameter, and k d It is the sampling period when the voltage drops.

[0125] Furthermore, the updating process of the sampling period when the voltage drops includes:

[0126] Determine the voltage drop flag of the kth sampling period based on the primary filtering value of the kth sampling period;

[0127] When the voltage drop flag bit of the kth sampling cycle is 1, update k d =k.

[0128] Furthermore, the voltage drop flag of the kth sampling period is as follows:

[0129]

[0130] In the above formula, flag k is the voltage drop flag of the kth sampling period, and α is the voltage drop detection threshold.

[0131] Preferably, the voltage amplitude and phase angle of the sampling period to be measured are as follows:

[0132]

[0133] φ(k)=asin(U(k) / A(k))

[0134] In the above formula, A(k) is the voltage amplitude of the kth sampling period, the kth sampling period is the sampling period to be measured, F(k) is the weighted average value of the kth sampling period, φ(k) is the voltage phase angle of the kth sampling period, and U(k) is the voltage sampling value of the kth sampling period.

[0135] Example 3

[0136] Based on the same inventive concept, the present invention also provides a computer device, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of a voltage amplitude and phase detection method suitable for voltage sag detection in the above embodiment.

[0137] Example 4

[0138] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It can be understood that the computer-readable storage medium here can include both built-in storage media in the computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of a voltage amplitude and phase detection method suitable for voltage sag detection in the above embodiment.

[0139] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0140] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0141] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0142] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A voltage amplitude and phase detection method suitable for voltage sag detection, characterized in that: The method comprises: Based on the voltage sampling values ​​of the two sampling periods before the sampling period to be measured, the voltage sampling value of the sampling period to be measured is filtered once to obtain a primary filtering value of the sampling period to be measured; Using a second-order low-pass filter to perform secondary filtering on the primary filtering value of the sampling period to be measured, to obtain the secondary filtering value of the sampling period to be measured; Performing weighted averaging on the primary filtering value and the secondary filtering value of the sampling period to be measured to obtain a weighted average value of the sampling period to be measured; The voltage amplitude and phase angle of the sampling period to be measured are determined based on the weighted average value of the sampling period to be measured.

2. The method according to claim 1, characterized in that The primary filtering value of the sampling period to be measured is as follows: In the above formula, is the primary filtering value of the kth sampling period, the kth sampling period is the sampling period to be measured, are the squares of the voltage sampling values ​​of the kth, k-1th, and k-2th sampling periods, respectively, T s is the number of sampling periods, w0 is the nominal angular frequency of the power grid.

3. The method according to claim 2, characterized in that The secondary filtering value of the sampling period to be measured is as follows: In the above formula, are the secondary filtering values ​​of the kth, k-1th, and k-2th sampling periods, ξ is the damping coefficient, and w c is the cut-off frequency, They are the primary filtering values ​​of the k-1th and k-2th sampling periods respectively.

4. The method according to claim 3, characterized in that The weighted average value of the sampling period to be measured is as follows: In the above formula, V(k) is the weighted average value of the kth sampling period, and W(k) is the weight coefficient of the kth sampling period.

5. The method according to claim 4, characterized in that The weight coefficient of the kth sampling period is as follows: In the above formula, e is a natural constant, β is a preset adjustable parameter, and k d It is the sampling period when the voltage drops.

6. The method according to claim 5, characterized in that The updating process of the sampling period when the voltage drops includes: Determine the voltage drop flag of the kth sampling period based on the primary filtering value of the kth sampling period; When the voltage drop flag bit of the kth sampling cycle is 1, update k d =k.

7. The method according to claim 6, characterized in that The voltage drop flag bit of the kth sampling period is as follows: In the above formula, flag k is the voltage drop flag of the kth sampling period, and α is the voltage drop detection threshold.

8. The method according to claim 1, characterized in that The voltage amplitude and phase angle of the sampling period to be measured are as follows: φ(k)=asin(U(k) / A(k)) In the above formula, A(k) is the voltage amplitude of the kth sampling period, the kth sampling period is the sampling period to be measured, F(k) is the weighted average value of the kth sampling period, φ(k) is the voltage phase angle of the kth sampling period, and U(k) is the voltage sampling value of the kth sampling period.

9. A voltage amplitude and phase detection device suitable for voltage sag detection, characterized in that: The device comprises: A first filtering module, configured to perform a primary filtering on the voltage sampling value of the sampling period to be measured based on the voltage sampling values ​​of the two sampling periods before the sampling period to be measured, so as to obtain a primary filtering value of the sampling period to be measured; A second filtering module is used to perform secondary filtering on the primary filtering value of the sampling period to be measured by using a second-order low-pass filter to obtain a secondary filtering value of the sampling period to be measured; A third filtering module, used for performing weighted averaging on the primary filtering value and the secondary filtering value of the sampling period to be measured to obtain a weighted average value of the sampling period to be measured; A determination module is used to determine the voltage amplitude and phase angle of the sampling period to be measured based on the weighted average value of the sampling period to be measured.

10. The device according to claim 9, characterized in that The primary filtering value of the sampling period to be measured is as follows: In the above formula, is the primary filtering value of the kth sampling period, the kth sampling period is the sampling period to be measured, are the squares of the voltage sampling values ​​of the kth, k-1th, and k-2th sampling periods, respectively, T s is the number of sampling periods, w0 is the nominal angular frequency of the power grid.

11. The device according to claim 10, characterized in that The secondary filtering value of the sampling period to be measured is as follows: In the above formula, are the secondary filtering values ​​of the kth, k-1th, and k-2th sampling periods, respectively, (is the damping coefficient, w c is the cut-off frequency, They are the primary filtering values ​​of the k-1th and k-2th sampling periods respectively.

12. The device according to claim 11, characterized in that The weighted average value of the sampling period to be measured is as follows: In the above formula, F(k) is the weighted average value of the kth sampling period, and W(k) is the weight coefficient of the kth sampling period.

13. The device according to claim 12, characterized in that The weight coefficient of the kth sampling period is as follows: In the above formula, e is a natural constant, β is a preset adjustable parameter, and k d It is the sampling period when the voltage drops.

14. The device according to claim 13, characterized in that The updating process of the sampling period when the voltage drops includes: Determine the voltage drop flag of the kth sampling period based on the primary filtering value of the kth sampling period; When the voltage drop flag bit of the kth sampling cycle is 1, update k d =k.

15. The device according to claim 14, characterized in that The voltage drop flag bit of the kth sampling period is as follows: In the above formula, flag k is the voltage drop flag of the kth sampling period, and α is the voltage drop detection threshold.

16. The device according to claim 9, characterized in that The voltage amplitude and phase angle of the sampling period to be measured are as follows: φ(k)=asin(U(k) / A(k)) In the above formula, A(k) is the voltage amplitude of the kth sampling period, the kth sampling period is the sampling period to be measured, F(k) is the weighted average value of the kth sampling period, φ(k) is the voltage phase angle of the kth sampling period, and U(k) is the voltage sampling value of the kth sampling period.

17. A computer device, characterized in that: include: one or more processors; The processor is configured to execute one or more programs; When the one or more programs are executed by the one or more processors, the voltage amplitude and phase detection method suitable for voltage sag detection as claimed in any one of claims 1 to 8 is implemented.

18. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the voltage amplitude and phase detection method suitable for voltage sag detection as claimed in any one of claims 1 to 8 is implemented.

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