Three-phase voltage phase sequence detection method and device under weak power grid

Abstract

The invention relates to a three-phase voltage phase sequence detection method and device under a weak power grid. The method comprises the following steps: acquiring a three-phase voltage instantaneous value of the power grid in real time; based on the three-phase voltage instantaneous value, a first positive phase sequence signal and a first negative phase sequence signal are obtained through static coordinate system conversion and adaptive filtering; performing multi-order discretization orthogonality on the first positive phase sequence signal and the first negative phase sequence signal to obtain a second positive phase sequence signal and a second negative phase sequence signal; calculating a positive phase sequence instantaneous amplitude and a negative phase sequence instantaneous amplitude based on the plurality of phase sequence signals; on the basis of the positive phase sequence amplitudes and the negative phase sequence amplitudes at multiple continuous sampling moments, calculating a weighted average value of the instantaneous amplitude of each phase of voltage; and judging the phase sequence of the power grid according to the weighted average of the instantaneous amplitude of each phase voltage and a corresponding phase sequence judgment threshold. According to the invention, multi-order discretization and multi-time weighting calculation are adopted, so that the phase sequence amplitude can be effectively judged and predicted, and the reliability and accuracy of phase sequence detection are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of weak power grid detection, and in particular relates to a method and device for detecting a three-phase voltage phase sequence in a weak power grid. Background Art

[0002] With the development of energy storage market and technology, the application of industrial and commercial energy storage systems is becoming more and more extensive. Before the energy storage converter is operated, detecting the grid phase sequence is a key step in the self-test process of the energy storage converter. At present, most software phase sequence detection methods convert the three-phase voltage from Ua, Ub and Uc in the static coordinate system to UAlpha and UBeta in the static coordinate system, and judge whether the grid phase sequence is abnormal according to the positive and negative values ​​of UAlpha and UBeta at the zero crossing. As we all know, with the continuous increase in the penetration rate of renewable energy power generation, the power grid in some areas is weakening and the stability is reduced. Under weak grid conditions, in addition to the fluctuation of grid voltage amplitude, nonlinear loads will cause voltage waveform distortion in the AC grid system, and the grid frequency will also produce certain oscillations. Therefore, under weak grid conditions, voltage waveform distortion and grid frequency oscillation may cause misjudgment of the method of using the positive and negative values ​​of UAlpha and UBeta at the zero crossing to determine the grid phase sequence, which will in turn affect the normal operation of industrial and commercial energy storage systems. Summary of the invention

[0003] In order to improve the accuracy and reliability of weak power grid monitoring, a first aspect of the present invention provides a three-phase voltage phase sequence detection method under a weak power grid, including: acquiring the instantaneous value of the three-phase voltage of the power grid in real time; based on the instantaneous value of the three-phase voltage, obtaining a first positive phase sequence signal and a first negative phase sequence signal through static coordinate system conversion and adaptive filtering; performing multi-order discretization and orthogonalization on the first positive phase sequence signal and the first negative phase sequence signal, respectively, to obtain a second positive phase sequence signal and a second negative phase sequence signal; based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal and the second negative phase sequence signal, calculating the positive phase sequence instantaneous amplitude and the negative phase sequence instantaneous amplitude; based on the positive phase sequence amplitude and the negative phase sequence amplitude at multiple consecutive sampling moments, calculating the weighted average value of the instantaneous amplitude of each phase voltage; judging the phase sequence of the power grid according to the weighted average value of the instantaneous amplitude of each phase voltage and the corresponding phase sequence judgment threshold.

[0004] In some embodiments of the present invention, the first positive phase sequence signal and the first negative phase sequence signal are respectively subjected to multi-order discretization orthogonalization to obtain a second positive phase sequence signal and a second negative phase sequence signal, comprising: acquiring the frequency parameters of each phase voltage through a phase voltage phase-locked loop; based on the frequency parameters and a preset transfer function, performing third-order discretization orthogonalization on each phase sequence signal to obtain a second positive phase sequence signal and a second negative phase sequence signal.

[0005] Furthermore, the calculation of the positive phase sequence instantaneous amplitude and the negative phase sequence instantaneous amplitude based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal and the second negative phase sequence signal includes: calculating the first quadrant signal based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal and the second negative phase sequence signal; calculating the second quadrant signal based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal and the second negative phase sequence signal; calculating the positive phase sequence instantaneous amplitude and the negative phase sequence instantaneous amplitude by solving the root mean square of the first quadrant signal and the second quadrant signal.

[0006] In some embodiments of the present invention, the calculation of the weighted average value of the instantaneous amplitude of each phase voltage based on the positive phase sequence amplitude and the negative phase sequence amplitude at multiple consecutive sampling moments includes: determining the weight of the phase sequence amplitude of each phase at each sampling moment; and calculating the weighted average value of the instantaneous amplitude of each phase voltage based on the weight.

[0007] In some embodiments of the present invention, the phase sequence of the power grid is judged according to the weighted average value of the instantaneous amplitude of each phase voltage and the corresponding phase sequence judgment threshold, including: if the weighted average value of the instantaneous amplitude of the positive phase voltage is greater than a first preset value, and the weighted average value of the instantaneous amplitude of the reverse phase voltage is less than a second set value, then the power grid voltage is judged to be a positive phase sequence; if the weighted average value of the instantaneous amplitude of the positive phase voltage is less than the first preset value, and the weighted average value of the instantaneous amplitude of the reverse phase voltage is greater than the second set value, then the power grid voltage is judged to be a positive phase sequence.

[0008] In the above-mentioned embodiment, the first positive phase sequence signal and the first negative phase sequence signal are obtained through static coordinate system conversion and adaptive filtering based on the instantaneous value of the three-phase voltage, including: calculating the modulus and compensation coefficient of the three-phase voltage based on the effective value of the instantaneous value of the three-phase voltage; calculating the three-phase voltage signal according to the modulus and compensation coefficient of the three-phase voltage; and obtaining the first positive phase sequence signal and the first negative phase sequence signal through static coordinate system conversion and adaptive filtering for the three-phase voltage signal.

[0009] The second aspect of the present invention provides a three-phase voltage phase sequence detection device under a weak power grid, including: an acquisition module, used to acquire the instantaneous value of the three-phase voltage of the power grid in real time; based on the instantaneous value of the three-phase voltage, a first positive phase sequence signal and a first negative phase sequence signal are obtained through static coordinate system conversion and adaptive filtering; an orthogonalization module, used to perform multi-order discretization and orthogonalization on the first positive phase sequence signal and the first negative phase sequence signal, respectively, to obtain a second positive phase sequence signal and a second negative phase sequence signal; a calculation module, used to calculate the positive phase sequence instantaneous amplitude and the negative phase sequence instantaneous amplitude based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal and the second negative phase sequence signal; a judgment module, used to calculate the weighted average value of the instantaneous amplitude of each phase voltage based on the positive phase sequence amplitude and the negative phase sequence amplitude at multiple consecutive sampling moments; according to the weighted average value of the instantaneous amplitude of each phase voltage and the corresponding phase sequence judgment threshold, the phase sequence of the power grid is judged.

[0010] The third aspect of the present invention provides an electronic device, comprising: one or more processors; a storage device for storing one or more programs, when the one or more programs are executed by the one or more processors, the one or more processors implement the three-phase voltage phase sequence detection method under a weak power grid provided in the first aspect of the present invention.

[0011] A fourth aspect of the present invention provides a computer-readable medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the three-phase voltage phase sequence detection method under a weak power grid provided in the first aspect of the present invention.

[0012] The beneficial effects of the present invention are: This scheme adopts weighted calculation of three voltage calculation amplitudes, and the weight increases according to the number of sampling times. The weights of the first two times are low, and the weight of the most recent time is the largest. Multiple sampling weighted calculation is adopted. Such a design can take the amplitudes of the previous two calculations as a reference and focus on the most recent sampling value. Thus, effective judgment and prediction of the phase sequence amplitude can be made, thereby avoiding the occurrence of misjudgment and greatly improving the reliability and accuracy of phase sequence detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a basic flow chart of a method for detecting a three-phase voltage phase sequence in a weak power grid in some embodiments of the present invention; Figure 2 It is a schematic diagram of the transfer function and adaptive filtering principle of the three-phase voltage phase sequence detection method under weak power grid in some embodiments of the present invention; Figure 3 It is a schematic diagram of the principle of a method for detecting a phase sequence of a three-phase voltage in a weak power grid in some embodiments of the present invention; Figure 4It is a structural schematic diagram of a three-phase voltage phase sequence detection device under a weak power grid in some embodiments of the present invention; Figure 5 It is a schematic diagram of the structure of an electronic device in some embodiments of the present invention. DETAILED DESCRIPTION

[0014] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0015] refer to Figure 1 and Figure 3 In the first aspect of the present invention, a three-phase voltage phase sequence detection method under a weak power grid is provided, comprising: S100. acquiring the instantaneous value of the three-phase voltage of the power grid in real time; based on the instantaneous value of the three-phase voltage, obtaining a first positive phase sequence signal and a first negative phase sequence signal through static coordinate system conversion and adaptive filtering; S200. performing multi-order discretization and orthogonalization on the first positive phase sequence signal and the first negative phase sequence signal respectively, to obtain a second positive phase sequence signal and a second negative phase sequence signal; S300. calculating the instantaneous amplitude of the positive phase sequence and the instantaneous amplitude of the negative phase sequence based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal and the second negative phase sequence signal; S400. calculating the weighted average value of the instantaneous amplitude of each phase voltage based on the positive phase sequence amplitude and the negative phase sequence amplitude at multiple consecutive sampling moments; judging the phase sequence of the power grid according to the weighted average value of the instantaneous amplitude of each phase voltage and the corresponding phase sequence judgment threshold.

[0016] In step S100 of some embodiments of the present invention, obtaining the first positive phase sequence signal and the first negative phase sequence signal through static coordinate system conversion and adaptive filtering based on the instantaneous value of the three-phase voltage includes: S101. Calculate the modulus and compensation coefficient of the three-phase voltage based on the effective value of the instantaneous value of the three-phase voltage; S102. Calculate the three-phase voltage signal according to the modulus and compensation coefficient of the three-phase voltage; Specifically, the energy storage system converter hardware circuit processes the grid phase voltage signal through the voltage divider conditioning circuit to obtain a low-voltage AC analog signal. The energy storage converter controller samples and calculates the instantaneous values ​​of the three-phase voltages Ua, Ub and Uc in real time according to the switching frequency, and further obtains the three-phase voltage signals kaUa, kbUb and kcUc, where ka, kb and kc are phase sequence amplitude compensation coefficients respectively; Let the voltage modulus be Um, the effective value of phase A be Uarms, the effective value of phase B be Ubrms, and the effective value of phase C be Ucrms, then ; The phase sequence amplitude compensation coefficient is calculated as follows: If Uarms>Um, then the phase sequence amplitude compensation coefficient of phase A is , if Uarms < Um, then the phase sequence amplitude compensation coefficient of phase A ; Similarly, obtain the phase sequence amplitude compensation coefficients of phase B and phase C.

[0017] S103. For the three-phase voltage signals, obtain the first positive phase sequence signal and the first negative phase sequence signal through static coordinate system transformation and adaptive filtering.

[0018] Specifically, the three-phase voltages are transformed from kaUa, kbUb, and kcUc in the static coordinate system to UAlpha and UBeta in the static coordinate system, and low-delay frequency adaptive filtering is performed to obtain the signals UAlphaT / UBetaT. Further, based on UAlphaT / UBetaT, through a third-order discretized orthogonal strategy, signals UAlphaTQ / UBetaTQ with a phase angle strictly lagging behind UAlphaT / UBetaT by 90° are obtained respectively. Then: , It can be understood that Figure 2 shows that low-delay frequency adaptive filtering is performed on each phase voltage Ux respectively, and the output signals UxT and UxTQ are sine waves. Therefore, the influence of input signal distortion on the phase sequence determination strategy can be eliminated.

[0019] Reference Figure 2 , in step S200 of some embodiments of the present invention, the multi-order discretized orthogonalization of the first positive phase sequence signal and the first negative phase sequence signal respectively to obtain the second positive phase sequence signal and the second negative phase sequence signal includes: S201. Obtain the frequency parameter of each phase voltage through a phase voltage phase-locked loop; Specifically, the above Figure 2 has the frequency parameter of the input signal Ux, which can adapt to the real-time change of the signal frequency, has strong adaptability, and the frequency parameter frequency of each phase voltage is obtained in real time by the software phase voltage phase-locked loop SPLL; S202. Based on the frequency parameter and the preset transfer function, perform third-order discretized orthogonalization on each phase sequence signal to obtain the second positive phase sequence signal and the second negative phase sequence signal.

[0020] Specifically, particularly, perform third-order discretization on G(s)=1 / s. The discretization equation of the specific transfer function is as follows: , is the signal sampling period.

[0021] It should be noted that the transfer-related parameters Q(n) and T(n) in the third-order discretization can be specifically determined according to parameters such as the frequency and amplitude of the filter; as for the order of the filter, the computational cost and accuracy can also be considered comprehensively.

[0022] In step S300 of some embodiments of the present invention, the calculating of the positive phase sequence instantaneous amplitude and the negative phase sequence instantaneous amplitude based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal and the second negative phase sequence signal comprises: S301. Calculate the first quadrant signal based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal and the second negative phase sequence signal; S302. Calculate the second quadrant signal based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal and the second negative phase sequence signal; Specifically, the UAlphaT / UBetaT signal and the orthogonalized signal UAlphaTQ / UBetaTQ are calculated to obtain UAlphaTP / UBetaTP and UAlphaTN / UBetaTN, respectively, as follows: , , , ; k It is the signal average equalization coefficient, which is usually 0.5.

[0023] S303. Calculate the positive phase sequence instantaneous amplitude and the negative phase sequence instantaneous amplitude by solving the root mean square of the first quadrant signal and the second quadrant signal.

[0024] Specifically, based on the UAlphaTP / UBetaTP and UAlphaTN / UBetaTN signals, the energy storage converter calculates the positive phase sequence and the negative phase sequence amplitudes. The specific formula is: , , .

[0025] In step S400 of some embodiments of the present invention, the step of calculating the weighted average value of the instantaneous amplitude of each phase voltage based on the positive phase sequence amplitude and the negative phase sequence amplitude at a plurality of consecutive sampling moments includes: S401. Determine the weight of the phase sequence amplitude of each phase at each sampling moment; Specifically, the energy storage converter control software calculates the positive phase sequence and negative phase sequence amplitudes at three sampling moments. The weights are distributed as follows: .

[0026] S402. Calculate the weighted average value of the instantaneous amplitude of each phase voltage according to the weight.

[0027] Specifically, based on At three sampling moments, each sampling interval is one power frequency cycle, and the weighted average value of the instantaneous amplitude of each phase voltage is calculated as follows: , .

[0028] In step S400 of some embodiments of the present invention, judging the phase sequence of the power grid according to the weighted average value of the instantaneous amplitude of each phase voltage and the corresponding phase sequence judgment threshold comprises: S403. If the weighted average value of the instantaneous amplitude of the positive phase voltage is greater than the first preset value, and the weighted average value of the instantaneous amplitude of the reverse phase voltage is less than the second set value, it is determined that the grid voltage is a positive phase sequence; Specifically, if the weighted average of any positive phase sequence amplitude Greater than the positive sequence judgment threshold , and the weighted average of the reverse phase sequence amplitude Less than the reverse phase sequence judgment threshold , then it can be reliably determined that the grid voltage is in positive phase sequence; It is 0.9 times the voltage modulus, that is, 0.9Um. It is 0.1 times of the voltage modulus, i.e. 0.1Um; S404. If the weighted average value of the instantaneous amplitude of the positive phase voltage is less than the first preset value, and the weighted average value of the instantaneous amplitude of the reverse phase voltage is greater than the second preset value, it is determined that the grid voltage is in a positive phase sequence.

[0029] Specifically, if the weighted average of any positive phase sequence amplitude Less than the positive sequence judgment threshold , and the weighted average of the reverse phase sequence amplitude Greater than the reverse phase sequence judgment threshold , it can be reliably determined that the grid voltage is in positive phase sequence.

[0030] It can be understood that the positive phase sequence and negative phase sequence amplitude judgment strategy adopted in the present disclosure can avoid the misjudgment that occurs in the method of using the positive and negative values ​​of UAlpha and UBeta at the zero crossing to judge the phase sequence of the power grid; The positive phase sequence and reverse phase sequence amplitude judgment strategy is adopted to effectively avoid the influence of voltage imbalance on phase sequence judgment; the positive phase sequence and reverse phase sequence amplitude judgment strategy is adopted to effectively avoid the influence of voltage signal distortion / amplitude change / frequency change on phase sequence; the frequency parameter of the input signal Ux can adapt to the frequency change of the grid phase voltage signal, has strong adaptability, and removes the influence of frequency instability on judgment; the frequency parameter frequency of each phase voltage is obtained in real time by the software phase-locked loop SPLL to obtain the real voltage frequency; the controller performs low-latency adaptive filtering on each phase voltage Ux respectively, and the output signals UxT and UxTQ are sinusoidal waves, which can eliminate the influence of grid voltage signal distortion on judgment; Compared with the low-order discretization method of forward difference / backward difference / bilinear transformation, the third-order discretization method adopted in this scheme can make UxT and UxTQ have strict orthogonal characteristics, thereby ensuring the accuracy of the amplitude calculation of the positive phase sequence and the reverse phase sequence; This scheme adopts weighted calculation of three voltage calculation amplitudes, and the weight increases according to the number of sampling times. The weights of the first two times are low, and the weight of the most recent time is the largest. Multiple sampling weighted calculation is adopted. Such a design can take the amplitudes of the previous two calculations as a reference and focus on the most recent sampling value. Thus, effective judgment and prediction of the phase sequence amplitude can be made, thereby avoiding the occurrence of misjudgment and greatly improving the reliability and accuracy of phase sequence detection.

[0031] Example 2 refer to Figure 4 According to a second aspect of the present invention, a three-phase voltage phase sequence detection device 1 under a weak power grid is provided, comprising: an acquisition module 11, used for acquiring the instantaneous value of the three-phase voltage of the power grid in real time; based on the instantaneous value of the three-phase voltage, a first positive phase sequence signal and a first negative phase sequence signal are obtained through static coordinate system conversion and adaptive filtering; an orthogonalization module 12, used for performing multi-order discretization orthogonalization on the first positive phase sequence signal and the first negative phase sequence signal, respectively, to obtain a second positive phase sequence signal and a second negative phase sequence signal; a calculation module 13, used for calculating the positive phase sequence instantaneous amplitude and the negative phase sequence instantaneous amplitude based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal and the second negative phase sequence signal; a judgment module 14, used for calculating the weighted average value of the instantaneous amplitude of each phase voltage based on the positive phase sequence amplitude and the negative phase sequence amplitude at multiple consecutive sampling moments; the phase sequence of the power grid is judged according to the weighted average value of the instantaneous amplitude of each phase voltage and the corresponding phase sequence judgment threshold.

[0032] Furthermore, the orthogonalization module 12 includes: an acquisition unit, used to obtain the frequency parameters of each phase voltage through a phase voltage phase-locked loop; a discrete unit, used to perform third-order discretization orthogonalization on each phase sequence signal based on the frequency parameters and a preset transfer function to obtain a second positive phase sequence signal and a second negative phase sequence signal.

[0033] Example 3 refer to Figure 5 According to a third aspect of the present invention, an electronic device is provided, comprising: one or more processors; a storage device for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the three-phase voltage phase sequence detection method under a weak power grid according to the first aspect of the present invention.

[0034] The electronic device 500 may include a processing device (e.g., a central processing unit, a graphics processing unit, etc.) 501, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 502 or a program loaded from a storage device 508 into a random access memory (RAM) 503. In the RAM 503, various programs and data required for the operation of the electronic device 500 are also stored. The processing device 501, the ROM 502, and the RAM 503 are connected to each other via a bus 504. An input / output (I / O) interface 505 is also connected to the bus 504.

[0035] Typically, the following devices may be connected to the I / O interface 505: an input device 506 including, for example, a touch screen, a touch pad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; an output device 507 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 508 including, for example, a hard disk, etc.; and a communication device 509. The communication device 509 may allow the electronic device 500 to communicate with other devices wirelessly or by wire to exchange data. Although Figure 5 The electronic device 500 is shown with various devices, but it should be understood that it is not required to implement or possess all the devices shown. More or fewer devices may be implemented or possessed instead. Figure 5 Each block shown in the figure may represent one device, or may represent multiple devices as required.

[0036] In particular, according to an embodiment of the present disclosure, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present disclosure includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through a communication device 509, or installed from a storage device 508, or installed from a ROM 502. When the computer program is executed by the processing device 501, the above functions defined in the method of the embodiment of the present disclosure are executed. It should be noted that the computer-readable medium described in the embodiment of the present disclosure can be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to, an electrical connection with one or more conductors, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In an embodiment of the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, an apparatus, or a device. In an embodiment of the present disclosure, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, in which a computer-readable program code is carried. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in combination with an instruction execution system, an apparatus, or a device. The program code embodied on the computer readable medium may be transmitted using any appropriate medium, including but not limited to: wire, optical cable, RF (radio frequency), etc., or any suitable combination of the foregoing.

[0037] The computer-readable medium may be included in the electronic device, or may exist independently without being installed in the electronic device. The computer-readable medium carries one or more computer programs. When the one or more programs are executed by the electronic device, the electronic device: Computer program code for performing the operations of embodiments of the present disclosure may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages, such as Java, Smalltalk, C++, Python, and conventional procedural programming languages, such as "C" or similar programming languages. The program code may be executed entirely on a user's computer, partially on a user's computer, as a separate software package, partially on a user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0038] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present disclosure. In this regard, each box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A three-phase voltage phase sequence detection method under a weak power grid, characterized in that: include: Acquire the instantaneous value of the three-phase voltage of the power grid in real time; based on the instantaneous value of the three-phase voltage, obtain the first positive phase sequence signal and the first negative phase sequence signal through static coordinate system conversion and adaptive filtering; Performing multi-order discretization orthogonalization on the first positive phase sequence signal and the first negative phase sequence signal respectively to obtain a second positive phase sequence signal and a second negative phase sequence signal; Calculate the positive phase sequence instantaneous amplitude and the negative phase sequence instantaneous amplitude based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal and the second negative phase sequence signal; Based on the positive phase sequence amplitude and the negative phase sequence amplitude at multiple consecutive sampling moments, the weighted average value of the instantaneous amplitude of each phase voltage is calculated; according to the weighted average value of the instantaneous amplitude of each phase voltage and the corresponding phase sequence judgment threshold, the phase sequence of the power grid is judged.

2. The three-phase voltage phase sequence detection method under weak power grid according to claim 1 is characterized in that: The step of performing multi-order discretization orthogonalization on the first positive phase sequence signal and the first negative phase sequence signal to obtain the second positive phase sequence signal and the second negative phase sequence signal comprises: The frequency parameter of each phase voltage is obtained through a phase voltage phase-locked loop; Based on the frequency parameter and the preset transfer function, the phase sequence signal of each phase is subjected to third-order discretization orthogonalization to obtain a second positive phase sequence signal and a second negative phase sequence signal.

3. The three-phase voltage phase sequence detection method under weak power grid according to claim 1 is characterized in that: The calculating of the positive phase sequence instantaneous amplitude and the negative phase sequence instantaneous amplitude based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal and the second negative phase sequence signal comprises: Calculating a first quadrant signal based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal, and the second negative phase sequence signal; Calculating a second quadrant signal based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal, and the second negative phase sequence signal; By solving the root mean square of the first quadrant signal and the second quadrant signal, the positive phase sequence instantaneous amplitude and the negative phase sequence instantaneous amplitude are calculated.

4. The three-phase voltage phase sequence detection method under weak power grid according to claim 1 is characterized in that: The step of calculating the weighted average value of the instantaneous amplitude of each phase voltage based on the positive phase sequence amplitude and the negative phase sequence amplitude at a plurality of consecutive sampling moments comprises: Determine the weight of the phase sequence amplitude of each phase at each sampling moment; According to the weights, a weighted average value of the instantaneous amplitude of each phase voltage is calculated.

5. The three-phase voltage phase sequence detection method under weak power grid according to claim 1 is characterized in that: The determining of the phase sequence of the power grid according to the weighted average value of the instantaneous amplitude of each phase voltage and the corresponding phase sequence determination threshold value comprises: If the weighted average value of the instantaneous amplitude of the positive phase voltage is greater than the first preset value, and the weighted average value of the instantaneous amplitude of the reverse phase voltage is less than the second preset value, it is determined that the grid voltage is in a positive phase sequence; If the weighted average value of the instantaneous amplitude of the positive phase voltage is less than the first preset value, and the weighted average value of the instantaneous amplitude of the reverse phase voltage is greater than the second preset value, it is determined that the grid voltage is in a positive phase sequence.

6. The three-phase voltage phase sequence detection method under weak power grid according to claim 1 is characterized in that: The method of obtaining the first positive phase sequence signal and the first negative phase sequence signal based on the instantaneous value of the three-phase voltage by static coordinate system conversion and adaptive filtering includes: Calculating the modulus and compensation coefficient of the three-phase voltage based on the effective value of the instantaneous value of the three-phase voltage; Calculate the three-phase voltage signal according to the modulus value and compensation coefficient of the three-phase voltage; For the three-phase voltage signal, a first positive phase sequence signal and a first negative phase sequence signal are obtained through static coordinate system conversion and adaptive filtering.

7. A three-phase voltage phase sequence detection device under weak power grid, characterized in that: include: An acquisition module is used to acquire the instantaneous value of the three-phase voltage of the power grid in real time; based on the instantaneous value of the three-phase voltage, a first positive phase sequence signal and a first negative phase sequence signal are obtained through static coordinate system conversion and adaptive filtering; An orthogonalization module is used to perform multi-order discretization orthogonalization on the first positive phase sequence signal and the first negative phase sequence signal to obtain a second positive phase sequence signal and a second negative phase sequence signal; A calculation module, used for calculating the positive phase sequence instantaneous amplitude and the negative phase sequence instantaneous amplitude based on the first positive phase sequence signal, the first negative phase sequence signal, the second positive phase sequence signal and the second negative phase sequence signal; The judgment module is used to calculate the weighted average value of the instantaneous amplitude of each phase voltage based on the positive phase sequence amplitude and the reverse phase sequence amplitude at multiple consecutive sampling moments; and judge the phase sequence of the power grid according to the weighted average value of the instantaneous amplitude of each phase voltage and the corresponding phase sequence judgment threshold.

8. The three-phase voltage phase sequence detection device under weak power grid according to claim 7, characterized in that: The orthogonalization module comprises: An acquisition unit, used for acquiring a frequency parameter of each phase voltage through a phase voltage phase-locked loop; The discrete unit is used to perform third-order discretization orthogonalization on the phase sequence signal of each phase based on the frequency parameter and the preset transfer function to obtain a second positive phase sequence signal and a second negative phase sequence signal.

9. An electronic device, comprising: one or more processors; A storage device for storing one or more programs, when the one or more programs are executed by the one or more processors, enables the one or more processors to implement the three-phase voltage phase sequence detection method under a weak power grid as described in any one of claims 1 to 6.

10. A computer readable medium having a computer program stored thereon, wherein: When the computer program is executed by a processor, the method for detecting the phase sequence of three-phase voltage in a weak power grid as described in any one of claims 1 to 6 is implemented.

Images