A low-voltage power distribution network circuit breaker circuit reconstruction design method and system

Abstract

The application discloses a low-voltage distribution network circuit breaker circuit reconstruction design method and system, which comprises the following steps: inputting voltage and current signals into a voltage and current conditioning circuit to convert the signals into signals that can be collected by a first chip; transmitting the collected data to a second chip by the first chip; obtaining a frequency spectrum graph after the second chip processes the data; transforming and reconstructing the frequency spectrum sequence of adjacent points in the frequency spectrum graph by using a multi-point transformation algorithm; correcting the position of the frequency spectrum line by using a spectrum line interpolation method to obtain harmonic amplitude and phase data; transmitting the harmonic amplitude and phase data to serial port software through serial port communication for analysis, so that the harmonic detection of the low-voltage distribution network circuit breaker is realized. The application utilizes FPGA to perform efficient harmonic detection, adopts a multi-point transformation algorithm based on a Hanning window to process the frequency spectrum obtained by FFT, reduces the influence of the fence effect and spectrum leakage, and is helpful to maintain the stable operation of the power system and improve the power quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-voltage power distribution network research, and particularly relates to a low-voltage power distribution network circuit breaker circuit reconstruction design method and system. BACKGROUND

[0002] Low-voltage power distribution network is a key part of the power system that converts high-voltage transmission line power into low-voltage power suitable for end users. With the increase of new energy access and nonlinear load, harmonic pollution is increasingly common in the distribution network, causing serious damage to power quality, manifesting as voltage distortion, temporary drop, and other problems, and may endanger the safety of power generation, power supply and user equipment, also increase network loss, reduce power factor and increase line loss. Therefore, efficient and reasonable harmonic detection and treatment becomes particularly important. As a key node in the distribution network, the low-voltage circuit breaker plays an important role in ensuring the safe and stable operation of the power system. Taking student dormitories as an example, the campus, building and individual dormitories are respectively provided with first, second and third level protection circuit breakers. Although the first level protection has been intelligentized, the second and third level protections have not been intelligentized, which may lead to local fault affecting the stability of power supply of the entire campus. Therefore, improving the intelligent level of the circuit breaker, such as installing harmonic detection devices, is crucial for quickly locating the fault position, avoiding misoperation, and maintaining the stability of the power system.

[0003] Traditional low-voltage circuit breakers rely on mechanical structures for overcurrent, open-phase or leakage protection, and their functions are relatively single. Modern intelligent circuit breakers introduce embedded development, integrated circuits, wireless communication technology, etc., realizing real-time monitoring and processing of power grid signals (such as voltage and current), and transmitting data to analysts or cloud storage through wireless communication. The microprocessors currently used in low-voltage intelligent circuit breakers mainly include ARM, DSP and FPGA. ARM is known for its low power consumption and high performance; DSP is good at high-speed calculation; and FPGA is superior to the former two in speed and safety due to its parallel processing capability and hardware algorithm implementation, and is convenient for circuit structure adjustment and ASIC chip design conversion. Some researches also propose combining 5G NB-IoT wireless communication with intelligent circuit breakers to realize remote control, monitoring and relay protection functions.

[0004] In summary, with the development of power network, especially the application of new energy and the growth of nonlinear load, the influence of harmonic problems on low-voltage distribution network cannot be ignored. Intelligent circuit breakers not only provide more reliable power protection, but also effectively detect and respond to harmonic pollution through the integration of advanced sensing, communication and technology, thereby ensuring the safe and stable operation of the power system. In order to further improve the quality of power service, it is necessary to continue to explore new technologies and new applications of intelligent circuit breakers, especially in the aspect of harmonic detection and treatment, to adapt to the increasingly complex power environment needs. SUMMARY

[0005] In view of the above existing problems, the present application is proposed.

[0006] Therefore, the present application provides a low-voltage power distribution network circuit breaker circuit reconstruction design method and system to solve the problem that traditional circuit breakers lack intelligent harmonic detection and management capabilities, making it difficult to effectively deal with the overall network harmonic pollution caused by the increase of new energy access and nonlinear loads, affecting the stability of the power system and the power quality.

[0007] To solve the above technical problems, the present application provides the following technical solutions:

[0008] In the first aspect, the present application provides a low-voltage power distribution network circuit breaker circuit reconstruction design method, comprising: converting the voltage and current signal input voltage and current conditioning circuit into a signal that can be collected by the first chip; the first chip transmits the collected data to the second chip, and the second chip processes the data to obtain a frequency spectrum; using a multi-point transformation algorithm to transform and reconstruct the frequency spectrum sequence of adjacent points in the frequency spectrum, using a spectral line interpolation method to correct the position of the spectral line, and obtaining harmonic amplitude and phase data; transmitting the harmonic amplitude and phase data to the serial port software for analysis through serial port communication, and realizing harmonic detection of the low-voltage power distribution network circuit breaker.

[0009] As a preferred scheme of the low-voltage power distribution network circuit breaker circuit reconstruction design method of the present application, wherein: the second chip processes the data to obtain a frequency spectrum includes:

[0010] The collected signal is added with a Hanning window;

[0011] The windowed signal is input into the FFT IP core to obtain complex frequency domain data;

[0012] The frequency domain data is taken modulo by the CORDIC IP core to obtain the actual frequency spectrum.

[0013] As a preferred scheme of the low-voltage power distribution network circuit breaker circuit reconstruction design method of the present application, wherein: the time domain expression of the Hanning window is:

[0014]

[0015] Wherein, ω(n) is the window function, N is the sampling length, R N (n) is the time domain expression of the rectangular window;

[0016] The process of adding the Hanning window can be regarded as time domain multiplication, and the windowed signal is:

[0017] x w (n)=x(n)·ω(n)

[0018] where x(n) is the signal before windowing;

[0019] The Fourier transform of the signal after windowing is:

[0020]

[0021] where A0 is the amplitude of the signal, W(ω) is the spectral function of the Hanning window, e -j2πnf is the exponential term of the Fourier transform, j is the imaginary unit, is the initial phase, f is the frequency variable, f0 is the center frequency of the signal, f s is the sampling frequency of the signal.

[0022] As a preferred scheme of the low-voltage distribution network circuit breaker circuit reconstruction design method, the method comprises the following steps:

[0023] When the y-spectral line interpolation method is used, the optimal transformation point number x should satisfy:

[0024]

[0025] where l is the spectral line interval.

[0026] By determining the optimal transformation point number, the five-point transformation is used to obtain the decay rate of the spectral distribution, and the frequency, amplitude and phase of the actual harmonic are obtained by using the parameters of the n=k and n=k+1 spectral lines.

[0027] As a preferred scheme of the low-voltage distribution network circuit breaker circuit reconstruction design method, the method comprises the following steps:

[0028] The transformation ratio of the transformer of the voltage conditioning circuit is 1:1, a large resistance is used at the front end of the voltage conditioning circuit to convert the AC voltage source into a mA-level small AC current, and the mA-level small AC current is converted into the voltage range that can be sampled by the ADC through an operational amplifier;

[0029] The transformation ratio of the transformer of the current conditioning circuit is 1:1000, an A-level large current of the harmonic source is converted into a mA-level small current, and the mA-level small current is converted into the voltage range that can be sampled by the ADC through a bias circuit and an operational amplifier.

[0030] As a preferred scheme of the low-voltage power distribution network circuit breaker circuit reconstruction design method, wherein: the power supply circuit uses a voltage stabilizing tube and an electrolytic capacitor to stabilize the voltage at a fixed value, which is used to bias the voltage and current conditioning circuit.

[0031] As a preferred scheme of the low-voltage power distribution network circuit breaker circuit reconstruction design method, wherein: the first chip transmits the collected data to the second chip includes:

[0032] Confirming that the specification of the first chip meets the transmission standard;

[0033] According to the application requirement and the transmission speed requirement, it is determined to use SPI serial communication or parallel output mode;

[0034] After confirming the transmission mode, the first chip transmits the collected data to the second chip.

[0035] In a second aspect, the present application provides a low-voltage power distribution network circuit breaker circuit reconstruction design system, comprising:

[0036] A signal conversion module is configured to convert the voltage and current signal input into the voltage and current conditioning circuit into a signal that can be collected by the first chip;

[0037] A first processing module is configured to transmit the data collected by the first chip to the second chip, and the second chip processes the data to obtain a frequency spectrum;

[0038] A second processing module is configured to use a multi-point transformation algorithm to transform and reconstruct the frequency spectrum sequence of adjacent points in the frequency spectrum, and use a spectral line interpolation method to correct the position of the spectral line to obtain harmonic amplitude and phase data;

[0039] A monitoring and analysis module is configured to transmit the harmonic amplitude and phase data to the serial port software for analysis through serial port communication, thereby realizing harmonic detection of the low-voltage power distribution network circuit breaker.

[0040] In a third aspect, the present application provides an electronic device, comprising:

[0041] A memory and a processor;

[0042] The memory is configured to store computer executable instructions, and the processor is configured to execute the computer executable instructions, which realize the steps of the low-voltage power distribution network circuit breaker circuit reconstruction design method when executed by the processor.

[0043] In a fourth aspect, the present application provides a computer readable storage medium storing computer executable instructions, which realize the steps of the low-voltage power distribution network circuit breaker circuit reconstruction design method when executed by the processor.

[0044] Compared with the prior art, the low-voltage power distribution network circuit breaker circuit reconstruction design method and system provided by the application has the advantages that: the FPGA is implanted in the intelligent circuit breaker to realize efficient harmonic detection, which not only expands the functions of the traditional intelligent circuit breaker, such as electric parameter measurement, reclosing, residual current protection, overvoltage and undervoltage protection, remote control and communication, but also significantly improves the power quality, especially for the harmonic pollution problem caused by the access of new energy and the increase of nonlinear load. The fast Fourier transform method is used for harmonic detection, which has the advantages of high precision, low system resource consumption and low cost. In order to solve the problem of frequency spectrum leakage caused by the change of power frequency, that is, the influence of non-synchronous sampling on the harmonic frequency accuracy, the application introduces the method of multi-point transformation after adding Hanning window to process the sampling data, which greatly reduces the influence of non-synchronous sampling on the harmonic detection result, and optimizes the frequency spectrum obtained by the Hanning window-based multi-point transformation algorithm, which effectively reduces the influence of the fence effect and the frequency spectrum leakage. The MATLAB simulation results show that the relative error of the algorithm in the harmonic phase and amplitude detection is very small, and the algorithm realized on the FPGA is verified by the harmonic power test to have high precision and effectiveness in harmonic detection, which is helpful to maintain the stable operation of the power system and improve the power quality. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0046] Figure 1 The overall flow logic diagram of the low-voltage power distribution network circuit breaker circuit reconstruction design method described in an embodiment of the application;

[0047] Figure 2 The voltage and current conditioning circuit schematic diagram of the low-voltage power distribution network circuit breaker circuit reconstruction design method described in an embodiment of the application;

[0048] Figure 3 The AD7606 physical diagram of the low-voltage power distribution network circuit breaker circuit reconstruction design method described in an embodiment of the application;

[0049] Figure 4 The AD7606 system block diagram of the low-voltage power distribution network circuit breaker circuit reconstruction design method described in an embodiment of the application;

[0050] Figure 5 The harmonic measurement method flowchart of the low-voltage power distribution network circuit breaker circuit reconstruction design method described in an embodiment of the application. Detailed Implementation

[0051] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0052] Example 1

[0053] Reference Figures 1-5 As one embodiment of the present invention, a method for redesigning and modifying circuits of low-voltage distribution network circuit breakers is provided, such as... Figure 1 The specific steps shown are as follows:

[0054] S100: Inputs voltage and current signals into the voltage and current conditioning circuit and converts them into signals that can be acquired by the first chip;

[0055] S200: The first chip transmits the collected data to the second chip, which processes the data to obtain a spectrum.

[0056] S300: The multi-point transformation algorithm is used to transform and reconstruct the spectral sequence of adjacent points in the spectrum diagram, and the position of the spectral line is corrected by the spectral line interpolation method to obtain the harmonic amplitude and phase data.

[0057] S400: Transmits harmonic amplitude and phase data to serial port software for analysis via serial communication, enabling harmonic detection in low-voltage distribution network circuit breakers.

[0058] It should be noted that the application provides a low-voltage distribution network circuit breaker circuit transformation design method and system, which realizes efficient harmonic detection by implanting FPGA in the intelligent circuit breaker, not only expands the functions of the traditional intelligent circuit breaker, such as electric parameter measurement, reclosing, residual current protection, overvoltage and undervoltage protection, remote control and communication, but also significantly improves the power quality, especially for the harmonic pollution problem caused by the access of new energy and the increase of nonlinear load. The fast Fourier transform method is used for harmonic detection, which has the advantages of high precision, low system resource consumption and low cost. At the same time, in order to solve the problem of frequency spectrum leakage caused by power frequency change, that is, the influence of non-synchronous sampling phenomenon on harmonic frequency accuracy, the application introduces the method of multi-point transformation after adding Hanning window to process the sampling data, which greatly reduces the influence of non-synchronous sampling on the harmonic detection result, and optimizes the frequency spectrum obtained by the FFT based on the multi-point transformation algorithm of Hanning window, effectively reduces the influence of fence effect and spectrum leakage. MATLAB simulation results show that the relative error of the algorithm in harmonic phase and amplitude detection is very small, and the algorithm realized on FPGA is verified by harmonic power test to have high precision and effectiveness in harmonic detection, which helps to maintain the stable operation of the power system and improve the power quality.

[0059] In the embodiment of the application, the step S100 of converting the voltage and current signal input into the voltage and current conditioning circuit into a signal that can be collected by the first chip (AD7606) includes:

[0060] As Figure 2 The voltage and current conditioning circuit schematic diagram is shown, the transformer of the voltage conditioning circuit has a transformation ratio of 1:1, a 300kΩ large resistance is used at the front end of the voltage conditioning circuit to convert the 220V AC voltage source with an effective value into a small AC current of about 0.73mA, and the mA-level small AC current is converted into an ADC-samplable voltage range of 0-3V through an operational amplifier; the transformer of the current conditioning circuit has a transformation ratio of 1:1000, an A-level large current of the harmonic source is converted into an mA-level small current, and the mA-level small current is converted into an ADC-samplable voltage range of 0-3V through a bias circuit and an operational amplifier. The power supply circuit uses a stabilizing tube and an electrolytic capacitor to stabilize the voltage at about 1.25V, which is used to bias the voltage and current conditioning circuit, because the amplitude of the original signal is about-2V-2V, the ADC sampling can only sample positive values, and needs to be biased.

[0061] It should be noted that the step S100 not only protects the sensitive acquisition chip from high voltage and large current, but also improves the accuracy and reliability of data acquisition, lays a solid foundation for subsequent data transmission and processing, enables the entire harmonic detection system to obtain high-quality input signals from the source, and thus guarantees the accuracy and effectiveness of the final analysis results.

[0062] In the embodiment of the present application, the step S200 comprises the following sub-steps B1-B2.

[0063] In B1, the first chip transmits the collected data to the second chip (ZYNQ_7010_FPGA);

[0064] Specifically, the AD7606 used is a 16-bit, 8-channel analog-to-digital converter, which can collect voltage in the range of ±10V and ±5V, and is controlled through the range pin. The sampling rate is 200 kHz, the analog input impedance is 1MΩ, supports SPI communication, and can be output in series or in parallel. The parallel output mode is faster than the serial output mode. In addition, the 8 channels of AD7606 also support the three-phase voltage and current collection of the design.

[0065] It should be noted that the physical diagram of AD7606 is as shown in Figure 3 The system block diagram of AD7606 is as shown in Figure 4 .

[0066] In B2, the second chip obtains a spectrum diagram after processing the data;

[0067] Specifically, the second chip obtains a spectrum diagram after processing the data, which comprises: adding a Hanning window to the collected signal; inputting the windowed signal into the FFT IP core to obtain complex frequency domain data; and taking the frequency domain data through the CORDIC IP core to obtain the actual spectrum diagram.

[0068] Specifically, the time domain expression of the Hanning window is:

[0069]

[0070] where ω(n) is the window function, N is the sampling length, R N (n) is the time domain expression of the rectangular window;

[0071] The process of adding a Hanning window can be regarded as time domain multiplication, so the windowed signal is:

[0072] x w (n)=x(n)·ω(n)

[0073] where x(n) is the signal before windowing;

[0074] The Fourier transform of the windowed signal is:

[0075]

[0076] where A0 is the amplitude of the signal, W(ω) is the frequency spectrum function of the Hanning window, e -j2πnfHere, j represents the exponential term of the Fourier transform, and j is the imaginary unit. Let f be the initial phase, f be the frequency variable, f0 be the center frequency of the signal, and f be the frequency of the signal. s The sampling frequency of the signal;

[0077]

[0078] Among them, W R (ω) represents the Fourier transform of the rectangular window.

[0079] It should be noted that step S200 not only enables rapid data transmission and preliminary processing, but also ensures accurate signal conversion from the time domain to the frequency domain. The system can accurately capture the frequency characteristics of the power signal while maintaining high time resolution, providing clear and detailed spectral information for subsequent in-depth analysis. Step S200 improves the overall efficiency and reliability of the system, laying a solid foundation for accurate harmonic detection of low-voltage distribution network circuit breakers.

[0080] In this embodiment of the application, step S300 above uses a multi-point transformation algorithm to transform and reconstruct the spectral sequence of adjacent points in the spectrum diagram, and uses spectral line interpolation to correct the position of the spectral lines to obtain harmonic amplitude and phase data, including:

[0081] The first step is to determine the number of transformation points, because different types of waveforms often have different optimal numbers of transformation points in actual spectrum analysis. Generally speaking, when using the y-line interpolation method, the optimal number of transformation points x should satisfy:

[0082]

[0083] Where l is the spectral line interval, here l = 5, y = 2, we get x = 5, so we use the five-point transformation formula;

[0084] The five-point transformation formula is shown below:

[0085]

[0086] Where k is the sequence of sampling points, β is equivalent to the gain, and γ is the attenuation coefficient;

[0087] It can be seen that the decay rate of the spectral distribution obtained by the five-point transformation changes from the original 1 / γ to the current 1 / γ(γ) 2 -1)(γ 2 -4), the attenuation rate is greatly improved, so spectral lines that are far from the actual frequency will be suppressed, thereby reducing the spectral leakage component;

[0088] Simultaneously, the frequency, amplitude, and phase of the actual harmonic can also be determined relatively accurately using the parameters of the two spectral lines n=k and n=k+1. The specific method is as follows:

[0089]

[0090] wherein m is the ratio of two adjacent spectral lines, and a is a parameter within the frequency domain expression, 0 < a < 1;

[0091]

[0092] wherein A is the amplitude of the harmonic, and 0 is the phase angle of the harmonic, i i denotes the phase angle of x.

[0093] It should be noted that the above step S300 not only effectively solves the error caused by spectrum leakage and fence effect, but also accurately restores the harmonic component of the original signal, ensures the high accuracy of the harmonic detection result, provides reliable data support for the harmonic analysis of the low-voltage distribution network circuit breaker, enhances the diagnosis ability of the system to the power quality problem, and thus helps to realize more accurate and efficient power quality management.

[0094] In the embodiment of the present application, as shown in Figure 5 The above step S400 transmits the harmonic amplitude and phase data to the serial port software for analysis through serial port communication, realizes the automation and real-time performance of the harmonic detection of the low-voltage distribution network circuit breaker, and the stability and efficiency of the serial port communication ensure the accuracy of data transmission, so that the harmonic analysis can be quickly completed in the special software, thereby providing detailed power quality evaluation in time, not only simplifying the data analysis process, but also providing intuitive and reliable decision support for the operation and maintenance personnel, helping to quickly respond to abnormal situations in the power system and ensure the safe and stable operation of the power grid.

[0095] The above is a schematic scheme of a low-voltage distribution network circuit breaker circuit reconstruction design method of the embodiment. It should be noted that the technical scheme of the low-voltage distribution network circuit breaker circuit reconstruction design system belongs to the same concept as the technical scheme of the low-voltage distribution network circuit breaker circuit reconstruction design method described above, and the technical scheme of the low-voltage distribution network circuit breaker circuit reconstruction design system in the embodiment is not described in detail. The details can be referred to the description of the technical scheme of the low-voltage distribution network circuit breaker circuit reconstruction design method.

[0096] In the embodiment, a low-voltage distribution network circuit breaker circuit reconstruction design system is also provided, comprising:

[0097] The signal conversion module is configured to convert the voltage and current signal input into the voltage and current conditioning circuit into a signal that can be collected by the first chip.

[0098] ​​The first processing module is configured to transmit the collected data to the second chip, and the second chip processes the data to obtain a frequency spectrum diagram;

[0099] The second processing module is configured to transform and reconstruct a frequency spectrum sequence of adjacent points in the frequency spectrum diagram by using a multipoint transformation algorithm, and correct the position of a spectral line by using a spectral line interpolation method to obtain harmonic amplitude and phase data.

[0100] The monitoring and analyzing module is configured to transmit the harmonic amplitude and phase data to serial port software through serial port communication for analysis, so as to realize harmonic detection of the low-voltage power distribution network circuit breaker.

[0101] The above modules can be embedded in or independent of the processor in the computer device in hardware form, or can be stored in the memory in the computer device in software form, so as to call and execute the operations of the above modules by the processor.

[0102] The embodiment also provides an electronic device including a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. The processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is configured to perform wired or wireless communication with an external terminal. The wireless communication can be achieved by WIFI, operator network, NFC (near field communication) or other technologies. The computer program is executed by the processor to implement a low-voltage power distribution network circuit breaker circuit reconstruction design method. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device can be a touch layer overlaid on the display screen, or a key, trackball or touchpad arranged on the shell of the computer device. The input device can also be an external keyboard, touchpad or mouse, etc.

[0103] The embodiment also provides a computer readable storage medium having a computer program stored thereon. The program is executed by the processor to implement the method proposed in the above embodiment.

[0104] The storage medium proposed in the embodiment belongs to the same inventive concept as the method proposed in the above embodiment. The technical details not described in detail in the embodiment can be referred to the above embodiment, and the embodiment has the same beneficial effects as the above embodiment.

[0105] Those skilled in the art can clearly understand that the present application can be implemented by means of software and necessary universal hardware, and of course can also be implemented by hardware, but in many cases the former is a better implementation. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as a floppy disk, a Read Only Memory (ROM), a Random Access Memory (RAM), a FLASH memory, a hard disk, or an optical disc, and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods of the embodiments of the present application.

[0106] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the present application, and all modifications and equivalent replacements should be included in the scope of the claims of the present application.

[0107] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer usable storage media (including but not limited to a magnetic disk storage, a CD-ROM, an optical storage, etc.) containing computer usable program codes. The solutions in the embodiments of the present application can be implemented in various computer languages.

[0108] The present application is described with reference to the flowcharts and / or block diagrams according to the methods, devices (systems), and computer program products of the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices produce a device for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one flow or multiple flows and / or blocks Figure 1 The devices for implementing the functions specified in one flow or multiple flows and / or blocks.

[0109] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the Figure 1 function specified in the flow or flows and / or blocks Figure 1 of the block or blocks.

[0110] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions that are executed on the computer or other programmable apparatus provide steps for implementing the Figure 1 function specified in the flow or flows and / or blocks Figure 1 of the block or blocks.

[0111] Although preferred embodiments of the application have been described herein, substitutions and alterations can be made to these embodiments by those skilled in the art without departing from the spirit and scope of the application. Accordingly, it is intended that the appended claims be interpreted as including all such alternatives and modifications as fall within the spirit and scope of the application.

[0112] It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application cover modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

Claims

1. A low voltage distribution network circuit breaker circuit retrofit design method, characterized by, The method comprises the following steps: The voltage and current signals are converted into signals that can be collected by the first chip through a voltage and current conditioning circuit; The first chip transmits the collected data to the second chip, and the second chip processes the data to obtain a frequency spectrum diagram; The frequency spectrum sequence of adjacent points in the frequency spectrum diagram is transformed and reconstructed by using a multi-point transformation algorithm, the position of the spectral line is corrected by using a spectral line interpolation method, and harmonic amplitude and phase data are obtained; The harmonic amplitude and phase data are transmitted to serial port software through serial port communication for analysis, and harmonic detection of a low-voltage power distribution network circuit breaker is realized; The method that the second chip processes the data to obtain a frequency spectrum diagram comprises the following steps: A Hanning window is added to the collected signal; The windowed signal is input into an FFT IP core to obtain complex frequency domain data; The actual frequency spectrum diagram is obtained by taking the modulus of the frequency domain data through a CORDIC IP core; The time domain expression of the Hanning window is as follows: wherein is a window function, N is a sampling length, is a time domain expression of a rectangular window; The windowed signal is as follows: wherein is the signal before windowing; The Fourier transform of the windowed signal is as follows: wherein is the amplitude of the signal, is the spectral function of a Hanning window, is the exponential term of the Fourier transform, j is the imaginary unit, is the initial phase, f is the frequency variable, is the center frequency of the signal, is the sampling frequency of the signal; The method that the frequency spectrum sequence of adjacent points in the frequency spectrum diagram is transformed and reconstructed by using a multi-point transformation algorithm, and the position of the spectral line is corrected by using a spectral line interpolation method, to obtain harmonic amplitude and phase data comprises the following steps: When using y The optimal number of transform points x Should be satisfied: wherein l is the line spacing; By determining the best transform point number, the five-point transform is used to obtain the decay rate of the spectrum distribution, and the parameters of the two spectral lines n = k and n = k +1 are used to obtain the frequency, amplitude and phase of the actual harmonic.

2. The method of claim 1, wherein the low voltage distribution network circuit retrofit design is for a circuit breaker. The method that the voltage and current signals are converted into signals that can be collected by the first chip through a voltage and current conditioning circuit comprises the following steps: The transformation ratio of the transformer of the voltage conditioning circuit is 1:1, a large resistance is used at the front end of the voltage conditioning circuit to convert an alternating voltage source into a mA-level small alternating current, and the mA-level small alternating current is converted into a voltage range that can be sampled by an ADC through an operational amplifier; The transformation ratio of the transformer of the current conditioning circuit is 1:1000, an A-level large current of a harmonic source is converted into a mA-level small current, and the mA-level small current is converted into a voltage range that can be sampled by an ADC through a bias circuit and an operational amplifier.

3. The low voltage distribution network circuit breaker retrofit design method of claim 2, wherein, A voltage stabilizing tube and an electrolytic capacitor are used in the power supply circuit to stabilize the voltage at a fixed value, which is used to bias the voltage and current conditioning circuit.

4. The low voltage distribution network circuit breaker retrofit design method of claim 3, wherein, The method that the first chip transmits the collected data to the second chip comprises the following steps: It is confirmed that the specifications of the first chip meet the transmission standards; According to the application requirements and transmission speed requirements, it is determined whether to use SPI serial communication or parallel output mode; After confirming the transmission mode, the first chip transmits the collected data to the second chip.

5. A system for low voltage distribution network circuit breaker retrofit design, applying a method for low voltage distribution network circuit breaker retrofit design according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: A signal conversion module is configured to convert voltage and current signals into signals that can be collected by the first chip through a voltage and current conditioning circuit; A first processing module is configured to transmit the collected data to the second chip by the first chip, and the second chip processes the data to obtain a frequency spectrum diagram; A second processing module is configured to transform and reconstruct the frequency spectrum sequence of adjacent points in the frequency spectrum diagram by using a multi-point transformation algorithm, correct the position of the spectral line by using a spectral line interpolation method, and obtain harmonic amplitude and phase data; A monitoring and analysis module is configured to transmit the harmonic amplitude and phase data to serial port software through serial port communication for analysis, and realize harmonic detection of a low-voltage power distribution network circuit breaker.

6. An electronic device, comprising: a memory and a processor; The memory is configured to store computer executable instructions, and the processor is configured to execute the computer executable instructions, and the computer executable instructions, when executed by the processor, implement the steps of the circuit reconstruction design method of the low-voltage distribution network circuit breaker according to any one of claims 1-4. 7.A computer readable storage medium storing computer executable instructions, and the computer executable instructions, when executed by a processor, implement the steps of the circuit reconstruction design method of the low-voltage distribution network circuit breaker according to any one of claims 1-4.

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