Circuit transformation design method and system for low-voltage distribution network circuit breaker

Abstract

The invention discloses a circuit transformation design method and system for a low-voltage power distribution network circuit breaker. The method comprises the steps that voltage and current signals are input into a voltage and current conditioning circuit to be converted into signals capable of being collected by a first chip; the first chip transmits the collected data to the second chip, and the second chip processes the data to obtain a spectrogram; performing transformation and reconstruction on a spectrum sequence of adjacent points in the spectrogram by using a multi-point transformation algorithm, and correcting the position of a spectrum line by using a spectrum line interpolation method to obtain harmonic amplitude phase data; and transmitting the harmonic amplitude phase data to serial port software for analysis through serial port communication, thereby realizing harmonic detection of the low-voltage power distribution network circuit breaker. According to the invention, efficient harmonic detection is carried out by using the FPGA, and the frequency spectrum obtained by FFT is processed by using the multi-point transformation algorithm based on the Hanning window, so that the influence of the fence effect and the frequency spectrum leakage is reduced, the stable operation of a power system is maintained, and the electric energy quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of low-voltage distribution network research, and in particular to a circuit reconstruction design method and system for a circuit breaker in a low-voltage distribution network. Background Art

[0002] The low-voltage distribution network is a key part of the power system that converts the electric energy of the high-voltage transmission line into low-voltage electric energy suitable for end users. With the access of new energy and the increase of nonlinear loads, harmonic pollution is becoming more and more common in the distribution network, causing serious damage to the quality of power, manifested as voltage distortion, temporary sag and other problems, and may endanger the safety of power generation, power supply and user equipment, and increase network losses, reduce power factor and increase line losses. Therefore, efficient and reasonable harmonic detection and control become particularly important. As a key node in the distribution network, low-voltage circuit breakers play an important role in ensuring the safe and stable operation of the power system. Taking student dormitories as an example, the campus, building and personal dormitory are equipped with primary, secondary and tertiary protection circuit breakers respectively. Although the primary protection has been intelligentized, the secondary and tertiary protections have not yet been intelligentized, which may cause local faults to affect the power supply stability of the entire campus. Therefore, improving the intelligence level of circuit breakers, such as installing harmonic detection devices, is crucial to quickly locate the fault location, avoid accidental power outages, and maintain the stability of the power system.

[0003] Traditional low-voltage circuit breakers rely on mechanical structures for overcurrent, phase failure or leakage protection, and their functions are relatively simple. Modern intelligent circuit breakers have introduced embedded development, integrated circuits, wireless communication technologies, etc., to achieve real-time monitoring and processing of power grid signals (such as voltage and current), and transmit data to analysts or cloud storage through wireless communication. The microprocessors currently used for 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 computing; and FPGA is superior to the former two in speed and security due to its parallel processing capabilities and hardware algorithm implementation characteristics, and it is convenient for circuit structure adjustment and ASIC chip design conversion. Some studies have also proposed combining 5G NB-IoT wireless communication with intelligent circuit breakers to achieve functions such as remote control, monitoring and relay protection.

[0004] In summary, with the development of power networks, especially the application of new energy and the growth of nonlinear loads, the impact of harmonic problems on low-voltage distribution networks cannot be ignored. Intelligent circuit breakers can not only provide more reliable power protection, but also effectively detect and respond to harmonic pollution by integrating 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 services, it is necessary to continue to explore new technologies and new applications of intelligent circuit breakers, especially in harmonic detection and governance, to meet the needs of the increasingly complex power environment. Summary of the invention

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

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

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

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

[0009] As a preferred solution of the low-voltage distribution network circuit breaker circuit reconstruction design method of the present invention, wherein: the second chip processes the data to obtain a spectrum diagram including:

[0010] Add a Hanning window to the collected signal;

[0011] Input the windowed signal into the FFT IP core to obtain frequency domain data in complex form;

[0012] The frequency domain data is modulo-modulated by the CORDIC IP core to obtain an actual spectrum diagram.

[0013] As a preferred solution of the low-voltage distribution network circuit breaker circuit reconstruction design method described in the present invention, the time domain expression of the Hanning window is:

[0014]

[0015] Among them, 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 signal after the windowing is:

[0017] x w (n) = x(n)·ω(n)

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

[0019] The Fourier transform of the windowed signal is:

[0020]

[0021] Among them, A0 is the amplitude of the signal, W(ω) is the spectrum function of the Hanning window, e -j2πnf is the exponential term of 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 solution of the circuit reconstruction design method of the low-voltage distribution network circuit breaker of the present invention, wherein: the spectrum sequence of adjacent points in the spectrum diagram is transformed and reconstructed using a multi-point transformation algorithm, and the position of the spectrum line is corrected using a spectrum line interpolation method to obtain harmonic amplitude and phase data, including:

[0023] When using the y-spectral line interpolation method, the optimal number of transformation points x should satisfy:

[0024]

[0025] Where, l is the spectral line spacing;

[0026] By determining the optimal number of transformation points, a five-point transformation is used to obtain the attenuation rate of the spectrum distribution. At the same time, the parameters of the two spectrum lines n=k and n=k+1 are used to calculate the frequency, amplitude and phase of the actual harmonics.

[0027] As a preferred solution of the low-voltage distribution network circuit breaker circuit modification design method described in the present invention, wherein: the step of converting the voltage and current signals input into the voltage and current conditioning circuit into signals that can be collected by the first chip includes:

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

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

[0030] As a preferred solution of the low-voltage distribution network circuit breaker circuit modification design method described in the present invention, the power supply circuit uses a voltage regulator 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 solution of the low-voltage distribution network circuit breaker circuit modification design method of the present invention, wherein: the first chip transmits the collected data to the second chip including:

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

[0033] Decide whether to use SPI serial communication or parallel output mode based on application requirements and transmission speed requirements;

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

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

[0036] A signal conversion module, used for converting the voltage and current signals input into the voltage and current conditioning circuit into signals that can be collected by the first chip;

[0037] A first processing module, configured for the first chip to transmit the collected data to the second chip, and the second chip to process the data to obtain a spectrum diagram;

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

[0039] The monitoring and analysis module is used to transmit the harmonic amplitude and phase data to the serial port software through serial port communication for analysis, so as to realize harmonic detection of the low-voltage distribution network circuit breaker.

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

[0041] Memory and processor;

[0042] The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the low-voltage distribution network circuit breaker circuit reconstruction design method are implemented.

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

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides a circuit modification design method and system for a low-voltage distribution network circuit breaker, which realizes efficient harmonic detection by implanting FPGA in the intelligent circuit breaker, not only expanding the functions of the traditional intelligent circuit breaker, such as electrical parameter measurement, reclosing, residual current protection, over-voltage and under-voltage protection, remote control and communication, but also significantly improving the quality of electric energy, especially for the harmonic pollution problems caused by the access of new energy sources and the increase of nonlinear loads. The fast Fourier transform method is used for harmonic detection because of its high precision and low embedded system resource consumption and low cost. At the same time, in order to solve the spectrum leakage problem caused by the change of power grid power frequency, that is, the influence of asynchronous sampling on harmonic frequency accuracy, the present invention introduces a multi-point transformation method after adding Hanning window to process the sampling data, which greatly reduces the influence of asynchronous sampling on the harmonic detection results, and optimizes the spectrum obtained by FFT through a multi-point transformation algorithm based on Hanning window, effectively reducing 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. The algorithm was finally implemented on FPGA, and its high-precision characteristics and effectiveness in harmonic detection were verified by harmonic power supply test, which helps to maintain the stable operation of the power system and improve the power quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0046] Figure 1 A schematic diagram of the overall process logic of a method for designing a circuit modification of a low-voltage distribution network circuit breaker according to an embodiment of the present invention;

[0047] Figure 2 A schematic diagram of a voltage and current conditioning circuit of a low-voltage distribution network circuit breaker circuit modification design method according to an embodiment of the present invention;

[0048] Figure 3 A physical picture of AD7606 of a low-voltage distribution network circuit breaker circuit reconstruction design method according to an embodiment of the present invention;

[0049] Figure 4 The AD7606 system block diagram of the low-voltage distribution network circuit breaker circuit modification design method according to one embodiment of the present invention;

[0050] Figure 5 The present invention is a flowchart of a harmonic measurement method of a low-voltage distribution network circuit breaker circuit modification design method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0052] Example 1

[0053] Reference Figure 1-Figure 5 As an embodiment of the present invention, a method for designing circuit reconstruction of a circuit breaker in a low voltage distribution network is provided, such as Figure 1 The specific steps shown include:

[0054] S100: Inputting the voltage and current signals into the voltage and current conditioning circuit to convert them into signals that can be collected by the first chip;

[0055] S200: The first chip transmits the collected data to the second chip, and the second chip processes the data to obtain a spectrum diagram;

[0056] S300: transform and reconstruct the spectrum sequence of adjacent points in the spectrum diagram using a multi-point transformation algorithm, and correct the position of the spectrum line using a spectrum line interpolation method to obtain harmonic amplitude and phase data;

[0057] S400: The harmonic amplitude and phase data are transmitted to the serial port software for analysis through serial port communication to realize harmonic detection of low-voltage distribution network circuit breakers.

[0058] It should be noted that the present invention provides a circuit modification design method and system for a low-voltage distribution network circuit breaker. By implanting an FPGA in an intelligent circuit breaker to achieve efficient harmonic detection, it not only expands the functions of traditional intelligent circuit breakers, such as electrical parameter metering, reclosing, residual current protection, over-voltage and under-voltage protection, remote control and communication, but also significantly improves the quality of electric energy, especially for the harmonic pollution problems caused by the access of new energy sources and the increase of nonlinear loads. The fast Fourier transform method is used for harmonic detection because of its high precision and low embedded system resource consumption and low cost. At the same time, in order to solve the spectrum leakage problem caused by the change of power grid power frequency, that is, the influence of asynchronous sampling on the harmonic frequency accuracy, the present invention introduces a multi-point transformation method after adding a Hanning window to process the sampling data, which greatly reduces the influence of asynchronous sampling on the harmonic detection results, and optimizes the spectrum obtained by FFT through a multi-point transformation algorithm based on the Hanning window, effectively reducing the influence of the 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. The algorithm was finally implemented on FPGA, and its high-precision characteristics and effectiveness in harmonic detection were verified by harmonic power supply test, which helps to maintain the stable operation of the power system and improve the power quality.

[0059] In the embodiment of the present application, the above step S100 converts 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) including:

[0060] like Figure 2 The figure shows the schematic diagram of the voltage and current conditioning circuit. The transformer ratio of the voltage conditioning circuit is 1:1. A 300kΩ large resistor is used at the front end of the voltage conditioning circuit to convert the effective value of the 220V AC voltage source into a small AC current of about 0.73mA. The mA-level small AC current is converted into a voltage range of 0 to 3V that can be sampled by the ADC through the operational amplifier. The transformer ratio of the current conditioning circuit is 1:1000, which converts the A-level large current of the harmonic source into a mA-level small current, and then converts the mA-level small current into a voltage range of 0 to 3V that can be sampled by the ADC through the bias circuit and the operational amplifier. The power supply circuit uses a voltage regulator 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 to 2V, the ADC sampling can generally only sample positive values, which needs to be biased.

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

[0062] In the embodiment of the present application, the above step S200 includes 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. The voltage range that can be collected is ±10V and ±5V. It is controlled by the range pin, the sampling rate is 200kHz, the analog input impedance is 1MΩ, and it supports SPI communication. It can output serially or in parallel. The parallel output mode is faster than the serial output. In addition, the 8 channels of AD7606 also support the three-phase voltage and current acquisition of this design.

[0065] It should be noted that the physical picture of AD7606 is as follows Figure 3 As shown, the system block diagram of AD7606 is as follows Figure 4 shown.

[0066] In B2: the second chip processes the data to obtain a spectrum diagram;

[0067] Specifically, the second chip processes the data to obtain a spectrum diagram, including: adding a Hanning window to the collected signal; inputting the windowed signal into the FFT IP core to obtain frequency domain data in complex form; and taking the frequency domain data modulo the CORDIC IP core to obtain the actual spectrum diagram.

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

[0069]

[0070] Among them, 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 the Hanning window can be regarded as time domain multiplication, and the signal after adding the window 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] Among them, A0 is the amplitude of the signal, W(ω) is the spectrum function of the Hanning window, e -j2πnfis the exponential term of 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;

[0077]

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

[0079] It should be noted that the above step S200 not only realizes the rapid transmission and preliminary processing of data, but also ensures the accurate conversion of signals 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 spectrum information for subsequent in-depth analysis. Step S200 improves the overall efficiency and reliability of the system, and lays a solid foundation for accurate harmonic detection of low-voltage distribution network circuit breakers.

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

[0081] First, the number of transformation points is determined. In the actual spectrum analysis process, different types of waveforms are often most suitable for different numbers of transformation points. Generally speaking, when using the y-spectral 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, and x is 5, so the five-point transformation formula is used;

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

[0085]

[0086] Among them, k is the sampling point sequence, β is equivalent to gain, and γ is the attenuation coefficient;

[0087] It can be seen that the attenuation rate of the spectrum 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 the spectrum lines far away from the actual frequency point will be suppressed, thereby reducing the spectrum leakage component;

[0088] At the same time, the parameters of the two spectral lines n=k and n=k+1 can also be used to more accurately calculate the frequency, amplitude and phase of the actual harmonics. The specific method is as follows:

[0089]

[0090] Where m is the ratio of two adjacent spectral lines, α is a parameter in the frequency domain expression, 0<α<1;

[0091]

[0092] Among them, A i is the amplitude of the harmonic, θ i is the phase angle of the harmonic, represents the phase angle of x.

[0093] It should be noted that the above step S300 can not only effectively solve the errors caused by spectrum leakage and fence effect, but also accurately restore the harmonic components of the original signal, ensure the high accuracy of the harmonic detection results, provide reliable data support for the harmonic analysis of low-voltage distribution network circuit breakers, and enhance the system's ability to diagnose power quality problems, thereby helping to achieve more accurate and efficient power quality management.

[0094] In the embodiments of the present application, Figure 5 As shown in the above step S400, the harmonic amplitude and phase data are transmitted to the serial software through serial communication for analysis, so as to realize the harmonic detection of the low-voltage distribution network circuit breaker, realize the automation and real-time of the harmonic detection of the low-voltage distribution network circuit breaker, and the stability and efficiency of the serial communication ensure the accuracy of data transmission, so that the harmonic analysis can be completed quickly in the dedicated software, thereby providing a detailed power quality assessment in time, which not only simplifies the data analysis process, but also provides intuitive and reliable decision support for the operation and maintenance personnel, which helps to quickly respond to abnormal conditions 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 modification design method of this embodiment. It should be noted that the technical scheme of the low-voltage distribution network circuit breaker circuit modification design system and the technical scheme of the low-voltage distribution network circuit breaker circuit modification design method described above belong to the same concept, and the details of the technical scheme of the low-voltage distribution network circuit breaker circuit modification design system not described in detail in this embodiment can all be referred to the description of the technical scheme of the low-voltage distribution network circuit breaker circuit modification design method described above.

[0096] This embodiment also provides a low-voltage distribution network circuit breaker circuit modification design system, including:

[0097] A signal conversion module, used for converting the voltage and current signals input into the voltage and current conditioning circuit into signals that can be collected by the first chip;

[0098] A first processing module is used for the first chip to transmit the collected data to the second chip, and the second chip processes the data to obtain a spectrum diagram;

[0099] The second processing module is used to transform and reconstruct the spectrum sequence of adjacent points in the spectrum diagram using a multi-point transformation algorithm, and to correct the position of the spectrum line using a spectrum line interpolation method to obtain harmonic amplitude and phase data;

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

[0101] The above-mentioned unit modules may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above-mentioned modules.

[0102] This embodiment also provides an electronic device, which includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, an operator network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for designing a circuit modification of a low-voltage distribution network circuit breaker is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the housing of the computer device, or an external keyboard, touchpad or mouse, etc.

[0103] This embodiment also provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the method proposed in the above embodiment is implemented.

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

[0105] Through the above description of the implementation mode, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course it can also be implemented by hardware, but in many cases the former is a better implementation mode. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ReadOnly, Memory, ROM), random access memory (RandomAccess Memory, RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform the method of the embodiment of the present invention.

[0106] 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 preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0107] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the application can adopt 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.) that contain computer-usable program code. The scheme 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 of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes 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 generate 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.

[0109] 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 including 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.

[0110] 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.

[0111] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0112] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for designing circuit reconstruction of a low voltage distribution network circuit breaker, characterized in that: include: Inputting the voltage and current signals into the voltage and current conditioning circuit to convert them into signals 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 spectrum diagram; The spectrum sequence of adjacent points in the spectrum diagram is transformed and reconstructed using a multi-point transformation algorithm, and the position of the spectrum line is corrected using a spectrum line interpolation method to obtain harmonic amplitude and phase data; The harmonic amplitude and phase data are transmitted to the serial port software through serial port communication for analysis, thereby realizing harmonic detection of the low-voltage distribution network circuit breaker.

2. The low voltage distribution network circuit breaker circuit modification design method according to claim 1, characterized in that: The second chip processes the data to obtain a spectrum diagram including: Add a Hanning window to the collected signal; Input the windowed signal into the FFTIP core to obtain frequency domain data in complex form; The frequency domain data is modulo-modulated by a CORDICIP core to obtain an actual spectrum diagram.

3. The low voltage distribution network circuit breaker circuit modification design method according to claim 2, characterized in that: The time domain expression of the Hanning window is: Among them, ω(n) is the window function, N is the sampling length, R N (n) is the time domain expression of the rectangular window; The process of adding the Hanning window can be regarded as time domain multiplication, and the signal after the windowing is: x w (n)=x(n)·ω(n) Where x(n) is the signal before windowing; The Fourier transform of the windowed signal is: Among them, A0 is the amplitude of the signal, W(ω) is the spectrum function of the Hanning window, e -j2πnf is the exponential term of 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.

4. The low voltage distribution network circuit breaker circuit modification design method according to claim 3, characterized in that: The method of transforming and reconstructing the spectrum sequence of adjacent points in the spectrum diagram by using a multi-point transformation algorithm, and correcting the position of the spectrum line by using a spectrum line interpolation method to obtain harmonic amplitude and phase data includes: When using the y-spectral line interpolation method, the optimal number of transformation points x should satisfy: Where, l is the spectral line spacing; By determining the optimal number of transformation points, a five-point transformation is used to obtain the attenuation rate of the spectrum distribution. At the same time, the parameters of the two spectrum lines n=k and n=k+1 are used to calculate the frequency, amplitude and phase of the actual harmonics.

5. The low voltage distribution network circuit breaker circuit modification design method according to claim 1, characterized in that: The step of inputting the voltage and current signal into the voltage and current conditioning circuit to convert the signal that can be collected by the first chip comprises: The transformer ratio of the voltage conditioning circuit is 1:

1. A large resistor is used at the front end of the voltage conditioning circuit to convert the AC voltage source into a small AC current of mA level, and the small AC current of mA level is converted into a voltage range that can be sampled by ADC through an operational amplifier. The transformation ratio of the current conditioning circuit transformer is 1:1000, which converts the A-level large current of the harmonic source into mA-level small current, and then converts the mA-level small current into a voltage range that can be sampled by ADC through a bias circuit and an operational amplifier.

6. The method for designing circuit reconstruction of a circuit breaker in a low-voltage distribution network according to claim 5, characterized in that: The power supply circuit uses a voltage regulator tube and an electrolytic capacitor to stabilize the voltage at a fixed value, which is used to bias the voltage and current conditioning circuit.

7. The method for designing circuit reconstruction of a circuit breaker in a low voltage distribution network according to claim 6, characterized in that: The first chip transmitting the collected data to the second chip comprises: Confirming that the specification of the first chip meets the transmission standard; Decide whether to use SPI serial communication or parallel output mode based on application requirements and transmission speed requirements; After confirming the transmission mode, the first chip transmits the collected data to the second chip.

8. A system using the low-voltage distribution network circuit breaker circuit reconstruction design method according to any one of claims 1 to 7, characterized in that: include: A signal conversion module, used for converting the voltage and current signals input into the voltage and current conditioning circuit into signals that can be collected by the first chip; A first processing module, configured for the first chip to transmit the collected data to the second chip, and the second chip to process the data to obtain a spectrum diagram; The second processing module is used to transform and reconstruct the spectrum sequence of adjacent points in the spectrum diagram using a multi-point transformation algorithm, and to correct the position of the spectrum line using a spectrum line interpolation method to obtain harmonic amplitude and phase data; The monitoring and analysis module is used to transmit the harmonic amplitude and phase data to the serial port software through serial port communication for analysis, so as to realize harmonic detection of the low-voltage distribution network circuit breaker.

9. An electronic device, comprising: Memory and processor; The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the low-voltage distribution network circuit breaker circuit modification design method described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the low-voltage distribution network circuit breaker circuit reconstruction design method according to any one of claims 1 to 7.

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