Device for simulating generation and time measurement of harmonic waves in power supply grid

Abstract

The utility model discloses a device for simulating generation and time measurement of harmonic waves in a power supply grid, and the device comprises an MCU module, a waveform processing output module, a waveform recovery processing module, a contact input module, and a display operation module. The MCU module comprises a central control unit, a waveform generation unit, a DA conversion unit, an AD conversion unit, a timing unit and a display operation communication unit, the waveform generation unit and the DA conversion unit are connected with the central control unit, and the output end of the DA conversion unit is connected with the input end of the waveform processing output module. And the output end of the waveform processing output module is used for providing final harmonic current or harmonic voltage, and different required harmonic waves in a simulation power supply grid are generated through the waveform generation unit and the waveform synthesis unit, so that the tripping time of the circuit breaker with various input harmonic waves is detected.

Description

Technical Field

[0001] This utility model relates to the field of trip detection, and in particular to a device for simulating the generation and timing of harmonics in a power grid. Background Technology

[0002] Power systems contain various nonlinear components, such as AC generators, transformers, and capacitors. These components can become sources of harmonics in the power grid during operation. These devices and loads exhibit nonlinear characteristics, meaning the applied voltage and generated current are not linearly related, causing distortion of the power system's sinusoidal waveform and the emergence of higher-order harmonics, i.e., harmonic currents and voltages. The presence or absence of harmonics will result in different tripping times for circuit breakers during current protection, which needs to be detected. Therefore, it is necessary to detect the tripping time of circuit breakers. Currently, detecting the impact of harmonics on the tripping time of circuit breakers requires supplying the circuit breaker with an actual large current harmonic, which is expensive, time-consuming, and inconvenient for the development of electronic protection products. Utility Model Content

[0003] The technical problem solved by this utility model is to provide a device for simulating the generation and timing of harmonics in a power grid, which can detect the tripping time of circuit breaker current protection under different set harmonic ratios.

[0004] The technical solution adopted by this utility model to solve its technical problem is: a device for generating and timing harmonics in a simulated power grid, including an MCU module, a waveform processing output module, a waveform retrieval processing module, a contact input module, and a display operation module. The MCU module includes a central control unit, a waveform generation unit, a DA conversion unit, an AD conversion unit, a timing unit, and a display operation communication unit. The waveform generation unit, the DA conversion unit, and the central control unit are connected. The output terminal of the DA conversion unit is connected to the input terminal of the waveform processing output module. The output terminal of the waveform processing output module is used to provide the final harmonic current or harmonic voltage.

[0005] The central control unit is used to connect to the contact input module;

[0006] The central control unit is used to control the start and stop of the timing unit to obtain the tripping time of the external trip unit;

[0007] The waveform generation unit is used to generate the fundamental wave, the 3rd harmonic, the 5th harmonic, the 7th harmonic, and the 21st harmonic.

[0008] The waveform synthesis unit is used to superimpose and synthesize the generated fundamental wave, 3rd harmonic, 5th harmonic, 7th harmonic and 21st harmonic;

[0009] The DA conversion unit is used to convert analog waveforms into digital waveforms.

[0010] The waveform processing output module is used to amplify or convert the voltage waveform output by the DA into current.

[0011] The AD conversion unit is used to measure the waveform of the final harmonic current or voltage output after processing by the waveform retrieval module.

[0012] The timing unit is used to time the contact input module.

[0013] Furthermore, the MCU module also includes an AD conversion unit, the input of which is connected to the output of the waveform back sampling processing module, and the input of which is connected to the central control unit.

[0014] Furthermore, it also includes a display operation module, which is connected to the MCU module.

[0015] Furthermore, the display operation module includes a display unit and a control unit;

[0016] The display unit is used to display the tripping time of the trip unit and the waveform parameters of the output synthesized harmonics;

[0017] The control unit is used to set the synthesis ratio of each waveform for the waveform generation unit.

[0018] Furthermore, the MCU module is a single-chip microcomputer.

[0019] The beneficial effects of this utility model are:

[0020] 1. In this structure, different harmonics in the simulated power grid are generated through the waveform generation unit and the waveform synthesis unit, thereby realizing the detection of the circuit breaker tripping time of various input harmonics.

[0021] 2. The MCU module also includes an AD conversion unit. The input terminal of the AD conversion unit is connected to the output terminal of the signal processing module, thereby enabling the detection of output harmonics and ensuring the accuracy of the output harmonics. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a device for generating harmonics in a simulated power grid according to an embodiment of this application.

[0023] Figure 2 This is a schematic diagram of the MCU module of the device for generating harmonics in a simulated power grid according to an embodiment of this application.

[0024] Figure 3This is a schematic diagram of the waveform generated by the waveform generation unit and the waveform synthesis unit in the apparatus for generating harmonics in a simulated power grid according to an embodiment of this application. Detailed Implementation

[0025] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0026] like Figure 1 and Figure 2 As shown, this application discloses a device for generating and timing harmonics in a simulated power grid, including an MCU module, a waveform processing output module, a waveform retrieval processing module, a contact input module, and a display and operation module. The MCU module includes a central control unit, a waveform generation unit, a DA conversion unit, an AD conversion unit, a timing unit, and a display, operation, and communication unit. The waveform generation unit, DA conversion unit, and central control unit are connected. The output terminal of the DA conversion unit is connected to the input terminal of the waveform processing output module, and the output terminal of the waveform processing output module is used to provide the final harmonic current or harmonic voltage.

[0027] The central control unit is used to connect to the contact input module;

[0028] The central control unit is used to control the start and stop of the timing unit and obtain the time when the external trip unit trips and causes the state of the contact input module to flip.

[0029] The waveform processing output module is used to filter, amplify, and convert voltage into current in the waveform output from the DA converter.

[0030] The waveform processing output module processes the analog voltage waveform output by the DA converter, converting it into either a voltage waveform or a current waveform for output, without limitation on the amplitude of the output current or voltage.

[0031] The waveform generation unit is used to superimpose the generated fundamental wave, 3rd harmonic, 5th harmonic, 7th harmonic and 21st harmonic and synthesize them into multiple harmonic data according to a set ratio.

[0032] The DA conversion unit is used to convert the waveform data of multiple harmonics generated by the waveform generation unit into analog waveforms and output them to the waveform processing output module.

[0033] The timing unit is used for timing.

[0034] Specifically, the MCU module is a single-chip microcomputer.

[0035] In practice, the waveform generation unit generates the fundamental wave, the 3rd harmonic, the 5th harmonic, the 7th harmonic, and the 21st harmonic, forming n value points within one cycle (e.g., 100 value points). Then, according to the set synthesis ratio of each waveform, the waveform synthesis unit superimposes and synthesizes the fundamental wave, the 3rd harmonic, the 5th harmonic, the 7th harmonic, and the 21st harmonic. After synthesis, the waveform is sequentially converted into an analog waveform by the DA conversion unit at a frequency of 100*50Hz or 100*60Hz and sent to the waveform processing output module. The output waveform can be either a voltage output or a current output. Finally, it is output to the circuit breaker's control equipment. When the output signal is received, the central control unit controls the timing unit to start timing. When the central control unit receives the trip signal from the trip unit and detects the contact input module state flipping, the central control unit controls the timing unit to stop timing, thus obtaining the entire trip time.

[0036] Specifically, when 100 value points are taken in a waveform, the fundamental waveform mentioned above is as follows:

[0037] The waveform of the third harmonic is: The waveform of the 5th harmonic is as follows: The waveform of the 7th harmonic is as follows:

[0038] The waveform of the 21st harmonic is as follows: The synthesized harmonics are:

[0039]

[0040] Where n is 1-100, K3, K5, K7, and K21 are the ratio coefficients of each harmonic relative to the fundamental wave, and each ratio coefficient can be set according to the detection requirements.

[0041] In this structure, different harmonics in the simulated power grid are generated through a waveform generation unit and a waveform synthesis unit, thereby enabling the detection of the circuit breaker tripping time for various output harmonics.

[0042] In this embodiment, the MCU module further includes an AD conversion unit. The input terminal of the AD conversion unit is connected to the waveform back sampling processing module. The waveform back sampling processing module is connected to an external harmonic current or voltage. After sampling by the AD conversion unit, the waveform back sampling processing module converts the data to obtain harmonic waveform data. Based on the harmonic data, Fourier transform is performed to calculate the harmonic waveforms.

[0043] Specifically, after the synthesized harmonic signal is output, the output signal is returned to the central control unit for monitoring by the inverse conversion of the AD conversion unit.

[0044] The above connection structure can detect the output signal. If the output signal is different from the preset output signal, the accuracy of the output signal can be ensured by readjusting the ratio of each harmonic.

[0045] The above connection structure is configured to obtain 100 harmonic output values ​​through AD conversion. The MCU module then uses Fourier transform to calculate the effective value, peak value, and percentage of the effective value relative to the fundamental wave, the 3rd harmonic, the 5th harmonic, the 7th harmonic, and the 21st harmonic.

[0046] In this embodiment, a display operation module is also included, which is connected to the MCU module.

[0047] The display operation module includes a display unit and a control unit;

[0048] The display unit displays the tripping time and the output waveform of the trip unit;

[0049] The control unit is used to send the synthesis ratio requirements of each waveform to the waveform synthesis unit.

[0050] Specifically, the circuit breaker tripping time and its corresponding synthesized harmonics detected in the MCU module can be displayed in the display unit. When it is necessary to change the synthesis ratio of each synthesized harmonic, the ratio of each harmonic can be manually modified through the control unit, and the control signal is transmitted to the MCU module. The waveform synthesis unit in the MCU module will synthesize the harmonics according to the modified harmonic ratio.

[0051] In this structure, the display operation module allows for convenient observation of harmonic waveforms and their corresponding tripping times, and also facilitates easy modification of the proportion of each harmonic.

[0052] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above descriptions are merely specific embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A device for simulating the generation and timing of harmonics in a power grid, characterized in that: It includes an MCU module, a waveform processing output module, a waveform retrieval processing module, a contact input module, and a display operation module. The MCU module includes a central control unit, a waveform generation unit, a DA conversion unit, an AD conversion unit, a timing unit, and a display operation communication unit. The waveform generation unit, DA conversion unit, and central control unit are connected. The output terminal of the DA conversion unit is connected to the input terminal of the waveform processing output module. The output terminal of the waveform processing output module is used to provide the final harmonic current or harmonic voltage. The central control unit is used to connect to the contact input module; The central control unit is used to control the start and stop of the timing unit to obtain the tripping time of the external trip unit; The waveform generation unit is used to superimpose and synthesize the generated fundamental wave, 3rd harmonic, 5th harmonic, 7th harmonic and 21st harmonic; The DA conversion unit is used to convert digital waveform values ​​into analog voltage waveforms. The waveform processing output module is used to amplify or convert the voltage waveform output by the DA into current. The AD conversion unit is used to measure the waveform of the final harmonic current or voltage output after processing by the waveform retrieval module. The timing unit is used to time the contact input module.

2. The device for generating and timing harmonics in a simulated power grid as described in claim 1, characterized in that: The MCU module also includes an AD conversion unit, the input of which is connected to the output of the waveform back sampling processing module, and the input of which is connected to the central control unit.

3. The device for generating and timing harmonics in a simulated power grid as described in claim 1, characterized in that: It also includes a display operation module, which is connected to the MCU module.

4. The device for generating and timing harmonics in a simulated power grid as described in claim 3, characterized in that: The display operation module includes a display unit and a control unit; The display unit is used to display the tripping time of the trip unit and the waveform parameters of the output synthesized harmonics; The control unit is used to set the synthesis ratio of each waveform for the waveform generation unit.

5. The device for generating and timing harmonics in a simulated power grid as described in claim 1, characterized in that: The MCU module is a single-chip microcomputer.

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