A multi-voltage division ratio low frequency voltage proportion measurement system and method
By using a multi-voltage-ratio low-frequency voltage proportional measurement system, employing the principle of an active capacitor voltage divider and automatic voltage ratio switching technology, the accuracy problem of low-frequency transformers and voltage dividers in the low-frequency range is solved, enabling precise measurement of low-frequency voltages from 10kV to 220kV, reducing the influence of dielectric loss, and improving measurement accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA ELECTRIC POWER RESEARCH INSTITUTE CO LTD
- Filing Date
- 2026-03-09
- Publication Date
- 2026-06-12
AI Technical Summary
Existing low-frequency transformers and voltage dividers suffer from problems such as core saturation, increased iron and copper losses, and decreased accuracy in the low-frequency range. Furthermore, voltage dividers of different voltage levels have a single voltage division ratio, which cannot match the impedance of the high-voltage side and the low-voltage side, resulting in insufficient accuracy of low-frequency voltage ratio measurement.
A multi-voltage-ratio low-frequency voltage proportional measurement system is adopted, which includes a two-stage capacitor voltage divider structure, a low-voltage capacitor series-parallel combination network, an automatic voltage division ratio switching module, an active impedance matching voltage follower, and a voltage compensation unit. Through the principle of active capacitor voltage divider and automatic voltage division ratio switching technology, it realizes precise measurement of low-frequency voltage under multiple voltage division ratios.
It enables precise measurement of low-frequency voltage under different voltage division ratios, reduces the influence of low-voltage arm dielectric loss, improves measurement accuracy, meets the measurement requirements of 10kV-220kV low-frequency voltage, and has an error better than 1×10-4.
Smart Images
Figure CN122193676A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of precision voltage measurement technology, and more specifically, to a multi-voltage-ratio low-frequency voltage proportional measurement system and method. Background Technology
[0002] As the energy transition towards low-carbon goals continues to deepen, the primary task of new power systems will be to maximize the utilization of new energy sources. Low-frequency transmission (15Hz-30Hz) projects combine the advantages of large-capacity power transmission with the economic efficiency of initial investment, making them suitable for typical medium- and long-distance scenarios such as offshore wind power transmission, island power grid interconnection, and urban power grids. Low-frequency transmission technology selects the 15Hz-30Hz frequency range to reduce line impedance and, through the potential exploitation of the frequency dimension, enhances the system's power transmission capacity and flexible control capabilities. As a key metering / measurement device in low-frequency power transmission projects, the existing instrument transformer development technology has limited applicability in the low-frequency field: traditional 50Hz power frequency electromagnetic instrument transformers will experience deep core saturation when operating near low frequencies (15Hz~30Hz), requiring an increase in the core cross-sectional area, which leads to a significant increase in iron and copper losses, and a sharp drop in instrument transformer accuracy. Anti-saturation and high accuracy at low frequencies are mutually restrictive, making it difficult to improve accuracy; in the traditional voltage divider structure, the low-voltage side capacitor is affected by the back-end electronic circuit, DC signal path and dielectric loss, resulting in reduced accuracy. The voltage division ratio of voltage dividers for different voltage levels is singular, and the low-voltage side impedance cannot keep up with the high-voltage side impedance changes. Summary of the Invention
[0003] This invention proposes a multi-voltage-ratio low-frequency voltage proportional measurement system and method to solve the problem of precise measurement of low-frequency voltage ratios under different voltage ratios.
[0004] To address the aforementioned problems, according to one aspect of the present invention, a multi-voltage-ratio low-frequency voltage proportional measurement system is provided, the system comprising: a two-stage capacitor voltage divider structure, a low-voltage capacitor series-parallel combination network, an automatic voltage divider ratio switching module, an active impedance matching voltage follower, and a voltage compensation unit. The two-stage capacitor voltage divider structure includes a high-voltage side capacitor and a low-voltage side capacitor; the first terminal of the high-voltage side capacitor is connected to the high-voltage side input low-frequency voltage Ui, and the low-voltage side capacitor is connected to the input terminal of the active impedance matching voltage follower; The output terminal of the active impedance matching voltage follower is connected to the input terminal of the low-voltage capacitor series-parallel combination network and the input terminal of the voltage compensation unit, respectively. The low-voltage capacitor series-parallel combination network includes multiple solid capacitors with different capacitance values, including those connected in series and parallel. The control terminal of the low-voltage capacitor series-parallel combination network is connected to the automatic voltage division ratio switching module. The automatic voltage division ratio switching module changes the total capacitance value on the low-voltage side to achieve multiple voltage division ratio switching. The voltage compensation unit outputs a corresponding compensation voltage ΔU according to the switched voltage division ratio, and superimposes the compensation voltage ΔU onto the output of the system to obtain the calibrated low-voltage side low-frequency voltage Uo.
[0005] Preferably, the value of the high-voltage side capacitor is set to a fixed value according to the rated voltage level of the power system corresponding to the low-frequency voltage Ui input to the high-voltage side being measured; wherein, the high-voltage side capacitor corresponding to the rated voltage level of the 10kV power system is 200pF, the high-voltage side capacitor corresponding to the rated voltage level of the 110kV power system is 100pF, and the high-voltage side capacitor corresponding to the rated voltage level of the 220kV power system is 50pF.
[0006] Preferably, the fixed capacitors in the low-voltage capacitor series-parallel combination network include 50nF, 100nF, 200nF and 500nF specifications; the series and parallel connection mode of the fixed capacitors is controlled by the logic controller in the voltage division ratio automatic switching module to realize multiple voltage division ratio outputs.
[0007] Preferably, the active impedance matching voltage follower includes two operational amplifiers UA and UB with identical parameters, as well as resistors R1, R2, and capacitor C0. The positive input terminal of the operational amplifier UA is connected to the input voltage Uix of the active impedance matching voltage follower, and the output terminal of the operational amplifier UA is connected to the output voltage Uox of the active impedance matching voltage follower, and is connected to the series resistors R1 and R2. The negative input terminal of the operational amplifier UA is connected to the negative input terminal of the operational amplifier UB via resistors R1 and R2, and the positive input terminal of the operational amplifier UB is connected to the output voltage Uox of the active impedance matching voltage follower. The active impedance-matched voltage follower achieves low-deviation voltage following and electrical isolation output between the preceding and following stages.
[0008] Preferably, the output voltage Uox of the active impedance matching voltage follower and the voltage division ratio signal output by the automatic voltage division ratio switching module are processed and input to the voltage compensation unit. The voltage compensation unit outputs a compensation voltage ΔU and superimposes it onto the output of the system to obtain the calibrated low-voltage side low-frequency voltage Uo.
[0009] Based on another aspect of the present invention, the present invention provides a method for measuring the low-frequency voltage ratio of multiple voltage dividers. The method includes establishing a measurement system, which includes: a two-stage capacitor voltage divider structure, a low-voltage capacitor series-parallel combination network, an automatic voltage divider ratio switching module, an active impedance matching voltage follower, and a voltage compensation unit. The two-stage capacitor voltage divider structure includes a high-voltage side capacitor and a low-voltage side capacitor; the first terminal of the high-voltage side capacitor is connected to the high-voltage side input low-frequency voltage Ui, and the low-voltage side capacitor is connected to the input terminal of the active impedance matching voltage follower; The output terminal of the active impedance matching voltage follower is connected to the input terminal of the low-voltage capacitor series-parallel combination network and the input terminal of the voltage compensation unit, respectively. The low-voltage capacitor series-parallel combination network includes multiple solid capacitors with different capacitance values, including those connected in series and parallel. The control terminal of the low-voltage capacitor series-parallel combination network is connected to the automatic voltage division ratio switching module. The automatic voltage division ratio switching module changes the total capacitance value on the low-voltage side to achieve multiple voltage division ratio switching. The voltage compensation unit outputs a corresponding compensation voltage ΔU based on the switched voltage division ratio, and the compensation voltage ΔU is superimposed on the output of the system to obtain the calibrated low-voltage side low-frequency voltage Uo.
[0010] Preferably, the value of the high-voltage side capacitor is set to a fixed value according to the rated voltage level of the power system corresponding to the low-frequency voltage Ui input to the high-voltage side being measured; wherein, the high-voltage side capacitor corresponding to the rated voltage level of the 10kV power system is 200pF, the high-voltage side capacitor corresponding to the rated voltage level of the 110kV power system is 100pF, and the high-voltage side capacitor corresponding to the rated voltage level of the 220kV power system is 50pF.
[0011] Preferably, the fixed capacitors in the low-voltage capacitor series-parallel combination network are configured with specifications including 50nF, 100nF, 200nF and 500nF; the series-parallel connection mode of the fixed capacitors is controlled by the logic controller in the voltage division ratio automatic switching module to achieve multiple voltage division ratio outputs.
[0012] Preferably, the active impedance matching voltage follower includes two operational amplifiers UA and UB with identical parameters, as well as resistors R1, R2, and capacitor C0. Connect the positive input terminal of the operational amplifier UA to the input voltage Uix of the active impedance matching voltage follower, connect the output terminal of the operational amplifier UA to the output voltage Uox of the active impedance matching voltage follower, and connect it to the series resistors R1 and R2. Connect the negative input terminal of the operational amplifier UA to the negative input terminal of the operational amplifier UB via resistors R1 and R2, and connect the positive input terminal of the operational amplifier UB to the output voltage Uox of the active impedance matching voltage follower. The active impedance-matched voltage follower enables low-deviation voltage following and electrical isolation output between the preceding and following stages.
[0013] Preferably, the output voltage Uox of the active impedance matching voltage follower and the voltage division ratio signal output by the automatic voltage division ratio switching module are processed and input into the voltage compensation unit. The voltage compensation unit outputs a compensation voltage ΔU and superimposes it onto the output terminal of the system to obtain the calibrated low-voltage side low-frequency voltage Uo.
[0014] This invention provides a multi-voltage-ratio low-frequency voltage proportional measurement system and method. The system includes: a two-stage capacitive voltage divider structure, a low-voltage capacitor series-parallel combination network, an automatic voltage division ratio switching module, an active impedance matching voltage follower, and a voltage compensation unit. The two-stage capacitive voltage divider structure includes a high-voltage side capacitor and a low-voltage side capacitor. The first terminal of the high-voltage side capacitor is connected to the high-voltage side input low-frequency voltage Ui, and the low-voltage side capacitor is connected to the input terminal of the active impedance matching voltage follower. The output terminal of the active impedance matching voltage follower is connected to the input terminal of the low-voltage capacitor series-parallel combination network and the input terminal of the voltage compensation unit. The low-voltage capacitor series-parallel combination network includes multiple solid capacitors with different capacitance values, including series and parallel connections. The control terminal of the low-voltage capacitor series-parallel combination network is connected to the automatic voltage division ratio switching module. The automatic voltage division ratio switching module changes the total capacitance value of the low-voltage side to achieve multi-voltage-ratio switching. The voltage compensation unit outputs a corresponding compensation voltage ΔU according to the switched voltage division ratio and superimposes the compensation voltage ΔU onto the output terminal of the system to obtain the calibrated low-voltage side low-frequency voltage Uo. The technical solution of this invention proposes a low-frequency voltage ratio measurement system and method with multiple voltage divider ratios. It adopts the principle of active capacitor voltage divider, designs a combination structure of various low-voltage capacitor series and parallel connection methods to reduce the influence of low-voltage arm dielectric loss, and adopts automatic voltage divider ratio switching and active impedance matching technology to meet the needs of precise measurement of low-frequency voltage ratios under different voltage divider ratios. Attached Figure Description
[0015] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures: Figure 1 This is a structural diagram of a multi-voltage ratio low-frequency voltage proportional measurement system according to an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the low-frequency voltage proportional measurement principle according to an embodiment of the present invention; Figure 3This is a flowchart of a low-frequency voltage ratio measurement method with multiple voltage divider ratios according to an embodiment of the present invention. Detailed Implementation
[0016] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.
[0017] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.
[0018] Figure 1 This is a structural diagram of a multi-voltage ratio low-frequency voltage proportional measurement system according to an embodiment of the present invention.
[0019] This invention proposes a low-frequency voltage ratio measurement system with multiple voltage divider ratios. It adopts the principle of an active capacitor voltage divider and designs a combination structure of various low-voltage capacitor series and parallel connections to reduce the influence of low-voltage arm dielectric loss. It also employs automatic voltage divider ratio switching and active impedance matching technology to meet the needs of precise measurement of low-frequency voltage ratios under different voltage divider ratios.
[0020] like Figure 1 As shown, the present invention provides a multi-voltage ratio low-frequency voltage proportional measurement system, the system comprising: a two-stage capacitor voltage divider structure 101, a low-voltage capacitor series-parallel combination network 102, an automatic voltage division ratio switching module 103, an active impedance matching voltage follower 104, and a voltage compensation unit 105. This invention provides a low-frequency voltage proportional measurement system with switching voltage division ratios. To improve the measurement accuracy of 10kV-220kV low-frequency voltages, it employs the principle of an active capacitive voltage divider and designs various series-parallel combinations of low-voltage capacitors to reduce the influence of low-voltage arm dielectric losses. It also utilizes automatic voltage division ratio switching and active impedance matching technology to ensure that the low-frequency voltage proportional error is better than 1×10⁻⁶ under different voltage division ratios. -4 .
[0021] The two-stage capacitor voltage divider structure 101 includes a high-voltage side capacitor and a low-voltage side capacitor; the first terminal of the high-voltage side capacitor is connected to the high-voltage side input low-frequency voltage Ui, and the low-voltage side capacitor is connected to the input terminal of the active impedance matching voltage follower 104. The output of the active impedance matching voltage follower 104 is connected to the input of the low-voltage capacitor series-parallel combination network 102 and the input of the voltage compensation unit 105, respectively. The low-voltage capacitor series-parallel combination network 102 includes multiple solid capacitors with different capacitance values, including series and parallel connections. The control terminal of the low-voltage capacitor series-parallel combination network 102 is connected to the voltage division ratio automatic switching module 103. The total capacitance value on the low-voltage side is changed through the voltage division ratio automatic switching module 103 to achieve multiple voltage division ratio switching. The voltage compensation unit 105 outputs a corresponding compensation voltage ΔU according to the switched voltage division ratio, and superimposes the compensation voltage ΔU onto the output of the system to obtain the calibrated low-frequency voltage Uo on the low-voltage side.
[0022] Preferably, the value of the high-voltage side capacitor is set to a fixed value according to the rated voltage level of the power system corresponding to the low-frequency input voltage Ui of the measured high-voltage side; wherein, the high-voltage side capacitor corresponding to the rated voltage level of the 10kV power system is 200pF, the high-voltage side capacitor corresponding to the rated voltage level of the 110kV power system is 100pF, and the high-voltage side capacitor corresponding to the rated voltage level of the 220kV power system is 50pF.
[0023] In this invention, U i For high-voltage side input low-frequency voltage, U o The low-frequency voltage output on the low-voltage side is composed of a two-stage capacitor voltage divider. The high-voltage side capacitor has a fixed value, designed according to the voltage level. The design value of the 10kV high-voltage side capacitor is 200pF, the 110kV high-voltage side capacitor is 100pF, and the 220kV high-voltage side capacitor is 50pF.
[0024] Preferably, the fixed capacitors in the low-voltage capacitor series-parallel combination network 102 include specifications of 50nF, 100nF, 200nF and 500nF; the series and parallel connection mode of the fixed capacitors is controlled by the logic controller in the voltage division ratio automatic switching module to realize multiple voltage division ratio outputs.
[0025] The low-voltage side capacitor of this invention is formed by a series-parallel structure network, which mainly consists of solid capacitors of different specifications, such as 50nF, 100nF, 200nF and 500nF, combined according to the series-parallel structure. Various capacitor voltage division ratios can be achieved by a logic controller to ensure that the output low-frequency voltage matches the subsequent measurement equipment.
[0026] Preferably, the active impedance matching voltage follower 104 includes two operational amplifiers UA and UB with identical parameters, as well as resistors R1, R2, and capacitor C0. The positive input terminal of the operational amplifier UA is connected to the input voltage Uix of the active impedance matching voltage follower, and the output terminal of the operational amplifier UA is connected to the output voltage Uox of the active impedance matching voltage follower, and is connected in series with resistors R1 and R2. The negative input terminal of operational amplifier UA is connected to the negative input terminal of operational amplifier UB via resistors R1 and R2. The positive input terminal of operational amplifier UB is connected to the output voltage Uox of an active impedance matching voltage follower. The active impedance-matched voltage follower 104 achieves low-deviation voltage following and electrical isolation output between the preceding and following stages.
[0027] Preferably, the output voltage Uox of the active impedance matching voltage follower 104 and the voltage division ratio signal output by the voltage division ratio automatic switching module are processed and input to the voltage compensation unit 105. The voltage compensation unit 105 outputs a compensation voltage ΔU and superimposes it on the output of the system to obtain the calibrated low-voltage side low-frequency voltage Uo.
[0028] Figure 2 This is a schematic diagram illustrating the principle of low-frequency voltage proportional measurement according to an embodiment of the present invention.
[0029] like Figure 2 As shown, a voltage follower is connected between the high-voltage and low-voltage sides. The voltage follower consists of two operational amplifiers with identical parameters and resistors R1, R2, and capacitor C0. The positive input terminal of operational amplifier UB is connected to the output voltage Uox of the voltage follower. Then, the negative input terminal of operational amplifier UA is connected to resistors R1 and R2 in series, and then connected to the negative input terminal of operational amplifier UB. Furthermore, the output terminal of operational amplifier UA is connected to resistors R1 and R2, and its output is connected to the output voltage Uox of the voltage follower. The positive input terminal of operational amplifier UA is connected to the input voltage Uix of the voltage follower. This follower circuit achieves low-deviation voltage following characteristics and ensures isolated outputs.
[0030] In this invention, the voltage follower output voltage Uox is calculated with the feedback parameters and then processed by the voltage control unit to obtain ΔU, which is then compensated to the output terminal of the device to obtain the output voltage Uo.
[0031] This invention adopts the principle of an active capacitor voltage divider and designs a combination structure of various low-voltage capacitor series and parallel connections to reduce the influence of low-voltage arm dielectric loss. By using automatic voltage division ratio switching and active impedance matching technology, a single low-voltage arm device can be matched with high-voltage capacitors of different voltage levels, meeting the requirements for precise measurement of low-frequency voltage ratios under different voltage division ratios and ensuring the accuracy of 10kV-220kV low-frequency standard voltage ratio measurement.
[0032] like Figure 2 As shown, U i For high-voltage side input low-frequency voltage, U o The low-frequency voltage output on the low-voltage side is composed of a two-stage capacitor voltage divider. The high-voltage side capacitor has a fixed value, designed according to the voltage level. The design value of the 10kV high-voltage side capacitor is 200pF, the 110kV high-voltage side capacitor is 100pF, and the 220kV high-voltage side capacitor is 50pF.
[0033] like Figure 2 As shown, the low-voltage side capacitors are formed by a series-parallel network structure, which mainly consists of solid capacitors of different specifications, such as 50nF, 100nF, 200nF, and 500nF, combined according to the series-parallel structure. The logic controller can realize various capacitor voltage division ratios to ensure that the output low-frequency voltage matches the subsequent measurement equipment.
[0034] like Figure 2 As shown, a voltage follower is connected between the high-voltage and low-voltage sides. The voltage follower consists of two operational amplifiers with identical parameters and resistors R1, R2, and capacitor C0. The positive input terminal of operational amplifier UB is connected to the output voltage Uox of the voltage follower. Then, the negative input terminal of operational amplifier UA is connected to resistors R1 and R2 in series, and then connected to the negative input terminal of operational amplifier UB. Furthermore, the output terminal of operational amplifier UA is connected to resistors R1 and R2, and its output is connected to the output voltage Uox of the voltage follower. The positive input terminal of operational amplifier UA is connected to the input voltage Uix of the voltage follower. This follower circuit achieves low-deviation voltage following characteristics and ensures isolated outputs.
[0035] like Figure 2 As shown, the voltage follower output voltage Uox is calculated with the feedback parameters and then processed by the voltage control unit to obtain ΔU, which is then compensated to the output terminal of the device to obtain the output voltage Uo.
[0036] Figure 3 This is a flowchart of a low-frequency voltage ratio measurement method with multiple voltage divider ratios according to an embodiment of the present invention.
[0037] like Figure 3 As shown, the present invention provides a method for measuring the proportion of low-frequency voltage with multiple voltage divider ratios, the method comprising: Step 301: Establish a measurement system, which includes: a two-stage capacitor voltage divider structure, a low-voltage capacitor series-parallel combination network, an automatic voltage divider ratio switching module, an active impedance matching voltage follower, and a voltage compensation unit. Step 302: The two-stage capacitor voltage divider structure includes a high-voltage side capacitor and a low-voltage side capacitor; connect the first terminal of the high-voltage side capacitor to the high-voltage side input low-frequency voltage Ui, and connect the low-voltage side capacitor to the input terminal of the active impedance matching voltage follower; Step 303: Connect the output of the active impedance matching voltage follower to the input of the low-voltage capacitor series-parallel combination network and the input of the voltage compensation unit, respectively. Step 304: The low-voltage capacitor series-parallel combination network includes multiple solid capacitors with different capacitance values, including series and parallel ones. The control terminal of the low-voltage capacitor series-parallel combination network is connected to the automatic voltage division ratio switching module. The total capacitance value on the low-voltage side is changed through the automatic voltage division ratio switching module to realize multi-voltage division ratio switching. Step 305: The voltage compensation unit outputs the corresponding compensation voltage ΔU according to the switched voltage division ratio, and the compensation voltage ΔU is superimposed on the output of the system to obtain the calibrated low-voltage side low-frequency voltage Uo.
[0038] Preferably, the value of the high-voltage side capacitor is set to a fixed value according to the rated voltage level of the power system corresponding to the low-frequency input voltage Ui of the measured high-voltage side; wherein, the high-voltage side capacitor corresponding to the rated voltage level of the 10kV power system is 200pF, the high-voltage side capacitor corresponding to the rated voltage level of the 110kV power system is 100pF, and the high-voltage side capacitor corresponding to the rated voltage level of the 220kV power system is 50pF.
[0039] Preferably, the fixed capacitors in the low-voltage capacitor series-parallel combination network are configured with specifications including 50nF, 100nF, 200nF and 500nF; the series-parallel connection mode of the fixed capacitors is controlled by the logic controller in the voltage division ratio automatic switching module to achieve multiple voltage division ratio outputs.
[0040] Preferably, the active impedance-matched voltage follower includes two operational amplifiers UA and UB with identical parameters, as well as resistors R1, R2, and capacitor C0. Connect the positive input terminal of the operational amplifier UA to the input voltage Uix of the active impedance matching voltage follower, connect the output terminal of the operational amplifier UA to the output voltage Uox of the active impedance matching voltage follower, and connect it to the series resistors R1 and R2. Connect the negative input terminal of operational amplifier UA to the negative input terminal of operational amplifier UB via resistors R1 and R2, and connect the positive input terminal of operational amplifier UB to the output voltage Uox of the active impedance matching voltage follower. Low-deviation voltage following and electrical isolation between upstream and downstream stages are achieved through an active impedance-matched voltage follower.
[0041] Preferably, the output voltage Uox of the active impedance matching voltage follower and the voltage division ratio signal output by the voltage division ratio automatic switching module are processed and input into the voltage compensation unit. The voltage compensation unit outputs a compensation voltage ΔU and superimposes it onto the output of the system to obtain the calibrated low-frequency voltage Uo on the low-voltage side.
[0042] The multi-voltage ratio low-frequency voltage proportional measurement method of the present invention corresponds to the multi-voltage ratio low-frequency voltage proportional measurement system of the present invention, and will not be described again here.
[0043] The present invention has been described with reference to a few embodiments. However, it will be apparent to those skilled in the art that other embodiments besides those disclosed above fall equivalently within the scope of the present invention.
[0044] Generally, all terms used in this invention are interpreted according to their ordinary meaning in the art, unless otherwise expressly defined herein. All references to "a / / the [device, component, etc.]" are openly interpreted as at least one instance of a device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed, unless explicitly stated otherwise.
[0045] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.
[0046] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0047] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.
[0048] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.
[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the present invention.
Claims
1. A multi-voltage ratio low-frequency voltage proportional measurement system, characterized in that, The system includes: a two-stage capacitor voltage divider structure, a low-voltage capacitor series-parallel combination network, an automatic voltage divider ratio switching module, an active impedance matching voltage follower, and a voltage compensation unit. The two-stage capacitor voltage divider structure includes a high-voltage side capacitor and a low-voltage side capacitor; the first terminal of the high-voltage side capacitor is connected to the high-voltage side input low-frequency voltage Ui, and the low-voltage side capacitor is connected to the input terminal of the active impedance matching voltage follower; The output terminal of the active impedance matching voltage follower is connected to the input terminal of the low-voltage capacitor series-parallel combination network and the input terminal of the voltage compensation unit, respectively. The low-voltage capacitor series-parallel combination network includes multiple solid capacitors with different capacitance values, including those connected in series and parallel. The control terminal of the low-voltage capacitor series-parallel combination network is connected to the automatic voltage division ratio switching module. The automatic voltage division ratio switching module changes the total capacitance value on the low-voltage side to achieve multiple voltage division ratio switching. The voltage compensation unit outputs a corresponding compensation voltage ΔU according to the switched voltage division ratio, and superimposes the compensation voltage ΔU onto the output of the system to obtain the calibrated low-voltage side low-frequency voltage Uo.
2. The system according to claim 1, characterized in that, The value of the high-voltage side capacitor is set to a fixed value according to the rated voltage level of the power system corresponding to the low-frequency voltage Ui input to the high-voltage side being measured; wherein, the high-voltage side capacitor corresponding to the rated voltage level of the 10kV power system is 200pF, the high-voltage side capacitor corresponding to the rated voltage level of the 110kV power system is 100pF, and the high-voltage side capacitor corresponding to the rated voltage level of the 220kV power system is 50pF.
3. The system according to claim 1, characterized in that, The fixed capacitors in the low-voltage capacitor series-parallel combination network include specifications of 50nF, 100nF, 200nF and 500nF; the series and parallel connection mode of the fixed capacitors is controlled by the logic controller in the voltage division ratio automatic switching module to realize multiple voltage division ratio outputs.
4. The system according to claim 1, characterized in that, The active impedance matching voltage follower includes two operational amplifiers UA and UB with identical parameters, as well as resistors R1, R2, and capacitor C0. The positive input terminal of the operational amplifier UA is connected to the input voltage Uix of the active impedance matching voltage follower, and the output terminal of the operational amplifier UA is connected to the output voltage Uox of the active impedance matching voltage follower, and is connected to the series resistors R1 and R2. The negative input terminal of the operational amplifier UA is connected to the negative input terminal of the operational amplifier UB via resistors R1 and R2, and the positive input terminal of the operational amplifier UB is connected to the output voltage Uox of the active impedance matching voltage follower. The active impedance-matched voltage follower achieves low-deviation voltage following and electrical isolation output between the preceding and following stages.
5. The system according to claim 4, characterized in that, The output voltage Uox of the active impedance matching voltage follower and the voltage division ratio signal output by the automatic voltage division ratio switching module are processed and then input to the voltage compensation unit. The voltage compensation unit outputs a compensation voltage ΔU and superimposes it onto the output of the system to obtain the calibrated low-voltage side low-frequency voltage Uo.
6. A method for measuring the proportion of low-frequency voltage with multiple voltage divider ratios, characterized in that, The method includes establishing a measurement system, which includes: a two-stage capacitor voltage divider structure, a low-voltage capacitor series-parallel combination network, an automatic voltage divider ratio switching module, an active impedance matching voltage follower, and a voltage compensation unit. The two-stage capacitor voltage divider structure includes a high-voltage side capacitor and a low-voltage side capacitor; the first terminal of the high-voltage side capacitor is connected to the high-voltage side input low-frequency voltage Ui, and the low-voltage side capacitor is connected to the input terminal of the active impedance matching voltage follower; The output terminal of the active impedance matching voltage follower is connected to the input terminal of the low-voltage capacitor series-parallel combination network and the input terminal of the voltage compensation unit, respectively. The low-voltage capacitor series-parallel combination network includes multiple solid capacitors with different capacitance values, including those connected in series and parallel. The control terminal of the low-voltage capacitor series-parallel combination network is connected to the automatic voltage division ratio switching module. The automatic voltage division ratio switching module changes the total capacitance value on the low-voltage side to achieve multiple voltage division ratio switching. The voltage compensation unit outputs a corresponding compensation voltage ΔU based on the switched voltage division ratio, and the compensation voltage ΔU is superimposed on the output of the system to obtain the calibrated low-voltage side low-frequency voltage Uo.
7. The method according to claim 6, characterized in that, The value of the high-voltage side capacitor is set to a fixed value according to the rated voltage level of the power system corresponding to the low-frequency voltage Ui input to the high-voltage side under test; wherein, the high-voltage side capacitor corresponding to the rated voltage level of the 10kV power system is 200pF, the high-voltage side capacitor corresponding to the rated voltage level of the 110kV power system is 100pF, and the high-voltage side capacitor corresponding to the rated voltage level of the 220kV power system is 50pF.
8. The method according to claim 6, characterized in that, The fixed capacitors in the low-voltage capacitor series-parallel combination network are configured with specifications including 50nF, 100nF, 200nF and 500nF; the series-parallel connection mode of the fixed capacitors is controlled by the logic controller in the voltage division ratio automatic switching module to achieve multiple voltage division ratio outputs.
9. The method according to claim 6, characterized in that, The active impedance matching voltage follower includes two operational amplifiers UA and UB with identical parameters, as well as resistors R1, R2, and capacitor C0. Connect the positive input terminal of the operational amplifier UA to the input voltage Uix of the active impedance matching voltage follower, connect the output terminal of the operational amplifier UA to the output voltage Uox of the active impedance matching voltage follower, and connect it to the series resistors R1 and R2. Connect the negative input terminal of the operational amplifier UA to the negative input terminal of the operational amplifier UB via resistors R1 and R2, and connect the positive input terminal of the operational amplifier UB to the output voltage Uox of the active impedance matching voltage follower. The active impedance-matched voltage follower enables low-deviation voltage following and electrical isolation output between the preceding and following stages.
10. The method according to claim 9, characterized in that, The output voltage Uox of the active impedance matching voltage follower and the voltage division ratio signal output by the automatic voltage division ratio switching module are processed and input into the voltage compensation unit. The voltage compensation unit outputs a compensation voltage ΔU and superimposes it onto the output of the system to obtain the calibrated low-voltage side low-frequency voltage Uo.