An on-line extraction device for magnetic field signals of transformer winding deformation
By designing a transformer winding signal online extraction device including sampling, filtering, superimposing voltage and current amplification modules, the problem of inaccurate sampling data of transformer winding signal in the prior art is solved, and high-fidelity signal extraction and noise suppression are realized.
Patent Information
- Application Number
- CN202211207321.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-09-30
- Publication Date
- 2025-06-17
- Estimated Expiration
- 2042-09-30
AI Technical Summary
Existing offline detection methods and diagnostic methods cannot extract transformer winding signals online with high fidelity, especially when facing high current and high potential environments, it is difficult to identify overwork frequency signals.
An online magnetic field signal extraction device for deformation of transformer windings is designed, including a sampling module, a filter module, a superimposed voltage module and a current amplification module. The sampling module induces the magnetic field signal into a current signal, the filtering module filters out the power frequency signal through a 1kHz-2MHz filtering circuit, superimposed voltage module reduces the voltage complexity, and the current amplification module converts the current signal into a voltage signal.
High-fidelity sampling of the winding signals of the operating transformer is realized, power supply noise is reduced, the problem of long response time and low resolution of the active filtering method is overcome, and signal attenuation and flooding problems in the commons + voltage amplification method is avoided.
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Figure CN115436844B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electromagnetic signal detection, and particularly to an on-line extraction device for magnetic field signals of transformer winding deformation. Background Art
[0002] The safe operation of transformers, especially extra-large power transformers, traction transformers for high-speed railways and subways, is crucial to the national economy and people's livelihood. Online monitoring of them is an inevitable trend. One way is to obtain the frequency curve of their operating state in real time. The first step in the implementation means is to non-contact induct the current signal in the winding coil through an electromagnetic coil.
[0003] When the transformer is operating, the winding current is large and the potential is high, and the transformer is directly electrically connected to other equipment in the substation and overhead transmission lines, making the existing off-line detection methods and diagnostic methods unable to be directly applied:
[0004] The currently more commonly used method of active filtering + integration will introduce power supply noise, but for power frequency response signals of about 10V, the integrator is difficult to identify the supraharmonic signals with an amplitude lower than 1mV;
[0005] The currently more commonly used method of common ground + voltage amplification will cause a great attenuation or even submergence of the useful signal.
[0006] Therefore, an on-line extraction device for magnetic field signals of transformer winding deformation is needed to ensure high-fidelity sampling of the winding signals of the operating transformer. Summary of the Invention
[0007] Embodiments of the present invention provide an on-line extraction device for magnetic field signals of transformer winding deformation to at least solve the technical problem of inaccurate sampling data of transformer winding signals in related technologies.
[0008] According to one aspect of the embodiments of the present invention, an on-line extraction device for magnetic field signals of transformer winding deformation is provided, including:
[0009] A sampling module for inducting the magnetic field signal into a current signal;
[0010] A filtering module for filtering the current signal transmitted by the sampling module as a sampling signal, and the filtering module retains the supraharmonic signal;
[0011] A superimposed voltage module for generating a voltage that is half of the single power supply voltage and superimposing the generated voltage on the filtering module; and
[0012] A current amplification module for converting and amplifying the current signal transmitted by the filtering module into a voltage signal.
[0013] Optionally, the sampling module uses a Rogowski coil to obtain a magnetic field signal.
[0014] Optionally, the sampling module includes a Rogowski coil RL and a first resistor R1. The two output terminals after the parallel connection of the Rogowski coil RL and the first resistor R1 are respectively connected to the two input terminals of the filtering module.
[0015] Optionally, the filtering module uses a 1kHz - 2MHz filtering circuit to filter out signals below 1kHz including power frequency signals and retain super power frequency signals of 1kHz - 2MHz.
[0016] Optionally, the filtering module includes: a second resistor R2, a third resistor R3, a first inductor L1, a second inductor L2, and a capacitor C1. One end of the second resistor R2 is connected to an output terminal of the sampling module, and the other end of the second resistor R2 is connected to one side of the capacitor C1 and the first inductor L1; the other side of the capacitor C1 is respectively connected to one side of the second inductor L2 and the third resistor R3; the other sides of the first inductor L1, the inductor L2, and the resistor R3 are all connected to the other output terminal of the sampling module, that is, connected to the superimposed voltage terminal.
[0017] Optionally, the superimposed voltage module includes: a single power supply, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The fourth resistor R4 and the fifth resistor R5 are connected in series to the Vcc terminal and the ground terminal of the single power supply. The middle terminal of the fourth resistor R4 and the fifth resistor R5 is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is the voltage ground terminal, and the voltage ground terminal is grounded.
[0018] Optionally, the current amplification module uses a current differential amplification circuit.
[0019] Optionally, the current differential amplification circuit includes: a seventh resistor R7, an eighth resistor R8, and a current amplifier A1. One input end of the current amplifier A1 is connected to one end of the seventh resistor R7, and the other input end of the current amplifier A1 is connected to one end of the eighth resistor R8. The other ends of the seventh resistor R7 and the eighth resistor R8 are connected to the output terminal of the filtering module, and the output terminal of the current amplifier A1 is the output Vout of the entire circuit.
[0020] Compared with the existing technologies, the present invention has the following beneficial effects:
[0021] 1. In the embodiments of the present invention, a sampling module is used to induce a magnetic field signal into an electric current signal; a filtering module filters the electric current signal transmitted by the sampling module as a sampling signal, and the filtering module retains the super-power frequency signal; a superimposed voltage module is used to generate a voltage that is half of the single-power-supply voltage and superimpose the generated voltage on the filtering module; a current amplification module converts and amplifies the electric current signal transmitted by the filtering module into a voltage signal, thereby realizing high-fidelity sampling of the signal of the operating transformer winding.
[0022] 2. The present invention reduces the voltage complexity and the noise introduced by the power supply through the generated superimposed voltage terminal.
[0023] 3. The present invention combines the superimposed voltage with passive filtering, overcoming the disadvantages of long response time and low resolution of the active filtering + integration method.
[0024] 4. The present invention overcomes the problems of signal attenuation or even drowning of the commonly used common ground + voltage amplification method through the current amplification circuit for weak sampling of the measured signal.
[0025] 5. The filtering module of the present invention adopts a 1kHz - 2MHz filtering circuit. The signals below 1kHz frequency including the power frequency signal can be filtered out through the 1kHz - 2MHz filtering circuit, while the super-power frequency signal of 1kHz - 2MHz is retained. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only one embodiment of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0027] Figure 1 FIG. 1 is a schematic structural diagram of an on-line extraction device for the magnetic field signal of transformer winding deformation according to an embodiment of the present invention;
[0028] Figure 2 FIG. 2 is a schematic diagram of the Rogowski coil response of the transformer winding coil according to an embodiment of the present invention;
[0029] Figure 3 FIG. 3 is a schematic diagram of the response of the transformer winding coil after processing the noisy signal according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0030] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.
[0031] To enable those skilled in the art to better understand the solution of this application, the following will clearly and completely describe the technical solution in the embodiments of this application in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.
[0032] It should be noted that the terms "first", "second", etc. in the description and claims of this application and the above-mentioned accompanying drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so as to implement the embodiments of this application described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.
[0033] Embodiment 1
[0034] According to an embodiment of the present invention, an embodiment of an on-line extraction device for magnetic field signals of transformer winding deformation is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. And although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.
[0035] As Figure 1 is a schematic structural diagram of an on-line extraction device for magnetic field signals of transformer winding deformation according to an embodiment of the present invention. As Figure 1 shown, the device includes: a sampling module, a filtering module, a superimposed voltage module, and a current amplification module.
[0036] Among them, the sampling module is used to induce the magnetic field signal into a current signal.
[0037] The filtering module is used to filter the current signal transmitted by the sampling module as a sampling signal, and the filtering module retains the super-power frequency signal.
[0038] The superimposed voltage module is used to generate a voltage that is half of the single power supply, i.e., Vcc supply voltage, and superimpose the generated voltage on the filtering module.
[0039] The current amplification module is used to convert and amplify the current signal transmitted by the filtering module into a voltage signal.
[0040] As an alternative embodiment, the sampling module uses a Rogowski coil to obtain a magnetic field signal.
[0041] Specifically, the sampling module includes a Rogowski coil RL and a first resistor R1. The two output terminals after the parallel connection of the Rogowski coil RL and the first resistor R1 are respectively connected to the two input terminals of the filtering module.
[0042] Among them, the DC resistance values of the Rogowski coils RL are the same to obtain the strongest magnetic field induction signal.
[0043] As an alternative embodiment, the filtering module uses a 1 kHz - 2 MHz filtering circuit to filter out signals below 1 kHz including power frequency signals and retain the super power frequency signals of 1 kHz - 2 MHz.
[0044] Specifically, the filtering module includes: a second resistor R2, a third resistor R3, a first inductor L1, a second inductor L2, and a capacitor C1. One end of the second resistor R2 is connected to one output terminal of the sampling module, and the other end of the second resistor R2 is connected to one side of the capacitor C1 and the first inductor L1; the other side of the capacitor C1 is respectively connected to one side of the second inductor L2 and the third resistor R3; the other sides of the first inductor L1, the inductor L2, and the resistor R3 are all connected to the other output terminal of the sampling module, that is, connected to the superimposed voltage terminal.
[0045] Among them, the values of the second resistor R2 and the third resistor R3 are both 100 Ω, the values of the first inductor L1 and the second inductor L2 are both 4.7 mH, and the value of the capacitor C1 is 47 uF.
[0046] As an alternative embodiment, the superimposed voltage module uses a superimposed voltage circuit.
[0047] Specifically, the superimposed voltage module includes: a single power supply, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The sixth resistor R6 and the fifth resistor R5 are connected in series to the Vcc terminal and the ground terminal of the single power supply. The middle terminal of the fourth resistor R4 and the fifth resistor R5 is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is the voltage ground terminal, and this voltage ground terminal is grounded.
[0048] Among them, the values of the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 are all 1 kΩ, and the single power supply Vcc is 12 or 15 V.
[0049] As an alternative embodiment, the current amplification module uses a current differential amplification circuit.
[0050] Specifically, the current differential amplifier circuit includes: a seventh resistor R7, an eighth resistor R8, and a current amplifier A1. One end ("+" end) of the input of the current amplifier A1 is connected to one end of the seventh resistor R7, and the other end ("-" end) of the input of the current amplifier A1 is connected to one end of the eighth resistor R8. The other ends of the seventh resistor R7 and the eighth resistor R8 are connected to the output end of the filtering module (the third resistor R3), and the output end of the current amplifier A1 is the output Vout of the entire circuit.
[0051] Among them, the values of the seventh resistor R7 and the eighth resistor R8 are both 100 Ω.
[0052] The working principle is as follows: The magnetic field signal is induced into a current signal by the sampling module; the filtering module filters the current signal transmitted by the sampling module as a sampling signal, and the filtering module retains the super-power frequency signal; the superimposed voltage module is used to generate a voltage that is half of the single power supply Vcc supply voltage and superimposes the generated voltage on the filtering module; the current amplification module converts and amplifies the current signal transmitted by the filtering module into a voltage signal, thereby realizing high-fidelity sampling of the operating transformer winding signal. The characteristic of the present invention is that the filtering circuit is superimposed on a fixed voltage. First, it can be powered by a single power supply, reducing the complexity of the power supply and the interference caused by it. Second, the integration circuit of the Rogowski coil is removed; third, current amplification is performed to improve the fidelity of the signal.
[0053] The above-mentioned on-line extraction device for the magnetic field signal of the transformer winding deformation can suppress low-frequency signals below 1 kHz while retaining signals above 1 kHz. As Figure 2 shown in the magnetic field signal sampling diagram of the Rogowski coil, the response amplitude of the power frequency signal is 10 mV, and a high-frequency signal of 200 kHz with 0.4 mV is extracted from it after being processed by the circuit of the present invention, as Figure 3 shown.
[0054] The unit described as a separate component may or may not be physically separated. The component shown as a unit may or may not be a physical unit, that is, it may be located in one place or distributed to multiple units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.
[0055] In addition, in each embodiment of the present invention, each functional unit can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.
[0056] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.
Claims
1. An on-line extraction device for magnetic field signals of transformer winding deformation, characterized in that, Comprising: A sampling module for inducing a magnetic field signal into an electric current signal; A filtering module for filtering the electric current signal transmitted by the sampling module as a sampling signal, and the filtering module retains the super power frequency signal; the filtering module includes: a second resistor R2, a third resistor R3, a first inductor L1, a second inductor L2, and a capacitor C1. One end of the second resistor R2 is connected to an output end of the sampling module, and the other end of the second resistor R2 is connected to one side of the capacitor C1 and the first inductor L1; the other side of the capacitor C1 is respectively connected to one side of the second inductor L2 and the third resistor R3; the other sides of the first inductor L1, the inductor L2, and the resistor R3 are all connected to another output end of the sampling module, that is, connected to the superimposed voltage terminal; A superimposed voltage module for generating a voltage that is half of the single power supply voltage and superimposing the generated voltage on the filtering module; A current amplification module for converting and amplifying the electric current signal transmitted by the filtering module into a voltage signal.
2. The on-line extraction device for magnetic field signals of transformer winding deformation according to claim 1, characterized in that, The sampling module uses a Rogowski coil to obtain the magnetic field signal.
3. The on-line extraction device for magnetic field signals of transformer winding deformation according to claim 1, characterized in that, The sampling module includes a Rogowski coil RL and a first resistor R1. The two output ends after the parallel connection of the Rogowski coil RL and the first resistor R1 are respectively connected to the two input ends of the filtering module.
4. The on-line extraction device for magnetic field signals of transformer winding deformation according to claim 1, characterized in that, The filtering module uses a 1kHz - 2MHz filtering circuit to filter out signals below 1kHz including the power frequency signal, and retains the super power frequency signal of 1kHz - 2MHz.
5. The on-line extraction device for magnetic field signals of transformer winding deformation according to claim 1, characterized in that, The superimposed voltage module includes: a single power supply, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The fourth resistor R4 and the fifth resistor R5 are connected in series to the Vcc terminal and the ground terminal of the single power supply. The middle terminal of the fourth resistor R4 and the fifth resistor R5 is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is the voltage ground terminal, and the voltage ground terminal is grounded.
6. The on-line extraction device for magnetic field signals of transformer winding deformation according to claim 1, characterized in that, The current amplification module uses a current differential amplification circuit.
7. The on-line extraction device for magnetic field signals of transformer winding deformation according to claim 6, characterized in that, The current differential amplification circuit includes: a seventh resistor R7, an eighth resistor R8, and a current amplifier A1. One end of the input of the current amplifier A1 is connected to one end of the seventh resistor R7, the other end of the input of the current amplifier A1 is connected to one end of the eighth resistor R8, the other ends of the seventh resistor R7 and the eighth resistor R8 are connected to the output end of the filtering module, and the output end of the current amplifier A1 is the output Vout of the entire circuit.