Non-contact space electric field double-signal detection device, calibration method and use method
The non-contact dual-signal detection device for spatial electric fields solves the problem that existing technologies can only detect a single electrical signal, enabling non-contact measurement and quantitative analysis. It is suitable for steady-state monitoring and transient fault diagnosis in power systems, and improves the accuracy of equipment condition assessment.
Patent Information
- Application Number
- CN202511365669.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-23
- Publication Date
- 2025-12-26
AI Technical Summary
Existing non-contact voltage measurement technology can only detect a single type of electrical signal, and cannot simultaneously meet the dual needs of steady-state monitoring and transient fault diagnosis in power systems. Furthermore, it cannot establish an accurate quantitative relationship between electric field signals and the voltage of charged bodies, which limits its application in equipment fault early warning and performance degradation analysis.
Design a non-contact dual-signal detection device for spatial electric fields, including a sensing unit, an analog front-end amplification unit, a signal separation and conditioning unit, and a power management unit. It can non-contactly couple alternating electric fields, separate and amplify power frequency and traveling wave signals, and establish the mathematical relationship between signals and voltage through calibration methods.
It achieves non-contact measurement, avoids safety hazards, is suitable for mobile inspection and rapid deployment, can simultaneously output power frequency and traveling wave signals, meets the needs of steady-state monitoring and transient fault diagnosis, and realizes rough quantitative analysis of operating voltage.
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Figure CN121208451A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of electrical equipment state monitoring and fault diagnosis, and particularly relates to a non-contact spatial electric field double-signal detection device, a calibration method and a use method. BACKGROUND
[0002] In the fields of power system operation and maintenance, electrical equipment detection, industrial production safety monitoring, etc., voltage measurement is a core and basic technical link. Usually, two common measurement methods are involved. One is contact voltage measurement, such as the commonly mentioned divider measurement method. This method needs to establish a direct or indirect physical connection between the measurement device and the high-voltage live part, and then the high voltage is reduced in proportion by the divider before detection. The other is non-contact voltage measurement, which does not need to be in direct contact with the live part, and usually uses the principle of electric field induction to obtain voltage-related information, which is suitable for some scenes where direct contact is inconvenient.
[0003] However, the existing voltage measurement methods have exposed many problems that cannot be ignored when adapting to different application scenarios. For contact voltage measurement (such as a divider), since it must be directly or indirectly connected to the high-voltage conductor, this connection method has great safety hazards in a high-voltage environment. At the same time, its installation process is very complex, requiring professional personnel to perform tedious wiring, fixing, and insulation treatment, which not only consumes a lot of time and manpower, but also may temporarily affect the normal operation of the original power system. More importantly, this fixed installation measurement method is completely unsuitable for mobile inspection or rapid deployment detection scenarios in the event of a fault. The existing non-contact voltage measurement technology also has obvious shortcomings: most of them can only measure electric field strength or detect a single type of electrical signal, either only for power frequency signals or only for high-frequency signals, and cannot meet the dual needs of steady-state monitoring (requiring stable capture of power frequency signals) and transient fault diagnosis (often accompanied by high-frequency transient signals) in power systems, making it difficult for inspection personnel to fully grasp the normal operating state of the equipment and accurately determine the fault type in one detection. In addition, most non-contact sensors can only perform qualitative measurement or relative comparison measurement (such as determining "there is an electric field" or "the electric field is stronger"), and cannot establish an accurate quantitative relationship between the detected electric field signal and the actual operating voltage of the live part, which makes the measurement results only serve as a rough reference and cannot be used for precise evaluation of the operating state of electrical equipment, greatly limiting its application in fine detection scenarios such as equipment fault warning and performance degradation analysis.
[0004] Therefore, there is an urgent need for a safe and portable monitoring device that can non-contact, synchronous perceive multiple types of signals and achieve rough voltage inversion. SUMMARY
[0005] In order to solve the problem that the existing non-contact voltage measurement technology can only detect a single type of electrical signal and cannot estimate the operating voltage of a charged body, the present application provides a non-contact spatial electric field double-signal detection device, a calibration method and a use method.
[0006] The present application is implemented by the following technical solutions: In a first aspect, the present application provides a non-contact spatial electric field double-signal detection device, comprising: An induction unit for non-contact coupling of an alternating electric field in space to obtain an electric field signal and convert it into an electrical signal; An analog front-end amplification unit for amplifying the electrical signal output by the induction unit to obtain an amplified electrical signal; A signal separation and conditioning unit for separating and processing the amplified electrical signal to output a power frequency signal and a traveling wave signal.
[0007] Preferably, the signal separation and conditioning unit comprises: A power frequency signal path for extracting a power frequency signal from the amplified electrical signal; A traveling wave signal path for extracting a traveling wave signal from the amplified electrical signal; An output unit providing two output interfaces for outputting the power frequency signal and the traveling wave signal, respectively.
[0008] Further, the power frequency signal path is composed of a first group of operational amplifiers and a low-pass filter network.
[0009] Further, the low-pass filter network comprises resistors R300, R301, R302, R303, R304, R305, capacitors C300, C301, C302, and C303, and the first group of operational amplifiers comprises a first operational amplifier and a second operational amplifier. One end of the resistor R302 is connected to the output of the analog front-end amplification unit, the other end is connected to one end of the resistor R300, one end of the resistor R304 and one end of the capacitor C300; the other end of the capacitor C300 is connected to the ground, the other end of the resistor R300 is connected to one end of the capacitor C302 and the output of the first operational amplifier, the other end of the resistor R304 and the other end of the capacitor C302 are both connected to the inverting input of the first operational amplifier, the non-inverting input of the first operational amplifier is connected to the ground, the output of the first operational amplifier is connected to one end of the resistor R303, the other end of the resistor R303 is connected to one end of the resistor R301, one end of the resistor R305 and one end of the capacitor C301; the other end of the capacitor C301 is connected to the ground, the other end of the resistor R301 is connected to one end of the capacitor C303 and the output of the second operational amplifier, the other end of the resistor R305 and the other end of the capacitor C303 are both connected to the inverting input of the second operational amplifier, the non-inverting input of the second operational amplifier is connected to the ground, and the output of the second operational amplifier is used as the output of the power frequency signal channel.
[0010] Further, the traveling wave signal channel is composed of a second group of operational amplifiers and a high-pass filter network.
[0011] Further, the high-pass filter network comprises resistors R306, R307, R308, R309, capacitors C308, C309, C310, C311 and C312, and the second group of operational amplifiers comprises a third operational amplifier and a fourth operational amplifier. One end of the capacitor C309 is connected to the output of the analog front-end amplification unit, the other end is connected to one end of the resistor 306 and one end of the capacitor 310, the other end of the capacitor 310 and one end of the resistor 308 are both connected to the non-inverting input of the third operational amplifier, the other end of the resistor 308 is connected to the ground; the other end of the resistor 306 and the inverting input of the third operational amplifier are both connected to the output of the third operational amplifier, the output of the third operational amplifier is connected to one end of the capacitor 311, the other end of the capacitor 311 is connected to one end of the resistor 309, one end of the capacitor 308 and one end of the capacitor 312, one end of the resistor 309 is connected to the ground, the other end of the capacitor 308 is connected to one end of the resistor 307 and the output of the fourth operational amplifier, the other end of the capacitor 312 and the other end of the resistor 307 are both connected to the inverting input of the fourth operational amplifier, the non-inverting input of the fourth operational amplifier is connected to the ground, and the output of the fourth operational amplifier is used as the output of the traveling wave signal channel.
[0012] Preferably, the non-contact spatial electric field dual-signal detection device further comprises a power management unit for converting an externally input 12V DC power supply into various working voltages required by the device.
[0013] In a second aspect, the application provides a calibration method of the non-contact spatial electric field dual-signal detection device, comprising: S11, placing the non-contact spatial electric field dual-signal detection device at a set distance from a charged body with a standard voltage U_standard; S12, measuring and recording the power frequency signal V_out_lf output by the signal separation and conditioning unit; S13, changing the value of the standard voltage U_standard, repeating S11 and S12, and obtaining multiple sets of data pairs (U_standard, V_out_lf); S14, establishing a calibration relationship function between the power frequency signal V_out_lf and the standard voltage U_standard of the charged body through data fitting.
[0014] In a third aspect, the application provides a use method of the non-contact spatial electric field dual-signal detection device, comprising: S21, deploying the non-contact spatial electric field dual-signal detection device at a set distance from a to-be-measured charged body, and measuring and recording the power frequency signal V_out_unknown output by the signal separation and conditioning unit; S22, substituting the power frequency signal V_out_unknown into the calibration relationship function obtained in claim 8 to calculate an estimated value U_estimated of the voltage of the to-be-measured charged body.
[0015] Preferably, the use method of the non-contact spatial electric field dual-signal detection device further comprises: measuring and recording the traveling wave signal output by the signal separation and conditioning unit, and if the traveling wave signal is a high-frequency pulse signal, determining that the charged body has a fault.
[0016] Compared with the prior art, the application has the following beneficial effects: The non-contact spatial electric field dual-signal detection device can realize non-contact measurement, avoid safety hazards that may be caused by contact measurement, and does not need to be installed without power supply, and is particularly suitable for normal online monitoring and inspection of power distribution lines, transformer station equipment, etc. At the same time, the device can synchronously output two independent signals of power frequency and traveling wave, and can simultaneously meet the dual requirements of steady-state monitoring (which needs to stably capture the power frequency signal) and transient fault diagnosis (which is often accompanied by high-frequency transient signals) in the power system. The device can simultaneously realize power frequency voltage estimation and traveling wave fault monitoring, and has the functions of state monitoring and fault diagnosis.
[0017] The calibration method provided by the application can establish a mathematical relationship between the power frequency signal output by the non-contact space electric field double-signal detection device and the standard voltage. Based on the obtained mathematical relationship, rough quantitative analysis of unknown electric field intensity is realized, and the operating voltage of the charged body is further inversely estimated. Through the innovative calibration method, the application breaks through the limitation of qualitative analysis in non-contact measurement, realizes rough quantitative analysis of the operating voltage, and greatly improves the technical value and application value. BRIEF DESCRIPTION OF DRAWINGS
[0018] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor.
[0019] Figure 1 The block diagram of the power management unit of the application; Figure 2 The circuit principle diagram of the sensing unit and the analog front-end amplification unit of the application; Figure 3 The circuit principle diagram of the power frequency signal channel of the application; Figure 4 The circuit principle diagram of the traveling wave signal channel of the application; Figure 5 The overall structure block diagram of the device of the application; Figure 6 The flow chart of the calibration method of the application; Figure 7 The relationship curve between the power frequency signal output by the non-contact space electric field double-signal detection device of the application and the standard voltage; the horizontal axis is the standard voltage, and the unit is kV; the vertical axis is the power frequency signal output by the power frequency signal channel, and the unit is mV; the solid line is the broken line graph drawn by the data in Table 1, and the dotted line is the trend graph calculated according to the broken line graph. DETAILED DESCRIPTION
[0020] The embodiments of the application are described below through specific, concrete examples, and those skilled in the art can easily understand other advantages and effects of the application from the content disclosed in the specification. The application can also be implemented or applied through other different specific embodiments, and each detail in the specification can be modified or changed based on different views and applications without departing from the spirit of the application.
[0021] It should be noted that the process equipment or device not specifically mentioned in the following examples all uses the conventional equipment or device in the art.
[0022] It is to be understood that the terms "including", "comprising", "having" and their conjugates mean "including but not limited to", e.g. a process, method, object, or apparatus that comprises a list of steps or elements is not necessarily limited to those specifically listed and can include other steps or elements not expressly listed or inherent to such process, method, object, or apparatus. Further, unless otherwise specified, the numbering of method steps or blocks is intended to identify a series of steps or blocks, not a particular order of execution, and the steps or blocks can be executed in any order or in parallel, unless otherwise specified. Changes or modifications to the relative arrangement of steps or blocks can be made without departing from the scope of the application, which is defined by the appended claims.
[0023] Reference Figure 5 The non-contact spatial electric field dual-signal detection device comprises: The induction unit is used for non-contact coupling of the alternating electric field in the space to obtain an electric field signal and convert it into an electric signal. The analog front-end amplification unit is used for common-mode rejection ratio (CMRR) amplification of the electric signal output by the induction unit to obtain an amplified electric signal. The signal separation and conditioning unit is used for separation processing of the amplified electric signal to output a power frequency signal and a traveling wave signal.
[0024] The non-contact spatial electric field dual-signal detection device can realize non-contact measurement, avoid safety hazards that may be caused by contact measurement, and greatly improve the measurement efficiency without complicated wiring, fixing and insulation processing. Meanwhile, the device can synchronously output two independent signals of power frequency and traveling wave, and can simultaneously meet the dual requirements of steady-state monitoring (requiring stable capture of power frequency signals) and transient fault diagnosis (often accompanied by high-frequency transient signals) in the power system.
[0025] In some preferred schemes of the present application, the induction unit is a PCB polar plate. As a specific example, reference is made to Figure 2The analog front-end amplification unit of the application comprises a resistor R200, a resistor 201, a capacitor C204, a resistor 216, a resistor 202, a resistor 203, a resistor 204, a resistor 205, a resistor 206, a resistor 207, a dial switch and an instrument amplifier; the inverting output end of the PCB polar plate is connected to one end of the resistor 200, one end of the resistor 216, one end of the capacitor C204 and the inverting input end of the instrument amplifier, the other end of the resistor 200 is grounded, the non-inverting output end of the PCB polar plate is connected to the other end of the capacitor C204, the other end of the resistor R216, one end of the resistor R201 and the non-inverting input end of the instrument amplifier, the other end of the resistor 201 is grounded, one end of the resistor 202, one end of the resistor 203, one end of the resistor 204, one end of the resistor 205, one end of the resistor 206 and one end of the resistor 207 are all connected to the first gain setting input end of the instrument amplifier, the other end of the resistor 202, the other end of the resistor 203, the other end of the resistor 204, the other end of the resistor 205, the other end of the resistor 206 and the other end of the resistor 207 are respectively connected to the pins 12, 11, 10, 9, 8 and 7 of the dial switch, the pins 1, 2, 3, 4, 5 and 6 corresponding to the pins 12, 11, 10, 9, 8 and 7 are all connected to the second gain setting input end of the instrument amplifier; the output end of the instrument amplifier is connected to the signal separation and conditioning unit.
[0026] The analog front-end amplification unit of the application amplifies the input weak electric signal and provides a signal with a suitable amplitude for the subsequent signal separation and conditioning unit.
[0027] In some preferred embodiments of the application, the signal separation and conditioning unit comprises: A power frequency signal path (low frequency path) for extracting a power frequency signal (such as 50 / 60Hz) from the amplified electric signal and outputting S_LF_OUT; A traveling wave signal path (high frequency path) for extracting a traveling wave signal from the amplified electric signal and outputting S_HF_OUT; An output unit providing two independent output interfaces for outputting the power frequency signal and the traveling wave signal respectively.
[0028] The S_LF_OUT voltage signal amplitude (V_out_lf) output by the power frequency signal path of the application has a linear or quantifiable function relationship with the spatial power frequency electric field intensity (E), i.e. V_out_lf = f(E).
[0029] In some embodiments of the present application, the power frequency signal path is composed of a first group of operational amplifiers and a low-pass filter network.
[0030] Specifically, referring to Figure 3 , the low-pass filter network includes resistors R300, R301, R302, R303, R304, R305, capacitors C300, C301, C302, and C303, and the first group of operational amplifiers includes a first operational amplifier and a second operational amplifier. One end of resistor R302 is connected to the output of the analog front-end amplification unit, and the other end is connected to one end of resistor R300, one end of resistor R304, and one end of capacitor C300; the other end of capacitor C300 is connected to ground, the other end of resistor R300 is connected to one end of capacitor C302 and the output terminal of the first operational amplifier, the other end of resistor R304 and the other end of capacitor C302 are both connected to the inverting input terminal of the first operational amplifier, the non-inverting input terminal of the first operational amplifier is connected to ground, the output terminal of the first operational amplifier is connected to one end of resistor R303, the other end of resistor R303 is connected to one end of resistor R301, one end of resistor R305, and one end of capacitor C301; the other end of capacitor C301 is connected to ground, the other end of resistor R301 is connected to one end of capacitor C303 and the output terminal of the second operational amplifier, the other end of resistor R305 and the other end of capacitor C303 are both connected to the inverting input terminal of the second operational amplifier, the non-inverting input terminal of the second operational amplifier is connected to ground, and the output terminal of the second operational amplifier serves as the output terminal of the power frequency signal path.
[0031] The input of the power frequency signal path passes through a low-pass filter network composed of resistors and capacitors first, filters out high-frequency components, and only allows power frequency (such as 50 / 60 Hz) signals to pass through, then the signal enters an operational amplifier for amplification, and finally outputs a power frequency signal S_LF_OUT. The power frequency signal path can effectively extract and amplify power frequency signals.
[0032] In some embodiments of the present application, the traveling wave signal path is composed of a second group of operational amplifiers and a high-pass filter network.
[0033] Specifically, referring to Figure 4 , the high-pass filter network includes resistors R306, R307, R308, R309, capacitors C308, C309, C310, and C311, and the second group of operational amplifiers includes a third operational amplifier and a fourth operational amplifier. One end of the capacitor C309 is connected to the output of the analog front-end amplification unit, the other end is connected to one end of the resistor 306 and one end of the capacitor 310, the other end of the capacitor 310 and one end of the resistor 308 are both connected to the non-inverting input terminal of the third operational amplifier, the other end of the resistor 308 is connected to the ground; the other end of the resistor 306 and the inverting input terminal of the third operational amplifier are both connected to the output terminal of the third operational amplifier, the output terminal of the third operational amplifier is connected to one end of the capacitor 311, the other end of the capacitor 311 is connected to one end of the resistor 309, one end of the capacitor 308 and one end of the capacitor 312, one end of the resistor 309 is connected to the ground, the other end of the capacitor 308 is connected to one end of the resistor 307 and the output terminal of the fourth operational amplifier, the other end of the capacitor 312 and the other end of the resistor 307 are both connected to the inverting input terminal of the fourth operational amplifier, the non-inverting input terminal of the fourth operational amplifier is connected to the ground, and the output terminal of the fourth operational amplifier is used as the output terminal of the traveling wave signal path.
[0034] The input of the traveling wave signal path is first filtered by a high-pass filter network composed of capacitors and resistors, and low-frequency components are filtered out to allow high-frequency transient signals such as traveling waves to pass smoothly. Then, the signal is amplified by an operational amplifier, and the final output is a traveling wave signal S_HF_OUT, thereby achieving extraction and amplification of high-frequency transient signals.
[0035] In some preferred embodiments of the present application, the non-contact spatial electric field double-signal detection device further comprises a power management unit for converting an externally input 12V DC power supply into a plurality of stable operating voltages required by internal components of the device.
[0036] Specifically, the plurality of stable operating voltages include +5V, -5V, +3.3V, and -3.3V. Figure 1 The power management unit at least includes a common-mode filter, a protection unit, a first voltage stabilizer, a negative voltage charge pump, a second voltage stabilizer, and a third voltage stabilizer. The output terminal of the common-mode filter is connected to the input terminal of the protection unit, the output terminal of the protection unit is connected to the input terminal of the first voltage stabilizer, the first output terminal of the first voltage stabilizer is connected to the input terminal of the negative voltage charge pump, the output terminal of the negative voltage charge pump is connected to the input terminal of the third voltage stabilizer, and the second output terminal of the first voltage stabilizer is connected to the input terminal of the second voltage stabilizer. The common-mode filter is used to eliminate switching interference specific to the power supply. The protection unit is used for overcurrent, surge, and reverse connection protection. The first voltage stabilizer is used to convert the 12V DC power supply into a +5V power supply, the negative voltage charge pump is used to convert the +5V power supply into a -5V power supply, the second voltage stabilizer is used to convert the +5V power supply into a +3.3V power supply, and the third voltage stabilizer is used to convert the -5V power supply into a -3.3V power supply.
[0037] The first power input end of the instrument amplifier is connected with a +3.3V power supply, the second power input end is connected with a -3.3V power supply; the first power input end of the first operational amplifier is connected with a +3.3V power supply, the second power input end is connected with a -3.3V power supply; the first power input end of the third operational amplifier is connected with a +3.3V power supply, the second power input end is connected with a -3.3V power supply.
[0038] The non-contact space electric field double-signal detection device has high cost performance.
[0039] Reference Figure 6 The calibration method of the non-contact space electric field double-signal detection device comprises: S11, placing the non-contact space electric field double-signal detection device at a set distance from a charged body with a standard voltage U_standard (such as 10kV, 35kV...) in a standard test environment (such as a high-voltage laboratory); S12, measuring and recording the power frequency signal V_out_lf output by the signal separation and conditioning unit; S13, changing the value of the standard voltage U_standard, repeating S11 and S12, and obtaining multiple sets of data pairs (U_standard, V_out_lf); S14, establishing a calibration relationship function or calibration curve between the power frequency signal V_out_lf and the standard voltage U_standard of the charged body through data fitting (such as linear fitting, polynomial fitting).
[0040] The calibration relationship function can be simplified as V_out_lf = k * U_standard + b (linear model) or other more accurate models.
[0041] Based on the non-contact space electric field double-signal detection device and the calibration results, the application provides a use method of the non-contact space electric field double-signal detection device, comprising: S21, deploying the non-contact space electric field double-signal detection device at a set distance from a to-be-measured charged body, and measuring and recording the power frequency signal V_out_unknown output by the signal separation and conditioning unit.
[0042] S22, substituting the power frequency signal V_out_unknown into the calibration relationship function obtained by the above calibration method to obtain U_estimated = f -1(V_out_unknown) (for the linear model, namely U_estimated =(V_out_unknown – b) / k) to calculate the estimated value of the voltage of the charged body U_estimated.
[0043] The method further comprises: measuring and recording the traveling wave signal (S_HF_OUT) output by the signal separation and conditioning unit, and if the traveling wave signal is a high-frequency pulse signal, determining that the charged body may have a transient fault event such as partial discharge.
[0044] Embodiment In a standard test environment (such as a high-voltage laboratory), the non-contact spatial electric field dual-signal detection device is placed 1.5 m below the charged body with a standard voltage U_standard, and the power frequency signal V_out_lf output by the signal separation and conditioning unit is measured and recorded; the value of the standard voltage U_standard is changed, and multiple sets of data pairs (U_standard, V_out_lf) are obtained, and the specific data are shown in Table 1. From the linear relationship between V_out_lf and U_standard, the linear model is obtained as follows: Figure 7 It can be seen that V_out_lf and U_standard are basically in a linear relationship.
[0045] Table 1: Calibrated experimental data
[0046] The non-contact spatial electric field dual-signal detection device is deployed on a support 1.5 m high below a power distribution line with an unknown voltage.
[0047] After the non-contact spatial electric field dual-signal detection device is powered on, the output voltage V_out_unknown of S_LF_OUT is measured. V_out_unknown is substituted into the calibration relationship function to calculate U_estimated. According to this, the current operating voltage of the line can be roughly judged, which is consistent with the expected voltage grade.
[0048] If periodic high-frequency pulses are monitored from S_HF_OUT, it can be inferred that there may be insulation defects leading to partial discharge at some place of the line.
Claims
1. A non-contact dual-signal detection device for spatial electric fields, characterized in that, include: The sensing unit is used to non-contactly couple alternating electric fields in space, obtain electric field signals, and convert them into electrical signals. The analog front-end amplification unit is used to amplify the electrical signal output by the sensing unit to obtain an amplified electrical signal; The signal separation and conditioning unit is used to separate and process the amplified electrical signal, and output the power frequency signal and the traveling wave signal.
2. The non-contact spatial electric field dual-signal detection device according to claim 1, characterized in that, The signal separation and conditioning unit includes: The power frequency signal path is used to extract the power frequency signal from the amplified electrical signal; The traveling wave signal path is used to extract the traveling wave signal from the amplified electrical signal; The output unit provides two output interfaces, which output power frequency signals and traveling wave signals respectively.
3. The non-contact spatial electric field dual-signal detection device according to claim 2, characterized in that, The power frequency signal path consists of a first group of operational amplifiers and a low-pass filter network.
4. The non-contact spatial electric field dual-signal detection device according to claim 3, characterized in that, The low-pass filter network includes resistors R300, R301, R302, R303, R304, and R305, and capacitors C300, C301, C302, and C303. The first group of operational amplifiers includes a first operational amplifier and a second operational amplifier. One end of resistor R302 is connected to the output of the analog front-end amplifier unit, and the other end is connected to one end of resistor R300, one end of resistor R304, and one end of capacitor C300. The other end of capacitor C300 is grounded. The other end of resistor R302 is connected to one end of capacitor C302 and the output of the first operational amplifier. The other ends of resistor R304 and capacitor C302 are both connected to the inverting input of the first operational amplifier. The non-inverting input of the first operational amplifier is grounded. The output of the first operational amplifier is connected to one end of resistor R303. The other end of resistor R303 is connected to one end of resistor R301, one end of resistor R305, and one end of capacitor C301. The other end of capacitor C301 is grounded. The other end of resistor R301 is connected to one end of capacitor C303 and the output of the second operational amplifier. The other ends of resistor R305 and capacitor C303 are both connected to the inverting input of the second operational amplifier. The non-inverting input of the second operational amplifier is grounded. The output of the second operational amplifier serves as the output of the power frequency signal path.
5. The non-contact spatial electric field dual-signal detection device according to claim 2, characterized in that, The traveling wave signal path consists of a second set of operational amplifiers and a high-pass filter network.
6. The non-contact spatial electric field dual-signal detection device according to claim 5, characterized in that, The high-pass filter network includes resistors R306, R307, R308, and R309, and capacitors C308, C309, C310, C311, and C312. The second group of operational amplifiers includes a third operational amplifier and a fourth operational amplifier. One end of capacitor C309 is connected to the output of the analog front-end amplifier unit, and the other end is connected to one end of resistor 306 and one end of capacitor 310. The other end of capacitor 310 and one end of resistor 308 are both connected to the non-inverting input of the third operational amplifier, and the other end of resistor 308 is grounded. The other end of resistor 306 and the inverting input of the third operational amplifier are both connected to the output of the third operational amplifier. The output of the third operational amplifier is connected to one end of capacitor 311. The other end of capacitor 311 is connected to one end of resistor 309, one end of capacitor 308, and one end of capacitor 312. One end of resistor 309 is grounded. The other end of capacitor 308 is connected to one end of resistor 307 and the output of the fourth operational amplifier. The other end of capacitor 312 and the other end of resistor 307 are both connected to the inverting input of the fourth operational amplifier. The non-inverting input of the fourth operational amplifier is grounded. The output of the fourth operational amplifier serves as the output of the traveling wave signal path.
7. The non-contact spatial electric field dual-signal detection device according to claim 1, characterized in that, It also includes a power management unit, which converts an externally input 12V DC power supply into various operating voltages required by the device.
8. The calibration method for the non-contact dual-signal spatial electric field detection device according to any one of claims 1 to 7, characterized in that, include: S11, the non-contact spatial electric field dual-signal detection device is placed at a set distance from a charged body with a standard voltage U_standard; S12, Measure and record the power frequency signal V_out_lf output by the signal separation and conditioning unit; S13, change the value of the standard voltage U_standard, repeat S11 and S12, and obtain multiple sets of data pairs (U_standard, V_out_lf). S14. By fitting data, establish the calibration relationship function between the power frequency signal V_out_lf and the standard voltage U_standard of the charged body.
9. A method of using the non-contact dual-signal spatial electric field detection device according to any one of claims 1 to 7, characterized in that, include: S21, Deploy the non-contact spatial electric field dual-signal detection device at a set distance from the charged body to be tested, and measure and record the power frequency signal V_out_unknown output by the signal separation and conditioning unit; S22, Substitute the power frequency signal V_out_unknown into the calibration relationship function obtained in claim 8 to calculate the estimated value U_estimated of the voltage of the charged body under test.
10. The method of using the non-contact spatial electric field dual-signal detection device according to claim 9, characterized in that, Also includes: Measure and record the traveling wave signal output by the signal separation and conditioning unit. If the traveling wave signal is a high-frequency pulse signal, it is determined that there is a fault in the charged body.