Isolated wide-band low-temperature drift intelligent voltage sensing device with multiple high-voltage protection

Abstract

The application discloses a kind of isolated wideband low temperature drift intelligent voltage sensing device with multiple high voltage protection, it relates to high voltage measurement and digital monitoring field.The device includes: high voltage fuse, for receiving and transmitting high voltage signal, and through fusing cutting off high voltage passage;High voltage arm, first end is connected with high voltage fuse;Low voltage arm, first end is connected with the second end of high voltage arm, second end is connected with reference end;Transient voltage suppressor, parallel with low voltage arm, for providing clamping voltage;Gas discharge tube, parallel with low voltage arm, for discharging surge energy;Buffer amplifier, connected with low voltage arm, for buffering and amplifying the signal output by low voltage arm;Isolation amplifier, connected with buffer amplifier, for isolating and amplifying the signal after buffering and amplifying and outputting differential signal.The application improves the safety of equipment use and the accuracy of measurement result.

Description

Technical Field

[0001] This invention relates to the field of high voltage measurement and digital monitoring, specifically to an isolated wideband low-temperature drift intelligent voltage sensing device with multiple high voltage protections. Background Technology

[0002] In power system condition monitoring, voltage signals in the DC to 100kHz frequency band contain important insulation status information, such as transient overvoltages caused by partial discharge and oscillating voltages generated by switching operations. Accurate measurement and digital transmission of these signals are of great significance to online monitoring systems.

[0003] However, existing high-frequency voltage measurement schemes have the following main shortcomings.

[0004] 1. Traditional voltage transformers (PTs): They are large in size and have a narrow bandwidth. Their upper frequency limit is usually below 10kHz, making them unable to measure voltage signals above 10kHz.

[0005] 2. Existing isolated voltage sensors: Most rely solely on a single isolation device (such as an optocoupler or isolation amplifier) ​​for protection, lacking multi-level protection designs against high-voltage capacitor failure. Once a short-circuit fault occurs in the circuit preceding the isolation device, the high voltage may still form an uncontrollable discharge path through the power line or ground line.

[0006] 3. Lack of frequency measurement: Most voltage sensors only output amplitude information and cannot provide frequency information at the same time. Frequency is an important parameter for determining the type and severity of partial discharge.

[0007] 4. Existing RC voltage divider sensors use fixed RC elements and lack active compensation methods for element temperature drift. The voltage divider ratio drift can reach more than 1% across the entire temperature range, which limits their application in high-precision measurement scenarios with a wide temperature range.

[0008] Therefore, there is an urgent need for an intelligent sensor that has multiple high-voltage protections, reliable electrical isolation, can directly measure the voltage of high-voltage conductors of tens of thousands of volts in the full frequency band of DC to 100kHz, and has low temperature drift in a wide temperature range. Summary of the Invention

[0009] This invention addresses the shortcomings of existing high-frequency voltage measurement solutions by providing an isolated, wide-band, low-temperature drift intelligent voltage sensing device with multiple high-voltage protections, thereby improving the safety of equipment use and the accuracy of measurement results.

[0010] The present invention is achieved through the following technical solution.

[0011] This invention provides an isolated, wide-band, low-temperature drift intelligent voltage sensing device with multiple high-voltage protections, the device comprising:

[0012] High-voltage fuses are used to receive and transmit high-voltage signals and to cut off the high-voltage path by melting.

[0013] A high-voltage arm, the first end of which is connected to the high-voltage fuse;

[0014] The low-pressure arm has a first end connected to the second end of the high-pressure arm, and the second end is connected to the reference end.

[0015] A transient voltage suppressor, connected in parallel with the low-voltage arm, is used to provide a clamping voltage;

[0016] A gas discharge tube, connected in parallel with the low-pressure arm, is used to discharge surge energy;

[0017] A buffer amplifier, connected to the low-voltage arm, is used to buffer and amplify the signal output from the low-voltage arm.

[0018] An isolation amplifier, connected to the buffer amplifier, is used to isolate and amplify the buffered signal and output a differential signal.

[0019] In some embodiments, the apparatus further includes:

[0020] A signal conditioning circuit, connected to the isolation amplifier, is used to convert the differential signal into a single-ended signal and filter the single-ended signal;

[0021] The first analog-to-digital converter circuit is connected to the signal conditioning circuit and is used to sample and convert the filtered single-ended signal into a digital signal.

[0022] The microprocessor, connected to the first analog-to-digital converter circuit, is used to process the received digital signal to obtain the amplitude and frequency information of the high-voltage signal.

[0023] In some embodiments, the high-voltage arm includes a plurality of high-voltage resistors connected in series, and each high-voltage resistor is connected in parallel with a high-voltage capacitor.

[0024] In some embodiments, the low-voltage arm includes: an adjustable resistor and a capacitor connected in parallel with the adjustable resistor, wherein the adjustable resistor includes: a precision fixed resistor and a digital potentiometer connected in series with the precision fixed resistor.

[0025] In some embodiments, the device further includes a temperature sensor for measuring ambient temperature, and the microprocessor adjusts the tap position of the digital potentiometer based on a preset temperature-compensation table and the ambient temperature.

[0026] In some embodiments, the device further includes a second analog-to-digital converter circuit and a high-speed digital isolator, wherein the second analog-to-digital converter circuit is connected to the buffer amplifier and converts the analog signal output by the buffer amplifier into a digital signal, and the high-speed digital isolator receives the digital signal and transmits it to the microprocessor.

[0027] In some embodiments, the device further includes: an isolated CAN transceiver connected to the microprocessor, for receiving amplitude and frequency information of the high-voltage signal output by the microprocessor and transmitting it to an external monitoring system via the CAN bus.

[0028] In some embodiments, the device further includes: an optical fiber transmission module connected to the microprocessor, for receiving amplitude and frequency information of the high-voltage signal output by the microprocessor and transmitting it to an external monitoring system via optical fiber.

[0029] In some embodiments, the device further includes a low-voltage power supply module and an isolation power supply, wherein the low-voltage power supply module is used to convert an external power supply into a DC operating power supply for directly supplying power to the low-voltage side circuit, and the DC operating power supply supplies power to the high-voltage side circuit through the isolation power supply.

[0030] In some embodiments, the device includes at least three high-voltage input channels consisting of the high-voltage fuse, the high-voltage arm, and the low-voltage arm to achieve multi-channel synchronous measurement.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects: through the distributed withstand voltage design of the high voltage fuse, high voltage arm and low voltage arm RC network, multi-level protection of overvoltage clamping, and dual isolation design of the signal path, it ensures that high voltage will not enter the low voltage side in the event of failure of any single component; by using temperature compensation technology to adjust the matching resistance of the low voltage arm, the measurement accuracy of the product in the whole temperature range is ensured. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of an isolated wideband low-temperature drift intelligent voltage sensing device with multiple high-voltage protection according to an embodiment of the present invention.

[0034] Figure 2 This is a schematic diagram illustrating the temperature adaptive compensation principle according to an embodiment of the present invention. Detailed Implementation

[0035] In the following, the terms “comprising” or “may include” as used in the various embodiments of this application indicate the presence of a function, operation, or element of the invention and do not limit the addition of one or more functions, operations, or elements. Furthermore, as used in the various embodiments of this application, the terms “comprising,” “having,” and their cognates are intended only to indicate a specific feature, number, step, operation, element, component, or combination of the foregoing and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing, or adding one or more combinations of the foregoing.

[0036] In various embodiments of this application, the expression "or" or "at least one of A and / or B" includes any combination or all combinations of the words listed simultaneously. For example, the expression "A or B" or "at least one of A and / or B" may include A, may include B, or may include both A and B.

[0037] The terms used in the various embodiments of this application (such as "first," "second," etc.) may modify various constituent elements in the various embodiments, but do not limit the corresponding constituent elements. For example, the above terms do not limit the order and / or importance of the elements. The above terms are only used for the purpose of distinguishing one element from other elements. For example, a first user device and a second user device refer to different user devices, although both are user devices. For example, without departing from the scope of the various embodiments of this application, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0038] It should be noted that if a description is made of "connecting" one component to another, then the first component can be directly connected to the second component, and a third component can be "connected" between the first and second components. Conversely, when a component is "directly connected" to another component, it can be understood that there is no third component between the first and second components.

[0039] The terminology used in the various embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the various embodiments of this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of this application pertain. The terms (such as those defined in a generally used dictionary) are to be interpreted as having the same meaning as in the context of the relevant technical field and are not to be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of this application.

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this application are only for explaining this application and are not intended to limit this application.

[0041] On the one hand, the present invention provides an isolated wideband low-temperature drift intelligent voltage sensing device with multiple high-voltage protections. Figure 1 This is a schematic diagram of a contact-type broadband intelligent voltage sensing device according to an embodiment of the present invention. (Reference) Figure 1 The voltage sensing device includes: a high-voltage fuse for receiving and transmitting high-voltage signals and cutting off the high-voltage path by melting; a high-voltage arm, the first end of which is connected to the high-voltage fuse; a low-voltage arm, the first end of which is connected to the second end of the arm, and the second end is connected to a reference terminal; a transient voltage suppressor connected in parallel with the low-voltage arm for providing clamping voltage; a gas discharge tube connected in parallel with the low-voltage arm for discharging surge energy; a buffer amplifier connected to the low-voltage arm for buffering and amplifying the signal output by the low-voltage arm; and an isolation amplifier connected to the buffer amplifier for isolating and amplifying the buffered and amplified signal and outputting a differential signal.

[0042] In some embodiments, the device further includes a low-voltage power supply module and an isolation power supply, wherein the low-voltage power supply module is used to convert an external power supply into a DC operating power supply for directly supplying power to the low-voltage side circuit, and the DC operating power supply supplies power to the high-voltage side circuit through the isolation power supply.

[0043] The following is for reference Figure 1 The structural units of the voltage sensing device are described in detail.

[0044] On the high-voltage side, tens of thousands of volts of high-voltage signals are safely and reliably introduced into the voltage sensing device through the high-voltage input terminal, while ensuring sufficient insulation between the high-voltage conductor and the grounded metal casing. For example, the high-voltage input terminal can be an insulated probe with a withstand voltage of 20kV, which is introduced into the high-voltage area of ​​the voltage sensing device through a high-voltage silicone wire.

[0045] When the high-voltage fuse is operating normally, the operating current of the sensing device is much smaller than the fuse's protective current, and the fuse acts like a conductor, having no impact on the signal. However, in the event of an extreme fault (such as a complete breakdown of the high-voltage arm capacitor leading to a short circuit and subsequent failure of current-limiting measures), the fault current increases rapidly and exceeds the protective current. The fuse then melts within hundreds of milliseconds, physically cutting off the high-voltage path and preventing the fault from escalating and causing a fire. For example, a high-voltage fuse with a rated voltage of 10kV and a rated current of 20mA can be selected and connected in series after the input terminal.

[0046] The high-voltage arm consists of multiple high-voltage resistors connected in series, with each resistor connected in parallel to a high-voltage capacitor. The high-voltage resistors handle DC and low-frequency voltage division, while the high-voltage capacitors provide low-impedance bypass for high-frequency signals, keeping the voltage division ratio flat across the entire frequency range. For example, the high-voltage arm could consist of 20 2MΩ / 10kV resistors connected in series, with each resistor connected in parallel to a 5pF / 10kV high-voltage capacitor.

[0047] The low-voltage arm consists of an adjustable resistor formed by a precision fixed resistor connected in series with a digital potentiometer. This adjustable resistor is then connected in parallel with a precision capacitor to form a topology network. The precision fixed resistor and digital potentiometer ensure accurate voltage division for DC and low-frequency signals, while the capacitor provides a low-impedance path for high-frequency signals, keeping the voltage division ratio constant within the DC to 100kHz frequency range. For example, the equivalent resistance of the low-voltage arm is constructed by connecting a precision fixed resistor (1.8kΩ) in series with a digital potentiometer. The digital potentiometer uses a rise / fall interface mode and connects to the MCU's general-purpose I / O (input / output) port. The voltage division ratio is controlled to be 20000:1 by adjusting the digital potentiometer.

[0048] Before leaving the factory, the sensor can be calibrated and the digital potentiometer tap positions recorded at multiple temperature points within the range of -40℃ to +85℃, generating a temperature-resistance compensation table stored in EEPROM (Electrically Erasable Programmable Read-Only Memory). During online operation, the MCU (Microcontroller Unit) reads the temperature sensor data in real time, looks up the table, and linearly interpolates to calculate the target tap position. It then adjusts the equivalent resistance of the low-voltage arm by controlling the digital potentiometer to compensate for the voltage division ratio drift caused by temperature changes in the RC components, ensuring the voltage division ratio remains constant across the entire temperature range. For example, referencing... Figure 2During factory calibration, the temperature sensor is placed in a precision temperature chamber and calibrated at seven temperature points: -40℃, -20℃, 0℃, 25℃, 50℃, 70℃, and 85℃. After stabilizing at each temperature point for 30 minutes, a standard voltage signal is input. The MCU automatically executes a tap search algorithm, adjusting the digital potentiometer tap position using a binary search method until the voltage division ratio recovers to the nominal value at 25℃ (error ≤ ±0.05%). The tap position is recorded and stored in the EEPROM. After all calibrations are completed, a temperature-resistance compensation table and linear interpolation coefficients between adjacent points are generated and written to the EEPROM. When using temperature sensor complementarity testing, the MCU executes a compensation process every 100ms, reads the temperature sensor value, queries the compensation table, calculates the target tap position using linear interpolation, and sends a control signal to the digital potentiometer of the low-voltage arm to adjust the tap position of the digital potentiometer, thereby adjusting the resistance of the low-voltage arm.

[0049] Transient voltage suppressor (TVS) and gas discharge tube (GDT) are connected in parallel with the low-voltage arm. When the voltage of the low-voltage node rises abnormally due to faults such as electrostatic discharge, lightning strikes or surges, TVS provides fast and precise clamping, and the gas inside GDT is ionized and conducts, providing coarse protection and surge energy discharge.

[0050] The buffer amplifier is powered by an isolated power supply, has extremely high input impedance, does not draw current from the voltage divider network to avoid load effects changing the voltage division ratio, and has extremely low output impedance, enabling it to powerfully drive the input of subsequent isolation amplifiers. For example, the buffer amplifier uses a precision operational amplifier to form a voltage follower, with extremely high input impedance that does not affect the voltage division ratio, and outputs a 0-5V analog signal to drive the isolation amplifier. It is powered by the high-voltage side of the isolated power supply.

[0051] The isolated power supply uses a miniature isolation transformer to generate an isolated +5V from the low-voltage side +5V input, which powers the high-voltage side buffer amplifier and the high-voltage end of the isolation amplifier.

[0052] The buffered and amplified signal enters the analog isolation amplifier, is transmitted across the isolation barrier to the low-voltage side, and is output as a differential signal after demodulation by the analog isolation amplifier. At the same time, it ensures complete electrical isolation between the high-voltage side and the low-voltage side.

[0053] The signal conditioning circuit is located on the low-voltage side. It converts the differential signal output by the isolation amplifier into a single-ended signal. The signal is then filtered out by a second-order active low-pass filter (cutoff frequency 150kHz) to remove high-frequency noise and aliasing components from the ADC (analog-to-digital converter) before being fed into the ADC.

[0054] The ADC performs analog-to-digital conversion at a sampling rate of 500kSPS and a resolution of 16 bits. The 500kSPS sampling rate satisfies the Nyquist sampling theorem for a 100kHz signal (5x oversampling), and the 16-bit resolution provides sufficient quantization accuracy.

[0055] The microprocessor (MCU) reads ADC data via SPI (Serial Peripheral Interface), executes RMS true value method and DFT algorithm to calculate amplitude and frequency, and packages information such as voltage amplitude, frequency, timestamp, and sensor status into CAN 2.0B extended frames, which are then sent to the CAN bus through an isolated CAN transceiver.

[0056] The external monitoring system receives data frames from the CAN bus, parses out voltage amplitude and frequency information, and uses them for power equipment condition monitoring and fault diagnosis.

[0057] The low-voltage power supply module generates +5V and +3.3V from an external +12V or +24V input to power the various modules on the low-voltage side and the isolation power supply.

[0058] In some embodiments, a separate ADC chip is placed after the buffer amplifier on the high-voltage side to directly convert the analog signal into a digital quantity on the high-voltage side; then, the SPI serial data is transmitted across the isolation barrier to the low-voltage side MCU through a high-speed digital isolator. In this way, the digital signal crosses the isolation barrier without any accuracy loss, which is suitable for application scenarios with higher amplitude accuracy requirements.

[0059] In some embodiments, due to extremely strong electromagnetic interference in some power field environments, the CAN bus may experience communication errors in strong electromagnetic environments, and long-distance transmission requires relays. Therefore, the output interface on the low-voltage side can be changed from the CAN bus to a fiber optic interface. The microprocessor sends voltage amplitude and frequency data to the fiber optic transmitting module via UART or SPI. The data is then transmitted via fiber optic to the remote receiving module (such as HFBR-2412), and then converted into electrical signals for use in the monitoring system. Fiber optic itself is an insulator, providing natural electrical isolation with an isolation withstand voltage of up to tens of kV.

[0060] Three-phase power equipment requires simultaneous measurement of the amplitude and frequency of the three-phase voltages for phase-to-phase comparison and partial discharge location. Therefore, in some embodiments, the voltage sensing device can integrate three independent high-voltage input channels, corresponding to phases A, B, and C. Each channel includes an independent high-voltage input terminal, fuse, RC voltage divider network, and GDT / TVS protection. The three channels share a single multi-channel synchronous ADC, and the microprocessor simultaneously processes the three-phase data, outputting the three-phase voltage amplitude, the frequency of each phase, and the phase-to-phase voltage difference. The three-channel data are transmitted in a time-division multiplexing manner via the same CAN bus, or distinguished by three independent CAN IDs.

[0061] In this invention, the input high-voltage signal flows sequentially through the high-voltage conductor under test, the high-voltage input terminal, the high-voltage fuse, the high-voltage arm, the low-voltage arm (including adjustable temperature drift compensation), the buffer amplifier, the analog isolation amplifier, the signal conditioning circuit, the ADC, the MCU microprocessor, the isolated CAN transceiver, and the CAN bus. External power is converted to +5V via a low-voltage power supply module to power the low-voltage side module, and the +5V is then used to power the high-voltage side module via an isolated power supply. A temperature sensor is used to test the ambient temperature, and the MCU adjusts the digital potentiometer based on the temperature sensor data using a calibration table. Through the distributed withstand voltage design of the RC network of the high-voltage fuse, high-voltage arm, and low-voltage arm, multi-level overvoltage clamping protection, and dual isolation design of the signal path, it is ensured that high voltage will not enter the low-voltage side in the event of failure of any single component. Temperature compensation technology is used to adjust the matching resistor of the low-voltage arm to ensure the measurement accuracy of the product across the entire temperature range. It is particularly suitable for direct contact measurement of high voltage signals at the tens of thousands of volts level and in the DC to 100kHz frequency band. It can safely output the amplitude and frequency of the measured voltage digitally via CAN bus and is applicable to applications such as partial discharge transient voltage measurement and high frequency harmonic monitoring in power equipment.

[0062] The present invention can achieve the following technical effects.

[0063] 1. By using a series resistor design, the high voltage is distributed to multiple units, and each resistor withstands a voltage much lower than its rated withstand voltage; the capacitor connected in parallel with each resistor provides a bypass for high-frequency signals, compensates for the influence of parasitic capacitance on the voltage division ratio, significantly reduces the probability of breakdown, and expands the operating frequency band.

[0064] 2. Extremely high safety: Through a multi-level high-voltage protection system, it is ensured that even if the voltage divider network components fail, high voltage will not enter the low-voltage side. High-voltage fuses ensure that downstream devices are not damaged when abnormal voltage signals are input. The RC network composed of the high-voltage arm and the low-voltage arm limits the operating current. GDT / TVS clamps abnormal voltages, and isolation amplifiers provide the final electrical isolation barrier. Multiple redundancies ensure the safety of personnel and equipment.

[0065] 3. Wideband flat response: The parallel resistor-capacitor voltage divider network makes the amplitude-frequency response fluctuate less than ±0.5% in the DC to 100kHz frequency band, which is better than the pure resistor voltage divider scheme.

[0066] 4. Low-voltage arm RC network and adjustable temperature drift compensation: The low-voltage arm adopts an adjustable resistor structure (precision fixed resistor and digital potentiometer in series). The MCU reads temperature sensor data in real time and dynamically adjusts the tap position of the digital potentiometer to actively compensate for the parameter drift of the RC components with temperature. Combined with the low-temperature drift selection of resistors (TCR≤±15ppm / ℃) and capacitors (NP0 / C0G dielectric, near-zero temperature coefficient), the voltage division ratio is ensured to fluctuate by less than ±0.2% over the entire temperature range of -40℃ to +85℃, which is more than an order of magnitude better than traditional fixed RC voltage divider schemes.

[0067] 5. DC component measurable: Unlike pure capacitive voltage dividers, the resistor branch provides a DC coupling path, which can measure voltage signals with DC bias.

[0068] 6. Synchronous output of amplitude and frequency: Built-in intelligent algorithm can provide the effective voltage value and frequency value of the measured signal in real time, providing richer feature quantities for partial discharge mode recognition.

[0069] 7. CAN bus digital output: The output is a CAN protocol digital signal. It adopts an isolated CAN transceiver, which has strong anti-interference ability, supports multi-sensor networking, and can be directly and safely connected to the existing power monitoring system.

[0070] When this contact-type broadband intelligent voltage sensing device is in operation, it receives and transmits high-voltage signals through a high-voltage fuse to cut off the high-voltage path by melting; it receives the high-voltage signal output by the high-voltage fuse through the high-voltage arm; it receives the high-voltage signal output by the high-voltage arm through the low-voltage arm; it processes the signal output by the low-voltage arm through a transient voltage suppressor connected in parallel with the low-voltage arm to provide clamping voltage; it processes the signal output by the low-voltage arm through a gas discharge tube connected in parallel with the low-voltage arm to discharge surge energy; it buffers and amplifies the signal output by the low-voltage arm through a buffer amplifier connected to the output terminal of the low-voltage arm; and it isolates and amplifies the signal output by the buffer amplifier through an isolation amplifier and outputs a differential signal.

[0071] Furthermore, this contact-type broadband intelligent voltage sensing device also uses a signal conditioning circuit to convert the differential signal into a single-ended signal and filter the single-ended signal; an analog-to-digital converter circuit samples and converts the single-ended signal output from the conditioning circuit to obtain a digital signal; and a microprocessor processes the received signal to obtain the amplitude and frequency information of the high-voltage signal. Simultaneously, this contact-type broadband intelligent voltage sensing device measures the ambient temperature using a temperature sensor, and the microprocessor adjusts the tap position of the digital potentiometer in the low-voltage arm based on a preset temperature-compensation table and the ambient temperature to adjust the resistance value of the low-voltage arm.

[0072] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An isolated, wide-band, low-temperature drift intelligent voltage sensing device with multiple high-voltage protections, characterized in that, The device includes: High-voltage fuses are used to receive and transmit high-voltage signals and to cut off the high-voltage path by melting. A high-voltage arm, the first end of which is connected to the high-voltage fuse; The low-pressure arm has a first end connected to the second end of the high-pressure arm, and the second end is connected to the reference end. A transient voltage suppressor, connected in parallel with the low-voltage arm, is used to provide a clamping voltage; A gas discharge tube, connected in parallel with the low-pressure arm, is used to discharge surge energy; A buffer amplifier, connected to the low-voltage arm, is used to buffer and amplify the signal output from the low-voltage arm. An isolation amplifier, connected to the buffer amplifier, is used to isolate and amplify the buffered signal and output a differential signal.

2. The apparatus according to claim 1, characterized in that, The device further includes: A signal conditioning circuit, connected to the isolation amplifier, is used to convert the differential signal into a single-ended signal and filter the single-ended signal; The first analog-to-digital converter circuit is connected to the signal conditioning circuit and is used to sample and convert the filtered single-ended signal into a digital signal. The microprocessor, connected to the first analog-to-digital converter circuit, is used to process the received digital signal to obtain the amplitude and frequency information of the high-voltage signal.

3. The apparatus according to claim 1, characterized in that, The high-voltage arm includes multiple high-voltage resistors connected in series, and each high-voltage resistor is connected in parallel with a high-voltage capacitor.

4. The apparatus according to any one of claims 1 to 3, characterized in that, The low-voltage arm includes: an adjustable resistor and a capacitor connected in parallel with the adjustable resistor. The adjustable resistor includes: a precision fixed resistor and a digital potentiometer connected in series with the precision fixed resistor.

5. The apparatus according to claim 4, characterized in that, The device further includes a temperature sensor for measuring ambient temperature, and the microprocessor adjusts the tap position of the digital potentiometer based on a preset temperature-compensation table and the ambient temperature.

6. The apparatus according to claim 2, characterized in that, The device further includes a second analog-to-digital converter circuit and a high-speed digital isolator, wherein the second analog-to-digital converter circuit is connected to the buffer amplifier and converts the analog signal output by the buffer amplifier into a digital signal, and the high-speed digital isolator receives the digital signal and transmits it to the microprocessor.

7. The apparatus according to claim 1, characterized in that, The device further includes an isolated CAN transceiver connected to the microprocessor, used to receive the amplitude and frequency information of the high-voltage signal output by the microprocessor and send it to an external monitoring system via the CAN bus.

8. The apparatus according to claim 1, characterized in that, The device further includes an optical fiber transmission module connected to the microprocessor, used to receive the amplitude and frequency information of the high-voltage signal output by the microprocessor and transmit it to an external monitoring system via optical fiber.

9. The apparatus according to claim 1, characterized in that, The device further includes a low-voltage power supply module and an isolation power supply. The low-voltage power supply module is used to convert external power into DC operating power for direct power supply to the low-voltage side circuit. The DC operating power supply supplies power to the high-voltage side circuit through the isolation power supply.

10. The apparatus according to claim 1, characterized in that, The device includes at least three high-voltage input channels consisting of the high-voltage fuse, the high-voltage arm, and the low-voltage arm, to achieve multi-channel synchronous measurement.

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