Hand-held pressure plate direct current voltage non-contact measurement device and measurement method

Abstract

The invention discloses a handheld pressing plate direct-current voltage non-contact measuring device and a measuring method, and belongs to the technical field of power equipment detection. The device comprises an electric field induction modulation module and a main control board. And the modulation module drives a rotary modulation disc with a hollow structure to rotate through a driving motor, performs periodic chopping modulation on an electrostatic field coupled with the fixed induction electrode, and converts the electrostatic field into an alternating signal. The main control board carries out narrowband filtering and coherent demodulation on the signal, and then calculates and displays the DC voltage to ground of the tested pressure plate. According to the invention, complete electrical isolation with a protection loop is realized, and safety risks such as short circuit are avoided; power frequency interference is effectively suppressed through dynamic modulation, and the measurement precision is improved; the device is only provided with a single power switch, operation is extremely simple, single-person rapid operation and state intelligent judgment are supported, and the operation and maintenance safety and efficiency of the transformer substation are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power equipment state detection and electrical measurement, in particular to a handheld pressing plate DC voltage non-contact measurement device and a measurement method. In particular, it relates to a portable device and its operation method for safely and quickly measuring the DC voltage between the two ends of the power pressing plate through a non-contact method, which is specially used in the field of substation protection screen cabinet. BACKGROUND

[0002] The power pressing plate, also known as a connecting plate, is a key primary equipment in the relay protection system of a substation, usually installed on the inside of the panel of the protection screen cabinet, used for switching on / off the protection function or connecting / disconnecting the outlet loop, and its state is directly related to the safe and stable operation of the power grid. In order to ensure the correctness of the protection logic, the operating and maintenance personnel must periodically measure the potential difference between the two ends of the pressing plate, usually 110V or 220V DC, to verify the correctness of the potential, judge the actual state of the pressing plate and the integrity of the loop.

[0003] At present, a digital multimeter is generally used for contact measurement on site. This method requires two people to operate in cooperation: one holds two metal probes and contacts the upper and lower terminals of the pressing plate or the terminals and the ground; the other operates the multimeter and records the readings. The voltage between the two ends needs to be measured twice, and the values are compared by manual memory. This traditional method is direct, but has the following inherent defects and safety hazards: 1. Complicated operation and prone to errors: two people are required to work together, two measurements are needed, and the values are compared manually, which is inefficient and prone to misreading and misrecording. 2. Serious safety hazards: short circuit and misoperation risk: in the dense terminal row, the sharp probe is easy to miscontact the adjacent terminal, which may cause short circuit of the DC system, protection misoperation or refusal, and serious power grid accident hazards. Equipment reverse risk: if the internal insulation of the multimeter is damaged or broken down, it may directly cause abnormal grounding of the protection loop during measurement, affecting the normal work of the protection device. Human operation risk: if the gear selection is wrong (such as misselecting the current gear or the resistance gear), it may damage the instrument or cause danger. 3. It is an invasive measurement: the probe must be in direct electrical contact with the live body, which essentially changes the operating conditions of the measured loop, which does not comply with the principle of "minimizing intervention" in electrical safety measurement.

[0004] To overcome the disadvantages of contact measurement, non-contact measurement technology has gradually attracted attention. There have been related attempts in the prior art, for example: the patent document with publication number CN115684746A discloses a hard pressure plate non-contact direct current field measurement device, which senses the electric field through an electric field sensor array arranged on the back of the pressure plate, and then judges the voltage state. Although this scheme realizes non-contact, it is based on static electric field induction and is easily disturbed by environmental constant electric field, and the signal signal-to-noise ratio and measurement accuracy may be limited in a complex cabinet environment. The patent document with publication number CN106597065A introduces a non-contact high-voltage direct-current electroscope based on MEMS technology. It uses a micro-electromechanical electric field sensor for induction and integrates a signal processing circuit. However, its design is mainly aimed at high-voltage power transmission line voltage detection, and the sensor works in a static mode, which may not be suitable for sensitivity, anti-interference ability and portability in the low-voltage, small-signal and space-limited cabinet pressure plate measurement scene. Earlier technologies such as US5363045A describe a handheld non-contact electric field detection tool, but its design is simple and mainly used for qualitative detection of automobile ignition system spark plugs, and it does not have the signal processing ability to quantitatively and accurately measure the direct current voltage, which cannot meet the strict requirements of the power system for voltage measurement accuracy.

[0005] In summary, the prior art has the following shortcomings: general non-contact measurement devices, such as high-voltage electroscope, are not suitable for fine measurement of low-voltage cabinets; non-contact schemes for pressure plates mostly use static induction principles, which need to be improved in terms of anti-interference ability and measurement accuracy; and there is still a blank in high-reliability pressure plate direct current voltage non-contact measurement devices and methods that are specifically designed for the core requirements of "handheld, single person, fast, and anti-misoperation" in field operation. SUMMARY

[0006] Based on the shortcomings of the prior art, the present application aims to solve the problems of poor safety, complicated operation, low efficiency, and susceptibility to interference in the measurement of direct current voltage of power pressure plates in transformer station protection cabinets. Specifically, the technical problem to be solved by the present application is: how to provide a handheld measurement device and method specifically for transformer station environment, which can safely, quickly, accurately, and single-person complete the measurement and display of the direct current voltage between the two ends of the pressure plate without any electrical contact with the pressure plate and its circuit, and fundamentally eliminate the risks of short circuit, misoperation, and equipment reverse power supply caused by contact measurement, while overcoming the defect of static electric field induction being susceptible to environmental interference through innovative signal modulation, and improving the measurement reliability and accuracy in complex electromagnetic environments.

[0007] The technical solution adopted by the present application is: A handheld pressure plate direct current voltage non-contact measurement device, comprising: Housing; power module, housed inside the housing; display module, housed on the surface of the housing; main control board, housed inside the housing; and electric field sensing modulation module; The electric field induction modulation module includes: a drive motor; a rotating modulation disk driven by the drive motor to rotate at a constant speed, the rotating modulation disk having a hollow structure periodically distributed along its circumference; and a fixed sensing electrode, the sensing surface of which is disposed opposite to the rotating modulation disk and electrically isolated from the main control board. When the device is brought close to the object under test with a DC potential, the rotating modulation disk periodically modulates the electrostatic field coupled to the fixed sensing electrode, so that the fixed sensing electrode generates an alternating induction signal with a frequency related to the rotation speed of the rotating modulation disk. The main control board is connected to the fixed sensing electrode to receive the alternating sensing signal, process it to calculate the DC voltage value of the object under test, and control the display module to display it.

[0008] Furthermore, the rotating modulation disk is a disc, and the hollow structure consists of N fan-shaped openings evenly distributed along the circumference, where N is an integer greater than or equal to 2; preferably N=3.

[0009] Furthermore, the rotational speed of the drive motor is configured such that the fundamental frequency of the alternating induction signal is in the range of 1 kHz to 5 kHz.

[0010] Furthermore, the housing has only one power switch; the device is configured to automatically enter the DC voltage non-contact measurement mode after the power is turned on.

[0011] Furthermore, the main control board includes a signal conditioning circuit, which includes at least a bandpass filter, the center frequency of which is matched with the modulation frequency generated by the rotation of the rotating modulation disk.

[0012] Furthermore, the fixed sensing electrode and the main control board are electrically isolated by a physical gap or an insulating layer, with the distance between the physical gap or the insulating layer being 0.5mm to 10mm.

[0013] Furthermore, the device is used for non-contact measurement of the DC voltage to ground of the power plate electrode column in a substation, with a measurement range of 0V to 300V.

[0014] A non-contact method for measuring DC voltage of a handheld pressure plate, using the aforementioned non-contact DC voltage measuring device of a handheld pressure plate; This handheld pressure plate DC voltage non-contact measurement method includes the following steps: Bring the electric field sensing modulation module of the device close to the electrode post of the power plate to be tested; The drive motor is started, causing the rotating modulation disk to rotate. The hollow structure of the rotating modulation disk periodically modulates the electrostatic field sensed by the fixed sensing electrode, thereby generating an alternating electrical signal on the fixed sensing electrode. The main control board processes the alternating electrical signal to calculate the DC voltage value of the electrode post to ground. The DC voltage value is displayed through the display module.

[0015] Furthermore, the processing of the alternating electrical signal includes: performing narrowband filtering centered on the rotation frequency of the rotating modulation disk, and extracting the signal amplitude using a coherent demodulation method, wherein the signal amplitude is proportional to the DC voltage value to ground.

[0016] Furthermore, this handheld pressure plate DC voltage non-contact measurement method also includes: Measure the DC voltage to ground of the upper and lower electrode posts of the same pressure plate respectively; Based on the voltage relationship between the upper and lower electrode posts, the engagement / disengagement status of the pressure plate is automatically determined and displayed.

[0017] Compared with the prior art, the technical solution provided by the present invention has at least the following significant beneficial effects: 1. Achieve inherent safety and completely eliminate measurement risks: Physical isolation ensures system safety. Through a fixed physical gap or insulation layer design between the inductive electrodes and the main control board, complete electrical isolation is achieved between the measuring device and the measured protection circuit. Even if any fault occurs within the device, it will not affect the high-reliability protection circuit containing the pressure plate, fundamentally solving the major safety hazard of traditional multimeters potentially "backfeeding" or causing the circuit to ground. Eliminating the risk of operational short circuits, the non-contact induction method eliminates the need for exposed metal probes, completely eliminating the risk of serious accidents such as DC system short circuits, protection malfunctions, or failures to operate due to accidental contact between probes and adjacent terminals on densely packed terminal blocks, greatly improving the safety of on-site operations.

[0018] 2. Improve measurement accuracy and anti-interference capability: Dynamic modulation overcomes the shortcomings of static induction by innovatively employing a motor-driven rotating modulation disk to periodically mechanically chop and modulate the electrostatic field, converting the difficult-to-detect DC / quasi-static electric field into an alternating signal of a specific frequency. This method effectively separates the signal from noise, significantly improving the signal-to-noise ratio. Frequency selectivity and coherent demodulation, by setting the modulation frequency far from the power frequency and its harmonics, combined with narrowband filtering and coherent demodulation methods centered on this frequency, can effectively suppress complex power frequency electromagnetic interference and stray electric fields in the field. This enables stable and accurate DC voltage measurement even in the strong electromagnetic interference environment of substations, solving the problems of existing static induction schemes being susceptible to environmental interference and having poor accuracy.

[0019] 3. Extremely simplified operation, improving operational efficiency and reliability: The "one-button" anti-misoperation design features only a power switch on the device casing, with no buttons for selecting gears, ranges, or functions. It automatically enters the preset measurement mode upon power-on, achieving "foolproof" operation and fundamentally eliminating human error and equipment damage caused by incorrect gear selection. Single-person operation is rapid; during measurement, only one person needs to hold the device and bring it close to the upper and lower terminals of the pressure plate to complete the measurement and reading, eliminating the need for two people, connecting test leads, memorizing, or comparing data. The operation process is simplified by over 50%, significantly improving the efficiency of inspection and maintenance. Intelligent status judgment automatically determines and displays "on" or "off" status by measuring and intelligently analyzing the voltage values ​​at the upper and lower terminals of the pressure plate, reducing the workload of manual interpretation and subjective errors, making the results more intuitive and reliable.

[0020] 4. Specifically designed for scene optimization, highly practical: Highly targeted, the device is specifically designed for measurement scenarios involving low-voltage DC circuit boards within substation protection cabinets. Its sensitivity, measurement distance, and structural dimensions are optimized for the confined spaces and typical voltage levels within these cabinets, making it more applicable and portable than general-purpose high-voltage detectors or multimeters. Non-invasive measurement ensures that the entire measurement process does not involve electrical contact with the circuit under test or alter its state, truly achieving online, non-destructive testing, aligning with the development direction of intelligent operation and maintenance and condition-based repair.

[0021] In summary, this invention, through its unique "mechanical chopper modulation" core mechanism, combined with a minimalist anti-misoperation design and targeted scenario optimization, successfully creates a safe, accurate, efficient, and easy-to-use dedicated measurement tool and operating method. It effectively solves the long-standing pain point of substation pressure plate voltage measurement in this specific scenario, and has significant engineering application value and market prospects. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0023] Figure 1 This is a schematic diagram of the overall disassembled structure of the handheld pressure plate voltage non-contact measuring device of the present invention; Figure 2 This is a schematic diagram of the upper shell of the handheld pressure plate voltage non-contact measuring device of the present invention; Figure 3 This is a schematic diagram of the lower shell structure of the handheld pressure plate voltage non-contact measuring device of the present invention; Figure 4 This is a schematic diagram of the mounting frame of the handheld pressure plate voltage non-contact measuring device of the present invention; Figure 5 This is a schematic diagram showing the disassembled structure of the motor assembly of the handheld pressure plate voltage non-contact measuring device of the present invention. Figure 6 This is a schematic diagram of the motor mounting bracket of the handheld pressure plate voltage non-contact measuring device of the present invention; Figure 7 This is a schematic diagram of the rotating blades of the handheld pressure plate voltage non-contact measuring device of the present invention; In the diagram, 100 is the power switch, 110 is the upper shell, 120 is the LCD screen, 130 is the electric field induction modulation module, 131 is the motor mounting bracket, 132 is the rotating blade, 133 is the motor, 134 is the electric field induction board, 140 is the mounting bracket, 150 is the main control board, 160 is the battery, and 170 is the lower shell. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1 To address the technical challenges of high measurement risk, cumbersome operation, and susceptibility to interference and insufficient accuracy of traditional non-contact solutions in DC voltage measurement of power pressure plates in substation protection cabinets, this embodiment provides a highly reliable and easy-to-operate handheld non-contact measuring device, aiming to achieve safe, accurate, and efficient single-person on-site operation.

[0026] The following is combined with Figures 1 to 7The structure of the handheld pressure plate DC voltage non-contact measuring device of this embodiment will be described in detail.

[0027] This handheld pressure plate DC voltage non-contact measuring device adopts an ergonomic handheld design, with a total length of about 160mm, a maximum diameter of about 45mm, and a weight of no more than 250g. It is suitable for one-handed operation and use in narrow spaces inside the cabinet.

[0028] 1. Housing and external components: The housing consists of an upper shell 110 and a lower shell 170 connected by snaps and screws. A sensing window is located at the front of the upper shell 110, directly opposite the internal electric field sensing modulation module 130, ensuring effective coupling with the external electric field. The power switch 100 is the only physical operation button for the handheld pressure plate DC voltage non-contact measuring device. It is a self-locking rocker switch, installed in the middle of the side of the upper shell 110 for easy thumb operation. The device is configured to automatically enter the DC voltage non-contact measurement mode upon power-on, without requiring any gear or function selection.

[0029] 2. Internal component structure and connection relationships: (1) Display module: The display module is an LCD screen 120, which is a 1.8-inch segment LCD screen. It is installed inside the upper shell 110 via a mounting bracket 140. The mounting bracket 140 is fixed to the reserved column of the upper shell 110 with screws. The LCD screen 120 is then fixed to the mounting bracket 140 via a slot and adhesive, ensuring that the display interface faces the user.

[0030] (2) Power supply module: Battery 160 uses a 3.7V, 2000mAh rechargeable lithium-ion polymer battery, which is placed in a dedicated battery compartment in the lower shell 170 and connected to the power management circuit of the main control board 150 via wires.

[0031] (3) Main control board: The main control board 150 is a double-layer PCB board, fixed to the studs inside the lower casing 170 with screws. It integrates a microprocessor such as the STM32 series; signal conditioning circuitry includes: a high-impedance input buffer, a programmable gain amplifier, a bandpass filter with a center frequency of approximately 600Hz, precision rectification and detection circuitry; a 24-bit Σ-Δ analog-to-digital converter; an LCD driver circuit; a motor drive and speed control circuit; and a battery charging management circuit. The center frequency of the bandpass filter is strictly matched to the chopping frequency of the rotating modulation disk described later.

[0032] (4) Electric field induction modulation module: This module is the core sensor for non-contact measurement, installed inside the sensing window at the front of the housing, and specifically includes: Motor mounting bracket 131: fixed to the front end of the upper housing 110 by screws.

[0033] Motor 133: Motor 133 is a miniature DC brushless motor, which is fixed at the center mounting position of motor mounting bracket 131.

[0034] Rotating blade 132, also known as rotating modulation disk, is a stainless steel disc with a diameter of 20mm and a thickness of 0.5mm, with three 120° fan-shaped hollow areas evenly distributed around its circumference. This blade is directly mounted on the output shaft of motor 133 and is driven by the motor to rotate at high speed.

[0035] The electric field sensing plate 134, i.e. the fixed sensing electrode, is a 20mm×15mm gold-plated PCB copper foil plate, which is fixed to the front end of the motor mounting bracket 131. Its sensing plane is parallel to the rotating blade 132 and maintains a gap of about 0.8–1.2mm.

[0036] Key safety design: The electric field sensing board 134 is connected to the high-impedance input terminal of the main control board 150 via a shielded signal line. To achieve complete electrical isolation, the connection line has an exposed section of approximately 4mm at the end near the main control board 150, forming a reliable air gap between it and the main control board 150. This ensures that even if a fault occurs in the internal circuitry of the device, it will not affect the protection circuit under test.

[0037] 3. Assembly: The assembly sequence of the whole machine is as follows: First, fix the main control board 150 and battery 160 to the lower shell 170; then install the motor 133, rotating blade 132 and electric field sensing plate 134 to form a sensing module; then install the fixing frame 140 and LCD screen 120; finally, fasten the upper shell 110 and lock all fasteners to complete the assembly.

[0038] Through the specific structural implementation described above, this embodiment of the device achieves: completely non-contact safe measurement with an effective measurement distance of 2–12 mm, requiring no contact with live parts during operation. Intrinsically safe isolation is ensured by the physical gap design between the electric field sensing board and the main control board, guaranteeing electrical isolation between the device and the measured secondary circuit. Extremely simplified anti-misoperation features include a single power switch for immediate measurement upon power-on, with no range selection. Excellent anti-interference capabilities are achieved by modulating the signal to a specific frequency (approximately 600 Hz) using mechanical chopping and utilizing a matching narrowband filter circuit to effectively suppress noise interference from power frequency and other sources. It meets on-site accuracy requirements, with a measurement range covering DC 0–250V, a resolution of 0.1V, and a measurement error not exceeding ±2%.

[0039] Example 2 Based on the handheld pressure plate DC voltage non-contact measuring device provided in Embodiment 1, this embodiment provides a handheld pressure plate DC voltage non-contact measuring method.

[0040] The core of this handheld pressure plate DC voltage non-contact measurement method lies in utilizing the device's unique mechanical chopper modulation mechanism and targeted signal processing flow to accurately reconstruct steady-state DC electrostatic field information into voltage readings and automatically determine the pressure plate status. The following steps describe the specific implementation process, technical principles, and objectives of this method.

[0041] Step S101, Device preparation and coupling establishment: Turn on the device power; the device will automatically initialize and enter the measurement-ready state. The operator holds the device, positioning the sensing window at the front of the housing directly opposite the electrode post of the power plate to be measured, maintaining the measurement distance. The thickness is between 2mm and 15mm, preferably between 5mm and 10mm. This step establishes an electrostatic coupling relationship between the electrode post of the charged body under test and the induction electrode inside the device through a spatial medium without making electrical contact, providing a signal source for subsequent electric field sensing.

[0042] The principle of implementation is: the DC voltage of the electrode post under test to ground An electrostatic field is established in the surrounding space. This electric field induces a corresponding charge on the fixed induction electrode 134 of the device through capacitive coupling. .

[0043] Coupling capacitor The approximation is described by the following formula: ; in, It is the vacuum permittivity; To fix the effective area of ​​the sensing electrode; The distance was measured as described above.

[0044] The formula for calculating the induced charge is: .

[0045] Step S102, Mechanical chopper modulation and AC signal generation: The main control board 150 drives the motor 133, which in turn drives the rotating modulation disk 132 to a preset stable speed. For example, rotating at a constant speed of 12,000 rpm. The periodic perforated structure on the rotating modulation disk, in this embodiment, consists of three 120° fan-shaped openings, which alternately shield and expose the fixed sensing electrode 134, thereby periodically modulating the steady-state electrostatic field coupled thereon.

[0046] Purpose and function: To convert DC / quasi-static electric field signals, which are difficult to measure directly with high precision, into alternating current signals with known frequencies that are easily amplified and processed by subsequent electronic circuits. Simultaneously, the signal frequency is set within a specific range, far removed from the mains power frequency and its harmonics. For example: fundamental frequency ,when =3, =12000rpm, =600Hz, laying the foundation for subsequent selective filtering to suppress environmental interference.

[0047] Implementation principle: The periodic blocking of the rotating modulation disk effectively reduces the effective coupling area between the fixed sensing electrode 134 and the electric field being measured. It changes periodically over time. According to the principle of electrostatic induction, the induced charge on the induction electrode changes accordingly, that is: .

[0048] because DC voltage, induced current The current flows through the input impedance of the preamplifier, thereby generating an amplitude on the fixed sensing electrode 134 that is the same as the voltage being measured. Proportional to, frequency is the chopping frequency Weak AC voltage signals of its harmonics .

[0049] Step S103, Signal conditioning and voltage value calculation: (1) The main control board 150 receives an AC signal from the fixed sensing electrode 134. Then, proceed with the following processing in sequence: High-impedance buffering and amplification: The signal is received through a buffer with an input impedance of >10~12Ω to prevent signal attenuation caused by the load effect of the signal source, and then amplified by a programmable gain amplifier.

[0050] (2) Narrowband filtering: Use the center frequency to precisely set the chopping frequency. Bandpass filters, such as switched capacitor filters, filter amplified signals, greatly attenuating noise outside the frequency band, especially 50 / 60Hz power frequency and its harmonic interference.

[0051] (3) Coherent demodulation: Coherent demodulation methods, such as phase-sensitive detection based on the lock-in amplification principle, are used to extract the signal from the filtered signal. proportional DC component This step uses a chopping frequency. Using its synchronization signal as a reference, it can effectively suppress noise that is not at the same frequency as or is unrelated to the reference signal.

[0052] (4) Modular-to-digital conversion and calculation: The demodulated DC signal Digitization is performed using a high-resolution analog-to-digital converter. The microprocessor then uses calibration coefficients pre-stored within the device. The DC voltage value to ground of the measured electrode post is calculated using a linear conversion formula. : The calibration coefficient The value is obtained through calibration using a standard voltage source at the factory, and it comprehensively reflects the device's structural parameters, circuit gain, and coupling relationship.

[0053] This step reconstructs the original DC voltage information with high fidelity and high accuracy from weak AC signals containing noise. Narrowband filtering and coherent demodulation are key to achieving strong anti-interference capabilities and high measurement accuracy in this method. To eliminate the effects of environmental drift and circuit offset, the method includes an automatic zero-point calibration step. When the device is confirmed to be far from any strong electric field source, such as during the power-on initialization phase, it automatically measures and stores the background signal value as a zero-point reference, which is automatically subtracted in subsequent measurements.

[0054] Step S104, Result Display and Status Judgment: The main control board 150 will calculate the DC voltage value The data is sent to LCD screen 120 for real-time display.

[0055] To determine the working status of the pressure plate, steps S101 to S103 need to be executed sequentially on the upper and lower electrode posts of the same pressure plate to obtain the upper voltage value. and lower voltage value .

[0056] Subsequently, the microprocessor automatically determines the state based on preset logic thresholds: like ≥ , Let the first preset threshold be, for example, 80V; and ≤ , If the second preset threshold is set, for example, 5V, then the pressure plate is determined to be in the "engaged" state.

[0057] like ≤ and ≤ , If the third preset threshold is set, such as 5V, then the pressure plate is determined to be in the "exit" state.

[0058] If neither of the above two conditions is met, an "Abnormal Status" message will be displayed.

[0059] The judgment result and the corresponding voltage value are displayed on the LCD screen.

[0060] This step provides users with intuitive measurement results and automates the logical judgment of the pressure plate status, replacing manual comparison and reasoning, further improving the ease of operation and the reliability of the results.

[0061] In summary, this handheld pressure plate DC voltage non-contact measurement method enables non-contact measurement of DC voltage from 0-300V within a distance of 2-15mm from the measured point. Typical performance characteristics include: resolution better than 0.1V, basic error not exceeding ±3% of the reading, and effective suppression of complex power frequency electromagnetic interference in substation environments. The entire process can be completed by a single person with one hand, without physical contact with live parts or selection of measurement ranges, fundamentally improving safety and operational efficiency.

[0062] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A handheld, non-contact DC voltage measuring device for pressure plates, characterized in that: The handheld pressure plate DC voltage non-contact measuring device includes: a housing; a power module disposed inside the housing; a display module disposed on the surface of the housing; a main control board disposed inside the housing; and an electric field induction modulation module; The electric field induction modulation module includes: a drive motor; a rotating modulation disk driven by the drive motor to rotate at a constant speed, the rotating modulation disk having a hollow structure periodically distributed along its circumference; and a fixed sensing electrode, the sensing surface of which is disposed opposite to the rotating modulation disk and electrically isolated from the main control board. When the device is brought close to the object under test with a DC potential, the rotating modulation disk periodically modulates the electrostatic field coupled to the fixed sensing electrode, so that the fixed sensing electrode generates an alternating induction signal with a frequency related to the rotation speed of the rotating modulation disk. The main control board is connected to the fixed sensing electrode to receive the alternating sensing signal, process it to calculate the DC voltage value of the object under test, and control the display module to display it.

2. The handheld pressure plate DC voltage non-contact measuring device according to claim 1, characterized in that, The rotating modulation disk is a disc with a hollow structure consisting of N fan-shaped openings evenly distributed along the circumference, where N is an integer greater than or equal to 2; preferably N=3.

3. The handheld pressure plate DC voltage non-contact measuring device according to claim 1, characterized in that, The rotational speed of the drive motor is configured such that the fundamental frequency of the alternating induction signal is in the range of 1 kHz to 5 kHz.

4. The handheld pressure plate DC voltage non-contact measuring device according to claim 1, characterized in that, The housing has only one power switch; the device is configured to automatically enter the DC voltage non-contact measurement mode after the power is turned on.

5. The handheld pressure plate DC voltage non-contact measuring device according to claim 1, characterized in that, The main control board includes a signal conditioning circuit, which includes at least a bandpass filter. The center frequency of the bandpass filter is matched with the modulation frequency generated by the rotation of the rotating modulation disk.

6. The handheld pressure plate DC voltage non-contact measuring device according to claim 1, characterized in that, The fixed sensing electrode is electrically isolated from the main control board through a physical gap or an insulating layer, the distance of which is 0.5mm to 10mm.

7. The handheld pressure plate DC voltage non-contact measuring device according to claim 1, characterized in that, The device is used for non-contact measurement of the DC voltage to ground of the electrode post of the power pressure plate in a substation, with a measurement range of 0V to 300V.

8. A non-contact method for measuring DC voltage using a handheld pressure plate, characterized in that, The handheld pressure plate DC voltage non-contact measuring device as described in any one of claims 1 to 7 is used; the handheld pressure plate DC voltage non-contact measuring method includes the following steps: Bring the electric field sensing modulation module of the device close to the electrode post of the power plate to be tested; The drive motor is started, causing the rotating modulation disk to rotate. The hollow structure of the rotating modulation disk periodically modulates the electrostatic field sensed by the fixed sensing electrode, thereby generating an alternating electrical signal on the fixed sensing electrode. The main control board processes the alternating electrical signal to calculate the DC voltage value of the electrode post to ground. The DC voltage value is displayed through the display module.

9. The handheld pressure plate DC voltage non-contact measurement method according to claim 8, characterized in that: The processing of the alternating electrical signal includes: performing narrowband filtering centered on the rotation frequency of the rotating modulation disk, and extracting the signal amplitude using a coherent demodulation method, wherein the signal amplitude is proportional to the DC voltage value to ground.

10. The non-contact DC voltage measurement method for handheld pressure plates according to claim 8 or 9, characterized in that: This handheld pressure plate DC voltage non-contact measurement method also includes: Measure the DC voltage to ground of the upper and lower electrode posts of the same pressure plate respectively; Based on the voltage relationship between the upper and lower electrode posts, the engagement / disengagement status of the pressure plate is automatically determined and displayed.

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