Sensor and method for monitoring high altitude casing equipment signals

Abstract

The application relates to the technical field of power equipment monitoring, in particular to a sensor and a method for monitoring high-altitude sleeve pipe equipment signals. The sensor comprises a shell formed with an accommodation space, a measuring module arranged in the accommodation space and a circuit module. The shell is a flexible multilayer composite structure, the measuring module comprises AgNFs multiplex electrodes, and can realize synchronous acquisition and processing of ultrasonic, pressure and UHF signals. The circuit module can perform filtering, differential amplification, impedance matching and phase compensation processing on the three signals, and can effectively solve the problems of signal crosstalk and amplification distortion.

Description

Technical Field

[0001] This invention relates to the field of power equipment monitoring technology, and more specifically to sensors and methods for monitoring signals of high-altitude bushing equipment. Background Technology

[0002] High-altitude bushing equipment, such as rubber-impregnated paper bushings and high-altitude bushings for gas-insulated switchgear (GIS), has become core equipment in high-altitude power systems due to its excellent insulation strength and arc-extinguishing performance. Its operational status directly affects the safety and stability of the power grid. The air pressure within the gas chamber of high-altitude bushing equipment, the ultrasonic signals (20~200kHz) generated by partial discharge, and the UHF electromagnetic signals (300MHz~3GHz) are key parameters reflecting the equipment's operating status. Abnormal air pressure (too high or too low) directly affects the insulation performance of high-altitude bushing equipment and may even lead to gas chamber seal failure. The ultrasonic and UHF signals generated by partial discharge can accurately locate insulation defects in high-altitude bushing equipment and predict equipment failure risks in advance.

[0003] However, existing sensors and monitoring methods for signal monitoring of high-altitude casing equipment suffer from problems such as rigid structure, poor installation adaptability, low integration of multi-parameter monitoring, and imbalance between corrosion resistance and mechanical strength, which seriously restrict the monitoring effect and the operation and maintenance safety of high-altitude casing equipment. Summary of the Invention

[0004] This invention provides a sensor and monitoring method for monitoring signals of high-altitude casing equipment. Through flexible multilayer composite structure integration, multiplexing of three functions of multiplexed electrodes, wideband three-channel signal processing, and pressure quantification for precise calibration, it achieves synchronous and precise monitoring of three parameters: ultrasonic (20~200kHz), pressure (0~1.5MPa), and UHF electromagnetic (300MHz~3GHz), thus overcoming many shortcomings of existing technologies.

[0005] On one hand, a sensor for monitoring signals from high-altitude casing equipment is provided, comprising a housing made of flexible material, a measurement module, and a circuit module. The housing forms a receiving space within which both the measurement module and the circuit module are housed. The outer side of the housing is coated with a flexible silicone adhesive layer to achieve a gapless fit against the inner wall of the air chamber of the high-altitude casing equipment. The measurement module is used to simultaneously acquire ultrasonic signals, barometric pressure signals, and UHF electromagnetic signals. The circuit module is connected to the electrode signals of the measurement module and is used to separate, amplify, and condition the ultrasonic signals, barometric pressure signals, and UHF electromagnetic signals.

[0006] On the one hand, a method for monitoring signals of high-altitude casing equipment is provided, including the following steps:

[0007] S1, attach the sensor to the inner wall of the gas chamber, and use the measurement module to synchronously convert the pressure change of the gas chamber, the ultrasonic signal generated by the partial discharge of the equipment, and the UHF electromagnetic signal into the original electrical signal.

[0008] S2, through the circuit module, separates the original electrical signal according to frequency band and performs amplification, conditioning and other enhancement processes to obtain three types of conditioned and optimized signals;

[0009] S3 converts pressure-related signals into precisely quantified air pressure values ​​through calibration, modeling, temperature correction, and repeatability verification.

[0010] S4 integrates the conditioned and optimized ultrasonic signal, UHF signal and quantified pressure value synchronously, and transmits them to external monitoring equipment through a flexible shielded cable to achieve synchronous monitoring of the three parameters.

[0011] The sensor and monitoring method of the present invention achieve the following significant technical effects through multi-dimensional technological innovation:

[0012] The flexible multi-layer composite shell has a bendable radius of curvature ≥50mm, fits seamlessly to the arc-shaped inner wall with a fit of ≥98%; the non-drilling installation design, combined with dedicated sealing terminals, minimizes leakage. This solves the problems of strong destructiveness during installation and sealing failure in existing technologies.

[0013] AgNFs multiplexed electrodes feature three-function multiplexing and three-channel signal processing, enabling synchronous acquisition and processing of ultrasonic, pressure, and UHF signals with a time synchronization error of ≤1ms. This solves the problems of complex wiring and poor synchronization of multiple devices, and enables collaborative analysis of "insulation defects-gas characteristics".

[0014] The PTFE anti-corrosion outer layer is corrosion resistant, and the AgNFs reused electrodes have stable conductivity. The fiberglass cloth reinforced inner layer makes the sensor compressive strength ≥2MPa and service life ≥8 years, solving the problem of imbalance between corrosion resistance and mechanical strength.

[0015] Through three-channel filtering, differentiated amplification, impedance matching, and phase compensation, the signal-to-noise ratio is ≥30dB, the transmission loss is ≤5%, and weak signals (UHF microvolt level) can be effectively detected, solving the problems of signal crosstalk and amplification distortion.

[0016] Porous PVDF substrates enhance deformation response sensitivity; combined with linear modeling, temperature correction, and repeatability calibration, pressure measurement errors are reduced. Temperature affects error This meets the high-precision monitoring needs of power equipment. Attached Figure Description

[0017] Figure 1 This is a diagram of the internal layered structure of the sensor provided for an embodiment.

[0018] Figure 2 This is a diagram showing the sensor installation location for an embodiment.

[0019] Figure 3 This is a schematic diagram of the sensor principle provided for an embodiment.

[0020] Figure 4 This is a schematic flowchart of a method for monitoring signals from high-altitude casing equipment, provided as an example.

[0021] Figure 5 The flowchart of step S1 provided for the embodiment is shown.

[0022] Figure 6 The flowchart of step S2 is provided for the embodiment.

[0023] Figure 7 This is a schematic diagram of step S3 provided for an embodiment.

[0024] Figure 8 The flowchart of step S4 provided for the embodiment is shown.

[0025] The labels in the diagram represent the following:

[0026] 1-AgNFs reusable electrode; 2-Porous PVDF substrate; 4-Flexible PI substrate; 5-Fiberglass cloth reinforced inner layer; 6-Silicone elastic middle layer; 7-PTFE anti-corrosion outer layer; 10-Epoxy resin insulating layer; 12-Center conductor; 13-Sensor; 14-Gas chamber; 15-Flexible shielded cable; 20-PVDF pore; 21-Shielding wire; 22-Acoustic wave; 23-Electromagnetic wave; 26-Deformed PVDF pore. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. Reagents not specifically described in detail herein are all conventional reagents and are commercially available; methods not specifically described in detail are all conventional experimental methods and can be learned from the prior art.

[0028] This embodiment provides a sensor for monitoring signals from high-altitude casing equipment, comprising a housing made of flexible material, a measurement module, and a circuit module. The housing forms a receiving space within which both the measurement module and the circuit module are housed. The outer side of the housing is coated with a flexible silicone adhesive layer to achieve a gapless fit against the inner wall of the air chamber of the high-altitude casing equipment. The measurement module is used to simultaneously acquire ultrasonic signals, barometric pressure signals, and UHF electromagnetic signals. The circuit module is connected to the electrode signals of the measurement module and is used to separate, amplify, and condition the ultrasonic signals, barometric pressure signals, and UHF electromagnetic signals. Furthermore, the sensor is led out via a flexible shielded cable 15 through a transition joint sealed terminal, without any drilling, ensuring the air chamber's sealing performance.

[0029] Specifically, the sensor is sheet-like in shape, with the housing, measurement module, and circuit module tightly stacked from top to bottom using a high-temperature resistant adhesive, leaving no air gaps (gap ≤ 0.1μm). This integrated design ensures a compact structure, fitting snugly within the compact space of the gas chamber 14. The sensor can be bent and folded to a diameter ≤ 10mm, and is inserted and installed through the existing pre-reserved interface (air replenishment interface or maintenance interface, diameter ≥ 8mm) of the high-altitude casing equipment. After adjusting its posture with a flexible telescopic rod, it is seamlessly bonded to the curved surface of the inner wall of the gas chamber via a flexible silicone adhesive layer on the outer side of the housing. The flexible shielded cable 15 (diameter ≤ 0.12mm) is led out through the sealed terminal of the transition joint, with a sealing gap ≤ 0.01mm, ensuring a low gas chamber leakage rate. .

[0030] In some embodiments, the shell is a flexible multi-layer composite structure, consisting of a PTFE anti-corrosion outer layer 7, a silicone elastic middle layer 6, and a fiberglass cloth reinforced inner layer 5, from the outside to the inside. The three layers are tightly bonded together with a silicone adhesive to form an overall flexible structure with a bendable radius of curvature ≥50mm and no sharp corner protrusions on the surface (rounded corner radius ≥1mm) to avoid interfering with the electric field distribution inside the air chamber.

[0031] In some embodiments, the PTFE anti-corrosion outer layer 7 is 1 mm thick and is made of polytetrafluoroethylene material (purity ≥99.9%), which has excellent corrosion resistance and shows no obvious corrosion after immersion in HF and SO2 environments for 1000 hours; at the same time, the ultrasonic mechanical wave transmission loss of polytetrafluoroethylene material is ≤0.5dB, which does not affect the normal transmission of 20~200kHz ultrasonic signals.

[0032] In some embodiments, the silicone elastic middle layer 6 is located between the PTFE anti-corrosion outer layer 7 and the fiberglass cloth reinforced inner layer 5, with a thickness of 1.5~2.5mm and a Shore hardness of 45~55A. It has good elasticity and deformation capacity, which can buffer the pressure fluctuations of the air chamber 14 and the vibration of the equipment, ensure that the sensor fits tightly with the inner wall, and enhance the overall flexibility of the housing.

[0033] In some embodiments, the fiberglass cloth reinforced inner layer 5 has a thickness of 0.3~0.7mm and uses 2~4 layers of alkali-free fiberglass cloth (weight 100~200g / m²). 2 The sensor is positioned close to the measurement module, which ensures that the overall compressive strength of the sensor is ≥2MPa, preventing it from breaking under the working pressure of 140~1.5MPa in the air chamber and improving its mechanical stability.

[0034] In some embodiments, the outer side of the housing is coated with a flexible silicone adhesive layer with a thickness of 0.5~1.5mm. The curing temperature is 20~30℃, the curing time is 20~28h, and the peel strength after curing is ≥1.5N / mm. This ensures that the sensor does not detach during long-term operation (≥8 years) in the gas chamber 14, while not affecting the flexible deformation of the housing. The overall diameter of the housing is adapted to the porous PVDF substrate 2 (diameter 8mm) to ensure uniform stress on each module and consistent bonding effect.

[0035] In some embodiments, the measurement module is located inside the housing and is stacked with the housing. It includes two AgNFs multiplexed electrodes arranged symmetrically on the top and bottom and a porous PVDF substrate 2 sandwiched between them. The three are tightly bonded together with a high-temperature resistant adhesive (epoxy resin adhesive, silicone resin adhesive or polyimide adhesive, with a temperature range of -40~180℃) without air gaps to ensure lossless signal transmission.

[0036] The AgNFs multilayer electrode employs a core-shell structure, with a core layer of PVA nanofibers (500-800 nm in diameter) and a shell layer of silver (50-100 nm in thickness). It is fabricated using an electrospinning and magnetron sputtering process, achieving a high conductivity. It possesses excellent conductivity and flexibility, and can deform synchronously with the porous PVDF substrate 2 without breaking. The electrode is circular with a diameter of 8mm and is coaxially arranged with the porous PVDF substrate 2. The structures of the two electrodes are completely symmetrical, ensuring the consistency of signal acquisition. Each AgNFs multiplexing electrode is designed with a concentric circular partition structure, including a circular capacitance detection area in the center and a ring-shaped broadband antenna area surrounding the capacitance detection area. The two are conductively connected (conduction resistance ≤10Ω), realizing three-function multiplexing.

[0037] The central capacitance detection area has a diameter of 4mm and is used to form the upper and lower plates of the parallel plate capacitor. When the air pressure changes, the porous PVDF substrate 2 deforms, causing a change in the dielectric constant, which in turn causes a change in the capacitance value, thus realizing pressure detection.

[0038] The outer broadband antenna region is 1 mm wide and has a dipole arm structure with a gradually changing width, ranging from 0.2 to 0.8 mm (gradient 0.1 to 0.2 mm / mm). The outer broadband antenna regions of the two electrodes work together to form a dipole antenna, which is used to efficiently receive 300 MHz to 3 GHz UHF electromagnetic signals and convert them into high-frequency voltage signals (signal coupling efficiency ≥ 85%). At the same time, in conjunction with the piezoelectric effect of the porous PVDF substrate 2, it collects ultrasonic induced charges and converts them into low-frequency voltage signals.

[0039] The central capacitance detection area of ​​the AgNFs multiplexed electrode corresponds to the central region of the porous PVDF substrate 2, and the peripheral broadband antenna area corresponds to the edge region of the substrate, ensuring full coverage of the contact area between the electrode and the substrate (contact area ≥ 98%), improving signal transmission efficiency, and avoiding signal distortion caused by poor contact.

[0040] In some embodiments, the porous PVDF substrate 2 is in the form of a thin sheet with a thickness of 300 μm, and its two surfaces are provided with a dense PVDF layer (purity ≥99%) with a thickness of 20 μm. The dense PVDF layer is closely attached to the corresponding AgNFs multiplexed electrode to avoid poor contact caused by the electrode being embedded in the void inside the substrate.

[0041] The substrate contains spherical voids with a diameter of 10-30 μm, prepared using a biodegradable polymer microsphere template method (with polylactic acid microspheres as the template). The substrate comprises 96% PVDF by mass, 4% biodegradable polymer microsphere template by mass, and 12% spherical voids by volume. It is prepared using a low-temperature curing process (60-90℃, 2-4 hours), exhibiting a deformation ≥30%. Compared to pure PVDF substrates, it demonstrates a 3-5 times higher pressure deformation response sensitivity, accurately capturing minute pressure changes as small as 0.01 MPa.

[0042] In this application, air pressure changes (0~1.5MPa) induce elastic deformation in the substrate, leading to a linear change in its effective dielectric constant (the change in dielectric constant is directly proportional to the change in pressure, with a linear correlation coefficient R² ≥ 0.99). The capacitance of the parallel plate capacitor changes synchronously with the dielectric constant. The measurement module detects the capacitance-related S11 signal to infer the change in dielectric constant and ultimately quantifies the air pressure. Additionally, when the 20~200kHz ultrasonic signal generated by partial discharge of the device acts on the substrate, the substrate exhibits a piezoelectric effect, generating piezoelectric charges through surface polarization. These charges are collected by AgNFs multiplexed electrodes and converted into low-frequency voltage signals, thus achieving ultrasonic signal acquisition.

[0043] In some embodiments, the circuit modules are printed on a flexible polyimide (PI) substrate. The thickness of the flexible PI substrate 4 is ≤0.5mm, possessing good flexibility and high temperature resistance (temperature range). It can bend and deform along with the sensor as a whole without affecting the circuit performance.

[0044] Specifically, the circuit module includes a signal filtering unit, a signal amplification unit, a signal conditioning unit, and flexible leads. Each unit is integrated on a PI substrate and fixed to AgNFs multiplexed electrodes by flexible leads (the tensile strength of the solder joint is ≥5N) to ensure stable signal connection.

[0045] The signal filtering unit includes a low-pass filter, a band-pass filter, and a high-pass filter, employing a three-channel parallel design to achieve precise frequency band separation of the three signal types and avoid signal crosstalk. The low-pass filter is a flexible LC filter with a cutoff frequency of 500kHz, used to extract the raw ultrasonic electrical signal from 20 to 200kHz, with a filtering attenuation ≥40dB. The band-pass filter is a thin-film ceramic filter with a frequency band of 1 to 5MHz, used to extract the pressure-related raw electrical signal (S11 signal precursor), with in-band ripple. The high-pass filter is a miniature patch filter with a cutoff frequency of 300MHz, used for extraction. The original electrical signal is filtered and attenuated by ≥40dB.

[0046] The signal amplification unit includes a low-noise amplifier (LNA) and an operational amplifier, employing differentiated amplification designs for different signal characteristics. The low-noise amplifier is a flexible GaAs LNA (model ATF-54143), connected to the UHF signal channel, operating in the following frequency band. The amplifier has a voltage gain G (dB) and a noise figure ≤1.8dB, capable of amplifying weak UHF signals from the microvolt (μV) level to the millivolt (mV) level, meeting the requirements of subsequent signal processing. The operational amplifier is a miniature surface-mount OPAMP (model OPA333), connected to the ultrasonic and pressure signal channels, with an amplification factor of 100~1000 times (adjustable via an external resistor). The input offset voltage is ≤10μV, ensuring no significant distortion after amplification of low-frequency weak signals (ultrasonic and pressure signals).

[0047] The signal conditioning unit includes a wideband impedance matching network and a phase compensation circuit to optimize signal transmission characteristics. The wideband impedance matching network is an L-shaped structure composed of 1-3pF capacitors (ceramic, polyester, or PTFE capacitors) and 2-5nH inductors (wire-wound, multilayer, or thin-film inductors). According to the impedance matching formula, it matches the impedance of the AgNFs multiplexed electrode (approximately 60Ω) to the input impedance of the low-noise amplifier (50Ω), improving UHF signal transmission efficiency with a transmission loss ≤5%. The phase compensation circuit consists of miniature chip capacitors (1-2pF) and inductors (2-3nH) to correct the phase shift of the pressure S11 signal, with a phase shift correction ≤5°, ensuring accurate dielectric constant inversion.

[0048] The flexible lead is made of polyimide-coated copper wire with a diameter of 0.1mm, which has good flexibility and anti-interference performance. Each of the two AgNFs multiplexed electrodes has two shielded wires 21 leading out, which transmit high-frequency mixed signals (S11+UHF) and low-frequency signals (ultrasound) respectively. The shielding layer coverage is ≥95%, which can effectively suppress interference in high-voltage and strong electromagnetic environments, and the signal-to-noise ratio is ≥30dB.

[0049] In addition, the embodiment also provides a method for monitoring signals of high-altitude casing equipment, including the following steps:

[0050] S1, attach the sensor to the inner wall of the air chamber 14, and use the measurement module to synchronously convert the pressure change of the air chamber 14, the ultrasonic signal generated by the partial discharge of the equipment, and the UHF electromagnetic signal into the original electrical signal.

[0051] S2, through the circuit module, separates the original electrical signal according to frequency band and performs amplification, conditioning and other enhancement processes to obtain three types of conditioned and optimized signals;

[0052] S3 converts pressure-related signals into precisely quantified air pressure values ​​through calibration, modeling, temperature correction, and repeatability verification.

[0053] S4 integrates the conditioned and optimized ultrasonic signal, UHF signal and quantified pressure value synchronously, and transmits them to external monitoring equipment through flexible shielded cable 15 to achieve synchronous monitoring of the three parameters.

[0054] In some embodiments, step S1 involves inputting data from the specification document of the high-altitude casing equipment to be monitored. Specifically, this includes:

[0055] S11: Sensors are deployed in close alignment

[0056] During deployment, the gas recovery device is activated to reduce the pressure inside the gas chamber to [a certain value]. (Preferred pressure: 0.05MPa) Close the main valve of the gas chamber to prevent outside air from entering the polluted gas; slowly open the reserved interface valve, connect the dedicated transition sealing joint, and seal it with a threaded connection and sealing ring to ensure no leakage during soap liquid detection; bend and fold the sensor to a diameter of 7mm, and slowly insert it into the gas chamber through the insertion channel of the transition joint, using the observation camera inside the gas chamber (miniature high-definition camera, diameter ≤6mm) to observe the position in real time; adjust the sensor's attitude using a flexible telescopic rod (length 1.5m, diameter 6mm) so that the sensing surface faces the gas chamber. For the smooth inner wall area (free from protrusions and oil stains), slowly press the sensor surface to ensure the flexible silicone adhesive layer adheres tightly to the inner wall. Continue pressing for 8-12 minutes (preferably 10 minutes) to achieve initial fixation. Maintain a slight positive pressure of 0.05 MPa within the air chamber and allow it to stand until the silicone adhesive is completely cured. After the sensor measuring end is fixed, the adhesion to the inner wall of the air chamber is ≥98%, establishing direct coupling between the measuring module and the air chamber environment, eliminating signal distortion caused by installation gaps, with a pressure transmission error ≤±0.5%, and UHF signal coupling efficiency improved to ≥85%.

[0057] S12: Reusable electrode-substrate collaborative acquisition

[0058] During the data acquisition process, the pressure change (0~1.5MPa) in air chamber 14 was measured. This pressure change caused elastic deformation in the porous PVDF substrate 2 (the deformation was proportional to the pressure). The effective dielectric constant of the substrate changed linearly, which in turn caused a change in the capacitance value of the parallel plate capacitor composed of AgNFs multiplexed electrodes (the change in capacitance was...). Where ε0 is the vacuum permittivity and S is the plate area. (where d is the change in dielectric constant and d is the distance between the electrodes), generating a pressure-related raw electrical signal (amplitude 10~100μV). Generally, the vacuum dielectric constant is a fixed value. The electrode spacing is equal to the PVDF substrate thickness (300 μm).

[0059] Acquire the partial discharge ultrasonic signal (20~200kHz, amplitude 1~10μV) from the device. The 20~200kHz ultrasonic signal generated by the partial discharge of the device acts on the substrate, triggering the piezoelectric effect. The substrate surface is polarized, generating piezoelectric charges (charge amount) Where d33 is the piezoelectric coefficient, and is the piezoelectric coefficient of conventional flexible PVDF. (where F is ultrasonic pressure), the charge is collected by the AgNFs multiplexed electrode and converted into the original ultrasonic electrical signal (amplitude 1~10μV).

[0060] UHF electromagnetic signals (300MHz~3GHz, amplitude 0.1~1μV) are acquired and received by the peripheral broadband antenna region (dipole antenna) of the AgNFs multiplexing electrode, and converted into raw UHF electrical signals (amplitude 0.1~1μV).

[0061] In some embodiments, step S2 involves using the filtering, amplification, and conditioning units of the circuit module to perform frequency band separation, weak signal amplification, and transmission characteristic optimization on the mixed original electrical signal, resulting in three types of conditioned and optimized signals. This solves the problems of signal crosstalk and the inability to detect weak signals in the prior art. Specifically, step S2 includes:

[0062] S21: Separate signal frequency band

[0063] During signal separation, the signal filtering unit of the mixed raw electrical signal input circuit module filters signals according to preset frequency bands, with the criterion being whether the signal frequency is within the target frequency band. A low-pass filter (cutoff frequency 500kHz) filters out the 20~200kHz ultrasonic raw electrical signal, removing high-frequency interference (≥500kHz). A band-pass filter (frequency band 1~5MHz) filters out the 1~5MHz pressure-related raw electrical signal (S11 signal precursor), removing low-frequency (≤1MHz) and high-frequency (≥5MHz) interference. A high-pass filter (cutoff frequency 300MHz) filters out the 300MHz~3GHz UHF raw electrical signal, removing low-frequency interference (≤300MHz). The filtering unit uses parallel processing with no time delay. The resulting frequency-band raw electrical signals (ultrasonic, pressure, and UHF) provide a clean input for signal amplification, effectively avoiding crosstalk between different frequency bands, and achieving a signal purity ≥95% after filtering.

[0064] S22: Amplify weak signals

[0065] During signal amplification, a differentiated amplification strategy is employed, selecting amplification devices based on the signal frequency band and amplitude characteristics. The original UHF electrical signal is input to a low-noise amplifier (flexible GaAs LNA), and the amplifier voltage gain G (dB) is calculated using the logic that output amplitude = input amplitude. (Gain / 20) (Example: Input 0.5μV, gain 28dB, output amplitude) The raw ultrasonic and pressure electrical signals are input into an operational amplifier (miniature patch OPAMP) with a magnification of 100-1000 times (preferably 500 times). The calculation logic is: Output amplitude = Input amplitude × Amplification factor (e.g., ultrasonic input 5μV, amplified 500 times, output amplitude...). During the amplification process, the signal amplitude is monitored in real time to ensure it does not exceed the device's saturation threshold. The resulting amplified frequency-band signal meets the signal strength requirements for subsequent pressure quantization and monitoring. The technical effect is to make weak signals detectable, with an amplification distortion rate ≤1%. For example, the amplified ultrasonic signal amplitude is 0.1~10V, the amplified pressure signal amplitude is 100mV / 10V, and the amplified UHF signal amplitude is 3~30mV.

[0066] S23: Conditioning and optimizing amplified signal

[0067] Specifically, the amplified UHF signal is input into a broadband impedance matching network (L-shaped structure, 2pF capacitor + 3nH inductor). According to the impedance matching formula, the capacitor and inductor values ​​are fine-tuned to Zin = 50Ω to achieve impedance matching. The amplified pressure signal is then input into a phase compensation circuit (1pF capacitor + 2nH inductor). Through phase detection and correction algorithms, the phase offset is corrected to ≤5°. For ultrasonic signal conditioning, no additional conditioning is required; the signal is directly output (because the ultrasonic signal has a single frequency band, the amplified quality meets the requirements).

[0068] Specifically, the conditioned and optimized ultrasonic signal (20~200kHz, amplitude 0.1~10V), the conditioned and optimized pressure signal (1~5MHz, amplitude 1~50V), and the conditioned and optimized UHF signal (300MHz~3GHz, amplitude 3~30mV) provide high-quality signals for pressure quantification and final monitoring. The technical effect is a signal-to-noise ratio ≥30dB and a transmission loss ≤5%, laying the foundation for subsequent accurate quantification.

[0069] In some embodiments, step S3 is provided to convert the pressure-related S11 signal into a precisely quantified air pressure value through calibration, linear modeling, temperature correction, and repeatability verification, thereby solving the problems of low pressure measurement accuracy and large temperature influence in the prior art.

[0070] S31: Calibration pressure-dielectric constant

[0071] During calibration, the sensor is placed in a pressure calibration chamber, with the temperature controlled at 25℃ (room temperature) and humidity ≤60%. Known pressure is applied step-by-step using a standard pressure source, and each pressure point is held stable for at least 5 seconds (the criterion is pressure fluctuation). The relative permittivity εr of the porous PVDF substrate 2 was collected using an impedance analyzer at each pressure point, and the measurement was repeated 3-5 times (preferably 4 times). The average value of the permittivity measurement at each pressure point was taken to reduce random errors. Finally, a pressure-permittivity correspondence dataset was obtained (e.g., 0 MPa corresponds to εr=2.05, 0.2 MPa corresponds to εr=2.23, 0.4 MPa corresponds to εr=2.41, ..., 1.5 MPa corresponds to εr=3.48), which provides basic data for linear modeling, obtains accurate correspondences of physical quantities, and has a data dispersion ≤ ±0.005.

[0072] S32: Establish a linear model

[0073] Specifically, tensile mechanical tests were conducted on the porous PVDF substrate 2 using a tensile testing machine to obtain the linear relationship between the pressure P and the substrate deformation ε, and the results were obtained through fitting. (k1 is the pressure-deformation coefficient, k0 is the initial pressure offset, as tested) The dielectric constant of the substrate under different deformations was tested using an impedance analyzer to obtain the linear relationship between the deformation ε and the relative dielectric constant εr. The fitted result was εr = k2ε + k3 (where k2 is the deformation-dielectric constant coefficient and k3 is the initial dielectric constant offset, as determined by testing). (k3=2.05); Solving the two equations simultaneously and eliminating the deformation ε, we get ,in The final linear model is The fitting process uses the least squares method, and the linear correlation coefficient is... .

[0074] In one embodiment, a pressure quantification linear model Its purpose is to achieve direct conversion of dielectric constant to pressure, and the technical effect is that the conversion error is ≤±2%, which meets the accuracy requirements of power equipment monitoring.

[0075] S33: Temperature Correction Compensation

[0076] Specifically, at each temperature point, three fixed pressures of 0.3 MPa, 0.7 MPa, and 1.0 MPa were applied, and the corresponding relative permittivity εr was recorded. The variation of the permittivity with temperature was analyzed, and a temperature coefficient α was obtained by fitting (α is the rate of change of the permittivity with temperature, ranging from 0.001 to 0.003, and α = 0.002 after testing). A temperature compensation term P_compensation = α × (T - 25) was added (T is the actual measured temperature, and 25℃ is the calibration reference temperature). The corrected pressure value P_correction = P_calculated + P_compensation (P_calculated is the value calculated by the linear model). For example, at 65℃, the linear model calculates the pressure P_calculated = 0.7 MPa, and the temperature compensation term P_compensation... Corrected pressure P .

[0077] In one embodiment, the temperature-corrected pressure quantization model P is corrected. This technology improves the accuracy of pressure measurement under different temperature conditions. The technical effect is that the temperature influence error is ≤±1%, and the total measurement error is ≤±2% in the range of 25~120℃.

[0078] S34: Repeatability Calibration Verification

[0079] The relative permittivity εr under cyclic pressure (cyclic pressure range 0~1.5MPa) can be used to verify the repeatability and stability of the quantization model and ensure reliable long-term operation.

[0080] At a normal temperature of 25℃, a cyclic pressure of 0~1.5MPa was applied 1000 times through a pressure calibration chamber. Each cycle included pressurization (rate 0.1MPa / s), holding pressure (5s), and depressurization (rate 0.1MPa / s). The relative permittivity εr corresponding to the 0.5MPa pressure point in each cycle was recorded. The average permittivity εr_avg and standard deviation σ of the 1000 cycles were calculated. The repeatability error was calculated as σ / εr_avg × 100%, with a repeatability error ≤ ±1.5%, resulting in a precisely quantified air pressure value. For example, the corrected pressure value was 0.68MPa, providing accurate pressure data for final monitoring. The technical effect was that the pressure measurement accuracy reached within ±2%, and the repeatability error was ≤ ±1.2%, meeting the long-term monitoring needs of high-altitude casing equipment.

[0081] In step S4 provided in some embodiments, the conditioned and optimized ultrasonic signal, UHF signal, and quantified pressure value are synchronously integrated and transmitted to an external monitoring device to achieve collaborative monitoring of "insulation defects-gas characteristics," solving the problems of data asynchrony and high transmission leakage risk in the prior art. Specifically, step S4 includes:

[0082] S41: Synchronization Alignment Signal

[0083] The synchronous triggering unit (flexible high-speed trigger chip, model AD9516) of the flexible integrated circuit module adds a unified timestamp (timestamp accuracy ≤1μs) to the conditioned and optimized ultrasonic signal, UHF signal, and quantized pressure value, aligning the data along the time axis. The judgment condition is that the time difference of the three types of data is ≤1ms. For example, the amplitude of the ultrasonic signal at t=10.000ms is 2.5V, the amplitude of the UHF signal at t=10.000ms is 20mV, and the quantized pressure value at t=10.000ms is 0.68MPa. After synchronization, a time-aligned three-parameter data set is formed.

[0084] The system obtains three-parameter data with time synchronization, in the format of timestamp + ultrasonic signal amplitude + UHF signal amplitude + quantized pressure value, which can avoid misjudgment of faults caused by time difference and improve the accuracy of collaborative analysis to ≥95%.

[0085] S42: Integrate transmission data

[0086] The synchronized three-parameter data will be formatted according to the preset format "timestamp ( The data is integrated as follows: (1) + (2) ultrasonic signal amplitude (V) + (3) UHF signal amplitude (mV) + (4) quantified pressure value (MPa), for example... The integrated data is transmitted via a polyimide-coated flexible shielded cable 15, which exits through the sealed terminals of a transition joint. The entire cable is un-perforated, with a sealing gap ≤0.01mm. During transmission, a gas leak detector monitors the data in real time, with the leak rate of the gas chamber as the determining factor. The obtained synchronous monitoring data (transmission rate ≥1Mbps) can be used by external monitoring equipment to assess the status of high-altitude bushing equipment. The technical effect is to achieve synchronous monitoring of "insulation defects-gas characteristics", with stable data transmission without loss (packet loss rate ≤0.1%), and the gas chamber sealing performance meets the operating requirements of power equipment.

[0087] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A sensor for monitoring signals of high-altitude casing equipment, characterized in that, include: The shell is made of flexible material and forms an accommodating space. The outer side of the shell is coated with a flexible silicone adhesive layer to achieve a gapless fit to the inner wall of the air chamber of the high-altitude casing equipment. The measurement module, located within the enclosure, is used to simultaneously acquire ultrasonic signals, barometric pressure signals, and UHF electromagnetic signals. The circuit module, located within the housing space and connected to the electrode signals of the measurement module, is used to separate, amplify, and condition ultrasonic signals, barometric pressure signals, and UHF electromagnetic signals.

2. The sensor according to claim 1, characterized in that, The shell is composed of a corrosion-resistant outer layer, an elastic middle layer, and a reinforced inner layer that are tightly bonded together from the outside to the inside. The whole shell has flexible characteristics to adapt to the curved structure of the inner wall of the air chamber.

3. The sensor according to claim 1, characterized in that, The measurement module includes two symmetrically arranged AgNFs multiplexed electrodes and a porous PVDF substrate sandwiched between them. The AgNFs multiplexed electrodes and the porous PVDF substrate are tightly bonded together with a high-temperature resistant adhesive without air gaps. The AgNFs multiplexed electrodes and the porous PVDF substrate work together to achieve synchronous sensing and electrical signal conversion of three types of signals: ultrasonic, pressure, and UHF electromagnetic signals.

4. The sensor according to claim 3, characterized in that, Two AgNFs multiplexed electrodes can work together to form a dipole antenna to receive UHF electromagnetic signals, while also serving as parallel plate capacitor plates and piezoelectric charge collection electrodes, thus achieving triple-function multiplexing.

5. The sensor according to claim 3, characterized in that, The porous PVDF substrate is a flexible and deformable structure with a porous internal structure. It can deform and change its dielectric constant by changing the air pressure. At the same time, it can receive ultrasonic signals through the piezoelectric effect, realizing dual sensing of pressure and ultrasonic signals.

6. The sensor according to claim 1, characterized in that, The circuit module is printed on a flexible substrate and integrated with the measurement module. It includes a signal filtering unit, a signal amplification unit, a signal conditioning unit, and flexible leads. It can separate three types of mixed signals according to frequency bands and perform conditioning operations such as amplification, impedance matching, and phase compensation on the separated signals. The flexible leads can avoid crosstalk between signals of different frequency bands.

7. The sensor according to claim 1, characterized in that, The flexible silicone adhesive layer on the outside of the housing has a preset peel strength after curing, ensuring that the sensor adheres firmly to the inner wall of the gas chamber.

8. The sensor according to claim 1, characterized in that, The sensor has a flexible structure that can be bent and folded. It can be inserted into the air chamber through the original reserved interface of the high-altitude casing equipment. After attitude adjustment, it can achieve a gapless fit with the inner wall of the air chamber through a flexible silicone adhesive layer.

9. A method for monitoring signals of high-altitude casing equipment, characterized in that, Includes the following steps: S1, attach the sensor of any one of claims 1-8 to the inner wall of the gas chamber, and use the measurement module to synchronously convert the pressure change of the gas chamber, the ultrasonic signal generated by the partial discharge of the device, and the UHF electromagnetic signal into the original electrical signal. S2, through the circuit module, separates the original electrical signal according to frequency band and performs amplification, conditioning and other enhancement processes to obtain three types of conditioned and optimized signals; S3 converts pressure-related signals into precisely quantified air pressure values ​​through calibration, modeling, temperature correction, and repeatability verification. S4 integrates the conditioned and optimized ultrasonic signal, UHF signal and quantified pressure value synchronously, and transmits them to external monitoring equipment through a flexible shielded cable to achieve synchronous monitoring of the three parameters.

10. The monitoring method according to claim 9, characterized in that, In step S1, the sensor achieves the conversion of physical quantities into electrical signals of pressure, ultrasound, and UHF electromagnetic signals through the synergistic effect of the multiplexed electrode and the porous PVDF substrate, utilizing the change in dielectric constant of substrate deformation, the piezoelectric effect of the substrate, and the antenna receiving function of the electrode, respectively. In step S4, the time axis alignment of multiple parameter signals is achieved through the synchronous triggering unit, and the integrated data is transmitted in a preset format to ensure the synchronization and stability of data transmission and the sealing performance of the air chamber.

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