A dual ultrasonic partial discharge sensor with a shielding structure and a partial discharge sensor terminal

Abstract

This application relates to the field of power equipment monitoring technology, and particularly to a dual ultrasonic partial discharge sensor and a partial discharge sensor terminal with a shielded structure. The dual ultrasonic partial discharge sensor includes a first digital probe and a second digital probe, which are symmetrically distributed inside a first housing. The receiving end of the first digital probe is located on one side of the first housing and is used to attach to the device under test to receive ultrasonic signals emitted from inside the device. The receiving end of the second digital probe is located on the other side of the first housing and is used to receive ultrasonic signals from the external environment of the device under test. The shielding structure includes at least one shielding slot for accommodating a sound-insulating medium to attenuate the ultrasonic signals propagating between the first and second digital probes. This design enables reliable acquisition of wideband ultrasonic signals and effectively suppresses crosstalk between the two probes, significantly improving the accuracy and anti-interference capability of partial discharge monitoring.

Description

Technical Field

[0001] This application relates to the field of power equipment monitoring technology, and in particular to a dual ultrasonic partial discharge sensor with a shielding structure and a partial discharge sensor terminal. Background Technology

[0002] Partial discharge (PD) refers to a non-penetrating discharge phenomenon that occurs inside or on the surface of the insulation of power equipment. It is an important characteristic signal reflecting the deterioration of the insulation of power equipment. By monitoring PD signals online, early insulation defects of equipment can be detected in time, thus avoiding serious failures.

[0003] Existing technologies generally use analog microphone-type ultrasonic sensors for partial discharge monitoring. By attaching the analog microphone-type partial discharge sensor to the power equipment, the analog microphone can capture the ultrasonic signals emitted by the power equipment, thereby determining the insulation status of the equipment.

[0004] However, analog microphone-type ultrasonic sensors have the following problems: First, the acquisition frequency band is narrow, and the low noise characteristics of analog microphones cannot meet the acquisition requirements of wide frequency band (especially low frequency band) signals; second, analog signals are easily affected by cable length and manufacturing process, have poor anti-interference ability, and data reliability is difficult to guarantee. Summary of the Invention

[0005] This application provides a dual ultrasonic partial discharge sensor with a shielding structure and a partial discharge sensor terminal to solve the problem that traditional sensors cannot meet the requirements for partial discharge monitoring.

[0006] In a first aspect, embodiments of this application provide a dual ultrasonic partial discharge sensor with a shielding structure, comprising: a first housing; a first digital probe and a second digital probe, the first and second digital probes being symmetrically distributed inside the first housing, the receiving end of the first digital probe being located on one side end face of the first housing, the first digital probe being used to fit against the device under test to receive ultrasonic signals emitted from inside the device under test; the receiving end of the second digital probe being located on the other side end face of the first housing, being used to receive ultrasonic signals from the external environment of the device under test; the outer surface of the first housing near the second digital probe being a frosted reflective surface, the frosted reflective surface being used to increase the reflection of ultrasonic signals from the external environment by the first housing; and a shielding structure, the shielding structure being located between the first digital probe and the second digital probe, the shielding structure including at least one shielding slot, the shielding slot being used to accommodate a sound-insulating medium to attenuate the ultrasonic signals propagating between the first digital probe and the second digital probe.

[0007] In one possible implementation, the first digital probe includes: a first body; a first acoustic cavity; the first acoustic cavity includes a first inlet end, a first cavity body, and a first outlet end, the first inlet end being located on one side surface of the first body, the first outlet end being located on the other side surface of the first body, the first cavity body gradually tightening from the first inlet end to the first outlet end to form a conical structure; a first dustproof mesh covering the first inlet end to form a receiving end of the first digital probe; a first digital microphone circuit board embedded on the side of the first body away from the first dustproof mesh; the first digital microphone circuit board having a first through hole positioned directly opposite the first outlet end; a first digital microphone located on the side of the first through hole away from the first outlet end and directly opposite the first outlet end; and the first digital microphone being electrically connected to the first digital microphone circuit board. The circuit board is electrically connected; the second digital probe includes: a second body; a second acoustic cavity; the second acoustic cavity includes a second inlet end, a second cavity body, and a second outlet end, the second inlet end is opened on one side surface of the second body, the second outlet end is opened on the other side surface of the second body, the second cavity body gradually tightens from the second inlet end to the second outlet end to form a conical structure; a second dustproof net, the second dustproof net covers the second inlet end to form the sound receiving end of the second digital probe; a second digital microphone circuit board, the second digital microphone circuit board is embedded on the side of the second body away from the second dustproof net; the second digital microphone circuit board has a second through hole, the opening position of the second through hole is directly opposite the second outlet end; a second digital microphone, the second digital microphone is located on the side of the second through hole away from the second outlet end and directly opposite the second outlet end, and the second digital microphone is electrically connected to the second digital microphone circuit board.

[0008] In one possible implementation, a filler material is filled between the first body and the shielding slot, and a filler material, namely resin or rubber, is filled between the second body and the shielding slot.

[0009] In one possible implementation, the shielding slot is an accommodating space formed by a first housing and parallel-distributed first and second pressure plates; a filler is filled between the first pressure plate and the first body, and a filler is filled between the second pressure plate and the second body; a plurality of first pillars are provided on the side of the first pressure plate near the first body, and the plurality of first pillars extend into the interior of the first body so that the first through hole and the first outlet end are tightly fitted; a plurality of second pillars are provided on the side of the second pressure plate near the second body, and the plurality of second pillars extend into the interior of the second body so that the second through hole and the second outlet end are tightly fitted.

[0010] In one possible implementation, at least one intermediate partition is provided between the first pressure plate and the second pressure plate, and the intermediate partition is parallel to the first pressure plate and the second pressure plate to form a plurality of shielding slots.

[0011] In one possible implementation, a first sealing gasket is provided between the first body and the first digital microphone circuit board, and a second sealing gasket is provided between the second body and the second digital microphone circuit board.

[0012] In one possible implementation, the sound insulation medium has a multi-layered structure, with an outer sound insulation layer and an inner absorption layer. The sound insulation layer is made of glass wool, polyester fiber wool, polyurethane sound-absorbing wool, rock wool, or butyl rubber. The absorption layer has a gradient pore size porous structure, an open-pore interconnected porous structure, or a honeycomb porous composite structure. The pores of the absorption layer are filled with sealant. The gradient pore size porous structure has at least two levels of pore size layers arranged sequentially from the outside to the inside, and the pore size of each level of pore size layer decreases gradually. The open-pore interconnected porous structure has interconnected three-dimensional mesh pores. The honeycomb porous composite structure has hexagonal honeycomb pores.

[0013] In one possible implementation, the material of the sound insulation layer is matched to the frequency band of the ultrasonic signal to be attenuated; when there are multiple shielding slots, different shielding slots are used to accommodate the same or different sound insulation media, where different sound insulation media refer to different sound insulation layer materials and / or different absorption layer structures.

[0014] In one possible implementation, a third sealing gasket is provided on the outer surface of the first housing near the first digital probe.

[0015] Secondly, embodiments of this application also provide a partial discharge sensor terminal, which includes at least the dual ultrasonic partial discharge sensor with a shielding structure described in the first aspect and its various implementations.

[0016] As described above, this application provides a dual ultrasonic partial discharge sensor and a partial discharge sensor terminal with a shielding structure. The dual ultrasonic partial discharge sensor with a shielding structure may include a first housing; a first digital probe and a second digital probe, symmetrically distributed inside the first housing. The receiving end of the first digital probe is located on one side of the first housing and is used to attach to the device under test (DUT) to receive ultrasonic signals emitted from inside the DUT; the receiving end of the second digital probe is located on the other side of the first housing and is used to receive ultrasonic signals from the external environment of the DUT; the outer surface of the first housing near the second digital probe is a frosted reflective surface, used to increase the reflection of ultrasonic signals from the external environment by the first housing; and a shielding structure located between the first and second digital probes. The shielding structure includes at least one shielding slot for accommodating a sound-insulating medium to attenuate the ultrasonic signals propagating between the first and second digital probes. This achieves reliable acquisition of wideband ultrasonic signals and effectively suppresses crosstalk between the two probes, significantly improving the accuracy and anti-interference capability of partial discharge monitoring. Attached Figure Description

[0017] Figure 1 This is a first cross-sectional view of a dual ultrasonic partial discharge sensor with a shielding structure provided in an embodiment of this application. Figure 2 A second cross-sectional view of a dual ultrasonic partial discharge sensor with a shielding structure provided in an embodiment of this application; Figure 3 A schematic diagram illustrating the application of the dual ultrasonic partial discharge sensor with a shielding structure provided in this embodiment of the application. Figure 4 A cross-sectional view of the second digital probe provided in an embodiment of this application; Figure 5 A third cross-sectional view of a dual ultrasonic partial discharge sensor with a shielding structure provided in an embodiment of this application; Figure 6 A fourth cross-sectional view of a dual ultrasonic partial discharge sensor with a shielding structure provided in an embodiment of this application; Figure 7 A schematic diagram of an absorption layer provided in an embodiment of this application; Figure 8 The waveform diagram collected when there is no shielding structure provided in the embodiments of this application; Figure 9 Waveforms collected when a shielded structure is provided in the embodiments of this application; Figure 10 This is a signal strength comparison diagram provided for an embodiment of this application; Figure 11This is a schematic diagram of the partial discharge sensor terminal provided in an embodiment of this application.

[0018] Wherein, 100-first housing; 101-slot; 102-first through hole; 200-first digital probe; 201-first body; 2021-first inlet end; 2022-first cavity; 2023-first outlet end; 202-first acoustic cavity; 203-first dustproof mesh; 204-first digital microphone circuit board; 2041-first through hole; 205-first digital microphone; 300-second digital probe; 301-second body; 3021-second inlet end; 3022-second cavity; 3023-second outlet end; 302-second acoustic cavity ; 303-Second dustproof mesh; 304-Second digital microphone circuit board; 3041-Second via; 305-Second digital microphone; 306-Second sealing gasket; 400-Shielding structure; 401-Shielding slot; 402-Sound insulation medium; 4021-Sound insulation layer; 4022-Absorption layer; 4023-Sealant; 403-First pressure plate; 4031-First column; 404-Second pressure plate; 4041-Second column; 405-Intermediate partition; 500-Dual ultrasonic partial discharge sensor with shielding structure; 600-Second housing; 700-Buffer pad. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of this application.

[0020] First, the terminology used in the embodiments of this application will be introduced by way of example.

[0021] ① Substation: refers to power facilities used for voltage transformation, power distribution, fault protection and grid dispatch. It is equipped with high-voltage electrical equipment such as transformers, circuit breakers, switchgear, disconnecting switches, instrument transformers, and surge arresters. It is the core node for the safe and stable operation of the power system.

[0022] ②Partial discharge refers to the localized, non-penetrating, weak discharge phenomenon that occurs when the insulation structure of high-voltage electrical equipment is subjected to operating voltage, due to the presence of bubbles, cracks, impurities, or aging defects, resulting in a concentrated electric field.

[0023] This phenomenon is a typical early sign of equipment insulation degradation and can be detected online using sensors such as ultra-high frequency, transient ground voltage, and ultrasonic sensors. It is an important basis for judging the health status of equipment.

[0024] To address the issue that existing analog microphone-type ultrasonic sensors cannot meet the requirements for partial discharge monitoring, this application provides a dual ultrasonic partial discharge sensor with a shielding structure and a partial discharge sensor terminal.

[0025] Figure 1 This is a first cross-sectional view of a dual ultrasonic partial discharge sensor with a shielding structure provided in an embodiment of this application.

[0026] Figure 2 This is a second cross-sectional view of a dual ultrasonic partial discharge sensor with a shielding structure provided in an embodiment of this application.

[0027] like Figure 1 and Figure 2 As shown, this application embodiment provides a dual ultrasonic partial discharge sensor with a shielding structure. The dual ultrasonic partial discharge sensor may include a first housing 100, a first digital probe (full name may be a first digital microphone probe) 200 and a second digital probe (full name may be a second digital microphone probe) 300.

[0028] To facilitate the explanation of the positional relationships between the various structures of the dual ultrasonic partial discharge sensor, a three-dimensional coordinate system is established. The x-axis represents the length of the first housing 100, parallel to the receiving directions of the first digital probe 200 and the second digital probe 300; the y-axis represents the width of the first housing 100; and the z-axis represents the height of the first housing 100, perpendicular to the plane formed by the x-axis and y-axis.

[0029] In this embodiment, the first housing 100 may be rectangular in shape and made of engineering plastics, such as acrylonitrile-butadiene-styrene copolymer (ABS) or polycarbonate. This embodiment does not specifically limit the material.

[0030] The first digital probe 200 and the second digital probe 300 are located inside the first housing 100. Specifically, the first digital probe 200 and the second digital probe 300 can be symmetrically distributed along the length of the first housing 100. The receiving end of the first digital probe 200 is located on one side of the first housing 100, and the receiving end of the second digital probe 300 is located on the other side of the first housing 100.

[0031] It is worth noting that both the first digital probe 200 and the second digital probe 300 can be probes based on digital microphones. Furthermore, the orientation of the first digital probe 200 is opposite to that of the second digital probe 300. Specifically, the first digital probe 200 can face the device under test, while the second digital probe 300 can face outwards from the device under test. The device under test may be, for example, a switch cabinet or a gas-insulated metal-enclosed switchgear.

[0032] Figure 3 This is a schematic diagram illustrating the application of the dual ultrasonic partial discharge sensor with a shielding structure provided in an embodiment of this application.

[0033] like Figure 3 As shown, when the device under test is a switch cabinet, the first digital probe 200 faces inward to receive the partial discharge signal inside the cabinet, and the second digital probe 300 faces outward to receive the interference signal outside the cabinet.

[0034] Understandably, the first digital probe 200 is used to attach to the device under test (DUT) to receive ultrasonic signals emitted from within the DUT. In practical applications, when partial discharge occurs inside the DUT, the discharge point releases energy instantaneously, causing the surrounding medium to expand in volume, thereby generating ultrasonic signals (or partial discharge ultrasonic signals, or simply ultrasonic signals). These partial discharge ultrasonic signals can be captured by the first digital probe 200 for subsequent partial discharge analysis.

[0035] Additionally, the second digital probe 300 faces outwards from the device under test and is used to receive ultrasonic signals (or interference ultrasonic signals, ultrasonic signals) from the external environment of the device under test. In practical applications, these ultrasonic signals are generally composed of various sound sources in the external environment, such as partial discharge ultrasonic waves generated by adjacent switch cabinets or cable terminals, mechanical vibrations during the operation of power equipment (such as magnetostriction of transformer cores, fan operation), environmental airflow disturbances, noise generated by people walking or tools colliding, and occasional ultrasonic frequency components from natural meteorological phenomena such as wind and rain.

[0036] It is understood that the embodiments of this application can collect partial discharge signals inside the cabinet and interference signals outside the cabinet. Then, the two signals can be compared, denoised, and differentially processed to effectively eliminate environmental interference, accurately extract the true partial discharge characteristics, and finally determine whether the device under test has partial discharge.

[0037] See also Figure 1 and Figure 2 The dual ultrasonic partial discharge sensor provided in this application embodiment also includes a shielding structure 400, which is located between the first digital probe 200 and the second digital probe 300. The shielding structure 400 includes at least one shielding slot 401, which is used to accommodate a sound-insulating medium 402 to attenuate the ultrasonic signal propagating between the first digital probe 200 and the second digital probe 300.

[0038] It is understandable that the ultrasonic signal propagating between the first digital probe 200 and the second digital probe 300 is a non-target crosstalk signal. That is, it should not be used by the first digital probe 200 to collect partial discharge ultrasonic signals (because the signal does not come from the partial discharge inside the device under test), nor should it be used by the second digital probe 300 to collect environmental interference ultrasonic signals (because the signal does not come from the external environment). This phenomenon, in which the signal is accidentally propagated from one probe through the solid conduction of the first housing 100 or the internal air path to another probe, causing the detection results to be distorted, is crosstalk between probes.

[0039] The shielding structure 400 provided in this application embodiment can be arranged between the first digital probe 200 and the second digital probe 300. Through the sound insulation medium 402 in its shielding slot 401, the non-target crosstalk signal transmitted through the solid conduction of the first housing 100 or the internal air is reflected, scattered and absorbed multiple times, so that the crosstalk signal is greatly attenuated before reaching the other probe, thereby effectively suppressing the mutual interference between the two probes and improving the detection accuracy.

[0040] In this embodiment, the insertion direction of the shielding slot 401 can be the z-axis direction. The first housing 100 can be a separable structure (e.g., separable along the z-axis direction), for example, including an upper housing and a lower housing, or including a main housing and an end cap. In this embodiment, after the sound insulation medium 402 is inserted into the shielding slot 401, the first housing 100 can be assembled and closed using screws or the like to form a complete sensor housing. This ensures the stable installation of the sound insulation medium 402 and reduces the assembly difficulty.

[0041] In some implementations, in order to improve the noise reduction effect of the sound insulation medium 402, the cross-sectional shape of the shielding slot 401 can be set to a square to obtain a larger filling volume at the same slot depth, so as to accommodate a larger volume of sound insulation medium 402 and thus improve the noise reduction effect.

[0042] It should also be noted that, in this embodiment of the application, the propagation pattern of the interfering ultrasound signal (such as fixed time delay, strong amplitude correlation in a specific frequency band, etc.) can be identified by analyzing the time correlation, frequency distribution, and amplitude ratio between the signals acquired by the first digital probe 200 and the signals acquired by the second digital probe 300. Then, by using adaptive filtering, blind source separation, or differential cancellation algorithms, the crosstalk component can be dynamically filtered out from the signals acquired by the first digital probe 200, thereby further solving the problem of crosstalk between the two probes.

[0043] It should also be noted that the first digital probe 200 and the second digital probe 300 in this application embodiment are both implemented using digital microphones, which can achieve high-sensitivity acquisition of wide-band, especially low-band (e.g., 20kHz-100kHz) ultrasonic signals. Their low-frequency response can be extended to 20kHz or even lower, thereby making up for the defects of traditional analog microphones, which have poor low-frequency response and cannot effectively capture low-frequency ultrasonic components of partial discharge due to their own physical structure limitations.

[0044] As can be seen from the above, this application provides a dual ultrasonic partial discharge sensor with a shielding structure. The dual ultrasonic partial discharge sensor may include a first housing 100; a first digital probe 200 and a second digital probe 300, which are symmetrically distributed inside the first housing 100. The receiving end of the first digital probe 200 is located on one side of the first housing 100, and the first digital probe 200 is used to attach to the device under test to receive ultrasonic signals emitted from inside the device under test. The receiving end of the second digital probe 300 is located on the other side of the first housing 100. The side end face is used to receive ultrasonic signals from the external environment of the device under test. The outer surface of the first housing 100 near the second digital probe 300 is a frosted reflective surface, which increases the reflection of ultrasonic signals from the external environment by the first housing 100. A shielding structure 400 is located between the first digital probe 200 and the second digital probe 300. The shielding structure 400 includes at least one shielding slot 401, which is used to accommodate a sound-insulating medium 402 to attenuate the ultrasonic signals propagating between the first digital probe 200 and the second digital probe 300. In this way, reliable acquisition of broadband ultrasonic signals can be achieved, and crosstalk between the two probes can be effectively suppressed, significantly improving the accuracy and anti-interference capability of partial discharge monitoring.

[0045] See also Figure 1 and Figure 2 The first digital probe 200 includes a first body 201 and a first acoustic cavity 202. The first acoustic cavity 202 is formed in the first body 201 and is used to converge and guide ultrasonic signals. The first body 201 can be made of engineering plastic, such as ABS injection molding.

[0046] Furthermore, the first acoustic cavity 202 includes a first inlet end 2021, a first cavity body 2022, and a first outlet end 2023. The first inlet end 2021 can be circular or elliptical in shape and is located on one side surface of the first body 201. The first outlet end 2023 can be circular and is located on the other side surface of the first body 201. The first cavity body 2022 gradually narrows from the first inlet end 2021 to the first outlet end 2023 to form a conical structure. It can be understood that through the conical structure of the first acoustic cavity 202, the ultrasonic waves entering from the first inlet end 2021 can be concentrated to the first outlet end 2023, thereby improving the receiving sensitivity and signal-to-noise ratio of the first digital microphone 205 for ultrasonic signals.

[0047] It is worth noting that the full cone angle of the first cavity 2022 provided in this embodiment can be ≥10°. Furthermore, in actual low-frequency ultrasound scenarios, the cone angle can be maximized to ensure sufficient sound energy convergence.

[0048] For example, the dimensions and taper of the first cavity 2022 are calculated as follows: the diameter of the large end (the first inlet end 2021) D = 14.32 mm, the diameter of the small end (the first outlet end 2023) d = 1.82 mm, and the center distance (i.e., the vertical distance from the first inlet end 2021 to the first outlet end 2023, which can also be called the acoustic cavity length) is 50 mm. Then, the taper of the first cavity 2022 is C = (14.32 - 1.82) / 50 = 0.25.

[0049] Furthermore, the semi-cone angle a / 2 of the first cavity 2022 is approximately 7.13° (arctan(0.125)) and the full cone angle is approximately 14.26°, which meets the requirements.

[0050] Further details can be found by referring to [link / reference]. Figure 1 and Figure 2 The first digital probe 200 may also include a first dustproof mesh 203, which covers the first inlet end 2021 to form the receiving end of the first digital probe 200. It should be noted that, in a specific implementation, the first housing 100 may have a first through hole 102, which corresponds to the position of the first dustproof mesh 203, so as to expose the receiving end of the first digital probe 200 to the outside.

[0051] In practical applications, the first dustproof net 203 can be 80 mesh, and the specific size can be adjusted according to actual needs. This application embodiment does not make specific limitations on this.

[0052] Furthermore, the first digital probe 200 may also include a first digital microphone circuit board 204 and a first digital microphone 205. The first digital microphone circuit board 204 is embedded on the side of the first body 201 away from the first dustproof mesh 203. The first digital microphone circuit board 204 can be a printed circuit board (PCB), specifically integrating power management, signal processing chips, and external communication interfaces. The external communication interface may be based on pulse density modulation (PDM) or an integrated circuit built-in audio bus (Inter-IC Sound, I... 2 The interface implemented by S).

[0053] Furthermore, the first digital microphone circuit board 204 has a first via 2041, which is positioned directly opposite the central axis of the first outlet end 2023. The first via 2041 allows the ultrasonic waves converged by the first acoustic cavity 202 to pass through the circuit board and reach the microphone, preventing the circuit board from blocking the sound wave path.

[0054] The first digital microphone 205 is located on the side of the first via 2041 away from the first exit end 2023 and directly opposite the first exit end 2023, and the first digital microphone 205 is electrically connected to the first digital microphone circuit board 204.

[0055] In a specific implementation, the first digital microphone 205 can be a micro-electro-mechanical system (MEMS) digital microphone. This first digital microphone 205 integrates a MEMS diaphragm, a backplate, a charge pump, a preamplifier, and an analog-to-digital converter (ADC). The MEMS diaphragm and the backplate form a miniature capacitor; when an ultrasonic signal acts on the MEMS diaphragm, the diaphragm undergoes a minute displacement proportional to the sound pressure, causing a change in the electrode spacing between the MEMS diaphragm and the backplate, thereby altering the capacitance value and modulating an analog signal corresponding to the input ultrasonic signal. This analog signal is amplified by the preamplifier and then sent to the ADC for PDM or I / O processing. 2 The S-format analog-to-digital converter ultimately outputs a digital signal.

[0056] Subsequently, the first digital microphone 205 can be connected via its own digital interface (such as a PDM interface or I...). 2The S-interface is electrically connected to the first digital microphone circuit board 204, directly outputting the converted digital signal to the first digital microphone circuit board 204. The first digital microphone circuit board 204 can then perform level matching or format conversion on the digital signal before outputting it externally through the communication interface.

[0057] Figure 4 A cross-sectional view of the second digital probe provided in an embodiment of this application.

[0058] like Figure 2 and Figure 4 As shown, the second digital probe 300 includes a second body 301 and a second acoustic cavity 302; the second acoustic cavity 302 is formed in the second body 301. The second acoustic cavity 302 includes a second inlet end 3021, a second cavity 3022 and a second outlet end 3023. The second inlet end 3021 is formed on one side surface of the second body 301, and the second outlet end 3023 is formed on the other side surface of the second body 301. The second cavity 3022 gradually tightens from the second inlet end 3021 to the second outlet end 3023 to form a conical structure.

[0059] And a second dustproof net 303, which covers the second entrance end 3021 to form the receiving end of the second digital probe 300.

[0060] Additionally, the second digital probe 300 may also include a second digital microphone circuit board 304, which is embedded in the second body 301 on the side away from the second dustproof net 303; the second digital microphone circuit board 304 has a second through hole 3041, which is located opposite the second outlet end 3023.

[0061] Additionally, the second digital probe 300 may also include a second digital microphone 305, which is located on the side of the second via 3041 away from and directly opposite the second exit end 3023, and is electrically connected to the second digital microphone circuit board 304.

[0062] In some implementations, a first sealing gasket is provided between the first body 201 and the first digital microphone circuit board 204, and a second sealing gasket is provided between the second body 301 and the second digital microphone circuit board 304. The first and second sealing gaskets can be made of rubber or silicone material, used for cushioning and shock absorption to reduce noise. Figure 4 As shown, the second sealing gasket 306 is disposed between the second body 301 and the second digital microphone circuit board 304.

[0063] It is understandable that the structure and working principle of the second digital probe 300 are the same as those of the first digital probe 200, and will not be described again here.

[0064] In some implementations, the first digital probe 200 and the second digital probe 300 may have the same structure, and they are symmetrically arranged on both sides of the shielding structure 400.

[0065] It should also be noted that a filler is used between the first body 201 and the shielding slot 401, and a filler is used between the second body 301 and the shielding slot 401. The filler is resin (e.g., epoxy resin), rubber, or other flexible materials. This filler serves to fix and isolate sound. It is understood that, on the side of the first body 201 away from the receiving side (receiving end) of the first digital probe 200, in order to reduce the propagation of ultrasonic signals, this embodiment can fill the space between the first body 201 and the shielding slot 401 with filler, which can form an isolation layer. Similarly, filler can also be used between the second body 301 and the shielding slot 401, so that interference signals transmitted from the receiving side of the second digital probe 300 can also be attenuated. In actual molding processes, these fillers can be filled by potting, injection, or coating. After curing, they can both provide sound insulation and enhance overall mechanical stability.

[0066] Furthermore, in the embodiments of this application, at least three shielding structures 400 can be formed based on the different numbers and implementation methods of the shielding slots 401.

[0067] The first type of shielding structure 400 will be described below with reference to the attached diagram.

[0068] See also Figure 2 The first type of shielding structure 400 includes a shielding slot 401, and the shielding slot 401 is a single accommodating space formed by the first body 201, the second body 301 and the first housing 100. The space is directly filled with sound insulation medium 402, without the need for additional isolation plates, and the structure is compact.

[0069] In a specific implementation, a sound-insulating medium 402 with a matching size can be customized based on the preset size of the shielding slot 401. Then, the sound-insulating medium 402 is embedded between the first body 201 and the second body 301 to form a first shielding structure 400. Finally, filler material can be filled between the shielding structure 400 and the first digital probe 200 and the second digital probe 300 to form a complete structure of a dual ultrasonic partial discharge sensor with a shielding structure.

[0070] The second type of shielding structure 400 will be described below with reference to the attached diagram.

[0071] Figure 5This is a third cross-sectional view of a dual ultrasonic partial discharge sensor with a shielding structure provided in an embodiment of this application.

[0072] Figure 6 This is a fourth cross-sectional view of a dual ultrasonic partial discharge sensor with a shielding structure provided in an embodiment of this application.

[0073] It should be noted that, in order to ensure the structure is clear, Figure 5 and Figure 6 The fill material is not shown. Also, to facilitate observation of the internal components, the first body 201 and the second body 301 are drawn in wireframe form without fill.

[0074] like Figure 5 and Figure 6 As shown, the dual ultrasonic partial discharge sensor provided in this embodiment further includes a first pressure plate 403, a second pressure plate 404, and at least one intermediate partition plate 405 to form a plurality of shielding slots 401. In this case, the shielding slots 401 are the respective accommodating spaces formed by the first housing 100 and the first pressure plate 403, the intermediate partition plate 405, and the second pressure plate 404, which are distributed parallel to each other along the x-axis direction.

[0075] It is understandable that sound insulation media can be installed in multiple shielding slots 401. Through multi-stage series attenuation, crosstalk signals undergo reflection, absorption and scattering in each layer of shielding slot 401 in sequence, thereby significantly improving the overall sound insulation effect.

[0076] In some implementations, the inner wall of the first housing 100 may be provided with a slot 101, and each intermediate partition 405 may be inserted into the slot 101 to play a fixing role.

[0077] See also Figure 2 , Figure 4 , Figure 5 and Figure 6 In the first digital probe 200, the first outlet end 2023, the first through hole 2041, and the first digital microphone 205 of the first acoustic cavity 202 are sequentially distributed along the x-axis. In practical applications, to ensure the sound reception effect of the digital microphone, the first digital microphone 205 should be relatively close to the first body 201. In this embodiment, the first pressure plate 403 can be used to achieve this effect. Similarly, in the second digital probe 300, this embodiment can use the second pressure plate 404 to achieve this effect.

[0078] Specifically, a plurality of first pillars 4031 are provided on the side of the first pressure plate 403 near the first body 201, and the plurality of first pillars 4031 extend into the interior of the first body 201. A filler can be filled between the first pressure plate 403 and the first body 201. Since the first pressure plate 403 is inserted into the first body 201, and the first digital microphone circuit board 204 is embedded in the first body 201, under the combined squeezing action of the first pressure plate 403 and the filler, the first through hole 2041 can be tightly fitted with the first outlet end 2023, thereby ensuring the parallelism of the first digital microphone circuit board 204 and enhancing the sound reception effect of the first digital microphone 205.

[0079] In some implementations, there can be four first columns 4031, which are symmetrically arranged at the four corners of the first pressure plate 403.

[0080] See also Figure 6 The second pressure plate 404 has multiple second pillars 4041 on the side near the second body 301, and the multiple second pillars 4041 extend into the interior of the second body 301. A filler material can also be filled between the second pressure plate 404 and the second body 301. Since the second pressure plate 404 is inserted into the second body 301, and the second digital microphone circuit board 304 is embedded in the second body 301, the combined pressing action of the second pressure plate 404 and the filler material allows the second through hole 3041 to fit tightly against the second outlet end 3023, thereby ensuring the parallelism of the second digital microphone circuit board 304 and enhancing the sound pickup effect of the second digital microphone 305.

[0081] In some implementations, there can be four second columns 4041, which are symmetrically arranged at the four corners of the second pressure plate 404.

[0082] It is worth noting that the filler material can be resin, rubber, or other flexible materials. For example, the filler can be selected from silicone rubber, butyl rubber, ethylene propylene diene monomer rubber (EPDM), polyurethane flexible foam, or polyester fiber cotton, etc., and this application embodiment does not specifically limit it.

[0083] In some implementations, to accommodate the shapes of the first digital microphone circuit board 204 and the second digital microphone circuit board 304, the first pressure plate 403 and the second pressure plate 404 may have through holes of corresponding shapes. The specific method of opening these holes can be determined based on the actual situation, and this application embodiment does not impose specific limitations on this.

[0084] The third type of shielding structure, 400, will be described below.

[0085] This embodiment of the application can retain the first pressure plate 403 and the second pressure plate 404 in the second shielding structure 400, and remove the intermediate partition 405 to obtain the third shielding structure 400. In this way, a single accommodating space is formed between the first pressure plate 403 and the second pressure plate 404, containing only one shielding slot 401, in which a sound-insulating medium 402 can be disposed. This shielding structure 400 has a simpler structure and can also improve the sound reception effect.

[0086] The structure and materials of sound insulation medium 402 are described in detail below.

[0087] See also Figure 1 The sound insulation medium 402 can be a multi-layered structure, with an outer sound insulation layer 4021 and an inner absorption layer 4022, achieving an attenuation of 20dB / cm to 30dB / cm. Furthermore, the sound insulation layer 4021 is made of glass wool, polyester fiber cotton, polyurethane sound-absorbing cotton, rock wool, or butyl rubber. Glass wool has a porous and loose structure with fine fibers, achieving a transmission attenuation of 15-25dB / cm for 1-5MHz ultrasound, with optimal high-frequency attenuation. Polyester fiber cotton has uniform pores and good flexibility, achieving an attenuation of 8-15dB / cm for 0.5-2MHz ultrasound, suitable for low frequencies. Polyurethane sound-absorbing cotton is available in closed-cell / semi-open-cell structures. Rock wool has coarse fibers and large pores, providing good attenuation of low-frequency ultrasound below 1MHz (10-12dB / cm).

[0088] It is understandable that the material of the sound insulation layer 4021 can be matched with the frequency band of the ultrasonic signal to be attenuated. In practical applications, the embodiments of this application can select different sound insulation layers 4021 based on the ultrasonic signal conditions of the environment where the dual ultrasonic partial discharge sensors are located and the actual detection requirements. For example, when the target frequency band to be attenuated is a wide frequency band of 20kHz-100kHz, glass wool is used as the sound insulation layer 4021; when the target frequency band to be attenuated is a low frequency band of 20kHz-50kHz, polyester fiber cotton or butyl rubber is used as the sound insulation layer 4021.

[0089] Figure 7 This is a schematic diagram of an absorption layer provided in an embodiment of this application.

[0090] Furthermore, such as Figure 7 As shown, the absorption layer 4022 has a porous structure, which dissipates acoustic energy through multiple reflections, scattering, and friction of ultrasonic waves through the pores. The pores of the absorption layer 4022 can be filled with sealant 4023, which is specifically butyl sealant or acoustic silicone sealant; this embodiment does not specify the exact type.

[0091] Furthermore, depending on the shielding frequency band and processing conditions, the absorption layer 4022 can be selected from one of the following three structures.

[0092] ① Gradient-pore porous structure: The pore size of this structure decreases gradually from the outside to the inside, typically consisting of 2 to 3 pore size layers. The surface layer is a large-pore layer, with pore sizes ranging from 0.5 mm to 2 mm, used for scattering low-frequency ultrasound; the middle layer is a medium-pore layer, with pore sizes ranging from 0.1 mm to 0.5 mm, used for dissipating medium-frequency energy; the inner layer is a microporous layer, with pore sizes less than 0.1 mm, used for blocking high-frequency ultrasound. These pore size layers are arranged sequentially, with the pore size decreasing progressively. The overall porosity can be controlled between 70% and 85%, ensuring structural strength while maximizing the acoustic energy loss path. Commonly used materials include porous ceramics or gradient-foamed polyurethane.

[0093] ② Interconnected porous structure: The pores in this structure are interconnected, forming a three-dimensional network of channels. After ultrasound is incident, multiple reflections, refractions, and viscous friction occur within the channels. The open area ratio can be ≥80%, and the pore diameter can be matched to the length of the ultrasound wave, typically 1 / 5 to 1 / 3 of the wavelength. The channel curvature is greater than 1.5, meaning the ratio of the actual channel length to the straight-line length is greater than 1.5, to extend the sound energy loss path. The pore wall roughness can be controlled between 1μm and 5μm to enhance the frictional loss between the sound wave and the pore wall.

[0094] ③ Honeycomb porous composite structure: This structure has hexagonal honeycomb pores with a pore diameter of 5mm to 20mm and a honeycomb wall thickness of 0.1mm to 1mm. The gaps inside the honeycomb structure can be filled with butyl sealant or acoustic silicone sealant to further enhance sound energy dissipation. When ultrasonic waves encounter the honeycomb walls and pore edges, they undergo random scattering, dispersing energy from the propagation direction in all directions, resulting in a sharp decrease in the signal strength in the forward propagation direction.

[0095] All three porous structures are filled with sealant 4023 to enhance the shielding effect.

[0096] In some implementations, the thickness of the sound insulation layer 4021 can be 5mm-15mm, for example, 10mm; the thickness of the absorption layer 4022 can be 10mm-20mm, for example, 15mm. It should be noted that the above thickness range can be adjusted according to the ultrasonic frequency band to be attenuated: for low-frequency bands (such as 20kHz-50kHz), the thickness of the sound insulation layer 4021 can be appropriately increased to enhance reflection loss; for wide-frequency bands (such as 20kHz-100kHz), the thickness of the absorption layer 4022 can be appropriately increased to enhance the porous sound absorption effect. This application does not specifically limit the specific thickness of the sound insulation layer 4021 and the absorption layer 4022.

[0097] It is worth noting that when there are multiple shielding slots 401, different shielding slots 401 are used to accommodate the same or different sound insulation media 402. Different sound insulation media 402 refer to different materials used for the sound insulation layer 4021 and / or different structures used for the absorption layer 4022. The sound insulation media 402 can be selected based on actual needs, and this application embodiment does not specifically limit it in this regard.

[0098] It should also be noted that the outer surface of the first housing 100 near the second digital probe 300 is a frosted reflective surface, which is used to increase the reflection of ultrasonic signals from the external environment by the first housing 100.

[0099] In this embodiment of the application, in order to reduce the derivative interference of ultrasonic signals in the environment on the internal probe of the sensor, a reflective layer can be added to the surface of the first housing 100. In this way, at least four shielding structures can be formed, namely the reflective layer, the isolation layer, the sound insulation layer 4021, and the absorption layer 4022 mentioned above.

[0100] In practical applications, the embodiments of this application can perform sandblasting on the outer surface of the first housing 100 near the second digital probe 300 to form a sandblasted surface, i.e., a frosted reflective surface. The surface roughness Ra of this frosted reflective surface can be less than 0.15 mm. It is understood that the reflection characteristics of the frosted reflective surface are determined by the ratio of surface roughness to the wavelength of the sound wave. When the surface roughness is much smaller than the wavelength of the sound wave, the frosted surface can be approximated as a smooth surface, and the reflection is mainly specular reflection; when the surface roughness is greater than half the wavelength of the sound wave, diffuse reflection dominates, and the incident wave is scattered in many directions. At this time, interference signals in the external environment can hardly form a stable transmitted wave to enter the interior of the first housing 100, which can improve the shielding effect.

[0101] Furthermore, the higher the frequency of the sound wave and the shorter the wavelength, the stronger the scattering effect of the high-frequency sound wave on a surface with the same roughness, and the more significant the attenuation of the reflected signal. The incident angle also affects the reflection characteristics: with perpendicular incidence, the isotropic scattering is stronger; with oblique incidence, the direction distribution of diffuse reflection will shift with the incident angle, and may be accompanied by more wave mode conversion, such as the conversion of longitudinal waves to transverse waves, further dispersing the sound energy. At the same time, the acoustic impedance difference between air and solid ground sand interface is extremely large, so even if diffuse reflection occurs, some energy is still reflected back into the air; while the acoustic impedance difference between liquid and solid ground sand interface is smaller, and the transmission loss will further reduce the reflected energy. The sensor of this application mainly operates in an air environment, so the ground sand reflective surface can effectively reflect external ultrasonic interference back into the air, preventing it from penetrating the housing and entering the internal probe.

[0102] Taking the application scenario of this application as an example: the wavelength of a 40kHz ultrasonic wave in air is approximately 8.5mm. In some implementations, this application sets the surface roughness Ra of the frosted reflective surface to be less than 0.15mm, i.e., 150μm. In other implementations, this application sets the surface roughness Ra of the frosted reflective surface to 5mm-6mm. It is understood that these surface roughness values ​​are only illustrative examples, and the specific values ​​can be adjusted based on actual needs.

[0103] It should be noted that the surface of the first housing 100 on the side where the first digital probe 200 is located does not need to be sandblasted. This is because the first digital probe 200 is used to acquire the complete ultrasonic signal emitted from inside the device under test. If the surface of the first housing 100 on this side is too rough, the strong reflection will cause signal clutter inside the cabinet, affecting the accuracy of acquisition. Therefore, this application only provides a frosted reflective surface on the outer surface of the side closest to the second digital probe 300 to shield against external environmental interference, while ensuring that the first digital probe 200 can completely receive the internal signal.

[0104] Understandably, during the actual monitoring phase, the side of the first housing 100 covered by the first dustproof net 203 can be close to or attached to the device under test.

[0105] In some implementations, a third sealing gasket is provided on the outer surface of the first housing 100 near the first digital probe 200. In practical applications, the third sealing gasket can specifically be located on the side of the first housing 100 that covers the first dustproof mesh 203 (i.e., the target side of the first housing 100), and the third sealing gasket can be made of rubber or silicone. This further shields environmental interference signals, enhances the reliability of the connection between the sensor probe and the cabinet, and provides cushioning and shock absorption. It is understood that this third sealing gasket does not cover the first dustproof mesh 203.

[0106] In some implementations, the dual ultrasonic partial discharge sensor may further include a first antenna for communicative connection with the first digital microphone circuit board 204 and the second digital microphone circuit board 304. Based on this first antenna, the dual ultrasonic partial discharge sensor can upload the output data of the first digital microphone circuit board 204 and the second digital microphone circuit board 304 to an external device. In this embodiment, the output data of the first digital microphone circuit board 204 can be referred to as internal partial discharge data, and the output data of the second digital microphone circuit board 304 can be referred to as external ambient noise data.

[0107] In some implementations, the first antenna can be connected to the first digital microphone circuit board 204 or the second digital microphone circuit board 304 using flexible printed circuit (FPC) cables, onboard microstrip lines, etc. In practical applications, the first antenna can be disposed inside the first housing 100, for example, on the intermediate partition 405. The specific arrangement can be adjusted based on the actual situation, and this application embodiment does not impose any specific limitations on this.

[0108] To verify the anti-crosstalk, noise reduction, and shielding effects of the dual ultrasonic partial discharge sensor, comparative simulation experiments were conducted in the embodiments of this application. The simulation experiments used a standard 40kHz sound source to emit ultrasonic signals, and tested the signal acquisition of the dual ultrasonic digital microphone probes under two conditions: with and without shielding structure 400.

[0109] The simulation experimental equipment includes: a standard 40kHz ultrasonic signal generator, dual ultrasonic partial discharge sensors (including a first digital probe 200 and a second digital probe 300), and a signal acquisition and analysis system. The dual ultrasonic partial discharge sensors have two states: State A: without shielding structure (i.e., the sound insulation medium 402 in the middle layer is removed, and there is no shielding between the first digital probe 200 and the second digital probe 300); State B: with shielding structure (i.e., the sound insulation medium 402 of the embodiment of this application is fully assembled).

[0110] The experimental steps included: emitting a stable ultrasonic signal from a standard 40kHz sound source outside the cabinet; and acquiring signals using dual ultrasonic partial discharge sensors in states A and B, respectively. "Emitting a stable ultrasonic signal from a standard 40kHz sound source outside the cabinet" meant moving the first digital probe 200 away from the sound source and the second digital probe 300 towards it, to specifically verify the crosstalk suppression effect of the shielding structure on the first digital probe 200, thus ensuring that the first digital probe 200 could acquire a clean partial discharge signal with a high signal-to-noise ratio inside the cabinet in practical applications. Afterwards, the amplitude of the acquired signal was read (the average of the peak-to-peak values ​​was taken as the amplitude signal Ameas), and environmental noise floor data was set (the noise floor amplitude Aref was taken as a reference of 40mV). The amplitude was converted to a signal strength decibel value using a formula, and finally, the signal attenuation in the two states was compared.

[0111] Figure 8 The waveform diagram is obtained when the structure is not shielded, as provided in the embodiment of this application.

[0112] Figure 8 (a) is the time-domain plot of the original signal acquired by the first digital probe 200 before shielding. Figure 8 Image (b) shows the frequency domain diagram of the original signal acquired by the first digital probe 200 before shielding. Figure 8As shown, the amplitude of the signal (vertical axis) is high and the waveform oscillation is obvious, indicating that the 40kHz ultrasound signal can strongly penetrate the gap between the second digital probe 300 and the first digital probe 200 without shielding attenuation, causing significant crosstalk.

[0113] Figure 9 The waveform diagram is collected when the shielded structure is provided in the embodiment of this application.

[0114] Figure 9 (a) is the time-domain plot of the original signal acquired by the first digital probe 200 after shielding. Figure 9 Image (b) shows the frequency domain diagram of the original signal acquired by the first digital probe 200 after shielding. Figure 9 As shown, the amplitude of the amplitude signal (vertical axis) is relative to... Figure 8 The signal was significantly reduced, and the waveform became flatter, approaching the noise floor level, indicating that the shielding structure 400 effectively attenuated the 40kHz ultrasonic signal.

[0115] Figure 10 This is a signal strength comparison diagram provided for an embodiment of this application.

[0116] In this application, signal intensity can be measured in ultrasonic decibels (dB). The relationship between dB value and amplitude in ultrasound is logarithmic proportionality. The calculation formula is: dB = 20lg(Ameas / Aref); Where: dB is the ultrasonic dB value, Ameas is the signal amplitude, Aref is the reference standard, and 40mV is used as the reference standard in the simulation experiment (the noise floor is 40mV).

[0117] Figure 10 (a) shows the signal intensity diagram corresponding to the original signal acquired by the first digital probe 200 before shielding. Figure 10 Image (b) shows the signal intensity diagram corresponding to the original signal acquired by the first digital probe 200 after shielding. For example... Figure 10 As shown, the acoustic attenuation corresponding to the first digital probe 200 is approximately 72.22dB - 38.36dB = 33.86dB, which is around 35dB.

[0118] Based on the above, the shielding performance across the entire frequency range of 20kHz to 100kHz was further tested by adjusting the material of the sound insulation layer 4021 and the pore structure of the absorption layer 4022 in the sound insulation medium 402. Simulation results show that the average sound attenuation is greater than 50dB across the entire frequency range of 20kHz to 100kHz; for specific frequency points (such as 40kHz and 80kHz), a shielding effect of greater than 60dB can be achieved. Therefore, the shielding structure 400 can achieve significant signal attenuation and effectively reduce crosstalk between probes.

[0119] The simulation data described above verifies the technical advantages of the dual ultrasonic partial discharge sensor provided in this application embodiment in the following aspects: Significant anti-crosstalk effect: The shielding structure can achieve 35dB to 46dB of acoustic attenuation, greatly reducing ultrasonic crosstalk between the first digital probe 200 and the second digital probe 300; Wideband applicability: By selecting different combinations of sound insulation media, it can cover the wideband ultrasonic signal shielding requirements from 20kHz to 100kHz, especially making up for the lack of low-frequency signal acquisition. Adjustable shielding performance: The replaceable shielding slot 401 structure allows for flexible configuration of the sound insulation layer 4021 material and the pore shape of the absorption layer 4022 according to the target frequency band, achieving targeted and efficient shielding.

[0120] As can be seen from the above, the embodiments of this application provide a dual ultrasonic partial discharge sensor with a shielding structure, which has the following beneficial effects: it can realize the acquisition of ultrasonic wide-band signals; it is suitable for places with strong electromagnetic interference, and is less affected by environmental interference and production process interference, and has good stability; the crosstalk between the internal and external working of the dual ultrasonic microphone probes is greatly reduced, providing cleaner data for subsequent signal acquisition and analysis.

[0121] Figure 11 This is a schematic diagram of the partial discharge sensor terminal provided in an embodiment of this application.

[0122] like Figure 11 As shown, this application embodiment also provides a partial discharge sensor terminal, which includes at least the dual ultrasonic partial discharge sensor 500 with a shielding structure as described in the previous embodiment. Further, the partial discharge sensor terminal also includes a second housing 600, to which the dual ultrasonic partial discharge sensor 500 with the shielding structure can be fixed. Additionally, the partial discharge sensor terminal may also include a buffer pad 700, which is disposed on the target side of the second housing 600. The target side refers to the side of the first housing 100 covered by the first dustproof net 203, to further shield environmental interference signals, enhance the connection reliability between the sensor probe and the cabinet, and provide cushioning and shock absorption.

[0123] In some implementations, a magnet may also be provided between the second housing 600 and the buffer pad 700. This magnet is used to attract the partial discharge sensor terminal to the device under test to achieve stable monitoring.

[0124] Furthermore, the partial discharge sensor terminal may also include a temperature sensor, which is used to monitor the ambient temperature of the device under test and provide auxiliary criteria for partial discharge analysis.

[0125] Furthermore, the partial discharge sensor terminal may also include a battery to power the dual ultrasonic partial discharge sensor 500 with a shielded structure and the temperature sensor, enabling the partial discharge sensor terminal to work independently in scenarios without an external power source.

[0126] Furthermore, the partial discharge sensor terminal may also include a microcontroller unit (MCU) and a second antenna. The MCU and second antenna can be housed inside a second housing. The second antenna can be used to communicate with the first antenna in the shielded dual ultrasonic partial discharge sensor 500. In practical applications, through the second antenna, the MCU can receive ultrasonic monitoring data transmitted by the shielded dual ultrasonic partial discharge sensor 500 via the first antenna, as well as temperature data collected by a temperature sensor. The MCU can then parse, store, and package the data, and upload the processed data to a remote monitoring platform via the second antenna, thereby achieving the purpose of partial discharge monitoring and analysis.

[0127] In some implementations, the second antenna can communicate via wireless LAN, low-power wide-area network, or power grid, etc., and this application embodiment does not specifically limit this. Furthermore, the partial discharge sensor terminal also supports wired communication, such as Ethernet, RS485, or Controller Area Network (CAN) communication, and this application embodiment does not specifically limit this.

[0128] Understandably, this partial discharge sensor terminal can be configured to perform the following steps: S100: Receives internal partial discharge data and external environmental noise data uploaded by at least one shielded dual ultrasonic partial discharge sensor 500 via a second antenna; S200: Performs data verification and format conversion on internal partial discharge data and external environmental noise data to obtain preprocessed internal partial discharge data and external environmental noise data; S300: Uploads pre-processed internal partial discharge data and external environmental noise data to a remote monitoring platform.

[0129] Understandably, the remote monitoring platform can be configured to perform the following steps: S400: Based on the preprocessed internal partial discharge data and external environmental noise data, differential operation or adaptive noise cancellation is performed to filter out environmental interference and obtain the denoised partial discharge data. S500: Based on the denoised partial discharge data, extract characteristic parameters such as discharge amplitude, phase, and pulse frequency; S600: Determines whether the device under test has partial discharge based on characteristic parameters.

[0130] It is readily understood that, based on the several embodiments provided in this application, those skilled in the art can combine, split, or reorganize the embodiments of this application to obtain other embodiments, none of which exceed the protection scope of this application.

[0131] The above detailed embodiments further illustrate the purpose, technical solution, and beneficial effects of the embodiments of this application. It should be understood that the above are merely specific embodiments of the embodiments of this application and are not intended to limit the protection scope of the embodiments of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solutions of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A dual ultrasonic partial discharge sensor with a shielding structure, characterized in that, include: First housing (100); A first digital probe (200) and a second digital probe (300) are symmetrically distributed inside the first housing (100). The receiving end of the first digital probe (200) is located on one side of the first housing (100) and is used to attach to the device under test to receive ultrasonic signals emitted from inside the device under test. The receiving end of the second digital probe (300) is located on the other side of the first housing (100) and is used to receive ultrasonic signals from the external environment of the device under test. The outer surface of the first housing (100) near the second digital probe (300) is a frosted reflective surface, which is used to increase the reflection of ultrasonic signals from the external environment by the first housing (100); A shielding structure (400) is located between the first digital probe (200) and the second digital probe (300). The shielding structure (400) includes at least one shielding slot (401) for accommodating a sound-insulating medium (402) to attenuate ultrasonic signals propagating between the first digital probe (200) and the second digital probe (300).

2. The dual ultrasonic partial discharge sensor with a shielding structure according to claim 1, characterized in that, The first digital probe (200) includes: First ontology (201); The first acoustic cavity (202) includes a first inlet end (2021), a first cavity body (2022), and a first outlet end (2023). The first inlet end (2021) is located on one side surface of the first body (201), and the first outlet end (2023) is located on the other side surface of the first body (201). The first cavity body (2022) gradually narrows from the first inlet end (2021) to the first outlet end (2023) to form a conical structure. A first dustproof net (203) covers the first entrance end (2021) to form the receiving end of the first digital probe (200); The first digital microphone circuit board (204) is embedded in the first body (201) on the side away from the first dustproof mesh (203); the first digital microphone circuit board (204) has a first through hole (2041), and the opening position of the first through hole (2041) is directly opposite the first outlet end (2023). A first digital microphone (205) is located on the side of the first via (2041) away from the first outlet end (2023) and directly opposite the first outlet end (2023), and the first digital microphone (205) is electrically connected to the first digital microphone circuit board (204). The second digital probe (300) includes: Second body (301); The second acoustic cavity (302) includes a second inlet end (3021), a second cavity body (3022), and a second outlet end (3023). The second inlet end (3021) is located on one side surface of the second body (301), and the second outlet end (3023) is located on the other side surface of the second body (301). The second cavity body (3022) gradually narrows from the second inlet end (3021) to the second outlet end (3023) to form a conical structure. A second dustproof net (303) covers the second entrance end (3021) to form the receiving end of the second digital probe (300); The second digital microphone circuit board (304) is embedded in the second body (301) on the side away from the second dustproof mesh (303); the second digital microphone circuit board (304) has a second through hole (3041), and the opening position of the second through hole (3041) is directly opposite the second outlet end (3023). The second digital microphone (305) is located on the side of the second via (3041) away from the second exit end (3023) and directly opposite the second exit end (3023), and the second digital microphone (305) is electrically connected to the second digital microphone circuit board (304).

3. The dual ultrasonic partial discharge sensor with a shielding structure according to claim 2, characterized in that, The first body (201) and the shielding slot (401) are filled with a filler, and the second body (301) and the shielding slot (401) are filled with the filler, which is resin or rubber.

4. The dual ultrasonic partial discharge sensor with a shielding structure according to claim 3, characterized in that, The shielding slot (401) is the accommodating space formed by the first housing (100) and the parallel distributed first pressure plate (403) and second pressure plate (404); The filler is filled between the first pressure plate (403) and the first body (201), and the filler is filled between the second pressure plate (404) and the second body (301); The first pressure plate (403) is provided with a plurality of first pillars (4031) on the side near the first body (201), and the plurality of first pillars (4031) extend into the interior of the first body (201) so that the first through hole (2041) fits tightly with the first outlet end (2023); The second pressure plate (404) is provided with a plurality of second pillars (4041) on the side near the second body (301). The plurality of second pillars (4041) extend into the interior of the second body (301) so that the second through hole (3041) fits tightly with the second outlet end (3023).

5. The dual ultrasonic partial discharge sensor with a shielding structure according to claim 4, characterized in that, At least one intermediate partition (405) is provided between the first pressure plate (403) and the second pressure plate (404), and the intermediate partition (405) is parallel to the first pressure plate (403) and the second pressure plate (404) to form a plurality of the shielding slots (401).

6. The dual ultrasonic partial discharge sensor with a shielding structure according to claim 3, characterized in that, A first sealing gasket is provided between the first body (201) and the first digital microphone circuit board (204), and a second sealing gasket is provided between the second body (301) and the second digital microphone circuit board (304).

7. The dual ultrasonic partial discharge sensor with a shielding structure according to claim 1, characterized in that, The sound insulation medium (402) has a multi-layered structure, with an outer layer of sound insulation layer (4021) and an inner layer of absorption layer (4022). The sound insulation layer (4021) is made of glass wool, polyester fiber wool, polyurethane sound-absorbing wool, rock wool or butyl rubber. The absorbent layer (4022) is a gradient pore size porous structure, an open-pore interconnected porous structure, or a honeycomb porous composite structure, and the pores of the absorbent layer (4022) are filled with sealant (4023); wherein, the gradient pore size porous structure has at least two levels of pore size layers arranged sequentially from the outside to the inside, and the pore size of each level of pore size layer decreases gradually; the open-pore interconnected porous structure has interconnected three-dimensional mesh pores; the honeycomb porous composite structure has hexagonal honeycomb pores.

8. The dual ultrasonic partial discharge sensor with a shielding structure according to claim 7, characterized in that, The material of the sound insulation layer (4021) is matched with the frequency band of the ultrasonic signal to be attenuated; When there are multiple shielding slots (401), different shielding slots (401) are used to accommodate the same or different sound insulation media (402). Different sound insulation media (402) refer to different materials of the sound insulation layer (4021) and / or different structures of the absorption layer (4022).

9. The dual ultrasonic partial discharge sensor with a shielding structure according to claim 1, characterized in that, A third sealing gasket is provided on the outer surface of the first housing (100) near the first digital probe (200).

10. A partial discharge sensor terminal, characterized in that, It includes at least the dual ultrasonic partial discharge sensor with a shielding structure as described in any one of claims 1-9.

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