A multi-parameter rapid synchronous detection device and method for insulating oil

Abstract

This invention relates to the field of high-voltage insulation and intelligent sensing monitoring in power systems, specifically to a rapid synchronous detection device and method for multiple parameters of insulating oil. The device comprises a fluid drive unit, an acoustic-electrical stratification test pipeline, a breakdown test unit, and a self-healing damping valve. The system utilizes the synergistic effect of ultrasonic standing wave field and dielectric electrophoresis to construct a virtual stratified structure within the pipeline, consisting of a central gas-rich core flow and a peripheral pure circulation flow. Its core component is a hollow, breathable fiber membrane tube for degassing analysis, while simultaneously using an external shielded electrode to measure the dielectric loss of the bubble-free oil. This invention resolves the fluid dynamics contradiction between the highly disturbed fluid environment required for oil-gas separation and the undisturbed steady-state laminar flow environment required for dielectric loss measurement, thus achieving rapid synchronous detection of multiple parameters of insulating oil.

Description

Technical Field

[0001] This invention relates to the field of high-voltage insulation technology and intelligent sensing monitoring in power systems, specifically to a rapid synchronous detection device and method for multiple parameters of insulating oil. Background Technology

[0002] In the insulation condition monitoring of high-voltage equipment such as power transformers, the dissolved gas content, dielectric loss factor, and breakdown voltage of insulating oil are key indicators for assessing the health status of the equipment. These indicators require periodic or real-time comprehensive analysis. Existing detection technologies generally face inherent contradictions in the requirements of the fluid dynamic environment when attempting to simultaneously detect the above multiple parameters. Specifically, efficient oil-gas separation and degassing analysis usually require a highly disturbed dynamic flow field environment to enhance mass transfer efficiency, while high-precision dielectric loss measurement strictly requires a stable laminar flow environment free from disturbances and bubble interference to prevent electric field distortion and measurement errors. Existing solutions cannot simultaneously construct and maintain these two diametrically opposed physical field states in the same fluid loop, resulting in parameters often having to be measured independently through physical isolation or time-sharing methods. This leads to fragmented detection processes, slow response speeds, and an inability to truly reflect the comprehensive insulation characteristics of the same oil sample at the same moment. Furthermore, as a destructive test, the carbonized particles generated by the breakdown voltage test can easily remain or flow back in the pipeline, contaminating upstream precision sensors. Existing devices lack effective internal self-cleaning mechanisms, making it difficult to ensure the continuity and robustness of online monitoring.

[0003] Therefore, how to resolve the flow field conflict between dynamic mixed flow degassing and steady-state laminar flow measurement in a single detection system, and how to achieve automatic sewage discharge and media renewal after destructive testing, in order to improve the efficiency and accuracy of multi-parameter synchronous detection, has become an urgent technical problem to be solved. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a rapid synchronous detection device and method for multiple parameters of insulating oil, specifically as follows:

[0005] A rapid synchronous detection device for multiple parameters of insulating oil includes:

[0006] Fluid drive unit, acoustic-electric delamination test pipeline, breakdown test unit, self-healing damping valve and controller;

[0007] The fluid drive unit is fixed to the base and includes a micro screw pump and a rigid transition pipe connected to its output end. The end of the rigid transition pipe is provided with a sealing joint.

[0008] The acoustic-electric stratification test pipeline is connected downstream of the fluid drive unit. The main body is a borosilicate glass tube. A piezoelectric ceramic transducer is bonded to the circumference of the outer wall of the borosilicate glass tube. A spiral interlocking comb-shaped electrode is deposited on the inner wall of the borosilicate glass tube. A hollow, breathable fiber membrane tube is coaxially suspended inside the downstream section. A ring-shaped metal shielding electrode is wrapped around the outer wall of the borosilicate glass tube at the corresponding position. The outer diameter of the hollow, breathable fiber membrane tube is smaller than the inner diameter of the borosilicate glass tube, forming a ring-shaped flow channel.

[0009] The breakdown test unit is connected to the outlet end of the acoustic-electric delamination test pipeline, and includes an insulation test cavity and two hemispherical discharge electrodes arranged opposite each other inside. The bottom of the insulation test cavity has a drain port, and the side of the insulation test cavity has a main outlet that connects to the circulation loop.

[0010] The self-healing damping valve is connected to the drain outlet and includes a three-way diversion pipe, a damping piston slidingly installed in a side branch pipe, and a return spring against its back. The side branch pipe wall has a pressure relief hole. It is configured to connect the pressure relief hole and the drain outlet when the damping piston is pressed and retracts to a predetermined stroke. The controller is connected to the fluid drive unit, the acoustic-electrical stratification test pipeline, the breakdown test unit, and the self-healing damping valve.

[0011] In one possible implementation, the stator of the micro-screw pump is made of an elastomer material, the screw rotor of the micro-screw pump is a stainless steel screw, one end of the rigid transition tube is connected to the micro-screw pump via a flange, and the other end is connected to a borosilicate glass tube. The sealing joint is a compression fitting.

[0012] In one possible implementation, there are four piezoelectric ceramic transducers arranged in a cross-shaped symmetrical distribution along the circumference of the borosilicate glass tube, and the interlocking comb-shaped electrodes are wound in a double helix structure along the inner wall of the borosilicate glass tube.

[0013] In one possible implementation, the inner cavity of the hollow permeable fiber membrane tube is connected to the gas inlet of the gas detector, and the annular metal shielding electrode and the conductive medium inside the hollow permeable fiber membrane tube constitute a coaxial cylindrical capacitor.

[0014] In one possible implementation, the bottom of the insulation test chamber is funnel-shaped, the drain outlet is located at the lowest point of the funnel-shaped structure, and the side of the insulation test chamber has a main outlet.

[0015] In one possible implementation, the straight end of the three-way shunt tube is constructed as a sealed blind end, one end of the return spring abuts against the back of the damping piston, and the other end abuts against the end cap of the side branch tube.

[0016] In one possible implementation, the borosilicate glass tube has high sound transmittance, and the hollow, breathable fiber membrane tube is made of hydrophobic polypropylene material.

[0017] A rapid and synchronous detection method for multiple parameters of insulating oil includes:

[0018] S1. Control the fluid drive unit to work at the initial preset speed to push the insulating oil to be tested into the acoustic-electrical stratification test pipeline and establish a laminar background flow field.

[0019] S2. Control the operation of the acoustic-electric stratification test pipeline, apply a driving voltage to the piezoelectric ceramic transducer to generate an ultrasonic standing wave field, and apply an alternating electric field to the interlocked comb electrode to generate dielectric force, thus constructing a central gas-rich core flow and a peripheral pure circulation flow on the pipeline cross-section of the acoustic-electric stratification test pipeline.

[0020] S3. Real-time monitoring of the impedance phase angle of the piezoelectric ceramic transducer, and feedback adjustment of the rotation speed of the fluid drive unit and the driving voltage amplitude of the piezoelectric ceramic transducer based on the jitter characteristics of the impedance phase angle to maintain the stability of the flow field stratification.

[0021] S4. Gas permeation extraction of the central gas-rich core flow is performed using a hollow permeable fiber membrane tube, and the dielectric loss factor of the peripheral pure circulation is measured using an annular metal shielding electrode.

[0022] S5. Control the flow of insulating oil into the breakdown test unit and apply voltage across the two hemispherical discharge electrodes to perform insulation performance testing.

[0023] S6. When a breakdown occurs and a fluid shock wave is generated, the shock wave pressure is used to push the damping piston of the self-healing damping valve to compress the reset spring and retract.

[0024] S7. When the damping piston retracts to expose the pressure relief hole, it discharges the deteriorated oil containing carbonized particles.

[0025] S8. The damping piston is pushed back to reset by the elastic force of the reset spring to reseal the pressure relief hole. Under the continuous driving action of the fluid drive unit, fresh oil automatically fills the insulation test chamber. Steps S1 to S8 are executed in a cycle.

[0026] In one possible implementation, step S3, which involves adjusting the rotational speed of the fluid drive unit and the driving voltage amplitude of the piezoelectric ceramic transducer based on the feedback characteristics of the impedance phase angle jitter, specifically includes:

[0027] Determine whether the jitter amplitude of the impedance phase angle exceeds the preset baseline envelope range;

[0028] If so, it is determined that microbubbles have escaped, and the fluid drive unit is controlled to reduce the speed of the micro-screw pump and the acoustic-electric stratification test pipeline is controlled to increase the driving voltage of the piezoelectric ceramic transducer.

[0029] In one possible implementation, step S5 includes:

[0030] Real-time acquisition of pulse current flowing through the two hemispherical discharge electrodes;

[0031] Calculate the time derivative rate of change of the pulse current;

[0032] Determine whether the rate of change of the time derivative exceeds the electron avalanche precursor threshold;

[0033] If so, the voltage is cut off and the breakdown voltage is calculated based on the current voltage value, or the voltage is maintained to allow breakdown, thereby triggering the self-healing sewage discharge steps in steps S6 to S8.

[0034] The present invention has the following beneficial effects:

[0035] 1. This invention generates an ultrasonic standing wave field through a piezoelectric ceramic transducer in an acoustic-electric stratification test pipeline. Combined with the dielectric force generated by interlocked comb electrodes, a central gas-rich core flow and a peripheral pure circulation flow are constructed on the cross-section of the acoustic-electric stratification test pipeline. The central gas-rich core flow uses a hollow, breathable fiber membrane tube for gas permeation extraction, while the peripheral pure circulation flow uses an annular metal shielded electrode to measure the dielectric loss factor. This design simultaneously satisfies the mass transfer efficiency required for gas extraction and the laminar flow stability required for dielectric loss measurement in the same fluid loop, overcoming the limitations of the prior art where parameters need to be measured in time or in isolation due to conflicts in the fluid dynamic environment.

[0036] 2. This invention incorporates a self-healing damping valve connected to the drain port of the breakdown test unit. When a breakdown occurs and generates a fluid shock wave, the shock wave pressure pushes the damping piston of the self-healing damping valve to compress the reset spring and retract. When the damping piston retracts to expose the pressure relief hole, deteriorated oil containing carbonized particles is discharged. After the shock wave dissipates, the spring force of the reset spring pushes the damping piston to reset and re-seal the pressure relief hole. Under the continuous driving action of the fluid drive unit, fresh oil automatically fills the insulation test cavity. This mechanism can complete self-cleaning and medium replacement without external control, effectively preventing backflow contamination of upstream test pipelines by carbonized particles, and significantly improving the continuous operation capability and robustness of the online monitoring system.

[0037] 3. This invention monitors the impedance phase angle and its jitter characteristics of the piezoelectric ceramic transducer in real time to determine whether the jitter amplitude of the impedance phase angle exceeds the preset baseline envelope range. If so, it determines that microbubbles have escaped, and uses feedback to adjust and control the fluid drive unit to reduce the speed of the micro-screw pump, and controls the acoustic-electric stratification test pipeline to increase the driving voltage of the piezoelectric ceramic transducer. This closed-loop control strategy effectively maintains the stability of the flow field stratification, thereby ensuring the accuracy of gas detection and insulation characteristic measurement. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall external structure of the device;

[0039] Figure 2 This is a schematic diagram of the internal structure of the device;

[0040] Figure 3 This is a schematic diagram of the acoustic-electrical stratification test pipeline structure.

[0041] Figure 4 This is a schematic diagram of the insulation test chamber structure of the device;

[0042] Figure 5 yes Figure 4 A schematic diagram of the enlarged structure of node A in the middle;

[0043] Figure 6 This is a flowchart of the method of the present invention.

[0044] In the diagram: 100, fluid drive unit; 110, micro screw pump; 111, stator; 112, screw rotor; 120, rigid transition tube; 121, flange; 122, sealing joint; 200, acoustic-electrical stratification test pipeline; 210, borosilicate glass tube; 220, piezoelectric ceramic transducer; 230, interlocking comb electrode; 240, hollow breathable fiber membrane tube; 250, annular metal shielding electrode; 260, annular flow channel; 300, breakdown test unit; 310, insulation test chamber; 320, hemispherical discharge electrode; 330, funnel-shaped structure; 340, drain outlet; 350, main outlet; 400, self-healing damping valve; 410, three-way diversion pipe; 420, side branch pipe; 430, damping piston; 440, return spring; 450, pressure relief hole. Detailed Implementation

[0045] 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, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0046] Example 1:

[0047] Please see Figures 1-5 A rapid synchronous detection device for multiple parameters of insulating oil, comprising:

[0048] Fluid drive unit 100, acoustic-electrical delamination test pipeline 200, breakdown test unit 300, self-healing damping valve 400 and controller;

[0049] The fluid drive unit 100 is fixed to the base and includes a micro screw pump 110 and a rigid transition pipe 120 connected to its output end. The rigid transition pipe 120 is provided with a sealing joint 122 at its end.

[0050] The acoustic-electric stratification test pipeline 200 is connected downstream of the fluid drive unit 100. The main body is a borosilicate glass tube 210. A piezoelectric ceramic transducer 220 is bonded to the outer circumference of the borosilicate glass tube 210. A spiral interlocking comb-shaped electrode 230 is deposited on the inner wall of the borosilicate glass tube 210. A hollow, breathable fiber membrane tube 240 is coaxially suspended inside the downstream section. A ring-shaped metal shielding electrode 250 is wrapped around the outer wall of the borosilicate glass tube 210 at the corresponding position. The outer diameter of the hollow, breathable fiber membrane tube 240 is smaller than the inner diameter of the borosilicate glass tube 210, forming a ring-shaped flow channel 260.

[0051] The breakdown test unit 300 is connected to the outlet end of the acoustic-electric delamination test pipeline 200, including an insulation test cavity 310 and two hemispherical discharge electrodes 320 arranged opposite each other inside. The bottom of the insulation test cavity 310 has a drain port 340, and the side of the insulation test cavity 310 has a main outlet 350 that connects to the circulation loop.

[0052] The self-healing damping valve 400 is connected to the drain port 340 and includes a three-way diversion pipe body 410, a damping piston 430 slidingly mounted in a side branch pipe 420, and a return spring 440 against its back. The side branch pipe wall has a pressure relief hole 450. It is configured to open the pressure relief hole 450 and the drain port 340 when the damping piston 430 is pressed and retracts to a predetermined stroke. The controller is connected to the fluid drive unit 100, the acoustic-electrical stratification test pipeline 200, the breakdown test unit 300, and the self-healing damping valve 400.

[0053] This embodiment provides a rapid synchronous detection device for multiple parameters of insulating oil, aiming to solve the fluid dynamics contradiction between the highly disturbed fluid environment required for oil-gas separation and the undisturbed steady-state laminar flow environment required for dielectric loss measurement in the prior art. The device constructs a continuous flow detection system based on multi-physics field control through the series coupling of a fluid drive unit 100, an acoustic-electric stratification test pipeline 200, a breakdown test unit 300, and a self-healing damping valve 400. Among them, the fluid drive unit 100 serves as a power source, responsible for pushing the insulating oil to be tested into the system in a pulsation-free laminar flow state, providing a stable background flow field for subsequent acoustic stratification.

[0054] The acoustic-electric stratification test pipeline 200 utilizes the ultrasonic standing wave field generated by the piezoelectric ceramic transducer 220 and the dielectric force generated by the interlocked comb electrode 230 to construct a virtual fluid stratification interface within the physically connected pipe cross section, realizing dynamic isolation between the central gas-rich zone and the peripheral pure zone, thereby allowing degassing analysis of the central flow and dielectric loss measurement of the peripheral flow at the same time.

[0055] The breakdown test unit 300 is located downstream and is used to perform destructive insulation strength tests; the self-healing damping valve 400 cleverly utilizes the fluid shock wave energy generated at the moment of breakdown as the driving force to realize automatic sewage discharge and media renewal without external control, effectively preventing carbonized particles from backflowing and contaminating the upstream precision sensor, and ensuring the continuity and robustness of multi-parameter synchronous detection.

[0056] The stator 111 of the micro screw pump 110 is made of elastomer material, the screw rotor 112 of the micro screw pump 110 is a stainless steel screw, one end of the rigid transition tube 120 is connected to the micro screw pump 110 through the flange 121, and the other end is connected to the borosilicate glass tube 210. The sealing joint 122 is a compression fitting.

[0057] This embodiment is a specific embodiment of the fluid drive unit 100; the micro screw pump 110 is selected as the core power component, and its stator 111 is made of a highly wear-resistant elastomer material, which is matched with a stainless steel screw rotor 112. This structure can realize continuous volumetric delivery of fluid with a micron-level fit gap, eliminating the periodic pressure pulsation common in traditional plunger pumps or peristaltic pumps.

[0058] Because the ultrasonic standing wave field in the acoustic-electric stratification test pipeline 200 has extremely high requirements for flow field stability, any slight pressure fluctuation may disrupt the binding state of the bubble at the acoustic pressure node. The extremely low Reynolds number laminar flow output by the micro screw pump 110 provides the necessary hydraulic basis for establishing a stable acoustic potential well.

[0059] The rigid transition pipe 120 is rigidly connected to the pump body through the flange 121 and sealed with a compression fitting. This fully rigid connection design eliminates the elastic deformation energy storage effect that may be generated by the flexible pipeline, ensuring that the flow command at the pump end can be transmitted to the test pipeline without delay or attenuation, and realizing precise response control of the flow field.

[0060] There are four piezoelectric ceramic transducers 220, which are symmetrically distributed in a cross shape along the circumference of the borosilicate glass tube 210. The interlocking comb-shaped electrodes 230 are wound in a double helix structure along the inner wall of the borosilicate glass tube 210.

[0061] This embodiment is a specific embodiment of the acoustic-electric structure of the acoustic-electric layering test pipeline 200; four piezoelectric ceramic transducers 220 are symmetrically distributed in a cross shape along the circumference of the borosilicate glass tube 210, and interlocking comb-shaped electrodes 230 extend along the axial direction of the borosilicate glass tube 210; the interlocking comb-shaped electrodes 230 are deposited using micro-nano fabrication technology, and their finger width is 50 mm. The finger spacing is 50. The electrode material is an indium tin oxide transparent conductive film, designed to create a high-gradient non-uniform electric field while ensuring light transmittance; based on the radial standing wave theory of cylindrical waveguides, the target driving frequency... The following formula relationship must be satisfied:

[0062] ;

[0063] In the formula, The driving frequency of the piezoelectric ceramic transducer 220 is given in units of... ; Pi; For first-order Bessel functions of the first kind The first zero-point value; The velocity of sound in insulating oil, in units of ; This refers to the inner diameter of the borosilicate glass tube 210. , For example, the fundamental frequency is calculated. ;

[0064] In addition, it can also be used , The frequencies corresponding to higher-order modes excite higher-order concentric ring-shaped standing wave fields; where α02≈7.02 is the first-order Bessel function of the first kind. The second zero-point value, The third zero-point value corresponds to the second and third order nodal circular modes of radial sound pressure distribution inside the pipe, respectively.

[0065] At this frequency, although four discrete piezoelectric ceramic transducers 220 are used, by utilizing the principle of linear superposition of waves, the four sound waves can synthesize an approximately ideal first-order radially symmetrical ultrasonic standing wave in the fluid medium inside the pipe, forming an acoustic pressure antinode and displacement node at the central axis of the pipe, which is the low potential energy point of the acoustic radiation potential energy, thereby stably accumulating microbubbles in the oil with huge differences in acoustic impedance characteristics from the liquid matrix at the center of the pipe.

[0066] Meanwhile, the interlocked comb electrode 230 creates a strong non-uniform electric field on the inner surface of the tube wall. Specifically, it is configured to apply an amplitude of 200Vpp to 500Vpp and a frequency of [missing information] to the interlocked comb electrode 230. to With the AC driving voltage, under these electrical parameters, positive permittivity is used to capture aging product particles and moisture with high polarizability, while negative permittivity is used to repel bubbles. This synergistic effect of acoustic and electric fields not only enhances the migration efficiency of bubbles toward the center, but also simultaneously completes the online purification of the surrounding oil, creating a clean physical environment for high-precision dielectric loss measurement.

[0067] The inner cavity of the hollow permeable fiber membrane tube 240 is connected to the gas inlet of the gas detector, and the annular metal shielding electrode 250 and the conductive medium inside the hollow permeable fiber membrane tube 240 form a coaxial cylindrical capacitor.

[0068] This embodiment is a specific implementation of the structural layout of the detection component; the hollow permeable fiber membrane tube 240 is coaxially suspended inside the downstream of the borosilicate glass tube 210, and its inner cavity is directly connected to the gas chromatograph; since the upstream acoustic radiation force has compressed most of the microbubbles to the gas-rich core flow region near the central axis of the pipeline, this region coincides with the spatial position of the hollow permeable fiber membrane tube 240, which greatly improves the mass transfer efficiency of gas through the membrane wall and realizes efficient online degassing;

[0069] Meanwhile, the annular metal shielding electrode 250 wrapped around the outer wall of the borosilicate glass tube 210 and the conductive medium inside the hollow breathable fiber membrane tube 240 constitute the two plates of the coaxial cylindrical capacitor, and the oil flowing through the annular flow channel 260 between them is the dielectric of the capacitor.

[0070] Since the annular flow channel 260 is located in the purification zone of the acoustic field and electric field, the oil is in a pure state without bubbles and impurities. Therefore, the capacitance value and dielectric loss factor measured by the coaxial capacitor structure can truly reflect the intrinsic insulation characteristics of the insulating oil, avoiding measurement errors caused by the distortion of the electric field by bubbles.

[0071] The bottom of the insulation test chamber 310 is a funnel-shaped structure 330, the drain outlet 340 is located at the lowest point of the funnel-shaped structure 330, and the side of the insulation test chamber 310 is provided with a main outlet 350.

[0072] The straight end of the three-way shunt pipe body 410 is constructed as a sealed blind end. One end of the return spring 440 abuts against the back of the damping piston 430, and the other end abuts against the end cap of the side branch pipe 420.

[0073] Borosilicate glass tube 210 has high sound transmission characteristics, and hollow breathable fiber membrane tube 240 is made of hydrophobic polypropylene material.

[0074] This embodiment is a specific embodiment of the structure of the breakdown test unit 300 and the self-healing damping valve 400; the bottom of the insulation test chamber 310 is designed as a funnel-shaped structure 330, the drain port 340 is located at the lowest point of the funnel-shaped structure 330, and the side of the insulation test chamber 310 is provided with a main outlet 350.

[0075] The straight end of the three-way shunt tube 410 is a sealed blind end. One end of the return spring 440 rests against the back of the damping piston 430, and the other end rests against the end cap of the side branch tube 420. The borosilicate glass tube 210 has high sound transmission characteristics, and the hollow breathable fiber membrane tube 240 is made of hydrophobic polypropylene material.

[0076] With the funnel-shaped structure 330, the principle of gravity settling is used to guide the carbonized particles generated by the breakdown to naturally converge to the sewage channel inlet, preventing them from suspending in the electrode gap and affecting subsequent tests; the self-healing damping valve 400 integrates the damping piston 430 and the return spring 440 in the three-way diversion pipe body 410 side branch pipe 420, and the straight end is normally closed, and the side wall is provided with a pressure relief hole 450.

[0077] For the continuous flow detection function, the main outlet 350 on the side of the insulation test chamber 310 is always connected to the circulation loop as the downstream passage of clean oil. Under normal laminar flow conditions, the hydrostatic pressure of the fluid acting on the bottom drain port 340 is insufficient to overcome the preload of the reset spring 440. The damping piston 430 blocks the pressure relief hole 450, ensuring the sealing of the drain branch without affecting the continuous flow of the main oil circuit.

[0078] Once a breakdown occurs, the energy released instantaneously by the electric arc is converted into a high-pressure fluid shock wave in the incompressible oil. The pressure of this shock wave far exceeds the spring preload, pushing the damping piston 430 backward at high speed. When the piston stroke passes the pressure relief hole 450, the high-pressure deteriorated oil containing carbonized particles is quickly discharged.

[0079] At this time, since the pressure relief hole 450 is connected to the low-pressure atmosphere, the high-pressure oil in the insulation test chamber 310 forms an instantaneous high-speed jet under the action of pressure difference, which forces the carbonized particles deposited at the bottom of the funnel-shaped structure 330 to be flushed out, realizing the mechanism of self-cleaning by using destructive energy itself.

[0080] The borosilicate glass tube 210 is made of a high sound transmittance material to minimize sound energy loss, and the hollow breathable fiber membrane tube 240 is made of hydrophobic polypropylene material. Its surface tension characteristics ensure that only gas molecules can pass through while blocking oil molecules, thus ensuring the dryness and safety of the gas circuit system.

[0081] In a specific parameter configuration, the preload of the return spring 440 is set to... The pressure-bearing area of ​​the damping piston 430 is The corresponding diameter is approximately The back pressure threshold for maintaining a seal is approximately In standard insulating oil breakdown tests, the voltage ranges from 30kV to 80kV, and the discharge energy W is approximately 10J to 50J. Based on the empirical formula for liquid discharge shock waves modified according to the underwater explosion similarity law:

[0082] ;

[0083] in, For peak shock wave pressure, in units ; Discharge energy, unit ; The distance from the discharge center, in units of ;index The power-law relationship characterizes the attenuation of shock wave pressure with increasing distance; coefficients Defined as the dimensionless dielectric shock wave conversion efficiency constant, its physical unit is 1. This is used to balance the physical dimensions on both sides of the formula; in this embodiment, the coefficient... The value was obtained through calibration testing in insulating oil using a standard needle-plate electrode system and a polyvinylidene fluoride shock wave pressure sensor. The calibrated value was then taken as... ;

[0084] At a distance from the discharge center At that location, the peak shock wave pressure was calculated. Approximately to The instantaneous thrust generated by this pressure:

[0085] ;

[0086] in, For instantaneous thrust, unit ; The pressure-bearing area of ​​the damping piston 430 is expressed in units of... Approximately to This value is much greater than the preload of the return spring 440 (15N) and the maximum static friction of the piston (approximately 5N), thus ensuring that the damping piston can be effectively driven and complete the retraction action.

[0087] Example 2:

[0088] Please see Figures 1-6 A rapid synchronous detection method for multiple parameters of insulating oil, comprising:

[0089] S1. Control the fluid drive unit 100 to work at the initial preset speed, push the insulating oil to be tested into the acoustic-electrical stratification test pipeline 200, and establish a laminar background flow field.

[0090] S2. Control the operation of the acoustic-electric stratification test pipeline 200, apply a driving voltage to the piezoelectric ceramic transducer 220 to generate an ultrasonic standing wave field, and apply an alternating electric field to the interlocked comb electrode 230 to generate dielectric force, thereby constructing a central gas-rich core flow and a peripheral pure circulation flow on the pipeline cross-section of the acoustic-electric stratification test pipeline 200.

[0091] S3. Monitor the impedance phase angle of the piezoelectric ceramic transducer 220 in real time, and adjust the rotation speed of the fluid drive unit 100 and the driving voltage amplitude of the piezoelectric ceramic transducer 220 according to the jitter characteristics of the impedance phase angle to maintain the stability of the flow field stratification.

[0092] S4. Gas permeation extraction is performed on the central gas-rich core flow using a hollow permeable fiber membrane tube 240, and the dielectric loss factor of the peripheral pure circulation is measured using an annular metal shielding electrode 250.

[0093] S5. Control the flow of insulating oil into the breakdown test unit 300, and apply voltage across the two hemispherical discharge electrodes 320 to perform insulation performance testing.

[0094] S6. When a breakdown occurs and a fluid shock wave is generated, the shock wave pressure is used to push the damping piston 430 of the self-healing damping valve 400 to compress the return spring 440 and retract.

[0095] S7. When the damping piston 430 retracts to expose the pressure relief hole 450, the deteriorated oil containing carbonized particles is discharged.

[0096] S8. The damping piston 430 is pushed back to reset by the elastic force of the reset spring 440 to reseal the pressure relief hole 450. Under the continuous driving action of the fluid drive unit 100, fresh oil automatically fills the insulation test chamber 310. Steps S1 to S8 are executed in a cycle.

[0097] This embodiment provides a physical field-based method for detecting insulating oil, which deeply integrates fluid mechanics, acoustics, and dielectric physics. The detection process begins with the fluid drive unit 100 establishing a laminar background flow field at an initial preset rotation speed, providing a stable carrier for the controlled migration of microscopic particles.

[0098] When the acoustic-electric stratification test pipeline 200 is started, the ultrasonic standing wave field excited by the piezoelectric ceramic transducer 220 generates an acoustic radiation force pointing towards the center of the pipe, and the non-uniform electric field excited by the interlocked comb electrode 230 generates a dielectric force pointing towards the pipe wall. The two construct a functional zone of central gas-rich core flow and peripheral pure circulation on the cross section of the flowing liquid.

[0099] Under this steady state, the hollow permeable fiber membrane tube 240 permeates and extracts the high-concentration bubble bundle in the center, and the annular metal shielding electrode 250 measures the dielectric loss of the pure oil in the periphery, thus realizing the synchronous acquisition of dynamic and static mutually exclusive parameters.

[0100] When the oil flows to the downstream breakdown test unit 300 for pressure test and breakdown occurs, the generated fluid shock wave pressure directly acts on the self-healing damping valve 400, pushing the damping piston 430 to compress the return spring 440 and retract until the pressure relief hole 450 is exposed to discharge the deteriorated oil.

[0101] After the shock wave dissipates, the reset spring 440 pushes the piston to reset and re-seal the pressure relief hole 450. At this time, the fresh oil continuously pumped in by the upstream fluid drive unit 100 automatically fills the insulation test chamber 310 and the volume gap caused by sewage discharge under the action of the system background pressure, completing the self-healing cycle of the system.

[0102] In step S3, adjusting the rotational speed of the fluid drive unit 100 and the driving voltage amplitude of the piezoelectric ceramic transducer 220 based on the feedback of the jitter characteristics of the impedance phase angle specifically includes:

[0103] Determine whether the jitter amplitude of the impedance phase angle exceeds the preset baseline envelope range;

[0104] If so, it is determined that microbubbles have escaped, and the fluid drive unit 100 is controlled to reduce the speed of the micro screw pump 110 and the acoustic-electric stratification test pipeline 200 is controlled to increase the driving voltage of the piezoelectric ceramic transducer 220.

[0105] This embodiment is a further specification of the acoustic impedance feedback adjustment step; this step introduces a non-invasive flow field monitoring mechanism based on acoustic characteristics, which aims to solve the microbubble escape problem caused by flow velocity fluctuations; the system monitors the impedance phase angle signal of the piezoelectric ceramic transducer 220 in real time, which is extremely sensitive to the distribution of scatterers in the sound field;

[0106] The preset baseline envelope range is determined through self-learning calibration during the initial system startup. Specifically, during the system initialization phase, a pure oil flow is introduced and a sound field is established. Impedance phase angle data over a period of time are collected, and its statistical mean is calculated. and standard deviation Constructing numerical ranges As an absolute safety baseline characterizing the physical stability of the sound field;

[0107] In the logic of adjusting the rotational speed of the fluid drive unit 100 and the driving voltage amplitude of the piezoelectric ceramic transducer 220 based on the jitter characteristics of the impedance phase angle, the following steps are specifically executed: Determine whether the jitter amplitude of the impedance phase angle exceeds the preset baseline envelope range:

[0108] To address potential misjudgments caused by single-point signal noise and to establish a mapping between this judgment step and the specific execution logic, this embodiment employs a statistical judgment method based on energy conservation to determine whether the amplitude exceeds the range: The sliding time window length is set to... For example, containing For each sampling point, the real-time variance of the real-time impedance phase angle within the sliding window is calculated using the following formula:

[0109] ;

[0110] in, represents the real-time variance of the phase angle of the impedance within the sliding window; N is the number of sampling points within the sliding time window. The instantaneous value of the impedance phase angle at the i-th sampling point; The arithmetic mean of N sampling points within the sliding window is used; and the preset baseline envelope range is statistically mapped to a variance threshold.

[0111] ;

[0112] in, This refers to the background standard deviation calculated using the same variance formula as described above, based on the impedance phase angle data collected during the system initialization phase under steady-state pure oil flow. The control algorithm will then use the real-time variance... With variance threshold Perform a comparison, if That is, if the amplitude of the impedance phase angle jitter has exceeded the allowable fluctuation energy boundary of the preset baseline envelope range in terms of statistical distribution characteristics, it is determined that the microbubble has escaped, and the fluid drive unit 100 is controlled to reduce the speed of the micro screw pump 110 and the acoustic-electric stratification test pipeline 200 is controlled to increase the driving voltage of the piezoelectric ceramic transducer 220.

[0113] When the system starts up, the initial drive voltage of the piezoelectric ceramic transducer 220 is set to 50. The specific adjustment adopts the synchronous step approximation method: the adjustment step size involved in this method is a configurable control parameter; in this embodiment, the adjustment period is set. During each adjustment cycle, the speed of the micro-screw pump 110 is reduced to the current set value. ,Right now:

[0114] ;

[0115] in The adjusted target speed, The current rotational speed is used; simultaneously, the driving voltage amplitude of the piezoelectric ceramic transducer 220 is increased by a fixed step. ,like This adjustment action continues to be executed cyclically until the variance is calculated in real time. Falling back to the threshold The following; or the voltage reaches the hardware safety limit, such as This ensures the sound radiation force The growth rate is higher than that of fluid drag force. The fluctuation rate is controlled until the phase angle jitter energy returns to the baseline, thus achieving adaptive maintenance of the flow field stratification state without the need for an optical observation window; Step S5 includes:

[0116] Real-time acquisition of pulse current flowing through the two hemispherical discharge electrodes 320;

[0117] Calculate the time derivative rate of change of the pulse current;

[0118] Determine whether the rate of change of the time derivative exceeds the electron avalanche precursor threshold;

[0119] If so, disconnect the voltage and calculate the breakdown voltage based on the current voltage value, or maintain the voltage to allow breakdown, thereby triggering the self-healing sewage discharge steps S6 to S8.

[0120] This embodiment further specifies the breakdown test procedure; during the application of voltage to the hemispherical discharge electrode 320, the system acquires the microsecond-level pulse current flowing through the electrode with extremely high time resolution; and calculates the time differential rate of change of the pulse current (…). Considering the actual signal noise, the discrete difference method is used for calculation:

[0121] ;

[0122] In the formula, k(t) is the time differential rate of change of the pulse current, in A / s; i(t) is the instantaneous value of the pulse current collected at time t, in A; for The instantaneous value of the pulse current collected at each moment, in A; Δt is the sampling interval, for example, 0.1 μs; Judgment Does it exceed the electron avalanche warning threshold? In this embodiment, the threshold is set based on the flow characteristics of standard transformer oil. to ;

[0123] If so, branch processing is performed according to the current system operating mode: if in non-destructive testing mode, the voltage is cut off and the breakdown voltage is calculated based on the current voltage value; if in self-healing decontamination or system maintenance mode, the voltage is maintained to allow breakdown, thereby triggering the self-healing decontamination steps S6 to S8; wherein, the formula for calculating the breakdown voltage is:

[0124] ;

[0125] In the formula The breakdown voltage is calculated in volts (V). The voltage value at the instant of disconnection; To compensate for voltage; Current change rate, unit A / s; key coefficient It is defined as the equivalent streamer-voltage coupled inductance coefficient;

[0126] It should be noted that, Instead of a physical inductor in a traditional circuit, it is an introduced equivalent circuit modeling parameter based on streamer dynamics, used to characterize the voltage hysteresis response caused by the nonlinear transient impedance characteristics of the streamer channel under high di / dt conditions. Its physical unit is defined as . ,Right now Thus ensuring The result of the calculation is in the voltage unit V;

[0127] The specific acquisition logic and database construction method are as follows: During the calibration stage before the device leaves the factory, multiple complete breakdown tests are conducted using hemispherical electrodes with the same structure as this device; the collected complete breakdown voltage-current waveforms are post-processed and analyzed, and the actual breakdown voltage is recorded. Then, an arbitrary time t before breakdown is selected on the waveform as the assumed cutoff point, and the voltage Ut and the rate of change of current at the i-th sample point are extracted at that time. ; Calculate the streamer-voltage coupling inductance coefficient of the i-th sample point in reverse according to the physical definition. :

[0128] ;

[0129] Collected sample points The set is fitted to a value about using the least squares method. polynomial functions, for example In this embodiment, through quadratic polynomial regression analysis of a large amount of breakdown experimental data, the empirical fitting constant is determined as follows:

[0130] ;

[0131] The dimensions of the above coefficients are set to ensure that when the rate of change of current... (unit Substitute into the fitting formula:

[0132] ;

[0133] It should be understood that the above coefficients , , The specific values ​​are merely calibration examples for a specific hemispherical electrode radius of curvature and a specific electrode spacing in this embodiment; for discharge electrode structures of different sizes or shapes, those skilled in the art should obtain the corresponding fitting coefficients again according to the calibration method disclosed in this specification, and should not limit the scope of protection of this invention to the above specific values;

[0134] Calculated streamer-voltage coupling inductance coefficient It has the correct physical dimensions and units. In actual testing, the system utilizes real-time calculations. Substituting the value into the fitting function directly yields the corresponding result. Value, that The value physically characterizes the equivalent inductive voltage compensation required due to the hysteresis effect of streamer development at the current electron avalanche intensity; through this explicit parameter definition and calibration path, the theoretical breakdown voltage is realized. Accurate calculations are needed to protect the electrode surface from electrolytic corrosion.

[0135] In a specific implementation scenario, the streamer-voltage coupling inductance coefficient λ is not a fixed constant, but rather varies non-linearly with the rate of change of current k. For example, when the system acquires a value of k = 200 mA / μs, a unified conversion to the International System of Units (SI) is required before substituting it into the formula for calculation.

[0136] ;

[0137] Cut off voltage Based on the experimental data, i.e. Cut off voltage ;Will Substitute into the fitting formula:

[0138] ;

[0139] Calculated Therefore, the calibration database was used to obtain the results for this working condition. Substituting into the formula, the compensation voltage is calculated as follows:

[0140] ;

[0141] The predicted breakdown voltage Ub = 38.5 + 8.4 = 46.9 kV; this prediction model effectively compensates for the lag effect of streamer development by introducing a λ coefficient, and can accurately calculate the true breakdown voltage value based on the cutoff voltage.

[0142] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A rapid synchronous detection device for multiple parameters of insulating oil, characterized in that, include: Fluid drive unit (100), acoustic-electric delamination test pipeline (200), breakdown test unit (300), self-healing damping valve (400) and controller; The fluid drive unit (100) is fixed to the base and includes a micro screw pump (110) and a rigid transition pipe (120) connected to its output end. The rigid transition pipe (120) is provided with a sealing joint (122) at its end. The acoustic-electric stratification test pipeline (200) is connected downstream of the fluid drive unit (100). The main body is a borosilicate glass tube (210). A piezoelectric ceramic transducer (220) is bonded to the outer circumference of the borosilicate glass tube (210). A spiral interlocking comb electrode (230) is deposited on the inner wall of the borosilicate glass tube (210). A hollow, breathable fiber membrane tube (240) is coaxially suspended inside the downstream section. A ring-shaped metal shielding electrode (250) is wrapped around the outer wall of the borosilicate glass tube (210) at the corresponding position. The outer diameter of the hollow, breathable fiber membrane tube (240) is smaller than the inner diameter of the borosilicate glass tube (210) to form a ring-shaped flow channel (260). The breakdown test unit (300) is connected to the outlet end of the acoustic-electric delamination test pipeline (200), and includes an insulation test cavity (310) and two hemispherical discharge electrodes (320) arranged opposite to each other inside. The bottom of the insulation test cavity (310) has a drain port (340), and the side of the insulation test cavity (310) has a main outlet (350) that connects to the circulation loop. The self-healing damping valve (400) is connected to the drain port (340) and includes a three-way diversion pipe body (410), a damping piston (430) slidingly mounted in a side branch pipe (420) of the three-way diversion pipe body (410), and a return spring (440) abutting against the back of the damping piston (430). The side branch pipe wall has a pressure relief hole (450). It is configured to open the pressure relief hole (450) and the drain port (340) when the damping piston (430) is pressed back to a predetermined stroke. The controller is connected to the fluid drive unit (100), the acoustic-electric stratification test pipeline (200), the breakdown test unit (300), and the self-healing damping valve (400). The inner cavity of the hollow permeable fiber membrane tube (240) is connected to the gas inlet of the gas detector, and the annular metal shielding electrode (250) and the conductive medium inside the hollow permeable fiber membrane tube (240) constitute a coaxial cylindrical capacitor.

2. The device according to claim 1, characterized in that, The stator (111) of the micro-screw pump (110) is made of elastomeric material, the screw rotor (112) of the micro-screw pump (110) is a stainless steel screw, one end of the rigid transition tube (120) is connected to the micro-screw pump (110) through a flange (121), and the other end is connected to a borosilicate glass tube (210). The sealing joint (122) is a compression fitting.

3. The device according to claim 1, characterized in that, There are four piezoelectric ceramic transducers (220), which are symmetrically distributed in a cross shape along the circumference of the borosilicate glass tube (210), and the interlocking comb-shaped electrodes (230) are wound in a double helix structure along the inner wall of the borosilicate glass tube (210).

4. The device according to claim 1, characterized in that, The bottom of the insulation test chamber (310) is funnel-shaped (330), the drain outlet (340) is located at the lowest point of the funnel-shaped structure (330), and the side of the insulation test chamber (310) is provided with a main outlet (350).

5. The device according to claim 1, characterized in that, The straight end of the three-way shunt pipe body (410) is constructed as a sealed blind end, and one end of the return spring (440) abuts against the back of the damping piston (430), and the other end abuts against the end cap of the side branch pipe (420).

6. The device according to claim 1, characterized in that, The borosilicate glass tube (210) has high sound transmission characteristics, and the hollow breathable fiber membrane tube (240) is made of hydrophobic polypropylene material.

7. The detection method applied to the insulation oil multi-parameter rapid synchronous detection device according to any one of claims 1 to 6, characterized in that, include: S1. Control the fluid drive unit (100) to operate at the initial preset speed, push the insulating oil to be tested into the acoustic-electrical stratification test pipeline (200), and establish a laminar background flow field; S2. Control the operation of the acoustic-electric stratification test pipeline (200), apply a driving voltage to the piezoelectric ceramic transducer (220) to generate an ultrasonic standing wave field, and apply an alternating electric field to the interlocked comb electrode (230) to generate a dielectric force, thereby constructing a central gas-rich core flow and a peripheral pure circulation flow on the pipeline cross section of the acoustic-electric stratification test pipeline (200). S3. Monitor the impedance phase angle of the piezoelectric ceramic transducer (220) in real time, and adjust the rotation speed of the fluid drive unit (100) and the driving voltage amplitude of the piezoelectric ceramic transducer (220) according to the jitter characteristics of the impedance phase angle to maintain the stability of the flow field stratification. S4. Gas permeation extraction of the central gas-rich core flow is performed using a hollow permeable fiber membrane tube (240), and the dielectric loss factor of the peripheral pure circulation is measured using an annular metal shielding electrode (250). S5. Control the flow of insulating oil into the breakdown test unit (300) and apply voltage to both ends of the two hemispherical discharge electrodes (320) to test the insulation performance. S6. When a breakdown occurs and a fluid shock wave is generated, the shock wave pressure is used to push the damping piston (430) of the self-healing damping valve (400) to compress the return spring (440) and retract. S7. When the damping piston (430) retracts to expose the pressure relief hole (450), the deteriorated oil containing carbonized particles is discharged. S8. The damping piston (430) is reset by the elastic force of the reset spring (440) to reseal the pressure relief hole (450). Under the continuous driving action of the fluid drive unit (100), fresh oil automatically fills the insulation test cavity (310). Steps S1 to S8 are executed in a cycle.

8. The detection method according to claim 7, characterized in that, In step S3, adjusting the rotational speed of the fluid drive unit (100) and the driving voltage amplitude of the piezoelectric ceramic transducer (220) based on the feedback of the jitter characteristics of the impedance phase angle specifically includes: Determine whether the jitter amplitude of the impedance phase angle exceeds the preset baseline envelope range; If so, it is determined that microbubbles have escaped, and the fluid drive unit (100) is controlled to reduce the speed of the micro-screw pump (110) and the acoustic-electric stratification test pipeline (200) is controlled to increase the driving voltage of the piezoelectric ceramic transducer (220).

9. The detection method according to claim 7, characterized in that, Step S5 includes: Real-time acquisition of pulse current flowing through the two hemispherical discharge electrodes (320); Calculate the time derivative rate of change of the pulse current; Determine whether the rate of change of the time derivative exceeds the electron avalanche precursor threshold; If so, the voltage is cut off and the breakdown voltage is calculated based on the current voltage value, or the voltage is maintained to allow breakdown, thereby triggering the self-healing sewage discharge steps in steps S6 to S8.

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