A high voltage bushing insulation detection device based on frequency domain dielectric spectrum

Abstract

The application relates to the technical field of insulation detection, and discloses a high-voltage sleeve insulation detection device based on a frequency domain dielectric spectrum, which aims to solve the problem that the internal structure of a host computer is affected by vibration, thereby affecting the precision of high-voltage sleeve insulation detection data. The device is provided with an inner layer shell, an outer layer shell and spring shock absorbers, the inner layer shell is supported at the bottom of the outer layer shell through the four spring shock absorbers, one-stage vibration isolation is achieved, and the air layer between the inner layer shell and the outer layer shell provides viscous damping; when the inner layer shell vibrates, the viscous resistance generated by compressing / stretching air consumes vibration energy, the amplitude is effectively inhibited, and two-stage vibration isolation is achieved.

Description

Technical Field

[0001] This application relates to the field of insulation testing technology, and in particular to a high-voltage bushing insulation testing device based on frequency domain dielectric spectrum. Background Technology

[0002] The frequency domain dielectric spectrum high-voltage bushing insulation testing device is a non-destructive testing device based on dielectric response theory. It is specifically used to evaluate the insulation aging, moisture and defect status of high-voltage bushings (oil-paper insulated type, epoxy-impregnated paper type, etc.) in power systems. It is one of the most advanced insulation diagnostic technologies in the condition-based maintenance of power equipment.

[0003] Existing frequency domain dielectric spectrum high-voltage bushing insulation testing devices, in use, connect the main unit of the testing device to the high-voltage bushing via test leads. The main unit then outputs a low-frequency sinusoidal high voltage (FDS test), and the system automatically sweeps the frequency (10⁻). 4 (~10³Hz), synchronously acquire the amplitude / phase of voltage and current, calculate complex capacitance, complex dielectric constant, and dielectric loss tanδ, and automatically save the spectrum curve after the frequency sweep is completed. Through the above actions, the insulation detection operation of high-voltage bushing is realized.

[0004] However, during the above process, the internal structure of the main unit of the testing device will vibrate during operation. Since the main unit is usually placed on the ground in the testing environment, the vibration will cause the main unit to have low-frequency micro-amplitude intermittent impacts / micro-slippages and collisions with the ground, which will cause slight deformation of the whole machine and slight changes in the relative positions of internal components. This will cause the parasitic capacitance and contact resistance inside the main unit to fluctuate in real time, directly causing dynamic fluctuations in complex capacitance and tanδ dielectric loss value. This will result in problems such as periodic spikes in the measurement curve, large deviations in multiple measurements at the same measurement point, and significant increases in low-frequency noise, thus affecting the accuracy of high-voltage bushing insulation testing data. Summary of the Invention

[0005] This application proposes a high-voltage bushing insulation testing device based on frequency domain dielectric spectrum, which has the advantage of vibration isolation, and is used to solve the problem that the accuracy of high-voltage bushing insulation testing data is affected by vibration of the internal structure of the host.

[0006] To achieve the above objectives, this application adopts the following technical solution: a high-voltage bushing insulation detection device based on frequency domain dielectric spectrum, comprising: an inner shell and a main unit, the main unit being fixedly installed in the inner cavity of the inner shell, the panel of the main unit being disposed at the upper opening of the inner shell, an outer shell being sleeved on the outer side of the inner shell, a cover being hinged to one side of the upper opening of the outer shell, spring dampers being fixedly installed at the four corners of the bottom surface of the inner shell, the lower end of the spring damper being fixedly connected to the bottom inner wall of the outer shell, an extension edge being fixedly installed circumferentially on the side wall of the inner shell, a rubber strip being sleeved on the upper side of the extension edge, and a pressing edge being fixedly installed at the opening of the outer shell, the pressing edge and the extension edge jointly pressing the rubber strip.

[0007] Furthermore, a plug-in housing is sealed and fixedly connected to the lower part of the outer shell. A partition plate is horizontally fixedly installed inside the plug-in housing, dividing the inner cavity of the plug-in housing into a lower air inlet chamber and an upper air outlet chamber. A silent fan is fixedly installed on the side wall of the plug-in housing, and the silent fan connects the external environment to the air inlet chamber. A circular tube assembly is installed at the center of the partition plate and the center of the bottom wall of the outer shell. The air inlet chamber is connected to the inner cavity of the outer shell through the circular tube assembly. A one-way valve is fixedly installed on the bottom wall of the outer shell to discharge the gas inside the outer shell to the air outlet chamber. An air outlet is opened on the side wall of the plug-in housing at the position corresponding to the air outlet chamber. Heating elements and cooling elements are alternately fixedly installed circumferentially inside the circular tube assembly. Spacers are fitted on the outer sides of both the heating elements and the cooling elements, and both ends of the spacers are open.

[0008] Furthermore, a flow guide platform is provided on the bottom surface of the inner shell, corresponding to the position of the upper port of the circular tube assembly. The flow guide platform has a conical structure, with the tip of the conical structure facing the upper port of the circular tube assembly. Flow guide grooves are provided on the side wall of the inner shell and the inner side wall of the outer shell. The cross-sectional area of ​​the flow guide grooves gradually increases from bottom to top. The upper port of the circular tube assembly has a flared structure.

[0009] Furthermore, the outer shell, the plug-in shell, and the circular tube assembly are all made of aluminum alloy, the inner shell and the flow guide are both made of permalloy, and the rubber strip is made of silver-plated aluminum-filled silicone rubber.

[0010] Furthermore, the partition plate has a corrugated plate structure and is made of aluminum alloy.

[0011] Furthermore, there is a distance in centimeters between the upper side of the partition plate and the bottom surface of the outer shell, and the one-way valve and the air outlet are located on both sides of the circular tube assembly.

[0012] Furthermore, the flow guide is rotatably mounted on the bottom surface of the inner shell, and the conical inclined surface of the flow guide is provided with arc-shaped grooves at equal intervals in the circumferential direction.

[0013] Furthermore, the circular tube assembly consists of an upper tube and a lower tube. The lower end of the upper tube is slidably inserted into the bottom wall of the outer shell. A guide sleeve is fixedly installed inside the bottom wall of the outer shell and outside the upper tube. The upper port of the upper tube has a flared structure. The lower tube is fixedly connected to a partition plate. The heating element, cooling element, and partition sleeve are all fixedly installed inside the lower tube. The upper end of the lower tube is inserted into the bottom wall of the outer shell. There is a gap in millimeters between the upper port of the lower tube and the bottom wall of the outer shell. An electric cylinder is fixedly installed on the bottom inner wall of the insertion shell. The telescopic rod of the electric cylinder extends into the upper tube. A magnetic block is provided at the center of the inner side of the upper tube. The magnetic block is fixedly connected to the inner wall of the upper tube through a connecting rod. The end of the telescopic rod of the electric cylinder and the magnetic block are attracted to each other by opposite poles.

[0014] This application has the following beneficial effects: This application provides a high-voltage bushing insulation detection device based on frequency domain dielectric spectrum. Through the arrangement of an inner shell, an outer shell, and spring dampers, the inner shell is supported at the bottom of the outer shell by four spring dampers to achieve primary vibration isolation. The air layer between the inner shell and the outer shell provides viscous damping. When the inner shell vibrates, the viscous resistance generated by the compression / stretching of the air consumes the vibration energy and effectively suppresses the amplitude, thus achieving secondary vibration isolation.

[0015] By using a silent fan, heating element, and cooling element, the silent fan blows outside air into the connector housing. Then, the heating element or cooling element operates according to the ambient temperature, allowing hot or cold air to enter the space between the inner and outer housings. This protects the components inside the inner housing and prevents weather temperature from affecting the accuracy of high-voltage bushing insulation test data. Attached Figure Description

[0016] The accompanying drawings, which form part of this specification, illustrate embodiments disclosed in this application and, together with the specification, serve to explain the principles disclosed in this application.

[0017] This application can be more clearly understood with reference to the accompanying drawings and the following detailed description, wherein: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the outer shell and the plug-in shell of the present invention; Figure 3 This is a schematic diagram of the bottom structure of the inner shell of the present invention; Figure 4 This is a diagram showing the internal structure of the plug-in housing of the present invention; Figure 5This is a schematic diagram of the internal structure of the circular tube assembly of the present invention; Figure 6 This is a schematic diagram showing the relative positions of the heating element and the cooling element in this invention.

[0018] In the diagram: 1. Inner shell; 2. Main unit; 3. Outer shell; 4. Cover; 5. Spring damper; 6. Extension edge; 7. Rubber strip; 8. Pressing edge; 9. Insert shell; 10. Divider plate; 11. Silent fan; 12. Round tube assembly; 120. Upper section tube; 121. Lower section tube; 13. One-way valve; 14. Air outlet; 15. Heating element; 16. Cooling element; 17. Spacer; 18. Flow guide platform; 19. Flow guide groove; 20. Arc groove; 21. Guide sleeve; 22. Electric cylinder; 23. Magnetic block; 24. Connecting rod. Detailed Implementation

[0019] The technical solutions of 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 of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0020] Example 1: Please refer to Figures 1-6 A high-voltage bushing insulation detection device based on frequency domain dielectric spectrum includes an inner shell 1, a main unit 2 fixedly installed in the inner cavity of the inner shell 1, a panel of the main unit 2 set at the upper opening of the inner shell 1, an outer shell 3 sleeved on the outer side of the inner shell 1, a cover 4 hinged to one side of the upper opening of the outer shell 3, spring dampers 5 fixedly installed at the four corners of the bottom surface of the inner shell 1, the lower end of the spring damper 5 fixedly connected to the bottom inner wall of the outer shell 3, an extension edge 6 fixedly installed circumferentially on the side wall of the inner shell 1, a rubber strip 7 sleeved on the upper side of the extension edge 6, and a pressure edge 8 fixedly installed at the opening of the outer shell 3 by bolts, the pressure edge 8 and the extension edge 6 together compress the rubber strip 7.

[0021] During use, connect the interface on the main unit 2 panel to the high-voltage bushing using test leads. Then, the main unit 2 outputs a low-frequency sinusoidal high voltage (FDS test), and the system automatically sweeps the frequency (10⁻). 4 (~10³Hz), synchronously acquire the amplitude / phase of voltage and current, calculate complex capacitance, complex dielectric constant, and dielectric loss tanδ, and automatically save the spectrum curve after the frequency sweep is completed. Through the above actions, the insulation detection operation of high voltage bushing can be realized. During this process, the internal structure of the host 2 will generate inherent vibration. At this time, the inner shell 1 is supported at the bottom of the outer shell 3 by four spring dampers 5 to achieve primary vibration isolation. The air layer between the inner shell 1 and the outer shell 3 provides viscous damping. When the inner shell 1 vibrates, the viscous resistance generated by the compressed / stretched air consumes the vibration energy, effectively suppressing the amplitude and achieving secondary vibration isolation, thereby avoiding the impact on the accuracy of the high-voltage bushing insulation test data. After the test is completed, stop the main unit 2 from running, then disconnect the test wires and close the cover 4.

[0022] Please see Figures 1-6 A plug-in housing 9 is sealed and fixedly connected to the lower part of the outer housing 3. A partition plate 10 is horizontally fixedly installed inside the plug-in housing 9, dividing the inner cavity of the plug-in housing 9 into a lower air intake chamber (the cavity between the partition plate 10 and the bottom inner wall of the plug-in housing 9) and an upper air outlet chamber (the cavity between the partition plate 10 and the bottom surface of the outer housing 3). A silent fan 11 is fixedly installed on the side wall of the plug-in housing 9. The intake end of the silent fan 11 is connected to the external environment, and the exhaust end of the silent fan 11 is connected to the air intake chamber. A circular tube assembly 12 is installed at the center of the partition plate 10 and the center of the bottom wall of the outer housing 3. The air intake chamber is connected to the inner cavity of the outer housing 3 through the circular tube assembly 12. A one-way valve 13 is fixedly installed on the bottom wall of the outer shell 3 to discharge the gas inside the outer shell 3 into the gas outlet chamber. An outlet 14 is provided on the side wall of the shell 9 corresponding to the position of the gas outlet chamber. Heating elements 15 and cooling elements 16 are alternately fixedly installed in the circumferential direction inside the circular tube assembly 12. The heating element 15 is a ceramic heating element and the cooling element 16 is a semiconductor cooling element. A power source for controlling the operation of the heating element 15 and the cooling element 16 is fixedly installed on the outside of the circular tube assembly 12. A spacer 17 is provided on the outside of both the heating element 15 and the cooling element 16. The spacer 17 is connected to the circular tube assembly 12. Both the upper and lower ends of the spacer 17 are open. The spacer 17 is made of aluminum silicate ceramic fiber cotton.

[0023] Before using the main unit 2 (in cold weather, when the internal temperature of the main unit is low, or in hot weather, when the internal temperature of the main unit 2 is high), the heating element 15 or the cooling element 16 is operated according to the ambient temperature. Then, the silent fan 11 is run to blow outside air into the air intake chamber and enters the space between the inner shell 1 and the outer shell 3 through the round tube assembly 12. The air passing through the round tube assembly 12 is heated by the heating element 15 or cooled by the cooling element 16, thereby providing temperature protection for the components inside the inner shell 1 and preventing the weather temperature from affecting the accuracy of the high-voltage bushing insulation test data. When the air pressure in the space between the inner shell 1 and the outer shell 3 increases to a certain value, the one-way valve 13 will open, allowing some of the air in the space to enter the air outlet chamber through the one-way valve 13 and be discharged to the outside environment through the air outlet 14. After the test is completed, stop the operation of the main unit 2, heating element 15 and cooling element 16. Then, disconnect the test wires and close the cover 4. Alumina silicate ceramic fiber cotton has an extremely low thermal conductivity, which can isolate the heating element 15 from the cooling element 16 and reduce heat loss.

[0024] Example 2: Please refer to Figures 1-6 A flow guide platform 18 is provided on the bottom surface of the inner shell 1, which is located directly opposite the upper port of the circular tube assembly 12. The flow guide platform 18 has a conical structure, with the tip of the conical structure facing the upper port of the circular tube assembly 12. Flow guide grooves 19 are provided on the side wall of the inner shell 1 and the inner side wall of the outer shell 3. The cross-sectional area of ​​the flow guide grooves 19 gradually increases from bottom to top. The upper port of the circular tube assembly 12 has a flared structure.

[0025] The flared structure of the circular tube assembly 12 expands the diffusion angle of the temperature-regulating air jet, avoiding the problem of excessively high wind speed in the central area and excessively low wind speed at the edge. After the jet impacts the guide platform 18, it is evenly split 360° and flows upward along the guide groove 19. As the cross-sectional area of ​​the guide groove 19 increases along the flow path, the airflow speed decreases, thereby ensuring that the heat transfer coefficient of the upper and lower surfaces of the inner shell is consistent. At the same time, the guide groove 19 increases the heat transfer area of ​​the inner shell 1, thereby improving the temperature uniformity of the inner shell 1 and completely eliminating the temperature difference between the upper and lower surfaces (if the side wall of the inner shell 1 is a smooth surface). At the center of the bottom surface of the inner shell 1: the airflow directly impacts, the local flow velocity is the fastest, and the heat transfer coefficient is the largest. Lower side of inner shell 1: Airflow velocity decreases, heat transfer coefficient decreases; The upper part of the side of the inner shell 1 (below the extended edge 6): the airflow velocity is further reduced, and there is a large area of ​​backflow dead zone, and the heat transfer coefficient is close to the level of natural convection. The heat transfer coefficients of the top and bottom differ by several times, resulting in extremely fast heat transfer at the bottom and extremely slow heat transfer at the top of the side. In addition, when air flows upward along a smooth sidewall, a velocity boundary layer and a thermal boundary layer that gradually thicken will form on the surface. The thicker the boundary layer, the greater the thermal resistance and the lower the heat transfer coefficient. The flow channel 19 in this application achieves a linear and uniform reduction in flow velocity: According to the fluid continuity equation: m = ρ × v × Achannel, where m is the mass flow rate (constant, determined by the speed of the silent fan 11), ρ is the air density (approximately constant), and Achannel is the cross-sectional area of ​​the guide channel 19. The width of the gradually expanding guide channel 19 increases linearly from bottom to top, so the cross-sectional area increases linearly along the flow path. Combined with the uniform distribution of the total flow rate by several guide channels 19, the linear and uniform reduction of the flow velocity is achieved, completely eliminating the sudden change in flow velocity and the backflow dead zone. Meanwhile, the concave-convex structure of the guide channel 19 continuously interrupts the development of the boundary layer, causing the boundary layer to regenerate in each channel. This avoids the heat transfer deterioration caused by the continuous thickening of the boundary layer in the original structure, thereby increasing the heat transfer coefficient of the upper side and further narrowing the heat transfer gap between the upper and lower parts. In addition, when the temperature-regulating air flows upward along the guide groove 19, a uniform static pressure field is formed in the interlayer between the outer shell 3 and the inner shell 1, which generates an upward buoyancy force on the inner shell 1. This buoyancy force offsets part of the static load of the spring damper 5, reduces the compression of the spring's working point, and enters the linear working range of the spring, thereby improving the frequency stability of the vibration isolation system. At the same time, the uniform static pressure field suppresses the torsional vibration and lateral sway of the inner shell 1, making up for the vibration imbalance problem that may be caused by the four-point support.

[0026] Please see Figures 1-6 The outer shell 3, the plug-in shell 9 and the round tube assembly 12 are all made of 6061-T6 aluminum alloy, the inner shell 1 and the guide platform 18 are both made of 1J85 permalloy, and the rubber strip 7 is made of silver-plated aluminum-filled silicone rubber.

[0027] The outer shell 3 of aluminum alloy suppresses electric fields and high-frequency electromagnetic interference, the inner shell 1 of permalloy (high magnetic permeability) suppresses low-frequency magnetic field interference, and the rubber strip 7 with excellent conductivity ensures shielding continuity. The aforementioned gradually expanding guide groove 19 forms a labyrinthine electromagnetic leakage path, extending the shortest propagation path of electromagnetic waves and improving shielding effectiveness. Simultaneously, the flared structure of the circular tube assembly 12 and the conical guide platform 18 form a coaxial shielding structure, effectively suppressing electromagnetic waves propagating along the axial direction of the circular tube assembly 12. This compensates for the inherent defects of the circular tube assembly 12 as an electromagnetic leakage channel (the electromagnetic leakage of the double-shell structure mainly originates from the gap diffraction of the non-ideal shield and multiple reflections within the cavity; by processing the gradually expanding guide groove 19 on the corresponding walls of the inner shell 1 and the outer shell 3, the originally smooth rectangular interlayer space is transformed into a periodic corrugated structure with alternating concave and convex features, preventing electromagnetic waves from being trapped within the interlayer). If the electromagnetic wave continues to propagate in a straight line, it must be reflected multiple times along the uneven surface of the guide groove 19. Each time it passes through a protruding part of the guide groove 19, the propagation direction of the electromagnetic wave will bend. For electromagnetic waves propagating upward from the bottom of the interlayer, the original propagation path length is equal to the height of the interlayer. However, now the electromagnetic wave must be reflected back and forth along the side wall of the guide groove 19, which increases the effective propagation path length. For low-frequency magnetic fields propagating in the air interlayer, although the permeability of air is very low, multiple reflections will cause the magnetic field lines to continuously cut the metal surface, inducing eddy currents inside the metal, thereby producing attenuation. The longer the propagation path, the more times the magnetic field lines cut the metal surface, the greater the eddy current loss, and the more significant the attenuation. Every time an electromagnetic wave is reflected from a metal surface, some of its energy is absorbed by the metal (because metals have finite electrical conductivity). When an alternating magnetic field passes through a metal shell, it induces a ring-shaped eddy current inside the metal. The reverse magnetic field generated by the eddy current cancels out the incident magnetic field. The size of the eddy current is proportional to the area of ​​the eddy current loop. The concave-convex structure of the guide groove 19 greatly increases the effective area of ​​the metal surface, thereby increasing the area of ​​the eddy current loop. This makes the induced eddy current stronger, the generated reverse magnetic field larger, and the shielding effectiveness higher. In addition, since the width of the guide channel 19 increases linearly from the bottom to the top, it avoids the frequency resonance effect that may occur in a fixed-size channel. If the channel size is fixed, resonance will occur in the channel when the half wavelength of the electromagnetic wave is equal to the channel width, causing the shielding effectiveness to drop sharply. The gradually expanding structure disperses the resonant frequency over a wide frequency band, and no obvious resonance peak will appear in the entire frequency band. In addition, as the air pressure in the aforementioned interlayer space increases, the air pressure will cause the inner shell 1 and the extension edge 6 to squeeze the rubber strip 7, thereby improving the electromagnetic sealing effect of the rubber strip 7.

[0028] Please see Figures 1-6 The partition plate 10 has a corrugated plate structure and is made of 6061-T6 aluminum alloy. There is a gap of centimeters between the upper side of the partition plate 10 and the bottom surface of the outer shell 3. The one-way valve 13 and the air outlet 14 are located on both sides of the circular tube assembly 12.

[0029] During the process of some air entering the air outlet chamber from the one-way valve 13 in the space between the inner shell 1 and the outer shell 3, the heat or cold in the air will be transferred to the partition plate 10. Since the air entering the air inlet chamber by the silent fan 11 will come into contact with the partition plate 10, the air in the air inlet chamber will be preheated or precooled first, so that the heating efficiency or cooling efficiency of the air after entering the interlayer space is higher. Meanwhile, the corrugated plate structure increases the contact area between the air and the partition plate 10, allowing more heat or cold to be transferred to the air in the intake chamber by the partition plate 10, thereby further improving the heating or cooling efficiency of the air.

[0030] Example 3: Please refer to Figures 1-6 The flow guide platform 18 is rotatably mounted on the bottom surface of the inner shell 1, and the conical inclined surface of the flow guide platform 18 is provided with arc-shaped grooves 20 at equal intervals in the circumferential direction.

[0031] When the air in the aforementioned intake chamber enters the interlayer space through the circular tube assembly 12, it blows directly onto the guide platform 18. Since the guide platform 18 has circumferentially equidistant arc-shaped grooves 20 on its conical inclined surface, the direct airflow causes the guide platform 18 to rotate. During this rotation, the guide platform 18 generates minute high-frequency vibrations (the arc-shaped grooves 20 on the conical surface of the guide platform 18 are equivalent to miniature blades; when the airflow passes through, periodic Karman vortex streets are generated at the trailing edge of each groove, simultaneously forming pressure pulsations at the blade passing frequency). These vibrations are then transmitted to the partition plate 10, causing it to undergo minute forced vibrations (the straight-line distance between the guide platform 18 and the partition plate 10 is extremely short, resulting in minimal attenuation of the sound waves; all the vibrational energy is transmitted to the surface of the partition plate 10 through the air). Simultaneously, the interlayer and the exhaust chamber together constitute a… When the vibration frequency of the flow guide 18 coincides with the natural frequency of the cavity, acoustic resonance will occur in the acoustic resonant cavity, amplifying the amplitude of the pressure wave and further enhancing the forced vibration of the partition plate 10. This further disrupts the thermal boundary layer on the outlet side, improving heat transfer efficiency. (The periodic up-and-down vibration of the partition plate 10 will generate a suction-blowing effect on the surface: when the partition plate 10 moves upward, it blows the high-temperature fluid in the boundary layer towards the mainstream area; when the partition plate 10 moves downward, it draws the low-temperature fluid in the mainstream area to the wall. This effect completely breaks the stable existence of the thermal boundary layer. At the same time, the uneven surface of the corrugated partition plate 10 will deflect the microflow field generated by the vibration, forming additional secondary flows at the crests and troughs, further enhancing fluid mixing and thus enhancing the heat transfer effect of the partition plate 10.) Meanwhile, the magnetic domains inside the rotating permalloy conical guide platform 18 continuously flip with the direction of the magnetic field, and the friction between the magnetic domains consumes a large amount of magnetic field energy. For a 50Hz power frequency magnetic field, the hysteresis loss is several times higher than that when it is static. A rotating conductor in an alternating magnetic field will generate an induced electromotive force, thereby forming motional eddy currents. The reverse magnetic field generated by the eddy currents cancels the incident magnetic field, and the Joule heat of the eddy currents consumes the magnetic field energy. The rotating guide platform 18 continuously changes the direction of the electromagnetic leakage path, making it impossible for electromagnetic waves to form a stable propagation path, thereby disrupting the original resonance conditions and avoiding a decrease in shielding effectiveness at a specific frequency. In addition, the rotating conical guide platform 18 is equivalent to a miniature gyroscope, which has the characteristic of conservation of angular momentum. Its angular momentum direction is vertically upward. When the inner shell 1 is subjected to external torsional vibration or lateral oscillation disturbance, the gyroscope effect will generate a reverse restoring torque to counteract the disturbance torque and keep the inner shell stable. The rotating guide platform 18 causes the surrounding air to rotate, generating additional air damping and further dissipating vibration energy. The gyro effect is far more effective than the spring damper 5 in suppressing high-frequency micro-vibrations, while the spring damper 5 is even more effective in suppressing low-frequency vibrations, and the two complement each other.

[0032] Example 4: Please refer to Figures 1-6 The circular tube assembly 12 consists of an upper tube 120 and a lower tube 121. The lower end of the upper tube 120 is slidably inserted into the bottom wall of the outer shell 3. A guide sleeve 21 is fixedly installed inside the bottom wall of the outer shell 3 and outside the upper tube 120. The guide sleeve 21 is made of 25% glass fiber filled polytetrafluoroethylene. The upper end of the upper tube 120 has a flared structure. The lower tube 121 is fixedly connected to the partition plate 10. The heating element 15, the cooling element 16, and the partition sleeve 17 are all fixedly installed inside the lower tube 121. The upper end of the lower tube 121... The lower end is inserted into the bottom wall of the outer shell 3. There is a gap of millimeters between the upper end of the lower section tube 121 and the bottom wall of the outer shell 3. An electric cylinder 22 is fixedly installed on the bottom inner wall of the insertion shell 9. The telescopic rod of the electric cylinder 22 passes through the lower section tube 121 and extends into the upper section tube 120. A magnetic block 23 is provided at the center of the inner side of the upper section tube 120. The magnetic block 23 is fixedly connected to the inner wall of the upper section tube 120 through the connecting rod 24. The end of the telescopic rod of the electric cylinder 22 and the magnetic block 23 are set to attract each other with opposite poles.

[0033] The air in the aforementioned intake chamber passes through the lower section pipe 121 and the upper section pipe 120 in sequence, and then enters the interlayer space. During this process, the electric cylinder 22 operates, causing the telescopic rod to drive the magnetic block 23, the connecting rod 24 and the upper section pipe 120 to move up and down repeatedly, so that the flared mouth of the upper section pipe 120 intermittently approaches the guide platform 18 (but does not contact it). Through this action, the air discharged from the flared mouth of the upper section pipe 120 forms a pulse jet. The pulsating jet impacts the surface of the conical guide platform 18, and forms a pulsating-rotational dual fluid effect with the rotation of the guide platform 18. The shearing force of the pulsating jet makes the rotation of the guide platform 18 more stable. The rotating guide platform 18 generates dynamic hysteresis loss, while the reciprocating upper section tube 120 generates dynamic eddy current loss. (The permeability of the 1J85 permalloy of the inner shell 1 is 120,000 times that of air. Low-frequency magnetic fields incident from the outside (such as a 50Hz power frequency magnetic field) will be completely "absorbed" into the permalloy shell like water encountering a sponge, flowing along a closed magnetic circuit. This results in a stronger magnetic field closer to the permalloy surface and an exponentially decreasing magnetic field with increasing distance. The upper section tube 120 is made of 6061-T6 aluminum alloy with a conductivity σ≈3.77×10⁻⁶.) 7S / m, containing a massive number of free electrons. Simultaneously, since the upper tube 120 is a complete cylindrical closed conductor, any induced electromotive force will form a continuous loop current within the tube wall. When the upper tube 120 moves upwards, its upper end will gradually move from a region with a weaker magnetic field (near the outer shell 3) to a region with a stronger magnetic field (near the current guide platform 18). According to Faraday's law of electromagnetic induction, when a conductor moves in a magnetic field, the free electrons inside will experience a Lorentz force. This force will push the free electrons within the tube wall to move in a clockwise direction. The upper tube 120 is a closed cylindrical conductor. The free electrons moving in a specific direction will form countless coaxial ring eddy currents inside the tube wall. The path of the eddy currents is perpendicular to the direction of the magnetic field and the direction of motion. When the eddy currents flow in the aluminum alloy tube wall with resistance, they will generate Joule heat, converting the energy of the magnetic field into heat energy and dissipating it into the air (this is dynamic eddy current loss). The two superimposed form a rotating-reciprocating dual dynamic magnetic shield. For a 50Hz power frequency magnetic field, the hysteresis loss is increased, the eddy current loss is increased, and the overall shielding effectiveness is improved, thereby making up for the deficiency of single dynamic shielding in suppressing ultra-low frequency magnetic fields. After the pulsating airflow enters the gradually expanding guide channel 19, it generates periodic pressure waves and velocity waves along the way, which resonate with the gradually expanding structure of the guide channel 19 to enhance the effect: the pulsating airflow will generate a suction-blowing effect, which will completely destroy the boundary layer multiple times per second, keeping the boundary layer thickness below 0.2mm and improving the overall heat transfer coefficient of the sidewall. The pulsating airflow causes the air density in the interlayer to change periodically, which in turn causes the refractive index of the electromagnetic wave propagation medium to change periodically, thus generating additional scattering loss. Meanwhile, the periodically changing pressure causes the inner shell 1 and the outer shell 3 to undergo slight elastic deformation, which further increases the randomness of the electromagnetic leakage path, thereby improving the shielding effectiveness and making up for the deficiency of the fixed labyrinth structure in suppressing coherent electromagnetic waves.

Claims

1. A high-voltage bushing insulation testing device based on frequency domain dielectric spectrum, comprising: The inner shell (1) and the main unit (2) are fixedly installed in the inner cavity of the inner shell (1). The panel of the main unit (2) is set at the upper opening of the inner shell (1). The outer shell (3) is sleeved on the outer side of the inner shell (1). A cover (4) is hinged to one side of the upper opening of the outer shell (3). The inner shell (1) is characterized in that spring dampers (5) are fixedly installed at the four corners of the bottom surface of the inner shell (1). The lower end of the spring damper (5) is fixedly connected to the bottom inner wall of the outer shell (3). An extension edge (6) is fixedly installed on the side wall of the inner shell (1). A rubber strip (7) is sleeved on the upper side of the extension edge (6). A pressing edge (8) is fixedly installed at the opening of the outer shell (3). The pressing edge (8) and the extension edge (6) together squeeze the rubber strip (7).

2. The high-voltage bushing insulation testing device based on frequency domain dielectric spectrum according to claim 1, characterized in that, A plug-in housing (9) is sealed and fixedly connected to the lower part of the outer shell (3). A partition plate (10) is horizontally fixedly installed inside the plug-in housing (9). The partition plate (10) divides the inner cavity of the plug-in housing (9) into a lower air intake chamber and an upper air outlet chamber. A silent fan (11) is fixedly installed on the side wall of the plug-in housing (9). The silent fan (11) connects the external environment with the air intake chamber. A circular tube assembly (12) is installed at the center of the partition plate (10) and at the center of the bottom wall of the outer shell (3). The air intake chamber is connected to the circular tube. The component (12) is connected to the inner cavity of the outer shell (3). A one-way valve (13) is fixedly installed on the bottom wall of the outer shell (3) to discharge the gas in the outer shell (3) to the outlet chamber. An outlet (14) is opened on the side wall of the plug-in shell (9) at the position corresponding to the outlet chamber. A heating element (15) and a cooling element (16) are alternately fixedly installed in the inner circumference of the round tube component (12). A spacer (17) is sleeved on the outer side of both the heating element (15) and the cooling element (16). Both the upper and lower ends of the spacer (17) are open.

3. The high-voltage bushing insulation testing device based on frequency domain dielectric spectrum according to claim 2, characterized in that, A flow guide platform (18) is provided on the bottom surface of the inner shell (1) and at the position corresponding to the upper port of the circular tube assembly (12). The flow guide platform (18) is a conical structure with the tip of the conical structure facing the upper port of the circular tube assembly (12). Flow guide grooves (19) are provided on the side wall of the inner shell (1) and the inner side wall of the outer shell (3). The cross-sectional area of ​​the flow guide grooves (19) gradually increases from bottom to top. The upper port of the circular tube assembly (12) is a flared structure.

4. The high-voltage bushing insulation testing device based on frequency domain dielectric spectrum according to claim 3, characterized in that, The outer shell (3), the plug-in shell (9) and the round tube assembly (12) are all made of aluminum alloy, the inner shell (1) and the guide platform (18) are both made of permalloy, and the rubber strip (7) is made of silver-plated aluminum-filled silicone rubber.

5. The high-voltage bushing insulation testing device based on frequency domain dielectric spectrum according to claim 2, characterized in that, The partition plate (10) is a corrugated plate structure and is made of aluminum alloy.

6. The high-voltage bushing insulation testing device based on frequency domain dielectric spectrum according to claim 5, characterized in that, The upper side of the partition plate (10) and the bottom surface of the outer shell (3) are spaced in centimeters apart, and the one-way valve (13) and the air outlet (14) are located on both sides of the circular tube assembly (12).

7. The high-voltage bushing insulation testing device based on frequency domain dielectric spectrum according to claim 3, characterized in that, The flow guide platform (18) is rotatably mounted on the bottom surface of the inner shell (1), and the conical inclined surface of the flow guide platform (18) is provided with arc-shaped grooves (20) at equal intervals in the circumferential direction.

8. The high-voltage bushing insulation testing device based on frequency domain dielectric spectrum according to claim 7, characterized in that, The circular tube assembly (12) consists of an upper tube (120) and a lower tube (121). The lower end of the upper tube (120) is slidably inserted into the bottom wall of the outer shell (3). A guide sleeve (21) is fixedly installed inside the bottom wall of the outer shell (3) and outside the upper tube (120). The upper end of the upper tube (120) has a flared structure. The lower tube (121) is fixedly connected to the partition plate (10). The heating element (15), cooling element (16), and partition sleeve (17) are all fixedly installed inside the lower tube (121). The upper end of the lower tube (121) is inserted into the outer shell. The bottom wall of the outer shell (3) has a gap in millimeters between the upper port of the lower section tube (121) and the bottom wall of the outer shell (3). An electric cylinder (22) is fixedly installed on the bottom inner wall of the plug-in shell (9). The telescopic rod of the electric cylinder (22) extends into the upper section tube (120). A magnetic block (23) is provided at the center of the inner side of the upper section tube (120). The magnetic block (23) is fixedly connected to the inner wall of the upper section tube (120) through the connecting rod (24). The end of the telescopic rod of the electric cylinder (22) and the magnetic block (23) are set to attract each other with opposite poles.

Images