Electrical tree in-situ growth observation device based on low-temperature objective lens

Abstract

The invention relates to the technical field of insulating material electrical tree growth observation devices, and provides an electrical tree in-situ growth observation device based on a low-temperature objective lens, and the device comprises a low-temperature thermostat which is used for providing a low-temperature constant-temperature environment; the high-voltage discharge sample cavity is communicated with the low-temperature thermostat, a sample is arranged in the high-voltage discharge sample cavity, and the high-voltage discharge sample cavity is connected with a high-voltage electrode and a ground electrode; the low-temperature objective lens in-situ observation assembly is communicated with the high-voltage discharge sample cavity, and the low-temperature objective lens in-situ observation assembly is used for observing the electrical tree in-situ growth process of the sample. According to the electrical tree in-situ growth observation device based on the low-temperature objective lens, an electrical tree growth platform with a wide temperature range of 40K-300K can be provided, and fine in-situ observation of an electrical tree dendronization process is realized; the low-temperature thermostat adopts a helium exchange heat exchange scheme to realize thermal mechanical isolation, so that the use of low-temperature liquid is reduced, the service life of the device is prolonged, and the cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of an insulating material electric tree growth observation device, and in particular to an electric tree in-situ growth observation device based on a low-temperature objective lens. Background Art

[0002] The commonly used insulating material for superconducting magnets is impregnated epoxy resin. When the superconducting magnet is in operation, the epoxy resin needs to experience extreme conditions such as low temperature (<120K), vacuum (<0.1pa) and strong electromagnetic field (>5T), and its voltage resistance will be greatly tested. The electrical tree growth characteristics of epoxy resin at low temperature are a long-term aging characteristic. Detailed research on the law of electrical tree growth, including tree starting voltage and tree shape, can provide a high reference value for engineering applications. The growth law of electrical tree is mainly reflected in the fractal characteristics of its growth process.

[0003] In the prior art, most of the research on electrical tree testing of insulating materials is concentrated at room temperature, while the research at low temperature lacks sophisticated in-situ observation equipment. Precise in-situ observation requires close proximity to the sample surface, but the existence of a vacuum chamber limits this requirement. Summary of the invention

[0004] The present invention provides an in-situ growth observation device for electric tree branches based on a low-temperature objective lens, which is used to solve the defect that the in-situ observation cannot be carried out precisely and needs to be close to the sample surface in the prior art, and realizes the precise in-situ observation of the electric tree branch process of the insulating material.

[0005] The present invention provides an in-situ growth observation device for electric tree dendrites based on a low-temperature objective lens, comprising: A cryostat, used to provide a low temperature constant temperature environment; A high-voltage discharge sample chamber is connected to the low-temperature thermostat, the high-voltage discharge sample chamber has a sample built in it, and the high-voltage discharge sample chamber is connected to a high-voltage electrode and a ground electrode; The low-temperature objective lens in-situ observation component is communicated with the high-voltage discharge sample chamber, and the low-temperature objective lens in-situ observation component is used to observe the in-situ growth process of the electrical dendrites of the sample.

[0006] According to the present invention, a device for observing in-situ growth of electrical dendrites based on a cryogenic objective lens is provided, wherein the cryostat comprises: GM refrigerator, mounted on a bracket; a first vacuum cover, through which the GM refrigerator passes, and the first vacuum cover provides a vacuum environment for the GM refrigerator; A primary cold shield is disposed in the first vacuum cover, and the primary cold shield transfers cold energy through a primary cold head; A cold head heat exchanger, arranged at the end of the GM refrigerator; A secondary helium heat exchange chamber is arranged in the first vacuum cover, and the interior of the secondary helium heat exchange chamber contains helium, and the cold energy of the GM refrigerator is transferred to the helium through the cold head heat exchanger; A cooling stage is arranged at the bottom of the secondary helium heat exchange chamber; A cold finger passes through the first vacuum cover, and the other end of the cold finger extends to the high-voltage discharge sample chamber; and one end of the cold finger located in the high-voltage discharge sample chamber carries the sample.

[0007] According to the in-situ growth observation device for electrical dendrites based on a low-temperature objective lens provided by the present invention, the GM refrigerator and the first vacuum cover are connected by a welded bellows.

[0008] According to the present invention, an in-situ growth observation device for electric tree branches based on a low-temperature objective lens also includes a mounting platform, on which the bracket, the first vacuum cover and the high-voltage discharge sample chamber are arranged; and an air floating shock absorber is arranged between the bracket and the mounting platform.

[0009] According to an in-situ growth observation device for electric tree dendrites based on a low-temperature objective lens provided by the present invention, the high-voltage discharge sample chamber comprises: A ceramic high-voltage sleeve is connected to a high-voltage electrode and a ground electrode via a KF25 interface; the ceramic high-voltage sleeve is used to isolate a vacuum; a second vacuum cover, wherein the cold finger extends into the second vacuum cover; and the second vacuum cover is connected to the first vacuum cover via a KF40 interface to conduct vacuum between the two; An objective lens cavity connected to the top of the second vacuum cover; The transition cavity is arranged at the top of the objective lens cavity, and the transition cavity is used to connect the low-temperature objective lens in-situ observation component.

[0010] According to the in-situ growth observation device of electrical tree based on low-temperature objective lens provided by the present invention, the high-voltage discharge sample chamber further comprises: The visualization quartz window is tilted on the side of the objective lens cavity.

[0011] According to the present invention, a device for observing in-situ growth of electrical dendrites based on a cryogenic objective lens is provided, wherein the cryogenic objective lens in-situ observation component comprises: Three-dimensional displacement slide, with built-in reduction screw; Camera, for taking pictures; An objective lens barrel is arranged at the bottom of the camera, and the top of the objective lens barrel is sealed by quartz glass; and the objective lens barrel is arranged on the three-dimensional displacement slide; A connecting tube, one end of which is connected to the objective lens barrel; The objective lens is connected to one end of the connecting tube which is away from the objective lens barrel; and the connecting tube extends into the transition cavity.

[0012] According to the in-situ growth observation device for electrical dendrites based on a cryogenic objective lens provided by the present invention, the connecting tube is a flexible bellows.

[0013] According to the invention, a low-temperature objective lens-based in-situ observation device for electric tree growth is provided. The low-temperature objective lens in-situ observation assembly further includes a spectroscope, which is arranged on the objective lens barrel and is used to provide visible light intensity.

[0014] According to the in-situ growth observation device for electrical tree dendrites based on a low-temperature objective lens provided by the present invention, the first vacuum cover is made of 304 stainless steel, and the interlayer is made of a high-vacuum multi-layer insulation material.

[0015] The present invention provides an in-situ growth observation device for electric tree dendrites based on a low-temperature objective lens. A low-temperature constant temperature environment is provided by a low-temperature thermostat. A high-voltage discharge sample cavity is connected to the low-temperature thermostat, and a sample is built in the high-voltage discharge sample cavity. An in-situ observation component of the low-temperature objective lens is connected to the high-voltage discharge sample cavity. The low-temperature objective lens can observe the in-situ production process of electric tree dendrites of the sample, so as to provide an electric tree dendrite growth platform in a wide temperature range of 40K-300K, and realize fine in-situ observation of the electric tree dendrite process.

[0016] The cryostat uses helium gas heat exchange to achieve thermal mechanical isolation, reducing the use of cryogenic liquids to increase the service life of the device and reduce costs.

[0017] In addition, strict temperature control by the low-temperature thermostat and strict high-voltage control of the high-voltage discharge sample chamber can prevent the occurrence of Parsing discharge between high and low voltages. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a structural schematic diagram of an electric tree in-situ growth observation device based on a low-temperature objective lens provided by the present invention.

[0020] Figure 2 It is a top view of the in-situ growth observation device of electrical dendrites based on a low-temperature objective lens provided by the present invention.

[0021] Figure 3 yes Figure 2 Middle AA section view.

[0022] Reference numerals: 1. Low temperature thermostat; 2. High voltage discharge sample chamber; 3. Low temperature objective lens in-situ observation assembly; 4. Mounting platform; 5. Air floating shock absorber; 11. GM refrigerator; 12. Bracket; 13. Cold finger; 14. First vacuum cover; 15. First level cold screen; 16. First level cold head; 17. Cold head heat exchanger; 18. Second level helium heat exchange chamber; 19. Cooling stage; 21. Second vacuum cover; 22. Objective lens chamber; 23. Transition chamber; 24. Visualization quartz window; 31. Three-dimensional displacement slide; 32. Camera; 33. Objective lens tube; 34. Connecting tube; 35. Objective lens; 36. Spectroscope. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0025] Combine the following Figure 1-Figure 3 The invention describes an in-situ growth observation device for electrical dendrites based on a cryogenic objective lens.

[0026] like Figure 1 As shown, the in-situ growth observation device for electric tree dendrites based on a cryogenic objective lens provided by an embodiment of the present invention comprises a cryostat 1 , a high-voltage discharge sample chamber 2 and a cryogenic objective lens in-situ observation assembly 3 .

[0027] The cryostat 1 is used to provide a cryostat environment, which can accurately control the low temperature environment required for the experiment; the high-voltage discharge sample chamber 2 is connected to the cryostat 1, the high-voltage discharge sample chamber 2 has a sample built in it, and the high-voltage discharge sample chamber 2 is connected to the high-voltage electrode and the ground electrode, and the high-voltage discharge sample chamber 2 provides a high-voltage environment for the sample, which can simulate the high-voltage discharge conditions in the actual electric field. The cryostat in-situ observation assembly 3 is connected to the high-voltage discharge sample chamber 2, and the cryostat in-situ observation assembly 3 is used to observe the in-situ growth process of the electrical dendrites of the sample. The cryostat in-situ observation assembly 3 can directly observe the growth process of the electrical dendrites without destroying the sample.

[0028] The device for observing the in-situ growth of electric dendrites with a low-temperature objective lens provided by the present invention provides a low-temperature constant temperature environment through a low-temperature thermostat, and a high-voltage discharge sample chamber simulates a high-voltage environment for a sample. The low-temperature objective lens can observe the in-situ growth process of electric dendrites of the sample, so as to provide an electric dendrite growth platform in a wide temperature range of 40K-300K, and realize fine in-situ observation of the electric dendrite process.

[0029] like Figure 2 and Figure 3 As shown, in a feasible embodiment of the present invention, the cryostat 1 includes a GM refrigerator 11, a first vacuum cover 14, a first-stage cold shield 15, a first-stage cold head 16, a cold head heat exchanger 17, a second-stage helium heat exchange chamber 18, a cooling stage 19 and a cold finger 13.

[0030] The GM refrigerator 11 is arranged on the bracket 12. The GM refrigerator can completely overcome the consumption problem of cryogenic liquid, and can make the device run continuously at the set temperature point for dozens of hours. However, the use of the GM refrigerator 11 also introduces the vibration problem. The vibration of the GM refrigerator 11 is about 25μm. In order to overcome this problem, the cold head-test component is isolated by exchanging helium heat.

[0031] Specifically, the first vacuum cover 14 is passed through by the GM refrigerator 11, and the first vacuum cover 14 provides a vacuum environment for the GM refrigerator 11, reducing the potential influence of external air molecules on the experimental process, and improving the accuracy and reliability of the experiment. The first-level cold shield 15 is arranged in the first vacuum cover 14, and the first-level cold shield transfers cold energy through the first-level cold head 16. The cold head heat exchanger 17 is arranged at the end of the GM refrigerator 11; the second-level helium heat exchange chamber 18 is arranged in the first vacuum cover 14, and the second-level helium heat exchange chamber 18 contains helium, and the cold energy of the GM refrigerator 11 is transferred to helium through the cold head heat exchanger 17. The cold conduction cold stage 19 is arranged at the bottom of the second-level helium heat exchange chamber 18; the cold finger 13 passes through the first vacuum cover 14, and the other end of the cold finger 13 extends to the high-voltage discharge sample chamber 2; and the cold finger 13 is located at one end of the high-voltage discharge sample chamber 2 and carries the sample.

[0032] The first vacuum cover 14 is made of 304 stainless steel, and the interlayer is made of high vacuum multi-layer insulation material.

[0033] The working process is as follows: the cold energy of the GM refrigerator 11 is transferred to the helium by the cold head heat exchanger 17, and the helium then transfers the cold energy to the cooling stage 19. After being heated by the cooling stage 19, the temperature of the helium rises and the density decreases, and then after floating, the cold head heat exchanger 17 absorbs heat, the temperature drops, the density increases, and then sinks. This repeated process realizes the exchange of helium heat exchange, and at the same time realizes the complete vibration isolation of the first-level cold head 16 of the refrigerator and the cooling stage 19. The cooling of the sample depends on the cooling stage 19 and the cold finger 13, and the sample stage is installed on the cold finger 13. The cold finger 13 is an oxygen-free copper rod with a diameter of 10mm and a length of 250mm, which has a high efficiency of heat transfer. The first-level cold shield 15 transfers cold energy from the first-level cold head 16 of the refrigerator through the upper flange to realize the radiation heat leakage control of the entire second-level helium heat exchange cavity 18.

[0034] In order to further reduce vibration, in a feasible embodiment of the present invention, the GM refrigerator 11 and the first vacuum cover 14 are connected by a welded bellows, which can control the vibration to a nanometer level.

[0035] In a feasible embodiment of the present invention, it also includes a mounting platform 4, on which a bracket 12, a first vacuum cover 14 and a high-voltage discharge sample chamber 2 are arranged; the mounting platform 4 is a stable foundation for the entire system. An air-floating shock absorber 5 is arranged between the bracket 12 and the mounting platform 4, and the shock absorption and vibration isolation characteristics of the air-floating technology are utilized to effectively reduce the mechanical vibration interference that may be generated during the experiment, further improve the accuracy and stability of the experiment, and also provide a strong guarantee for long-term and continuous experimental observation.

[0036] The above embodiment not only optimizes the layout and structure of the entire observation system, but also significantly improves the accuracy and stability of the experiment by introducing the installation platform 4.

[0037] In a feasible embodiment of the present invention, the high-voltage discharge sample chamber 2 includes a ceramic high-voltage sleeve, a second vacuum cover 21, an objective lens chamber 22 and a transition chamber 23. The ceramic high-voltage sleeve is connected to the high-voltage electrode and the ground electrode through a KF25 interface; the ceramic high-voltage sleeve ensures that the high-voltage electric field is stably distributed in the sample chamber. In addition, the ceramic material has excellent insulation performance and high temperature and high voltage resistance, which can effectively isolate the vacuum environment, prevent electric field leakage, and ensure the safety and accuracy of the experiment.

[0038] The cold finger 13 extends into the second vacuum cover 21, which helps to control the temperature of the sample more accurately. The second vacuum cover 21 is connected to the first vacuum cover 14 through a KF40 interface to conduct the vacuum of the two. The objective lens cavity 22 is connected to the top of the second vacuum cover 21, providing a convenient channel for optical observation. The experimenter can observe the sample in situ through the objective lens and obtain images and data during the experiment in real time. The transition cavity 23 is arranged at the top of the objective lens cavity 22, and the transition cavity 23 is used to connect the low-temperature objective lens in-situ observation component 3. The transition cavity 23 serves as a connection and transition, so that the low-temperature objective lens can be smoothly installed and observed with the sample in the sample cavity.

[0039] In the above embodiments, the structural setting of the high-voltage discharge sample chamber 2 brings multiple beneficial effects such as high-voltage isolation and stability, vacuum environment maintenance, convenient optical observation, compact structure, connection and transition effects, etc., which improves the accuracy and reliability of the experiment and provides strong support for research in the field of in-situ production observation of electrical tree dendrites.

[0040] In a feasible embodiment of the present invention, the high-voltage discharge sample chamber 2 further includes a visualization quartz window 24, which is tiltedly disposed on the side of the objective lens chamber 22 to facilitate experimental observation and adjustment of the low-temperature objective lens.

[0041] In a feasible embodiment of the present invention, the low-temperature objective lens in-situ observation assembly 3 includes a three-dimensional displacement slide 31, a camera 32, an objective lens barrel 33, a connecting tube 34 and an objective lens 35. The three-dimensional displacement slide 31 has a built-in reduction screw, and the displacement can be controlled at nanometer level precision through the reduction screw. The camera 32 is used to take pictures. The camera 32 has a high-resolution imaging capability and can capture subtle changes in the growth of electrical dendrites. The top of the objective lens barrel 33 is sealed by quartz glass; and the objective lens barrel 33 is set on the three-dimensional displacement slide 31; one end of the connecting tube 34 is connected to the objective lens barrel 33; the objective lens 35 is connected to the end of the connecting tube 34 facing away from the objective lens barrel 33; and the connecting tube 34 extends into the transition cavity 23.

[0042] Specifically, the camera is a CCD camera. In the above embodiment, the focusing method is: first, coarse adjustment. The three-dimensional displacement slide 31 connected by the bellows realizes the coarse adjustment of the objective lens 35 observation. By manually adjusting the knob of the three-dimensional displacement slide 31, the coarse adjustment is completed after the CCD camera presents a linear image outline; secondly, fine adjustment. After the image outline appears, the three-dimensional displacement slide 31 is slowly adjusted by the program, and the fine adjustment is completed after the image is clear. The entire objective lens 35 focusing is realized by the flexible connection of the bellows. The low-temperature objective lens is connected to the secondary cold screen by a copper conductive cold belt for cooling, thereby realizing in-situ observation at low temperature, which can overcome the problem of light path radiation noise at room temperature. The objective lens barrel 33 made of 304 stainless steel is responsible for connecting the objective lens 35, and its upper part is sealed by quartz glass. There is a flexible bellows between the bottom of the objective lens barrel 33 and the transition cavity 23, which can realize the movement of the objective lens 35 with the three-dimensional displacement slide 31. The top is a CCD camera and a beam splitter 36, which are responsible for capturing the image of electrical tree aging and providing visible light intensity.

[0043] The beam splitter 36 is disposed on the objective lens tube 33 and is used to provide visible light intensity.

[0044] The working process of the low-temperature objective lens in-situ observation device for electrical tree growth provided by the present invention is as follows: when performing an electrical tree aging observation experiment, firstly, the system is evacuated, the circuit connection is complete, then a proper amount of helium is introduced into the secondary helium heat exchange chamber 18, and then the GM refrigerator 11 is turned on for cooling and the temperature controller is turned on until the target temperature is stable, and finally the light source of the spectroscope 36 and the CCD camera are turned on to capture the electrical tree growth picture at low temperature in real time, and the growth of electrical tree of insulating materials can be carried out in the 77K or lower temperature zone; the low-temperature objective lens in-situ observation component 3 can provide in-situ observation of electrical tree growth at low temperature; the low vibration of the low-temperature thermostat 1 can reduce the observation error of the objective lens 35; the cold head-sample isolation is carried out by exchanging helium for heat exchange, and the vibration can be controlled at the nanometer level.

[0045] In summary, the low-temperature objective lens provided by the present invention is used for the in-situ observation device of the growth of electrical dendrites, the GM refrigerator realizes continuous dry cooling without liquid helium, and the experimental device is installed in a low-temperature thermostat with bellows and air-floating vibration damper for vibration reduction, a temperature controller is used to achieve low-temperature conditions with high-precision temperature control in a wide temperature range, and a scheme of exchanging helium for heat exchange is adopted to realize thermal mechanical isolation. The key point is to assemble and use the low-temperature objective lens to overcome the technical difficulties of body-attached observation, thereby forming a complete in-situ observation system for the growth process of electrical dendrites of insulating materials that integrates high voltage, low temperature and vacuum.

[0046] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0047] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "mode", "specific mode", or "some modes" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or mode are included in at least one embodiment or mode of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or mode. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or modes in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or modes described in this specification and the features of the different embodiments or modes, without contradiction.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for observing the in-situ growth of electrical dendrites based on a cryogenic objective lens, characterized in that: include: A cryostat (1) for providing a cryostatic environment; A high-voltage discharge sample chamber (2) is connected to the low-temperature thermostat (1), the high-voltage discharge sample chamber (2) contains a sample, and the high-voltage discharge sample chamber (2) is connected to a high-voltage electrode and a ground electrode; The low-temperature objective lens in-situ observation component (3) is connected to the high-voltage discharge sample chamber (2), and the low-temperature objective lens in-situ observation component (3) is used to observe the in-situ growth process of electrical dendrites of the sample.

2. The in-situ growth observation device for electrical tree dendrites based on a cryogenic objective lens according to claim 1, characterized in that: The cryostat (1) comprises: A GM refrigerator (11) is arranged on a bracket (12); A first vacuum cover (14) for the GM refrigerator (11) to pass through, and the first vacuum cover (14) provides a vacuum environment for the GM refrigerator (11); A primary cold shield (15) is arranged in the first vacuum cover (14), and the primary cold shield transfers cold energy through a primary cold head (16); A cold head heat exchanger (17) is arranged at an end of the GM refrigerator (11); A secondary helium heat exchange chamber (18) is arranged in the first vacuum cover (14), and the secondary helium heat exchange chamber (18) contains helium, and the cold energy of the GM refrigerator (11) is transferred to the helium through the cold head heat exchanger (17); A cooling stage (19) is arranged at the bottom of the secondary helium heat exchange chamber (18); A cold finger (13) passes through the first vacuum cover (14), and the other end of the cold finger (13) extends to the high-voltage discharge sample chamber (2); and the cold finger (13) is located at one end of the high-voltage discharge sample chamber (2) and carries the sample.

3. The in-situ growth observation device for electrical tree dendrites based on a cryogenic objective lens according to claim 2, characterized in that: The GM refrigerator (11) and the first vacuum cover (14) are connected by a welded bellows.

4. The in-situ growth observation device for electrical tree dendrites based on a cryogenic objective lens according to claim 2, characterized in that: It also comprises a mounting platform (4), on which the support (12), the first vacuum cover (14) and the high-voltage discharge sample chamber (2) are arranged; and an air-floating shock absorber (5) is arranged between the support (12) and the mounting platform (4).

5. The in-situ growth observation device for electrical tree dendrites based on a cryogenic objective lens according to claim 2, characterized in that: The high-voltage discharge sample chamber (2) comprises: A ceramic high-voltage sleeve is connected to a high-voltage electrode and a ground electrode via a KF24 interface; the ceramic high-voltage sleeve is used to isolate a vacuum; a second vacuum cover (21), wherein the cold finger (13) extends into the second vacuum cover (21); and the second vacuum cover (21) and the first vacuum cover (14) are connected via a KF40 interface to conduct vacuum between the two; An objective lens cavity (22) connected to the top of the second vacuum cover (21); A transition cavity (23) is arranged at the top of the objective lens cavity (22), and the transition cavity (23) is used to connect the low-temperature objective lens in-situ observation assembly (3).

6. The in-situ growth observation device for electrical tree dendrites based on a cryogenic objective lens according to claim 5, characterized in that: The high-voltage discharge sample chamber (2) further comprises: A visualization quartz window (24) is arranged obliquely on the side of the objective lens cavity (22).

7. The in-situ growth observation device for electrical tree dendrites based on a cryogenic objective lens according to claim 5, characterized in that: The low-temperature objective lens in-situ observation assembly (3) comprises: A three-dimensional displacement slide (31) with a built-in reduction screw; A camera (32), used for taking pictures; An objective lens barrel (33) is arranged at the bottom of the camera (32), and the top of the objective lens barrel (33) is sealed by quartz glass; and the objective lens barrel (33) is arranged on the three-dimensional displacement slide table (31); A connecting tube (34), one end of which is connected to the objective lens barrel (33); The objective lens (35) is connected to an end of the connecting tube (34) facing away from the objective lens tube (33); and the connecting tube (34) extends into the transition cavity (23).

8. The device for observing in-situ growth of electrical dendrites based on a cryogenic objective lens according to claim 7, characterized in that: The connecting pipe (34) is a flexible corrugated pipe.

9. The device for observing the in-situ growth of electrical dendrites based on a cryogenic objective lens according to claim 7, characterized in that: The low-temperature objective lens in-situ observation assembly (3) further comprises a beam splitter (36), wherein the beam splitter (36) is arranged on the objective lens barrel (33), and the beam splitter (36) is used to provide visible light intensity.

10. The in-situ growth observation device for electrical tree dendrites based on a cryogenic objective lens according to claim 2, characterized in that: The first vacuum cover (14) is made of 304 stainless steel, and the interlayer is made of high vacuum multi-layer insulation material.

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