Vacuum arc-extinguishing chamber vacuum degree monitoring system and method

Abstract

The invention relates to a system and a method for monitoring the vacuum degree of a vacuum arc-extinguishing chamber, and relates to the technical field of monitoring. The system comprises a vacuum arc-extinguishing chamber and a laser detection device. The vacuum arc-extinguishing chamber comprises an aluminum oxide ceramic shell and a sapphire light-transmitting sheet; the aluminum oxide ceramic shell comprises a through hole penetrating through the aluminum oxide ceramic shell, and the sapphire light-transmitting sheet is welded in the through hole; the laser detection device emits detection laser to the interior of the vacuum arc-extinguishing chamber through the sapphire light-transmitting sheet, receives radiation laser corresponding to the detection laser, and determines the vacuum degree of the vacuum arc-extinguishing chamber based on the radiation laser. The system can improve the detection efficiency and detection precision of the vacuum degree of the vacuum arc-extinguishing chamber.

Description

Technical Field

[0001] The present application relates to the field of monitoring technology, and in particular to a vacuum degree monitoring system and method for a vacuum interrupter. Background Art

[0002] As power systems evolve toward higher voltages and larger capacities, the vacuum level of vacuum interrupters affects the circuit breaker's interrupting performance and operational reliability. For example, a deteriorating vacuum level results in increased gas pressure, which in turn reduces the breakdown voltage and impacts the circuit breaker's insulation performance. It also increases the bellows load, affecting the kinematic characteristics of the operating mechanism. Furthermore, a deteriorating vacuum level increases metal vapor and residual gas, prolonging the arc's burning time and reducing the circuit breaker's interrupting capacity. These effects ultimately reduce the circuit breaker's operational reliability and increase the risk of failure. Therefore, monitoring the vacuum level of vacuum interrupters is crucial.

[0003] Current vacuum monitoring devices for vacuum interrupters include: installing a measuring cavity and an oxygen sensor within the static conductive rod of the vacuum interrupter; using a high-voltage capacitive sensor to obtain the instantaneous current spectrum of the interrupter during opening and closing; and placing buried electrodes within the vacuum interrupter. However, due to their complex structure, these devices can cause leaks in the vacuum monitoring of the vacuum interrupter, or can only measure the vacuum level when the circuit breaker is operating, failing to monitor the vacuum level when the vacuum interrupter is static. This affects the efficiency and accuracy of vacuum detection in the vacuum interrupter. Consequently, current vacuum detection efficiency and accuracy in vacuum interrupters are low. Summary of the Invention

[0004] Based on this, it is necessary to provide a system and method to address the technical problems of low efficiency and low accuracy in detecting the vacuum degree of the vacuum interrupter.

[0005] In a first aspect, the present application provides a vacuum degree monitoring system for a vacuum interrupter, comprising a vacuum interrupter and a laser detection device;

[0006] The vacuum interrupter comprises an alumina ceramic shell and a sapphire light-transmitting sheet; the alumina ceramic shell comprises a through hole penetrating the alumina ceramic shell, and the sapphire light-transmitting sheet is welded in the through hole;

[0007] After the laser detection device emits a detection laser into the interior of the vacuum interrupter through the sapphire light-transmitting sheet, it collects a radiation laser corresponding to the detection laser and determines the vacuum degree of the vacuum interrupter based on the radiation laser.

[0008] In one embodiment, the vacuum interrupter further comprises a metal target located inside the alumina ceramic housing; the metal target is configured to sputter plasma having radiation intensity after receiving the laser.

[0009] In one embodiment, the laser detection device includes a laser emitting module and a laser receiving module; the laser emitting module is used to emit laser light toward the metal target, and the laser receiving module is used to receive the radiated laser light from the plasma.

[0010] In one embodiment, the welding connection between the sapphire light-transmitting sheet and the alumina ceramic shell includes a metal solder ring; the metal solder ring is used to offset the stress generated by welding the alumina ceramic shell and the sapphire light-transmitting sheet through deformation.

[0011] In one embodiment, the metal solder ring is a silver-copper solder ring.

[0012] In one embodiment, the welding connection between the sapphire light-transmitting sheet and the alumina ceramic housing comprises an oxygen-free copper sheet.

[0013] In one embodiment, the sapphire light-transmitting sheet and the alumina ceramic housing are welded using a high-temperature vacuum brazing furnace, with the maximum welding temperature being 810°C.

[0014] In one embodiment, during the welding process of the sapphire light-transmitting sheet and the alumina ceramic shell, the welding surface stress range of the sapphire light-transmitting sheet is 830MPa-870MPa, and the welding surface stress range of the alumina ceramic shell is 340MPa-380MPa.

[0015] In one embodiment, after the sapphire light-transmitting sheet and the alumina ceramic shell are welded, the maximum field strength on the inner edge of the alumina ceramic shell is 3.29 kV / mm, and the maximum field strength on the outer edge is 4.11 kV / mm.

[0016] In a second aspect, the present application further provides a vacuum degree monitoring method for a vacuum interrupter, which is applied to a laser detection device in a vacuum degree monitoring system for a vacuum interrupter as described above, wherein the vacuum degree monitoring system for a vacuum interrupter includes a vacuum interrupter and a laser detection device; the vacuum interrupter includes an alumina ceramic housing and a sapphire light-transmitting sheet; the alumina ceramic housing includes a through hole extending through the alumina ceramic housing, and the sapphire light-transmitting sheet is welded within the through hole;

[0017] The method includes: emitting a detection laser into the interior of the vacuum interrupter through the sapphire light-transmitting sheet, collecting a radiation laser corresponding to the detection laser, and determining the vacuum degree of the vacuum interrupter based on the radiation laser.

[0018] The above-mentioned vacuum degree monitoring system for a vacuum interrupter comprises a vacuum interrupter and a laser detection device; the vacuum interrupter comprises an alumina ceramic shell and a sapphire light-transmitting sheet; the alumina ceramic shell comprises a through-hole penetrating the alumina ceramic shell, and the sapphire light-transmitting sheet is welded in the through-hole; the laser detection device emits a detection laser into the interior of the vacuum interrupter through the sapphire light-transmitting sheet, collects a radiation laser corresponding to the detection laser, and determines the vacuum degree of the vacuum interrupter based on the radiation laser. In the above-mentioned process, a sapphire light-transmitting sheet is welded and arranged in the through-hole of the alumina ceramic shell of the vacuum interrupter, and the laser detection device emits a detection laser into the interior of the vacuum interrupter through the sapphire light-transmitting sheet, collects a radiation laser corresponding to the detection laser, and determines the vacuum degree of the vacuum interrupter based on the radiation laser. By using radiated laser to determine the vacuum degree of the vacuum interrupter, non-invasive, high-precision, and real-time online monitoring of the vacuum degree of the vacuum interrupter can be achieved. Moreover, due to the high light transmittance and high temperature and high pressure resistance of the sapphire transparent sheet, it can be directly used as an optical monitoring interface for the vacuum interrupter, replacing the traditional electrical contact sensor, reducing the number of mechanical components, making the overall structure more compact, and suitable for space-constrained scenarios such as high-voltage switchgear. In addition, sapphire has excellent brazing compatibility with metal materials such as copper or stainless steel. It can be directly welded to the alumina ceramic shell during the vacuum interrupter manufacturing process to form a permanent sealed window, reducing the risk of gas leakage while improving the mechanical strength and long-term stability of the vacuum interrupter. Therefore, the above-mentioned vacuum interrupter vacuum degree monitoring system can directly obtain the gas ionization state or particle density changes in the vacuum interrupter in real time through the sapphire transparent sheet, without triggering the opening and closing action, thereby achieving "silent monitoring" and significantly improving the detection efficiency and detection accuracy of the vacuum interrupter vacuum degree. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 2 is a schematic structural diagram of a vacuum degree monitoring system for a vacuum interrupter in one embodiment;

[0021] Figure 2 A schematic structural diagram of a vacuum interrupter vacuum degree monitoring system in another embodiment;

[0022] Figure 3 A schematic structural diagram of a metal solder ring disposed in a vacuum degree monitoring system for a vacuum interrupter according to an embodiment;

[0023] Figure 4The figure is a structural diagram of the arrangement of oxygen-free copper sheets in a vacuum degree monitoring system for a vacuum interrupter in one embodiment. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0026] It will be understood that the terms "first," "second," etc. used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element.

[0027] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intervening element. In addition, the "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc., if there is transmission of electrical signals or data between the connected objects.

[0028] When used herein, the singular forms "a", "an", and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

[0029] As power systems evolve toward higher voltages and larger capacities, vacuum interrupters, as critical equipment, face a significant impact on the circuit breaker's interrupting performance and operational reliability. Deteriorating vacuum levels can impact interrupter performance in three key ways: 1. In terms of insulation performance, increased pressure leads to a decrease in breakdown voltage, particularly at short gaps. 2. In terms of interrupting performance, increased metal vapor and residual gas prolong the arc's burning time and reduce interrupting capacity. 3. In terms of mechanical performance, increased pressure increases the bellows load, affecting the kinematic characteristics of the operating mechanism. These effects ultimately reduce the circuit breaker's operational reliability and increase the risk of failure.

[0030] However, currently commonly used methods for online monitoring of the vacuum degree of vacuum interrupter include: setting a measuring cavity and an oxygen sensor in the static conductive rod of the vacuum interrupter, the measuring cavity is connected to the internal cavity of the insulating ceramic shell through a connecting hole, and an oxygen sensor and a heating device are installed in the measuring cavity, the measuring device is started, and the monitoring data of the oxygen sensor is received, so that the online monitoring of the vacuum degree of the vacuum interrupter can be realized; and also include: using a high-speed A / D (Analog-to-Digital Converter) combined with an FPGA (Field-Programmable Gate Array) to monitor the vacuum degree of the vacuum interrupter. Array, field programmable gate array), simultaneously collects the current information of the vacuum interrupter containing high-frequency components at the moment of interrupter disconnection, and then uses the high-voltage capacitor sensor installed between the corresponding phase busbar of the circuit breaker and the ground to obtain the current spectrum of the instantaneous opening and closing of the interrupter; according to the difference in the voltage spectrum information of the voltage-dividing capacitor corresponding to the larger current generated in the vacuum interrupter at the moment of circuit breaker disconnection under different vacuum degrees, the vacuum degree of the vacuum interrupter of the circuit breaker is indirectly judged; it also includes: an embedded electrode and an external detection device welded on the end cover of the vacuum interrupter, the external detection device and the embedded electrode structure are designed to be separated, the external detection device includes a detection calculation component, a wireless transmitter, a rechargeable energy storage battery, a wireless charging coil, etc. The internal structure such as the embedded electrode can be processed into a whole with the vacuum interrupter, and detection is achieved by installing the external detection device above the embedded electrode structure.

[0031] Therefore, the structure of setting a cavity in the static conductive rod and using an oxygen sensor is relatively complicated. There is a problem of matching clearance between the sensor wiring and the parts entry and exit holes. If the parts processing tolerance is large, the tight fit cannot be guaranteed, which easily leads to product leakage and the effective vacuum degree of the product cannot be guaranteed. In addition, the operating temperature of the oxygen sensor is between 700℃ and 1000℃, and an additional heating device is required, and the internal vacuum degree of the product cannot be measured immediately; the use of a high-speed A / D acquisition module combined with FPGA and other processing modules to collect high-frequency current signals can only analyze and process the high-frequency current signals at the moment of opening and closing of the arc extinguishing chamber, that is, the vacuum degree can only be measured when the circuit breaker is operating, and the vacuum degree of the arc extinguishing chamber cannot be monitored under static conditions; the measuring device of the buried electrode in the arc extinguishing chamber requires brazing ceramic insulation parts, transmitting electrodes, receiving electrodes and electrode grids on the arc extinguishing chamber end cover. The structure is relatively complex and introduces multiple brazing points, which increases the risk of leakage. In addition, the device requires multiple brazing of components, which is time-consuming and not conducive to the mass production of arc extinguishing chambers.

[0032] In order to solve the above technical problems, the present application provides a vacuum interrupter vacuum degree monitoring system 100, such as Figures 1 to 4 As shown, it includes a vacuum interrupter 101 and a laser detection device 102;

[0033] The vacuum interrupter 101 includes an alumina ceramic shell 1011 and a sapphire light-transmitting sheet 1012; the alumina ceramic shell 1011 includes a through hole 105 that penetrates the alumina ceramic shell, and the sapphire light-transmitting sheet 1012 is welded in the through hole 105; the laser detection device 102 emits a detection laser into the vacuum interrupter 101 through the sapphire light-transmitting sheet 1012, collects the radiation laser corresponding to the detection laser, and determines the vacuum degree of the vacuum interrupter based on the radiation laser.

[0034] Among them, the vacuum interrupter 101 is used to extinguish arcs and isolate high-voltage arcs to ensure the safety and stable operation of the equipment. The internal environment of the vacuum interrupter 101 needs to maintain a certain vacuum degree to reduce the energy of the arc, thereby extending the life of the equipment; the alumina ceramic shell 1011 has high insulation, high temperature resistance, corrosion resistance, and good mechanical strength. As the shell of the vacuum interrupter 101, it can provide thermal insulation, electrical insulation and mechanical protection; the sapphire transparent sheet 1012 is made of sapphire and serves as an optical window to allow laser signals to penetrate and isolate the indoor and outdoor environments. It is used to realize non-invasive laser detection to avoid The sealing of the vacuum interrupter 101 is destroyed; the through hole 105 penetrating the alumina ceramic shell 1011 may be a through hole 105 opened on the alumina ceramic shell 1011, for installing internal components or connecting optical devices; the sapphire light-transmitting sheet 1012 welded in the through hole 105 can ensure the sealing of the vacuum interrupter 101; the laser detection device 102 can use laser emission and receiving technology to detect the state inside the vacuum interrupter 101; the vacuum degree judgment based on the radiated laser can be based on detecting changes in the intensity, scattering, polarization, etc. of the radiated laser, indirectly reflecting the vacuum state inside the vacuum interrupter 101.

[0035] Furthermore, the through hole 105 includes two parts with different projected areas at the same position and the same angle of the alumina ceramic shell 1011. The sapphire transparent sheet 1012 is sealed at the through hole 105, which can completely seal the through hole 105 to ensure that the vacuum interrupter 101 will not leak through the through hole 105.

[0036] The vacuum degree monitoring system 100 of the vacuum interrupter comprises a vacuum interrupter 101 and a laser detection device 102; the vacuum interrupter 101 comprises an alumina ceramic shell 1011 and a sapphire light-transmitting sheet 1012; the alumina ceramic shell 1011 comprises a through hole 105 penetrating the alumina ceramic shell 1011, and the sapphire light-transmitting sheet 1012 is welded in the through hole 105; the laser detection device 102 emits a detection laser into the vacuum interrupter 101 through the sapphire light-transmitting sheet 1012, collects the radiation laser corresponding to the detection laser, and determines the vacuum degree of the vacuum interrupter 101 based on the radiation laser. In the above process, the sapphire light-transmitting sheet 1012 is welded to the through hole 105 of the alumina ceramic shell 1011 of the vacuum interrupter 101, and the laser detection device 102 emits a detection laser into the vacuum interrupter 101 through the sapphire light-transmitting sheet 1012. After emitting a detection laser internally, the radiated laser corresponding to the detection laser is received, and the vacuum degree of the vacuum interrupter 101 is determined based on the radiated laser. This enables non-invasive, high-precision, real-time online monitoring of the vacuum degree of the vacuum interrupter 101. Furthermore, since the sapphire light-transmitting sheet 1012 has the characteristics of high light transmittance and resistance to high temperature and high pressure, it can be directly used as an optical monitoring interface of the vacuum interrupter 101, replacing traditional electrical contact sensors, reducing the number of mechanical components, and making the overall structure more compact, which is suitable for space-constrained scenarios such as high-voltage switchgear. In addition, sapphire has excellent brazing compatibility with metal materials such as copper or stainless steel, and can be directly welded to the alumina ceramic housing 1011 during the manufacturing process of the vacuum interrupter 101 to form a permanent sealed window, thereby reducing the risk of gas leakage while improving the mechanical strength and long-term stability of the vacuum interrupter 101. Therefore, the above-mentioned vacuum degree monitoring system of the vacuum interrupter 101 can directly obtain the gas ionization state or particle density change in the vacuum interrupter 101 in real time through the sapphire transparent plate 1012 without triggering the opening and closing action, thereby realizing "silent monitoring" and significantly improving the detection efficiency and detection accuracy of the vacuum degree of the vacuum interrupter 101.

[0037] In one embodiment, Figures 1 to 4 As shown, the vacuum interrupter 101 further includes a metal target 1013 located inside the alumina ceramic housing 1011 ; the metal target 1013 is used to sputter plasma with radiation intensity after receiving the laser.

[0038] Among them, the metal target 1013 can be a variety of metal materials, and the specific selection depends on the application requirements, laser parameters and plasma properties. Common metal target 1013 materials include copper with good thermal conductivity and electrical conductivity, tungsten with high melting point and high temperature resistance, nickel with stable chemical properties, corrosion-resistant platinum, lightweight aluminum with good electrical and thermal conductivity, and titanium with high strength and corrosion resistance.

[0039] Furthermore, in one embodiment, the laser detection device 102 includes a laser emitting module and a laser receiving module; the laser emitting module is used to emit laser light toward the metal target 1013 , and the laser receiving module is used to receive laser light radiated by the plasma.

[0040] Among them, plasma is an ionized gas state composed of a large number of ions, electrons and neutral particles, which has the characteristics of strong conductivity, luminescence, strong electromagnetic response and high energy state.

[0041] Furthermore, the laser detection device 102 can be used to emit and receive laser signals, monitor and analyze the internal plasma state, and obtain plasma radiation information through the interaction between the laser and the metal target 1013; the laser emission module is a module responsible for generating a laser beam and emitting it in a directed manner, which can be used to emit a laser toward the metal target 1013 to excite the metal target 1013 to generate plasma; the laser receiving module can be a module equipped with a photodetector or sensor, which is used to receive reflected, scattered or radiated laser signals, and to capture the laser radiation rebounded or scattered back from the plasma, and then analyze the intensity, waveform, and spectrum changes of the laser signal to determine the characteristics and state of the plasma; the plasma radiation laser is the electron radiation generated by the plasma in the excited state, and its intensity and characteristics reflect the vacuum state inside the vacuum interrupter 101. By detecting the radiation laser, the vacuum degree and arc state inside the vacuum interrupter 101 can be indirectly inferred.

[0042] By using the intensity of laser-induced plasma radiation to characterize the vacuum degree in the vacuum interrupter 101, and sealing a sapphire light-transmitting sheet 1012 on the outside of the alumina ceramic shell 1011 of the vacuum interrupter 101 to allow the injection of focused laser light, online monitoring of the vacuum degree of the vacuum interrupter 101 can be achieved. Vacuum-related parameters can be obtained in real time without disassembling the system structure, which is suitable for long-term online monitoring in high-voltage environments.

[0043] In one embodiment, Figures 1 to 4 As shown, the welding connection between the sapphire light-transmitting sheet 1012 and the alumina ceramic housing 1011 includes a metal solder ring 103; the metal solder ring 103 is used to offset the stress generated by welding the alumina ceramic housing 1011 and the sapphire light-transmitting sheet 1012 through deformation.

[0044] Among them, offsetting the stress generated by welding the alumina ceramic shell 1011 and the sapphire transparent sheet 1012 through deformation refers to utilizing the deformation ability of the metal solder ring 103 to absorb and disperse the thermal stress or mechanical stress generated during the welding process. The metal solder ring 103 is a silver-copper solder ring. Silver-copper solder is a commonly used welding material with good welding performance and electrical conductivity.

[0045] For example, in one embodiment, Figures 1 to 4 As shown, the welding connection between the sapphire light-transmitting sheet 1012 and the alumina ceramic housing 1011 includes an oxygen-free copper sheet 104 .

[0046] Among them, the oxygen-free copper sheet 104 is a high-purity copper material with excellent thermal conductivity and electrical conductivity. It can provide good thermal conductivity and mechanical support during welding; it can be used as an intermediate layer or filling material in welding to improve welding quality; it can also avoid oxidation problems and ensure that the connected metal is pure and stable. Therefore, using the oxygen-free copper sheet 104 as a connecting material can improve the heat conduction efficiency of the welding area and reduce welding stress and crack risks. In addition, the oxygen-free copper sheet 104 plays a buffering and heat-conducting role during the welding process, which helps to achieve a firm and sealed connection.

[0047] The welding connection between the above-mentioned sapphire light-transmitting sheet 1012 and the alumina ceramic shell 1011 includes an oxygen-free copper sheet 104. Through a new sealing process, the high ductility and solder wettability of the oxygen-free copper sheet 104 are utilized to convert the stress generated on the sealing surface of the alumina ceramic shell 1011 and the sapphire light-transmitting sheet 1012 into deformation of the metal parts, thereby solving the problem of matching the material thermal expansion coefficients of the sapphire light-transmitting sheet 1012 and the alumina ceramic shell 1011, and ensuring the long-term airtightness of the vacuum interrupter 101.

[0048] More as an example, Figures 1 to 4 As shown, the welded connection between the sapphire light-transmitting sheet 1012 and the alumina ceramic housing 1011 includes both a metal solder ring 103 and an oxygen-free copper sheet 104. While offsetting the stress generated by the welding of the alumina ceramic housing 1011 and the sapphire light-transmitting sheet 1012 through deformation, the oxygen-free copper sheet 104 also utilizes its high ductility and solder wettability to convert the stress generated at the sealing surface of the alumina ceramic housing 1011 and the sapphire light-transmitting sheet 1012 into deformation of the metal parts. This solves the problem of matching the thermal expansion coefficients of the sapphire light-transmitting sheet 1012 and the alumina ceramic housing 1011, ensuring the long-term airtightness of the vacuum interrupter 101. The specific arrangement and location of the metal solder ring 103 and the oxygen-free copper sheet 104 at the welded connection between the sapphire light-transmitting sheet 1012 and the alumina ceramic housing 1011 are not limited.

[0049] In one embodiment, the sapphire light-transmitting sheet 1012 and the alumina ceramic housing 1011 are welded using a high-temperature vacuum brazing furnace, with the maximum welding temperature being 810°C.

[0050] Among them, high-temperature vacuum brazing is a connection process carried out in a vacuum environment. It uses the brazing material to melt at high temperature and then realizes the metal connection between materials in an oxygen-free environment. It has the advantages of high strength, heat resistance and corrosion resistance of the welded joint, and is particularly suitable for the bonding of ceramics and metals. The high-temperature vacuum brazing furnace is a special equipment used to provide a high-temperature and oxygen-free environment to avoid oxidation and impurity contamination. By controlling the temperature and pressure, it ensures that the brazing material is fully melted and fused with the materials to be connected.

[0051] The welding of the above-mentioned sapphire light-transmitting sheet 1012 and the alumina ceramic shell 1011 is achieved by using a high-temperature vacuum brazing furnace, and the maximum welding temperature is 810°C. In the process of sealing the alumina ceramic shell 1011 and the sapphire light-transmitting sheet 1012, the sealing surfaces of the two need to be metallized first to achieve high-temperature brazing; after the metallization, oxygen-free copper sheet 104 needs to be used for sealing transition between the metallized alumina ceramic shell 1011 and the sapphire light-transmitting sheet 1012 to ensure the wettability of the solder. The sealing process is completed using a high-temperature vacuum brazing furnace, and the maximum sealing temperature is 810°C.

[0052] In one embodiment, during the welding process of the sapphire light-transmitting sheet 1012 and the alumina ceramic housing 1011 , the welding surface stress of the sapphire light-transmitting sheet 1012 ranges from 830 MPa to 870 MPa (Megapascal), and the welding surface stress of the alumina ceramic housing 1011 ranges from 340 MPa to 380 MPa.

[0053] Among them, in order to verify whether the sealing process will affect the materials of the alumina ceramic shell 1011 and the sapphire transparent sheet 1012, such as cracking at high temperature and damage to parts caused by sealing stress, it is necessary to perform stress simulation analysis of the sealing process. The calculation results show that the stress on the sealing surface of the alumina ceramic shell 1011 is about 360MPa, and the stress on the sealing surface of the sapphire transparent sheet 1012 is about 850MPa, both of which are less than the tensile strength of their respective materials. Therefore, the sealing process will not cause surface damage to the parts.

[0054] In one embodiment, after the sapphire light-transmitting sheet 1012 and the alumina ceramic housing 1011 are welded, the maximum field strength on the inner edge of the alumina ceramic housing 1011 is 3.29 kV / mm (kilovolts per millimeter), and the maximum field strength on the outer edge is 4.11 kV / mm.

[0055] Among them, in order to verify whether the sapphire transparent sheet 1012 will affect the internal and external insulation of the product during the aging process of the entire vacuum interrupter 101, such as surface breakdown of the alumina ceramic shell 1011, an electric field analysis was performed on the entire tube after sealing. The calculation results show that the maximum field strength along the inner surface of the alumina ceramic shell 1011 of the sapphire transparent sheet 1012 is 3.29 kV / mm, and the maximum field strength along the outer surface of the alumina ceramic shell 1011 of the sapphire transparent sheet 1012 is 4.11 kV / mm, both of which are lower than the critical surface field strength criterion of the alumina ceramic shell 1011 in vacuum and in air. Therefore, the sapphire transparent sheet 1012 will not have an adverse effect on the static insulation of the vacuum interrupter 101.

[0056] Furthermore, in one embodiment, a method for monitoring the vacuum degree of a vacuum interrupter is also included, which is applied to the laser detection device 102 in the vacuum degree monitoring system of the vacuum interrupter of any of the above embodiments. The vacuum interrupter vacuum degree monitoring system includes a vacuum interrupter and a laser detection device; the vacuum interrupter includes an alumina ceramic shell and a sapphire transparent sheet; the alumina ceramic shell includes a through hole passing through the alumina ceramic shell, and the sapphire transparent sheet is welded in the through hole; the method includes: after emitting a detection laser into the interior of the vacuum interrupter through the sapphire transparent sheet, collecting the radiation laser corresponding to the detection laser, and determining the vacuum degree of the vacuum interrupter based on the radiation laser.

[0057] Furthermore, after the sealing was completed, the vacuum interrupter vacuum monitoring system was tested for leaks using a helium mass spectrometer leak detector, and the leak rate was 3.6×10 -11 Pa·m3 / s (Pascal·cubic meter per second), this leakage rate can meet the requirements of whole tube assembly for vacuum interrupter.

[0058] Through the above embodiment, in order to realize online monitoring of the vacuum degree of the vacuum interrupter, a sapphire light-transmitting sheet (sapphire window) is sealed on the side of the alumina ceramic shell. Sapphire (Al2O3, aluminum oxide) has excellent physical and chemical properties, including high light transmittance, high insulation, high temperature and high pressure resistance, high hardness, high chemical stability, high thermal conductivity and good optical properties. It can be used to adapt to the extreme working conditions of the vacuum interrupter, such as high vacuum inside and high pressure outside, strong electric field inside and outside the vacuum interrupter, and high temperature generated during the interruption process of the vacuum interrupter. It is an ideal choice for window materials. Its hardness reaches 9 on the Mohs hardness scale, second only to diamond, allowing it to maintain its shape and function even in harsh environments. Compared with other window materials, sapphire's chemical inertness makes it more reliable in many applications. Furthermore, when performing online vacuum monitoring, only the laser detection device is required to allow the focused laser to pass through the sapphire light-transmitting sheet to bombard the target material (metal target, suspended shielding tube in the arc extinguishing chamber), splashing plasma. The laser detection device then measures its radiation intensity to achieve online monitoring of the vacuum degree of the vacuum interrupter.

[0059] In addition, the sapphire light-transmitting sheet is directly integrated into the alumina ceramic shell of the vacuum interrupter. As the only transmission channel for optical signals, when performing vacuum degree detection, it is only necessary to install the laser transmitting module and the laser receiving module on the outside of the sapphire light-transmitting sheet. There is no need to invade the interior of the vacuum interrupter and no need to shut down the machine, which significantly reduces the complexity of operation and maintenance. It is especially suitable for high-voltage switchgear or compact circuit breakers with limited space. In addition, the thermal expansion coefficient of sapphire material itself is close to that of oxygen-free copper. Under the high temperature of brazing, the interface stress is extremely small, which can avoid weld cracking or leakage. In addition, sapphire The sapphire light-transmitting sheet is directly brazed to the shell during the manufacturing stage of the vacuum interrupter, forming a fully sealed structure, which does not require secondary sealing when sensors are installed later. In addition, the sapphire light-transmitting sheet has a simple structure, and its brazing process can be integrated into the interrupter production line, reducing more than 30% of the assembly steps. In addition, the vacuum degree detection of the sapphire light-transmitting sheet is carried out without the need for opening and closing the circuit breaker. The vacuum interrupter is always in a closed state to avoid accidental arc reignition or transient overvoltage caused by the detection operation. Therefore, the above process significantly improves the efficiency and accuracy of vacuum degree monitoring of the vacuum interrupter.

[0060] Throughout this specification, references to terms such as "some embodiments," "other embodiments," and "desired embodiments" indicate that a particular feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Although these terms are used interchangeably throughout this specification, they do not necessarily refer to the same embodiment or example.

[0061] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0062] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A vacuum degree monitoring system for a vacuum interrupter, characterized in that: Including vacuum interrupter and laser detection device; The vacuum interrupter comprises an alumina ceramic shell and a sapphire light-transmitting sheet; the alumina ceramic shell comprises a through hole penetrating the alumina ceramic shell, and the sapphire light-transmitting sheet is welded in the through hole; After the laser detection device emits a detection laser into the interior of the vacuum interrupter through the sapphire light-transmitting sheet, it collects a radiation laser corresponding to the detection laser and determines the vacuum degree of the vacuum interrupter based on the radiation laser.

2. The vacuum interrupter vacuum degree monitoring system according to claim 1, characterized in that: The vacuum interrupter further comprises a metal target located inside the alumina ceramic housing; The metal target is used to sputter plasma with radiation intensity after receiving the laser.

3. The vacuum degree monitoring system for vacuum interrupter according to claim 2, characterized in that: The laser detection device includes a laser emitting module and a laser receiving module; The laser emitting module is used to emit laser light toward the metal target, and the laser receiving module is used to receive the laser light radiated by the plasma.

4. The vacuum interrupter vacuum degree monitoring system according to claim 1, characterized in that: The welding connection between the sapphire light-transmitting sheet and the alumina ceramic housing includes a metal solder ring; The metal solder ring is used to offset the stress generated by welding the alumina ceramic housing and the sapphire light-transmitting sheet through deformation.

5. The vacuum interrupter vacuum degree monitoring system according to claim 4, characterized in that: The metal solder ring is a silver-copper solder ring.

6. The vacuum interrupter vacuum degree monitoring system according to claim 1, characterized in that: The welding connection between the sapphire light-transmitting sheet and the alumina ceramic housing comprises an oxygen-free copper sheet.

7. The vacuum interrupter vacuum degree monitoring system according to claim 1, characterized in that: The sapphire light-transmitting sheet and the alumina ceramic housing are welded in a high-temperature vacuum brazing furnace, with the maximum welding temperature being 810°C.

8. The vacuum interrupter vacuum degree monitoring system according to claim 1, characterized in that: During the welding process of the sapphire light-transmitting sheet and the alumina ceramic shell, the stress range of the welding surface of the sapphire light-transmitting sheet is 830 MPa-870 MPa, and the stress range of the welding surface of the alumina ceramic shell is 340 MPa-380 MPa.

9. The vacuum interrupter vacuum degree monitoring system according to claim 1, characterized in that: After the sapphire light-transmitting sheet and the alumina ceramic shell are welded, the maximum field strength on the inner edge surface of the alumina ceramic shell is 3.29 kV / mm, and the maximum field strength on the outer edge surface is 4.11 kV / mm.

10. A method for monitoring the vacuum degree of a vacuum interrupter, characterized in that: A laser detection device used in a vacuum degree monitoring system for a vacuum interrupter according to any one of claims 1 to 9, wherein the vacuum interrupter vacuum degree monitoring system comprises a vacuum interrupter and a laser detection device; the vacuum interrupter comprises an alumina ceramic housing and a sapphire light-transmitting sheet; the alumina ceramic housing comprises a through hole extending therethrough, and the sapphire light-transmitting sheet is welded within the through hole; The method comprises: After emitting a detection laser into the interior of the vacuum interrupter through the sapphire light-transmitting sheet, a radiation laser corresponding to the detection laser is collected, and the vacuum degree of the vacuum interrupter is determined based on the radiation laser.

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