Environment-friendly tank-type double-break vacuum circuit breaker

Abstract

The utility model relates to the field of vacuum circuit breaker, concretely relates to an environmental protection type tank type double-break vacuum circuit breaker, include: casing, two vacuum interrupters that symmetrically set in the casing, transmission case that sets between two vacuum interrupters, the inside of casing forms the high gas pressure chamber sealed with external environment, and the high gas pressure chamber is filled with first environmental protection insulating gas, the inside of transmission case forms the low gas pressure chamber sealed with high gas pressure chamber, and the low gas pressure chamber is filled with second environmental protection insulating gas, and the outside space of the bellows of two vacuum interrupters all with the inside space of low gas pressure chamber is linked together, the utility model discloses the transmission case is designed as independent low gas pressure chamber, and makes the bellows of vacuum interrupter and it link together, make the bellows bear only lower gas pressure, and not directly expose in the high pressure insulating gas in the tank body, therefore greatly reduced the mechanical stress of bellows, avoided its risk of failure because of high pressure fatigue.

Description

Technical Field

[0001] This utility model relates to the field of vacuum circuit breakers, specifically to an environmentally friendly tank-type double-break vacuum circuit breaker, and more particularly to a 252kV environmentally friendly tank-type double-break vacuum circuit breaker. Background Technology

[0002] In high-voltage and ultra-high-voltage power transmission and distribution systems, high-voltage circuit breakers are key core equipment for power grid protection and control. Vacuum and SF6 are currently the most widely used arc-extinguishing and insulating media in circuit breakers. SF6 circuit breakers have been widely used in high-voltage fields (110kV and above) due to their excellent insulation performance and arc-extinguishing capability. However, SF6 is the strongest known greenhouse gas and easily generates harmful derivatives in high-voltage equipment, seriously threatening environmental and personnel safety. Currently, countries worldwide are increasing restrictions on the use of SF6. Therefore, researching and gradually replacing SF6 circuit breakers with high-voltage vacuum circuit breakers using environmentally friendly gas insulation is a future development trend. Utility Model Content

[0003] The technical problem to be solved by this utility model is the insufficient safety and environmental protection of the insulating medium and the low stability of the circuit breaker. The purpose is to provide an environmentally friendly tank-type double-break vacuum circuit breaker. By using environmentally friendly gases such as nitrogen and carbon dioxide as the insulating medium in the entire device, the use of SF6 is replaced, making the circuit breaker product greener and more environmentally friendly, which meets the requirements of sustainable development in the power industry.

[0004] This utility model is achieved through the following technical solution:

[0005] An environmentally friendly tank-type double-break vacuum circuit breaker includes: a housing, two vacuum interrupting chambers symmetrically arranged within the housing, an operating mechanism for driving the opening and closing of the vacuum interrupting chambers, and a transmission box disposed between the two vacuum interrupting chambers.

[0006] The operating mechanism is connected to the transmission component located in the transmission box via an insulating pull rod, and synchronously drives the moving contacts of the two vacuum interrupters;

[0007] The interior of the shell forms a high-pressure chamber that is sealed from the external environment, and the high-pressure chamber is filled with a first environmentally friendly insulating gas.

[0008] The transmission box has a low-pressure chamber that is sealed to the high-pressure chamber. The low-pressure chamber is filled with a second environmentally friendly insulating gas, and the external space of the bellows of the two vacuum interrupters is connected to the internal space of the low-pressure chamber.

[0009] Optionally, the circuit breaker is provided with basin-type insulators symmetrically at both ends of the housing;

[0010] The stationary end of the vacuum interrupter is connected to the corresponding basin insulator via a stationary end fixing seat. The stationary conductive rod of the vacuum interrupter is connected to the stationary end fixing seat. The moving end of the vacuum interrupter is connected to the transmission box via a moving end fixing seat. The moving conductive rod of the vacuum interrupter is connected to the transmission assembly of the transmission box.

[0011] A stationary end shielding cover is provided on the outside of the stationary end fixing seat, and a moving end shielding cover is provided on the outside of the moving end fixing seat.

[0012] Optionally, the circuit breaker further includes equalizing capacitors connected in parallel across the two vacuum interrupters;

[0013] The voltage equalizing capacitor includes a first capacitor and a second capacitor connected in series. An intermediate shield is provided at the connection between the first capacitor and the second capacitor. The intermediate shield is electrically connected to the main shield of the vacuum interrupter.

[0014] One side of the voltage equalizing capacitor is fixedly connected to the stationary end fixing base, and the other side of the voltage equalizing capacitor is fixedly connected to the moving end shielding cover.

[0015] Furthermore, the circuit breaker also includes: an insulating support base and an insulating rod shield. The insulating support base is fixedly disposed inside the housing and located between the housing and the transmission box. One end of the insulating rod passes through the insulating support base and is connected to the transmission assembly of the transmission box. The other end of the insulating rod is connected to the operating mechanism outside the housing. The insulating rod shield is connected to the transmission box and surrounds the outside of the insulating rod.

[0016] Optionally, the transmission assembly of the transmission box includes an M-type transmission device. The inner end of the insulating pull rod is connected to the M-type transmission device. The M-type transmission device is connected to the moving conductive rods of the two vacuum interrupters respectively through two overtravel springs, thereby converting the single input motion of the insulating pull rod into the synchronous opposite or opposite motion of the two moving conductive rods.

[0017] Optionally, the M-type transmission device includes: a symmetrically arranged large transmission link and a small transmission link, the end of the insulating pull rod is connected to one end of the small transmission link, and the other end of the small transmission link is connected to the middle of the large transmission link;

[0018] One end of the transmission connecting rod is pivotally connected to the bottom of the transmission box, and the other end of the transmission connecting rod is connected to the corresponding overtravel spring via a steering coupling.

[0019] Optionally, a conductive copper busbar is provided inside the transmission box, and both moving end fixing seats extend into the transmission box and are electrically connected to both ends of the conductive copper busbar, connecting the two vacuum interrupters in series; the moving conductive rods of the vacuum interrupters are all connected to the corresponding moving end fixing seats through a set of watch strap contact fingers.

[0020] Optionally, the pressure of the first environmentally friendly insulating gas is 0.4 MPa to 0.9 MPa; and the pressure of the second environmentally friendly insulating gas is 0.15 MPa to 0.2 MPa.

[0021] Optionally, the housing is provided with multiple detachable access ports, which are sealed to the corresponding cover plates by sealing rings;

[0022] The inspection port includes an inspection end cover and an inflatable inspection cover located on the upper part of the housing, and a bottom sealing cover located on the lower part of the housing;

[0023] The inflatable maintenance cover is provided with an inflation port for filling the high-pressure chamber with a first environmentally friendly insulating gas.

[0024] The transmission box is provided with a low-pressure chamber filling port for filling or releasing the second environmentally friendly insulating gas into the low-pressure chamber.

[0025] Optionally, at least one set of buffer disc springs is provided at the connection between the equalizing capacitor and the stationary end fixing seat.

[0026] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0027] The circuit breaker of this utility model has two vacuum interrupting chambers symmetrically arranged in a common sealed housing, and a transmission box is arranged between the two interrupting chambers. A high-pressure insulating chamber filled with high-pressure environmentally friendly gas is formed in the housing, while a low-pressure protective chamber filled with low-pressure environmentally friendly gas is formed in the transmission box.

[0028] By using environmentally friendly gases such as nitrogen and carbon dioxide as insulating media throughout the equipment, the use of sulfur hexafluoride (SF6), a strong greenhouse gas, is completely replaced, making the circuit breaker products greener and more environmentally friendly, and in line with the requirements of sustainable development in the power industry.

[0029] By designing the transmission box as an independent low-pressure chamber and connecting it to the bellows of the vacuum interrupter, the bellows is subjected to only a lower gas pressure, rather than being directly exposed to the high-pressure insulating gas inside the tank. This greatly reduces the mechanical stress on the bellows and avoids the risk of failure due to high-pressure fatigue. Attached Figure Description

[0030] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention, and are included in and constitute a part of this specification, but do not constitute a limitation on the embodiments of the present invention.

[0031] Figure 1 This is a structural schematic diagram of an environmentally friendly tank-type double-break vacuum circuit breaker according to the present invention.

[0032] Figure 2 This is a front view of the structure of an environmentally friendly tank-type double-break vacuum circuit breaker according to the present invention, showing the open state.

[0033] Figure 3 This is a top view of the structure of an environmentally friendly tank-type double-break vacuum circuit breaker according to the present invention, showing the open state.

[0034] Figure 4 This is a structural side view of an environmentally friendly tank-type double-break vacuum circuit breaker according to the present invention, showing the open state.

[0035] Figure 5 This is a front view of the structure of an environmentally friendly tank-type double-break vacuum circuit breaker according to the present invention, showing the closed state.

[0036] Figure 6 This is a top view of the structure of an environmentally friendly tank-type double-break vacuum circuit breaker according to the present invention, showing the closed state.

[0037] Figure 7 This is a structural side view of an environmentally friendly tank-type double-break vacuum circuit breaker according to the present invention, showing the closed state.

[0038] Reference numerals: 1-Pot-type insulator, 2-1-End shield, 2-2-Stationary end shield, 2-3-Intermediate shield, 2-4-Moving end shield, 2-5-Insulating tie rod shield, 3-Stationary end fixing seat, 4-Vacuum interrupter, 5-1-First capacitor, 5-2-Second capacitor, 6-Moving end fixing seat, 7-Transmission box, 8-Insulating support seat, 9-Insulating tie rod, 1-01-Inspection end cover, 1-02-Inflatable inspection cover, 11-Main shield. 12-Fixed flange, 13-Bottom sealing cover, 14-1-First environmentally friendly insulating gas, 14-2-Second environmentally friendly insulating gas, 15-Buffer disc spring, 16-Low pressure chamber filling port, 17-Operating mechanism, 18-Housing, 19-1-Static conductive rod, 19-2-Moving conductive rod, 20-Conductive copper busbar, 21-1-Overtravel spring, 22-Watchband contact finger, 23-1-Steering coupling shaft, 24-1-Major transmission connecting rod, 25-1-Minor transmission connecting rod. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this utility model.

[0040] It should also be noted that, for ease of description, only the parts relevant to this utility model are shown in the accompanying drawings.

[0041] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0042] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0043] Where there is no conflict, the embodiments and features of the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0044] Vacuum interruption technology has been successfully applied in medium-voltage applications due to its advantages such as being environmentally friendly and pollution-free, having strong breaking capacity, and long service life. To extend the advantages of vacuum circuit breakers to high-voltage and even ultra-high-voltage levels, a multi-break technology scheme that connects multiple vacuum interruptors in series is typically used to share the high voltage load of the system.

[0045] While multi-break solutions are theoretically feasible, they still face challenges in practical engineering implementation. For example, ensuring highly synchronized mechanical operation of all series-connected vacuum interrupters during opening and closing to prevent individual breaks from experiencing overvoltage and causing failure; achieving uniform voltage distribution among breaks during dynamic processes; and designing a compact, reliable mechanical operating system capable of simultaneously driving multiple breaks are all ongoing technical issues that this field is continuously focusing on and striving to resolve. Furthermore, when the vacuum interrupter is placed in an externally pressurized gas environment, the mechanical reliability and long-term operational stability of its external components (such as metal bellows) are also important factors that require careful consideration in engineering design.

[0046] Example 1

[0047] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown, this embodiment describes the basic architecture and core working principle of an environmentally friendly tank-type double-break vacuum circuit breaker. Through a dual-chamber partition design, it ensures high-voltage insulation performance while solving the reliability problem of key components in complex environments, thereby achieving a balance between environmental protection and high performance.

[0048] The vacuum interrupter 4 is the core arc-extinguishing unit of the circuit breaker. It is a sealed container that maintains a high degree of vacuum inside, containing a pair of separable moving and stationary contacts. When the circuit breaker operates, the contacts separate in the vacuum, and the generated arc is quickly extinguished due to the lack of free medium, thereby interrupting the current.

[0049] In power engineering, there are physical limits to the voltage levels that a single vacuum interrupter 4 can withstand and break. When the system voltage rises to very high voltage or extra-high voltage levels (such as 252kV in this example), a single interrupter often cannot meet the insulation and breaking requirements. Therefore, this embodiment adopts a double-break design, the core reason for which is voltage division. By electrically connecting the two vacuum interrupters 4 in series, the high voltage of the entire system can be distributed to the two series-connected breaks when the circuit breaker is in the breaking state.

[0050] This allows each independent vacuum interrupter 4 to withstand only about half of the total voltage, reducing the voltage withstand capability requirements for individual interruption units and enabling the vacuum interrupter 4 to be applied in high-voltage fields.

[0051] An environmentally friendly tank-type double-break vacuum circuit breaker includes: a housing 18, two vacuum interrupting chambers 4 symmetrically arranged in the housing 18, an operating mechanism 17 for driving the vacuum interrupting chambers 4 to open and close, and a transmission box 7 arranged between the two vacuum interrupting chambers 4.

[0052] The operating mechanism 17 is connected to the transmission component set in the transmission box 7 via the insulating pull rod 9, and synchronously drives the moving contacts of the two vacuum interrupters 4;

[0053] The interior of the housing 18 forms a high-pressure chamber sealed from the external environment, filled with a first environmentally friendly insulating gas 14-1. The entire internal space of the housing 18 constitutes a sealed high-pressure chamber filled with the first environmentally friendly insulating gas (such as nitrogen or dry air), maintaining a high pressure level. Its main function is to provide an external insulating environment for all high-voltage components inside the housing 18, including the exterior of the vacuum interrupter 4, connecting conductors, and supporting insulating components, preventing flashover discharge to ground or between phases under high voltage.

[0054] The transmission box 7 forms a low-pressure chamber that is sealed to the high-pressure chamber. The low-pressure chamber is filled with a second environmentally friendly insulating gas 14-2, and the external space of the bellows of the two vacuum interrupters 4 is connected to the internal space of the low-pressure chamber. Between the two vacuum interrupters 4, an independent transmission box 7 is set up. The transmission box 7 is not only used to house the mechanical transmission components, but it is also designed as a low-pressure chamber that is sealed to the high-pressure chamber and filled with the second environmentally friendly insulating gas 14-2, but its pressure is maintained at a level lower than that of the high-pressure chamber.

[0055] Pressure isolation of the bellows is achieved through a high-pressure chamber and a low-pressure chamber. The bellows, a key component of the vacuum interrupter 4, is an axially expandable metal diaphragm that transmits external mechanical operations to the internal moving contact while ensuring absolute sealing inside the vacuum interrupter 4. In this embodiment, the external space of the bellows in the vacuum interrupter 4 is connected to the low-pressure chamber inside the transmission box 7. That is, as a flexible mechanical component, the bellows is only subjected to the difference between the "low-pressure chamber pressure" and the "internal vacuum," thus being isolated from the high-pressure chamber and avoiding direct exposure to the enormous pressure of the high-pressure insulating gas.

[0056] Example 2

[0057] In order to safely introduce external high-voltage electrical energy into the internally grounded metal casing 18, the circuit breaker is provided with basin-type insulators 1 symmetrically at both ends of the casing 18. The function of the basin-type insulator 1 is to allow the high-voltage conductor to pass through the metal casing 18 with zero potential, while also being able to withstand a huge voltage difference without breakdown. It is both a current channel and an insulation barrier and mechanical support.

[0058] The stationary end of the vacuum interrupter 4 is connected to the corresponding basin insulator 1 through the stationary end fixing seat 3, and the stationary conductive rod 19-1 of the vacuum interrupter 4 is connected to the stationary end fixing seat 3, forming a conductive path from the external high-voltage line to the stationary contact of the interrupter.

[0059] The moving end of the vacuum interrupter 4 is connected to the transmission box 7 via the moving end fixing seat 6, and the moving conductive rod 19-2 of the vacuum interrupter 4 is connected to the transmission assembly of the transmission box 7, forming a mechanical connection path from the moving contact to the driving source.

[0060] A stationary end shield 2-2 is installed on the outside of the stationary end fixing seat 3, and a moving end shield 2-4 is installed on the outside of the moving end fixing seat 6. In high-voltage equipment, shields typically refer to smooth-shaped metal covers used to cover components where electric fields tend to concentrate (such as connection points and sharp edges). Their function is to make the electric field distribution more uniform and smooth, preventing excessively strong local electric fields from causing discharge, thereby improving the overall insulation level of the equipment.

[0061] Example 3

[0062] To ensure that the voltage between the two series-connected breaks can be evenly distributed, the circuit breaker also includes equalizing capacitors connected in parallel across the two vacuum interrupters 4. The equalizing capacitors are electrically connected in parallel with the breaks of the vacuum interrupters 4. Their main function is to provide a definite distribution path for the voltage after the circuit breaker is opened, ensuring that the multiple series-connected breaks can "equally share" the high voltage of the entire system, and preventing a break from being damaged by excessively high voltage due to stray capacitance and other factors.

[0063] One side of the equalizing capacitor is fixedly connected to the stationary end fixing base 3, and the other side of the equalizing capacitor is fixedly connected to the moving end shield 2-4. The equalizing capacitor includes a first capacitor 5-1 and a second capacitor 5-2 connected in series. An intermediate shield 2-3 is provided at the connection between the first capacitor 5-1 and the second capacitor 5-2. The intermediate shield 2-3 is electrically connected to the main shield 11 of the vacuum interrupter 4. The main shield 11 is usually a non-grounded, floating metal shield ring near the break point of the vacuum interrupter 4. The potential of the main shield 11 plays a decisive role in the electric field distribution inside the interrupter. The best electric field distribution inside the vacuum interrupter 4 can be achieved when the potential of the main shield 11 of the vacuum interrupter 4 is around 50% of the break point voltage. By utilizing the inherent voltage-dividing characteristics of series capacitors, the potential of the midpoint of the capacitor chain (i.e., the 50% voltage point) is directly applied to the main shield 11 of the vacuum interrupter 4, actively "clamping" the potential of the main shield 11 at the most ideal value, thereby greatly optimizing the electric field inside the vacuum interrupter 4 and significantly improving its withstand voltage capability.

[0064] At least one set of buffer disc springs 15 is provided at the connection between the voltage equalizing capacitor and the stationary terminal fixing base 3. Since the voltage equalizing capacitor is usually made of brittle materials such as ceramic, it is easily damaged by the severe mechanical impact generated during the high-speed opening and closing of the circuit breaker. The buffer disc springs 15 are compressed at the moment of impact, absorbing most of the impact energy, thus effectively protecting the voltage equalizing capacitor and reducing damage to the voltage equalizing capacitor caused by the impact of the closing operation.

[0065] Example 4

[0066] This embodiment first provides a mechanical support and insulation protection structure for the main operating linkage of the circuit breaker. The circuit breaker also includes: an insulating support base 8 and an insulating pull rod shield 2-5. The insulating support base 8 is fixedly installed inside the housing 18 and located between the housing 18 and the transmission box 7. The end of the insulating pull rod 9 passes through the insulating support base 8 and is connected to the transmission assembly of the transmission box 7. The other end of the insulating pull rod 9 is connected to the operating mechanism 17 outside the housing 18. The insulating pull rod shield 2-5 is connected to the transmission box 7 and surrounds the outside of the insulating pull rod 9.

[0067] The insulating support base 8 serves as a stable base or bracket, supporting the entire transmission box 7 and the two connected vacuum interrupters 4 from below, ensuring its stability even when subjected to enormous operating forces.

[0068] The insulating pull rod 9 is a long, rod-shaped insulating component, with its two ends connected to the high-potential transmission box 7 and the zero-potential operating mechanism 17, respectively. Therefore, its surface is subjected to extremely high electric field strength. The function of the insulating pull rod shield 2-5 is to optimize the electric field distribution around the pull rod, making its gradient gentle and preventing flashover discharge on the pull rod surface due to electric field concentration, thereby ensuring the insulation reliability of the operating link.

[0069] The transmission box 7 is equipped with a conductive copper busbar 20. Both moving end fixing seats 6 extend into the transmission box 7 and are electrically connected to the two ends of the conductive copper busbar 20 respectively, connecting the two vacuum interrupters 4 in series. The moving conductive rods 19-2 of the vacuum interrupter 4 are connected to the corresponding moving end fixing seats 6 through a set of watch strap contact fingers 22.

[0070] The horizontally arranged conductive copper busbar 20 electrically connects the left and right breaks. The ends of the moving end fixing seats 6 of the two vacuum interrupters 4 extend into the transmission box 7 and are firmly connected to the two ends of the conductive copper busbar 20, thereby connecting the two originally independent vacuum interrupters 4 in series.

[0071] The watchband contact 22 is a ring structure composed of many elastic conductive metal fingers. It can tightly grip the moving conductive rod 19-2, and even when the conductive rod passes through its center and moves axially, it can maintain a stable, low-resistance electrical contact due to its own elasticity. The watchband contact 22 allows current to be transferred from the moving conductive rod 19-2 to the stationary moving end fixing seat 6, thereby flowing into the conductive copper busbar 20.

[0072] This embodiment also provides a structure for how the transmission assembly can drive the two vacuum interrupters 4 to open and close synchronously.

[0073] The transmission assembly of the transmission box 7 includes an M-type transmission device. The inner end of the insulating pull rod 9 is connected to the M-type transmission device. The M-type transmission device is connected to the moving conductive rods 19-2 of the two vacuum interrupters 4 through two overtravel springs 21-1, which converts the single input motion of the insulating pull rod 9 into the synchronous opposite or opposite motion of the two moving conductive rods 19-2.

[0074] The M-type transmission device includes: a symmetrically arranged large transmission link 24-1 and a small transmission link 25-1. The end of the insulating pull rod 9 is connected to one end of the small transmission link 25-1, and the other end of the small transmission link 25-1 is connected to the middle of the large transmission link 24-1.

[0075] When the insulating pull rod 9 pushes the transmission small connecting rod 25-1 upward, the force acts on the middle of the transmission large connecting rod 24-1, which will force the transmission large connecting rod 24-1 with the bottom as the fulcrum to rotate. Its other end (i.e., at the steering shaft 23-1) will generate a horizontal outward movement, thereby pushing the overtravel spring 21-1 and the moving conductive rod 19-2 to achieve the closing of the circuit.

[0076] One end of the transmission connecting rod 24-1 is pivotally connected to the bottom of the transmission box 7, and the other end of the transmission connecting rod 24-1 is connected to the corresponding overtravel spring 21-1 via the steering coupling 23-1. The function of the overtravel spring 21-1 is as follows: when the circuit breaker is closed and the moving and stationary contacts have just made contact, the external operating mechanism 17 will push the connecting rod to continue moving a short distance (this distance is called "overtravel"). The overtravel will further compress the spring, allowing it to store a large amount of energy, thereby providing a stable and strong contact pressure (called "final contact pressure") for the closed contacts, ensuring low resistance between the contacts and preventing contact welding under high current.

[0077] Example 5

[0078] The pressure of the first environmentally friendly insulating gas 14-1 (such as N2, CO2, dry air, etc.) is 0.4MPa to 0.9MPa; this ensures that the environmentally friendly gas (whose insulating properties are usually weaker than SF6) has sufficient dielectric density, thereby providing strong and reliable insulation for all high-voltage components inside the circuit breaker, sufficient to withstand the working voltage of 252kV and the corresponding impulse voltage, and preventing internal discharge.

[0079] The pressure of the second environmentally friendly insulating gas 14-2 (such as N2, CO2, dry air, etc.) is 0.15MPa to 0.2MPa, which can form a clean and dry micro-positive pressure environment inside the transmission box 7, but is much lower than the pressure of the high-pressure chamber, thereby ensuring that the internal and external pressure difference of the bellows of the vacuum interrupter 4 is kept at a low level, thus achieving effective protection for it.

[0080] The housing 18 has multiple detachable access ports, which are sealed to the corresponding cover plates (such as the access end cover 1-01 and the bottom sealing cover 13) by sealing rings.

[0081] The access port includes an access end cover 1-01 and an inflatable access cover 1-02 located on the upper part of the housing 18, and a bottom sealing cover 13 located on the lower part of the housing 18;

[0082] The inflatable maintenance cover 1-02 is provided with an inflation port for filling the high-pressure chamber with the first environmentally friendly insulating gas 14-1, which is used to evacuate, fill or replenish the high-pressure chamber with the first environmentally friendly insulating gas 14-1.

[0083] The transmission box 7 is provided with a low-pressure chamber filling port 16 for filling or releasing the second environmentally friendly insulating gas 14-2 into the low-pressure chamber, and for evacuating, filling or replenishing the low-pressure chamber with the second environmentally friendly insulating gas 14-2.

[0084] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0085] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0086] Those skilled in the art should understand that the above embodiments are merely for clearly illustrating the present invention and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications can be made based on the above-described invention, and these changes or modifications still fall within the scope of the present invention.

Claims

1. An environmentally friendly tank-type double-break vacuum circuit breaker, characterized in that, include: The housing (18), two vacuum interrupters (4) symmetrically arranged inside the housing (18), an operating mechanism (17) for driving the opening and closing of the vacuum interrupters (4), and a transmission box (7) arranged between the two vacuum interrupters (4). The operating mechanism (17) is connected to the transmission assembly set in the transmission box (7) through the insulating pull rod (9) to synchronously drive the moving contacts of the two vacuum interrupters (4); The interior of the housing (18) forms a high-pressure chamber that is sealed to the external environment, and the high-pressure chamber is filled with a first environmentally friendly insulating gas (14-1). The transmission box (7) forms a low-pressure chamber that is sealed to the high-pressure chamber. The low-pressure chamber is filled with a second environmentally friendly insulating gas (14-2), and the external space of the bellows of the two vacuum interrupters (4) is connected to the internal space of the low-pressure chamber.

2. The environmentally friendly tank-type double-break vacuum circuit breaker according to claim 1, characterized in that, The circuit breaker has basin-type insulators (1) symmetrically arranged at both ends of the housing (18); The stationary end of the vacuum interrupter (4) is connected to the corresponding basin insulator (1) through the stationary end fixing seat (3), the stationary conductive rod (19-1) of the vacuum interrupter (4) is connected to the stationary end fixing seat (3), the moving end of the vacuum interrupter (4) is connected to the transmission box (7) through the moving end fixing seat (6), and the moving conductive rod (19-2) of the vacuum interrupter (4) is connected to the transmission assembly of the transmission box (7). A stationary end shield (2-2) is provided on the outside of the stationary end fixing seat (3), and a moving end shield (2-4) is provided on the outside of the moving end fixing seat (6).

3. The environmentally friendly tank-type double-break vacuum circuit breaker according to claim 2, characterized in that, The circuit breaker also includes equalizing capacitors connected in parallel across the two vacuum interrupters (4); The equalizing capacitor includes a first capacitor (5-1) and a second capacitor (5-2) connected in series. An intermediate shield (2-3) is provided at the connection between the first capacitor (5-1) and the second capacitor (5-2). The intermediate shield (2-3) is electrically connected to the main shield (11) of the vacuum interrupter (4). One side of the equalizing capacitor is fixedly connected to the stationary end fixing seat (3), and the other side of the equalizing capacitor is fixedly connected to the moving end shield (2-4).

4. The environmentally friendly tank-type double-break vacuum circuit breaker according to claim 1, characterized in that, The circuit breaker further includes an insulating support base (8) and an insulating rod shield (2-5). The insulating support base (8) is fixedly disposed inside the housing (18) and located between the housing (18) and the transmission box (7). The end of the insulating rod (9) passes through the insulating support base (8) and is connected to the transmission assembly of the transmission box (7). The other end of the insulating rod (9) is connected to the operating mechanism (17) outside the housing (18). The insulating rod shield (2-5) is connected to the transmission box (7) and surrounds the outside of the insulating rod (9).

5. The environmentally friendly tank-type double-break vacuum circuit breaker according to claim 2, characterized in that, The transmission assembly of the transmission box (7) includes an M-type transmission device. The inner end of the insulating pull rod (9) is connected to the M-type transmission device. The M-type transmission device is connected to the moving conductive rods (19-2) of the two vacuum interrupters (4) respectively through two overtravel springs (21-1), which converts the single input motion of the insulating pull rod (9) into the synchronous opposite or opposite motion of the two moving conductive rods (19-2).

6. The environmentally friendly tank-type double-break vacuum circuit breaker according to claim 5, characterized in that, The M-type transmission device includes: a symmetrically arranged large transmission link (24-1) and a small transmission link (25-1), the end of the insulating pull rod (9) is connected to one end of the small transmission link (25-1), and the other end of the small transmission link (25-1) is connected to the middle of the large transmission link (24-1). One end of the transmission connecting rod (24-1) is pivotally connected to the bottom of the transmission box (7), and the other end of the transmission connecting rod (24-1) is connected to the corresponding overtravel spring (21-1) through the steering coupling (23-1).

7. The environmentally friendly tank-type double-break vacuum circuit breaker according to claim 2, characterized in that, The transmission box (7) is provided with a conductive copper busbar (20). The two moving end fixing seats (6) extend into the transmission box (7) and are electrically connected to the two ends of the conductive copper busbar (20) respectively, connecting the two vacuum interrupters (4) in series. The moving conductive rods (19-2) of the vacuum interrupter (4) are connected to the corresponding moving end fixing seats (6) through a set of watch strap fingers (22).

8. The environmentally friendly tank-type double-break vacuum circuit breaker according to claim 1, characterized in that, The pressure of the first environmentally friendly insulating gas (14-1) is 0.4 MPa to 0.9 MPa; the pressure of the second environmentally friendly insulating gas (14-2) is 0.15 MPa to 0.2 MPa.

9. The environmentally friendly tank-type double-break vacuum circuit breaker according to claim 1, characterized in that, The housing (18) has multiple detachable inspection ports, which are sealed to the corresponding cover plates by sealing rings; The inspection port includes an inspection end cover (1-01) and an inflatable inspection cover (1-02) disposed on the upper part of the housing (18), and a bottom sealing cover (13) disposed on the lower part of the housing (18). The inflatable maintenance cover (1-02) is provided with an inflation port for filling the high-pressure chamber with the first environmentally friendly insulating gas (14-1); The transmission box (7) is provided with a low-pressure chamber filling port (16) for filling or releasing the second environmentally friendly insulating gas (14-2) into the low-pressure chamber.

10. An environmentally friendly tank-type double-break vacuum circuit breaker according to claim 3, characterized in that, At least one set of buffer disc springs (15) is provided at the connection between the equalizing capacitor and the stationary end fixing seat (3).

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