A three-phase common air chamber cable termination structure with isolation break

Abstract

This invention provides a three-phase common-chamber cable termination structure with an isolation break, comprising a three-phase common-enclosure shell, a three-phase internal transmission unit, a manual operation unit, a pressure relief unit, a molecular sieve, a dry-type cable termination, a basin-type insulator, a voltage detector, a density relay, a grounding terminal, and a shaft seal. The advantages of this invention include: reasonable design structure, stable performance, low manufacturing cost, low procurement and management cost, low material management cost, convenient installation during manufacturing, simple on-site installation and testing, and safe and reliable operation.

Description

Technical Field

[0001] This invention belongs to the field of high-voltage switch technology, and in particular relates to a three-phase common gas chamber cable terminal structure with isolation break. Background Technology

[0002] Based on the requirement in Q / GDW 13097.1-2018 "Procurement Standard for 126kV~550kV Gas-Insulated Metal-Enclosed Switchgear Part 1: General Technical Specifications" that cable terminals should be equipped with removable connecting conductors to isolate the cable from the GIS during insulation testing, most cable terminals currently on the market are equipped with removable conductors. However, during on-site installation and testing, multiple disassembly and reassembly of these removable conductors are required, necessitating repeated gas filling and opening of the gas canister. This increases the workload on-site and also raises the risk of product discharge. This application proposes a three-phase common-chamber cable terminal structure with an isolation break. The isolation break allows for manual operation of the mechanism to open and close the break after a single installation, achieving cable and GIS isolation, avoiding multiple disassembly and improving product safety and reliability. Summary of the Invention

[0003] In view of this, the present invention aims to propose a cable terminal structure with a three-phase common gas chamber and an isolation break to solve the problems of unstable performance, high manufacturing cost, inconvenient installation during manufacturing, complex on-site installation and testing, and unsafe and unreliable operation of existing cable terminals.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] A three-phase common-chamber cable termination structure with an isolation break includes:

[0006] The three-phase common enclosure has three process holes on its surface. The three process holes are used to install basin-type insulators. The three-phase common enclosure is used as an installation carrier.

[0007] A three-phase internal drive unit is installed inside the three-phase common housing and is used to realize the opening and closing operation of the disconnecting switch.

[0008] A manual operating unit is installed on one side of the three-phase common housing, and the output shaft of the manual operating unit passes through the three-phase common housing and is connected to one end of the three-phase internal transmission unit;

[0009] A pressure relief unit is installed on the outside of the other side of the three-phase common tank housing, and the pressure relief unit is connected to the inside of the three-phase common tank housing;

[0010] A molecular sieve is installed inside the other side of the three-phase common tank shell, and the molecular sieve corresponds to the pressure relief unit;

[0011] Three dry-type cable terminals are respectively installed at the bottom of the interior of the three-phase common enclosure, and all three dry-type cable terminals are connected to the three-phase internal transmission unit.

[0012] Three basin-type insulators are respectively installed on the outside of one side of the three-phase common enclosure, and the three basin-type insulators are connected to the inside of the three-phase common enclosure. All three basin-type insulators are connected to the three-phase internal transmission unit.

[0013] Three voltage detectors are installed on the outside of one side of the three-phase common enclosure, and the three voltage detectors are connected to the inside of the three-phase common enclosure.

[0014] A density relay is installed on the outside of the other side of the three-phase common enclosure, and the density relay is connected to the inside of the three-phase common enclosure;

[0015] A grounding terminal is installed on the outside of the other side of the three-phase common enclosure, and the grounding terminal is located below the density relay.

[0016] Furthermore, the three-phase internal transmission unit includes a first-phase transmission, a second-phase transmission, a third-phase transmission, a first insulating rod, a second insulating rod, and a third insulating rod. One end of the first insulating rod is connected to the output shaft of the manual operation unit. The other end of the first insulating rod is connected to one end of the second insulating rod via the first-phase transmission. The other end of the second insulating rod is connected to one end of the third insulating rod via the second-phase transmission. The other end of the third insulating rod is connected to the third-phase transmission. The first-phase transmission, the second-phase transmission, and the third-phase transmission have the same structure.

[0017] Furthermore, the first phase transmission includes a first spline, a first transmission gear, a first rack, a first sliding contact, a first contact seat, a first spring contact finger, a first shield, a first support conductor, and a first transition conductor. One end of the first spline is connected to one end of the first insulating rod, and the other end of the first spline is connected to one end of the second insulating rod. The first transmission gear is sleeved in the middle of the first spline and is located inside the first support conductor. The first support conductor is installed outside the first sliding contact and is installed to a basin-type insulator through the first transition conductor. The first transmission gear meshes with the first rack, and the first rack is installed on one side of the first sliding contact. The first spring contact finger is installed at the end of the first support conductor, and a first shield is installed at each end of the first support conductor.

[0018] Furthermore, an isolation break A is formed between the first sliding contact and the first contact seat.

[0019] Furthermore, the manual operation unit includes a manual operation mechanism housing, a manual operation hole cover, a circuit breaker indicator, a breather, an output shaft, an auxiliary switch, a transmission crank arm, a manual crank handle, a lead screw, a lead nut, a mounting bracket, a rotating shaft, and two slotted plates. The manual operation mechanism housing is externally mounted with the manual operation hole cover, the circuit breaker indicator, and the breather. The manual operation hole cover and the circuit breaker indicator are located on the same side of the manual operation mechanism housing. The mounting bracket is internally mounted with two slotted plates arranged in parallel. A rotating shaft is located at the center of each slotted plate, meshing with the output shaft. The bottom of the output shaft passes through the manual operation mechanism housing and connects to a first insulating rod. The manual operation hole cover plate is used in conjunction with the manual crank handle. One end of the manual crank handle passes through the manual operation mechanism housing and is connected to one end of the lead screw. The other end of the lead screw is installed on the inner wall of the manual operation mechanism housing. The middle part of the lead screw is located between two slot plates. The lead screw is provided with a lead screw nut. A cylinder is installed at the upper and lower ends of the lead screw nut. The cylinder at the upper end of the lead screw nut is slidably connected to a slot plate and then installed on the top of the mounting frame. The cylinder at the lower end of the lead screw nut is slidably connected to a slot plate and then installed on the bottom of the mounting frame. The cylinder at the lower end of the lead screw nut is in contact with one end of the transmission crank arm. The other end of the transmission crank arm is connected to one end of the auxiliary switch. The other end of the auxiliary switch is connected to the open / close indicator.

[0020] Furthermore, the transmission crank arm includes a guide plate, a rotating pin, a fixed pin, a connecting block, a screw, a crank arm body, a mounting pin, a spherical bearing, a fixed shaft pin, and fasteners. The guide plate contacts the cylinder at the lower end of the nut. A fixed shaft pin is sleeved in the middle of the guide plate, and the fixed shaft pin is used for the guide plate to rotate horizontally around it. A rotating pin is installed at one end of the guide plate. The rotating pin is installed into the groove of the connecting block through the fixed pin. One side of the connecting block is installed to one end of the screw. The other end of the screw is installed to one end of the spherical bearing. The other end of the spherical bearing is installed to one end of the crank arm body through the mounting pin. The other end of the crank arm body is installed to the central square shaft of the auxiliary switch through fasteners.

[0021] Furthermore, it also includes a shaft seal, with one end of the first insulating rod connected to the output shaft of the manual operating unit via the shaft seal.

[0022] Furthermore, the pressure relief unit includes a relief base, a protective cover, a protective plate, and several rupture discs. One side of the relief base is installed to one side of the three-phase common tank housing and is connected to the interior of the three-phase common tank housing. Several rupture discs are provided at the connection between the relief base and the three-phase common tank housing. The protective cover is installed on the other side of the relief base. A pressure relief hole is opened on one side of the protective cover, and a protective plate is installed on the pressure relief hole.

[0023] Furthermore, the opening distance of the isolation break A is 75mm.

[0024] Furthermore, the three-phase common enclosure is arranged in a straight line, and the distance between each phase is 550mm.

[0025] Compared with existing technologies, the cable termination structure with isolation break in a three-phase common gas chamber described in this invention has the following advantages:

[0026] The present invention discloses a three-phase common-chamber cable terminal structure with isolation break, which has a reasonable structure, stable performance, low manufacturing cost, low procurement management cost, low material management cost, convenient installation during the manufacturing process, simple on-site installation and testing operation, and safe and reliable operation. This three-phase common-chamber cable terminal structure with isolation break has a rated voltage of 252kV and a rated current of 4000A, is a three-phase common-box type, has a manually operated isolation break, and is arranged in a straight line. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0028] Figure 1 This is a front view of the overall structure described in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the back of the overall structure described in an embodiment of the present invention;

[0030] Figure 3 This is a vertical sectional view of the overall structure according to an embodiment of the present invention;

[0031] Figure 4 This is a cross-sectional view of the overall structure according to an embodiment of the present invention;

[0032] Figure 5 This is an enlarged schematic diagram of the first phase drive as described in an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the manual operation unit described in an embodiment of the present invention;

[0034] Figure 7This is a schematic diagram of the internal workings of the manual operation unit according to an embodiment of the present invention;

[0035] Figure 8 for Figure 7 A frontal view diagram;

[0036] Figure 9 This is a partial front view of the manual operation unit according to an embodiment of the present invention;

[0037] Figure 10 This is a partial rear view of the manual operation unit according to an embodiment of the present invention;

[0038] Figure 11 This is a schematic diagram of the transmission crank arm according to an embodiment of the present invention;

[0039] Figure 12 This is a schematic diagram of the pressure relief unit according to an embodiment of the present invention;

[0040] Figure 13 This is a schematic diagram of the overall structure arranged in a triangular pattern according to an embodiment of the present invention;

[0041] Figure 14 This is a schematic diagram of the overall structure arranged in a single line according to an embodiment of the present invention.

[0042] Explanation of reference numerals in the attached figures:

[0043] 1. Three-phase common housing; 101. Process hole; 2. Three-phase internal transmission unit; 21. First phase transmission; 211. First spline; 212. First transmission gear; 213. First rack; 214. First sliding contact; 215. First contact seat; 216. First spring contact finger; 217. First shielding cover; 218. First support conductor; 219. First transition conductor; 22. Second phase transmission; 23. Third phase transmission; 24. First insulating rod; 25. Second insulating rod; 26. Third insulating rod; 3. Manual operation unit; 31. Manual operation mechanism housing; 32. Manual operation hole cover; 33. Opening / closing indicator; 34. Breather; 35. Output shaft; 36. Auxiliary switch; 37. Transmission crank arm; 371. Guide plate; 372. Rotating pin; 373. Fixing pin; 374. Connecting block; 375. Screw; 376. Crank arm body; 377. Mounting pin; 378. Spherical bearing; 379. Fixing shaft pin; 38. Manual crank handle; 39. Lead screw; 310. Lead nut; 311. Mounting bracket; 312. Rotating shaft; 313. Slot plate; 4. Pressure relief unit; 41. Release base; 42. Protective cover; 43. Protective plate; 44. Rupture disc; 45. Pressure relief hole; 5. Molecular sieve; 6. Dry cable terminal; 7. Basin insulator; 8. Voltage detector; 9. Density relay; 10. Grounding terminal; 11. Shaft seal. Detailed Implementation

[0044] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0045] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0048] like Figures 1 to 13As shown, a three-phase common-chamber cable terminal structure with an isolation break includes a three-phase common-box housing 1, an isolation break A, a three-phase internal transmission unit 2 (the three-phase internal transmission unit 2 includes a first-phase transmission 21, a second-phase transmission 22, a third-phase transmission 23, a first insulating rod 24, a second insulating rod 25, and a third insulating rod 26; the first-phase transmission 21 includes a first spline 211, a first transmission gear 212, a first sliding contact 214, a first contact seat 215, a first spring contact finger 216, a first shield 217, a first support conductor 218, and a first transition conductor 219), and a manual operation unit 3 (including a manual operation mechanism housing 31, a manual operation hole cover 32, and opening / closing fingers). The components include an indicator 33, a respirator 34, an output shaft 35, an auxiliary switch 36, a transmission crank arm 37, a manual crank handle 38, a lead screw 39, a lead nut 310, a mounting bracket 311, a rotating shaft 312, and two slotted plates 313. The transmission crank arm 37 includes a guide plate 371, a rotating pin 372, a fixing pin 373, a connecting block 374, a screw 375, a crank arm body 376, a mounting pin 377, a spherical bearing 378, a fixing shaft pin 379, and fasteners. The pressure release unit 4 includes a release base 41, a protective cover 42, a protective plate 43, and a rupture disc 44. The components include a molecular sieve 5, a dry cable terminal 6, a basin-type insulator 7, a voltage detector 8, a density relay 9, a grounding terminal 10, and a shaft seal 11. Molecular sieve 5 is used to absorb gas moisture and gas impurities. Electroscope 8 and density relay 9 are both existing technologies. Electroscope 8 and density relay 9 are both connected to an external master control. Density relay 9 is used to collect the gas pressure in the three-phase common tank housing 1 and transmit the gas pressure signal in the three-phase common tank housing 1 to the external master control. The external master control is used to monitor the gas pressure changes in the three-phase common tank housing 1.

[0049] The main technical problem solved by this invention is to provide a three-phase common-chamber cable terminal structure with isolation break, which has a reasonable structural design, stable performance, low production and manufacturing costs, low procurement and material management costs, convenient installation during production and manufacturing, simple on-site installation and testing operation, and safe and reliable operation. The cable terminal is a three-phase common-chamber type with a rated voltage of 252kV and a rated current of 4000A, with a manual operation isolation break and arranged in a straight line.

[0050] In a preferred embodiment of the present invention, the key design point of the three-phase internal transmission unit 2, due to the addition of the isolation break A and the three-phase common gas chamber, is to address the electric field and transmission problems of the isolation switch with limited phase-to-phase distance.

[0051] The first sliding contact 214 is installed inside the first supporting conductor 218. The first supporting conductor 218 is fixedly installed on the basin insulator 7 through the first transition conductor 219. The basin insulator 7 is installed on the three openings of the three-phase common box housing 1.

[0052] The first contact 215 is installed on the end of the dry cable terminal 6. The distance between the first contact 215 and the first shield 217 is the isolation break A. The first shield 217 serves to improve the electric field at the break.

[0053] The two ends of the shaft seal 11 are connected to the output shaft of the manual operation unit 3 and the three-phase internal transmission unit 2, respectively. The three-phase internal transmission unit 2 drives the first transmission gear 212 of each phase to rotate. The first transmission gear 212 drives the first sliding contact 214 to move axially through the first rack 213, thereby realizing the opening and closing of the isolation break A. The shaft seal 11 plays a sealing role, transmitting external rotation to the interior of the three-phase common housing 1.

[0054] The voltage detector 8, density relay 9, and grounding terminal 10 are installed on the three-phase common enclosure 1.

[0055] In a preferred embodiment of the present invention, the three-phase common enclosure 1 is integrally welded. The phase-to-phase and phase-to-ground distances are crucial. The phase-to-phase distances are ensured by machining processes, while the phase-to-ground distances are ensured by welding fixtures. Process holes 101 are added to the design of the three-phase common enclosure 1, improving installation accuracy and reducing product assembly workload. This ensures the phase spacing of the product is aligned. The structure has undergone electric field and strength simulation calculations and passed a water pressure burst test.

[0056] In a preferred embodiment of the present invention, the isolation break A is selected with a spacing of 75mm, and a shield is installed at the break end to improve the electric field, meeting the requirements of rated lightning impulse withstand voltage of 550kV+103kV and rated short-time power frequency withstand voltage of 230kV+73kV. The first sliding contact 214 adopts a two-turn spring contact finger (first spring contact finger 216), each spring contact finger having 86 turns, meeting the temperature rise requirement of 4400A current carrying capacity. A first rack 213 is fixedly installed on the first sliding contact 214. A first transmission gear 212 is installed on the first support conductor 218. The first transmission gear 212 can control the first sliding contact 214 to slide inside the first support conductor 218 by meshing with the first rack 213. The first sliding contact 214 is electrically connected to the first supporting conductor 218 through the first spring contact finger 216. The three phases (first phase drive 21, second phase drive 22, and third phase drive 23) are connected through insulating rods (first insulating rod 24, second insulating rod 25, and third insulating rod 26) and connected to a mechanism located outside the three-phase common housing 1. The three-phase internal transmission unit 2 is located inside the three-phase common housing 1, which avoids the influence of the external environment on the components, greatly extends the service life, and reduces safety hazards.

[0057] In a preferred embodiment of the present invention, the manual operating unit 3 can open and close the isolation break via a dedicated handle. The manual operating unit 3 has an opening / closing indicator, an anti-accidental operation padlock, a manual opening indicator, and opening / closing limit functions.

[0058] In a preferred embodiment of the present invention, the three-phase cable terminals are arranged in a straight line with a phase spacing of 550mm. Based on GB / T 22381-2017 cable connectors, a dry-type cable terminal 6 is selected, with a maximum external dimension of Φ500mm, meeting the arrangement requirements. The three-phase common gas chamber structure means that the cable terminal module only needs one explosion-proof device (pressure relief unit 4) and a density relay 9, reducing product costs.

[0059] Example 1

[0060] 1. The three-phase common-enclosure housing 1 adopts a three-phase common-enclosure structure welded as a single unit. The phase-to-phase and phase-to-ground distances are crucial. The phase-to-phase distances are ensured by machining processes. When using existing welding fixtures, the phase-to-ground distance must also be guaranteed. The design of the three-phase common-enclosure housing 1 incorporates process holes 101, which have strict positional tolerance limits. By ensuring the positional relationship between the three phases when using existing positioning fixtures, installation accuracy is improved, and the product assembly workload is reduced. This ensures the phase-to-phase and phase-to-ground distances of the product. The structure has undergone electric field and strength simulation calculations and passed a water pressure burst test.

[0061] 2. For example Figure 3 As shown, the first shielding cover 217 is set at both ends of the first support conductor 218 to match the hemispherical shape of the first contact seat 215, which improves the electric field distribution of the isolation break A. The electric field simulation calculation value of the isolation break A in the open and closed positions is less than the criterion recommended by the State Grid through optimization by finite element analysis software (ANSYS 15.0).

[0062] 3. For example Figures 4-5 As shown in the detailed drawing of the three-phase internal transmission unit 2, the three-phase internal transmission unit 2 uses epoxy resin cast insulating rods for inter-phase transmission. The insulating rods are connected by splines, which are also connected to gears, driving the gears to rotate. The gears mesh with the rack, driving the sliding contacts to move linearly.

[0063] Specifically, the output shaft of manual operation unit 3 rotates, causing the epoxy resin-cast insulating rod to rotate. The epoxy resin-cast insulating rod then rotates the spline, which in turn rotates the gear. The gear meshes with the rack of the sliding contact, driving the sliding contact to slide within the supporting conductor. Simultaneously, the spline transmits the transmission to the next phase through the next-stage epoxy resin-cast insulating rod, thus achieving linear sliding of the three-phase sliding contacts.

[0064] 4. For example Figures 6-11As shown in the detailed drawing of the manual operation unit 3, when manual operation is required, the padlock should be opened first, followed by opening the manual operation hole cover 32. Insert the special handle into the operation hole under the manual operation hole cover 32, and cranking the special handle will rotate the output shaft 35. Through the shaft seal 11 and the three-phase internal transmission unit 2, this will drive the first sliding contact 214 to move linearly, thus opening and closing the isolation break A. The manual operation unit 3 is also equipped with an opening / closing indicator 33 to display the opening / closing status, and a padlock hole for users to install an anti-accidental operation padlock to prevent accidents caused by misoperation.

[0065] When manually operating the disconnect switch, the manual operation hole cover 32 of the manual operation unit 3 must be opened first.

[0066] Insert the manual crank handle 38 into the manual operation unit 3, and crank the lead screw 39 to rotate. The lead screw 39 drives the lead nut 310 to move linearly. The linear motion of the lead nut 310 pushes the slotted plate 313 to rotate. The slotted plate 313 drives the rotating shaft 312 to rotate. The rotation of the rotating shaft 312 drives the output shaft 35 to rotate, thus realizing the rotation of the output shaft 35 of the manual crank handle 38 driving mechanism. While rotating, the slotted plate 313 drives the transmission crank arm 37 to move. The movement of the transmission crank arm 37 drives the auxiliary switch 36 to rotate (the cylindrical part of the lead nut pulls the guide plate 371 in the transmission crank arm 37, causing the crank arm body 376 to swing 90°). The main shaft of the auxiliary switch 36 is connected to the opening and closing indicator, realizing the opening and closing indicator 33 displaying the position of the mechanism.

[0067] 5. For example Figure 12 As shown, the pressure relief unit 4 is a protection module for the equipment. When the equipment malfunctions, the internal pressure will rise rapidly. To protect the equipment from damage, the rupture disc 44 of the pressure relief unit 4 will rupture when it reaches the design pressure, allowing the high-pressure gas inside to escape along the pressure relief hole. The protective cover 42 can effectively control the gas to escape along the pressure relief hole after the rupture, preventing injury to personnel and equipment. The protective plate 43 can prevent foreign objects from accumulating inside the protective cover 42.

[0068] Molecular sieve 5 is mainly composed of aluminum hydroxide, water glass, and alkali metals. It has a spherical shape with a diameter of 4-6 mm and possesses strong adsorption capacity, effectively adsorbing SF6 arc decomposition products and moisture to keep it dry.

[0069] 6. A straight-line arrangement of three-phase cable terminals reduces equipment size, saves installation space, and facilitates on-site cable connection. With a straight-line arrangement, all three phases can be operated at the front end. Early products featured a triangular arrangement, which was inconvenient to install due to space limitations during on-site connection and required more reserved installation space. Figures 13-14 This diagram shows two different layout options for the space.

[0070] This invention relates to a three-phase common-chamber cable terminal structure with an isolation break, applicable to a rated voltage of 252kV, a rated current of 4000A, a three-phase common-chamber type, with a manually operated isolation break, and arranged in a straight line. According to Q / GDW 13097.1-2018 "126kV~550kV Gas-Insulated Metal-Enclosed Switchgear Procurement Standard Part 1: General Technical Specifications", cable terminals should be equipped with removable connecting conductors to isolate the cable from the GIS during insulation testing. There is a market demand for a cable terminal with an isolation break function. Based on this market demand, this invention proposes a novel cable terminal with an isolation break to meet user requirements. This cable terminal has a reasonable structural design, stable performance, low manufacturing cost, low procurement management cost, low material management cost, convenient installation during manufacturing, simple on-site installation and testing operation, and safe and reliable operation.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-phase common-chamber cable termination structure with an isolation break, characterized in that: include: A three-phase common enclosure housing (1) is provided with three process holes (101) on its surface. The three process holes (101) are used to install basin insulators (7). The three-phase common enclosure housing (1) is used as an installation carrier. Three-phase internal drive unit (2), the three-phase internal drive unit (2) is installed inside the three-phase common housing (1), the three-phase internal drive unit (2) is used to realize the opening and closing operation of the disconnecting switch; Manual operation unit (3), the manual operation unit (3) is installed on one side of the three-phase common housing (1), and the output shaft (35) of the manual operation unit (3) passes through the three-phase common housing (1) and is connected to one end of the three-phase internal transmission unit (2); Pressure relief unit (4), the pressure relief unit (4) is installed on the outside of the other side of the three-phase common tank housing (1), and the pressure relief unit (4) is connected to the inside of the three-phase common tank housing (1); Molecular sieve (5) is installed inside the other side of the three-phase common box shell (1), and the molecular sieve (5) corresponds to the pressure relief unit (4); Three dry cable terminals (6) are installed at the bottom of the three-phase common housing (1) respectively, and all three dry cable terminals (6) are connected to the three-phase internal transmission unit (2). Three basin-type insulators (7) are installed on the outside of one side of the three-phase common box housing (1), and the three basin-type insulators (7) are connected to the inside of the three-phase common box housing (1). All three basin-type insulators (7) are connected to the three-phase internal transmission unit (2). Three voltage detectors (8) are installed on the outside of one side of the three-phase common housing (1), and the three voltage detectors (8) are connected to the inside of the three-phase common housing (1); Density relay (9), the density relay (9) is installed on the outside of the other side of the three-phase common tank housing (1), and the density relay (9) is connected to the inside of the three-phase common tank housing (1); Grounding terminal (10), the grounding terminal (10) is installed to the outside of the other side of the three-phase common enclosure (1), and the grounding terminal (10) is located below the density relay (9); The three-phase internal transmission unit (2) includes a first-phase transmission (21), a second-phase transmission (22), a third-phase transmission (23), a first insulating rod (24), a second insulating rod (25), and a third insulating rod (26). One end of the first insulating rod (24) is connected to the output shaft (35) of the manual operation unit (3). The other end of the first insulating rod (24) is connected to one end of the second insulating rod (25) via the first-phase transmission (21). The other end of the second insulating rod (25) is connected to one end of the third insulating rod (26) via the second-phase transmission (22). The other end of the third insulating rod (26) is connected to the third-phase transmission (23). The first-phase transmission (21), the second-phase transmission (22), and the third-phase transmission (23) have the same structure. The first phase transmission (21) includes a first spline (211), a first transmission gear (212), a first rack (213), a first sliding contact (214), a first contact seat (215), a first spring contact finger (216), a first shield (217), a first support conductor (218), and a first transition conductor (219). One end of the first spline (211) is connected to one end of the first insulating rod (24), and the other end of the first spline (211) is connected to one end of the second insulating rod (25). The first transmission gear (212) is sleeved in the middle of the first spline (211). 2) Located inside the first support conductor (218), the first support conductor (218) is installed outside the first sliding contact (214), the first support conductor (218) is installed to a basin insulator (7) through the first transition conductor (219), the first transmission gear (212) meshes with the first rack (213) for transmission, the first rack (213) is installed on one side of the first sliding contact (214), the first spring contact finger (216) is installed at the end of the first support conductor (218), and a first shield (217) is installed at each end of the first support conductor (218); The manual operation unit (3) includes a manual operation mechanism housing (31), a manual operation hole cover (32), a circuit breaker indicator (33), a breather (34), an output shaft (35), an auxiliary switch (36), a transmission crank arm (37), a manual crank handle (38), a lead screw (39), a lead screw nut (310), a mounting bracket (311), a rotating shaft (312), and two slotted plates (313). The manual operation mechanism housing (31) is externally equipped with a manual operation hole cover (32), a circuit breaker indicator (33), and a breather. The manual operation hole cover (32) and the opening / closing indicator (33) are located on the same side of the manual operation mechanism housing (31). The manual operation mechanism housing (31) is equipped with a mounting bracket (311). The mounting bracket (311) is equipped with two slotted plates (313). The two slotted plates (313) are arranged in parallel. A rotating shaft (312) is provided at the axis of the two slotted plates (313). The rotating shaft (312) meshes with the output shaft (35) for transmission. The bottom of the output shaft (35) passes through the manual operation mechanism housing (31). The manual operation hole cover (32) is connected to one end of the first insulating rod (24). The manual operation hole cover (32) is used in conjunction with the manual crank (38). One end of the manual crank (38) passes through the manual operation mechanism housing (31) and is connected to one end of the lead screw (39). The other end of the lead screw (39) is installed on the inner wall of the manual operation mechanism housing (31). The middle part of the lead screw (39) is located between two slot plates (313). The lead screw (39) is provided with a lead nut (310). One lead nut (310) is installed at each of the upper and lower ends of the lead nut (310). The cylinder at the upper end of the nut (310) is slidably connected to a groove plate (313) and installed on the top of the mounting frame (311). The cylinder at the lower end of the nut (310) is slidably connected to a groove plate (313) and installed on the bottom of the mounting frame (311). The cylinder at the lower end of the nut (310) is in contact with one end of the transmission crank arm (37). The other end of the transmission crank arm (37) is connected to one end of the auxiliary switch (36). The other end of the auxiliary switch (36) is connected to the opening and closing indicator (33). An isolation break A is formed between the first sliding contact (214) and the first contact seat (215), and the opening distance of the isolation break A is 75mm; The three-phase common enclosure (1) is arranged in a straight line, and the spacing between each phase is 550mm; The transmission crank arm (37) includes a guide plate (371), a rotating pin (372), a fixing pin (373), a connecting block (374), a screw (375), a crank arm body (376), a mounting pin (377), a spherical bearing (378), a fixing pin (379), and fasteners. The guide plate (371) contacts the cylinder at the lower end of the nut (310). The fixing pin (379) is sleeved in the middle of the guide plate (371). The fixing pin (379) is used for the guide plate (371) to rotate horizontally around it. A rotating pin (372) is installed at one end of the connecting block (374) via a fixing pin (373). The rotating pin (372) is installed into the groove of the connecting block (374) via a fixing pin (373). One side of the connecting block (374) is installed to one end of the screw (375). The other end of the screw (375) is installed to one end of the spherical bearing (378). The other end of the spherical bearing (378) is installed to one end of the crank arm body (376) via a mounting pin (377). The other end of the crank arm body (376) is installed to the central square shaft of the auxiliary switch (36) via a fastener.

2. The cable termination structure with isolation break in a three-phase common gas chamber according to claim 1, characterized in that: It also includes a shaft seal (11), one end of the first insulating rod (24) is connected to the output shaft (35) of the manual operating unit (3) via the shaft seal (11).

3. The cable termination structure with isolation break in a three-phase common gas chamber according to claim 1, characterized in that: The pressure relief unit (4) includes a relief base (41), a protective cover (42), a protective plate (43), and a rupture disc (44). The relief base (41) is installed on one side of the three-phase common tank housing (1) and is connected to the inside of the three-phase common tank housing (1). A rupture disc (44) is provided at the connection between the relief base (41) and the three-phase common tank housing (1). The protective cover (42) is installed on the other side of the relief base (41). A pressure relief hole (45) is opened on one side of the protective cover (42), and a protective plate (43) is installed on the pressure relief hole (45).

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