31.5 kA short-time withstand current vacuum switch tube for increasing creepage distance along surface

Abstract

The utility model discloses a 31.5 kA short-time withstand current vacuum switch tube for increasing creepage distance along a surface, which comprises a vacuum switch tube main body, the vacuum switch tube main body is composed of a ceramic shell, a movable conducting rod, a static conducting rod, a movable end sealing cover, a static end sealing cover, a corrugated pipe, a shielding cover, a movable contact and a static contact, the ceramic shell is of a cylindrical structure, the length of the ceramic shell is 130 + / -0.2 mm, and the width of the corrugated pipe is larger than that of the movable end sealing cover. The outer side face of the porcelain shell is of a corrugated structure, the corrugated structure is provided with wave crests and wave troughs, the diameter of the wave crests is 92 mm, the diameter of the wave troughs is 83 mm, and the creepage distance, formed by the wave crests and the wave troughs, of the outer side face of the porcelain shell is 244 mm. According to the utility model, through the arrangement of the overall structure, the creepage distance is increased, so that the vacuum switch tube can be used in an environment with an altitude of 1000 meters or below, the application range of the vacuum switch tube is expanded, and the stability of the vacuum switch tube is improved.

Description

Technical Field

[0001] The utility model relates to a 31.5kA short-time withstand current vacuum switch tube with improved surface creepage distance. Background Art

[0002] Vacuum interrupters, also known as vacuum interrupters, are core components of medium- and high-voltage power switches. Their primary function is to rapidly extinguish arcs and suppress current flow in medium- and high-voltage circuits after power is disconnected, thanks to the excellent insulation properties of the vacuum within the tube, thereby preventing accidents and incidents. They are primarily used in power transmission and distribution control systems, as well as in power distribution systems for metallurgy, mining, petroleum, chemical engineering, railways, broadcasting, communications, and industrial high-frequency heating. They offer advantages such as energy conservation, material conservation, fire and explosion resistance, compact size, long lifespan, low maintenance, reliable operation, and zero pollution. Vacuum interrupters are categorized by application into circuit breaker interrupters and load switch interrupters. Circuit breaker interrupters are primarily used in substations and power grid facilities within the power sector, while load switch interrupters are primarily used by end users of the power grid.

[0003] Existing vacuum switch tubes, due to space limitations on the insulation distance between the moving and static terminals, have a relatively short creepage distance within the metallized ceramic shell, resulting in lower insulation test standards. For example, early vacuum switch tubes were tested to a power frequency withstand voltage standard of 42 kV and a lightning impulse withstand voltage standard of 75 kV. The outer diameter of the insulating ceramic shell was 88 mm, and the creepage distance was 194 mm. During power frequency withstand voltage testing and operational use, low atmospheric pressure (or altitudes above 500 meters) and high humidity can easily cause flashovers, which can even cause breakdown of the ceramic shell in severe cases, resulting in product damage and grid failures. Consequently, existing vacuum switch tubes have significant limitations, necessitating the development of a new type of vacuum switch tube. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a 31.5kA short-time withstand current vacuum switch tube which is easy to use and has a compact structure. By adjusting the overall structure and appearance, the creepage distance reaches 244mm, which can meet the needs of use in environments below 1000 meters above sea level. The utility model has practicality and wide application and can improve the creepage distance.

[0005] In order to solve the above problems, the present invention adopts the following technical solutions:

[0006] A 31.5kA short-time withstand current vacuum switch tube with improved creepage distance comprises a vacuum switch tube body, which is composed of a porcelain shell, a dynamic conductive rod, a static conductive rod, a dynamic end cover, a static end cover, a bellows, a shielding cover, a dynamic contact, and a static contact. The overall length of the vacuum switch tube body is 175±1.50mm. The dynamic conductive rod and the static conductive rod are arranged at both ends of the porcelain shell. The ends of the dynamic conductive rod and the static conductive rod extending into the interior of the porcelain shell are respectively mounted with a dynamic contact and a static contact. The dynamic contact and the static contact are arranged in the shielding cover. The porcelain shell is a cylindrical structure with a length of 130±0.2mm. The outer surface of the porcelain shell adopts a corrugated structure with crests and troughs. The diameter of the crests is 92mm, and the diameter of the troughs is 83mm. The creepage distance of the outer surface of the porcelain shell formed by the crests and troughs is 244mm.

[0007] Preferably, the moving end cover and the static end cover are respectively arranged at the two ends of the porcelain shell, a moving end support ring is provided on the inner side of the moving end cover, and a static end support ring is provided on the inner side of the static end cover. One end of the moving conductive rod passes through the middle of the moving end cover and the moving end support ring and extends into the shielding cover, and one end of the static conductive rod passes through the middle of the static end cover and the static end support ring and extends into the shielding cover; the airtightness inside the porcelain shell is increased by the moving end cover and the static end cover, the vacuum environment inside the shielding cover is improved, and the normal operation of the vacuum switch tube is ensured.

[0008] Preferably, a guide sleeve is provided on the moving conductive rod, and the guide sleeve is connected to the moving end support ring and the moving end cover; the guide sleeve guides the moving conductive rod in the direction of movement, and also increases the stability of the moving conductive rod during movement, thereby ensuring precise contact or separation between the moving contact and the static contact.

[0009] Preferably, the movable end support ring and the static end support ring both include a support portion, a clamping portion and a limiting portion; through the functions of the movable end support ring and the static end support ring, the support and limiting of the movable conductive rod and the static conductive rod are respectively achieved.

[0010] Preferably, an annular boss is provided inside the ceramic shell, and the shielding cover is limited by the annular boss, which facilitates the installation and fixation of the shielding cover and increases the stability of the shielding cover after installation.

[0011] The beneficial effects of the utility model are: easy to use, compact structure, and small space occupation. At the same time, by adjusting the overall structure and appearance, the surface creepage distance reaches 244mm, which can meet the needs of use in environments below 1,000 meters above sea level. It is practical and widely used. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art, but this does not limit the scope of protection of the present invention.

[0013] Figure 1 It is a structural diagram of the utility model;

[0014] Figure 2 It is a cross-sectional schematic diagram of the utility model;

[0015] Figure 3 This is an enlarged schematic diagram of point A of the present invention.

[0016] Among them, 1. porcelain shell, 2. dynamic conductive rod, 3. static conductive rod, 4. dynamic end cover, 5. static end cover, 6. guide sleeve, 7. dynamic end support ring, 8. bellows, 9. shielding cover, 10. dynamic contact, 11. static contact, 12. static end support ring, 13. annular boss, 14. wave crest, 15. wave trough, 16. support part, 17. locking part, 18. limiting part. DETAILED DESCRIPTION

[0017] See Figures 1 to 3 A 31.5kA short-time withstand current vacuum switch with improved creepage distance shown in FIG. includes a vacuum switch body, which is composed of a porcelain shell 1, a moving conductive rod 2, a static conductive rod 3, a moving end cover 4, a static end cover 5, a bellows 8, a shielding cover 9, a moving contact 10, and a static contact 11. The overall length of the vacuum switch body is 175±1.50mm. The moving conductive rod and the static conductive rod are arranged at both ends of the porcelain shell. The ends of the moving conductive rod and the static conductive rod extending into the interior of the porcelain shell are respectively mounted with a moving contact and a static contact. The moving contact and the static contact are arranged in the shielding cover. The porcelain shell is a cylindrical structure. The length of the porcelain shell 1 is 130±0.2mm. The outer surface of the porcelain shell adopts a corrugated structure with crests and troughs. The diameter of the crests is 92mm, and the diameter of the troughs is 83mm. The creepage distance of the outer surface of the porcelain shell formed by the crests and troughs is 244mm.

[0018] Furthermore, the dynamic end cover 4 and the static end cover 5 are respectively arranged at the two ends of the porcelain shell 1, the inner side of the dynamic end cover 4 is provided with a dynamic end support ring 7, and the inner side of the static end cover 5 is provided with a static end support ring 12. One end of the dynamic conductive rod 2 passes through the middle of the dynamic end cover 4 and the dynamic end support ring 7 and extends into the shielding cover, and one end of the static conductive rod passes through the middle of the static end cover 5 and the static end support ring 12 and extends into the shielding cover.

[0019] Furthermore, a guide sleeve 6 is provided on the movable conductive rod 2 , and the guide sleeve 6 is connected to the movable end support ring 7 and the movable end cover 4 .

[0020] Furthermore, the movable end support ring 7 and the static end support ring 12 both include a support portion 16 , a snap-fit ​​portion 17 and a limit portion 18 , and the support portion 16 , the snap-fit ​​portion 17 and the limit portion 18 are connected to form an integral structure.

[0021] Furthermore, an annular boss 13 is provided inside the ceramic shell 1 .

[0022] Furthermore, the shielding cover 9 is arranged in the porcelain shell.

[0023] Furthermore, the movable end support ring and the static end support ring are both arranged on the inner side of the porcelain shell.

[0024] Furthermore, the engaging portion 17 is fitted into the interior of the ceramic shell.

[0025] Furthermore, the short-time withstand current of the vacuum switch tube body is 31.5KA.

[0026] Furthermore, the short-circuit breaking current of the vacuum switch tube body is 31.5KA.

[0027] Furthermore, the peak withstand current of the vacuum switch tube body is 80KA.

[0028] Furthermore, the short-circuit closing current of the vacuum switch tube body is 80KA.

[0029] Furthermore, the rated voltage of the vacuum switch tube body is 12KV.

[0030] Furthermore, the rated current of the vacuum switch tube body is 1250A.

[0031] Furthermore, the rated frequency of the vacuum switch tube body is 50 Hz.

[0032] Furthermore, the peak value of the lightning impulse withstand voltage of the vacuum switch tube body is 85KV.

[0033] Furthermore, the opening distance between the static contact and the moving contact is 9±1.0 mm.

[0034] The vacuum interrupter tube of this utility model is a core component of medium- and high-voltage power switches. Its primary function is to rapidly extinguish arcs and suppress current flow in medium- and high-voltage circuits after power is disconnected, preventing accidents and unexpected events through the excellent insulation of the vacuum within the tube. It is primarily used in power transmission and distribution control systems. A vacuum interrupter tube is an electrical vacuum device that utilizes a high-vacuum operating insulating arc-extinguishing medium and a pair of contacts sealed in a vacuum to achieve the switching function of power circuits. When it interrupts a certain current, the current shrinks to the point where the moving and static contacts separate at the moment they separate. This causes a sharp increase in inter-electrode resistance and a rapid rise in temperature, ultimately leading to evaporation of the electrode metal. This simultaneously generates an extremely high electric field strength, leading to extremely strong emission and gap breakdown, generating a vacuum arc. When the power-frequency current approaches zero, the contact gap increases, and the plasma of the vacuum arc rapidly spreads. After the arc current passes zero, the medium in the contact gap rapidly changes from a conductor to an insulator, thus interrupting the current. Due to the special structure of the contacts, a suitable longitudinal magnetic field is generated across the contact gap during arcing. This magnetic field evenly distributes the arc across the contact surface, maintaining a low arc voltage. This results in a faster post-arc dielectric strength recovery rate, lower arc energy, and a lower corrosion rate for the vacuum interrupter. This improves the current-breaking capacity and service life of the vacuum interrupter.

[0035] The shielding cover of the utility model has the following functions: 1. Preventing the contacts from generating a large amount of metal vapor and liquid droplets splashing during the arcing process, which may contaminate the inner wall of the insulating shell and avoid causing the insulation strength of the vacuum switch tube porcelain shell to decrease or cause flashover.

[0036] 2. Improving the electric field distribution inside the vacuum switch tube is conducive to the miniaturization of the insulating shell of the vacuum switch tube, especially for the miniaturization of high-voltage vacuum switch tubes.

[0037] 3. Absorbs some arc energy and condenses arc products. When a vacuum interrupter interrupts a short-circuit current, the shielding system absorbs most of the heat generated by the arc, which helps improve the dielectric recovery strength between the contacts. The greater the shielding system's absorption of arc products, the greater its energy absorption, which in turn increases the interrupting capacity of the vacuum interrupter.

[0038] The function of the bellows of the utility model is to ensure that the moving electrode moves within a certain range and maintains a high vacuum for a long time, and to ensure that the vacuum switch tube has a long mechanical life.

[0039] When the vacuum circuit breaker, vacuum load switch, and vacuum contactor, assembled from vacuum switching tubes, are closed, the operating mechanism closes the two contacts (moving and static) through the movement of the movable conductive rod, completing the circuit connection. To minimize and maintain contact resistance between the two contacts and ensure good mechanical strength for the arc extinguishing chamber when subjected to dynamic and stable currents, the vacuum switch is equipped with a guide sleeve at one end of the movable conductive rod and a set of compression springs to maintain a rated pressure between the two contacts. When the vacuum switch interrupts current, the two contacts of the arc extinguishing chamber separate, generating an arc between them. The arc extinguishes when the current naturally crosses zero, completing the circuit interruption.

[0040] The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited to them. Any changes or substitutions that do not require creative work should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection defined in the claims.

Claims

1. A 31.5kA short-time withstand current vacuum switch with improved creepage distance, characterized by: The invention comprises a vacuum switch tube body, which is composed of a porcelain shell, a dynamic conductive rod, a static conductive rod, a dynamic end cover, a static end cover, a bellows, a shielding cover, a dynamic contact, and a static contact. The overall length of the vacuum switch tube body is 175±1.50mm. The dynamic conductive rod and the static conductive rod are arranged at both ends of the porcelain shell. The ends of the dynamic conductive rod and the static conductive rod extending into the interior of the porcelain shell are respectively installed with a dynamic contact and a static contact. The dynamic contact and the static contact are arranged in the shielding cover. The porcelain shell is a cylindrical structure with a length of 130±0.2mm. The outer surface of the porcelain shell adopts a corrugated structure with crests and troughs. The diameter of the crest is 92mm, and the diameter of the trough is 83mm. The creepage distance of the outer surface of the porcelain shell formed by the crests and troughs is 244mm. The short-time withstand current of the vacuum switch tube body is 31.5kA.

2. The 31.5kA short-time withstand current vacuum switch with improved creepage distance according to claim 1, characterized in that: The dynamic end cover and the static end cover are respectively arranged at the two ends of the porcelain shell. A dynamic end support ring is provided on the inner side of the dynamic end cover, and a static end support ring is provided on the inner side of the static end cover. One end of the dynamic conductive rod passes through the middle of the dynamic end cover and the dynamic end support ring and extends into the shielding cover. One end of the static conductive rod passes through the middle of the static end cover and the static end support ring and extends into the shielding cover.

3. The 31.5kA short-time withstand current vacuum switch with improved creepage distance according to claim 1, characterized in that: A guide sleeve is provided on the movable conductive rod, and the guide sleeve is connected to the movable end support ring and the movable end cover.

4. The 31.5kA short-time withstand current vacuum switch with improved creepage distance according to claim 2, characterized in that: The movable end support ring and the static end support ring both include a support portion, a clamping portion and a limiting portion.

5. The 31.5kA short-time withstand current vacuum switch with improved creepage distance according to claim 1, characterized in that: An annular boss is provided inside the porcelain shell.

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