Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/662—Housings or protective screens
  • H01H33/66207—Specific housing details, e.g. sealing, soldering or brazing
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/662—Housings or protective screens
  • H01H33/66207—Specific housing details, e.g. sealing, soldering or brazing
  • H01H2033/6623—Details relating to the encasing or the outside layers of the vacuum switch housings
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/666—Operating arrangements

Definitions

• the invention relates to a load switch for voltages above 1 kV with a vacuum interrupter, the contacts of which are closed or opened by means of a switching mechanism, the vacuum interrupter enclosing the switching contacts lying in vacuum with metallic end plates and a cylindrical housing middle part made of electrical Insulating material which is surrounded by a dielectric medium.
• Such load switches are e.g. Known as switch disconnectors in railway operations.
• the vacuum interrupter in the switch-on position with the switching mechanism housed in an insulating material housing is electrically shunted with the main current path designed for the full nominal current of the device.
• the main contacts When switching off, the main contacts first open without current and commutate the current to the series connection of vacuum switching chamber and auxiliary switching point, which has an actuating fork.
• the vacuum interrupter is quickly actuated using a tilting mechanism and the switch-off arc occurring inside the interrupter chamber is safely extinguished in the first zero current passage without any external appearance.
• vacuum interrupters or -ka mern used relatively have large dimensions and are associated with high manufacturing costs. For this reason, vacuum interrupters of a lower voltage range than that for which the switch is designed have been used for some time. As a result, both the dimensions and the manufacturing costs can be reduced, the active part in the vacuum interrupter generally permitting such use.
• the vacuum interrupters are placed in a medium with higher dielectric strength.
• Insulating oil such as mineral or silicone oil, various esters or an insulating gas such as sulfur hexafluoride (SF 6 ) are used. These media displace the air in the vicinity of the vacuum interrupters and because they have a high dielectric strength, an external flashover is prevented.
• SF 6 sulfur hexafluoride
• the German utility model G 93 14 754 Ul discloses a vacuum interrupter with an encapsulation resistant to internal pressure.
• Encapsulating this vacuum switching tube consists of an inner layer made of hard plastic foam and an outer burst-proof jacket.
• the inner layer which is preferably made of a polyurethane foam, is uniformly porous in order to enable the best possible thermal insulation according to the teaching of this document, so that in the event of a fault no temperature sufficient to ignite the surrounding gas can be reached.
• the burst-proof jacket is designed as a winding body and consists of threads or tapes that are impregnated with a hardened plastic. It is formed close to the foam layer and dimensioned so that it can absorb the bursting force that occurs in the event of a fault within the vacuum interrupter.
• the casing of the tube also contains a firmly foamed plastic material, the properties of which can be impaired by aging.
• embrittlement or detachment of the foam layer from the outer casing of the tube can occur.
• disassembly of this encapsulated vacuum interrupter is only possible if the casing is destroyed.
• the invention is therefore based on the object of providing a load switch which can be safely used over a long period of time without control and can also be dismantled.
• the housing is surrounded by a prefabricated sleeve which engages behind the edges of the two end plates and consists of an elastomer material with high dielectric strength, which is pressed onto the housing without gaps. It is of great advantage here that, due to the elastic properties of the sleeve, no gap remains on the periphery of the housing. An external rollover on the vacuum interrupter via such an air gap is therefore not possible.
• Front plates of the vacuum interrupter can be gripped behind by the cuff and the path for a possible rollover can be significantly lengthened. This prevents this case even more reliably.
• the load switch according to the invention has numerous other advantages.
• the load switch can therefore be used in continuous operation for many years without having to check the sleeve acting as a dielectric medium.
• Another advantage is that the assembly of the circuit breaker according to the invention is considerably simplified. So training with a prefabricated cuff a pre-assembly of the arrangement, which is why no effort for a final assembly or a filling is necessary, for example, high up on the mast. Since no liquid or gaseous medium is handled, the effort for the transport and installation of the circuit breaker according to the invention is considerably simplified.
• the circuit breaker according to the invention is easy to manufacture and allows disassembly if necessary.
• formerly ⁇ e ⁇ n interrupter vacuum can be kept low, the space required and the cost.
• the dimensions of the sleeve are selected such that the sleeve applies a preload to the vacuum interrupter chamber reliably prevents an air gap between the sleeve and the housing of the vacuum interrupter chamber.
• the relatively large dimensional tolerances of the vacuum interrupter can thus also be compensated for. This further increases the reliability of the circuit breaker.
• a complementary pressure housing made of insulating material is provided on the outside of the sleeve, which prestresses the outer circumference of the sleeve in the elastic region. This ensures, on the one hand, that the sleeve presses firmly against the vacuum interrupter and, furthermore, that there is no air gap on the outer circumference of the sleeve, which could allow an external rollover. The possible distance for an external rollover is thereby increased to a level at which this is practically no longer possible. This further increases the operational safety and reliability of the circuit breaker. Furthermore, the vacuum interrupter is centered and fixed in the pressure housing.
• the sleeve has at least one sealing bead running in the axial direction of the pressure housing, which comes to rest in the assembly joint of the pressure housing, a sealing of the pressure housing against external influences is also achieved. This reliably prevents e.g. Dirt and especially water can penetrate the pressure housing. Failure of the load switch can thus be effectively avoided. Furthermore, the one-piece design of the sleeve with the sealing bead facilitates the assembly of the arrangement.
• the sealing bead also has a thickening that can be squeezed in the assembly joint of the pressure housing, the reliability of this seal on the pressure housing is further increased.
• the cuff has at least one recess for receiving material of the cuff displaced under the pressure load. It is thereby achieved that the cuff fits cleanly on the peripheral surface of the vacuum interrupter chamber without the cuff being damaged by the applied compressive forces. This further increases the reliability of the circuit breaker.
• the at least one recess is advantageously designed as a circumferential annular groove in the inner periphery of the sleeve. This results in an even pressure distribution over the entire circumference of the vacuum interrupter.
• the length of the vacuum interrupter chamber can be adjusted in the assembled state without the material of the cuff being damaged, since it can escape into the at least one pocket can. The reliability of the sleeve and thus the operational safety of the load switch is increased.
• the at least one pocket is also ring-shaped, a uniform distribution of the pressure load on the end face of the cuff is achieved.
• the cuff according to the invention is preferably made of EPDM (ethylene-propylene terpolymer) or silicone rubber, which have good elastic properties and are not compressible. Such materials allow a secure sealing of the interface between the vacuum interrupter and the sleeve or between the sleeve and the pressure housing of the load switch. A rollover can thus be safely avoided.
• EPDM ethylene-propylene terpolymer
• silicone rubber which have good elastic properties and are not compressible.
• the load switch is designed as a load break switch, in which a visible isolating path is arranged in series with the vacuum interrupter, a visual check can also be carried out from a greater distance in order to determine whether the load switch is closed. If a circuit is connected in parallel to the vacuum interrupter or parallel to the vacuum interrupter / visible isolating section when the load switch is switched on, the vacuum tube is relieved when the load switch (switch disconnector) is in the closed state.
• This has the advantage that the vacuum interrupter is only acted upon by the high voltages present during the switching operations.
• a continuous current can be conducted which is higher than the nominal current of the switching chamber or the series connection of vacuum switching chamber and visible isolating section. This significantly increases the lifespan of the circuit breaker.
• Figure 1 is a sectional view of a circuit breaker according to the invention, with a section in the parting plane of the pressure housing on the left side of the main axis and a section in another plane through a housing half of the pressure housing to the right of the main axis; and
• FIG. 2 shows a simplified sectional illustration along the line A-A in FIG. 1.
• a load switch 1 has a pressure housing with two housing halves 11 and 12, which are made of insulating material and are essentially mirror images.
• the housing halves 11 and 12 there are, inter alia, a vacuum interrupter 2 and a switching mechanism 3 arranged.
• the arrangement and function of the vacuum interrupter 2 and the switching mechanism 3 correspond to the known designs, which is why a detailed explanation is given here.
• the vacuum interrupter 2 has switching contacts inside, which are closed or opened by the switching mechanism 3.
• the switching mechanism 3 is formed with an eccentric actuating element 31, which acts on a movable contact 21 of the vacuum switching chamber 2.
• the vacuum interrupter chamber 2 has a fixed contact 22 which is arranged opposite the movable contact 21.
• the vacuum interrupter 2 also has a housing 23 which is provided with metallic end plates 24 and 25 which close off a cylindrical housing middle part 26.
• the middle housing part 26 is made of electrically insulating material. A high vacuum prevails within the vacuum interrupter chamber 2, which ensures a safe arc interruption when switched off and a safe voltage hold when switched off.
• a sleeve 4 made of EPDM (ethylene-propylene terpolymer) is arranged around the vacuum interrupter 2.
• the sleeve 4 is designed such that it encompasses the edges of the two end plates 24 and 25 of the vacuum interrupter 2.
• the dimensions of the sleeve 4 are selected so that tolerance deviations of the vacuum interrupter chamber 2 can be compensated for and the sleeve 4 is nevertheless pretensioned on the circumferential surface of the vacuum um-Sehaltkarmmer 2 is present. As a result, there is no continuous air gap between the end plates 24 and 25.
• the sleeve 4 is in turn encompassed and biased by the housing halves 11 and 12 of the load switch 1. Because of the bias voltage is between the sleeve 4 and the mounted half housings 11 and 12 before, no air gap which would be a external flashover of the voltage between the end plates 24 and 25 of the vacuum Weg Weg- -erlauben ⁇ ?.
• the sleeve 4 has ring-shaped shields 41 which are received in corresponding cutouts in the housing halves 11 and 12.
• the flap 41 is used in a known manner to extend the path (creepage distance) along the surface.
• the sleeve 4 also has four recesses 42 which are arranged on the inner circumferential surface and have an annular shape.
• the cutouts 42 allow the material of the cuff 4 to escape into the spaces formed thereby . In this way, damage to the sleeve 4 is prevented and a good seal of the interface between the sleeve 4 and the vacuum interrupter 2 is achieved.
• annular pocket 43 is also formed. Since vacuum interrupters 2 have relatively large length tolerances, length adjustment or positioning of the vacuum interrupter 2 in the load switch 1 may be necessary. In order to allow the necessary deformation of the sleeve 4 in this end region, the annular pocket 43 serves as a chamber for a volume compensation of the displaced material.
• the sleeve 4 also has a sealing bead 44 with a thickening 45. These are each arranged on the two assembly joints of the housing halves 11 and 12 of the circuit breaker 1 for sealing against external influences.
• the thickening 45 is received in appropriately designed recesses or grooves on the joint surfaces of the housing halves 11 and 12 and squeezed when the housing halves 11 and 12 are closed.
• the sealing bead 44 with the thickening 45 has a length which essentially corresponds to the total length of the sleeve 4. However, it can also be formed in one piece with the sleeve 4 as a round cord for sealing the pressure housing in the entire assembly joint area of the housing halves 11 and 12.
• the load switch is used as a switch disconnector and arranged in series with a visible isolating path.
• a main current path designed for the continuous operating current is connected in parallel to the vacuum interrupter and an auxiliary switching point in series therewith, as a result of which the vacuum tube is relieved when the load-break switch is switched on.
• the main contact is first opened in a known manner, as a result of which the voltage is passed completely via the vacuum interrupter 2. Then the contacts 21 and 22 of the vacuum interrupter 2 are disconnected and the connection is completely interrupted without arcing in the load switch 1.
• the dimensions and shape of the sleeve 4 can vary depending on the construction and type of the vacuum interrupter 2. In any case, it is essential that the sleeve 4 rests against the vacuum interrupter 2 in such a way that no air gap between them is possible.
• the cuff 4 does not have to be formed with shields 41, but can also have a differently designed or smooth outer circumferential surface if the safety of the load switch 1 permits it, for example due to low voltages present.
• the cutouts 42 in the sleeve 4 have semicircular cross sections and are formed at four locations around the vacuum interrupter 2. Both the shape and the number of annular recesses 42 can differ from this. Furthermore, it is also possible, instead of the embodiment shown, to provide the cutouts 42 with an annular shape at certain points on the inner circumferential surface of the sleeve 4.
• the pocket 43 in the cuff 4 can also be provided on both end faces.
• the shape and number of the pocket 43 can also vary in a manner similar to the recesses 42.
• the sleeve 4 can be used in any way in connection with vacuum interrupters 2, which also includes other switching elements as switch disconnectors. Use in circuit breakers and the like is also conceivable.
• the pressure housing can also consist of more than two housing parts, the number of sealing beads 44 being adapted to the number of assembly joints.
• a continuous current or main current contact system can also be provided, which allows the load switch 1 to be to design a specific vacuum interrupter 2 for different nominal or continuous currents.
• the invention thus creates a load switch 1 for voltages in the kV range with a vacuum interrupter 2, which is encompassed without a gap by a sleeve 4 made of elastomer material with high dielectric strength.
• the cuff 4 is in turn clamped by the housing halves 11 and 12 of the load switch 1.
• an external flashover of the high voltage between the end plates 24 and 25 of the vacuum interrupter 2 is effectively prevented during the switching process, without the need for liquid or gaseous media.
• this does not require a lot of control and the load switch is harmless to the environment.

Landscapes

• High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
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• Oscillators With Electromechanical Resonators (AREA)
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• Electric Clocks (AREA)
• Thermally Actuated Switches (AREA)

Priority Applications (13)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (1)

Family

ID=7803719

Family Applications (1)

Country Status (18)

Cited By (3)

Families Citing this family (4)

Citations (8)

Family Cites Families (1)

• 1996
  • 1996-08-26 DE DE19634451A patent/DE19634451C1/de not_active Expired - Lifetime
• 1997
  • 1997-08-25 PT PT97944787T patent/PT920705E/pt unknown
  • 1997-08-25 WO PCT/EP1997/004617 patent/WO1998009310A1/de active IP Right Grant
  • 1997-08-25 TR TR1999/00436T patent/TR199900436T2/xx unknown
  • 1997-08-25 RS YUP-102/99A patent/RS49698B/sr unknown
  • 1997-08-25 DE DE59701481T patent/DE59701481D1/de not_active Expired - Lifetime
  • 1997-08-25 AU AU46183/97A patent/AU4618397A/en not_active Abandoned
  • 1997-08-25 DK DK97944787T patent/DK0920705T4/da active
  • 1997-08-25 AT AT97944787T patent/ATE191990T1/de active
  • 1997-08-25 EP EP97944787A patent/EP0920705B2/de not_active Expired - Lifetime
  • 1997-08-25 SK SK238-99A patent/SK282723B6/sk not_active IP Right Cessation
  • 1997-08-25 CZ CZ1999585A patent/CZ288889B6/cs not_active IP Right Cessation
  • 1997-08-25 CA CA002263881A patent/CA2263881C/en not_active Expired - Lifetime
  • 1997-08-25 HU HU9903117A patent/HU222705B1/hu active IP Right Grant
  • 1997-08-25 PL PL97331997A patent/PL187251B1/pl unknown
  • 1997-08-25 RU RU99105735/09A patent/RU2188474C2/ru active
  • 1997-08-25 ES ES97944787T patent/ES2144880T5/es not_active Expired - Lifetime
• 1999
  • 1999-06-30 HK HK99102763A patent/HK1017768A1/xx not_active IP Right Cessation
• 2000
  • 2000-04-20 GR GR20000400964T patent/GR3033287T3/el unknown

Patent Citations (8)

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