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
  • H01H33/70—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid
  • H01H33/98—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid the flow of arc-extinguishing fluid being initiated by an auxiliary arc or a section of the arc, without any moving parts for producing or increasing the flow
  • H01H33/982—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid the flow of arc-extinguishing fluid being initiated by an auxiliary arc or a section of the arc, without any moving parts for producing or increasing the flow in which the pressure-generating arc is rotated by a magnetic field

Definitions

• the invention relates to an arc extinguishing device for a self-expanding, gas-insulated electrical switch or circuit breaker comprising:
• the object of the invention is to improve the centering of the arc in a gas-insulated circuit breaker or switch, in particular with autoexpansion and / or rotary arc, and to increase the breaking performance of the circuit breaker.
• the arc extinguishing device is characterized in that the divisional breaking chamber comprises, to the right of the contact separation zone, a left lateral surface with an envelope not adjusted for revolution, in particular convex or concave, so forming an acoustic resonator with centripetal reflection of the pressure waves, generating a convergence of the gases towards said separation zone, and that the separable contacts are arranged in the vicinity of the central zone of said breaking chamber.
• the wall of the breaking chamber has a spherical shape or a spherical sector such that the acoustic resonator has a vibration belly in the center of the sphere.
• the breaking chamber has a shape of ellipsoid arranged, such that the contacts are located substantially at the level of the two hearths in the open position of the circuit breaker. This results in better centering of the arc, in particular in the vicinity of the electrodes.
• At least one of the contacts can be fitted with a permanent magnet or an electromagnetic coil to cause the arc to rotate inside the breaking chamber.
• the wall of the breaking chamber is made of an insulating material, in particular based on epoxy resin, or any other material having a high reflection coefficient.
• FIG. 1 is an axial sectional view of a circuit breaker According to the invention, shown in the open position,
• FIG. 1 shows an electric circuit breaker 10 with a rotating arc and self-expanding, comprising an insulating casing 12, of cylindrical shape, closed at its opposite ends by bottoms 14, 16.
• the casing 12 is sealed and filled with electronegative insulating gas at high dielectric strength, such as sulfur hexafluoride.
• a divisional interrupting chamber 18 serving as a housing for a contact system 20, 22 separable and coaxial.
• the fixed contact 20 formed by a conductive tube 24 carried by the bottom 14, is equipped at its opposite end with an electrode 26 disposed opposite an annular contact surface 28 of the movable contact 22.
• the latter comprises a support tube 29 mounted for axial sliding in the casing 12 while being secured to a control rod 30 which passes through a central opening 32 in the bottom 16 with the interposition of a seal 34.
• a conductive braid 36 or any other flexible or sliding conductor provides the electrical connection between the tube 29 of the movable contact 22 and the bottom 16.
• Connection terminals 36, 38 of the pole of the circuit breaker 10 are associated with the bottoms 14, 16, made of conductive material.
• the two tubes 24, 29, fixed contacts 20 and movable 22 each comprise an internal axial exhaust duct 40, 42 and radial orifices 44, 46 allowing communication between the interior of the breaking chamber 18 and the remaining volume of the casing 12 constituting a discharge chamber 48.
• the bottom 14 is provided with a first hole 50 closed by a closure plug 52, and a second hole 54 cooperating with a safety valve formed by a bursting disc 56 in the event of abnormal overpressure inside the envelope 12.
• the two aligned tubes 24, 29 pass through the wall 58 of the interrupting chamber 18 in leaktight fashion, and the annular contact surface 28 of the sliding tube 29 cooperates by abutment in closed position of the circuit breaker with the electrode 26 of the tube 24.
• the electrode 26 constitutes an annular track for migration of the arc root.
• magnetic means in particular a permanent magnet or an electromagnetic coil 60 in the form of a cylinder, intended to generate a radial induction field in the separation zone 62 of the contacts, for ensure the rotation of the arc.
• the mechanical and electrical connection between the electrode 26 and the tube 24 is ensured by a conductive sleeve 64 coaxially surrounding the coil 60.
• the wall 58 of the divisional breaking chamber 18 has a left internal lateral surface with an envelope not adjusted for revolution around the contacts, in particular of convex or concave shape, so as to form an acoustic resonator with centripetal reflection of the waves. pressure inside the chamber 18.
• the surface of revolution is advantageously spherical or hemispherical, such that the acoustic resonator has a vibration belly in the center of the sphere.
• the annular electrode 26 of the fixed contact 20 and the mating contact surface 28 of the movable contact 22 are arranged in the vicinity of the center of the spherical chamber 18.
• the wall 58 of the divisional chamber 18 is made of an insulating material, in particular based on epoxy resin, or any other material having a high reflection coefficient.
• a deflector (not shown) made of metallic or refractory material can be placed against the internal face of the chamber 18, facing the separation zone 62 of the contacts.
• the breaking chamber 18 is supported by fixing means 68 secured to the bottom 16, as well as by the tube 24 fixed to the opposite bottom 14.
• the arc When the contacts 20, 22 are separated, at the center of the spherical breaking chamber 18, the arc extends in the zone 62 and is driven in rotation by the action of the magnetic field of the coil 60 or of the magnet.
• the heat released by the rotating arc causes an increase in pressure inside the breaking chamber 18, and a gas flow through the internal exhaust ducts 40, 42 of the contacts 20, 22 hollow towards the discharge chamber 48 in which the expansion of the compressed gas initially takes place in the breaking chamber 18.
• the centripetal reflection of the pressure waves on the internal wall 58 of the spherical chamber 18 causes the gases to converge towards the separation zone 62 of the contacts , and contributes effectively to the centering of the arc.
• FIG. 2 shows an alternative embodiment of a circuit breaker 100, in which the same references designate parts identical to those of the device in FIG. 1.
• the shape of the wall 58 of the breaking chamber 18 has been modified, and comprises a spherical sector 70 central to the right of the separation zone 62 of the contacts, extended by two opposite cylindrical portions 72, 74.
• FIG. 3 represents another variant of circuit breaker 200 with self-expansion.
• a pressure wave emitted in one of the foci F1 inside the ellipsoid is reflected by the wall 58 and focused at the other focal point F2. This results in excellent centering of the arc in the vicinity of the electrodes.
• the circuit breaker 200 of fig. 3 has been shown without magnetic arc blowing means, but it is clear that it can be equipped with a coil or a permanent magnet ensuring the rotation of the arc.
• the circuit breaker 10, 100, 200, according to one of FIGS. 1 to 3, can also be equipped with an auxiliary blowing device (not shown) with compression piston-cylinder, actuated during the displacement of the movable contact 22 to send a jet of blowing gas towards the arc zone.
• This pneumatic blowing device can be incorporated, either directly in the breaking chamber 18, or in the discharge chamber 48.
• the SF 6 circuit breaker or switch is of the rotating arc type, but without autoexpansion, comprising a single sealed envelope for housing a pair of separable contacts and a magnetic blow-out coil.
• the arc extension zone is advantageously surrounded by an internal wall having the shape of a sphere or ellipsoid, to ensure the centering of the arc along the longitudinal axis of revolution.
• the devices of FIGS. 4 to 7 show other variants of the breaking chamber 18, intended to produce focusing effects of the acoustic waves.
• the focusing elements can be constituted by a succession of 90-plane mirrors (FIG. 4), staggered along a substantially elliptical curve, or by a juxtaposition of two opposite truncated cones 92, 94 (FIG. 5).
• FIG. 6 the internal face of the wall 58 of the chamber 18 is notched by a plurality of notches 96, so as to form a Fresnel lens structure, capable of further improving the dielectric strength by increasing the creepage.
• the wall 58 is cylindrical, and the part 98 or deflector of the focusing element has the shape adapted to constitute the acoustic resonator.
• the material of the part 98 may be different from that of the wall 58, so as to ensure its protection against pollution due to the arc, and to improve the creepage distance.

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• Circuit Breakers (AREA)
• Arc-Extinguishing Devices That Are Switches (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=9304861

Family Applications (1)

Country Status (7)

Families Citing this family (12)

Family Cites Families (14)

• 1984
  • 1984-06-08 FR FR8409056A patent/FR2565731A1/fr not_active Withdrawn
• 1985
  • 1985-06-05 DE DE8585902573T patent/DE3564744D1/de not_active Expired
  • 1985-06-05 JP JP60502478A patent/JPS61502645A/ja active Pending
  • 1985-06-05 US US06/841,866 patent/US4697055A/en not_active Expired - Fee Related
  • 1985-06-05 WO PCT/FR1985/000141 patent/WO1986000169A1/fr active IP Right Grant
  • 1985-06-05 EP EP85902573A patent/EP0183755B1/de not_active Expired
  • 1985-06-07 CA CA000483464A patent/CA1239432A/fr not_active Expired

Non-Patent Citations (1)

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