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
  • H01H33/02—Details
  • H01H33/24—Means for preventing discharge to non-current-carrying parts, e.g. using corona ring
• • 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
  • H01H33/72—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid having stationary parts for directing the flow of arc-extinguishing fluid, e.g. arc-extinguishing chamber
  • H01H33/74—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid having stationary parts for directing the flow of arc-extinguishing fluid, e.g. arc-extinguishing chamber wherein the break is in gas

Definitions

• the present invention relates to the field of electrical switchgear for interrupting an electric current, such as circuit breakers, disconnectors, switches and switches, particularly at high or medium voltage.
• the invention relates to a cutting chamber containing an electrically insulating fluid and intended to equip electrical switchgear equipment.
• the insulating fluid also called cutting fluid, is typically a gas such as SF6 sulfur hexafluoride or the like, but the invention can be applied to air, oil, or all other cutoff chambers. other appropriate breaking fluid.
• the interrupting chamber of an electrical switchgear houses two contact members, at least one of which is movable relative to the other in translation in a so-called longitudinal direction, between a closed position in which these organs are in contact with one another so as to allow the passage of an electric current, and an open position in which these organs are separated from one another so as to prohibit the passage of such an electric current.
• These members generally comprise two respective main contacts, sometimes called permanent contacts, and two respective arcing contacts, the first being intended for the passage of electrical current in normal operation while the second are designed to withstand an electric arc during the break. in a well-known way.
• FIG. 1 which illustrates an example of a breaking chamber 10 of a high voltage electric circuit breaker of a known type
• a first contact member 12a comprising a first main contact 14a and a first arcing contact 16a.
• a blowing nozzle 18 secured to said contacts 14a and 16a.
• a second contact member 12b comprising a second main contact 14b and a second arcing contact 16b.
• the first arcing contact 16a takes the form of a tulip while the second arcing contact 16b takes the form of a rod slidable in the first arcing contact 16a.
• the first main contact 14a is designed to slide in the second main contact 14b which takes the form of an annular row of fingers 20 surrounded by a corona shield 22.
• the nozzle 18 is made of an electrically insulating material and extends an insulating gas compression chamber (not visible in FIG. 1) whose volume is reduced during a separation of the arcing contacts 16a and 16b, so that the blast nozzle 18 forms an insulating gas blowing nozzle from the aforesaid compression chamber.
• the circuit-breaker of FIG. 1 is of the double-movement type, that is to say that the two contact members 12a and 12b of the interrupting chamber 10 are movable in opposite directions relative to each other. a fixed frame 24.
• operating means (not shown) of the second contact member 12b act on the first contact member 12a, for example by means of the blowing nozzle 18.
• the document FR 2 953 639 Al describes in more detail an example of a circuit breaker of this type.
• the invention can also be applied to single-action interrupting chambers, that is to say the breaking chambers of which one of the contact members is fixed relative to the chassis.
• the breaking chamber 10 is defined by an outer metal shell (not visible in Figure 1) which allows the confinement of the insulating gas, which consists for example of sulfur hexafluoride SF6.
• the aforementioned operating means operate a mutual distance contact members 12a and 12b, initially in contact with each other.
• the main contacts 14a and 14b are the first to separate, then comes the separation of the arcing contacts 16a and 16b, which gives rise to the formation of an electric arc between them.
• the extinction of this arc is obtained by blowing the insulating gas contained in the interrupting chamber by passing through the arc at the moment of opening of the circuit breaker.
• This blowing is not created by an independent mechanical means, but by a compression established within the aforementioned compression chamber before the circuit breaker opens and, after separation of the contact members, by heating the gas contained in a volume blowing.
• the overpressure that generates the blowing is provided mechanically, by the movement of the movable assembly of the circuit breaker, and / or thermally, by the heat of the electric arc.
• the main contacts 14a, 14b are generally made of copper optionally covered with a silver plating, in order to optimize their electrical conductivity and their cost.
• the arcing contacts 16a, 16b are generally made of tungsten to optimize their resistance to the heating produced by the electric arcs.
• the interrupting chamber 10 may comprise a tube 28 of electrical insulation and centering of the two contact members 12a, 12b relative to each other, called insulating tube in what follows.
• This tube which is made of an electrically insulating material such as epoxy, is mounted at its ends on two internal corona shields 30a and 30b which respectively surround the two contact members 12a and 12b and which are secured respectively to two external corona shields 32a and 32b which are respectively arranged around the contact members 12a and 12b and which are respectively part of two housing parts 24a and 24b which form the housing 24 above and in which are respectively guided the two contact members 12a and 12b.
• the insulating tube 28 is fitted on two respective spans of the two internal corona shields 30a and 30b.
• the aforesaid tube 28 does not participate in the confinement of the insulating fluid and must not be confused with an outer envelope of confinement of the interrupting chamber (not visible in FIG. 1), such an envelope not filling no mutual centering function of the contact members 12a and 12b.
• the first contact member 12a further comprises a bearing surface 34a which is guided in translation by a bore 36a of the inner cap 30a surrounding this contact 12a in the closed position of the contact members, while the second contact member 12b has a bearing surface 34b. which is guided in translation by a bore 36b of the inner cover 30b surrounding this contact 12b in the open position of the contact members.
• each inner corona shield 30a, 30b and external 32a, 32b is made of metal and is electrically connected to the contact member 12a, 12b that surrounds, the function of each corona shield being to constitute a relatively large surface area to the electric potential of the corresponding contact member to reduce the risk of occurrence of an electric arc, in a well known manner.
• channels 38 are formed between each of the inner covers 30a, 30b and the corresponding outer cover 32a, 32b. These channels allow the circulation of the insulating gas.
• low intensity electric arcs can occur between the main contacts 14a and 14b and cause a slight electroerosion of the surface of these contacts, such as to tear particles to said surfaces.
• the friction of the main contacts 14a and 14b on each other during a maneuver of the contact members 12a and 12b is also capable of tearing particles from the respective surfaces of these main contacts.
• the displacement of the contact members 12a and 12b generally induces a depression within the space 42 delimited by the insulating tube 28 in zones 44 located near the longitudinal ends of this tube and therefore near the hoods internal effluents 30a and 30b.
• Each of these zones of depression thus includes, in the vicinity of each other, the insulating tube 28, the insulating gas, and a corona shield 30a, 30b metal, that is to say respective dielectric permittivity media substantially different, so that the electric field in these areas is higher than the average electric field within the space 42 delimited by the insulating tube 28.
• a vacuum of insulating gas in these areas is therefore particularly suitable for a reboot of the breaking chamber 10, which it is desirable to avoid.
• Circuit breakers of this type are however advantageous in terms of size and cost of manufacture.
• the invention aims in particular to provide a simple, economical and effective solution to these problems, avoiding at least partly the aforementioned drawbacks.
• the invention proposes for this purpose a cut-off chamber for electrical switchgear, intended to contain a breaking fluid, and comprising two contact members of which at least one is displaceable in translation in a longitudinal direction of the chamber relative to to a frame thereof, between a closed position in which said members are in mutual contact, and an open position in which said members are mutually separated, said breaking chamber further comprising an electrical insulation tube and centering said members relative to each other which is fixed relative to said frame and which extends longitudinally around said members so as to delimit a space in which they are housed.
• said tube comprises a through orifice formed in a longitudinal wall of the tube and opening radially outwardly of this tube.
• the above-mentioned orifice makes it possible to limit the risks of depression within the space delimited by the tube, and also allows the evacuation, outside this space, of electrically conductive particles resulting from electro-erosion and / or friction. contact organs.
• the invention thus makes it possible generally to reduce the risks of reintroducing the breaking chamber. It should be noted that the electric field in the vicinity of the edges of the orifice is higher than the average electric field within the space delimited by the aforementioned tube, because of a relatively high dielectric permittivity gradient in this zone. . This relatively high electric field favors the attraction of the particles in the orifice of the tube, and therefore the evacuation of these particles.
• Local insulating gas currents within the interrupting chamber can also contribute to the evacuation of the particles.
• This tube is preferably attached to two shields-shields respectively surrounding said contact members, so as to mutually connect these covers.
• the insulating fluid is preferably a gas, such as SF6 sulfur hexafluoride or the like, but may alternatively be air or oil, or any other suitable fluid.
• the breaking chamber according to the invention can advantageously equip a circuit breaker with high or medium voltage, but also a disconnector, a switch, or a switch, when this is of interest.
• said orifice of the tube is shaped so that in the closed position, a transverse plane passing through a contact interface between said contact members of the chamber intercepts said orifice.
• the orifice of the tube is located radially facing a friction zone between the two contact members, where particles can be torn off from the two contact members because of this friction.
• said orifice is shaped so that in the open position, two transverse planes respectively passing through respective contact surfaces of said contact members of the chamber intercept said orifice.
• the orifice is thus sufficiently extended, in the longitudinal direction, so that the respective surfaces of the contact members, whose particles are likely to be torn off in particular by electroerosion, are located radially opposite the orifice during the relative displacement. these bodies from their closed position to their open position. This makes it possible to promote the evacuation, through said orifice, of the particles torn off from the electroerosion contact members.
• Said orifice preferably has a center of symmetry.
• said orifice is generally in the shape of a rectangle with rounded corners whose long sides extend in the longitudinal direction.
• the orifice may be of another form without departing from the scope of the invention, this form preferably being devoid of angles.
• the orifice can thus be of circular, elliptical or other shape.
• said orifice has a edge which is connected to an outer longitudinal surface and to an inner longitudinal surface of said tube respectively by sharp edges.
• Such ridges have the advantage of increasing the intensity of the electric field around the orifice, and thus to promote the attraction of particles to the orifice and their evacuation by the latter.
• each of said contact members comprises at least one arc contact and a main contact surrounding the latter, said contacts being surrounded by said tube.
• the respective main contacts of the contact members allow the passage of electric current in normal operation while the Arc contacts are designed to withstand an electric arc when cutting, in a well known manner.
• the invention also relates to electrical switchgear, such as a high or medium voltage circuit breaker, comprising at least one breaking chamber of the type described above, the orifice of said tube is oriented towards a lower side of the apparatus, as well as at least one particle trap arranged outside the tube.
• electrical switchgear such as a high or medium voltage circuit breaker
• the arrangement of the orifice on the lower side of the apparatus makes it possible to promote the evacuation of the particles under the effect of gravity.
• the gravity is thus added to the force of the electric field and the possible currents of insulating gas to promote the evacuation of the particles through the orifice of the tube.
• said particle trap is arranged opposite said orifice of said tube.
• the invention also relates to a method for trapping electroerosion and / or friction residues of the contact members of an interrupting chamber in an electrical switchgear of the type described hereinafter. above, wherein said residues pass through said orifice of said tube under the effect of gravity and / or an electric field and are then captured by said particle trap.
• FIG. 1 is a partial schematic longitudinal sectional view of a switching chamber of an electrical switchgear of a known type
• FIG. 2 is a partial schematic view in longitudinal section of a breaking chamber of an electrical switchgear according to a preferred embodiment of the invention
• FIG. 3 is a partial schematic in perspective and in longitudinal section of an insulation tube and centering of the contact members of the interrupting chamber of Figure 2.
• FIG. 2 illustrates a breaking chamber of a high-voltage electrical circuit breaker similar to the interrupting chamber shown in FIG. 1 described above, but including the tube 28 of electrical insulation and of centering of the contact members 12a and 12b, also shown alone in Figure 3, has an orifice 46 facing a lower side of the circuit breaker, that is to say down.
• the orifice 46 is generally in the shape of a rectangle with rounded corners whose long sides extend along a longitudinal axis 47 of the chamber.
• This orifice 46 has sharp edges 48 at the junctions of its edge 52 with the inner surface 40 of the tube and with the outer surface 50 thereof. These sharp edges 48 are likely to promote an increase in the electric field near the edges of the orifice 46.
• the longitudinal extent of the orifice 46 is such that a plane P passing through the contact interface between the main contacts 14a and 14b, in the closed position, intercepts the orifice 46, and that passing planes Pa and Pb respectively by the main contacts 14a and 14b, in the open position, also intercept the orifice 46.
• the orifice 46 has a center of symmetry 54 (FIG. 3).
• the particles or residues possibly torn from the contact surfaces 56 (FIG. 2) and respective ones of the main contacts 14a, 14b fall towards the bottom of the interrupting chamber. 10 by gravity, and a majority of these particles converge towards the orifice 46 of the insulating tube 28 under the effect of the electric field present in the vicinity of this orifice, so that these particles fall through the orifice 46.
• a particle trap (not shown in the figures) arranged under the orifice 46 outside the space 42 delimited by the insulating tube 28.
• the dielectric properties of the insulating tube 28 are thus best preserved, and the risk of reinforcement reduced to a minimum.

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• 2011
  • 2011-10-27 FR FR1159744A patent/FR2982069B1/fr active Active
• 2012
  • 2012-10-26 EP EP12779052.5A patent/EP2771897B2/de active Active
  • 2012-10-26 WO PCT/EP2012/071218 patent/WO2013060820A1/fr active Application Filing

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