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
  • H01H33/025—Terminal arrangements
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H1/00—Contacts
  • H01H1/02—Contacts characterised by the material thereof
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H1/00—Contacts
  • H01H1/02—Contacts characterised by the material thereof
  • H01H1/021—Composite material
  • H01H1/023—Composite material having a noble metal as the basic material
  • H01H1/0233—Composite material having a noble metal as the basic material and containing carbides
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H1/00—Contacts
  • H01H1/02—Contacts characterised by the material thereof
  • H01H1/021—Composite material
  • H01H1/023—Composite material having a noble metal as the basic material
  • H01H1/0237—Composite material having a noble metal as the basic material and containing oxides
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H1/00—Contacts
  • H01H1/12—Contacts characterised by the manner in which co-operating contacts engage
  • H01H1/36—Contacts characterised by the manner in which co-operating contacts engage by sliding
  • H01H1/38—Plug-and-socket contacts
  • H01H1/385—Contact arrangements for high voltage gas blast circuit breakers
• • 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
  • H01H33/04—Means for extinguishing or preventing arc between current-carrying parts
  • H01H33/12—Auxiliary contacts on to which the arc is transferred from the main contacts
• • 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
  • H01H33/76—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid wherein arc-extinguishing gas is evolved from stationary parts; Selection of material therefor
  • H01H33/78—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid wherein arc-extinguishing gas is evolved from stationary parts; Selection of material therefor wherein the break is in gas
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H2201/00—Contacts
  • H01H2201/008—Both contacts movable
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H2201/00—Contacts
  • H01H2201/022—Material
  • H01H2201/026—Material non precious

Definitions

• the present invention relates to the field of establishment devices and / or cut-off current with permanent contacts with reduced wear especially for high or medium voltage.
• intermediate voltage and “high voltage” are used in their usual acceptance.
• the term “medium voltage” refers to a voltage that ranges between 1 kV and 52 kV AC and is between 1.5 kV and 75 kV DC.
• the term “high voltage” means a voltage strictly greater than 52 kV AC and strictly greater than 75 kV DC.
• the device for establishing and / or cutting electrical current with permanent contacts can be in particular a circuit breaker, a switch, a disconnector, a contactor.
• a device for establishing and / or cutting electrical current comprises in a breaking chamber filled with a dielectric fluid, such as sulfur hexafluoride, a pair of permanent contacts and a pair of arcing contacts.
• a dielectric fluid such as sulfur hexafluoride
• one of the contacts is fixed and the other is movable so that by moving the movable contacts move the device for establishing and / or cutting electrical current from a closed position to an open position and vice versa.
• the contacts of a pair may both be mobile.
• This switching electric arc is characterized by a very important energy that is sought to minimize to ensure a fast switching and on the other hand to minimize the wear of the main contacts.
• the wear of the contacts leads to a mechanical weakening of the areas of these contacts coming into contact when the device is in the closed position, to a production of metal particles that cause dielectric ignitions between the parts that are live and those that are at potential of the earth and a geometric modification of the shape of the contacts leading to a decrease in the quality of the electrical contact in closed position.
• the arc energy depends on the arc voltage, the arc current and the switching time.
• a disadvantage of the presented configuration is that it is expensive, the coating to be fried before being deposited.
• the movable permanent contact is in the form of a hollow cylinder
• the fixed permanent contact is formed of two concentric hollow cylinders.
• the movable contact In the closed position, the movable contact is inserted between the two concentric cylinders of the fixed permanent contact.
• These two concentric cylinders are offset laterally with respect to each other, the outer cylinder being in the open position closer to the moving permanent contact than is the inner cylinder.
• the outer surface of the moving permanent contact and the inner surface of the outer cylinder are not in mechanical contact, a space is arranged between them.
• the movable contact ends internally with a contact bead and externally is end-coated with an erosion-resistant material located around the bead.
• the bead comes into mechanical and electrical contact with the outer surface of the inner cylinder in the closed position.
• the outer cylinder is internally coated at the end with an erosion resistant coating.
• the object of the present invention is precisely to propose a device for setting up and / or breaking current at high or medium voltage which does not have the drawbacks mentioned above.
• An object of the invention is in particular to provide such a device for establishing and / or cutting power which has a longer life due to reduced wear of its permanent contacts without increasing its size, weight or cost .
• Yet another object of the invention is to reduce the mechanical fragility of permanent contacts. in a setting device and / or power failure without increasing its size, weight or cost.
• a further object of the invention is to preserve for longer than in the prior art the quality of contact in such a device for establishing and / or cutting power.
• Another additional object of the invention is to limit the electrical ignitions in the interrupting chamber of such a device for establishing and / or cutting power.
• Yet another object of the invention is to provide a device for establishing and / or breaking current with permanent contacts which has a reduced switching time, a reduced arc voltage across the main circuit and a decrease in current arc which flows in the main circuit at the time of the establishment of an electric arc.
• the invention more precisely relates to a device for establishing and / or cutting a current comprising a pair of permanent contacts, at least one of the contacts of the pair being mobile.
• At least one permanent contact of the pair comprises a main part having a free end and a terminal protection part integral with the free end of the main part, the end protection part being intended to be in mechanical and electrical contact with the other permanent contact of the pair of permanent contacts that during a maneuver opening or closing the pair of permanent contacts, this part of end protection being made in a single transition metal whose melting temperature is strictly greater than that of the main part with which it is integral, an oxide of such a metal, a carbide of such a metal or the oxide of zinc.
• the transition metal will preferably be selected from tungsten, molybdenum, cobalt, titanium, zirconium, chromium, nickel.
• the terminal protection portion may take the form of a surface coating of the free end of the main portion.
• the coating preferably has a thickness between about 50 and 300 microns.
• the end protection portion may take the form of a tip fixed by screwing or gluing to the free end of the main part.
• this tip is solid.
• the main part is formed of several successive elements assembled together, one of which forms the free end of the main part.
• the permanent contact provided with the terminal protection part may take substantially the form of a hollow cylinder.
• the permanent contact provided with the terminal protection part takes the form of a flange provided with a plurality of fingers.
• the device for establishing and / or breaking the current may further comprise at least one pair of arcing contacts.
• the establishment device and / or power failure can be a circuit breaker, a disconnector, a switch, a contactor.
• FIG. 1A shows in longitudinal section an example of a device for setting and / or breaking of the current object of the invention during an opening operation of the pair of permanent contacts
• FIGS. 1B to 1C show variants of the contacts. permanent of the device
• FIG. 2 illustrates an equivalent electrical diagram of the device for establishing and / or cutting power.
• FIG. 1A there is shown in longitudinal section a current-breaking chamber of an example device for establishing and / or power failure object of the invention. It is assumed that this setting device and / or power failure is a high voltage circuit breaker, it is understood that it could be another type of high or medium voltage device, such as those mentioned above. In the following text, we will use the term circuit breaker without this being limiting.
• the circuit breaker comprises a current breaking chamber 1 delimited by an insulating envelope 2 extending along a longitudinal axis XX ', sealed with a dielectric fluid such as sulfur hexafluoride.
• This insulating envelope 2 houses a pair of permanent contacts 3, 4, one of which is movable along the longitudinal axis XX 'under the action of a rod (not shown) and the other is stationary.
• the moving permanent contact is referenced 3 and the stationary permanent contact is referenced 4.
• the casing further houses a pair of arc contacts 5, 6, one of which is movable along the longitudinal axis XX '.
• the movable arcing contact is referenced 5 and the other arcing contact is referenced 6.
• the permanent and moving arc contacts are integral with each other and therefore move simultaneously during opening or closing operation of the circuit breaker.
• the circuit breaker described is self-compressing and it further comprises an extinguishing nozzle 7 having an orifice closed by the other arcing contact 6.
• the two permanent contacts of the pair could be mobile and not just one of them.
• the two arc contacts of the pair could be mobile and not just one of them.
• the moving arcing contact 5 surrounds the stationary arcing contact 6, while the moving permanent contact 3 is surrounded by the steady stationary contact 4.
• the moving permanent contact 3 takes the form of a cylinder hollow.
• the stationary permanent contact 4 takes the form of a flange provided with fingers which project towards the moving permanent contact 5.
• the circuit breaker is in the process of opening, however the pair of permanent contacts and the pair of arcing contacts are both still closed.
• the path of the nominal current is established between the two permanent contacts 3, 4 of the pair of permanent contacts, they are in mutual mechanical and electrical contact. That's why these two contacts are called permanent.
• the arcing contacts 5, 6 of the pair of arcing contacts are also in mutual mechanical and electrical contact.
• the pair of permanent contacts opens first.
• an electric arc is established between them.
• the current goes through the pair of arc contacts that is still closed.
• the arcing contacts 5, 6 separate an electric arc is established between them.
• the dielectric gas is strongly heated, the pressure increases in the envelope. By a compression effect of the dielectric fluid, a flow of cold gas is blown on the electric arc and its extinction takes place.
• the nominal current passing through the main circuit by the permanent contacts is generally less than 5 kA while the fault current passing in the same circuit is generally of the order of several tens of kilo amperes or even several hundred kilo amps.
• the switching arc is characterized by a very high temperature. For a current of 50 kA, it can reach temperatures above 4700 ° C. Such a temperature favors the wear of the permanent contacts of conventional circuit breakers, a mechanical embrittlement of their ends, a geometric modification of their shape due to erosion and metallic particles are emitted in the breaking chamber. There is an increase in electrical contact resistances and therefore increased heating, a risk of electrical ignition by the presence of metal particles can be deposited on insulating parts.
• FIG. 2 shows a modeling of the electrical circuit diagram of the circuit breaker with a main circuit C1 including the pair of permanent contacts PI and the arcing circuit C2 with the pair of arcing contacts P2, these two circuits C1, C2 being connected in parallel .
• the main circuit C1 is resistive and the arc circuit C2 is a circuit R, L in series.
• the resistance of the main circuit is called RI.
• the inductance of the arc circuit C2 is called L2, its resistance R2.
• the pairs of contacts PI, P2 have been shown closed.
• the resistors R1, R2 include those of the contacts of each pair of contacts PI, P2.
• the inductance L2 in the arc circuit C2 includes that of the dielectric fluid.
• One solution for reducing arc energy is to increase the resistance of at least one of the permanent contacts of the pair to increase the resistance of the main circuit.
• This permanent contact 3 comprises a main part 3.1 having a free end and a terminal protection part 3.2 integral with the free end of the main part. 3.1.
• the terminal protection part 3.2 is made in a single transition metal, this single transition metal having a melting temperature which is strictly greater than that of the main part 3.1 which it protects.
• This terminal protection part 3.2 is in mechanical and electrical contact with the other permanent contact 4 of the pair only during an opening maneuver (before the appearance of an electric arc) or closing the pair permanent contacts. More generally, in case of closure in the presence of the current, the electric arc appears between the non-closed contacts when the distance is sufficient to initiate this arc. The arc goes out when the contacts are "in contact”. In the closed position, it is the main part 3.1 which ensures the mechanical and electrical contact with the other permanent contact 4 of the pair of permanent contacts. In the open position, there is no electrical and mechanical mutual contact.
• this other permanent contact 4 also has a main part 4.1 and a terminal protection part 4.2, the mechanical and electrical contact is between the two main parts 3.1, 4.1 in steady state (closed position) and between the two end protection parts 3.2, 4.2 in the opening or closing operation phase.
• transition metals are considered to be chemical elements of atomic number 21 to 30, 39 to 48, and 72 to 80.
• the transition metals whose melting temperature is higher than that of copper are the following: scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum. Some of these transition metals are rare and therefore expensive.
• Preferred transition metals for the terminal protecting portion are, for example, tungsten, molybdenum, cobalt, titanium, zirconium, chromium, nickel as they are commonly used in electricity and are less expensive. They are perfectly suitable if the main part is made of copper or alloyed copper such as CuCr, CuCrZr, CuZr or even aluminum, these materials being generally superficially silvered. In this case, the material of the terminal protection part will have a higher melting temperature than silver, copper or alloyed copper or aluminum.
• the melting point of these transition metals is given in parentheses: tungsten (3407 ° C), molybdenum (2617 ° C), cobalt (1495 ° C), titanium (1660 ° C), zirconium (1854 ° C), chromium (1857 ° C), nickel (1455 ° C).
• the melting temperature of copper is 1084 ° C, that of silver is 961 ° C and that of aluminum is 660 ° C.
• the transition metals mentioned above to protect copper, its CuCr, CuCrZr, CuZr or aluminum alloys all have higher resistivity than copper and aluminum. By using a terminal protection part in one of these metals, the resistance of the main circuit is well increased. As a variant, it is possible to make the end protection part of an oxide of such a transition metal, of a carbide of such a transition metal or else of zinc oxide whose melting point of the oxide of zinc is 1975 ° C.
• the main part 3.1 can be monoblock or multiblock.
• the terminal protection part 3.2 may take the form of a coating which extends at least over the free end of the main part 3.1 and which extends laterally on the surface of the main part 3.1 so as to face the other permanent contact 4 of the pair, when the pair of permanent contacts is in opening or closing operation phase. There is no mechanical and electrical contact between the coating and the other permanent contact when the pair of permanent contacts is closed, it is only the main parts that are then in mechanical and electrical contact.
• Figure 1B illustrates this configuration of the coating 3.2 and the main part 3.1 monoblock.
• the thickness of the coating may be between about 50 and 300 microns, for example.
• This technique makes it possible to deposit thick coatings on supports of varied nature.
• This technique utilizes a carrier gas for accelerating and transporting liquid, pasty or solid particles from the coating to the support.
• This thermal spraying technique includes flame projection or single flame, supersonic flame projection known as "high velocity oxy fuel” or HVOF, arc wire projection, blown arc plasma projection. , or even the more recent cold spray technique known as "cold spray”.
• the main part 3.1 when multi-block, comprises several main elements 3.10 placed end to end, secured to each other by screwing or gluing, for example.
• One of the main elements is a main end element 3.10.
• the end shield portion may be formed by a coating that covers the end main member as shown in Fig. 1C.
• the coating covers the end of the permanent contact and its surface, this coating being without electrical and mechanical contact with the other permanent contact of the pair in steady state when the circuit breaker is closed.
• FIG. 1A shows a variant in which the end protection part 3.2 is a solid end piece made of the recommended material, this end piece being attached by screwing or gluing at the end of the main part 3.1.
• the terminal protection part 3.2 As far, it has been attempted to describe the terminal protection part 3.2 as belonging to only one of the permanent contacts, the mobile permanent contact.
• This permanent contact takes the form of a cylinder, preferably hollow, to reduce both its mass and energy to set it in motion.
• the terminal protection part 4.2 belongs to the other permanent contact 4, the one surrounding the moving permanent contact 3.
• the other permanent contact 4 may have its main part 4.1 in the form of a collar from which fingers project towards the moving permanent contact 3.
• the free end 4.2 of the fingers acts as a terminal protection part and is made in the recommended material. The end of each of these fingers is intended to come into mechanical and electrical contact with the moving permanent contact when the circuit breaker is in opening or closing operation phase.
• the two permanent contacts of the pair are equipped with the terminal protection part as in FIG. 1A.
• the setting device and / or power failure may not be a circuit breaker, but be a disconnector, a switch, a contactor.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Composite Materials (AREA)
• Materials Engineering (AREA)
• Arc-Extinguishing Devices That Are Switches (AREA)
• Thermally Actuated Switches (AREA)
• Contacts (AREA)
• Fuses (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

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ID=47557253

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Citations (5)

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• 2012
  • 2012-10-19 FR FR1259989A patent/FR2997222B1/fr active Active
• 2013
  • 2013-10-17 EP EP13777286.9A patent/EP2909849B1/fr not_active Revoked
  • 2013-10-17 WO PCT/EP2013/071689 patent/WO2014060498A1/fr not_active Ceased
  • 2013-10-17 IN IN482MUN2015 patent/IN2015MN00482A/en unknown
  • 2013-10-17 CN CN201380054550.5A patent/CN104769693B/zh not_active Expired - Fee Related
  • 2013-10-17 US US14/435,882 patent/US10186389B2/en active Active

Patent Citations (5)

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