GAS-INSULATED HIGH OR MEDIUM VOLTAGE CIRCUIT BREAKER

Abstract

 The invention relates to a gas-insulated high or medium voltage circuit breaker (1) comprising:
a first arcing contact (2) and a second arcing contact (3), whereby the first arcing contact (2) and/or the second arcing contact (3) is axially movable along a switching axis (4), thereby forming, during a breaking operation, an arc (5) between the first arcing contact (2) and the second arcing contact (3) in an arcing region (6),
a first nominal contact (7) circumferentially surrounding the first arcing contact (2) and a second nominal contact (8) circumferentially surrounding the second arcing contact (3),
a first side shield (9) and a first side cylinder (10) circumferentially surrounding the first nominal contact (7) and a second side shield (11) and a second side cylinder (12) circumferentially surrounding the second nominal contact (8),
a chamber insulating tube (13) connecting the first side shield (9) and the second side shield (11) circumferentially around the arcing region (6), and
at least one one-way valve (14) configured for allowing, during the breaking operation, an arc-extinguishing gas to escape from the arcing region (6) and/or to enter the chamber insulating tube (13).

Description

Technical Field

[0001] The invention relates to a gas-insulated high or medium voltage circuit breaker comprising a first arcing contact and a second arcing contact, whereby the first arcing contact and/or the second arcing contact is axially movable along a switching axis, thereby forming, during a breaking operation, an arc between the first arcing contact and the second arcing contact in an arcing region, a first nominal contact circumferentially surrounding the first arcing contact and a second nominal contact circumferentially surrounding the second arcing contact, a first side shield and a first side cylinder circumferentially surrounding the first nominal contact and a second side shield and a second side cylinder circumferentially surrounding the second nominal contact, and a chamber insulating tube connecting the first side shield and the second side shield circumferentially around the arcing region.

Background Art

[0002] Circuit breakers are well known in the field of medium and high voltage switching applications and are predominantly used for interrupting a current, when an electrical fault occurs. As an example, circuit breakers have the task of opening contacts and keeping them apart from one another in order to avoid a current flow even in case of high electrical potential originating from the electrical fault itself. The circuit breaker may break medium to high short circuit currents of 1 kA to 80 kA at medium to high voltages of 12 kV to 72 kV and up to 1200 kV. The operation principle of circuit breakers is known. Such circuit breakers are arranged in the respective electrical circuits which are intended to be interrupted based on some predefined event occurring in the electrical circuit.

[0003] Generally, operation of such circuit breakers are responsive to detection of a fault condition or fault current. On detection of such a fault condition or fault current, a mechanism may operate the circuit breaker so as to interrupt the current flowing there through, thereby interrupting the current flowing in the electrical circuit. Once a fault is detected, contacts within the circuit breaker separate in order to interrupt the electrical circuit. Often spring arrangements, pneumatic arrangements or some other means utilizing mechanically stored energy are employed to separate the contacts. Some of the energy required for separating the contacts may be obtained from the fault current itself. When interrupting the current flowing in the electrical circuit, an arc is generally generated. This arc must be cooled so that it becomes quenched or extinguished, such that the gap between the contacts repeatedly can withstand the voltage in the electrical circuit. It is known to use, air, oil or insulating gas as medium in which the arc forms. Insulating gas comprises for example Sulphur hexafluoride (SF6) or CO2.

[0004] In metal-enclosed breakers, hot insulating gas from the arc-zone escapes towards an exhaust volume provided at an end portion of the circuit breaker. The insulating gas is then cooled by mixing with cold insulating gas and released into a tank of the circuit breaker. However, most of SF6 alternatives such as for example Airplus C5K mixtures, C4FN, CO2-O2 mixtures etc., may not recombine after decomposition during arc interruption. Such behaviour may have a direct impact on system operating conditions leading to an increase in pressure in the tank. The pressure in the metal enclosure i.e. in the tank may become higher than in the arcing region. In such cases, a back flow can occur from the tank to the arcing region. Such back flow will be responsible of carrying generated particles and dust in the arcing region, which negatively affects operational stability of the circuit breaker. Thus, such back flow should be avoided as it may introduce risks and uncertainties in interruption performances due to late-restrikes or dielectric breakdowns.

Summary of invention

[0005] It is therefore an object of the invention to provide an improved circuit breaker which avoids back flow into the arcing region.

[0006] The object of the invention is solved by the features of the independent claims. Preferred implementations are detailed in the dependent claims.

[0007] Thus, the object is solved by a gas-insulated high or medium voltage circuit breaker comprising a first arcing contact and a second arcing contact, whereby the first arcing contact and/or the second arcing contact is axially movable along a switching axis, thereby forming, during a breaking operation, an arc between the first arcing contact and the second arcing contact in an arcing region, a first nominal contact circumferentially surrounding the first arcing contact and a second nominal contact circumferentially surrounding the second arcing contact, a first side shield and a first side cylinder preferably overlappingly arranged and circumferentially surrounding the first nominal contact and a second side shield and a second side cylinder preferably overlappingly arranged and circumferentially surrounding the second nominal contact, a chamber insulating tube connecting the first side shield and the second side shield circumferentially around the arcing region, and at least one one-way valve configured for allowing, during the breaking operation, an arc-extinguishing gas to escape from the arcing region and/or to enter the chamber insulating tube.

[0008] A key point of the invention is to use an one-way valve allowing only a flow from the arcing region towards an exhaust and not vice versa respectively allowing natural convection into the chamber insulating tube. Thus, due to the one-way valve back flow can be restricted resulting in less particles in the arcing region respectively resulting in no late restrikes and dielectric failures of the circuit breakers. The one-way valve preferably comprising no moving parts, thus resulting in no maintenance and malfunctioning compared with a traditional variant. The one-way valve can be positioned at end of and/or within an exhaust tube at a moving contact side and/or in an exhaust volume formed by the first side shield and first side cylinder, close to a flow path entry to a tank formed by the first side shield and first side cylinder and/or second side shield and second side cylinder, and/or within insulating tube holes for flow due to natural convection. In the later variant the one-way valve can carry cold gas from a bottom of the tank into the chamber insulating tube, whereby flow may be only in one direction from bottom to top and not vice versa through the chamber, for avoid getting particles along with the flow into the chamber insulating tube and for avoiding flashovers. Besides that the one-way valve may be placed downstream of a diffuser or in exhaust parts blocking the flow and for a better mixing of hot and cold gases.

[0009] The term high or medium voltage relates to voltages that exceeds 1 kV. A medium voltage preferably concerns nominal voltages in the range from 12 kV to 72 kV (medium voltage range), like 25 kV, 40 kV or 60 kV. A high voltage preferably relates to nominal voltages in the range from above 72 kV to 550 kV, like 145 kV, 245 kV or 420 kV. Nominal currents of the circuit breaker can be preferably in the range from 1 kA to 5 kA. The current which flows during the abnormal conditions in which the circuit breaker performs its duty may be appropriately referred to as referred to as the breaking current or the short circuit current. The short circuit current may be in the range from 31.5 kA to 80 kA, which is termed high short-circuit current duty. During a breaking operation, breaking voltages may be very high, e.g., in the range from 110 kVto 1200 kV.

[0010] In a gas-insulated circuit breaker, the arc-extinguishing medium comprises a gas. First side shield, first side cylinder, second side shield, second side/cylinder and/or chamber insulating tube form an encapsulating housing which defines a volume for the gas. According to some embodiments, the circuit breaker can include a gas blowing system configured to extinguish an arc formed between the first arcing contact and the second arcing contact of the circuit breaker during a stage of the current interruption operation. Preferably, the first arcing contact, the first side cylinder and/or first side shield are movably, whereas the second arcing contact, the second side cylinder and/or second side shield are fixed.

[0011] The arc-extinguishing gas can be any suitable gas that enables to adequately extinguish the electric arc formed between the arcing contacts during a current interruption operation, such as, but not limited, to an inert gas as, for example, sulphur hexafluoride SF6. Thereby, the arc between the first and second arcing contacts develops in the arcing region. Specifically, the arc-extinguishing gas used in the circuit breaker can be SF6 gas or any other dielectric insulation medium, may it be gaseous and/or liquid, and in particular can be a dielectric insulation gas or arc quenching gas. Such dielectric insulation medium can for example encompass media comprising an organofluorine compound, such organofluorine compound being selected from the group consisting of: a fluoroether, an oxirane, a fluoroamine, a fluoroketone, a fluoroolefin, a fluoronitrile, and mixtures and/or decomposition products thereof. Herein, the terms "fluoroether", "oxirane", "fluoroamine", "fluoroketone", "fluoroolefin" and "fluoronitrile" refer to at least partially fluorinated compounds. In particular, the term "fluoroether" encompasses both hydrofluoroethers and perfluoroethers, the term "oxirane" encompasses both hydrofluorooxiranes and perfluorooxiranes, the term "fluoroamine" encompasses both hydrofluoroamines and perfluoroamines, the term "fluoroketone" encompasses both hydrofluoroketones and perfluoroketones, the term "fluoroolefin" encompasses both hydrofluoroolefins and perfluoroolefins, and the term "fluoronitrile" encompasses both hydrofluoronitriles and perfluoronitriles. It can thereby be preferred that the fluoroether, the oxirane, the fluoroamine and the fluoroketone are fully fluorinated, i.e. perfluorinated.

[0012] The dielectric insulation medium can be selected from the group consisting of: a hydrofluoroether, a perfluoroketone, a hydrofluoroolefin, a perfluoronitrile, and mixtures thereof. In particular, the term "fluoroketone" as used in the context of the present invention shall be interpreted broadly and shall encompass both fluoromonoketones and fluorodiketones or generally fluoropolyketones. Explicitly, more than a single carbonyl group flanked by carbon atoms may be present in the molecule. The term shall also encompass both saturated compounds and unsaturated compounds including double and/or triple bonds between carbon atoms. The at least partially fluorinated alkyl chain of the fluoroketones can be linear or branched and can optionally form a ring. The dielectric insulation medium may comprise at least one compound being a fluoromonoketone and/or comprising also heteroatoms incorporated into the carbon backbone of the molecules, such as at least one of: a nitrogen atom, oxygen atom and sulphur atom, replacing one or more carbon atoms. More preferably, the fluoromonoketone, in particular perfluoroketone, can have from 3 to 15 or from 4 to 12 carbon atoms and particularly from 5 to 9 carbon atoms. Most preferably, it may comprise exactly 5 carbon atoms and/or exactly 6 carbon atoms and/or exactly 7 carbon atoms and/or exactly 8 carbon atoms.

[0013] Further, the dielectric insulation medium may comprise at least one compound being a fluoroolefin selected from the group consisting of: hydrofluoroolefins (HFO) comprising at least three carbon atoms, hydrofluoroolefins (HFO) comprising exactly three carbon atoms, trans-1,3,3,3-tetrafluoro-1-propene (HFO-1234ze), 2,3,3,3-tetrafluoro-1-propene (HFO-1234yf), and mixtures thereof. The organofluorine compound can also be a fluoronitrile, in particular a perfluoronitrile. In particular, the organofluorine compound can be a fluoronitrile, specifically a perfluoronitrile, containing two carbon atoms, and/or three carbon atoms, and/or four carbon atoms. More particularly, the fluoronitrile can be a perfluoroalkylnitrile, specifically perfluoroacetonitrile, perfluoropropionitrile (C2F5CN) and/or perfluoro-butyronitrile (C3F7CN). Most particularly, the fluoronitrile can be perfluoroisobutyronitrile (according to the formula (CF3)2CFCN) and/or perfluoro-2-methoxypropanenitrile (according to formula CF3CF(OCF3)CN). Of these, perfluoroisobutyronitrile (i.e. 2,3,3,3-tetrafluoro-2-trifluoromethyl propanenitrile alias i-C3F7CN) is particularly preferred due to its low toxicity. The dielectric insulation medium can further comprise a background gas or carrier gas different from the organofluorine compound (in particular different from the fluoroether, the oxirane, the fluoroamine, the fluoroketone and the fluoroolefin) and can in embodiments be selected from the group consisting of: air, N2, O2, CO2, a noble gas, H2; NO2, NO, N2O; fluorocarbons and in particular perfluorocarbons, such as CF4; CF31, SF6; and mixtures thereof. For example, the dielectric insulating gas can be CO2 in an embodiment.

[0014] The circuit breaker may include one or more components such as, a puffer-type cylinder, a self-blast chamber, a pressure collecting space, a compression space, or puffer volume, and an expansion space. The circuit breaker may effectuate interruption of the electrical circuit by means of one or more of such components, thereby discontinuing flow of electrical current in the electrical circuit, and/or extinction of the arc produced when the electrical circuit is interrupted. The circuit breaker can include also other parts such as a drive, a controller, and the like, which have been omitted in the description. These parts are provided in analogy to a conventional high or medium voltage gas-insulated circuit breaker. The term "axial" designates an extension, distance etc. in the direction of the axis. An axial separation between parts means that these parts are separated from each other when seen or measured in the direction of the axis. The term "radial" designates an extension, distance etc. in a direction perpendicular to the axis. The term "cross-section" means a plane perpendicular to the axis, and the term "cross-sectional area" means an area in such a plane. The axis can be, for example, the switching axis.

[0015] Generally, various possibilities exist for implementation of the one one-way valve. According to a preferred implementation the at least one one-way valve is provided as tesla-valve, preferably comprising a plurality of turns, more preferably connected in parallel and/or in series. A tesla valve advantageously comprises no moving parts such that no maintenance is required. A tesla valve has a design that allows fluid to flow unimpeded in one direction, but in the other direction, the fluid is blocked. Thereby, an interior of the valve is preferably provided with enlargements, recesses, projections, baffles, or buckets which, while offering virtually no resistance to the passage of the fluid in one direction, other than surface friction, constitute an almost impassable barrier to its flow in the opposite. Preferably two, three, four or more one-way valves are connected in parallel and/or in series.

[0016] In another preferred implementation the at least one one-way valve, the first side shield and the first side cylinder are 3D printed as one piece or the at least one one-way valve, the second side shield, and the second side cylinder are 3D printed as one piece. Advantage of a 3D printed one-way valve, the first side shield, the first side cylinder, the second side shield, the second side cylinder and/or chamber insulating tube is that the valve does not have moving parts and thus being maintenance free. The 3D printed one-way valve, the first side shield, the first side cylinder, the second side shield, the second side cylinder and/or chamber insulating tube is preferably of a material composition, for example, including PTFE (polytetrafluoroethylene), FEP (fluorinated ethylene propylene), PFA (perfluoroalkoxy alkane), TFM (modified PTFE), MOS2 (molybdenum disulfide), BN (boron nitride), combinations thereof, or any fillings of one of these materials with another one. For example, in one combination, one of these materials can be used as a matrix and another one can be used as a filler. Preferably, the first side shield, the first side cylinder with at least one one way valve; the second side shield, the second side cylinder with at least one one-way valve and/or the chamber insulating tube with at least one way valve are 3D printed together in a single manufacturing step. Preferably, the at least one one-way valve and/or the chamber insulating tube are 3D printed as one piece, and/or the at least one one-way valve and the first side shield, the first side cylinder, the second side shield, the second side cylinder and/or the chamber insulating tube are 3D printed as one piece.

[0017] In a further preferred implementation, the at least one one-way valve is arranged between the first side shield and the first side cylinder, between the second side shield and the second side cylinder, and/or passed through the first arcing contact, and is configured for allowing the arc-extinguishing gas to escape from the arcing region. The one-way valve preferably extends in axial direction. The first side shield and/or the second side shield are preferably arranged in an overlapping manner with the first side cylinder and/or the second side cylinder, whereby the one one-way is arranged in the overlapping area. The first side shield and/or the second side shield preferably circumferentially encapsulate together with the first side cylinder and/or the second side cylinder and the chamber insulating tube in a closed manner, except the one one-way valve, the first arcing contact and/or the second arcing contact and the first nominal contact and/or the second nominal contact. First nominal contact and/or the second nominal contact are preferably arranged circumferentially around the first arcing contact and/or the second arcing contact.

[0018] In another preferred implementation the at least one one-way valve is passed through the chamber insulating tube, the first side shield and/or the second side shield, and is configured for allowing the arc-extinguishing gas to enter the chamber insulating tube. The one-way valve preferably extends in radial direction. The chamber insulating tube is preferably provided in a tube-like manner, whereby the tube circumferentially overlaps with the first side shield and/or the second side shield.

[0019] According to a further preferred implementation the gas-insulated high or medium voltage circuit breaker comprises at least two one-way valves arranged at opposite and preferably diagonally opposite sides of the chamber insulating tube, whereby one part of the one-way valves is configured for allowing the arc-extinguishing gas to escape from the chamber insulating tube and another part of the one-way valves is configured for allowing the arc-extinguishing gas to enter the chamber insulating tube. Preferably at least two one-way valves are arranged at each side and/or extend in radial direction. In another preferred implementation a plurality of one-way valves are passed at least through the chamber insulating tube, and in particular are arranged side-by-side. Preferably the complete axial extension of the chamber insulating tube constitutes of one-way valves arranged side-by-side. The one-way valves are preferably arranged at radially opposite sides of the chamber insulating tube.

[0020] In another preferred implementation the first arcing contact comprises as prolongation an exhaust tube for the arc-extinguishing gas to escape and the at least one one-way valve is provided within the exhaust tube. In such case the one-way valve preferably extends in axial direction.

[0021] According to a further preferred implementation the gas-insulated high or medium voltage circuit breaker comprises a plurality of one-way valves connected in series in an axially extending manner within chamber insulating tube. Preferably the one-way valves extend over a complete axial extension of the chamber insulating tube.

[0022] In another preferred implementation the gas-insulated high or medium voltage circuit breaker comprises a buffer cylinder including a channel directed to the arcing region and/or a nozzle for blowing during the breaking operation the arc-extinguishing gas to the arcing region. In this respect to the buffer cylinder may be axially fixed to the nozzle such that the channel can be circumferentially encased at least partially by both the buffer cylinder and the nozzle.

[0023] In another preferred implementation the circuit breaker is a gas-insulated circuit breaker adapted to interrupt medium to high-voltages of 12 kV or more, 52 kV or more, or more than 72 kV, or 145 kV or more; and/or wherein the gas-insulated high or medium voltage circuit breaker is one of a puffer-type circuit breaker, a selfblast circuit breaker, or a combination thereof.

[0024] The object is further solved by a method of operating a gas-insulated high or medium voltage circuit breaker, the method comprising:
Breaking an electric current with the high or medium voltage circuit breaker as described before.

[0025] According to a preferred implementation, breaking the electric current comprises:
Separating the first arcing contact and the second arcing contact by moving the first arcing contact and/or the second arcing contact along the switching axis to initiate a breaking operation.
For breaking the electric current, the arcing contacts can be separated by moving the first arcing contact along the switching axis to initiate a breaking operation. By at least partially releasing the arc-extinguishing gas from the buffer volume the temperature of the arc-extinguishing gas in the buffer volume can be decreased. Accordingly, also the probability or risk of a restrike or late restrike, i.e. a reignition of the arc, due to a flow reversal of heated gas from the buffer volume back to the arcing zone can be decreased.

[0026] The object is further solved by a method for manufacturing a gas-insulated high or medium voltage circuit breaker, the circuit breaker comprising:

a first arcing contact and a second arcing contact, whereby the moving contact is axially movable along a switching axis, thereby forming, during a breaking operation, an arc between the first arcing contact and the second arcing contact in an arcing region,

a first nominal contact circumferentially surrounding the first arcing contact and a second nominal contact circumferentially surrounding the second arcing contact,

a first side shield and a first side cylinder preferably overlappingly arranged and circumferentially surrounding the first nominal contact and a second side shield and a second side cylinder preferably overlappingly arranged and circumferentially surrounding the second nominal contact, and

a chamber insulating tube connecting the first side shield and the second side shield circumferentially around the arcing region, and the method comprising the circuit breaker and the step of:
installing the at least one one-way valve, between the first side shield (9) and the first side cylinder, between the second side shield and the second side cylinder and/or in the chamber insulating tube for allowing, during the breaking operation, an arc-extinguishing gas to escape from the arcing region and/or to enter chamber insulating tube.

[0027] According to a preferred implementation, the method comprises the steps of

3D printing the at least one one-way valve; and

Installing the at least one 3D printed one-way valve between the first side shield and the first side cylinder, between the second side shield and the second side cylinder, and/or passed through the first arcing contact for allowing the arc-extinguishing gas to escape from the arcing region, and/or

Installing the at least one 3D printed one-way valve passed through the chamber insulating tube, the first side shield and/or the second side shield for allowing the arc-extinguishing gas to enter the chamber insulating tube.

[0028] In a further preferred implementation, the method comprises the step of

3D printing the first side shield, the first side cylinder and the at least one one-way valve as one piece with the least one one-way valve installed between the first side shield and the first side cylinder;

3D printing the second side shield, the second side cylinder and the at least one one-way valve as one piece with the least one one-way valve installed between the first side shield (9) and the first side cylinder; and/or

3D printing the chamber insulating tube and the at least one one-way valve as one piece with the least one one-way valve passed through the chamber insulating tube.

[0029] Installing preferably comprises firmly and/or fixed installing the 3D printed one-way valve, for example by means of gluing and/or mechanical adjustment, for example comprising drilling and mechanically fixing.

[0030] Further implementations and advantages of the method are directly and unambiguously derived by the person skilled in the art from the circuit breaker as described before.

Brief description of drawings

[0031] These and other aspects of the invention will be apparent from and elucidated with reference to the implementations described hereinafter.

[0032] In the drawings:

Fig. 1 shows a gas-insulated circuit breaker according to a preferred implementation in a schematic view,

Fig. 2a shows a chamber insulating tube of the circuit breaker of Fig. 1 according to a preferred implementation in a schematic cross-sectional view,

Fig. 2b shows a chamber insulating tube of the circuit breaker of Fig. 1 according to a further preferred implementation in a schematic cross-sectional view,

Fig. 3a shows a chamber insulating tube of the circuit breaker of Fig. 1 according to a further preferred implementation in a schematic cross-sectional view,

Fig. 3b shows a second side shield and a second side cylinder of the circuit breaker of Fig. 1 according to the preferred implementation in a schematic cross-sectional view, and

Fig. 4 shows a chamber insulating tube of the circuit breaker of Fig. 1 according to a further preferred implementation in a schematic cross-sectional view.

Description of implementations

[0033] Although the following description is given with respect to a gas-insulted circuit breaker 1, and particularly with respect to a gas-insulated high or medium voltage circuit breaker 1 for medium and high voltage applications, it is to be understood that the implementations of the present disclosure are not limited thereto. Instead, the present implementations could be applied anywhere where a gas-insulated circuit breaker 1 is needed. For simplicity, implementations described herein often refer to a circuit breaker 1, instead of referring to a gas-insulated high or medium circuit breaker 1. The circuit breaker 1 may be a puffer type circuit breaker, a self-blast circuit breaker, a generator circuit breaker, a disconnector, a combined disconnector and circuit breaker, a live tank breaker, or a load break switch in power transmission and distribution systems. The circuit breaker 1 can comprise also other parts such as nominal contacts, a drive, a controller, and the like, which have been omitted in the Figures and are not described herein in detail. These parts are provided in analogy to a conventional high or medium voltage gas-insulated circuit breaker.

[0034] Fig. 1 shows a gas-insulated circuit breaker 1 according to a preferred implementation described herein, for high or medium voltages. The circuit breaker 1 includes a first arcing contact 2 and a second arcing contact 3. The first arcing contact 2 is in Fig. 1 exemplarily in the form of a tulip, e.g. a contact tulip, whereby the second arcing contact 3 is in the form of a rod, e.g. a contact rod. The two arcing contacts 2, 3 co-operate with each other between an open end-position, in which the two arcing contacts 2, 3 are completely electrically separated from each other, as shown in Fig. 1, and a closed end-position, in which an electric current can pass between them. The moving acing contact 2 is part of a moving breaking contact having a first nominal contact 7. Further, the second arcing contact 3 is part of a fixed breaking contact with a second nominal contact 8.

[0035] The arcing contacts 2, 3 are constituted in a manner such that they can conveniently carry an interruption current, so that the arcing contacts 2, 3 do not generate excessive heating and withstand the heat of an arc 5 generated during a current interruption operation of the circuit breaker 1. In particular, arcing contacts 2, 3 are made of any suitable material, typically arc-resistant material, that enables the circuit breaker 1 to function as described herein, such as exemplarily, but not limited to: copper, copper alloys, silver alloys, tungsten, tungsten alloys, or any combination(s) thereof. In particular, these materials are chosen on the basis of their electrical conductivity, hardness (i.e. resistance to abrasive wear), mechanical strength, low cost, and/or chemical properties. For example, the contact rod shown in Fig. 1 and forming the second arcing contact 3 is made of any suitable conductive material which enables the circuit breaker 1 to function as described herein, such as exemplarily, but not limited to, copper. If required, the contact rod may be made of different materials, for example, different parts thereof may be made of different materials or be coated with a material which provides adequate electrical and/or mechanical properties to each of these parts.

[0036] As indicated by arrows in Fig. 1, the first arcing contact 2 e.g. as part of the moving breaking contact, is movable relatively to the second arcing contact 3 along a switching axis 4 to bring the arcing contacts 2, 3 in the open end-position or in the closed end-position. In the closed end-position, the second arcing contact 3 is inserted into the first arcing contact 2. During the breaking operation, the first arcing contact 2 moves away from the second arcing contact 3 so that both contacts separate from one another. During the breaking operation, as shown in Fig. 1, arc 5 develops in the arcing region 6 between portions of the first and second arcing contact 2, 3.

[0037] The circuit breaker 1 shown in Fig. 1 is arranged in a gas-tight housing filled with an electrically insulating gas or arc-extinguishing gas. The volume between the housing and the components of the circuit breaker 1 shown in Fig. 1 is inside the gastight housing. The gas-tight housing can be constituted as an encapsulation, such as, but not limited to, a metallic or ceramic housing. The encapsulation comprises a first side shield 9 and a first side cylinder 10overlappingly arranged and circumferentially surrounding the first nominal contact 7, and a second side shield 11 and a second side cylinder 12 overlappingly arranged and circumferentially surrounding the second nominal contact 8. A chamber insulating tube 13 circumferentially connects the first side shield 9 and the second side shield 11 around the arcing region 6 in an overlapping manner.

[0038] The circuit breaker 1 further includes least one one-way valve 14 for allowing, during the breaking operation, an arc-extinguishing gas to escape from the arcing region 6 and/or to enter the chamber insulating tube 13. The implementation in Fig. 1 comprises a total of nine one-way valves 14 at different positions, described in the following with reference to Figs. 2 to 4 in more detail. Generally, the depicted one-way valves 14 are provided as tesla-valves, having in Fig. 2a a plurality of turns, or connected in parallel in Fig. 3a or in series in Fig. 4a. Thereby the one-way valves 14 are 3D printed of a material composition, for example, including PTFE (polytetrafluoroethylene), FEP (fluorinated ethylene propylene), PFA (perfluoroalkoxy alkane), TFM (modified PTFE), MOS2 (molybdenum disulfide), BN (boron nitride), combinations thereof, or any fillings of one of these materials with another one. in one combination, one of these materials can be used as a matrix and another one can be used as a filler.

[0039] In Figs. 2a, 2b, 3a and 4a one-way valves 14 are passed through the chamber insulating tube 13, whereas in Fig. 1 the one-way valves 14 are also passed through the first side shield 9, left side, and the second side shield 10, right side. The one-way valves 14 are thereby configured for allowing the arc-extinguishing gas to enter the chamber insulating tube 13. In Fig. 2a one-way valves 14 are arranged at axially and radially opposite sides at the chamber insulating tube 13, whereas in Fig. 2b one-way valves 14 are arranged at diagonally opposite sides of the chamber insulating tube 13. Thereby on one radial side the one-way valves 14 are configured for allowing the arc-extinguishing gas to escape from the chamber insulating tube 13 and on an opposite radial site the one-way valves 14 are configured for allowing the arc-extinguishing gas to enter the chamber insulating tube 13.

[0040] More specifically, in Fig. 2a the one-way valves 14 are arranged at four distant locations each close to margins of the chamber insulating tube 13, whereas each one-way valve 14 comprises multiple turns. Escape one-way valves 14 and enter one-way valves 14 are arranged 180° distant to each other so that gas can travel in a radial manner through the chamber insulating tube 13. In Fig. 2b the one-way valves 14 comprise only one turn. As the one-way valves 14 are arranged at diagonally opposite sides close to margins of the chamber insulating tube 13, gas can travel in a diagonal manner through the chamber insulating tube 13, entering through the bottom one-way valves 14 and leaving through the top one-way valves 14.

[0041] The one-way valves 14 can be firmly attached and/or integrated with the chamber insulating tube 13, of the chamber insulating tube 13 can be 3D printed along with the one-way valves 14. The one-way valves 14 can be placed in selected locations and in a number that is suitable to provide efficient thermal convection for the gas and to provide sufficient volume that is required to be replaced within the chamber insulating tube 13 for efficient operation of the circuit breaker 1.

[0042] Fig. 3a shows an implementation where the plurality of one-way valves 14 are passed through the chamber insulating tube 13, arranged side-by-side along the complete radial extension of the chamber insulating tube 13. One part is of the one-way valves 14 is arranged at one radial side and the other part of the one-way valves 14 is arranged at the opposite radial side of the insulating tube 13 so that the one-way valves 14 allow a gas flow in radial direction.

[0043] Generally, Fig. 3a shows an example case with one-way valves 14 placed all along the length of the chamber insulating tube 13, while the one-way valves 14 can be limited, for example, only in specific regions only in the left side with limited length and right side with limited length, with no one-way valves 14 placed in the centre to ensure that hot gas does not cause any gas electrical breakdown near the centre of the chamber insulating tube 13. The one-way valves 14 may also be placed only in the top region, around 90° region, for example around the arc surface of -15° to +15° region, of the circular transverse cross section of the chamber insulating tube 13 and in the bottom region as 270° region, for example around the arc surface of -15° to +15° region, in particular with no one-way valves 14 at the side region i.e. at around 180° and 360°. Thereby an arc surface length for the one-way valve 14 may be up to 30° on top and bottom of the chamber insulating tube 13.

[0044] While the one-way valves 14 are shown with one turn and are placed to vertically release gas, the number of turn and the gas path inside the one-way valves 14 can be designed to concentrate gas release in the region that is most suitable, for example less interfering with electrical activities and thermally efficient. For example, the gas path inside the no one-way valves 14 can be angled to take in air from the centre of the chamber insulating tube 13 but release the gas either at the left side of the chamber insulating tube 13 or at the right side of the chamber insulating tube 13 using an inclined and/or angled path design for the turns designed in some of the one-way valves 14 integrated in the chamber insulating tube 13.

[0045] Fig. 4a shows another implementation with a plurality of one-way valves 14 connected in series one behind each other in an axially extending manner within chamber insulating tube 13, thereby allowing a gas flow in axial direction. Such way the one-way valves 14 may form part of a wall or the wall of the within chamber insulating tube 13 such that gas can flow from one margin of the within chamber insulating tube 13 to the opposite margin of the within chamber insulating tube 13. While Fig. 4a shows only one wall equipped with one-way valves 14, further walls with one-way valves 14 may be present e.g. opposite at 180°, or further at 90° and 270°.

[0046] Again referring to Fig. 1, said figure shows four one-way valves 14, each two of them arranged at opposite radial sites in annular gaps between the first side shield 9 and the first side cylinder 10 and between the second side shield 11 and the second side cylinder 12, thereby allowing the arc-extinguishing gas to escape in axial direction. Fig. 3b shows such an implementation in more detail, whereby one-way valves 14 are shown at opposite sides, while further one-way valves 14 can be incorporated or integrated all along the annular gaps between the first side shield 9 and the first side cylinder 10 and between the second side shield 11 and the second side cylinder 12 or at incorporated or integrated at specific locations, at 90° and 270°, for example. Fig. 4b shows an implementation where the first arcing contact 2 comprises as prolongation an exhaust tube 15 for the arc-extinguishing gas to escape from the arcing region 6. The one-way valve 14 is provided within the exhaust tube 15, thereby allowing the arc-extinguishing gas to escape in axial direction.

[0047] Again referring to Fig. 1, the circuit breaker 1 further includes a nozzle 17 having a channel directed to the arcing region 6 respectively the arc 5. The nozzle 17 serves as a blowhole for blowing the arc-extinguishing gas to the arcing region 6 during the breaking operation. Thereby, the arc 5 can be extinguished or quenched. The nozzle 17 includes an insulating nozzle 9. The arc-extinguishing gas for blowing out the arc 5 is provided in a volume upstream of an insulating nozzle. For example, the volume upstream of the insulating nozzle can be filled with a dielectric gas, such as in embodiments CO2, SF6 or SF6 and its known mixtures, such as N2 or CF4. In further embodiments, also other insulating or arc-extinguishing gases are possible.

[0048] The insulating nozzle is arranged adjacent to the channel, in the axial direction to the nozzle 17. A cross-sectional area of the insulating nozzle may increase in the axial direction away from the nozzle 17. The insulating nozzle may form a diverging duct for the flow of the arc-extinguishing gas. Accordingly, the arc-extinguishing gas from the volume upstream of the insulating nozzle is transported from the arcing region 6 to a region downstream of the insulating nozzle. The region downstream of the insulating nozzle includes a buffer volume provided directly downstream of the insulating nozzle. Accordingly, after the arc-extinguishing gas passes through the arcing region 6 and the insulating nozzle, the arc-extinguishing gas reaches the buffer volume. The buffer volume is substantially surrounded by a second enclosure 11 circumferentially. That is to say, the second enclosure 11 can substantially delimit the radial extent of the buffer volume 10. The term "buffer volume directly downstream of the insulating nozzle" as used herein can be understood as in direct fluid communication with the arcing region 6.

[0049] The circuit breaker 1 can include a gear system operatively coupled to at least one of the arcing contacts 2, 3 and the nozzle 17 for providing a translation along the switching axis. At least a portion of the gear system can be arranged at a supporting structure. The circuit breaker 1 can be provided as a single motion circuit breaker. That is to say, only one of the arcing contacts 2, 3 is movable along the switching axis 4. Alternatively, the circuit breaker can be a double motion circuit breaker. In other words, both of the first and the second arcing contacts 2, 3 are movable along the switching axis 4.

[0050] Further, an arc-extinguishing system for extinguishing the arc 5 can be integrated in the volume upstream of the nozzle 17. The arc-extinguishing system can have a pressurizing system (puffer system). The pressurizing system can for example include a pressurizing chamber (puffer chamber) having a quenching gas contained therein. The quenching gas can be a portion of the insulation gas contained in the housing volume (outer volume) of the circuit breaker 1. The pressurizing chamber can be delimited by a chamber wall and a piston for compressing the quenching gas within the pressurizing chamber during the current breaking operation.

[0051] To this purpose, the piston moves jointly with the first arcing contact 2 so that the piston pressurizes the quenching gas within the pressurizing chamber when the first arcing contact 2 is moved away from the second arcing contact 3 for opening the circuit breaker 1. The nozzle 17 can be adapted for blowing the pressurized quenching gas, e.g. the arc-extinguishing gas, from the volume upstream onto the arc 6 formed during the current breaking operation. The nozzle 17 can include an inlet connected to the pressurizing chamber for receiving the pressurized quenching gas from the pressurizing chamber, and the nozzle 17 outlet to the arcing region 6. The nozzle 17 is preferably made of an electrically insulating material, as for example, PTFE. The nozzle 17 can comprise a ring portion attached at one of its ends.

[0052] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed implementations. Other variations to be disclosed implementations can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting scope.

Reference signs list

[0053] 

1

circuit breaker

2

first arcing contact

3

second arcing contact

4

switching axis

5

arc

6

arcing region

7

first nominal contact

8

second nominal contact

9

first side shield

10

second side shield

11

first side cylinder

12

second side cylinder

13

chamber insulating tube

14

one-way valve

15

exhaust tube

16

buffer cylinder

17

nozzle

Claims

1. A gas-insulated high or medium voltage circuit breaker (1) comprising:

a first arcing contact (2) and a second arcing contact (3), whereby the first arcing contact (2) and/or the second arcing contact (3) is axially movable along a switching axis (4), thereby forming, during a breaking operation, an arc (5) between the first arcing contact (2) and the second arcing contact (3) in an arcing region (6),

a first nominal contact (7) circumferentially surrounding the first arcing contact (2) and a second nominal contact (8) circumferentially surrounding the second arcing contact (3),

a first side shield (9) and a first side cylinder (10) circumferentially surrounding the first nominal contact (7) and a second side shield (11) and a second side cylinder (12) circumferentially surrounding the second nominal contact (8),

a chamber insulating tube (13) connecting the first side shield (9) and the second side shield (11) circumferentially around the arcing region (6), and

at least one one-way valve (14) configured for allowing, during the breaking operation, an arc-extinguishing gas to escape from the arcing region (6) and/or to enter the chamber insulating tube (13).

2. The gas-insulated high or medium voltage circuit breaker (1) according to the previous claim, whereby the at least one one-way valve (14) is provided as tesla-valve, preferably comprising a plurality of turns, more preferably connected in parallel and/or in series.

3. The gas-insulated high or medium voltage circuit breaker (1) according to any of the previous claims, whereby the at least one one-way valve (14), the first side shield (9) and the first side cylinder (10) are 3D printed as one piece or the at least one one-way valve (14), the second side shield (11) and the second side cylinder (12) are 3D printed as one piece.

4. The gas-insulated high or medium voltage circuit breaker (1) according to any of the previous claims, whereby the at least one one-way valve (14) and the chamber insulating tube (13) are 3D printed as one piece.

5. The gas-insulated high or medium voltage circuit breaker (1) according to any of the previous claims 1, 2 or 4, whereby the at least one one-way valve (14) and the first side shield (9), the first side cylinder (10), the second side shield (11), the second side cylinder (12) and/or the chamber insulating tube (13) are 3D printed as one piece.

6. The gas-insulated high or medium voltage circuit breaker (1) according to the previous claim, whereby the at least one one-way valve (14) is arranged between the first side shield (9) and the first side cylinder (10), between the second side shield (11) and the second side cylinder (12), and/or passed through the first arcing contact (2), and is configured for allowing the arc-extinguishing gas to escape from the arcing region (6).

7. The gas-insulated high or medium voltage circuit breaker (1) according to any of the previous claims, whereby the at least one one-way valve (14) is passed through the chamber insulating tube (13), the first side shield (9) and/or the second side shield (10), and is configured for allowing the arc-extinguishing gas to enter the chamber insulating tube (13).

8. The gas-insulated high or medium voltage circuit breaker (1) according to the previous claim, comprising at least two one-way valves (14) arranged at opposite and preferably diagonally opposite sides of the chamber insulating tube (13), whereby one part of the one-way valves (14) is configured for allowing the gas to escape from the chamber insulating tube (13) and another part of the one-way valves (14) is configured for allowing the gas to enter the chamber insulating tube (13).

9. The gas-insulated high or medium voltage circuit breaker (1) according to any of the two previous claims, whereby a plurality of one-way valves (14) are passed at least through the chamber insulating tube (13), and in particular are arranged side-by-side.

10. The gas-insulated high or medium voltage circuit breaker (1) according to any of the two previous claims, whereby the first arcing contact (2) comprises as prolongation an exhaust tube (15) for the arc-extinguishing gas to escape and wherein the at least one one-way valve (14) is provided within the exhaust tube (15).

11. The gas-insulated high or medium voltage circuit breaker (1) according to any of the previous claims, comprising a plurality of one-way valves (14) connected in series in an axially extending manner within chamber insulating tube (13).

12. The gas-insulated high or medium voltage circuit breaker (1) according to any of the two previous claims, comprising a buffer cylinder (16) including a channel directed to the arcing region (6) and/or a nozzle (17) for blowing during the breaking operation the arc-extinguishing gas to the arcing region (6).

13. Method for manufacturing a gas-insulated high or medium voltage circuit breaker (1), the circuit breaker (1) comprising:

a first arcing contact (2) and a second arcing contact (3), whereby the first arcing contact (2) and/or the second arcing contact (3) is axially movable along a switching axis (4), thereby forming, during a breaking operation, an arc (5) between the first arcing contact (2) and the second arcing contact (3) in an arcing region (6),

a first nominal contact (7) circumferentially surrounding the first arcing contact (2) and a second nominal contact (8) circumferentially surrounding the second arcing contact (3),

a first side shield (9) and a first side cylinder (10) circumferentially surrounding the first nominal contact (7) and a second side shield (11) and a second side cylinder (12) circumferentially surrounding the second nominal contact (8), and

a chamber insulating tube (13) connecting the first side shield (9) and the second side shield (11) circumferentially around the arcing region (6), and the method comprising the circuit breaker (1) and step of:
installing the at least one one-way valve (14) between the first side shield (9) and the first side cylinder (10), between the second side shield (11) and the second side cylinder (12) and/or in the chamber insulating tube (13) for allowing, during the breaking operation, an arc-extinguishing gas to escape from the arcing region (6) and/or to enter chamber insulating tube (13).

14. Method according to the previous claim, comprising the step of

3D printing the at least one one-way valve (14); and

Installing the at least one 3D printed one-way valve (14) between the first side shield (9) and the first side cylinder (10), between the second side shield (11) and the second side cylinder (12), and/or passed through the first arcing contact (2) for allowing the arc-extinguishing gas to escape from the arcing region (6); and/or

Installing the at least one 3D printed one-way valve (14) passed through the chamber insulating tube (13), the first side shield (9) and/or the second side shield (10) for allowing the arc-extinguishing gas to enter the chamber insulating tube (13).

15. Method according to the previous claims, comprising the step of

3D printing the first side shield (9), the first side cylinder (10) and the at least one one-way valve (14) as one piece with the least one one-way valve (14) installed between the first side shield (9) and the first side cylinder (10);

3D printing the second side shield (11), the second side cylinder (12) and the at least one one-way valve (14) as one piece with the least one one-way valve (14) installed between the first side shield (9) and the first side cylinder (10); and/or

3D printing the chamber insulating tube (13) and the at least one one-way valve (14) as one piece with the least one one-way valve (14) passed through the chamber insulating tube (13).

Drawing