High-voltage circuit-breaker having optimized contacts design

Abstract

To provide a circuit breaker (1) for a HV circuit-breaker.SOLUTION: The circuit breaker includes a pair of permanent contacts (24, 41), at least one of them being movable along an axis (AA'); an insulating nozzle (30) having a central cylindrical wall (33) defining a longitudinal cylindrical hole (36), along the axis; and a pair of arcing contacts (22, 42), at least one of them being movable along the axis, a lateral wall of one of the arcing contacts being at a distance from the central cylindrical wall thereby defining a cylindrical volume between the arcing contact and the central cylindrical wall, the arcing contact further comprising at least one inner central channel (220) extending along the axis and along part of the arcing contact, and at least one lateral conduit (26) between the at least one inner channel and at least one lateral hole (27).SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present invention relates to a circuit breaker for high voltage applications. It applies to a whole range of high voltage circuit breakers filled with SF6 or any other alternative gas to SF6, such as a mixture of CO2, O2 and fluoronitriles, or a mixture of CO2 and fluoronitriles, or a mixture of CO2 and O2, or a mixture of CO2, O2 and fluoroketones, or a mixture of CO2 and fluoroketones, or a mixture of N2 and fluoronitriles. [Background technology]

[0002] Sulfur hexafluoride (SF6), which is estimated to contribute to the greenhouse effect, is being replaced by other gases, for example the so-called "g3" gas, which contains heptafluoroisobutyronitrile mixed with diluent gases including carbon dioxide and oxygen, which is being used instead of SF6, paving the way for a new generation of high-voltage (HV) electrical transmission equipment. This g3 gas has a significantly reduced environmental impact (the gas's global warming potential (GWP) is reduced by more than 99%).

[0003] Traditionally, when designing older generations of SF6 circuit breakers, it was common to use hollow pins with holes running the entire length of the pin contact. An example of this technology is described in French Patent Application Publication No. 2980033. These older puff-type circuit breakers have since been replaced by modern self-blasting technology in which hollow pins are no longer used.

[0004] A new generation of HV circuit breakers is currently being developed that relies on the SF6-free gas mixtures exemplified above. These SF6-free gas mixtures have reduced interrupting performance and require designs to improve arc quenching performance.

[0005] There is a technical problem of improving the interrupting performance of circuit breaker interrupters, particularly those that implement gas mixtures that do not contain SF6.

[0006] There is therefore a problem of finding new constructions of circuit breakers, particularly of the type that implement a gas mixture that does not contain SF6, for example one of the SF6-free gas mixtures mentioned above.

[0007] There is also the problem of finding new ways to open circuit breakers, particularly those of the type that implement a gas mixture that does not contain SF6, such as one of the SF6-free gas mixtures mentioned above. Summary of the Invention

[0008] SUMMARY OF THE INVENTION In order to solve one or more of the above problems, the present inventors have discovered a new construction for a circuit breaker and a new method for opening a circuit breaker.

[0009] The present invention first provides a pair of permanent or main contacts, at least one of which is movable along an axis (AA') called the axis of the circuit breaker; an insulating nozzle comprising a central cylindrical wall defining a longitudinal cylindrical bore or ring along an axis (AA'); a pair of arcing contacts, at least one of which is movable along an axis (AA'), one side wall of the arcing contact being spaced apart from the central cylindrical wall, thereby defining a volume between the arcing contact and the central wall, the arcing contact further comprising at least one inner channel extending along the axis (AA') and along a portion of the arcing contact, and at least one side groove extending from the at least one inner channel to at least one side hole or outlet, thereby communicating the at least one inner channel of the arcing contact with the cylindrical volume; The present invention relates to an HV circuit breaker comprising:

[0010] An arcing contact with at least one inner channel and at least one side groove allows for improved interruption performance.

[0011] When the circuit breaker opens the arcing contacts, an arc is struck and hot gases are generated.

[0012] The hot gas flows either through the at least one inner channel and / or through the other contact, e.g., the tulip contact, and / or through the volume between the arcing contact and the cylindrical wall of the insulating nozzle. The at least one inner channel thus provides an additional cross section for the hot gas to escape.

[0013] When the radial outlet of at least one pin hole is closed by the insulating nozzle, the gas flow is highly restricted. When the radial or lateral outlet is released, at least one inner channel is opened and the gas can pass through it and be discharged through at least one lateral outlet, for example into the exhaust volume.

[0014] At least one internal channel inside the arcing contact allows a portion of the hot gases generated by the arc to flow into the arcing contact.

[0015] At least one inner channel has a limited length, which allows for limiting the pressure drop within the channel, and this limited channel length also allows for opening and closing at least one radial outlet, triggering the opening of the outlet after a predetermined stroke, thereby allowing for the release of the blast at the required location.

[0016] The length of the at least one inner channel is selected to release the side hole only when necessary. If the length is too short, the effectiveness of the circuit breaker according to the present invention is limited. If the length is too long, an unnecessary premature pressure drop may occur inside the at least one channel. In one embodiment, the at least one inner channel extends a distance X along the axis (AA') of 10 mm to 150 mm.

[0017] At least one lateral groove is - along an axis perpendicular to the circuit breaker axis (AA') -or along an axis that forms an angle α of less than 90° with the axis (AA') of the circuit breaker, -or along an axis which forms an angle α of more than 90° with the axis (AA') of the circuit breaker, It can be extended.

[0018] The angle is therefore selected to increase the exhaust and provide maximum flow when at least one radial outlet is open.

[0019] For example, the angle may be between 40 and 60 degrees.

[0020] In the circuit breaker according to the invention, the at least one inner channel may have a diameter of 1 to 8 mm, which is preferably selected to avoid large gas flows through the holes, which can be problematic for some gases, especially when CO2-based gas mixtures (which are more prone to leak than the previous SF6-based gases) are used.

[0021] The equivalent overall cross section of the at least one inner channel can also be achieved by a series of two or more smaller channels having the same overall cross section as the single channel. The shape of the at least one inner channel is preferentially cylindrical, but may also be elliptical, rectangular in cross section, or spiral. Any shape that provides a cross section in a single or multiple channels is included in this application.

[0022] A circuit breaker according to the present invention may be housed in a gas-filled enclosure (metallic or insulating).

[0023] The gas may be, for example, SF, but may alternatively include, for example, heptafluoroisobutyronitrile (CAS number 42532-60-5) and / or heptafluoroisopropyl trifluoromethyl ketone (also known as 2-butanone, 1,1,1,3,4,4,4-heptafluoro-3-(trifluoromethyl)-(CAS number 756-12-7)) and / or CO and / or O and / or N and / or an alternative gas comprising an oxygenated compound, for example, both CO and a fluorinated compound, such as heptafluoroisobutyronitrile and / or heptafluoroisopropyl trifluoromethyl ketone.

[0024] Alternatively, the gas comprises a mixture of CO2, O2 and a fluoronitrile, or a mixture of CO2 and a fluoronitrile, or a mixture of CO2 and O2, or a mixture of CO2, O2 and a fluoroketone, or a mixture of CO2 and a fluoroketone, or a mixture of N2 and a fluoronitrile.

[0025] The present invention also relates to a method for opening a circuit breaker according to the invention as described above or disclosed in the present application, in one embodiment the method comprises: - opening the main contact and then the pair of arcing contacts; - then opening or separating the pair of arcing contacts from one another, thereby inducing an arc between them, and causing the gas to flow along the central channel extending along the (AA') axis and then along the side grooves, thereby escaping into the cylindrical volume and the exhaust volume.

[0026] The present invention provides - providing the advantage of limiting the maximum cross section of the holes and thus limiting the leakage of gases, e.g. CO2 or any CO2-based gas mixtures; -Limiting the length of the channel through which the pin passes -Release pinhole outlet only when necessary - Optimize hole angle exit This improves on the known device. [Brief explanation of the drawings]

[0027] [Figure 1A] 1 illustrates an example of a circuit breaker according to the present invention. [Figure 1B] 1 illustrates an example of a circuit breaker according to the present invention. [Figure 1C] 1 illustrates an example of a circuit breaker according to the present invention. [Figure 2] 10A and 10B show another embodiment of a circuit breaker according to the present invention. [Figure 3] 10A and 10B show another embodiment of a circuit breaker according to the present invention. [Figure 4] 10A and 10B show another embodiment of a circuit breaker according to the present invention. [Figure 5A] FIG. 2 is another view of an embodiment of a circuit breaker according to the present invention in a closed position. [Figure 5B] FIG. 2 is another view of an embodiment of a circuit breaker according to the present invention in an open position. [Figure 6A] 10A and 10B are diagrams showing variations of the pin of the circuit breaker according to the present invention; [Figure 6B] 10A and 10B are diagrams showing variations of the pin of the circuit breaker according to the present invention; [Figure 7A] FIG. 1 shows a comparative example of a known circuit breaker. [Figure 7B] FIG. 10 is a diagram showing a comparative example of a circuit breaker according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] An embodiment of a circuit breaker 1 according to the present invention will be described with reference to Figures 1A to 5B.

[0029] Each of them forms part of an enclosure or tank (not shown), for example of metal or insulating, or part of an isolating chamber, which is filled with a gas, for example SF or other gases, such as heptafluoroisobutyronitrile (CAS number 42532-60-5) and / or heptafluoroisopropyl trifluoromethyl ketone (also called 2-butanone, 1,1,1,3,4,4,4-heptafluoro-3-(trifluoromethyl)-(CAS number 756-12-7)) and / or CO and / or O and / or N and / or gases containing oxygenated compounds, other gases containing both CO and fluorinated compounds, for example heptafluoroisobutyronitrile and / or heptafluoroisopropyl trifluoromethyl ketone. Other possible gases are a mixture of CO2, O2 and fluoronitrile, or a mixture of CO2 and fluoronitrile, or a mixture of CO2 and O2, or a mixture of CO2, O2 and fluoroketone, or a mixture of CO2 and fluoroketone, or a mixture of N2 and fluoronitrile.

[0030] The circuit breaker 1 according to the present invention extends along an axis AA' and comprises a pair of contacts 2, 4 mounted for movement relative to one another along the axis AA' with the aid of an actuation system 102 (see, for example, Figures 5A and 5B). They can be moved from a closed position, in which current can flow, to an open position, in which current is interrupted, and vice versa. Figures 5A and 5B show an embodiment of a circuit breaker according to the present invention implementing dual action, in a closed position (Figure 5A) and an open position (Figure 5B).

[0031] By convention, the term "main contact" is used to refer to the electrical contact through which the rated current passes. The main contact is related to the "arcing contact" which functions to interrupt the arc. The term "moving contact" is used to refer to the main and arcing contact assembly directly connected to the operating system.

[0032] High voltage circuit breakers are a first movable contact 4, for example with a multi-finger (tulip-shaped) arcing contact 42 and a main contact 41; a second contact 2, in this example fixed (but which may alternatively be a moving contact, as shown in Figures 5A and 5B), comprising an arcing contact 22 (in this example a pin) and a main contact 24; Equipped with.

[0033] Reference numeral 50 denotes a pipe placed inside the contact 42, which allows a gas blast to circulate and also to operate the moving contact.

[0034] The arcing contacts are made of a metallic material, for example, copper or a tungsten alloy.

[0035] These two contacts cooperate between a closed position (shown, for example, in FIG. 5A) in which the two contacts 2, 4 pass current between them, and an open position (shown, for example, in FIG. 5B) in which they are separated from each other. Figures 1A-4 show intermediate positions between the fully open and fully closed positions, and Figures 5A and 5B show the fully closed position (FIG. 5A) and the fully open position (FIG. 5B).

[0036] During the breaking procedure, the two main contacts 41, 24 first separate (they are in contact with each other in the closed position), then the arcing contacts 42, 22, after a waiting time caused by the length of their mutual engagement, if any, separate to form an electric arc 19, which is extinguished by compressed insulating gas that is blasted in the zone between the arcing contacts 22, 42, and the arcing contacts 22, 42 then move further apart.

[0037] The insulating nozzle 30 extends between the two contacts 2, 4 and is fixed relative to the contact 4.

[0038] Insulating nozzle 30 includes an internal bore 34 (see FIG. 1B ) having a cylindrical wall 33 defining a cylindrical volume 36 and extending from an inlet 302 (facing or facing toward arcing contact 42) to an outlet 304 (facing or facing toward exhaust volume 28). A portion of arcing contact 22 is contained within volume 36 at a distance from cylindrical wall 33.

[0039] During the interruption procedure, the arcing contact 22 slides inside the cylindrical volume 36 from a closed position (shown in FIG. 5A) where the arcing contact 22 is in contact with the arcing contact 42, to an intermediate position (FIG. 1A) where they are separated but still relatively close to each other, then to a position where they are further apart (FIGS. 1B-4), and finally to a position where the high voltage circuit breaker is fully open (FIG. 5B).

[0040] The arcing contact 22 comprises at least one inner channel 220, which extends over a distance X between a front entrance 222 of the contact (facing the other arcing contact 42) and an end wall 224. Furthermore, a lateral groove 26 extends from the inner channel 220 to the outer surface of the arcing contact, whereby a lateral or radial outlet 27 of this groove 26 opens into the cylindrical volume 36. The diameter of the inner channel 220 is, for example, 1 mm to 8 mm.

[0041] The inner channel 220 may be cylindrical, and preferably circular, but may alternatively have a cross-section (in a plane perpendicular to the axis AA') that may be elliptical or rectangular. In other particular embodiments, the inner channel 220 may have another shape, for example, a helical shape.

[0042] When the circuit breaker opens the arcing contacts, an arc 19 occurs between the arcing contacts, generating hot gases.

[0043] This hot gas flows within the inner channel 220, and / or through the other arcing contact 42, and / or within the small cylindrical volume 36 between the arcing contact pin 22 and the wall 33 of the central cylindrical bore 34 of the insulating nozzle 30, and / or towards the arc volume 45 (see FIG. 1B) between the tulip 42 and the nozzle 30. The inner channel 220 therefore provides an additional cross section for the hot gas to escape.

[0044] When the radial outlet 27 of the pinhole is closed by the insulating nozzle 30 (as shown in FIG. 1A), the gas flow is restricted.

[0045] When the radial or side outlet 27 is released or no longer in front of the inner wall 33 of the hole 34 (as shown in FIG. 1B), the gas is released through or along the inner channel 220 and then through or along the side groove 26 to the exhaust volume 28. Two gas flows are shown in FIGS. 1B and 3: one (40) between the arcing contact and the wall 33 of the hole 34, and one (43) along the inner channel 220 and side groove 26.

[0046] Thus, the inner channel 220 inside the arcing contact 22 allows some of the hot gases generated by the arc 19 to flow into the pin arcing contact, then along the lateral grooves 26 and then into the exhaust volume 28.

[0047] The arcing contact 22 has a plurality of inner channels 2201, 2202, as shown in FIG. 1C. 2、 2203, which may be parallel to one another. As shown in this figure, they may open into a common larger channel 221 from which one or more lateral grooves 26 extend as described above and below.

[0048] As shown in FIGS. 1B and 3, L2 is the distance between the free end of the arcing contact 42 and the outlet 304.

[0049] L is the distance between the free end of the arc contact 42 and the side hole 27, which changes when the device opens and closes. In FIGS. 1A and 2, L < L2, and in FIGS. 1B and 3, L > L2. When the distance L exceeds the distance L2, the side outlet 27 of the pin opens, and starting from this position, the interrupter performance improves. L and L2 can be appropriately selected. For example, L2 can be set to 10 mm to 200 mm.

[0050] X (see FIG. 1A) is the fixed length of the channel 220 along the pin 22. Since L2 > X, the opening of the outlet 27 is delayed. The larger X is, the earlier the outlet 27 opens within the volume portion 28. For example, X is 10 mm to 150 mm.

[0051] It is preferable that L < L2 before the arc is expected to be interrupted and L > L2 when the arc is expected to be interrupted.

[0052] A modification of the above embodiment is shown in FIG. 2, which includes at least two side grooves 261 and 262 extending in two different (opposite) directions from the inner channel 220 or 221, thus increasing the gas flow and further improving the performance of the circuit breaker. In particular, if there is sufficient material for opening the through-hole and for the mechanical function of the pin 22, and the pin 22 does not overheat when a short-circuit current flows through it, more such side grooves can be provided.

[0053] Another modification is shown in FIG. 3, where the side groove 26' is inclined with respect to the axis AA' such that the gas flowing through the internal channel 220 and the side groove 26' follows a path having an obtuse angle α, and the angle α is strictly greater than 90°. In other words, the side groove 26' extends along an axis forming a strictly greater than 90° angle α with respect to the axis (AA') of the circuit breaker.

[0054] Another variation is shown in Figure 4, in which two lateral grooves 26'1 and 26'2 extend from the inner channel 220 and are both inclined relative to the axis AA', so that gas flowing through the inner channel 220 and either of these lateral grooves 26'1 and 26'2 follows a path with an obtuse angle (the components are directed away from the tip of the pin 22), and the complementary angle α is strictly greater than 90°.

[0055] According to a further variant (not shown), one or more lateral grooves 26, 26'1, 26'2 are inclined with respect to the axis AA' (components directed towards the tip of the pin 22) such that gas flowing through the inner channel 220 and any of these lateral grooves 26, 26'1, 26'2 follows a path having an acute angle, the angle α being strictly less than 90°, for example between 1° and 90°. In other words, the lateral groove 26' extends along an axis that forms an angle α with the axis (AA') of the circuit breaker that is strictly less than 90°.

[0056] In both Figures 3 and 4, and in any embodiment in which at least one lateral groove is angled relative to the axis AA', the value of the angle is application dependent and can be estimated by computational fluid dynamics numerical simulations.

[0057] More generally, it is possible to have several lateral grooves extending along an axis that forms an angle of more than, greater than or less than 90° with the axis (AA') of the circuit breaker.

[0058] 6A and 6B show different embodiments within the scope of the present invention. In FIG. 6A, several lateral grooves 26'1, 26' 2、 26'3 is aligned along the axis of the pin 22. - In Figure 6B, several lateral grooves 26''1, 26'' 3、 26''4 is aligned along the axis of pin 22 and has a variable or increasing cross section (measured parallel to axis AA').

[0059] These embodiments and the following variations provide a gradual cross-sectional opening.

[0060] In a further embodiment of the invention (not shown), the lateral grooves of Figure 6A or 6B are inclined with respect to the axis AA' as described above in relation to Figures 3 and 4; and / or the pin 22 is provided with a lateral groove symmetrical to the lateral groove of FIG. 6A or 6B with respect to the axis AA'.

[0061] As seen in Figure 4 (but this applies to the other figures as well), the movable contact 42 is contained within a thermal volume 56 located between the arc volume 45 and the compression volume 58. The wall 54 moves with the movable contact 42 to reduce the volume of the compression chamber or volume 58, thereby venting gas (via one or more valves 57 in the wall 54) into the thermal volume 56 and contributing to extinguishing the arc 19.

[0062] 7A and 7B show the results of the multiphysics arc calculations. They show a comparative example of nozzle 30. FIG. 7A is a pin 22 according to the invention without a central channel, the temperature of the gas at the end of the pin is above 8000K. - Figure 7B shows a pin 22 according to the invention with an inner channel 220 and lateral inclined grooves 26 as shown in Figure 3, the temperature of the gas at the tip of the pin 22 (at the same distance between the two arcing contacts as in Figure 7A) is about 3000K, which is significantly lower than the temperature of the gas in the example of Figure 7A.

[0063] In both figures, reference numeral 42 denotes an arcing contact which cooperates with pin 22.

[0064] The present invention finds application in high voltage circuit breakers, for example operating at rated voltages above 52 kV and interrupting currents of several hundred to several thousand amperes.

[0065] The circuit breaker according to the invention can operate in gases, including, for example, SF6. Alternatively, to reduce the greenhouse effect resulting from the use of SF6, the following gases can be used: - a gas containing heptafluoroisobutyronitrile (CAS number 42532-60-5) and / or heptafluoroisopropyl trifluoromethyl ketone (also known as 2-butanone, 1,1,1,3,4,4,4-heptafluoro-3-(trifluoromethyl)- (CAS number 756-12-7)), optionally mixed with a gas or diluent containing at least CO2 and / or O2 and / or N2 and / or oxygenated compounds. -or in a gas containing at least CO2 and / or O2 and / or N2 and / or oxygenated compounds. -or a gas containing a mixture of CO2, O2 and fluoronitrile, or a mixture of CO2 and fluoronitrile, or a mixture of CO2 and O2, or a mixture of CO2, O2 and fluoroketone, or a mixture of CO2 and fluoroketone, or a mixture of N2 and fluoronitrile.

[0066] The improved performance of the circuit breaker according to the present invention reduces the decomposition of a gas, such as one of the alternative gases mentioned above. [Explanation of symbols]

[0067] 1 Circuit Breaker 2 contacts 4 contacts 19 Electric Arc 22 Arcing contact 24 Main contact 26 Lateral groove 27 Exit 28 Exhaust volume 30 Insulating nozzle 33 Cylindrical wall 34 Internal hole 36 Cylindrical volume section 41 Main contact 42 Arcing Contact 45 Arc volume 56 Thermal volume section 58 Compression volume 102 Actuation System 220 Inner Channel 221 channels 222 Front entrance 224 End Wall 302 Entrance 304 Exit

Claims

1. A circuit breaker (1), comprising: a pair of permanent contacts (24, 41), at least one of which (41) is movable along an axis (AA') called the axis of said circuit breaker (1); an insulating nozzle (30) comprising a central cylindrical wall (33) defining a longitudinal cylindrical bore (36) along said axis (AA'); a pair of arcing contacts (22, 42), at least one of which (42) is movable along said axis (AA'), a side wall of one of said arcing contacts (22) being spaced apart from said central cylindrical wall (33) thereby defining a cylindrical volume (36) between said arcing contact (22) and said central cylindrical wall (33), said arcing contact (22) further comprising at least one inner channel (220, 220) extending along said axis (AA') and along a portion of said arcing contact (22); １ , 220 ２ , 220 ３ , 221) and said at least one inner channel (220, 220 １ , 220 ２ , 220 ３ , 221) and at least one side hole (27), thereby forming said at least one inner channel (220, 220 １ , 220 ２ , 220 ３ , 221) communicates with said cylindrical volume (36) through at least one side groove (26, 26', 26 １ , 26 ２， 26' １ , 26' ２， 26' ３， 26' ４ a pair of arcing contacts (22, 42) each comprising A circuit breaker (1).

2. 2. The circuit breaker (1) according to claim 1, wherein said at least one lateral groove (26) extends along an axis perpendicular to said axis (AA') of said circuit breaker (1).

3. 2. The circuit breaker (1) according to claim 1, wherein said at least one lateral groove (26) extends along an axis that forms an angle equal to, strictly greater than, or strictly less than 90° with said axis (AA') of said circuit breaker (1).

4. - arranged at different positions along said axis (AA'), - or arranged at the same position along said axis (AA') A plurality of lateral grooves (26, 26' １ , 26' ３， 26' ４ , 26'' １ , 26'' ３， 26'' ４ 2. The circuit breaker (1) according to claim 1, comprising:

5. a plurality of lateral grooves (26'') arranged at different positions along said axis (AA') and having a variable or increasing cross section measured parallel to said axis (AA'); １ , 26'' ３， 26'' ４ 5. The circuit breaker (1) according to claim 4, comprising:

6. The at least one inner channel (220, 220 １ , 220 ２ , 220 ３ , 221) extend along said axis (AA') over a distance (X) of between 10 mm and 150 mm.

7. The at least one inner channel (220, 220 １ , 220 ２ , 220 ３ 221) has a diameter of 1 mm to 8 mm.

8. The at least one inner channel (220, 220 １ , 220 ２ , 220 ３ 2. The circuit breaker (1) of claim 1, wherein a wall (224) extends along a portion of the arcing contact (22) from a front end of the arcing contact (22) to a wall (224) within the arcing contact (22).

9. The at least one inner channel (220, 220 １ , 220 ２ , 220 ３ 221) is cylindrical, has a circular or elliptical or rectangular cross section, or is spiral.

10. A plurality of inner channels (220, 220 １ , 220 ２， 220 ３ 2. The circuit breaker (1) according to claim 1, comprising:

11. The plurality of inner channels (220, 220 １ , 220 ２， 220 ３ 11. The circuit breaker (1) according to claim 10, wherein the first and second electrodes (221) open into the common channel (221).

12. 2. The circuit breaker (1) of claim 1, wherein the insulating nozzle (30) extends between an inlet (302) directed toward one of the arcing contacts (42) and an outlet (304) directed toward an exhaust chamber (28).

13. The circuit breaker (1) of any one of claims 1 to 12, further comprising a gas-filled enclosure (100).

14. The gas is SF ６ , or heptafluoroisobutyronitrile (CAS No. 42532-60-5) and / or heptafluoroisopropyl trifluoromethyl ketone (also known as 2-butanone, 1,1,1,3,4,4,4-heptafluoro-3-(trifluoromethyl)-(CAS No. 756-12-7)) and / or CO ２ and / or O ２ and / or N ２ and / or oxygenated compounds, e.g., the gas may be CO ２ and fluorinated compounds, such as heptafluoroisobutyronitrile and / or heptafluoroisopropyl trifluoromethyl ketone, - or the gas is CO ２ , O ２ and a mixture of fluoronitriles, or CO ２ and a mixture of fluoronitriles, or CO ２ and O ２ or a mixture of CO ２ , O ２ and a mixture of fluoroketones, or CO ２ and a mixture of fluoroketones, or N ２ 14. The circuit breaker (1) according to claim 13, comprising a mixture of fluoronitrile and fluoronitrile.

15. A method for opening a circuit breaker (1) according to claim 14, comprising: - opening the main contacts; - then separating said pair of arcing contacts (22, 42) from one another, thereby inducing an arc (19) between them, and allowing gas to flow through said at least one inner channel (220, 220) １ , 220 ２， 220 ３ , 221), then along said at least one lateral groove (26, 26', 26 １ , 26 ２， 26' １ , 26' ２， 26' ３， 26' ４ ) and thereby escapes to said cylindrical volume and then to the exhaust volume (28). A method comprising:

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