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EP-4738416-A1 - CIRCUIT-BREAKER

EP4738416A1EP 4738416 A1EP4738416 A1EP 4738416A1EP-4738416-A1

Abstract

The invention relates to a circuit-breaker (1), comprising a gas compression arrangement (4) configured for compressing a quenching gas to be contained therein and which quenching gas is free of sulphur hexafluoride; a first contact (20) and a second contact (30) movable relative to one another along a switching axis (2); a nozzle (40) providing an inflow channel (IN) connecting the gas compression arrangement (4) to an arc zone (3), the inflow channel (IN) constituting a minimal inflow area to be passed by the quenching gas, the nozzle (40) radially restricting the arc zone (3) between the first contact (20) and the second contact (30); wherein, for the quenching gas to exit the arc zone (3), the circuit-breaker (1) provides at least one outlet (OUT1, OUT2) constituting a minimal outflow area, and the minimal inflow area divided by the minimal outflow area defines an inflow-outflow-ratio being at least 0.5.

Inventors

  • STOLLER, PATRICK
  • IORDANIDIS, ARTHOUROS
  • SEEGER, MARTIN
  • GALLETTI, BERNARDO
  • DHOTRE, Mahesh

Assignees

  • Hitachi Energy Ltd

Dates

Publication Date
20260506
Application Date
20241031

Claims (16)

  1. Gas-insulated circuit-breaker (1), comprising a gas compression arrangement (4) configured for compressing a quenching gas to be contained therein and which quenching gas is free of sulphur hexafluoride; a first contact (20) and a second contact (30) movable relative to one another along a switching axis (2); and a nozzle (40) providing an inflow channel (IN) connecting the gas compression arrangement (4) to an arc zone (3), the inflow channel (IN) constituting a minimal inflow area to be passed by the quenching gas, the nozzle (40) radially restricting the arc zone (3) between the first contact (20) and the second contact (30); wherein, for the quenching gas to exit the arc zone (3), the circuit-breaker (1) provides at least one outlet (OUT1, OUT2) constituting a minimal outflow area, and wherein the minimal inflow area divided by the minimal outflow area defines an inflow-outflow-ratio, the inflow-outflow-ratio being at least 0.5.
  2. Circuit-breaker (1) according to the preceding claim, wherein the inflow-outflow-ratio is at least 0.7, or at least 0.9.
  3. Circuit-breaker (1) according to any one of the preceding claims, wherein the inflow-outflow-ratio is 2.0 or less, 1.8 or less, 1.6 or less, 1.4 or less.
  4. Circuit-breaker (1) according to any one of the preceding claims, wherein the inflow-outflow-ratio is at least 1.0 and up to 1.2.
  5. Circuit-breaker (1) according to any one of the preceding claims, wherein the at least one outlet (OUT1, OUT2) includes a first outlet (OUT1) and a second outlet (OUT2), the first outlet (OUT1) is provided by the nozzle (40) and/or the first contact (20), the first outlet (OUT1) exhibiting a first outflow area (C1, C2, CT) of the minimal outflow area, and the second outlet (OUT2) is arranged axially opposite the first outlet (OUT2), is provided by the nozzle (40) and exhibits a second outflow area (C3) of the minimal outflow area.
  6. Circuit-breaker (1) according to the preceding claim, wherein the first contact (20) comprises a central opening (22) corresponding in shape to the second contact (30) for mating therewith, the central opening (22) constituting a first part (C1) of the first outflow area (C1, C2, CT) or constituting the entire first outflow area (C1, C2, CT).
  7. Circuit-breaker (1) according to the preceding claim, wherein the first contact (20) comprises axial slits for provision of elastic movement of contact arms (24) of the first contact (20) when mating or unmating with the second contact (30), the axial slits constituting a further part (CT) of the first outflow area (C1, C2, CT), the first part (C1) and the further part (CT) together constituting the entire first outflow area (C1, C2, CT).
  8. Circuit-breaker (1) according to any one of the preceding three claims, wherein the nozzle (40) comprises a main nozzle (50) and an auxiliary nozzle (60) of which a main nozzle throat (52) and an auxiliary nozzle throat (62) radially restrict the arc zone (3), the main nozzle throat (52) constituting the second outflow area (C3) and the auxiliary nozzle throat (62) being larger than the first outflow area (C1, C2, CT).
  9. Circuit-breaker (1) according to the preceding claim, wherein the inflow channel (IN) is at least in a section formed by a gap between the main nozzle (50) and the auxiliary nozzle (60), and the inflow channel (IN) opens out into the arc zone (3) perpendicularly or obliquely to the switching axis (2).
  10. Circuit-breaker (1) according to the preceding claim, wherein the minimal inflow area is arranged proximal to the arc zone (3) and/or is arranged in a substantially radially extending section of the inflow channel (IN) and is defined by a gap size (B).
  11. Circuit-breaker (1) according to any of claims 1 to 9, wherein the minimal inflow area is arranged distal to the arc zone (3) and/or is arranged in a substantially axially extending section of the inflow channel (IN) and is defined by a gap size (A).
  12. Circuit-breaker (1) according to any one of the preceding claims, wherein the at least one outlet (OUT1, OUT2), particularly the first outlet (OUT1) and/or the second outlet (OUT2), has a circular cross section defined by a radius (RO) to be measured perpendicularly to the switching axis (2) that ranges from 5 mm to 30 mm.
  13. Circuit-breaker (1) according to the preceding claim, wherein the inflow channel (IN) opens out into the arc zone (3) with rounded edges, the curvature of the rounded edges is defined by a radius (RE),
  14. Circuit-breaker (1) according to the preceding claim, wherein the radius (RE) of the rounded edges divided by the radius (RO) of the first (OUT1) or second (OUT2) outlet defines a radius ratio, the radius ratio being at least 0.1 and up to 2.0.
  15. Circuit-breaker (1) according to any one of the preceding claims, wherein the quenching gas comprises at least 2.5 mol% C4-FN, 7.5 mol% O2, and 65 mol% CO2, and particularly the quenching gas consists of 3.5 mol% C4-FN, 10 mol% O2, and 86.5 mol% CO2.
  16. Circuit-breaker (1) according to any one of the preceding claims, wherein the quenching gas is free of C4-FN and comprises at least 80 mol% CO2 and at least 5 mol% O2, and particularly the quenching gas consists of 90 mol% CO2 and 10 mol% O2.

Description

Technical Field The invention relates to a circuit-breaker with an inflow channel connecting a gas compression arrangement with an arc zone, the inflow channel to be passed by quenching gas, and with at least one outlet for the quenching gas to exit the arc zone. Background Art Electrical systems of various types, e.g. circuit-breakers, remain an area of interest. Some existing systems have various shortcomings, drawbacks, and disadvantages relative to certain applications. For example, in some gas-insulated circuit-breakers, improvements in their construction and/or electrical properties for a better reliability may be made. In addition, costs need to be optimized. Accordingly, there remains a need for further contributions in this area of technology. In the operation of a circuit-breaker arcing occurs. The high temperatures of an arc result in heating of the gas, such as quenching gas or insulating gas, in the circuit-breaker, which then can be guided away from the contacts and from an arc zone. There is a continuous demand to optimize the flow of quenching gas through the circuit-breaker, especially in light of compatibility with different types of quenching gas. Particularly, it is a problem to provide continuous enhancement with regard to lifetime and wear, particularly of parts in direct contact with the quenching gas. Summary of invention It is therefore an object of the invention to provide solutions with respect to circuit-breakers that provide an enhanced maintenance, reduced cost, and increased lifetime. Particularly it is an object to avoid or reduce disadvantages of known solutions. The invention is defined by the features of the independent claims. Preferred implementations are detailed in the dependent claims, the description, and the figures. The object is particularly solved by a gas-insulated circuit-breaker comprising a gas compression arrangement, e.g. a gas compression device, configured for compressing a quenching gas to be contained therein, wherein the quenching gas is at least substantially free of sulphur hexafluoride or SF6 and/or does not contain sulphur hexafluoride;a first contact and a second contact movable relative to one another along a switching axis; anda nozzle providing an inflow channel connecting the gas compression arrangement, e.g. indirectly or directly, with/to an arc zone, the inflow channel constituting a minimal inflow area to be passed by the quenching gas, the nozzle radially restricting the arc zone between the first contact and the second contact;wherein, for the quenching gas to exit the arc zone, the circuit-breaker provides at least one outlet constituting a minimal outflow area, andwherein the minimal inflow area divided by the minimal outflow area defines an inflow-outflow-ratio, the inflow-outflow-ratio being at least 0.5. In other words, particularly, an SF6-free breaker is suggested in which an inflow cross section area divided by an outflow cross section area is chosen to exhibit a minimal threshold value, said areas respectively representing narrowest sections for the quenching gas to flow through. Taking into account that the inflow typically comes as compressed gas from a localized path/channel and that the outflow may be directed along one or more paths/channels (e.g. passing both contacts on opposite sides), it is particularly considered that all paths are respected in this ratio. The invention realizes that an enhanced interruption performance can be provided that makes efficient use of quenching gas. Particularly, the circuit-breaker can be used with various sorts of quenching gases, particularly those quenching gases containing less sulphur hexafluoride (SF6) and/or those quenching gases having a lower GWP than SF6. It is also possible that a higher maximum short-circuit current can be realized with quenching gases different from SF gases, e.g. using a quenching gas with CO2 gas. At least substantially free of sulphur hexafluoride particularly means that the volume, mass or molar content of SF6 in the quenching gas is below 1 % or below 0.1 % or below 0.01 % or lower, particularly is zero. The effects and advantages named herein may be improved further by adoption of preferred features or a combination thereof. The features named in the implementations may be individually combined with each other or considered alone. It is noted that same names for features are meant to stand for same features as mentioned in the claims and throughout the description. This is particularly mentioned with respect to some features being referred to with indefinite articles despite having possibly being introduced in a preceding section. Accordingly, with matching feature names in cases with for example two or more indefinite articles of the feature names, the skilled person may adopt the corresponding description in each case. The invention is based on the idea that in the circuit-breaker, typically, a high-energy gas (e.g. with high pressure and/or temperatur