Gas-insulated low- or medium-voltage load break switch

Patent metadata

Field	Value
Publication number	US-10964498-B2
Application number	US-201816207946-A
Country	US
Kind code	B2
Filing date	Dec 3, 2018
Priority date	Jun 3, 2016
Publication date	Mar 30, 2021
Grant date	Mar 30, 2021

Abstract

A gas-insulated low- or medium-voltage load break switch includes: a housing defining a housing volume for holding an insulation gas at an ambient pressure; a first arcing contact and a second arcing contact arranged within the housing volume, the first and second arcing contacts being movable in relation to each other along an axis of the load break switch and defining a quenching region in which an arc is formed during a current breaking operation; a pressurizing system having a pressurizing chamber arranged within the housing volume for pressurizing a quenching gas from an ambient pressure p0 to a quenching pressure pquench during the current breaking operation; and a nozzle system arranged within the housing volume for blowing the pressurized quenching gas in a subsonic flow pattern from the pressurization chamber onto the arc formed in the quenching region during the current breaking operation. The nozzle system includes at least one nozzle arranged for blowing the quenching gas from an off-axis position predominantly radially inwardly onto the quenching region.

First claim

The invention claimed is:

1. A gas-insulated low- or medium-voltage load break switch, comprising:
a housing defining a housing volume for holding an insulation gas at an ambient pressure p 0 ;
a first arcing contact and a second arcing contact arranged within the housing volume, the first and second arcing contacts being movable in relation to each other along an axis of the load break switch and defining a quenching region in which an arc is formed during a current breaking operation;
a pressurizing system having a pressurizing chamber arranged within the housing volume for pressurizing a quenching gas to a quenching pressure p quench during the current breaking operation, wherein the quenching pressure p quench and the ambient pressure p 0 satisfy a relationship p 0 <p quench ; and
a nozzle system arranged within the housing volume for blowing the quenching gas in a subsonic flow pattern from the pressurization chamber onto the arc formed in the quenching region during the current breaking operation, wherein the load break switch is designed for maintaining the subsonic flow pattern during current breaking operations,
the nozzle system comprises at least one nozzle arranged for blowing the quenching gas from an off-axis position predominantly radially inwardly onto the quenching region, and
the insulation gas comprises a background gas in a mixture with an organofluorine compound selected from the group consisting of: fluoroether, oxirane, fluoroamine, fluoroketone, fluoroolefin, fluoronitrile, and mixtures and/or decomposition products thereof.

2. The load break switch according to claim 1 , having a rated voltage of at most 52 kV; and/or the load break switch being rated for switching nominal currents in a range of up to 2000 A.

3. The load break switch according to claim 1 , wherein the load break switch is a knife switch or wherein the load break switch has one axially movable contact.

4. The load break switch according to claim 1 , wherein the nozzle system is designed for maintaining the subsonic flow pattern during the current breaking operation; and/or
wherein the nozzle system is designed for maintaining the subsonic flow pattern during current breaking operations; and/or
wherein the nozzle system is designed for maintaining the subsonic flow pattern inside the load break switch; and/or
wherein the nozzle system is designed for avoiding sonic flow conditions at any instant of the current breaking operation and for every current breaking operation to be performed by the load break switch.

5. The load break switch according to claim 1 , wherein the nozzle system comprises a nozzle channel connecting the pressurizing chamber to the nozzle.

6. The load break switch according to claim 5 , wherein the nozzle channel is arranged radially outside the first or second arcing contact, and/or the nozzle channel is arranged in an off-axis position in the load break switch.

7. The load break switch according to claim 1 , it being designed for breaking load currents in a distribution network, ring main unit (RMU) or secondary distribution gas-insulated switchgear (GIS); and/or the load break switch has a capability to switch load currents, but does not have a short-circuit-current interrupting capability; and wherein the load break switch further comprises nominal contacts.

8. The load break switch according to claim 1 , wherein the nozzle system defines a flow pattern for the quenching gas, the flow pattern including:
a stagnation point at which a flow of quenching gas stops,
an upstream region of predominantly radially inward flow towards the stagnation point, and
a downstream region of accelerating flow in a predominantly axial direction away from the stagnation point.

9. The load break switch according to claim 1 , wherein the pressurizing system is a puffer system and the pressurizing chamber is a puffer chamber with a piston arranged for compressing the quenching gas within the puffer chamber during the current breaking operation.

10. The load break switch according to claim 1 , wherein the at least one nozzle is arranged for blowing the quenching gas from an off-axis position onto the quenching region at an incident angle of between 45° to 120° from an axial direction.

11. The load break switch according to claim 1 , wherein the insulation gas has a global warming potential lower than the global warming potential of SF 6 over an interval of 100 years, and wherein the insulation gas comprises at least one gas component selected from the group consisting of: CO 2 , O 2 , N 2 , H 2 , air, N 2 O, a hydrocarbon.

12. The load break switch according to claim 1 , wherein the background gas is selected from the group consisting of: CO 2 , O 2 , N 2 , H 2 , air, in a mixture with the organofluorine compound.

13. The load break switch according to claim 1 , wherein the pressurizing system is configured for pressurizing the quenching gas during the current breaking operation to a quenching pressure p quench satisfying at least one of the following conditions:
p quench <1.8· p 0   i.

p quench >1.01· p 0   ii.

p quench <p 0 +800 mbar  iii.

p quench >p 0 +10 bar  iv.

14. The load break switch according to claim 1 , having a rated voltage of at least 1 kV; and/or the load break switch being rated for currents of more than 1 A; and/or the ambient pressure p 0 in the load break switch is p 0 <=3 bar.

15. The load break switch according to claim 1 , wherein the nozzle comprises an insulating outer nozzle portion; and/or
wherein the load break switch has one or more of the following dimensions:
the nozzle has a diameter in a range of 5 mm to 15 mm,
the pressurizing chamber has a radial diameter in a range of 40 mm to 80 mm, and a maximum axial length in a range of 40 mm to 200 mm;
the first arcing contact and the second arcing contact have a maximum contact separation of up to 150 mm.

16. The load break switch according to claim 15 , wherein at least one of the first contact and the second contact has a hollow section that has an outlet for allowing the quenching gas having flown into the hollow section to flow out at an exit side of the hollow section into an ambient-pressure region of the housing volume of the load break switch.

17. The load break switch according to claim 1 , wherein at least one of the first contact and the second contact has a respective hollow section arranged such that a portion of the quenching gas having been blown onto the quenching region flows from the quenching region into the hollow section.

18. The load break switch according to claim 1 , wherein the load break switch has a controller, the controller having a network interface for being connected to a data network, such that the load break switch is operatively connected to the network interface for at least one of: sending device status information to the data network and carrying out a command received from the data network, and wherein the data network being at least one of: LAN, WAN or internet (IoT).

19. The load break switch according to claim 1 , wherein the load break switch is not a circuit breaker; and/or the pressurizing system is devoid of a heating chamber for providing a self-blasting effect; and/or the load break switch is designed to be arranged in combination with a circuit breaker.

20. A distribution network, ring main unit, or secondary distribution gas-insulated switchgear having the load break switch according to claim 1 .

21. A method of breaking

Assignees

• Abb Schweiz Ag

Inventors

• Galletti Bernardo
• Attar Elham
• Carstensen Jan
• Saxegaard Magne
• Kristoffersen Martin
• Seeger Martin
• Schwinne Michael
• Ranjan Nitesh
• Stoller Patrick

Classifications

• H01H33/88

  the flow of arc-extinguishing fluid being produced or increased by movement of pistons or other pressure-producing parts · CPC title

• H01H33/703

  having special gas flow directing elements, e.g. grooves, extensions · CPC title

• H01H9/52

  Cooling of switch parts (cooling of contacts H01H1/62) · CPC title

• H01H33/7038

  characterised by a conducting tubular gas flow enhancing nozzle · CPC title

• H01H33/56

  Gas reservoirs · CPC title