Gas-insulated high or medium voltage circuit breaker

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

a first arcing contact and a second arcing contact, wherein at least one of the two arcing contacts is axially movable along a switching axis, wherein during a breaking operation, an arc between the first arcing contact and the second arcing contact is formed in an arcing region;

a nozzle including a channel directed to the arcing region, for blowing an arc-extinguishing gas to the arcing region during the breaking operation;

a diffuser portion adjacent to the nozzle, for transporting the arc-extinguishing gas from the arcing region to a region downstream of the diffuser portion;

a buffer volume directly downstream of the diffuser portion;

an enclosure confined within a housing of the circuit breaker, wherein the enclosure substantially surrounds the buffer volume circumferentially; and

a buffer dividing member connected to the diffuser portion as to divide the buffer volume into a first and a second buffer sub-volume, wherein the buffer dividing member has one or more apertures allowing a flow of gas between the first and the second buffer sub-volume through the buffer dividing member,

wherein the buffer dividing member is substantially disc-shaped and substantially extending radially.

2. The gas-insulated high or medium voltage circuit breaker according to claim 1 , wherein the second arcing contact passes slideably through a center portion of the buffer dividing member.

3. The gas-insulated high or medium voltage circuit breaker according to claim 1 , wherein a cross-sectional area of the one or more apertures provided on the buffer dividing member is in a range of 20% to 45% of a total cross-sectional surface of the buffer dividing member.

4. The gas-insulated high or medium voltage circuit breaker according to claim 1 , wherein a total cross-sectional surface of the buffer dividing member is in a range of 80 cm 2 to 160 cm 2 .

5. The gas-insulated high or medium voltage circuit breaker according to claim 1 , wherein at least a part of the enclosure is formed as a portion of a nominal current path, and the buffer dividing member is slideable along an inner surface of the enclosure.

6. The gas-insulated high or medium voltage circuit breaker according to claim 1 , wherein the buffer dividing member substantially extends from one end of the buffer volume to another end of the buffer volume.

7. The gas-insulated high or medium voltage circuit breaker according to claim 1 , wherein the buffer dividing member is a coaxially arranged shell extending along an axial length of the buffer volume.

8. The gas-insulated high or medium voltage circuit breaker according to claim 1 , wherein 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.

9. The gas-insulated high or medium voltage circuit breaker according to claim 1 , wherein the buffer dividing member is connected to a ring-like portion of the diffuser portion.

10. The gas-insulated high or medium voltage circuit breaker according to claim 1 , wherein during the breaking operation, the arc-extinguishing gas flows from the arcing region via the first sub-volume of the buffer volume to the second sub-volume, wherein from the second sub-volume, the arc-extinguishing gas is released to an exhaust at a side of the buffer volume axially further remote from the arcing region.

11. The gas-insulated high or medium voltage circuit breaker according to claim 1 , further comprising a gear system operatively coupled to the nozzle and the second arcing contact for providing a relative movement between the nozzle and the second arcing contact along the switching axis.

12. The gas-insulated high or medium voltage circuit breaker according to claim 1 , wherein the gas-insulated high or medium voltage circuit breaker is a self-blast circuit breaker.

13. The gas-insulated high or medium voltage circuit breaker according to claim 1 , wherein the buffer dividing member is formed as a sheet.

14. A method of operating the gas-insulated high or medium voltage circuit breaker, the method comprising:

breaking an electric current by the gas-insulated high or medium voltage circuit breaker according to claim 1 .

15. The gas-insulated high or medium voltage circuit breaker according to claim 1 , wherein the gas-insulated high or medium voltage circuit breaker comprises a puffer-type circuit breaker.