Gas-insulated high-voltage switching device with improved main nozzle

A gas-insulated high-voltage switching device, comprising:

• an arcing contact arrangement comprising a first arcing zone member and a second arcing zone member, wherein the first arcing zone member and the second arcing zone member are movable relative to one another along an axis (B),
• wherein the first arcing zone member comprises a first arcing contact unit;
• and
• wherein the second arcing zone member comprises:
• a second arcing contact unit configured to receive the first arcing contact unit;
• an auxiliary nozzle surrounding at least a part of the second arcing contact unit and having an auxiliary nozzle throat which has an axial extension and allows passage at least of an end of the first arcing contact unit;
• a main nozzle surrounding at least a part of the auxiliary nozzle, and having a main nozzle throat, which has an axial extension sideways of the auxiliary nozzle throat and allows passage at least of the end of the first arcing contact unit,
• a cross-sectional area of the main nozzle throat is substantially decreasing in the axial direction away from the auxiliary nozzle throat so as to form a converging flow duct for a flow of an arc-extinguishing gas, wherein
• the converging flow duct of the main nozzle throat has a length L in the axial direction in a range of 15 mm to 80 mm, and
• the main nozzle throat has an aperture angle a in a range from more than 0° to at most 15° and a shape of the main nozzle throat is frusto-conical.

A method of operating a gas-insulated high-voltage switching device, the method comprising:

• providing a gas-insulated high-voltage switching device, comprising:
• an arcing contact arrangement comprising a first arcing zone member and a second arcing zone member, wherein the first arcing zone member and the second arcing zone member are movable relative to one another along an axis (B),
• wherein the first arcing zone member comprises a first arcing contact unit;
• and
• wherein the second arcing zone member comprises:
• a second arcing contact unit configured to receive the first arcing contact unit;
• an auxiliary nozzle surrounding at least a part of the second arcing contact unit and having an auxiliary nozzle throat which has an axial extension and allows passage at least of an end of the first arcing contact unit;
• a main nozzle surrounding at least a part of the auxiliary nozzle, and having a main nozzle throat, which has an axial extension sideways of the auxiliary nozzle throat and allows passage at least of the end of the first arcing contact unit,
• a cross-sectional area of the main nozzle throat is substantially decreasing in the axial direction away from the auxiliary nozzle throat so as to form a converging flow duct for a flow of an arc-extinguishing gas, wherein
• the converging flow duct of the main nozzle throat has a length L in the axial direction in a range of 15 mm to 80 mm, and
• the main nozzle throat has an aperture angle a in a range from more than 0° to at most 15° and a shape of the main nozzle throat is frusto-conical;
• performing a low short-circuit current switching operation, wherein the switching current is smaller than 0.3 times the rated short-circuit current, particularly wherein the rated short-circuit current is between 31.5 kA and 80 kA.