High voltage puffer breaker and a circuit breaker unit comprising such a puffer breaker

A breaker unit comprising a vacuum interrupter that is electrically connected in series to a high-voltage puffer breaker comprising:

• a puffer unit with a piston that is movably arranged in a puffer cylinder such that a puffer volume is delimited,
• a first contact member being movably arranged relative to a second contact member of the circuit breaker such that a current path is established in a first position where the first contact member is contacting the second contact member and that said current path is interrupted in an arcing zone once the first contact member is moved to a second position where the first contact member is opened from the second contact member, wherein the first contact member is connected to a drive by a piston stem,
• and a nozzle for circumferentially delimiting the arcing zone of the puffer breaker,
• wherein the puffer volume is fluidly connected to the nozzle by a gas channel,
• wherein the piston and the first contact member are attached to the piston stem,
• and wherein the puffer volume comprises the gas channel as well as a portion of the puffer cylinder, wherein the gas channel and said portion of the puffer cylinder are fluidly connected to one another by a port such that a gas flowing in a first direction from the portion of the puffer cylinder is redirected via the gas channel in a second direction towards the nozzle once the first contact member is moved from the first position towards the second position,
• and wherein the gas channel is provided radially outside of the puffer cylinder between a puffer cylinder wall delimiting the puffer cylinder and a wall structure of the puffer unit.

A combination, comprising:

• a HVDC system and
• a circuit breaker unit comprising a vacuum interrupter that is electrically connected in series to a high-voltage puffer breaker comprising:
• a puffer unit with a piston that is movably arranged in a puffer cylinder such that a puffer volume is delimited,
• a first contact member being movably arranged relative to a second contact member of the circuit breaker such that a current path is established in a first position where the first contact member is contacting the second contact member and that said current path is interrupted in an arcing zone once the first contact member is moved to a second position where the first contact member is opened from the second contact member, wherein the first contact member is connected to a drive by a piston stem,
• and a nozzle for circumferentially delimiting the arcing zone of the puffer breaker,
• wherein the puffer volume is fluidly connected to the nozzle by a gas channel,
• wherein the piston and the first contact member are attached to the piston stem,
• and wherein the puffer volume comprises the gas channel as well as a portion of the puffer cylinder, wherein the gas channel and said portion of the puffer cylinder are fluidly connected to one another by a port such that a gas flowing in a first direction from the portion of the puffer cylinder is redirected via the gas channel in a second direction towards the nozzle once the first contact member is moved from the first position towards the second position,
• and wherein the gas channel is provided radially outside of the puffer cylinder between a puffer cylinder wall delimiting the puffer cylinder and a wall structure of the puffer unit.