One of the main directions of the HV gasblast interrupters modernization is to increase the rated voltage and rated current per one break. The downstream area of the profiled nozzle has a significant effect on the HV gasblast interrupters interruption ability with an increase of the rated voltage. An increase the rated voltage requires an additional drive work to diverge the arcing contacts and an increase in the diameter of the insulating nozzle. Therefore, the HV gasblast interrupters interruption ability decreases due to the pressure gradient degradation, attenuation turbulence effect and others processes in the downstream area. An additional synchronous (controlled) gas injection in the vicinity of current zero from the channel at the nozzle throat area is one of the possible ways to solve the problem providing effective use of arc quenching medium. The channel provides the connection between the compression volume and the nozzle throat area.In this paper, the authors studied the effect of synchronous (controlled) gas injection at different angles of introduction into the nozzle throat region by numerical simulation. The Hartmann principle with the downstream contact with cavity as a resonator is used. SF6 is considered as an arc quenching medium. As a result of the synchronous (controlled) gas injection, the distribution of gasdynamic parameters in the downstream region is varied, additional flow turbulence is provided, the interruption ability is increased
