Arcing Behaviours in the HV Gas-blast interrupters near the downstream contact with cavity

Abstract:
The interaction intensification between the switching arc and the gas flow is an important factor for increasing of interrupting ability in gas-blast HV extinguishing devices. In the paper, the interaction between HV switching arc and gas stream in the “nozzle exit –downstream arc contact with cavity” region is discussed. The purpose of this investigation is to study the influence of the downstream region on the interrupting ability. For cold monoflow two pressure devices the jet within the cavity of downstream contact can excites violent harmonic motion under appropriate nozzle geometric and gas flow conditions (Hartmann resonance tube). The thermal interrupting ability investigations were carried out for two pressure monoflow extinguish arc-chamber for SF6 and air. Theoretical analysis of the gas jet formation near the downstream contact with the cavity and experimental results interrupting ability increase for arc extinguishing (air-,SF6) devices are presented.