7th International Conference on Electric Power Equipment– Switching Technology (ICEPE 2024)

121 / 2024-04-13 18:31:03

The influence of different nozzle design elements on the pressure and flow velocity during opening process of a gas blast interrupter

gas blast interrupter,gas pressure,gas flow velocity,nozzle,no-load opening

Due to the reliable breaking capability of fault current with short and medium arc duration, gas blast circuit breaker is widely used in actual power grid. In the process of current breaking, the compression chamber should be established a high enough gas pressure rapidly, so that there could be gas flow with extremely high speed between the two sides of the breaks, taking away the heat inside the arc column and lowing the arc temperature, resulting in extinguish of the arc. The nozzle is one of the important components of a circuit breaker, which is used to form high-speed gas flow between the breaks. Its design parameters can affect both the pressure establishment effect of the compression chamber and the gas flow velocity in the nozzle throat during the interruption process, and then affect the breaking performance of the interrupter. Based on fluid simulation software, this paper studies the influence of different design parameters of a typical nozzle for gas blast circuit breaker on the pressure of compression chamber and the gas flow velocity of the nozzle throat during no-load opening operation. The simulation result shows that the diameter and length of nozzle throat affect both the pressure building in the compression chamber and the airflow velocity of the nozzle throat. The transition arc between the nozzle downstream and the nozzle throat mainly affects the pressure building in the compression chamber, while the release angle of the nozzle downstream affects the airflow velocity of the nozzle throat. The size of the gas passage in the nozzle upstream has limited influence on the pressure in the compression chamber and the airflow velocity in the nozzle throat.