Simulation of Flow Characteristics in High-Voltage Circuit Breakers

Gas-insulated high voltage circuit breakers are used in the power network to protect the equipment and to isolate the system from the fault. Modelling and simulation are nowadays a key part of the HVCB development process, and understanding the arc quenching process in the nozzle through modelling is important. This paper investigated the first stage of arc quenching process. A comprehensive COMSOL Multiphysics model was developed, in which flow pattern in the nozzle and downstream is investigated without arc condition. Characteristics of supersonic flow including shock position, Mach number distribution and pressure distribution were studied. Results show that the flow behaviour is influenced by gas type, position of downstream electrode and the outlet geometry.