Study of the effects of gas flow on the performance of gas-blast circuit breakers

Experiments were carried out at a Siemens laboratory with specially designed circuit breakers to investigate the relationship between gas flow and arc behavior for various shapes and arrangements of gas nozzles, as well as for different types of gas and pressure conditions. The current, post-arc current, and voltage measurements were supplemented by the employment of optical methods. By using a high-speed schlieren camera, it was possible to obtain valuable information on the flow characteristics and density of the gas surrounding the arc and to estimate the influence of these quantities on the arc-quenching capacity of a breaker. The interaction of the electric power system and the arc could also be taken into account by using a dynamic arc model.