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In this paper, the complicated arc phenomena in air dc circuit breakers that are widely used in rail transit and vessels are investigated with both experimental and numerical approaches. Initially, the basic arc motion characteristics in the switch are presented by the recorded waveforms and images in the carefully designed breaking experiments. Phenomena of arc stagnation and back commutation are revealed and the influence of arc chamber width on the arc stagnation is preliminarily discussed according to the experimental results. Then, to make the nature of arc motion clear and to determine the influence details of the arc chamber width on arc motion characteristics, a simplified model based on magnetohydrodynamics theory is built and four cases with the arc chambers of different widths are calculated. The simulated arc behavior is presented by the temperature distribution sequences. In addition, the formation process of back commutation is described in detail by the variation of arc column. The influence mechanism of arc chamber width on arc motion is analyzed according to the differences of pressure propagation and temperature distribution in the arc chamber. Furthermore, the calculated arc displacement curves show that the arc stagnation time could be shortened and the risk of back commutation could be reduced by decreasing the arc chamber width within the reasonable extent.

This paper focuses on the numerical investigation of arc plasma behavior in a certain type molded circuit breaker. A 3-D simulation model based on the magneto-hydrodynamics theory is built and calculated. The basic arc parameters are described by the coupled equations of gas dynamics and electromagnetic field. By adopting a thin layer of nonlinear resistance elements to represent the voltage drop of plasma sheath, the arc splitting process is included. The detailed arc behaviors are presented and preliminarily discussed according to the calculated temperature and arc current distributions. Moreover, experiments are carried out to validate the simulation results. The arc voltage acquired by the numerical and experimental approaches shows good agreement.

Within this paper, the arc characteristics in a typical air DC circuit breaker (DCCB) are studied through experimental approach. A specially designed experimental setup is employed to observe the dynamic process of arc evolution. The phenomena of arc commutation and arc stagnation under fault currents are revealed according to the high-speed photography and arc voltage curves. The influence of arc currents on the detailed arc behaviors is preliminary discussed. It is found that the arc would burn continuously between the contacts when the arc current decreases to a relatively small value. Assisting measures should be employed to help the switch interrupt the small arc current. Finally, a simple magnetic system is designed to increases the magnetic driving force of arc motion. And the interruption characteristics of the switch with the external magnetic field are investigated.

This paper focuses on the numerical investigation of arc plasma behaviour in arc chamber of direct current (DC) circuit breaker. A 3-D simulation model of arc chamber including ferromagnetic splitter plates is built and calculated, which is based on magneto-hydrodynamics theory. Coupled electromagnetic and gas dynamic interactions are considered as usual, and a thin layer of nonlinear electrical resistance elements is used to represent the voltage drop of plasma sheath and the formation of new arc roots. Therefore, the arc-splitting process with ferromagnetic plates can be included. To reduce the time consuming, the arc simulation results of arc commutation process from contact to arc runner is taken as the calculation initial condition in the model. Arc motion is described in detail by the temperature distribution. Moreover, the simulation result is compared with experimental result, which shows good agreement.

This paper is devoted to the modeling of air arc plasma in a simplified low-voltage arc chamber considering the turbulence effect. The numerical model is built based on the magnetohydrodynamics, and the turbulent flow field is described by the standard k-e model. The calculated arc behavior is presented by the temperature distribution sequence and shows good agreement with the experimental results. Compared with the simulation results under laminar assumption, the simulated arc characteristics taking turbulence effect into consideration are closer to the real situation.

A 3-D simulation model of air arc plasma in a low-voltage circuit breaker, considering the production of iron vapor from splitter-plate erosion, is developed. The distributions of temperature and mass fraction of iron vapor are calculated. The simulation results indicate that the arc splitting process is strongly influenced by the presence of iron vapor from the splitter plate. Images of arc simulation results are presented.

Arc behavior is very important to the performance of a low-voltage circuit breaker. A 3-D arc model for a certain type of miniature circuit breaker is built and calculated in this paper. The arc evolution is described in detail according to the temperature distribution images from the simulation results.