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The effect of copper vapour on fault arc in hybrid DC circuit breaker

A two-dimensional model for fault arc in high-speed switch (HSS) in a hybrid direct current (DC) circuit breaker is developed based on magnetic-hydrodynamic theory to investigate the effect of metal vapour eroded from copper electrodes on fault arc. Different energy transfer mechanisms caused by electrode erosion, including electrode melting, vaporization and chemical reaction are considered. The plasma temperature and pressure rise are simulated. It is found that the effects of increased radiation and mass transfer due to copper vapour markedly cool down the central arc plasma whereas the influence of increased electrical conductivity is relatively small. The visualized simulation for the energy balance of fault arc shows that the presence of copper vapour has little influence on pressure rise.