Analysis of Interruption Characteristics of DC Miniature Circuit Breaker with Different Structures

Direct current (DC) miniature circuit breaker (MCB) is a crucial component for controlling and protecting the DC power system, especially in photovoltaic power generation system. In this paper, experiments under various current are carried out in different structures of DC MCB. Except arc current waveforms, the arc images during the interruption process are recorded by CCD. The interruption characteristics are analyzed. Also, a 2-D magneto-hydro-dynamic (MHD) model for the relevant MCB is developed. Based on the model, the effects of arc current, arc quenching chamber on the arc evolution process are analyzed. The experimental phenomena are well explained based on the simulation results. It is showed that the MCB with tilting contact has better breaking capacity due to the airflow acceleration effect of tilting contact, and the developed model could be used to optimize the design of the arc quenching chamber and contact system of DC MCB.