Analysis of the interruption process of molded case circuit breakers

To the optimization design of molded case circuit breakers (MCCBs), it is important and necessary to simulate the interruption process and analyze the characteristics. A set of differential equations can describe the interactive coupled phenomena of electric circuit, electromagnetic field and mechanism motion system in MCCB. First, with virtual prototyping technology, the simulation model for the operation mechanism of MCCB can be built, and experiments have been carried out to verify its validity. Then, with the existence of electrodynamic repulsion force, the interruption process of,the MCCB has been investigated with the influence of arc voltage, closing phase angle, prospective current, mechanism starting motion time and blow open force. It demonstrates the proposed method is effective and is capable of evaluating the new design of MCCB products.