Simulation of Pressure Rise in Arc Chamber of MCCB During its Interruption Process

Pressure rise of the gas due to high current arc in the arc chamber of molded case circuit breaker (MCCB) may accelerate the arc movement and improve the corresponding interruption performance. However, this pressure rise may result in a heavy stress on the enclosure of the arc chamber. The paper is devoted to calculate the pressure rise and analyze its characteristics. Based on thermodynamics and ideal gas law, the pressure rise variation with time could be calculated taking into account the influence of arc current, venting size, splitter plates and gassing material. Relevant experiments also were carried out to verify the proposed calculation method. It demonstrates that the pressure rise in the arc chamber will be increased with the higher arc current, less venting and the existence of gassing material.