Contribution of Opening Speed of SF₆ Gas Circuit Breaker for High Temperature Area Decrement Using Three-Dimensional Electromagnetic Thermal Fluid Simulation

The arc extinguish chamber of SF₆ gas circuit breaker is expected to be smaller than the current one, while the thermal reignition can be prevented. It is important to obtain the rapid change of temperature distribution inside the extinguish chamber during the interruption process. However, it is difficult to obtain the rapid change of arc plasma with experiment, the numerical simulation is usually used to analyze the above process as well. Meanwhile, the temperature volume of arc increases along with the electrode opening process during the actual interruption process of circuit breaker. Therefore, it is necessary to consider the electrode opening process for analyzing the thermal reignition. The most difficult part of simulation for the electrode opening process is the treatment of interface between arc plasma and electrode, because the rapid change of physical properties with time variation. In this research, a calculation method of electrode opening process was proposed for high temperature area decrement. As a result, the high-temperature region decreased significantly when the electrode opening velocity was fast.