Calculation of Arc Temperature Distribution with Changing Nozzle Shape

The arc temperature distribution with changing the nozzle shape in the double-flow type gas circuit breaker (GCB) was calculated with the 3- D electromagnetic thermal fluid simulation. The contribution of arc extinction is affected by the convection of arc to outlet of ring electrode with changing the nozzle shape. Recently, the stable and reliable supply of electric power has been indispensable for the industry with the sophistication of the industry. The accident current causes the instantaneous voltage drop when the accident occurs in the power system such as a lightning surge or short-circuit fault. The power equipments would be badly damaged by this phenomenon. Therefore, it is important to interrupt the fault current as soon as possible, and GCBs are used for current interruption. GCBs are used for interruption the current and protect the power equipments and power systems. The arc heated gas is exhausted in two opposite directions in order to extinguish the arc plasma. The arc is extended by the two opposite convections, and the gas flow improves arc quenching. It has been reported that the arc cooling caused by blowing gas in the axial direction to the arc in order to improve the characteristics of current interruption. The research of gas flow is important because the convection is a major source of energy loss in the double-flow gas circuit breakers. However, the convection to outlet of ring electrode for arc extinction in the double-flow gas circuit breaker is not elucidated. Thus, it is important to research the flow velocity with changing the nozzle shape in order to improve the performance of current interruption. In this research, arc temperature distribution was calculated with changing the nozzle shape. The parameter of this simulation is gas blaster angle. As a result, the convection to outlet of ring electrode increased when the angle of the upper nozzle increased. Moreover, the arc temperature decreased near ring electrode when the angle of the upper nozzle increased.