SF_6自能膨胀式断路器开断大电流过程的数值模拟与分析  

Simulation of Heavy Fault Current Interruption in an SF6 Auto-Expansion Circuit Breaker

作　　者：张俊民[1] 

机构地区：[1]北京航空航天大学电气工程系,北京100083

出　　处：《电工技术学报》2004年第9期6-9,17,共5页Transactions of China Electrotechnical Society

摘　　要：在建立喷口电弧与喷口烧蚀蒸气相互作用的数学模型基础上,应用有限元方法数值模拟了SF6自能膨胀式断路器开断大电流的过程,计算并分析介质恢复过程。研究结果表明:膨胀室内压力的建立与燃弧过程密切相关,第二个电流半波的燃弧过程,对压力的影响较第一个电弧电流半波的大,是压力建立的关键过程。电流过零后灭弧室气流特性主要为:由于膨胀室内气流的作用,喷口喉部内形成一滞止区,弧隙间的温度迅速下降,喷口下游气流逐渐发展成超音速流。介质强度恢复特性表现为迅速上升的过程,而后为缓慢上升的过程;开断电流减小,介质强度恢复的速度快,介质强度高。Based on the mathematical model of the interaction between nozzle arc and ablated vapour, a heavy fault current interruption is numerically simulated on an SF6 auto-expansion circuit breaker by finite element method, and its recovery process of dielectric strength is analyzed. The results show that the pressurization in the expansion volume strongly depends on the arcing process. The crucial stage for the pressure established in the expansion volume is in the second half wave of arcing current, and its influences on the pressure are more serious than that of the first half wave of arcing current. The stagnation region is formed in the nozzle throat after current zero due to the gas flow from the expansion volume, and the temperature of the gap between moving contact and fixed contact is quickly decreased, and the supersonic flow is produced gradually at the downstream of the nozzle. The recovery characteristics of dielectric strength is rising quickly at the beginning stage of its recovery process and then increasing slowly along with time. There are higher dielectric strength and faster recovery process of dielectric strength when interrupting current decreasing.

关 键 词：电弧动态数学模型 膨胀室 气流场 介质恢复强度 

分 类 号：TM561[电气工程—电器]