3AT型断路器灭弧室瓷套断裂故障机理分析

Study on Fracture Failure Mechanism of 3AT Circuit Breaker Arcing Chamber Porcelain Bushing

3AT型断路器灭弧室瓷套断裂事故时有发生,严重危害设备及电力系统的安全稳定运行。为了研究断路器瓷套断裂的故障机理,根据质量守恒原理推导了水结冰膨胀数学模型,基于电-热-结构多场耦合有限元法建立了瓷套断裂数值计算模型,利用该模型分析了不同程度渗水结冰膨胀条件下断路器灭弧室瓷套的应力分布,研究结果表明,当瓷套胶装水泥局部含水率超过11.86%且发生结冰时,瓷套最大应力将超出瓷质材料的断裂极限。结合3AT型断路器灭弧室瓷套断裂事故的实例进行了验证分析,揭示了胶装区域发生渗水结冰膨胀是该型瓷套发生断裂的故障机理。

The fracture accidents of 3AT circuit breaker arcing chamber porcelain bushing happened occasionally, and it have a serious impact on the safe and stable operation of the power system. In order to study the fracture mechanism of this series of porcelain bushing, the mathematical model of water freeze expansion was deduced out according to the principle of mass conservation, and the fracture numerical calculation model of the porcelain bushing based on the electrical-thermal- mechanical coupled-field element method was established, the stress distribution of the circuit breaker arcing chamber porcelain bushing under different degree of ooze water freezing expansion conditions was analyzed, the results show that the maximum stress of the porcelain bushing would exceed porcelain material fracture limit when the water content of porcelain bushing cement compo exceeded 10.95% and happened to freezing. Combined with the specific case study of the 3AT circuit breaker arcing chamber porcelain bushing fracture accident, revealed that the seepage water freezing expansion at the binding area of porcelain bushing was the fracture mechanism of this series of porcelain bushing.