Analysis of steam blockage faults of large turbogenerator circular lead

Steam blockage faults inside the circular lead of large turbogenerators, which initiated by some installation mistakes, will burn the lead and cause a non-normal shutdown accident. According to specific fault cases, the conjugate heat transfer model of the lead and its cooling water was constructed in this paper, based on the computational fluid dynamics. Thermal field of the lead and its water under a wrong return pipe connection was calculated, and then the relationship between temperature characteristics and the degree of blockage was analyzed. The calculation and analysis results indicated that, the abnormal low flow rate caused by a wrong return pipe connection was the direct reason of steam blockage. The lead began to melt about 30 min after the formation of steam blockage. On this basis, this paper suggests a normative installation and extra thermal and flow monitor devices to prevent faults.