Turbo-generator life management and service technology

To reduce electricity generation cost, utilities, IPP and industrial users are strongly asking to minimize life cycle time cost and maximize utilization and effective operation of existing power units. To meet these requirements, we replaced the conventional interval-based life management of units with the new risk and condition-based life management to extend the inspection intervals and to shorten inspection periods, and realized the significant improvement in availability and the reduction in maintenance cost. We also clarified the mechanism of aged deterioration of stator and rotor coil insulation, and established the life estimation technology. We furthermore established and put into practical use the wet-beat deterioration life estimation technology for water-cooled stator bars. Regarding the enhancement use of existing units, we improved cooling technology and newly developed HTC (high thermal conductivity) stator insulation system resulting in substantial output increase and efficiency improvement. We have established the technologies for the 2-shift operation. In the early 80s, these technologies were applied to a large-capacity water-cooled unit of DSS operation. This unit is currently running satisfactorily after 20-year operation. It is important, should a failure occur, to immediately reach the root cause of the failure and take the appropriate corrective actions considering economy. It is possible to propose optimal corrections to meet the user needs by using a new failure analysis technique and a new method to evaluate the different approaches to correction. This paper presents a new life management concept and service technologies for turbo-generators.