Presentation of a system for the improvement of the on-line thermal monitoring on 900 MW turbogenerators for predictive maintenance purposes

This paper firstly presents an acquisition system which has been developed in order to rapidly detect the overheating in the stator bars of large turbogenerators in nuclear power plants; it has been installed in 1994 on the stator of Tricastin. Secondly, associated to it, the development of a new monitoring system is presented, based on the determination of the fingerprints of the stator from the thermal modelling of the water cooling circuit. Validated by the measurements made on site, it also enables the following in real-time of the status of the machine, provides a detailed diagnosis of it, and optimises the load in abnormal conditions. It may turn the actual maintenance made on those machines towards the concept of predictive maintenance.