Explicit modelling of the stator winding bar water cooling for model-based fault diagnosis of turbogenerators with experimental verification

Fault diagnosis for technical systems becomes more and more important due to the increased safety and reliability standards. Development in computer techniques and diagnosis methods allow problems of high complexity to be considered and introduction of state-oriented monitoring and maintenance scheduling becomes possible. This paper addresses the fault diagnosis problem concerning the individual stator winding bar water cooling of large turbogenerators. Obstruction of hollow partial conductors in the stator bars could lead to a severe thermal damage of the insulation. Therefore, it is important to detect the tendency leading to such a fault early. To obtain the necessary reference values for a sensitive real-time fault diagnosis, modelling the system behaviour is essential. The components of the physical model which have to be considered for such a sensitive model-based fault diagnosis are described in the paper. The experimental verification shows that the proposed model can be applied successfully