Lifetime Prediction for Hydro Generators

Abstract

This thesis concerns lifetime prediction of hydro generators and how different operational and environmental factors affect the lifetime. A method for predicting the remaining lifetime, using information on it's design, operational history and condition, is introduced and tested.

Determining the condition of the stator winding and core insulation systems is vital for any attempt to lifetime prediction for hydro generators. Information on the condition can be obtained by visual inspection, diagnostic measurements and condition monitoring methods.

A method to predict the remaining lifetime of hydro generators considering the statements above is explained. The method is used to predict the remaining lifetime for two generators in Steingrimsstöd hydro station in Iceland. Only information from 1995 and older is used in the prediction. In this way the predicted lifetime can be compared to the real experience of the generators.

The results show that the lifetime prediction for the test specimens does not match the reality accurately. The method does however determine the insulation condition and diagnose the failure modes correctly. The exact time of failure is not only governed by the machine condition but other unpredictable factors as well.