GEC Alsthom policy in generators maintenance and refurbishment

For a large number of turbo-generators, the limit of their service life initially expected is or will be reached. The various economic, political and ecological considerations do not militate in favour of the construction of new large power plants. This leads to the extension of the service life of existing generators beyond 40 years. In parallel, the need for electric utilities to reduce their maintenance costs leads them to opt for conditional maintenance, to extend the internals between overhauls, to reduce the shut-down periods, while keeping a high level of reliability for the equipment. As the availability of a machine is dependent on many factors, and in particular on the sequence of periodical maintenance, the repair methods and the availability of spare parts, the authors have carried out a reliability study in order to deepen and validate the acquired feedback of experience.