3. Scheduled maintenance

Maintenance operations on any industrial plant can be divided into two categories:

• palliative maintenance (repair strictly in response to damage);

• preventive maintenance (repairs carried out before damage occurs and scheduled according to a method for assessing the degradation of the weakened part).

This paragraph explains why sophisticated methods are used to determine preventive maintenance operations on combined-cycle power plants, but mainly on combustion turbines.

Combustion turbines, whether installed as stand-alone units or in combined-cycle power plants, are designed to generate peak or semi-base load energy, or even to back-up the power grid. As such, they need to be up and running quickly, which places high thermomechanical demands on the...