Maximum Utilisation of Parts Process: A Method for Increased Precision of Component Lifetime Estimations in Medium Size Gas Turbines

The goal of a maintenance strategy should be to reach a Retirement For Cause, RFC, condition, where components are not replaced until a potential failure has been detected. Further, the inspection interval should be large enough to allow spare parts to be ordered and delivered during the time between failure detection and failure, with sufficient safety margins. This requires measurement techniques that can monitor how the turbine is operated, prognostics capabilities that foresee maintenance needs, and test methods that can determine the state of a component during maintenance events. In general there are two ways to determine the amount of damage a gas turbine component has been subjected to — calculations and examination of service exposed components. Optimum results should be obtained by using calculations as a basis and continuously review/modify their interpretation and the underlying damage models using best available experiences. This paper describes the Maximum Utilisation of Parts Process, MUPP — a process for systematic testing of used components, how process data can be turned into modifications to a gas turbines maintenance schedule with same or decreased risks, and the implications for equipment operator as well as maintenance provider. It is concluded that MUPP allows significantly lower maintenance costs in the medium to long time frame.