Improving life cycle management plans for power plant components

Life cycle management (LCM) combines a set of technical and economic activities with the specific goal of improving the long term economic value of an asset. It is necessary to perform a sound LCM exercise on the utility or industrial asset to maintain the profitability of a plant. In most industries, the maintenance budget is either higher than optimal or lower than required, that result in expensive outages, damages and accidents. An LCM plan is a guide to make operational decision for a component over its life cycle. LCM typically consists of a preventive maintenance schedule, condition monitoring, inspection activities, replacement or refurbishment plans and spares management. It is developed based on a study of component failure modes, operating history, maintenance practices, ageing, spares and obsolescence. Once an LCM plan has been formulated, it can be compared with other alternative LCM strategies in order to minimize the long term costs over the plant lifetime. Utilities predominantly develop life cycle management plans based on heuristic approaches. Existing work does not accurately cover the impact of maintenance on equipment reliability and cost. In this thesis, a state diagram is developed to simulate the aging, inspection, maintenance, repair, failure and overhaul cycle of a component throughout its lifetime. This diagram can help in deciding the optimal maintenance policy and also quantify the impact of maintenance on reliability and cost. Probabilistic tools are developed that help in the evaluation of an LCM plan and to further optimize the plans. A suite of software built for the LCM comprises of modules to: Estimate the failure rate using Weibull parameters Estimate the effect of maintenance on the Weibull parameters Calculate the life cycle cost based on maintenance cost, failure and replacement --Abstract, page iii