Managing environmentally stressed aging assets in electric power utilities
MetadataShow full item record
A model for optimizing the differential cost between a preventive maintenance program and a traditional run-to-failure program on managing assets under uncertainty is developed to assist electric power utilities in decision-making. The assets studied, though not necessarily critical to power delivery, are so numerous in number that the failures of thousands of them result in millions of dollars in instantaneous replacement cost to the utility. The ages of some of the assets are approaching an excess of one hundred years, the age of commercial electricity in the United States. The developed model includes the economics of inspections and replacements as random variables, where the cost of corrective replacements could significantly exceed the cost of planned or preventive replacements. The model also relies on uncertainties in annual failures and inaccuracy of diagnostics that drive planned replacements. Age-specific fragilities of the assets under environmental stress are assessed, and the likelihood of failures of the assets was found to increase significantly as they approached one hundred years, past some initial age of failures that are comparable to new assets. This finding led to the development of an improved geographical inspection scheme, where only components past that initial age are recommended for diagnostic evaluation. The optimization results suggest that the present net benefit/cost of preventive replacement programs of the electric power utility to the unpopular run-to-failure program can be improved on. This, by using the developed models and adopting the frameworks presented in the research work. Implications for future research are also discussed.