Development of Support Program for Managing Assets by Considering Regular Maintenance Cost and Statistically Expected Failure Cost

摘要

The asset management technique, which was developed in the field of financial engineering, is expected to rationalize business operations. There have been some previous investigations on introducing this technique into the maintenance divisions of electric power transmission and distribution facilities in Europe. Therefore CRIEPI (Central Research Institute of Electric Power Industry) is examining its effective introduction into Japan in the last about 15 years by referring to these investigations. In this paper, the evaluation is in terms of cost. Two types of cost, the maintenance cost in ordinary operation and the failure-handling cost including a penalty cost of electric outage, are considered in this investigation. The basic concept and a support program used to select better maintenance scenarios for an oil-immersed power transformer are described in this paper. The candidates are the successive operation of aged equipment by repairing it whenever possible or by large-scale repair (overhaul) until expected lifetime, and replacement by new, low-maintenance-cost equipment immediately or at a certain age. The cumulative maintenance cost is calculated for each scenario as the NPV (Net Present Value). In replacement scenarios, the depreciation is considered for realism. At present, the maintenance cost characteristic and the failure probability by age, which should be input to the support program as parameters, are under investigation. The method and difficulties are also described.