Decisions for maintenance-intervals of equipment in thermal powerstations, based on few data

摘要

This paper describes a maintenance scheduling for pump systems innthermal power stations in order to reduce the maintenance cost duringnthe whole period of operation, while keeping the current reliabilitynlevel of the pump system. The dimensional reduction method is used tonsolve the problem in which a few available data are used together withnother factors relating to the failures of pumps. The problem, that thenavailable data are limited to a short range of the operation periodncompared with the mean time to failure, is solved by extrapolating thenwhole distribution of period of failure using available actual data.nWeibull distribution approximation is used for this purpose: the datananalyzed for failure and population statistics are those of 569 pumps,nduring the past 17 years which were recorded at 19 thermal powernstations owned by Kyushu Electric Power Company. The results of thenanalysis by the proposed method provided the most suitable maintenanceninterval for each pump, and hence are helpful to reduce the expense ofnunnecessary maintenance