SELECTION OF MAINTENANCE STRATEGY FOR GAS TURBINE SYSTEM IN COMBINED CYCLE POWER PLANT

Abstract

More than forty percent of electricity in Thailand is generated from combined cycle power plants. This type of power plant uses a combination of gas turbine and steam turbine systems. From the study of the past 2.5 years of the power plant case study found that the gas turbine system caused the power plant to shut down suddenly, accounting for 88.7% of all sudden downtime. This research focused on strategy maintenance improvement in gas turbine system by analyzing the criticality of the equipment to determine the appropriate maintenance strategy. The analysis results could be divided into 4 levels of criticality, 278 items of level A, 94 items of level B, 197 items of level C, and 267 items of level D, representing 33%, 11%, 24%, 32% respectively. Use a proactive maintenance (PaM) strategy for devices with critical A level. Use preventative maintenance (PM) strategy for devices with critical B levels. Use a corrective maintenance strategy (CM) for levels C and D. After implementing the maintenance strategy for one year, the results showed that the average value of sudden breakdown of the power plant decreased from 2,371.48 hours per year to 1,094 hours per year, representing a decrease of 53.86%.  The availability of power plants increased from 86.18% to 93.18%.