Reliability and Cost-Benefit Analysis of a Power Plant Comprising two Gas and one Steam Turbines with Scheduled Inspection

A reliability model for a power generating system comprising two gas turbines and one steam turbine is developed wherein scheduled inspection is done at regular interval of time for maintenance. Initially, all the three units i.e. two gas turbines as well as one the steam turbine are operating and working of the system is called the working at full capacity. On failure of one of the gas turbines with steam turbine working, the system works at reduced capacity. If both the gas turbines get failed, the system goes to down state, whereas on failure of steam turbine, the system may be kept in the up state with one of the gas turbines working or put to down state according as the buyer of the power so generated is ready to pay higher amount or not and this is working in single cycle. Three types of scheduled inspection, that is, minor, path and major are done in this order at regular intervals of time for maintenance. System is analyzed by making use of semi Markov processes and regenerative point technique. Various measures of system effectiveness such as mean time to system failure, availability at full capacity, availability at reduced capacity, availability in single cycle, expected down time, expected time for minor, path and major inspection, busy period for repair and expected number of visits have been obtained. Costbenefit analysis has been carried out. Graphical study has been made and interesting conclusions are drawn. Key Words—Power Plant comprising Two Gas Turbines and One Steam Turbine, Scheduled Inspection, Reliability, CostBenefit