Reliability modeling and availability analysis of combined cycle power plants

• New reliability models for three types of thermal power plants (GTTP, STPP, CCPP) are developed.
• Mathematical expressions are derived for availability analysis of the plant components.
• Reliability-oriented sensitivity analysis is proposed to identify the critical components.
• The recognized critical components will take the lead in maintenance/asset management programs.
• Proposed approach helps the operator to better manage the investment plans when/where necessary.

Power plant successful operation is always a function of its constituent sub-systems and components. Due to the current financial constraints in power industry, power plant operators are continuously facing a wide range of challenges when dealing with maintenance scheduling and asset management practices of the plant sub-systems. Knowledge on the roles and criticality of the constituent components on the plant overall performance will help in establishing the plans for its smooth, safe, and economic operation. To ensure making the techno-economical decisions on the maintenance of power plant equipment, this paper focuses on the reliability modeling of the combined cycle power plants (CCPP). Reliability models are first developed for the gas turbine power plants (GTPP) and steam turbine power plants (STPP) which provides the input to evaluate the reliability of the overall CCPP from an engineering system perspective. Reliability-oriented sensitivity indices are proposed the aforementioned types of power plants to identify the plant critical components, i.e., those with the most considerable influences on the system reliability and availability targets. Having the system critical components recognized, one can then decide on the efficient maintenance strategies for the power plant components so that the available resources can be well planned and allocated techno-economically.