ABSTRACT
A considerable part of power plant engineering comprises application of major engineering disciplines of thermodynamics, fluid mechanics and heat transfer to steady-state performance calculations at a fixed design point characterized by site ambient and loading conditions. Yet, a real power plant, once constructed and commissioned, rarely operates at that particular design point. Consequently, off-design and unsteady-state performance estimation, analysis and optimization are vital to a successful power plant product during the design and field operation phases. These aspects of combined cycle technology are covered under the heading of operability. This chapter provides a detailed look into off-design plant performance under steady-state and transient operating conditions. Major plant transients such as startup, shutdown and response to grid disturbances as well as emergencies such as plant trips are discussed in detail with the help of quantitative and qualitative information including tables and charts.
