Performance Guarantee and Testing of Steam Turbine Retrofits

The steam turbine retrofit business has grown in recent years, largely due to advances in the aerodynamic design of steam path components, to the point that retrofitting non-OEM equipment is now common place within the industry. This paper discusses different steam turbine retrofit scenarios and how improvements in component performance translate into tangible power and heat rate benefits for plant operators. Methods for guaranteeing the performance of steam turbine retrofit cylinders, that allow the guarantees to be verified by testing approaches that minimize expense and uncertainty are described. Depending on the retrofit solution, guarantees may be simple turbine cylinder efficiency guarantees, performance improvement guarantees or absolute performance guarantees. Different types of testing are appropriate to verify these different forms of guarantee, and they are discussed in the paper.