SPECIFYING & EVALUATING STEAM TURBINES IN COMBINED CYCLE APPLICATIONS

The ASME Performance Test Code PTC-6.2-2004 provides for the testing of steam turbines in combined cycle applications. The acceptance criterion, called "Output Performance" is primarily a measure of efficiency. This paper presents a scenario that illustrates that efficiency alone is not always a sufficient criterion. In this case history, MW Output at the revenue meters suffered by nearly 10% and yet the PTC-6.2 efficiency criterion was satisfied.