Application of GPA to Combined Cycle Gas Turbine Plants

Abstract

This paper investigates the possibility of applying a new technique called Gas/Steam Path Analysis (GSPA), that is based on the principles of Gas Path Analysis (GPA), to gas as well as steam turbine plants (as one unit) that are main parts of a combined cycle power plant by way of simulation. In order to facilitate this investigation two pieces of software were developed at Cranfield University. With this technique, it was possible to monitor the major components of the combined cycle, and hence predict the faults that may occur within the cycle beforehand. Faults looked at were, fouling and erosion of gas and steam turbine units, heat recovery steam generator degradation (scaling and/or ashe deposition), and condenser degradation. The obtained results from GSPA calculations of the cases investigated showed that “GSPA” technique can be equally applied to either gas turbine cycle, steam turbine cycle, or to the combination of the two in a form of combined cycle. The procedure, assumptions made, and the results obtained are presented and discussed herein.