Gas Path Analysis And Exergetic Diagnostics For Gas Turbine Health State Determination

The use of computer aided diagnostic tools for gas turbine condition monitoring requires the development of methodologies capable to predict machine performance. Among the various techniques, Gas Path Analysis (GPA) and Exergetic Diagnostics Analysis (EDA) methodologies have received great attention in recent years and have both shown good capability to be used as diagnostic tools. The GPA methodology determines the gas turbine operating state by means of the calculation of the characteristic parameters (such as efficiencies, characteristic flow passage areas and pressure drops along the gas path) that are health indices of the machine. The diagnostic procedure based on exergetic and exergoeconomic analyses (EDA) is aimed at evaluating the impact of each malfunction on the overall efficiency and production costs or revenues. In this paper, the authors present a first step to integrate GPA and EDA, in order to increase the reliability of energy system diagnosis. A generator-drive single-shaft gas turbine is considered as test case. The analysis is aimed at comparing and discussing the complementary information which can be obtained by using the two different methodologies.