Performance analysis of a twin-shaft gas turbine with fault in the variable stator guide vane system of the axial compressor

In this study, an analysis of the performance of a twin-shaft industrial gas turbine (IGT) with a fault in the mechanism of the compressor that changes the position of variable stator guide vanes (VSGVs) is carried out. Measured field data of a twin-shaft engine denoting a difference (offset) between the demanded inlet guide vane (IGV) angle and the measured IGV angle in the axial compressor have been considered for the analysis. A validated Simulink model which simulates the performance of the twin-shaft engine has been considered for the analysis of the fault in the VSGV system. The Simulink model architecture comprises an axial compressor module and considers an multi-stage compressor performance map at optimal conditions (new & clean). The results demonstrate that it is possible to predict the physical parameters such as pressure and temperature measured across the different stations of the engine during the offset of the IGV angle. The effect of the IGV offset on the compressor performance is discussed as well. The change in compressor air flow and compressor efficiency at different IGV offset is discussed, as during a low power engine operation and fault within the VSGV system, the surge line may drift close to the compressor running operation line