Application of Composite Spectrum in Steam Turbo-Generator Set

Abstract

Composite spectrum and composite bispectrum techniques have been recently developed for identifying fault(s) in rotating machines. The fusion of the measured vibration data at all the machine bearings in the frequency domain is used to construct such a composite spectrum and composite bispectrum for the representation of the entire machine. These techniques are now applied to a Turbo-generator (TG) set which consists of a high pressure (HP) turbine, an intermediate pressure (IP) turbine and 3 low pressure (LP) turbines in addition to an exciter and a generator. Earlier study using the spectrum analysis of the measured vibration acceleration data on the bearings of the TG set during machine normal operation indicates the possibility of the rotating stall in LP turbines and misalignment between the IP and LP rotors. The observations and results of the current study also indicate the presence of localised misalignment and suspected rotating stall in the composite spectrum.