Evaluation of the Possibility of Flaw Detection in Turbine Generator Stator According to Spectrum of Vibroacoustic Signal

Abstract

A method for the evaluation of vibration acceleration spectra of the components of an operating turbine generator stator with loosening defects according to the results of simulation modeling is described. The procedure is developed and the experimental determination of frequency characteristics of the accelerance of a powerful turbine generator stator design from the loosening defect location to stator housing is given. The procedure is intended for the turbine generators of power plants on overhaul and/or testing facilities of manufacturing plants and employs impact excitation using an exciter that is not attached to the structure. The configuration of measuring facilities is given and the measurement error of the frequency characteristics of the calibrating unit is evaluated. The frequency characteristics recorded from four stators of turbine generators of TVV-320-2 type with different technical positions of mounting attachments and service lives are compared. The parameters of the check on measurements are evaluated. The possibility of the evaluation of the frequency characteristics of stator on a turbine generator of each type is shown. The installation diagram of sensors on the stator housing, which provides the defect location with the exactness of up to the sector of circumference of the stator with the central angle of 90°, is rationalized. The estimates of the frequency characteristics of the stator can be used for simulation modeling of vibroacoustic oscillations of the operating turbine generator stator housing with loosening defects. The aim of this work is to evaluate the possibility of the stator defect location and determine spectral diagnostic properties of faults. Drawbacks of the instantaneous impact model are shown and the examples and recommendations are given on the generation of dynamic models of the defects of stator.