DYNAMIC BEHAVIOR OF TURBINE-GENERATOR-FOUNDATION SYSTEMS

In this paper a comprehensive investigation on the dynamic characteristics of turbine-generator-foundation systems is performed. All the major components of the system, including turbine-generator casing, shaft, rotors, journal bearings, deck, piers, foundation mat, piles, and soil medium, have been included. Full interaction between the turbine-generator set, the foundation superstructure, and the soil medium, is considered. A hybrid method is used to establish the mathematical model for the turbine-generator-foundation system. The analysis is conducted in the frequency domain through complex frequency response analysis. The response in the time domain is obtained by Fourier transform. The seismic excitation is represented as the control motion on the ground surface, which is generated as an artificial earthquake. A 300 MW turbine-generator-foundation system is analysed under excitations from rotor unbalances and earthquakes. The influence of turbine-generator casing and soil anisotropy on the response of the system is explored. It is found that the presence of casing and soil anisotropy strongly influences the displacements and internal forces of the system under rotor unbalance excitation. Under seismic excitation, however, although the presence of casing and soil anisotropy does affect the displacements of the system, their effect on the internal forces of the system is minimal.