An Investigation of a Turbo Generator Foundation Failure at a Higher Power Generation State

Abstract

All analysis, studies, techniques, criteria, and methodologies presented and described in this paper are based on an actual engineering project as an example. For the generation of electricity, the boiler, turbine, and generators (BTG) work together in any thermal power plants. Fossil fuels such as coal, gas, or oil are required for power generation. In a project in India, for the designing of a turbo generator (TG) foundation required for a 120 MW BTG gas based captive power plant, it has been observed that up to the power generation of about 100 MW there is no problem in operation of the TG, but beyond 100 MW of power generation vibration of the shaft exceeds the limit recommended by the TG supplier. This called for an investigation of the correctness of the exiting design of foundation based on the load data supplied by the equipment supplier and requirements of the modification of the existing TG foundation. The dynamic analysis of turbine foundations needs attention to detail in both modeling and interpretation of the results to examine the deficiency, if any, in design that may be the cause of excessive vibration in the machine and foundation system. The paper presents the results on various issues related to the mathematical modeling of the structure, machine, and soil for dynamic analysis as well as static analysis of the foundation system. The finite-element method provides an efficient tool for the modeling and dynamic analysis of TG foundations. Structural analysis and design (STAAD) connect provides a real computational environment for the modeling of the structure, machine, and soil in a single model and to perform free and forced vibration analysis. Investigation shows that the design of the TG foundation satisfies all the codal provisions and the requirements of the equipment supplier. Also, the test results show that the vibration amplitudes of the TG deck and the columns are well within the permissible limit. Hence, it can be concluded that the design is adequate for the proper operation of the machine. The excessive vibration in the foundation may be due to the misalignment of the shaft at higher power generation state. The findings of this study have practical implications for the design, maintenance, and operation of turbo generator foundations in power plants. By identifying the critical factors that influence vibration behavior, such as shaft alignment and soil–structure interaction, this research provides actionable insights for engineers and contractors. Improved foundation design: The study demonstrates the importance of incorporating dynamic and static analysis during the design phase to ensure vibration levels remain within permissible limits, especially for high-capacity generators. Enhanced installation practices: the observed excessive vibrations were linked to shaft misalignment during installation. This highlights the need for precise alignment procedures and quality control to avoid operational disruptions. Sustainability in power generation: by optimizing foundation performance, the study contributes to reducing equipment wear and tear, minimizing downtime, and ensuring reliable power generation at higher capacities.