Large 60 Hz turbogenerators: Mechanical design and improvements

In order to follow the market demands for the power generation industry, turbogenerator designs for today´s applications must be cost effective, highly reliable and highly efficient. To meet these challenges, Alstom introduced the first GIGATOP 2-pole and 4-pole turbogenerators 40 years ago, for fossil-fueled plants and nuclear power plants, applications in 50 Hz and 60 Hz markets. Since then, these turbogenerators have been continuously developed by Alstom. The GIGATOP turbogenerator has specific design features such as direct water-cooled stator bars with stainless-steel cooling tubes, to achieve high reliability and efficiency. In this paper, technology improvements of GIGATOP turbogenerators are presented, with the focus on mechanical design. Best industrial practice, in terms of tools and methodologies, are applied to ensure a smooth development process and improvements of the GIGATOP design towards further increases in performances, while maintaining and enhancing the outstanding levels of quality and reliability.