Numerical Solution of Foundation Loads and Structural Deformation in Stator Frame of Vertical Hydrogenerators with Oblique Steel Columns

Nowadays, using oblique arms and columns in the structure of large hydrogenerators has many advantages such as thermal expansion without large mechanical stresses, foundation load reduction, oval air-gap prevention, and etc. Therefore, in this paper the use of oblique columns in the stator-frame of a large hyrogenerator in comparison to a traditional structure (i.e. stator-frame with radial columns) is investigated for the first time by developing a Finite Element inhouse program. The use of this inhouse software reduces the time of modeling of complex structures of large hydroelectric power generators and heavy analysis of commertial softwares significantly, and helps to develop a preliminary design and structural analysis of this type of generators. In this paper, the effect of number, dimensions, and angle of oblique columns on foundation loads and structural deformation in stator-frame are described and the optimum values are obtained. The results of this study show that, the application of oblique column technology has significant advantages in reducing foundation forces, reducing the natural frequencies, and uniform structural deflections.