Stator frame distortion: Living with alkaline aggregate reaction (AAR) on the concrete structures of hydro-electric dams; A case study of at kpong hydroelectric station, Ghana

The most probable cause of the generator and throat ring distortion is concrete creep due to the alkaline aggregate reaction. Generator designs incorporating stator frame integral sole plate embedded parts can be successfully modified in situ, by introducing radial keys instead of the original radial pins and stopper blocks with tapered wedges or keys, to a radial freedom design, thus alleviating the effects of any concrete creep induced distortion. Introduction of a load cell system in between the lower bearing bracket (LBB) arms to measure compressive stresses also make it possible to adjust the compressive stresses in the LBB arms. Thus alleviating the effects of concrete creep.