Crushing Stresses on Hollow Conductors in Large Watercooled Generator Stator Slots

The hollow strands in water cooled generator stator slots are subjected to heavy mechanical stresses during transient fault conditions. A mathematical model and analysis are developed in this paper to calculate the deflections and the stresses on the bottom most hollow strands at Roebel transpositions which experience the maximum crushing loads. The deflections at the middle of the hollow span are found to be small. The relative stress magnitudes are plotted over the practical range of the design parameters. The most interesting revelation of this study is that the crushing stresses do not monotonically increase with the hollow span, which is contrary to what might be expected.