Analysis of Shaft Voltage of Large Turbo-generators for rotor defect detection purposes

In the case of large turbo-generators, the analysis of the shaft voltage could be interesting to diagnose some defects such as eccentricities or field winding inter-turn short circuits. To this aim, a first step consists in determining in an accurate way the effect of these defects on the shaft voltage. In this paper, a 4-pole high-power non-salient pole synchronous generator is studied in a didactic way. The study is carried out gradually, with the aim to determine the effect of the parallel coupling of the armature windings.