Variation of reactances related to the main flux under internal short circuits of turbogenerator stator winding

摘要

Analysis of changes of reactances of individual parts of turbogenerator stator winding in dependence on the number of shorted turns has been conducted in the paper. The analysis concerns the reactances related to main flux of the stator double-layer lap winding with double winding per phase. The derived expressions take into account the spatial shift of the stator winding coils as well as the mutual shift of magnetic axes of individual parts of the damaged stator winding. As an example the reactances as well as amplitudes of short circuit currents (periodical component of fundamental frequency) for the steady state of a theoretical symmetric three-phase short circuit in the stator winding when a turbogenerator is connected directly to power system of infinite power were calculated. Results of calculations of the short circuit currents have been compared to measurements conducted for a turbogenerator physical model.