Diagnosis of turbine generator typical faults by shaft voltage

Relationships between shaft voltages and static eccentricities are studied, theoretical analysis shows that shaft voltages are induced by the `distorted fluxes´ caused by static eccentricities, shaft voltages mainly contain odd harmonics, the harmonic amplitudes increase under greater eccentricities. Some new distorted flux hamonics appear when field windings interturn short circuit happens, the harmonic frequencies change with the generator pole-pair number, and amplitudes increase when the fault get worse. The following experimental work agrees with the theoretical predictions.