Diagnosis and Magnetic Field Analysis of Small Power Salient-Pole Synchronous Generator with Static Eccentricity Using Time-Stepping Finite-Element Method

This article presents a numerical simulation model for small power salient-pole synchronous generator under static eccentricity fault at no-load and full-load conditions using the two-dimensional time-stepping finite-element method. The influence of different degrees of the eccentricity fault on generator performances is described. Magnetic flux distribution within the generator, air gap flux density patterns under rotor poles shoe, and self- and mutual-inductances characteristics of the stator phases and rotor winding in both healthy and faulty conditions are determined. Fourier analysis of the air gap flux density under rotor pole shoes and no-load voltage profile is used to determine of the harmonic contents in the presence of the static eccentricity fault. In addition, spectrum analysis of the stator current is illustrated for on-line diagnosis of the static eccentricity fault. It shows that at the no-load condition with low excitation current, the effect of the eccentricity fault is considerable compared to that of the rated excitation current. It also shows that the presence of significant harmonics in the stator line current of faulty synchronous generators is dependent mainly on the generator design parameters. This will be proven by experimental and numerical results.