Finite element analysis for hydrogenerators
35 Międzynarodowe Sympozjum Maszyn Elektrycznych. Maszyny Elektryczne w Energetyce. SME'99/sympozjum(XXXV; 1999;Kazimierz Dolny), Polska)
The electromagnetic characteristics of hydrogenerators are studied from the point of view of maintenance and condition monitoring. Fault conditions are modelled and simulated by time-stepping finite-element techniques. The parameters giving the best indication of a fault are searched from the results of the numerical simulations. The faults studied are short circuits in armature and field windings, static and dynamic eccentricities, shifted rotor poles and asymmetries in the geometrie shapes of the stator. The best parameters for detecting the faults are discussed. The large and complicated geometry of the hydrogenerator causes some problems for the analysis. A generator has typically 50-100 poles, and a simulation of a fault condition usually requires modelling the whole cross-sectional geometry of the generator. This means that even a simple two-dimensional finite element mesh contains 50 000-100 000 elements, and the computation times become very long. The possibilities to reduce the problem size and still maintain the accuracy needed for the purposes of condition monitoring are studied.
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