Optimization of no-load voltage waveform in hydro-generator by asymmetric poles

Improvement of no-load voltage waveform is one of the important problems for design optimization of generators and quality requirement of electric system. The no-load voltage waveforms of a 45MW hydro-generator are optimized with the asymmetric poles design including the eccentricity of the pole shoes or/and the damper bars, and the computations are implemented by 2D moving electromagnetic field-circuit coupling model. The results show that the tooth harmonics are weakened and the waveforms of the no-load voltage are improved observably when reasonable shifting the center of the pole shoes or/and the damper bars. The research has been applied to 3 large hydro-generators operating at the power stations.