Unbalanced Magnetic Pull in Large Hydrogenerator for Different Operating Conditions

Based on practical structures of the windings and core of large hydrogenerator,this paper presented a numerical method to calculate the magnetic field distribution and unbalance magnetic pull(UMP) by the method of two dimension finite element in the whole calculating region taking into account the saturation.As a case study on a 240MW hydrogenerator of 88 poles,the UMP caused by eccentric rotor or a half of exciting windings fault for different load are computed,and then analysis of influences of the eccentricity and exciting current on the UMP has been undertaken.