Effect of Generator Rotor Radial Deviation on the Unbalanced Magnetic Pull of 1000 MW Hydro-Generator Unit

The 1000 MW hydro-generator unit has huge geometrical dimensions and requires high installation accuracy. The control of its installation deviation will directly affect the installation quality and operational performance of the unit and the rotor eccentricity is one of the core problems faced in the installation and operation of the giant hydro-generator unit. This paper presents a method to calculate the asymmetric magnetic field by means of the transient finite element calculation to reveal the effect of the generator rotor radial deviation on the unbalanced magnetic pull of the unit. The effects of rotor dynamic eccentricity on the magnetic field are analyzed in the time and frequency domains, respectively. The results show that both the DC component and the key harmonic component of the unbalanced magnetic pull increase with the increase of the eccentricity value, and this variation relationship is nearly linear. when the eccentricity is no more than 0.15 mm, the unbalanced magnetic pull caused by the rotor eccentricity is calculated to be small, which is acceptable. The conclusions of this investigation can help to straighten out the requirements and standards for the installation deviation control of the large hydro-generator units.