Finite Element Modelling of Big Turbo-Generator Rotor Vibrations using Newmark-beta Integration Method

In this paper big turbo-generator rotor vibrations are simulated for various electrical faults. Newmark-beta method is used to simulate the vibrations at various critical sections of the rotor. Rotor is modelled using finite element method with solid, hollow and tapered elements. Torque in the generator during the course of electrical faults is modelled using dq0 formulation and solved in MATLAB using 4th order predictor-corrector method. Line to ground (L-G), line to line (L-L), three phase (L-L-L) and asynchronization faults are simulated for 300msec. The torsional vibrations in rotor at critical section is found to be most severe during three phase fault followed by mal-synchronization fault followed by the line to line fault followed by line to ground fault.