Electromagnetic Forces and Mechanical Oscillations of the Stator End Winding of Turbo Generators

Abstract

Abstract. Numerical methods of calculating the electromagnetic forces and of simulating the oscillation behavior of the stator end winding are introduced. The end winding oscillations of different turbo generators under forced vibrations are computed in a combined simulation. Also eigenfrequencies and eigenmodes are determined. The obtained results are surveyed by measurements. Numerical simulation of oscillation behavior is found a useful tool in end winding design although model parameter identification still offers improvement potential.

Numerical simulation of the end-winding deformations in the synchronous machine under symmetrical short-circuit conditions using FEM*

“…The assumption has been made that the field components provoked by the short-circuit stator currents dominate over the rotor fields. However, the numerical procedure presented in this paper can be further improved by approximately taking into account the rotor excitation by the method of a fictitious rotor winding as presented in (Grü ning and Kulig, 2006).…”

“…This way the modeling procedure is simplified to some extent and also the computational costs are noticeably reduced. In (Grü ning and Kulig, 2006) a similar approach to the end-region magnetic field computation has been applied in order to calculate magnetic forces and corresponding end-winding deformations under short-circuit conditions. The presented procedure is very time-efficient, but the material non-linearities and induced eddy-currents in the clampingplates of the generator are neglected or only indirectly considered using this procedure.…”

Development of a new simulation tool for computation of the synchronous generator end-winding deformations

“…The assumption has been made, that the field components provoked by the short-circuit stator currents are predominating over the rotor fields. However, the numerical procedure presented in this paper can be further improved by approximately taking into account the rotor excitation using the method of the fictive rotor winding as presented in [3].…”

“…Despite this fact, in the literature different endeavors to the analytical computation of the magnetic field in the machine's end-region are introduced [1] and [2]. Alternatively, in [3] a numerical approach has been applied in order to estimate the end-winding deformations. The presented procedure is timeefficient, but the material non linearities and eddy-current effects are neglected or only indirectly considered.…”

Influence of End Structure on Electromagnetic Forces on End Winding of a 1550 MW Nuclear Generator

“…Simplifying the end coil as straight line inductors, Richard et al [16,17] calculated the electromagnetic force on the end winding of a 600 MW turbogenerator using the 3D electromagnetic model of the stator end region. Senske et al [18], Drubel et al [19], and Grüning and Kulig [20] calculated the electromagnetic force on end winding based on the Biot-Savart law to line circuit segments. Albanese et al [21] proposed a numerical approach based on an integral formulation to calculate the magnetic field and forces on the end winding of a large generator.…”