Prediction of forces on the retaining structure of hydrogenerators during severe disturbance conditions

Abstract Methods are presented for the prediction of torques, and tangential and normal forces acting on the retaining structure of hydrogenerator units as a result of severe disturbance conditions. Such calculations are necessary to secure the safe structural design of a hydrogenerator station. The torsional transient studies are based on the three-phase coordinate formulation for a synchronous generator together with a representation for the control system and prime-mover. Rotor-to-stator attraction forces are derived in a finite element analysis of the air-gap flux density in the generator. The paper reports results from a series of studies based on a practical 117 MVA hydrogenerator unit of the Greek Power System.