Nonlinear modal interaction analysis and vibration characteristics of a francis hydro-turbine generator unit

The Francis hydro-turbine generator unit (FHTGU) is a typical nonlinear system with the coupling hydraulic, mechanical and electric subsystems. It challenge to understand reasons for its operational failures because major reason involves complex interactions of three Subsystems’ model interaction method normal forms has been well developed investigated, overcoming linear methods used in FHTGU’s stability analysis. However, these have not quantify higher-order terms mathematically accurate type capture dynamic modal between Due accelerating expansion hydropower stations, FHTGU shows singular oscillations new be upgraded cope this situation. In study, introduced analyze subsystems, results given by different are compared verify method’s feasibility. effect second order modes quantified investigate on characteristics FHTGU, vibration affected wind generation also investigated. result that intensity can effectively reduced satisfy stable requirements. All provide theoretical guidance operation FHTGUs.