Nonlinear modeling and dynamic analyses of the hydro-turbine governing system in the load shedding transient regime

Abstract

Load shedding processes are widespread in hydropower stations, which has great influence on the safe and stable operation of the hydro-turbine governing system. In order to study the dynamic characteristics of the hydro-turbine governing system during the load shedding process, a novel nonlinear mathematical model of the hydro-turbine governing system is established considering the hydro-turbine system, the generator system and the governor system. In particular, a novel nonlinear mathematical model of the six hydro-turbine transfer coefficients is presented based on the definitions and hydro-turbine internal characteristics. After that, from the viewpoint of nonlinear dynamics and the practical engineering, the dynamic characteristics of the hydro-turbine governing system are investigated utilizing bifurcation diagrams, time series, Poincare maps, power spectrums and phase planes. Some meaningful results are found. The advantages of the novel nonlinear mathematical model are illustrated and commented in detail in comparison with the previous model. Finally, these models and analysis results will provide some theoretical references for the operation of hydropower stations in the load shedding transient.