Modelling and Simulation of Low-Head Hydro Turbine for Small Signal Stability Analysis in Power System

The hydro turbine dynamics have a considerable influence on the dynamic stability of power system. In the study of dynamic stability, the system is modeled by the linear differential equations (small signal analysis). Small signal stability of power systems is needed in all conditions and only is dependent on the conditions of power system performance before commotion occurrence. This paper provides an analysis of the small signal stability in a hydropower plant equipped with low head Kaplan turbine connected as single-machine infinite-bus (SMIB) power system. The dynamical behaviors with representative characteristics are identified and studied in details. The model of system is described by state-space equations. The eigenvalues analysis is used to show the effects of change in parameters for damping load angle and speed oscillations through the excitation and governor subsystems. Finally, results of theoretical analyses are verified by time-domain simulations under different system conditions and operating loads.