Recent concerns for the frequency quality in the Nordic power system has lead to an increased interest in hydro turbine governors. Among this research have been papers on identification of turbine and turbine governor dynamics from PMU measurements. However, no attempt at a theoretical validation has been made. This paper fills in this gap by a theoretical validation using a DC power flow model for modelling the power flows in the grids. By doing this it is shown that it is indeed possible to identify the closed loop transfer function of the turbine, turbine governor and electromechanical dynamics. An experimental validation using results from a real life power system is also presented.