The paper sets and solves the problem of: the power unit power stabilization system in accordance with the specified value; and increasing the efficiency, parametric optimization of autonomous control systems was performed, both for conventional and prognostic ones, with an assigned stability margin for the minimum of the linear integral criterion. For a correct solution, the combined influence of one system on another through the object was taken into account. Modelling and research of the system with a static compensator from the fuel regulator to the feedwater flow regulator were carried out. It is shown that the connectivity of the system leads to the appearance to undesirable oscillations. To eliminate the drawback of conventional systems, it is proposed to switch to prognostic regulators. The object of the study is an 800 MW power unit. The dynamics are obtained on the basis of experimental data.