Possible input data of a NPP power unit model for matching model states with prototype states are considered. The most important parameter used to match the states is the thermal power of the reactor unit (RU). Methods for accurate setting of the reactor plant power in the model were examined, namely, by using an automatic power controller (APC) and a mathematical boron controller. As part of matching the state of the nuclear power plant model with the prototype, a numerical experiment was carried out using PROSTOR, a full-scale simulation facility. The experiment was intended to obtain stationary states of the model with power in a range from 94% to 104% with a step of 0.05%. For modeling, the data pertaining to load 3 of unit 4 of the Kalinin NPP on the 248th effective day were used. In analyzing the results of a numerical experiment, two effects were discovered. One of them, exhibited in the derivative of the resulting plot of the dependence of pressure in the steam generator on power, is associated with reaching the upper limit of the capacity to control the pressure in the main steam collector (MSC). The control element of the pressure controller in the MSC is the control valves on the turbogenerator. At the moment that corresponds to the kink on the plot, they fully open, owing to which pressure control is no longer possible. The pressure in the MSC begins to rise. This effect corresponds to real processes occurring at nuclear power plants. In this case, it is proposed to use as one of the parameters of the model settings an adaptive coefficient to the concentration of boric acid in the reactor and control it by means of a mathematical boron controller. The second effect is that the pressure in the reactor cannot be accurately controlled because of the operating characteristics of the automation of tubular heating elements of the pressure balance (THE PB). In relation to this, it is proposed to use an additional mathematical controller of THE PB to match the state of the model with the prototype. These controllers have been successfully tested as part of the PROSTOR software package for matching the power of the reactor unit and the prototype.