The problem of mathematical description of nonlinear dynamical systems remains relevant today, especially given the need to build modern surveillance systems for complex technical objects, such as power plants. The use of polynomial operators obtained with the help of shortened Volterra series to solve this problem, as practice has shown, proved to be promising, because this method allows to display in the mathematical model both nonlinear and dynamic properties of systems. For further development of the method, it is advisable to analyze different approaches in order to build effective algorithms for obtaining and applying in the problems of monitoring the functioning of nonlinear systems.