The construction of automated systems intended for the control of electric power systems requires high-speed mathematical tools. The research is aimed at developing algorithms for the construction of automated systems to control active components of the electrical network. The method applied by the authors to describe the object of control is based on the universal approach to the mathematical modeling of nonlinear dynamic system of a black-box type represented by the Volterra polynomial of the N-th degree. The paper presents a new algorithm for the identification of Volterra polynomial of the second degree for non-stationary dynamic systems which allow an active experiment using test sets of input signals. This makes it possible for the input and output characteristics of the object to obtain an adequate and fast mathematical description. The results enable us to assess the applicability of this mathematical apparatus to the control of active components of electric power system in which power quality parameters are taken into account as an objective vector.