Automation of the approximate method for estimating active power flows in an electric network with three buses according to specified parameters in nodes using an incomplete conductivity matrix and the implementation of calculations in the CVX format. is considered. The method is based on the fact that the active resistances of the power transmission lines in the electrical circuit are significantly less than the reactive ones, which makes it possible to obtain a simple relationship between the power in the nodes and the angles, which establishes the connection of the parameters of the nodes using a non-invertible conductivity matrix. CVX is a calculation format that allows you to introduce various constraints, including current density in lines, parametric changes, external perturbations, etc. The results of estimates of active power flows for possible variants of the node “zeroing” scheme by minimizing the Euclidean norm are presented. The practical application of the proposed method is determined by the need to quickly assess the volume of purchases in the electricity markets