Creation of brand-new highly intelligent systematic and distribution electric grids in the Unified Energy System of Russia (intelligent grid - Smart Grid) is considered a priority of scientific and technical progress in the electricity industry according to the Energy Strategy of Russia for the period up to 2030. The concept of "Smart Grid" includes above all providing automated energy accounting; creation of intellectual protection and control; including alternative sources in the network of distributed power generation. One of the most important elements of modern electrical network is relay protection that provides localization of the damaged equipment for all possible fault regimes and minimize the amount of damage while maintaining the stability of the rest of the grid. The power system as a source and consumers with varying power consumption renders recognizing the fault regimes problematic due to various interfering factors, i.e. startups and self-startups of powerful electric motors, transformers switching to idle mode, large power flows on the transit lines, and the transient resistance of the electric arc at the fault location. Creation of state-of-the-art high-intelligence devices for relay protection at the stage of their development requires to verify functioning algorithms and to assess their ability to recognize the fault regime against the background of acceptable regimes. There has been developed a method for assessing information signs describing the regimes of electric networks with linear and polynomial decision functions. The article also proposes criteria for assessing information signs from the perspective of separating regime recognition areas. The authors discuss ways to build recognition systems in relation to relay protection of electric networks. (C) 2015 The Authors. Published by Elsevier Ltd.